Serological serum protein fraction and responses to Brucella melitensis in lambs fed aflatoxins

Twenty-four lambs were given 2 ppm aflatoxins (AF) in their diet for 37 d and 12 were kept as a control group. After this time, toxic feed was removed for a further 35 days (clearance period). On day 17 all lambs were vaccinated with B melitensis strain Rev-1, and blood samples were taken regularly to determine the levels of antibodies and serum proteins. Aflatoxins decreased titers of Rose Bengal test and optical densities of ELISA, both in the intoxicated and clearance periods. Complement fixation titers were lower in intoxicated lambs, except on the 23rd day of intoxication, but not statistically different (P > 0.05). No effect of AF was noted on total serum proteins, but albumin and alfa-globulin levels were lower for intoxicated lambs than for the control group. Beta-globulin concentration did not change, and increases in gamma-globulins levels in dosed lambs were observed throughout the experiment. These results suggest that AF causes a failure in the acquired immunity system of lambs by decreasing antibody production and altering serum profile proteins.

Cytosolic phospholipase A2 is coupled to muscarinic receptors in the human astrocytoma cell line 1321N1: characterization of the transducing mechanism

The cholinergic agonist carbachol induced the release of arachidonic acid in the 1321N1 astrocytoma cell line, and this was blocked by atropine, suggesting the involvement of muscarinic receptors. To assess the mechanisms of signalling involved in the response to carbachol, a set of compounds characterized by eliciting responses through different mechanisms was tested. A combination of 4beta-phorbol 12beta-myristate 13alpha-acetate and thapsigargin, an inhibitor of endomembrane Ca2+-ATPase that induces a prolonged elevation of cytosolic Ca2+ concentration, induced an optimal response, suggesting at first glance that both protein kinase C (PKC) and Ca2+ mobilization were involved in the response. This was consistent with the observation that carbachol elicited Ca2+ mobilization and PKC-dependent phosphorylation of cytosolic phospholipase A2 (cPLA2; phosphatide sn-2-acylhydrolase, EC 3.1.1.4) as measured by a decrease in electrophoretic mobility. Nevertheless, the release of arachidonate induced by carbachol was unaltered in media containing decreased concentrations of Ca2+ or in the presence of neomycin, a potent inhibitor of phospholipase C which blocks phosphoinositide turnover and Ca2+ mobilization. Guanosine 5'-[gamma-thio]triphosphate added to the cell-free homogenate induced both [3H]arachidonate release and cPLA2 translocation to the cell membrane fraction in the absence of Ca2+, thus suggesting the existence of an alternative mechanism of cPLA2 translocation dependent on G-proteins and independent of Ca2+ mobilization. From the combination of experiments utilizing biochemical and immunological tools the involvement of cPLA2 was ascertained. In summary, these data indicate the existence in the astrocytoma cell line 1321N1 of a pathway involving the cPLA2 which couples the release of arachidonate to the occupancy of receptors for a neurotransmitter, requires PKC activity and G-proteins and might operate in the absence of Ca2+ mobilization.

Posttranscriptional elevation of cytochrome P450 3A expression

Human CYP3A, the most abundant hepatic and intestinal cytochrome P450, catalyzes the metabolism of a diverse array of xenobiotics. Dimethyl sulfoxide is a commonly used solvent which has been used therapeutically. Dimethyl sulfoxide effects on CYP3A, CYP2E1, CYP2B and NADPH cytochrome P450 reductase expression in rat liver and in primary cultured rat hepatocytes were examined. Dimethyl sulfoxide increased immunodetectable hepatic CYP3A and CYP2E1 levels approximately 2.5 to 3-fold in the absence of any change in the respective mRNA levels. No change in CYP2B or P450 reductase expression was observed, indicating that dimethyl sulfoxide effects were selective. Dimethyl sulfoxide also increased CYP3A protein in rats pretreated with dexamethasone. In primary cultured rat hepatocytes, dimethyl sulfoxide increased CYP3A and CYP2E1 protein without increasing the respective mRNA levels. These results show that dimethyl sulfoxide, at levels relevant to human exposure, enhances CYP3A and CYP2E1 expression by posttranscriptional mechanisms.

Voltage- and GABA-evoked currents from Müller glial cells of the baboon retina

The electrophysiological features of isolated baboon Müller cells was investigated using the whole-cell voltage-clamp technique. Application of depolarizing voltage steps evoked transient inward and delayed outward currents. The transient currents disappeared when extracellular Na+ was replaced by choline+ and were substantially decreased by application of tetrodotoxin (1 microM). The outward currents were strongly diminished by extracellular Ba2+ (1 mM), and the hyperpolarization-generated inward currents disappeared following application of Ba2+. The recently described gamma-aminobutyric acid A (GABAA) receptor currents were increased by flunitrazepam, nordiazepam, pentobarbital and Zn2+, as well as by the inverse agonist DMCM. These results suggest that the baboon Müller cells possess the same voltage-dependent current pattern as those from other species, e.g. humans, whereas their GABAA receptors react in an uncharacteristic manner to DMCM and Zn2+, when compared with neuronal GABAA receptors.

Reaction patterns in selected lymphatic tissues associated with sudden infant death (SID)

In 50 cases of sudden infant death cervical, paratracheal and lung hilar lymph nodes, the thymus and the spleen were investigated by histology and immunohistochemistry (CD 20, 21, 45RO). The cases were divided into 3 groups based on autopsy findings including extensive histology: A --without pathological changes (N = 12), B --with minimal to intermediate inflammation (N = 23) and C --with severe inflammation (N = 15). In accordance with previous results the frequency of "pathological" lymph node changes, such as paracortical lymphoid hyperplasia and variegated hyperplasia of the pulp increased from group A to group C. The B-cell antigens reacted accordingly. A pronounced lymphodepletation of the thymus as a sign of a long lasting stimulation of the T-cell system was also observed increasingly from group A to C. In summary, in none of the cases results obtained were indicative of a defect of the T- or B-cell system. The results in group A seem to indicate that changes in the reaction pattern of the lymphoid tissues could be a more sensitive method of detection of early stages of inflammation than local histology.

Vertical HIV-1 transmission correlates with a high maternal viral load at delivery

Transmission of HIV-1 from an infected mother to her child occurs in around 20% of cases. Although maternal, immunological, and virological factors have been implicated in transmission, clear association is not yet well defined. For this reason, we have conducted a study to determine the relative contribution of the above-mentioned factors with special emphasis on quantitative viral load. We studied 67 HIV-1-infected mothers during pregnancy and labor and their 69 newborns (two sets of twins) from two university hospitals in Barcelona. Plasma and cell samples were collected at delivery between January 1992 and May 1994, and HIV-1 RNA and p24 in plasma, CD4 cell counts, and tissue culture infectious doses (TCID) were measured. Diagnosis of infection in children was based on persistence of anti-HIV-1 antibodies at 18 months of age, a positive HIV-1 culture or polymerase chain reaction in two separate samples, or presence of signs or symptoms of AIDS before 18 months of age. Results showed a very high relationship between > 10(5)/ml viral RNA copies (odds ratio [OR] 22, 95% confidence interval [CI] 4.4-119.2, p < 0.00001), > 0.5 TCID (OR 17, 95% CI 2.1-139.7, p = 0.001), CDC B + C (OR 3.5, 95% CI 0.98-12.5, p = 0.055), < 400 CD4 cells (OR 4.1; 95% CL 1.1-15.4, p = 0.01) and transmission of HIV-1. In this study, a strong association between mother-to-child transmission of HIV-1 and a high maternal viral RNA load in plasma at delivery is demonstrated. Viral load, which is related to clinical and immunological status in the mother, is the main contributing factor for HIV-1 vertical transmission, and these findings may have global and even individual therapeutic implications.

Stability of amphotericin B in an extemporaneously prepared i.v. fat emulsion

The stability of amphotericin B in an extemporaneously prepared i.v. fat emulsion was studied. Admixtures of amphotericin B 0.5, 1, and 2 mg/mL were prepared by adding 10, 20, and 40 mL of amphotericin B 5 mg/mL to 90, 80, and 60 mL, respectively, of 20% fat emulsion. The admixtures were stored in glass vacuum containers at 20-25 degrees C and exposed to fluorescent light, 20-25 degrees C and protected from light, or 4-8 degrees C and protected from light. A sample was withdrawn from each container at 0, 4, 12, and 24 hours and at 2, 4, 7, and 15 days for analysis of amphotericin B concentration by high-performance liquid chromatography and for visual evaluations; these samples were immediately frozen until analyzed. A sample was withdrawn from one container of amphotericin B 1 and 2 mg/mL for each storage condition at 0, 7, and 15 days for immediate determination of particle-size distribution with a fluorescinated-antibody cell sorter. Amphotericin B 0.5 mg/mL in 20% fat emulsion was stable for one week under all the storage conditions. Amphotericin B in the 1- and 2-mg/mL admixtures was stable for up to four days at 20-25 degrees C exposed to fluorescent light, and for up to one week at 20-25 degrees C protected from light and at 4-8 degrees C protected from light. There was no visible evidence of incompatibility. There were no substantial changes in particle-size distribution for the 1-mg/mL admixtures; appreciable changes were detected for the 2-mg/mL admixtures. Amphotericin B 1 and 2 mg/mL was stable in 20% fat emulsion for four days at 20-25 degrees C exposed to fluorescent light and for seven days at 20-25 degrees C protected from light or at 4-8 degrees C; amphotericin B 0.5 mg/mL was stable in 20% fat emulsion for seven days under the three storage conditions.

Inferior vena caval blood flow and cardiac hemodynamics during carbon dioxide pneumoperitoneum

BACKGROUND

The effects of carbon dioxide pneumoperitoneum on venous return and cardiac hemodynamics during laparoscopic surgery were studied.

METHODS

Twelve adult pigs underwent placement of an electromagnetic flow meter across the infrarenal vena cava (IVC) as well as placement of Swan Ganz and arterial monitoring catheters. Measurements of the flow through infrarenal IVC, cardiac output (CO), pulmonary capillary wedge pressure (PCWP), mean arterial pressure (MAP), and heart rate were recorded at baseline, 5 and 60 min following insufflation to 15 mmHg with CO2, and 5 min following desufflation. Stroke volumes and systemic vascular resistance (SVR) were calculated as well.

RESULTS

Flow through the IVC dropped by 24 and 31% at 5 and 60 min (p = 0.03 and 0.02, respectively). Paradoxically, cardiac output rose by 14 and 28% at 5 and 60 min (p = 0.03 at 60 min). Central venous and pulmonary capillary wedge pressures rose transiently by 35 and 36% at 5 min before returning to baseline (p < 0.01). Mean arterial pressure and heart rate remained relatively constant during insufflation. Systemic vascular resistance diminished from 938 dynes/cm/s prior to insufflation to its nadir at 60 min of 650 dynes/cm/s (p < 0.01).

CONCLUSIONS

These observations suggest potentially complex interactions between the mechanical and systemic effects of the CO2 pneumoperitoneum on venous return. Transient elevations in cardiac filling pressures occur by an unknown mechanism, and a generalized enhanced inotropic state mediated via increased sympathetic outflow is observed in this hypercapnic anesthetized animal model.

Development of a common variable immunodeficiency in IgA-deficient patients

IgA deficiency (IgA-D) and common variable immunodeficiency (CVID) are two primary immunodeficiencies that share clinical features. Occasionally, both diseases have been diagnosed in the same family, which suggests the existence of some common pathogenic mechanism, but progression from IgA-D to CVID has rarely been documented. We report three cases of CVID diagnosed 1 to 12 years after IgA-D was detected. Two of these patients presented autoimmune diseases followed by a progressive decline in IgG levels. They are currently on intravenous immunoglobulin therapy with complete remission of their autoimmune and infectious symptoms.

Very late presentation of vertically transmitted HIV-1 infection

We describe a 13-year-old boy with a very late presentation of vertically transmitted HIV-1 infection. The mother, an intravenous drug user before pregnancy, was diagnosed with AIDS in 1987 when the boy was 6 years old. HIV infection in her son was never suspected or investigated. No other risk factors for this infection can be attributed to the boy. On diagnosis of the infection the boy had moderately severe respiratory symptoms, as classified in category B2 of the 1994 paediatric HIV infection definition, and virological replicative kinetics and the phenotype have been determined. Standard AZT therapy has improved the clinical symptoms, with negativization of plasma p24 Ag and HIV RNA. Clinicians should be aware of this form of presentation of HIV-1 infection to avoid further delay of proper therapy.

Cysticercosis: identification and cloning of protective recombinant antigens

We describe the cloning and the evaluation of the protective capacity of 5 recombinant antigens expressed during the cysticercus stage of both Taenia crassiceps and Taenia solium. A cDNA library was constructed in bacteriophage lambda ZAP using mRNA isolated from larvae of T. crassiceps of the ORF strain. The recombinant phage library was screened with polyclonal antibodies against 56- and 74-kDa protective antigen fractions. This screening identified 13 recombinant clones, 5 of which were also strongly recognized by pooled sera from pigs experimentally infected with T. solium. The native antigens are proteins of 56 (clones KETcl, 4, 7) and 74 and 78 kDa (clones KETc11, 12) of T. crassiceps cysticerci. Vaccination experiments using these 5 recombinant clones against murine cysticercosis point to the relevance of KETcl, 4, 7, and 12 in host protection, whereas immunization with the clone KETc11 does not modify the parasite load in females and facilitates the parasitosis in males. We report here the DNA and the deduced amino acid sequence (100 amino acids) of the first protective antigen (KETc7) of potential interest for T. solium pig cysticercosis prevention.

Immunodominant synthetic peptides of Taenia crassiceps in murine and human cysticercosis

The screening of a cDNA library of Taenia crassiceps revealed a clone designated KETc7 that induced high levels of protection against murine cysticercosis in previous experiments. The molecular structure of the deduced 100-amino acid sequence of the corresponding proline-rich polypeptide was studied to detect potentially immunologically active epitopes. Several candidate epitopes were identified, three of which were synthesized by solid-phase peptide synthesis and used as antigens in enzyme-linked immunosorbent assay (ELISA) for detection of specific antibodies in a selected panel of sera from mice infected with Taenia crassiceps and pigs infected with Taenia solium, as well as in the serum and cerebrospinal fluid of human patients with neurocysticercosis. The three peptides detected antibodies in serum from all infected mice. Seven of nine sera from patients with neurocysticercosis reacted strongly with peptide GK-3, and four of them with peptides GK-1 and GK-2. A lower reactivity was observed in sera from experimentally infected pigs. Peptide GK-3 reacted also with 45 out of 77 cerebrospinal fluids (CSF) from patients with confirmed neurocysticercosis and with 14 out of 68 CSF from control patients with other neurological disorders. This is the first report on synthetic peptides that are prominent in the humoral response of murine, porcine and human cysticercosis. Their identification implies finer molecular tools in the exploration of this form of host-parasite relationship, as well as hints to their application in immunodiagnosis and in vaccine design.

GABAA receptor currents recorded from Müeller glial cells of the baboon (Papio cynocephalus) retina

The effect of gamma-aminobutyric acid (GABA) application on acutely isolated, non-cultivated Muller glial cells from the baboon retina was studied using the whole-cell voltage-clamp technique. Application of GABA (0.1 mM) generated inward currents at a holding potential of -80 mV as well as an increase in current noise. The GABA-activated current had a reversal potential of 18.6 mV and was therefore supposed to be a Cl- current (ECl = 5 mV). The GABAA receptor agonist muscimol (0.1 mM) elicited an inward current and bicucullin (0.5 mM), a blocker of the GABAA receptor, diminished the GABA responses in our experiments completely. Baclofen (0.1 mM), a GABAB agonist, neither had an effect when applied under conditions where the dominant Muller cell K+ currents were unblocked, nor when the K+ currents were blocked by application of Ba2+ (1 mM). Glycine (0.1 mM) was ineffective as well. From these results we conclude that the baboon retinal Muller cells possess GABAA receptors. However, these have recently been discovered on skate Muller cells whereas GABAA receptors could not be found on Muller cells of guinea pig, pig, mouse, rat and rabbit.

[Clinical trial with tibolone in postmenopausal replacement therapy]

Estrogen deficiency is the basic change in women around the climateric stage. This hormone deficiency is different among women regarding the age and intensity of symptoms. The hormone replacement has proved its benefit on relieve of symptoms and long term effect on prevention of cardiovascular disease and osteoporosis. A new pharmacological agent Tibolona has been studied recently as replacement therapy. This work reports the results obtained with the use of Tibolona in 36 postmenopausal women. The effectiveness and security were confirmed as well as the low occurrence of side effects. It was also apparent that this therapy had a relevant effect on the psycho-emotional component and upon the improvement of sexual satisfaction and activity.

Urinary cadmium levels during pregnancy and postpartum. A longitudinal study

It is well established that pregnancy induces physiological, metabolical and hormonal changes. As a consequence, trace metal metabolism can be affected. The aim of the present study was to assess the urinary cadmium levels in women during gestation and postpartum. The survey was conducted in a group of nonoccupationally cadmium-exposed women from Southern Catalonia (NE, Spain). Urine samples were obtained before pregnancy, during the 6th, 10th, 26th, and 30th wk of gestation, as well as during the 5th and 24th wk after delivery. Urinary cadmium levels were determined by graphite furnace atomic absorption spectrophotometry. The concentrations of zinc and copper in plasma were also measured. Moreover, to assess the effect of the diet during pregnancy, dietary ingestions of zinc, iron, and calcium were also determined. A significant decrease of plasma zinc levels could be observed during the last two trimesters of pregnancy, while plasma copper concentrations significantly increased during the same period. Urinary cadmium concentrations ranged from 0.05 to 3.79 micrograms/g creatinine (geometric mean 0.49 +/- 2.26 micrograms/g creatinine). No significant changes in urinary cadmium concentrations during pregnancy and postpartum could be observed.

Older children and adolescents living with perinatally acquired human immunodeficiency virus infection

OBJECTIVE

To describe the clinical, immunologic, and psychosocial characteristics of children living with perinatally-acquired human immunodeficiency virus (HIV) infection beyond the age of 9 years.

METHODS

This is a descriptive cohort study of 42 surviving perinatally infected children older than 9 years followed at the Children's Hospital Acquired Immunodeficiency Syndrome (AIDS) Program (part of a university-based inner city medical center) as of June 1993. The study is based on medical record data of clinical, immunologic, and psychosocial parameters.

RESULTS

The cohort includes 20 boys and 22 girls with a mean age of 136 months. The mean age at diagnosis of HIV infection was 88 months, and 59.5% were asymptomatic at the time of diagnosis. Currently, after a mean follow-up period of 48 months from diagnosis, 23.8% remain asymptomatic, 19.1% have non-AIDS-defining HIV-related symptoms, and 57.1% have AIDS; 85.7% of the cohort did not develop HIV-related symptoms until after 48 months of age (late-onset prolonged survivors). There was an average annual decline of 71.4 CD4+ cells/microL in the cohort from the ages of 7 to 16 years, and 21.4% have a current CD4+ lymphocyte count of greater than 500 cells/microL, 28.6% between 200 and 500 cells/microL, and 50% less than 200 cells/microL; 76% are orphaned as a result of maternal death, with the majority of the cohort (60%) cared for by extended family members. Disclosure of diagnosis has occurred in 57.1%. The vast majority of the cohort (76%) are attending regular school, with the remainder in special education.

CONCLUSIONS

Although close to one quarter of the children and adolescents ages 9 to 16 years living with perinatally acquired HIV infection described in this cohort remain asymptomatic and have a relatively intact immune system, the remainder are living with significant HIV-related symptoms, many of which are chronic in nature and have an impact on daily living. The children in this cohort had both significant immunologic deterioration and symptomatic disease progression during the mean follow-up period of 48 months from the time of diagnosis with HIV infection.

[Prevalence of antibodies against hepatitis C virus in multitransfused patients]

We have done a study in order two know the prevalence of anti-hepatitis C virus antibodies in polytransfused patients with hemophilia, leukemia and hemolytic anemia, along with 17 healthy donors, without previous history of transfusions. We analyzed samples from 10 hemophilic patients and 12 from leukemia, lymphoma and hemolytic anemia, all of them had received blood or blood products, at least six months before the study. Using a second generation ELISA, 4 positive sample (3 hemophilic and 1 lymphoma) were detected (10.26%), which represent a prevalence of 30% in the hemophilic group, in contrast with the prevalence detected in other countries. A very significant statistic association was demonstrated, between the positive ELISA, the amount of the transfused product (P < 0.0004) and the type of blood product used for transfusion (crioprecipited, P = 0.000, plasma P = 0.000).