Proteolytic dissection of band 3, the predominant transmembrane polypeptide of the human erythrocyte membrane

Band 3 is the major, membrane-spanning, approximately90 000 dalton polypeptide of the human erythrocyte membrane. To facilitate the analysis of its structural integration into the membrane, we have cleaved this protein in situ into large fragments and ascertained their disposition. Digestion of intact cells with chymotrypsin yielded band 3 fragments with apparent molecular weights of 38 000 and 55 000. Both fragments resisted elution by NaOH and acetic acid, suggesting that they are anchored in the apolar core of the membrane. Both pieces communicate with the extracellular space, and the 55 000 dalton species extends to the cytoplasmic surface as well. Digestion of unsealed ghosts with chymotrypsin produced a hydrophobic 17 000 dalton species, a segment of the 55 000 dalton fragment, which spans and is firmly anchored in the core of the membrane. Trypsin and papain at low concentration generated integral band 3 fragments of 52 000 daltons and released major band 3 fragments of less than or equal to 41 000 daltons from the cytoplasmic side of the membrane. The latter water-soluble polypeptides remained associated in discrete complexes which retained the capacity to bind glyceraldehyde-3-phosphate dehydrogenase. An interchain disulfide bond, which can be induced only at the cytoplasmic surface, cross-linked intact band 3, and certain of its water-soluble fragments. Finally, fragments of 23 000 daltons were generated from the innersurface domain by reacting disulfide-linked band 3 dimers with cyanide or reduced polypeptides with 2-nitro-5-thiocyanobenzoate. A provisional ordering of these fragments is proposed.

Venezuelan haemorrhagic fever

An outbreak of severe haemorrhagic illness began in the municipality of Guanarito, Portuguesa State, Venezuela, in September, 1989. Subsequent detailed study of 15 cases confirmed the presence of a new viral disease, designated Venezuelan haemorrhagic fever. Characteristic features are fever, toxicity, headache, arthralgia, diarrhoea, conjunctivitis, pharyngitis, leucopenia, thrombocytopenia, and haemorrhagic manifestations. Other features include facial oedema, cervical lymphadenopathy, nausea/vomiting, cough, chest or abdominal pain, and convulsions. The patients ranged in age from 6 to 54 years; all were residents of rural areas in central Venezuela, and 9 died. Infection with Guanarito virus, a newly recognised arenavirus, was shown by direct culture or by serological confirmation in all cases. Epidemiological studies suggest that the disease is endemic in some rural areas of central Venezuela and that it is rodent-borne. Venezuelan haemorrhagic fever has many similarities to Lassa fever and to the arenavirus haemorrhagic fevers that occur in Argentina and Bolivia.

Comparison of survival in continuous ambulatory peritoneal dialysis and hospital haemodialysis: a multicentric study

We compared the survival of 842 patients on centre haemodialysis to 272 patients on continuous ambulatory peritoneal dialysis (CAPD). All patients selected had begun treatment between 1 January 1984 and 30 June 1988 and were from six centres which participate in a regional renal patients registry. Patients on CAPD were older and had a greater proportion of diabetes and other associated diseases. Age, diabetes, and cardiovascular diseases were associated with a shorter survival on treatment in all the patients studied. Without adjustment for risk factors, patient 3-year survival was higher in centre haemodialysis than in CAPD, 80% versus 64% respectively. However, no significant differences could be shown in the survival rates of the two treatment modalities after accounting for the heterogeneity of the patients in the two groups, either by stratification or by multivariate analysis (Cox). Age was the main predictive factor for CAPD patient survival, while the influence of diabetes and cardiovascular diseases was less clear. Technique survival was much better in centre haemodialysis (94% versus 56% in CAPD, 3-year survival). Older age and diabetes mellitus were associated with a greater risk of switching from centre haemodialysis to CAPD and a trend to retain those patients on CAPD.

Cell confluency is as efficient as serum starvation for inducing arrest in the G0/G1 phase of the cell cycle in granulosa and fibroblast cells of cattle

The cell cycle stage of donor cells is an important factor influencing developmental ability of nuclear transfer embryos. In the present experiment, cumulus and fibroblast cells of cattle were subjected to flow cytometric cell cycle analysis before being used in somatic cloning experiments. The following experimental groups were analyzed for each cell type: (1) actively dividing cells, (2) cells confluent for 4 days, (3) cells starved for 1, 2, 3 or 5 days. Using the propidium iodide flow cytometric assay, there were no significant differences (P > or = 0.05) in the percentage of cells in G0/G1 regardless of origin and type of cell, after confluency or serum starvation. Differences with the growing cells were found (P < or = 0.01). To determine what subset of cells in G0/G1 were in the G0 subphase of the cell cycle, an immunofluorescence analysis was conducted using monoclonal anti-PCNA antibodies in a FACS assay. There were not statistically significant differences in the percentage of cells that enter G0, between confluent and any starved group for either type of cells. Bovine fibroblast cells, confluent or serum starved for 3 days, were used in nuclear transfer experiments. A slight trend for a more desirable fusion rate in starved cells was detected, and embryo cleavage was greater in starved cells, however, in vitro development to blastocysts was similar between groups. Data indicate that prolonged culture of cells in the absence of serum does not imply a shift in the percentage of cells that enter G0/G1 or G0 alone, and that confluency is sufficient to induce quiescence. This finding can be beneficial in nuclear transfer programs, because there are negative effects such as apoptosis, associated with serum starvation.

Isolation and characterization of pirital virus, a newly discovered South American arenavirus

Specific rodent species are principal hosts for each of the well-characterized members of the virus family Arenaviridae. Guanarito virus (Arenaviridae) is the etiologic agent of Venezuelan hemorrhagic fever. A previous study on the epidemiology of Venezuelan hemorrhagic fever revealed extensive arenavirus infection (presumed to be caused by Guanarito virus) in two rodent species. Sigmodon alstoni and Zygodontomys brevicauda, collected from the region of Venezuela in which the disease is endemic. In the present study, four arenavirus isolates recovered from the Municipality of Guanarito (two isolates each from S. alstoni and Z. brevicauda) were characterized to learn more about the natural rodent host relationships of Guanarito virus. Serologic tests and analyses of nucleocapsid protein gene sequence data indicated that the two isolates from Z. brevicauda are strains of Guanarito virus and that the two isolates from S. alstoni are representatives of a novel New World arenavirus (proposed name Pirital) that is antigenically and phylogenetically distinct from all known New World arenaviruses. The results of the present study provide further evidence that the cane mouse Z. brevicauda is a natural host of Guanarito virus and suggest that the cotton rat S. alstoni is the natural reservoir host of Pirital but not Guanarito virus.

Transgenic rabbits as bioreactors for the production of human growth hormone

Gene farming is one of the most promising areas in modern biotechnology. To assay the potential usefulness of transgenic rabbits as bioreactors, one call embryos were microinjected with a chimeric gene comprising 5' sequences from mouse whey acidic protein gene (mWAP) linked to the human growth hormone (hGH) gene. Transgenic animals were obtained and the presence of the foreign protein was detected in the milk and serum of these animals at levels of up to 50 micrograms ml-1 and 0.6 ng ml-1, respectively. Founder transgenics were able to transmit the microinjected gene to the first filial generation in a Mendelian fashion. These results showed that transgenic rabbits could constitute a suitable system for the rapid production of recombinant proteins in the milk of lactating females.

Production of transgenic mice and rabbits that carry and express the human tissue plasminogen activator cDNA under the control of a bovine alpha S1 casein promoter

One-cell embryos from mice and rabbits were microinjected with a hybrid gene composed of 1.6 kilobases (kb) promoter/regulatory sequences of the bovine alphaS1 casein gene fused to the complementary DNA (cDNA) encoding for the human tissue plasminogen activator (htPA) and 3'untranslated sequences from rabbit beta-globin and SV 40 genes. Transgenic mice and rabbits that carry the htPA gene were obtained. In mice, 11 founder females were generated, and 6 of them expressed low levels (about 50 mug/ml) of htPA in their milk. Some of the transgenic mice showed rearrangements of the microinjected DNA sequences as judged by Southern blot analysis. A position-dependent expression of the transgene is suspected to occur. The only live-born founder transgenic rabbit obtained was a male, and it transmitted the transgene in a Mendelian fashion to F1 females, which expressed htPA at very low levels (8 to 50 ng/ml). Although the 1.6-kb bovine alphaS1 casein promoter that was used directs the synthesis of htPA specifically to the mammary gland, it may not be sufficient for a high level of expression.

Priming of pathogenesis related-proteins and enzymes related to oxidative stress by plant growth promoting rhizobacteria on rice plants upon abiotic and biotic stress challenge

Two plant growth promoting rhizobacteria (PGPR) were tested to evaluate their capacity to prime rice seedlings against stress challenge (salt and Xanthomonas campestris infection). As is accepted that plants respond to biotic and abiotic stresses by generation of reactive oxygen species (ROS), enzyme activities related to oxidative stress (ascorbate peroxidase (APX, EC 1.11.1.11), guaiacol peroxidase (GPX, EC 1.11.1.7), glutathione reductase (GR, EC 1.6.4.2) and superoxide dismutase (SOD, EC 1.15.1.1)) as well as the pathogenesis-related proteins (PRs) ß-1,3-glucanase (PR2, EC 3.2.1.6) and chitinase (PR3, EC 3.2.1.14) were measured at 3 time points after stress challenge. In addition, photosynthetic parameters related with fluorescence emission of photosystem II (F0, Fv/Fm, ΦPSII and NPQ) were also measured although they were barely affected. Both strains were able to protect rice seedlings against salt stress. AMG272 reduced the salt symptoms over 47% with regard to control, and L81 over 90%. Upon pathogen challenge, 90% protection was achieved by both strains. All enzyme activities related to oxidative stress were modified by the two PGPR, especially APX and SOD upon salinity stress challenge, and APX and GR upon pathogen presence. Both bacteria induced chitinase activity 24 and 48 h after pathogen inoculation, and L81 induced ß-1,3-Glucanase activity 48 h after pathogen inoculation, evidencing the priming effect. These results indicate that these strains could be used as bio-fortifying agents in biotechnological inoculants in order to reduce the effects of different stresses, and indirectly reduce the use of agrochemicals.

Critical role of ribavirin for the achievement of early virological response to HCV therapy in HCV/HIV-coinfected patients

The response to hepatitis C virus (HCV) therapy seems to be lower in HCV/HIV-coinfected patients than in HCV-monoinfected individuals. Given that most pivotal trials conducted in coinfected patients have used the combination of pegylated interferon (pegIFN) along with fixed low doses (800 mg/day) of ribavirin (RBV), it is unclear whether HIV itself and/or suboptimal RBV exposure could explain this poorer outcome. Two well-defined end points of early virological response were evaluated in Peginterferon Ribavirina España Coinfección (PRESCO), a multicentre trial in which the combination of pegIFN plus RBV (1000 mg if body weight <75 kg and 1200 mg if >75 kg) was prescribed to coinfected patients. For comparisons, we used unpublished data from early kinetics in two other large trials, one performed in HIV-negative patients [Pegasys International Study Group (PISG)] in which RBV 1000-1200 mg/day was used and another [AIDS Pegasys Ribavirin Coinfection Trial (APRICOT)] in which HIV-positive patients received fixed low RBV doses (800 mg/day). A total of 348 HCV/HIV-coinfected patients from the PRESCO trial were analysed as well as all patients treated with pegIFN plus RBV, who completed 12 weeks of therapy in the comparative studies (435 in PISG and 268 in APRICOT). Negative serum HCV-RNA at week 4 (which has the highest positive predictive value of sustained virological response, SVR) was attained in 33.3%, 31.2% and 13% of treated patients with HCV genotype 1, respectively, in PRESCO, PISG and APRICOT. For HCV genotypes 2/3, responses were 83.7%, 84.2% and 37%, respectively. A decline lower than 2 log(10) at week 12 (which has the highest negative predictive value of SVR) was seen in 25.5%, 19.5% and 37% of HCV genotype-1-infected patients, and in 2.1%, 2.9% and 12% of genotypes-2/3-infected patients, respectively. Prescription of high RBV doses enhances the early virological response to HCV therapy in HCV/HIV-coinfected patients, with results approaching those seen in HCV-monoinfected patients.

Screening for putative PGPR to improve establishment of the symbiosis Lactarius deliciosus-Pinus sp

A screening for plant growth promoting rhizobacteria (PGPR) was carried out in the mycorrhizosphere of wild populations of Pinus pinea and P. pinaster, and in the mycosphere of associated Lactarius deliciosus. A total of 720 bacteria were isolated, purified, and grouped by morphological criteria. Fifty percent of the isolates were selected and tested for aminocyclopropanecarboxylic acid (ACC) degradation, auxin and siderophore production, and phosphate solubilization. Thirty eight percent of the isolates showed at least one of the evaluated activities. Nutrient-related traits were associated with P. pinaster, whereas hormone production traits predominated in P. pinea. These activities were found mostly in Gram positive isolates. After PCR-RAPDs (random amplified polymorphic DNA) analysis, 10 groups appeared with 85% similiarity when considering all isolates, indicating the low diversity in the system. One strain of each group was identified by 16S rDNA sequencing. Our results suggest that P. pinaster selects for mycorrhizosphere bacteria that mobilize nutrients, whereas P. pinea selects for bacteria that have the capacity to increase root growth via production of plant growth regulators.

The demography and characteristics of SARS-CoV-2 seropositive residents and staff of nursing homes for older adults in the Community of Madrid: the SeroSOS study

Background: Nursing homes for older adults have concentrated large numbers of severe cases and deaths for COVID-19.

Methods: Point seroprevalence study of nursing homes to describe the demography and characteristic of SARS-CoV-2 IgG-positive residents and staff.

Results: Clinical information and blood samples were available for 9,332 residents (mean age 86.7 ± 8.1 years, 76.4% women) and 10,614 staff (mean age 45.6 ± 11.5, 86.2% women). Up to 84.4% of residents had frailty, 84.9% co-morbidity and 69.3% cognitive impairment; 65.2% of workers were health-aides.

COVID-19 seroprevalence was 55.4% (95% CI, 54.4–56.4) for older adults and 31.5% (30.6–32.4) for staff. In multivariable analysis frailty of residents was related with seropositivity (OR: 1.19, p = 0.02). In the case of staff, age > 50 years (2.10, p < 0.001), obesity (1.19, p = 0.01), being a health-aide (1.94, p < 0.001), working in a center with high seroprevalence in residents (3.49, p < 0.001), and contact with external cases of COVID-19 (1.52, p < 0.001) were factors associated with seropositivity. Past symptoms of COVID-19 were good predictors of seropositivity for residents (5.41, p < 0.001) and staff (2.52, p < 0.001).

Conclusions: Level of dependency influences risk of COVID-19 among residents. Individual and work factors, and contacts outside the nursing home are associated with COVID-19 exposure in staff members. It is key to strengthen control measures to prevent the introduction of COVID-19 into care facilities from the community.

Inhibition of phosphatidylcholine synthesis precedes apoptosis induced by C2-ceramide: protection by exogenous phosphatidylcholine

Cerebellar granule neurons in primary culture underwent apoptosis when exposed to C2-ceramide. Addition of exogenous phosphatidylcholine (PtdCho) resulted in a dose-dependent full prevention of neuronal death. Exogenous PtdCho also prevented apoptosis induced by farnesol, N-oleoylethanolamine, and sphingomyelinase, but did not prevent apoptosis induced after lowering the potassium concentration in the medium to non-depolarizing levels. Moreover, C2-ceramide inhibited labeling of [32P]PtdCho in cells incubated with [32P]orthophosphate, with the same potency to that causing apoptosis. Although cell viability did not decrease during the first few hours, inhibition of PtdCho synthesis was already patent after a 1 h exposure to C2-ceramide. Taken together, these results strongly suggest that inhibition of PtdCho synthesis constitutes one of the primary events by which C2-ceramide triggers apoptosis in cerebellar granule neurons.

Analysis of laser-induced plasmic DNA photolysis by capillary electrophoresis

Capillary electrophoresis (CE) was used to monitor the laser-induced conversion of supercoiled pKOL8UV5 plasmid DNA into nicked conformers. The plasmid samples (0.1 mg/ml) were incubated in the absence or presence of 110 mumol/l ethidium bromide (EB) and then exposed to 100 J of argon laser radiation (488 nm). The nicked, open circular conformers were separated from the supercoiled DNA by a 15% increase in retention time. Approximately 90% of the control DNA was in the supercoiled form. Laser radiation in the presence of EB caused complete conversion of the supercoiled plasmid DNA into nicked conformers. Laser-induced fluorescence CE (LIF-CE) was about 100-fold more sensitive than UV-CE in the detection of these conformers. Agarose gel electrophoresis confirmed these findings and showed the presence of the nicked plasmid conformers. Based on these comparisons, CE is an efficient analytical tool for the identification of laser-induced conformational changes in plasmid DNA.

Prevalence between different alpha subunits performing the benzodiazepine binding sites in native heterologous GABA(A) receptors containing the alpha2 subunit

The presence of two heterologous alpha subunits and a single benzodiazepine binding site in the GABA(A) receptor implicates the existence of pharmacologically active and inactive alpha subunits. This fact raises the question of whether a particular alpha subtype could predominate performing the benzodiazepine binding site. The hippocampal formation expresses high levels of alpha subunits with different benzodiazepine binding properties (alpha1, alpha2 and alpha5). Thus, we first demonstrated the existence of alpha2-alpha1 (36.3 +/- 5.2% of the alpha2 population) and alpha2-alpha5 (20.2 +/- 2.1%) heterologous receptors. A similar alpha2-alpha1 association was observed in cortex. This association allows the direct comparison of the pharmacological properties of heterologous native GABA(A) receptors containing a common (alpha2) and a different (alpha1 or alpha5) alpha subunit. The alpha2 subunit pharmacologically prevailed over the alpha1 subunit in both cortex and hippocampus (there was an absence of high-affinity binding sites for Cl218,872, zolpidem and [3H]zolpidem). This prevalence was directly probed by zolpidem displacement experiments in alpha2-alpha1 double immunopurified receptors (K(i) = 295 +/- 56 nM and 200 +/- 8 nM in hippocampus and cortex, respectively). On the contrary, the alpha5 subunit pharmacologically prevailed over the alpha2 subunit (low- and high-affinity binding sites for zolpidem and [3H]L-655,708, respectively). This prevalence was probed in alpha2-alpha5 double immunopurified receptors. Zolpidem displayed a single low-affinity binding site (K(i) = 1.73 +/- 0.54 microM). These results demonstrated the existence of a differential dominance between the different alpha subunits performing the benzodiazepine binding sites in the native GABA(A) receptors.

Comparison of nucleic acid and protein immunization for induction of antibodies specific for HIV-1 gp120

We have compared the antibody response to HIV-1 gp120 type LAI in mice immunized with either a gp120 expression plasmid or with baculovirus-derived recombinant gp120 (rgp120) formulated with Freund's complete adjuvant. TiterMax, Alum, Ribi R-700, AF-A or QuilA. DNA immunization resulted in variable levels of antibody, with endpoint titres ranging from 10(4) to 10(5), whereas mice immunized with rgp 120 mixed with Ribi R-700, AF-A or QuilA produced antibody levels with endpoint titres > 10(5). Both types of immunization failed to elicit antibodies able to recognize denatured rgp120. The V3 region was immunogenic in animals immunized with nucleic acid, whereas only a few animals immunized with recombinant protein produced antibodies specific for V3 or other linear epitopes, irrespective of the adjuvant used. These data suggest that the immunogenicity of gp120 is dependent upon the mode of antigen delivery, and that in vivo expressed gp120 following nucleic acid immunization elicits, at least with respect to V3, an antibody response which more closely reflects that seen following natural infection in man.

Relative contributions of the components of the American College of Rheumatology 20% criteria for improvement to responder status in patients with early seropositive rheumatoid arthritis

OBJECTIVE

To evaluate factors that influence the responses defined by the American College of Rheumatology (ACR) 20% criteria for improvement in rheumatoid arthritis (RA).

METHODS

ACR 20% and 50% response rates were calculated from data collected for the intervals 0-6, 0-12, and 0-24 months for 180 RA patients participating in the Western Consortium of Practicing Rheumatologists long-term observational study of early seropositive RA (mean +/- SD duration of RA at study entry 6.0 +/- 3.4 months). Analyzable cases were patients with paired data for tender and swollen joint counts plus at least 3 of the following criteria: physician's and patient's global assessments of disease activity and patient's score for pain (by visual analog scale), physical function score on the Health Assessment Questionnaire (HAQ), and levels of an acute-phase reactant. Response rates were then recalculated by 3 different methods: 1) using only cases with complete paired data for all criteria, 2) sequentially assuming no improvement in each of the 5 secondary criteria, and 3) substituting grip strength for HAQ scores.

RESULTS

Using 464 paired observations for all analyzable cases, ACR 20% (50%) improvement rates were 52.6% (33.0%), compared with 55.6% (34.8%) for 365 paired observations from the cases with complete data. Decreases in ACR response rates when secondary criteria were sequentially set at "no improvement" ranged from 11.7% (pain at 0-6 months) to 1.2% (C-reactive protein at 0-12 months), but these were not statistically different by the kappa statistic. Overall numerical rankings of the relative contributions of the secondary criteria to the ACR 20% or 50% response rates were physician's global assessment, pain, HAQ, patient's global assessment, and acute-phase reactant. Only 7.8% of paired grip strength observations showed > or =20% improvement, compared with 71% of paired HAQ observations.

CONCLUSION

The use of all "analyzable" cases (paired data for tender and swollen joint counts plus > or =3 of the 5 secondary criteria) increases the number of subjects and only slightly decreases the ACR response rate compared with analyses limited to cases with complete data. The contributions of the secondary criteria are not statistically different, supporting their equal weighting in the ACR definition of improvement. The ACR 20% response rates are higher when the HAQ, rather than grip strength, is used to measure physical function.

Transgenic rabbits for the production of biologically-active recombinant proteins in the milk

The use of live bioreactors for the expression of human genes in the mammary gland of transgenic animals is one of the most cost-effective ways for the production of valuable recombinant therapeutic proteins. Among the transgenic species used so far, rabbits are good candidates for the expression of tens to hundreds of grams of complex proteins in the milk during lactation. The lactating mammary gland of rabbits has proven to be effective in the processing of complex proteins. In this work. the potential use of rabbits as bioreactors is discussed based on our results and the published data.

Role of hemodynamic alterations in the partial protection afforded by uninephrectomy against glycerol-induced acute renal failure in rats

Systemic and renal hemodynamics and body fluid volumes were evaluated in 48-hour uninephrectomized (UNX) and sham-operated (SO) rats, 3 h after glycerol-induced acute renal failure (ARF). UNX rats showed a 20% increase in cardiac output (CO) and renal blood flow (RBF) and a 20% decrease in total peripheric resistance (TPR) and renal vascular resistance (RVR) with respect to the control rats. There was no difference in body fluid volumes. 3 h after ARF induction UNX rats showed a minor decrease in RBF and GFR and a minor increase in RVR when compared with the control rats. CO decreased to similar levels in both UNX and SO rats. Mean arterial pressure and TPR increases were observed in UNX and SO rats but these increases were higher in the UNX than in the SO rats. Plasma and extracellular volumes were reduced in both groups of rats. The partial protection afforded by the renal mass reduction against the glycerol-induced ARF seem to be explained by the minor decrease in RBF and the lesser increase in RVR exhibited by the UNX rats after ARF induction.

Use of F1 progeny of Holstein × Zebu cross cattle as oocyte donors for in vitro embryo production and gene microinjection

This study was designed to determine the possibility of using F1 crossbreed cattle (HolsteinxZebu) as donors of oocytes for in vitro fertilization (IVF) and for pronuclear gene microinjection into in vitro-produced embryos. In the first part of the experiment oocytes from Bos taurus (Holstein), Bos indicus (Zebu) and F1 crossbred Bos taurusxBos indicus (HolsteinxZebu) genotypes were inseminated with Bos taurus (Holstein) semen and were allocated for in vitro embryo production using conventional IVF procedures. No differences were observed on the in vitro maturation (IVM) rates between breeds (HolsteinxHolstein:85%, ZebuxHolstein:84% and ZebuxHolsteinxHolstein:88%). Holstein cows yielded the highest number of cumulus oocyte complexes (6.8 per ovary) for in vitro maturation, differing (P<0.05) from ZebuxHolstein and ZebuxHolsteinxHolstein F1 by 5.1 and 5.8, respectively. However, the Holstein breed also yielded the lowest percentage of cleavage (45.1 vs 71.9% for ZebuxHolstein and 65.1% for ZebuxHolsteinxHolstein). Of the 3 genotypes, the hybrid F1 breed was the most efficient source of oocytes for the production of embryos capable of reaching morulae and blastocyst stages (76/250; P<0.001). In the second part of the study, 599 oocytes from the F1 breed were fertilized in vitro, 1 group of 150 oocytes was used for the determination of the optimal pronuclear visualization period. The highest number of oocytes with 2 pronuclei was observed between 24 to 28 h after IVF (27 to 42%). The remaining 399 oocytes were microinjected with a gene construct bearing the bacterial lacZ gene as the reporter for gene expression. Survival of embryos to microinjection was 73.8%, and 45.5% of them (50/110) cleaved in culture. Of the microinjected embryos, 1 out of 50 showed beta-galactosidase activity. These findings indicate that a tropical crossbreed of cattle (ZebuxHolsteinxHolstein) can be used as a source of oocytes for IVF programs and gene microinjection studies.

The cholecystokinin analogues JMV-180 and CCK-8 stimulate phospholipase C through the same binding site of CCK(A) receptor in rat pancreatic acini

1. This study was designed to address the controversy related to the involvement of phospholipase C in the signalling pathway linked to CCK(A) receptor stimulation by the cholecystokinin analogue JMV-180, a full agonist for amylase release, in rat pancreatic acini. 2. JMV-180 was shown to stimulate phospholipase C by measuring the incorporation of [(32)P]-orthophosphoric acid ([(32)P]-Pi) into phosphatidic acid (PtdOH) and phosphatidylinositol (PtdIns). Both responses elicited by JMV-180 were time and concentration dependent. Maximal effects elicited by JMV-180 were 39.08+/-0.72 and 8.02+/-0.40% for the labelling of [(32)P]-PtdIns and [(32)P]-PtdOH, respectively, as compared to the maximal effects of CCK-8, a full agonist of the CCK(A) receptor. 3. [(32)P]-Pi incorporation into PtdOH and PtdIns was sensitive to lithium, demonstrating that both responses are a consequence of phospholipase C activation. However, since lithium blocks the phosphoinositide cycle by an uncompetitive mechanism, its effect was only apparent at high concentrations of CCK-8 (>10 pM), which elicited stimuli above 20 and 60% of the maximal [(32)P]-PtdOH and [(32)P]-PtdIns labelling, respectively. 4. JMV-180 inhibited the incorporation of [(32)P]-Pi into PtdOH and PtdIns as stimulated by CCK-8, down to its own maximal effect. The estimated IC(50) values for the inhibition curves were not significantly different from those calculated assuming the same single binding site for both agonists. These results indicated that the well established role of JMV-180 as a partial agonist for CCK(A) receptor-linked signalling responses, also applies for the stimulation of phospholipase C. 5. The comparison of CCK-8 and JMV-180 dose-response curves of amylase release to those of PtdIns and PtdOH labelling with [(32)P]-Pi showed the existence of an amplification mechanism between phospholipase C and amylase release for both agonists. 6. In conclusion, we show that JMV-180, as well as CCK-8, stimulate phospholipase C upon interaction with the same binding site at the CCK(A) receptor in rat pancreatic acini.

Cholecystokinin octapeptide CCK-8 and carbachol reduce [(32)P]orthophosphate labeling of phosphatidylcholine without modifying phospholipase D activity in rat pancreatic acini

We have studied phospholipase D activation in [(32)P]orthophosphoric acid-prelabeled rat pancreatic acini by measuring the formation of (32)P-phosphatidylalcohols as stimulated in the presence of ethanol or butanol. A small but significant and time-dependent basal accumulation of [(32)P]phosphatidylethanol and [(32)P]phosphatidylbutanol was detected, which was further stimulated by phorbol myristate acetate, orthovanadate and pervanadate. However, the secretagogues cholecystokinin octapeptide and carbachol did not enhance basal accumulation of (32)P-phosphatidylalcohol, yet they decreased [(32)P]phosphatidylcholine content and stimulated the generation of [(32)P]phosphatidic acid. Our results stress the need to examine the transphosphatidylation reaction as well as agonist effects on the synthesis of phosphatidylcholine in order to assess unambiguously phospholipase D activity.

An Autoimmune Haemolytic Anaemia Secondary to Ipilimumab Treatment

BACKGROUND

Melanoma is one of the fastest growing neoplasms worldwide. Treatment of metastatic disease has swiftly shifted in the last decade from generally ineffective chemotherapy regimens to highly effective targeted treatments or immunotherapy, with a range of side effects that differ completely from those of previous treatments for this disease.

CASE

We present a case of a 71-year-old man with diagnosis metastatic melanoma. This patient was treated with anti-CTLA-4 antibody ipilimumab. Despite minor skin toxicity, the regimen was well tolerated until he developed hemolytic anemia, an autoimmune side effect of ipilimumab. The treatment was withdrawn and steroids were administered until the issue was resolved.

CONCLUSION

Immunotherapy has become the standard of care for many tumors, and its side effects are completely different from those of chemotherapy, meaning that oncologists must be aware of this to avoid a potentially life-threatening situation and arrive at an early diagnosis and implement prompt treatment.Key words: anemia - autoimmune event - anti-CTLA-4.