Transient production of receptor-binding domain of SARS-CoV-2 in Nicotiana benthamiana plants induces specific antibodies in immunized mice

BACKGROUND

The COVID-19 pandemic caused by the SARS-CoV-2 coronavirus has currently affected millions of people around the world. To combat the rapid spread of COVID-19 there is an urgent need to implement technological platforms for the production of vaccines, drugs and diagnostic systems by the scientific community and pharmaceutical companies. The SARS-CoV-2 virus enters the cells by the interaction between the receptor-binding domain (RBD) present in the viral surface spike protein and its human receptor ACE2. The RBD protein is therefore considered as the target for potential subunit-based vaccines.

METHODS AND RESULTS

We evaluate the use of Nicotiana benthamiana plants as the host to transiently-producing recombinant RBD (RBDr) protein. The identity of the plant-produced RBDr was confirmed by immune assays and mass spectrometry. Immunogenicity was confirmed through the specific antibodies generated in all of the immunized mice compared to the PBS treated group.

CONCLUSIONS

In conclusions, the immunogenicity of the RBDr produced in N. benthamiana was confirmed. These findings support the use of plants as an antigen expression system for the rapid development of vaccine candidates.

Continuously Sheared Granular Matter Reproduces in Detail Seismicity Laws

We introduce a shear experiment that quantitatively reproduces the main laws of seismicity. By continuously and slowly shearing a compressed monolayer of disks in a ringlike geometry, our system delivers events of frictional failures with energies following a Gutenberg-Richter law. Moreover, foreshocks and aftershocks are described by Omori laws and interevent times also follow exactly the same distribution as real earthquakes, showing the existence of memory of past events. Other features of real earthquakes qualitatively reproduced in our system are both the existence of a quiescence preceding some main shocks, as well as magnitude correlations linked to large quakes. The key ingredient of the dynamics is the nature of the force network, governing the distribution of frictional thresholds.

High accumulation in tobacco seeds of hemagglutinin antigen from avian (H5N1) influenza

Tobacco seeds can be used as a cost effective system for production of recombinant vaccines. Avian influenza is an important respiratory pathogen that causes a high degree of mortality and becomes a serious threat for the poultry industry. A safe vaccine against avian flu produced at low cost could help to prevent future outbreaks. We have genetically engineered tobacco plants to express extracellular domain of hemagglutinin protein from H5N1 avian influenza virus as an inexpensive alternative for production purposes. Two regulatory sequences of seed storage protein genes from Phaseolus vulgaris L. were used to direct the expression, yielding 3.0 mg of the viral antigen per g of seeds. The production and stability of seed-produced recombinant HA protein was characterized by different molecular techniques. The aqueous extract of tobacco seed proteins was used for subcutaneous immunization of chickens, which developed antibodies that inhibited the agglutination of erythrocytes after the second application of the antigen. The feasibility of using tobacco seeds as a vaccine carrier is discussed.

Biofibre hair implant – impact on the quality of life

Body image refers to how we feel about our bodies. It does not refer to what we actually look like, but rather to our perceptions, opinions and ways of thinking about our appearance. How we feel about our appearance is part of our body image and self-image. The hair is a significant part of this image. The problem of alopecia affects both sexes and all ages with significant sequelae. Along with androgenetic alopecia, there are forms of alopecia of various origins: traumatic, surgical, pharmacological and others. Polyamide artificial hair implant (Biofibre®) is one of the current techniques used to treat this problem.

Revealing the structure of a granular medium through ballistic sound propagation

We study the propagation of sound through a bidimensional granular medium consisting of photoelastic disks, which are packed into different crystalline and disordered structures. Acoustic sensors placed at the boundaries of the system capture the acoustic signal produced by a local and well-controlled mechanical excitation. By compressing the system, we find that the speed of the ballistic part of the acoustic wave behaves as a power law of the applied force with both exponent and prefactor sensitive to the internal geometry of the contact network. This information, which we are able to link to the force-deformation relation of single grains under different contact geometries, provides enough information to reveal the structure of the granular medium.

High frequency monitoring reveals aftershocks in subcritical crack growth

By combining direct imaging and acoustic emission measurements, the subcritical propagation of a crack in a heterogeneous material is analyzed. Both methods show that the fracture proceeds through a succession of discrete events. However, the macroscopic opening of the fracture captured by the images results from the accumulation of more-elementary events detected by the acoustics. When the acoustic energy is cumulated over large time scales corresponding to the image acquisition rate, a similar statistics is recovered. High frequency acoustic monitoring reveals aftershocks responsible for a time scale dependent exponent of the power law energy distributions. On the contrary, direct imaging, which is unable to resolve these aftershocks, delivers a misleading exponent value.

Sound and light from fractures in scintillators

Prompted by intriguing events observed in certain particle-physics searches for rare events, we study light and acoustic emission simultaneously in some inorganic scintillators subject to mechanical stress. We observe mechanoluminescence in Bi4Ge3O12, CdWO4, and ZnWO4, in various mechanical configurations at room temperature and ambient pressure. We analyze the temporal and amplitude correlations between the light emission and the acoustic emission during fracture. A novel application of the precise energy calibration of Bi4Ge3O12 provided by radioactive sources allows us to deduce that the fraction of elastic energy converted to light is at least 3×10(-5).

Foraging at the edge of chaos: internal clock versus external forcing

Activity rhythms in animal groups arise both from external changes in the environment, as well as from internal group dynamics. These cycles are reminiscent of physical and chemical systems with quasiperiodic and even chaotic behavior resulting from "autocatalytic" mechanisms. We use nonlinear differential equations to model how the coupling between the self-excitatory interactions of individuals and external forcing can produce four different types of activity rhythms: quasiperiodic, chaotic, phase locked, and displaying over or under shooting. At the transition between quasiperiodic and chaotic regimes, activity cycles are asymmetrical, with rapid activity increases and slower decreases and a phase shift between external forcing and activity. We find similar activity patterns in ant colonies in response to varying temperature during the day. Thus foraging ants operate in a region of quasiperiodicity close to a cascade of transitions leading to chaos. The model suggests that a wide range of temporal structures and irregularities seen in the activity of animal and human groups might be accounted for by the coupling between collectively generated internal clocks and external forcings.

Experimental study of the effect of disorder on subcritical crack growth dynamics

The growth dynamics of a single crack in a heterogeneous material under subcritical loading is an intermittent process, and many features of this dynamics have been shown to agree with simple models of thermally activated rupture. In order to better understand the role of material heterogeneities in this process, we study the subcritical propagation of a crack in a sheet of paper in the presence of a distribution of small defects such as holes. The experimental data obtained for two different distributions of holes are discussed in the light of models that predict the slowing down of crack growth when the disorder in the material is increased; however, in contradiction with these theoretical predictions, the experiments result in longer lasting cracks in a more ordered scenario. We argue that this effect is specific to subcritical crack dynamics and that the weakest zones between holes at close distance to each other are responsible for both the acceleration of the crack dynamics and the slightly different roughness of the crack path.

Genomics and proteomics approaches to the study of cancer-stroma interactions

Background

The development and progression of cancer depend on its genetic characteristics as well as on the interactions with its microenvironment. Understanding these interactions may contribute to diagnostic and prognostic evaluations and to the development of new cancer therapies. Aiming to investigate potential mechanisms by which the tumor microenvironment might contribute to a cancer phenotype, we evaluated soluble paracrine factors produced by stromal and neoplastic cells which may influence proliferation and gene and protein expression.

Methods

The study was carried out on the epithelial cancer cell line (Hep-2) and fibroblasts isolated from a primary oral cancer. We combined a conditioned-medium technique with subtraction hybridization approach, quantitative PCR and proteomics, in order to evaluate gene and protein expression influenced by soluble paracrine factors produced by stromal and neoplastic cells.

Results

We observed that conditioned medium from fibroblast cultures (FCM) inhibited proliferation and induced apoptosis in Hep-2 cells. In neoplastic cells, 41 genes and 5 proteins exhibited changes in expression levels in response to FCM and, in fibroblasts, 17 genes and 2 proteins showed down-regulation in response to conditioned medium from Hep-2 cells (HCM). Nine genes were selected and the expression results of 6 down-regulated genes (ARID4A, CALR, GNB2L1, RNF10, SQSTM1, USP9X) were validated by real time PCR.

Conclusions

A significant and common denominator in the results was the potential induction of signaling changes associated with immune or inflammatory response in the absence of a specific protein.

Avalanche prediction in a self-organized pile of beads

It is a common belief that power-law distributed avalanches are inherently unpredictable. This idea affects phenomena as diverse as evolution, earthquakes, superconducting vortices, stock markets, etc., from atomic to social scales. It mainly comes from the concept of "self-organized criticality" (SOC), where criticality is interpreted in the way that, at any moment, any small avalanche can eventually cascade into a large event. Nevertheless, this work demonstrates experimentally the possibility of avalanche prediction in the classical paradigm of SOC: a pile of grains. By knowing the position of every grain in a two-dimensional pile, avalanches of moving grains follow a distinct power-law distribution. Large avalanches, although uncorrelated, are on average preceded by continuous, detectable variations in the internal structure of the pile that are monitored in order to achieve prediction.

High frequency of immature dendritic cells and altered in situ production of interleukin-4 and tumor necrosis factor-alpha in lung cancer

INTRODUCTION

Antigen-presenting cells, like dendritic cells (DCs) and macrophages, play a significant role in the induction of an immune response and an imbalance in the proportion of macrophages, immature and mature DCs within the tumor could affect significantly the immune response to cancer. DCs and macrophages can differentiate from monocytes, depending on the milieu, where cytokines, like interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce DC differentiation and tumor necrosis factor (TNF)-alpha induce DC maturation. Thus, the aim of this work was to analyze by immunohistochemistry the presence of DCs (S100+ or CD1a+), macrophages (CD68+), IL-4 and TNF-alpha within the microenvironment of primary lung carcinomas.

RESULTS

Higher frequencies of both immature DCs and macrophages were detected in the tumor-affected lung, when compared to the non-affected lung. Also, TNF-alpha-positive cells were more frequent, while IL-4-positive cells were less frequent in neoplastic tissues. This decreased frequency of mature DCs within the tumor was further confirmed by the lower frequency of CD14-CD80+ cells in cell suspensions obtained from the same lung tissues analyzed by flow cytometry.

CONCLUSION

These data are discussed and interpreted as the result of an environment that does not oppose monocyte differentiation into DCs, but that could impair DC maturation, thus affecting the induction of effective immune responses against the tumor.

Uphill solitary waves in granular flows

We have experimentally observed uphill solitary waves in the surface flow on a granular material. A heap is constructed by injecting sand between two vertical glass plates separated by a distance much larger than the average grain size, with an open boundary. As the heap reaches the open boundary, solitary fluctuations appear on the flowing layer and move "up the hill" (i.e., against the direction of the flow). We explain the phenomenon in the context of stop-and-go traffic models.

Quasiperiodic events in an earthquake model

We introduce a modification of the Olami-Feder-Christensen earthquake model [Phys. Rev. Lett. 68, 1244 (1992)10.1103/PhysRevLett.68.1244] in order to improve the resemblence with the Burridge-Knopoff mechanical model and with possible laboratory experiments. A constant and finite force continually drives the system, resulting in instantaneous relaxations. Dynamical disorder is added to the thresholds following a narrow distribution. We find quasiperiodic behavior in the avalanche time series with a period proportional to the degree of dissipation of the system. Periodicity is not as robust as criticality when the threshold force distribution widens, or when an increasing noise is introduced in the values of the dissipation.

The role of tropomyosin-related kinase receptors in neurotrophin-induced rapid eye movement sleep in the cat

The microinjection of nerve growth factor and neurotrophin-3 into the rostro-dorsal pontine tegmentum of the cat evokes a state that is comparable to naturally-occurring rapid eye movement sleep. Using two experimental paradigms, we tested the hypothesis that neurotrophin high-affinity receptors (trkA and trkC, tropomyosin-related kinase A and C, respectively) mediate this effect. First, trk and fos immunohistochemistry were combined to determine whether tyrosine kinase receptor-containing neurons in the dorsal pontine tegmentum are active in cats that exhibit long-lasting periods of rapid eye movement sleep following the local microinjection of nerve growth factor. During approximately two hours of recording, nerve growth factor-treated cats spent 59.8% of the time in a rapid eye movement sleep-like state; vehicle-injected (control) animals remained in quiet wakefulness and non-rapid eye movement sleep. Whereas control and nerve growth factor-treated cats exhibited a similar mean number of trkA- and trkC-immunoreactive neurons in the dorsal pontine tegmentum, the number of trkA- and trkC-immunoreactive neurons that expressed Fos, i.e. double-labeled cells that are presumably activated, was significantly larger in cats that were injected with nerve growth factor. Axon terminals contained tyrosine kinase receptor immunoreactivity in this region; many were apposed to Fos-immunoreactive neurons. In addition, patterns of tyrosine kinase receptor and Fos immunoreactivity similar to those observed in nerve growth factor-injected cats were present, in conjunction with long-lasting rapid eye movement sleep, following the microinjection of carbachol into the dorsal pons. In a second series of studies, nerve growth factor or neurotrophin-3 was injected alone or after K-252a, a blocker of tyrosine kinase receptors, into the rostro-dorsal pontine tegmentum. Nerve growth factor or neurotrophin-3 alone produced, with a mean latency of 4 min, a rapid eye movement sleep-like state. However, neurotrophin injections preceded by K-252a were not effective in inducing rapid eye movement sleep. These results indicate that the activation of trkA and trkC receptors in neurons in the pontine tegmentum is responsible, at least in part, for the rapid eye movement sleep-inducing effect of nerve growth factor and neurotrophin-3. Furthermore, the data suggest that these neurotrophins are capable of acting both pre- and postsynaptically to activate pontine neurons that are involved in the generation of rapid eye movement sleep.

Symmetry Breaking in Escaping Ants

The phenomenon of herding is a very general feature of the collective behavior of many species in panic conditions, including humans. It has been predicted theoretically that panic-induced herding in individuals confined to a room can produce a nonsymmetrical use of two identical exit doors. Here we demonstrate the existence of that phenomenon in experiments, using ants as a model of pedestrians. We show that ants confined to a cell with two symmetrically located exits use both exits in approximately equal proportions to abandon it in normal conditions but prefer one of the exits if panic is created by adding a repellent fluid. In addition, we are able to reproduce the observed escape dynamics in detail using a modification of a previous theoretical model that includes herding associated with a panic parameter as a central ingredient. Our experimental results, combined with theoretical models, suggest that some features of the collective behavior of humans and ants can be quite similar when escaping under panic.

Sandpile formation by revolving rivers

Experimental observation of a new mechanism of sandpile formation is reported. As a steady stream of dry sand is poured onto a horizontal surface, a pile forms which has a thin river of sand on one side flowing from the apex of the pile to the edge of its base. The river rotates about the pile, depositing a new layer of sand with each revolution, thereby causing the pile to grow. For small piles the river is steady and the pile formed is smooth. For larger piles, the river becomes intermittent and the surface of the pile becomes undulating. The essential features of the system that produce the phenomenon are discussed, and the robustness of the phenomena is demonstrated with experiments using different boundary conditions and sands.

Avalanches in one-dimensional piles with different types of bases

We perform a systematic experimental study of the influence of the type of base on the avalanche dynamics of slowly driven 1D ball piles. The control of base details allows us to explore a wide spectrum of pile structures and dynamics. The scaling properties of the observed avalanche distributions suggest that self-organized critical behavior is approached as the "base-induced" disorder at the pile profile increases.

Interrater reliability of plaque morphology classification in patients with severe carotid artery stenosis

OBJECTIVE

Ultrasonographic assessment of carotid artery plaque morphology is widely used to identify patients at high risk for stroke. However, the reliability of plaque analysis in high-grade stenosis is uncertain. We determined the interrater reliability of sonographic plaque morphology analysis in patients with severe carotid artery stenosis.

MATERIALS AND METHODS

Duplex Doppler was performed on 114 patients with 80-99% stenosis of the internal carotid artery using a Siemens Quantum 2000 D with a handheld 7.5 MHz transducer. B-mode pictures with and without color coding were printed on a Sony color video printer UP-5000 W. Three raters independently evaluated plaque echolucency, heterogeneity, calcification, and surface structure. Interrater agreement was calculated by a jackknife procedure generating kappa values and two-sided 95% confidence intervals.

RESULTS

Kappa values and 95% confidence intervals were 0.05 (-0.07 to 0.16) for plaque surface structure, 0.15 (0.02 to 0.28) for plaque heterogeneity, 0.18 (0.09 to 0.29) for plaque echogenicity, and 0.29 (0.19 to 0.39) for plaque calcification. The upper bounds of all of the confidence intervals were below the 0.40 level suggested for minimal reliability.

CONCLUSION

The low interrater agreement indicated that unaided visual assessment of static B-mode pictures to assess plaque morphology in patients with severe carotid artery stenosis is not reliable. Other evaluation procedures and standardized criteria, as yet undeveloped, are needed to improve reliability.

Euthanasia and relief of suffering: attitudes of medical students

Medical students, from the first, second and third year classes of the University of Puerto Rico School of Medicine, answered a questionnaire which included testing knowledge and attitudes about euthanasia and the relief of suffering. More than 60% of each class participated, a total of two hundred. Ninety three percent of the students knew the definition of euthanasia but 50 percent could not tell the difference between active and passive euthanasia. Students in the first year were better oriented than their counterparts in the third year (58 percent versus 44 percent). Seventy percent of the 100 students who could differentiate between active and passive euthanasia thought that active euthanasia should not be considered murder, but 69 percent were cognizant it was so considered in Puerto Rico. Eighty-three percent of first year students but only 61 percent of third year students thought that physicians should alleviate suffering of terminally ill patients. Medical schools should provide a serious, unprejudiced and complete discussion of euthanasia and other life and death issues in their curricula. A humane orientation of medical students should be given as much emphasis as other aspects of professional training.

Arsenic increased lipid peroxidation in rat tissues by a mechanism independent of glutathione levels

The role of lipid peroxidation in the mechanism of arsenic toxicity was investigated in female rats pretreated with N-acetylcysteine (NAC, a glutathione [GSH] inducer) or with buthionine sulfoximine (BSO, a GSH depletor). Rats were challenged with sodium arsenite, and sacrificed 1 hr after this treatment. Results showed that arsenic decreased GSH levels and increased lipid peroxidation in liver, kidney, and heart, with a larger effect at 18.2 mg/kg than at 14.8 mg/kg for lipid peroxidation induction. In the liver of rats treated with arsenic, pretreatment with NAC increased the levels of GSH and decreased lipid peroxidation. In kidney and heart, NAC pretreatment protected the tissues against arsenic-induced depletion of GSH levels, but the same degree of protection was not found for lipid peroxidation induction. In its turn, BSO had an additive effect with arsenic in lowering the levels of GSH in the liver and kidney, but an inverse correlation between GSH levels and lipid peroxidation was found only in liver. Arsenic content in tissues of rats pretreated with NAC was lower than in rats treated only with arsenic. In rats with depleted levels of GSH (BSO-pretreated rats), a shift in arsenic tissue distribution was found, with higher levels in skin and lower levels in kidney. A clear tendency for a positive correlation between arsenic concentration and lipid peroxidation levels was found in liver, kidney, and heart.

Major histocompatibility complex class II alleles and haplotypes and blood groups of four Amerindian tribes of northern Colombia

MHC class II alleles and haplotypes were determined from unrelated individuals and families of the Arhuaco (n = 107), Kogi (n = 42), Arsario (n = 18), and Wayú (n = 88) tribes located in the northern part of Colombia. Class II DRB, DQA1, and DQB1 alleles were determined by PCR-SSO and PCR-RFLP based methods. Four haplotypes, [DRB1*0407, DRB4*0101, DQA1*03, DQB1*0302]; [DRB1*0403, DRB4*0101, DQA1*03, DQB1*0302]; [DRB1*1402/1406, DRB3*0101, DQA1*0501, DQB1*0301]; and [DRB1*0802, DQA1*0401, DQB1*0402], were observed among these four tribes. In addition to these haplotypes, the Wayú Indians showed a frequency of 21.3% for the [DRB1*1602, DRB5*02, DQA1*0501, DQB1*0301] haplotype, 13.1% for the [DRB1*0411, DRB4*0101, DQA1*03, DQB1*0302] haplotype, and 8.1% for the [DRB1*0411, DRB4*0101, DQA1*03, DQB1*0402] haplotype. Red cell antigen typing was used to calculate genetic admixture. The Kogi and Arsario showed no genetic admixture while the Arhuaco tribe showed admixture with genes of African origin and the Wayú showed admixture with Caucasians as well as genes of African origin. These findings were confirmed by the MHC class II allele and haplotype data obtained, as alleles and haplotypes of Caucasian and African origin were detected in the Wayú and Arhuaco and not in the Kogi or Arsario. These studies will be important in disease association and transplantation studies for Amerindian and colombian populations and for correlating genetic traits with the anthropologic and linguistic data available in order to better understand the Amerindian populations.

Lipoprotein (a) and other risk factors in children with insulin-dependent diabetes mellitus and children without diabetes

AIMS

To study serum Lp(a) levels and other metabolic cardiovascular risk factors in children with Type 1 diabetes mellitus (DM) compared to sex and age matched nondiabetic children. The correlation of Lp(a) serum levels and other lipid parameters with HbA1c concentrations in diabetic children was investigated.

DESIGN

Transversal observational study.

TARGET POPULATION

36 C-peptide negative Type 1 DM children without microalbuminuria and no macromicrovascular or neurological complications, aged 8 to 15 years; 17 boys, 19 girls. Mean duration of Type 1 DM was 4.99 +/- 3.04 years, daily insulin need were 32.79 +/- 12.64 Units. 41 healthy children with no family history of DM, aged from 8 to 15 years, 26 boys, 15 girls, were studied in parallel as the control group.

METHODS

Serum total cholesterol (TC) and triglycerides (TG) were assayed by enzymatic methods, high-density lipoprotein (HDL) cholesterol by enzymatic method after precipitation of very-low-density (VLDL) and low-density lipoprotein (LDL) fractions. The LDL fractions was estimated after serum precipitation as the difference between total cholesterol and supernatant cholesterol concentrations. Apo-AI, apo-AII and apo-B were measured by radial immunodiffusion assays. Serum Lp(a) was measured by monoclonal anti-Lp(a) antibody (ELISA) method and whole blood glycosylated hemoglobin A1c (HbA1c) by high resolution liquid chromatography.

RESULTS

HbA1c concentration in diabetic children was 7.51 +/- 54% vs 4.16 +/- 0.35% in non diabetic children. Lp(a) serum levels did not significantly differ among both groups (25 +/- 22 mg/dl in diabetics subjects, 22 +/- 22 mg/dl in controls). Significant correlation was found between HbA1c levels and each of TC, LDL and TG serum concentrations in the diabetic group. Lp(a) levels were correlated with glycated hemoglobin in the whole diabetic group. But, in the 2 patients with the poorest metabolic control (HbA1c 10.5%) were excluded, the correlation disappeared.

CONCLUSIONS

In 36 children aged 5-15 years with uncomplicated Type 1 DM lasting less than 15 years, Lp(a) serum levels did not differ from age-matched controls but highest Lp(a) values were associated with poorest metabolic control.

Lipoprotein (a) and other risk factors in children with insulin-dependent diabetes mellitus and children without diabetes

AIMS

To study serum Lp (a) levels and other metabolic cardiovascular risk factors in children with type 1 diabetes mellitus (DM) as compared to sex and age matched nondiabetic children. The correlation of Lp (a) serum levels and other lipid parameters with HbA1c concentration in diabetic children was investigated.

DESIGN

Transversal observational study.

TARGET POPULATION

36 C-peptide negative Type 1 diabetic children without microalbuminuria and no macromicrovascular nor neurological complications, aged 8 to 15 years; 17 boys, 19 girls. Mean duration of Type 1 diabetes was 4.99 +/- 3.04 years, daily insulin needs 32.79 +/- 12.64 Units. 41 healthy children with no family history of diabetes mellitus, aged 8 to 15 years, 26 boys, 15 girls, were studied in parallel as the control group.

METHODS

Serum total cholesterol and triglycerides were assayed by enzymatic methods, High-density lipoprotein (HDL) cholesterol by enzymatic method after precipitation of very-low-density (VLDL) and low-density lipoprotein (LDL) fractions. The LDL fraction was estimated after serum precipitation as the difference between total cholesterol and supernatant cholesterol concentrations. Apo-AI, apoA-II and apo-B were measured by radial immunodiffusion assays. Serum Lp(a) was measured by a monoclonal anti-Lp(a) antibody (ELISA) method and whole blood glycosylated hemoglobin A1c (HbA1c) by high resolution liquid chromatography.

RESULTS

HbA1c concentration in diabetic children was 7.51 +/- 1.54% vs 4.16 +/- 0.35% in nondiabetic children. Lp(a) serum levels did not significantly differ among both groups (25 +/- 22 mg/dl in diabetics; 22 +/- 22 mg/dl in controls). Significant correlation was found between HbA1c levels and each of TC, LDL and TG serum concentrations in the diabetic group. Lp (a) levels were only correlated with glycated hemoglobin in the two patients showing the highest levels of HbA1c; in the diabetic group: HbA1c 10.9 and 11.5%.

CONCLUSIONS

In 36 children aged 8-15 years with uncomplicated Type 1 diabetes for less than 15 years duration, Lp (a) serum levels were positively correlated with HbA1c only in two of them showing the poorest metabolic control.

[HIV infection and AIDS: neuropsychiatric and neuropsychological aspects]

The progressive confirmation of the neurotropic character of HIV, in juxtaposition to the recognition of AIDS dementia complex as an important central nervous system clinical manifestation, have engendered a greater interest in this phenomena. Consequently, a more precise description of the behavioral and mental aspects of this infection have evolved. This article has two purposes, to discuss the AIDS dementia complex concept and secondly, to review the neuropsychiatric and neuropsychological aspects of infection by HIV and AIDS, as it pertains to adult patients.

Cost-effectiveness analysis of the treatment of end-stage renal disease in Brazil

Cost-effectiveness analysis compared four treatments of end-stage renal disease in Brazil: continuous ambulatory peritoneal dialysis (CAPD), in-center hemodialysis (HD), cadaver donor transplantation (CD-Tx), and living related donor transplantation (LR-Tx). After 2 years, the costs per year of survival were CAPD, $12,134; HD, $10,065; CD-Tx, $6,978; and LR-Tx, $3,022. The HD cost was lower than CAPD partially because of the reuse of hemodialyzers in Brazil. Although less cost-effective, both dialysis treatments yielded more years of survival after 2 years. This analysis reveals a trade-off between cost per year of survival and years of survival.

Staphylococcus aureus skin carriage and development of peritonitis in patients on continuous ambulatory peritoneal dialysis

We conducted a 15-month prospective study to investigate the skin carriage of Staphylococcus aureus and the development of peritonitis in 43 patients undergoing continuous ambulatory peritoneal dialysis (CAPD). Sixteen of 43 patients (37%) were chronic carriers of S. aureus in the anterior nares and/or in the exit-site of the catheter; 12 patients (28%) were intermittent carriers, and 15 (35%) were noncarriers. Fifty episodes of peritonitis occurred during a total of 422 patient-months of observation. S. aureus was responsible for 16 episodes of peritonitis diagnosed in 15 patients. All episodes of S. aureus peritonitis occurred in chronic and intermittent carriers. Phage typing was performed on isolates from 8 patients with S. aureus peritonitis, and they were found to have the same phage type as that previously carried in the skin. We conclude that CAPD patients who are chronic or intermittent carriers of S. aureus are at higher risk of development of peritonitis than noncarriers.

Elevated NK sensitivity of Raji cells carrying acceptor-bound C3 fragments

The majority of cell lines derived from Burkitt lymphomas carry CR2 on their plasma membrane cell lines of haematopoietic origin can activate C3 present in human serum through the alternative pathway. However, only the lines that carry CR2 were shown to bind C3 fragments. This bond can be either fixation to acceptor sites or attachment to the CR. Our studies with Raji cells showed that when the possibility for the covalent acceptor bond was eliminated by using methylamine (MA)- or zymosan-treated serum, considerably lower amounts of C3 were bound. In the zymosan-treated serum C3 fragments are present that can bind to receptors but their capacity for acceptor bond is absent. These results indicate that when Raji cell are incubated in human serum some of the generated C3 fragments are bound to acceptors and a lower proportion through the specific interaction with complement receptors. Pretreatment of the CR2 carrying cell lines with human serum elevated their sensitivity to the lytic effect of human blood lymphocytes. We showed in this work that MA-treated serum did not induce this elevation. Zymosan-treated serum under conditions that excluded activation of the residual native C3 molecules, i.e., in the presence of EDTA, did not have the enhancing effect either. These results suggest that the increased lytic efficiency imposed by human serum was due to cleavage of C3 molecules by Raji and fixation of the C3 fragments by acceptor sites. Natural killer cells carry CR3; therefore it is likely that the attached C3 fragments bind also to the effector cells. The C3 molecules could elevate thereby the avidity between the target and the lytic lymphocytes. The observation that C3 fragments are not bound to the surface of CR2 negative lines in spite of their capacity to activate C3 suggests that the receptor molecule is either involved in the activation and/or serves also as an acceptor.

Yellow-brown (Hamazaki-Wesenberg) bodies mimicking fungal yeasts

We describe herein two cases in which yellow-brown (Y-B) bodies, also known as Hamazaki-Wesenberg bodies, were encountered in lymph nodes and initially misinterpreted as fungal organisms. Because of occasional "budding" forms and positive staining with "screening" fungal stains (Grocott methenamine silver and periodic acid-Schiff), Y-B bodies may closely resemble budding yeast fungi. We describe the characteristic light microscopic and ultrastructural morphologic features of Y-B bodies, and their histochemical staining reactions, and emphasize the value of the Fontana-Masson silver stain for recognition and identification of these bodies.

[Chemical evaluation and determination of the nutritive value of a variety of Opaque-2 corn in the initial diet of broilers]

Chemical and amino acidic composition of Opaque-2 corn, cultivar CIMMYT-TL 81-A (Hungarian compound) locally produced were determined. In addition, the productive performance of broiler chicks fed Opaque-2 corn or normal corn (Pioneer) for the first 28 days of age was evaluated. The chemical and amino acid content results obtained for the Opaque-2 corn studied, compared well ranges previously reported. The productive performance at the end of the experiment was similar between the two treatments assayed.

Effects of a specific inhibitor of the vascular action of vasopressin in humans

Experimental evidence indicates that arginine vasopressin (AVP) may contribute to the rise of blood pressure (BP) in hypertension induced by renal failure and sodium overload. We studied the AVP inhibitor [1-(B-mercapto-B,B-cyclopentamethylenepropionic acid)-2-(O-methyl)tyrosine] AVP in 12 normal and seven hypertensive subjects with end-stage renal disease. To test the agent's capacity to block the pressor action of exogenous AVP In humans, we constructed a dose-response curve with AVP doses of 1 to 20 mU/kg, raising BP by up to 30 mm Hg. Subsequently, five volunteers receive intravenous (i.v.) doses of 0.1 mg, and five volunteers received 0.5 mg of the inhibitor. The dose-response curve was then repeated with AVP doses up to 200 mU/kg. Both doses of the inhibitor shifted the curve to the right and downward, with the BP response to 20 mU/kg AVP being inhibited by 23% and 80% respectively. The duration of action of the compound was tested in two additional subjects, and was found to be over 3 hours. We then tested the compound in seven hypertensive patients with end-stage renal failure. Two days before dialysis, patients received a 150 mEq/day Na diet. After an additional Na load of 180 mEq via i.v. saline over 3 hours under constant BP and ECG monitoring, they received an i.v. bolus of 0.5 mg AVP inhibitor. A moderate BP fall occurred in five patients; it was maximal at 45 to 60 minutes and returned to baseline by 70 to 90 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

[Monozygotic twins with a minimal cerebral dysfunction syndrome]

Two monozygotic boys, 5 years and 5 months old, with a normal IQ, whose father had suffered from stuttering, language retardation and dyslexia showed a minimal brain dysfunction syndrome. A genetic etiology is likely in these patients. Other etiological factors remain obviously possible in other patients.

A progressive syndrome of autism, dementia, ataxia, and loss of purposeful hand use in girls: Rett's syndrome: report of 35 cases

Thirty-five patients, exclusively girls, from three countries had a uniform and striking progressive encephalopathy. After normal general and psychomotor development up to the age of 7 to 18 months, developmental stagnation occurred, followed by rapid deterioration of higher brain functions. Within one-and-a-half years this deterioration led to severe dementia, autism, loss of purposeful use of the hands, jerky truncal ataxia, and acquired microcephaly. The destructive stage was followed by apparent stability lasting through decades. Additional insidious neurological abnormalities supervened, mainly spastic parapareses, vasomotor disturbances of the lower limbs, and epilepsy. Prior extensive laboratory investigations have not revealed the cause. The condition is similar to a virtually overlooked syndrome described by Rett in the German literature. The exclusive involvement of females, correlated with findings in family data analyses, suggests a dominant mutation on one X chromosome that results in affected girls and nonviable male hemizygous conceptuses.

The incidence and prevention of folate deficiency in a pregnant clinic population

Non-anemic women attending a public antenatal clinic were given, daily, a multivitamin tablet containing 78 mg. of elemental iron. The follow-up studies included an analysis of their diets. A total of 311 patients were included, of which one group received a supplement of 0.5 mg. folic acid and 0.005 mg. vitamin B(12). The incidence of megaloblastic bone marrow change in the unsupplemented group was 26% and of low blood folates approximately 50%. The incidence of megaloblastic changes was sharply reduced in the supplemented group and the blood folates were elevated to supranormal levels, indicating that the dose of folic acid used may have been above the minimal requirement. Formiminoglutamic acid (FIGLU) excretion could not be correlated with other parameters of folate deficiency. Neutrophil lobe counts did not relate to megaloblastic changes or low folate levels unless there was more than 5% hypersegmentation. The dietary intake was suboptimal in total calories, iron and food folate.