Mutations in Rhipicephalus microplus GABA gated chloride channel gene associated with fipronil resistance.

The tropical cattle tick, Rhipicephalus microplus, is one of the most damaging parasites that affects cattle in tropical and subtropical regions in the world. Tick resistance to acaricides is dispersed worldwide and a number of associated mutations in target site genes have been described. Phenylpyrazole (e.g. fipronil) and cyclodiene (e.g. lindane, dieldrin) insecticides both have the same mode of action blocking the GABA-gated chloride channel encoded by the GABA-Cl gene. A conserved mutation, rdl (resistance to dieldrin) is found across a number of arthropods resistant to cyclodienes and phenylpyrazoles. In ticks, the mutation T290 L, was identified in the second transmembrane (TM2) domain of the GABA-gated chloride channel of Australian cattle tick populations that are resistant to dieldrin. Recently, cross-resistance between fipronil and lindane was reported in R. microplus populations obtained from Uruguay and Brazil. The objective of the present study was to identify mutations in the GABA-Cl gene associated with fipronil resistance. Genomic DNA was obtained from engorged females from fipronil-susceptible and resistant populations sampled from Uruguay and Brazil (n = 166). Initially, it was searched the T290 L mutation described in Australia; however, this mutation was not detected in individuals from resistant populations from either country. The sequencing of a fragment of the GABA-Cl gene revealed nucleotide polymorphisms in fipronil- and lindane-resistant ticks in two populations from Uruguay and five from Brazil. Five amino acid substitutions were present in the resistant strains. Two different substitutions were found in an alanine residue (A286S and A286 L) that is homolog to rdl mutations in fipronil-resistant individuals of other arthropod species. Four other amino acid substitutions (S281 T, V317I, T328 A and A329S) were present in some resistant strains, always with the mutation A286S. This is the first documentation of mutations in the GABA-Cl gene associated with fipronil-resistant in R. microplus.

[Resident of emergency attitude towards patients-physician relationship at the Hospital de Clínicas- Asunción, Paraguay]. / Actitud de residentes de urgencias hacia la relación médico-paciente en el Hospital de Clínicas- Asunción, Paraguay.

INTRODUCTION: The doctor-patient relationship is reaching great importance in recent times, is highlighted their importance in areas as varied as satisfaction, compliance, perception of professional competence, the frequency of legal issues relating to malpractice and even the prognosis of the disease or the general health of the patient. OBJECTIVE: To evaluate the doctor-patient relationship from the point of view of residents of emergency unit. METHODS: An observational, descriptive study. The sample consisted of 36 doctors from different areas of the Emergency Rooms of the Hospital de Clínicas- Asunción, Paraguay. The patient-physician relationship was evaluated using an instrument developed by RA Chavarria-Islas et al. with four indicators: Respect, Information, Consent and Dedication. RESULTS: 69.4% of residents have a regular patient-physician relationship; despite the 2.78% has a good relationship, 25% bad relationship and 2.78% a very bad relationship. CONCLUSION: Gaps in doctor-patient relationship were found in this study.. It is interesting to invest greater efforts to enhance the doctor-patient relationship as one of the edges to improve health care, which is vital in emergency care.

Se estudiaron retrospectivamente pacientes con diagnóstico de lupus eritematoso sistémico (LES) de acuerdo a criterios ACR 1982, con nefritis lúpica (NL) durante el período comprendido desde 2005 al 2012 y que fueran sometidos a una biopsia renal repetida. El número total de pacientes con NL atendidos fue de 120, de los cuales 18 (15%) pacientes fueron sometidos a biopsia renal repetida, 18 con 2 biopsias renales y 6 con 3 biopsias. 3 (16,7%) de los pacientes fueron fumadores; 1 (5,6%) poseía antecedentes de DBT previa, 2 (11,1%) poseían antecedentes de HTA; y 3 (16,7%) pacientes tenían obesidad previa. El tiempo de diagnóstico de LES al momento del estudio fue de 96 meses ± 15; el tiempo transcurrido entre la 1° y la 2° biopsia fue de 45 ± 11 meses y el tiempo entre la 2° y 3° biopsia fue de 56 ± 12 meses. Las indicaciones de la biopsia repetida fueron proteinuria en 10 biopsias (41,6%); proteinuria con alteración de la función renal en 2 biopsias (8,3%); proteinuria con sedimento patológico en 8 biopsias (33,3%); y proteinuria con sedimento patológico y alteración de la función renal en 4 biopsias (16,6%). Los cambios histológicos más frecuentes encontrados entre las primeras y las biopsias repetidas fueron: de clase IV a clase III: 2 (8,2%); clase IV a clase IV: 8 (33,3%), clase IV a clase III+V: 2 (8,2%); clase IV a clase IV+V: 3 (12,5%); clase IV a clase V: 2 (8,2%). Los cambios en las biopsias de NL proliferativas con índices de actividad y cronicidad (A/C) fueron: de A a A/C: 7 (29,1%), A/C a A/C: 7 (29,1%). La intensidad de la terapia inmunosupresora aumentó en 79,1%, se mantuvo el tratamiento inmunosupresor en 16.6%. Con respecto al cambio de medicación 7 (20%) pacientes recibieron Ciclofosfamida 1 gr cada 30 días, 9 (26%) Ciclofosfamida 500 mg cada 15 días, 8 (23%) tratamiento de reinducción con Micofenolato mofetil; Rituximab 8 (23%); y 3 (8%) Ciclosporina A. El tratamiento de mantenimiento se realizó con micofenolato mofetil en 23 casos (55%); con azatioprina en 11 (26%) casos; ciclosporina en 3 (7%) oportunidades y rituximab en 5 (12%). En todos los casos se utilizó hidroxicloroquina.

Cross-resistance between fipronil and lindane in Rhipicephalus (Boophilus) microplus.

The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), is one of the most damaging parasites of cattle in tropical and subtropical regions. Several chemical groups have been used for its control, including cyclodienes (lindane and dieldrin). In Uruguay and Brazil these products were used at the beginning of the 1960s and during a few years. Fipronil and lindane act on the same target site. In both countries, southern cattle tick resistance to fipronil has sometimes developed quickly after only a few acaricide treatments (three to seven). The objective of the present study was to determine cross-resistance between fipronil and lindane in southern cattle ticks from Uruguay and Brazil. Initially, the FAO's (Food and Agricultural Organization) larval packet test with lindane was applied to a fipronil-resistant strain and to susceptible field populations. Mozo and POA strains were used as the susceptible controls. A larval immersion test was used to assess fipronil toxicity. Of fifteen fipronil-resistant field populations that were tested with lindane, eleven were lindane-resistant and three were susceptible. The last three populations had incipient resistance to fipronil. Finally, cross-resistance between fipronil and lindane in the southern cattle tick is reported in this study for the first time.

X-linked congenital ptosis and associated intellectual disability, short stature, microcephaly, cleft palate, digital and genital abnormalities define novel Xq25q26 duplication syndrome.

Submicroscopic duplications along the long arm of the X-chromosome with known phenotypic consequences are relatively rare events. The clinical features resulting from such duplications are various, though they often include intellectual disability, microcephaly, short stature, hypotonia, hypogonadism and feeding difficulties. Female carriers are often phenotypically normal or show a similar but milder phenotype, as in most cases the X-chromosome harbouring the duplication is subject to inactivation. Xq28, which includes MECP2 is the major locus for submicroscopic X-chromosome duplications, whereas duplications in Xq25 and Xq26 have been reported in only a few cases. Using genome-wide array platforms we identified overlapping interstitial Xq25q26 duplications ranging from 0.2 to 4.76 Mb in eight unrelated families with in total five affected males and seven affected females. All affected males shared a common phenotype with intrauterine- and postnatal growth retardation and feeding difficulties in childhood. Three had microcephaly and two out of five suffered from epilepsy. In addition, three males had a distinct facial appearance with congenital bilateral ptosis and large protruding ears and two of them showed a cleft palate. The affected females had various clinical symptoms similar to that of the males with congenital bilateral ptosis in three families as most remarkable feature. Comparison of the gene content of the individual duplications with the respective phenotypes suggested three critical regions with candidate genes (AIFM1, RAB33A, GPC3 and IGSF1) for the common phenotypes, including candidate loci for congenital bilateral ptosis, small head circumference, short stature, genital and digital defects.

Clinical, dermoscopic and histopathologic features of genital and extragenital lichen sclerosus.

BACKGROUND: Little is currently known about the dermoscopic patterns of genital and extragenital lichen sclerosus (LS). In order to evaluate and compare the dermoscopic and histopathologic patterns of genital and extragenital lichen sclerosus, a retrospective analysis of clinical, dermoscopic and histopathologic features of genital and extragenital LS, collected between March 2010 and December 2011 at four dermatology clinics in Greece, Italy, Serbia and Uruguay was performed. OBSERVATIONS: A total of 29 lesions from 14 (mean age 62.8 years) and 12 (mean age 53.5 years) patients with genital and extragenital LS, respectively were analyzed. Mean duration of disease was 3.5 years for genital and 1.8 years for extragenital LS. White-yellowish structureless areas were seen in all cases of genital and extragenital LS; however linear vessels occurred at higher frequency in genital than in extragenital lesions (85.7% vs. 33.3%, respectively). Extragenital LS revealed two different time-related patterns: keratotic plugs were more prevalent in lesions with short duration (<2 years), whereas longer persisting lesions appeared atrophic and revealed fine chrysalis structures. CONCLUSIONS: Our morphologic study provides novel insights into the morphologic diversity of LS at different body sites and different stages of progression.

Preparation and properties of macroporous brushite bone cements.

In the present work a macroporous brushite bone cement for use either as an injected or mouldable paste, or in the shape of preformed grafts, has been investigated. Macropores have been introduced by adding to the powder single crystals of mannitol which worked as a porogen. The size of the crystals was in the range of 250-500microm in diameter, suitable for cell infiltration, with a shape ratio between 3 and 6. From compression tests on cylindrical samples an elastic modulus in the range 2.5-4.2GPa and a compressive strength in the range 17.5-32.6MPa were obtained for a volume fraction of macropores varying between 15 and 0%. Thus the compressive strength exceeded in all tests the maximum value currently attributed to cancellous bone.

Wetting in the nanoscale: a continuum mechanics approach.

A continuum mechanics model has been developed to study the equilibrium shape of nanometric droplets on a planar solid substrate and how, in this scale, the contact angle depends on the drop size. The drop is modeled as a liquid volume enclosed in an inextensible membrane, subject to an isotropic tension (the surface tension) and to a field of surface forces including, in the proximity of the solid, the liquid-to-solid interactions, envisaged as a generic potential force per unit surface directed normally to the solid surface (i.e. vertically). The only conditions required to solve the problem are those of mechanical and thermodynamic equilibrium. The predictions of the model are discussed in comparison with data on nanodrops retrieved by a special AFM device for a number of different liquid-solid systems.

The transcriptome of adult female Anopheles darlingi salivary glands.

Anopheles (Nyssorhynchus) darlingi is an important malaria vector in South and Central America; however, little is known about molecular aspects of its biology. Genomic and proteomic analyses were performed on the salivary gland products of Anopheles darlingi. A total of 593 randomly selected, salivary gland-derived cDNAs were sequenced and assembled based on their similarities into 288 clusters. The putative translated proteins were classified into three categories: (S) secretory products, (H) housekeeping products and (U) products with unknown cell location and function. Ninety-three clusters encode putative secreted proteins and several of them, such as an anophelin, a thrombin inhibitor, apyrases and several new members of the D7 protein family, were identified as molecules involved in haematophagy. Sugar-feeding related enzymes (alpha-glucosidases and alpha-amylase) also were found among the secreted salivary products. Ninety-nine clusters encode housekeeping proteins associated with energy metabolism, protein synthesis, signal transduction and other cellular functions. Ninety-seven clusters encode proteins with no similarity with known proteins. Comparison of the sequence divergence of the S and H categories of proteins of An. darlingi and An. gambiae revealed that the salivary proteins are less conserved than the housekeeping proteins, and therefore are changing at a faster evolutionary rate. Tabular and supplementary material containing the cDNA sequences and annotations are available at http://www.ncbi.nlm.nih.gov/projects/Mosquito/A_darlingi_sialome/

Primary characterization and basal promoter activity of two hexamerin genes of Musca domestica.

Hexamerins are high molecular-weight proteins found in the hemolymph of insects and have been proposed to function as storage proteins. In previous studies, two Musca domestica hexamerins, designated Hex-L and Hex-F were characterized. Hex-L is synthesized exclusively by the larval fat bodies, is secreted into the hemolymph and likely provides a source of amino acids and energy during metamorphosis. Hex-F synthesis is induced by a proteinaceous meal and occurs only in the adult insect fat bodies. Hex-F also is secreted into the hemolymph and it has been suggested that in females it may be an amino acid reservoir to be used during the final stages of egg formation. Genomic clones containing full-length copies of the genes MdHexL1 and MdHexF1, encoding subunits of the larval and the adult female hexamerin, respectively, were isolated. Complete nucleotide sequences, including the 5'-end untranscribed regions, were determined and analyzed for each of the genes. Comparisons of the conceptual translation products of the cloned genes indicated that MdHexL1 and MdHexF1 are related to the larval serum proteins (LSP) 1 and 2 of Calliphora vicina and Drosophila melanogaster. DNA fragments containing the putative promoters of the two hexamerin genes were compared and cloned into a plasmid vector so as to drive the expression of the GFP reporter gene. The constructs were assayed in vitro in transfected S2 Drosophila melanogaster cells demonstrating that the cloned M. domestica DNA fragments exhibit promoter activity.

The Musca domestica larval hexamerin is composed of multiple, similar polypeptides.

The Musca domestica larval hexamerin (MdHex-L) is a hexameric glycoprotein with an apparent native molecular weight of 500 kDa. Seven different cDNAs that encode MdHex-L subunits were cloned and sequenced. Furthermore, amino acid sequences of isolated subunits were determined by the Edman degradation method and compared to the conceptual translation products derived from the cloned cDNAs. The obtained data indicate the existence of multiple forms of MdHex-L subunits and that these multiple forms may be grouped into three categories according to their percentages of nucleotide sequence identity.

Androgen receptors in human melanoma cell lines IIB-MEL-LES and IIB-MEL-IAN and in human melanoma metastases.

The presence and characteristics of androgen receptors (ARs) have been described by our group in one human melanoma cell line. We have now investigated their presence in two other human melanoma cell lines, IIB-MEL-LES and IIB-MEL-IAN, as well as in biopsies from human metastatic melanoma. Scatchard analysis revealed a single binding component for both cell lines, the apparent dissociation constant obtained being 15 nM, with a binding capacity of 280 fmol/mg total cell protein, for IIB-MEL-LES cells and 14 nM, with a binding capacity of 206 fmol/mg total cell protein for IIB-MEL-IAN cells. When specificity was assessed, not only androgen and anti-androgen but also non-androgenic compounds were able to compete for [3H]R1881 binding, as seen before. When immunocytochemistry of IIB-MEL-LES and IIB-MEL-IAN cells was performed for ARs, both cell lines were deeply stained in the nucleus, whereas no staining was found for oestrogen or progesterone receptors. Every specimen of melanoma metastases tested for the presence of ARs was deeply stained, and in the majority the intensity of the staining was high. Several hormones and anti-hormones were tested for their ability to affect cell proliferation. In both cell lines, testosterone, dihydrotesterone, oestradiol and progesterone significantly stimulated cell proliferation, and this was reversed by hydroxyflutamide, bicalutamide or tamoxifen.

Tissue distribution and lipophorin transport of hydrocarbons and sex pheromones in the house fly, Musca domestica.

We investigated the relationship between epicuticular and internal hydrocarbons in the adult house fly, Musca domestica and the distribution of hydrocarbons, including the female sex pheromone component, (Z)-9-tricosene, in tissues. Internal hydrocarbons increased dramatically in relation to sexual maturation and were found in the hemolymph, ovaries, digestive tract, and fat body. (Z)-9-Tricosene comprised a relatively large fraction of the hydrocarbons in the female carcass and hemolymph, and less so in other tissues, while other hydrocarbons were represented in greater amounts in the ovaries than in other tissues. It therefore appears that certain hydrocarbons were selectively provisioned to certain tissues such as the ovaries, from which pheromone was relatively excluded. Both KBr gradient ultracentrifugation and specific immunoprecipitation indicated that > 90% of hemolymph hydrocarbons were associated with a high-density lipophorin (density = 1.09 g ml(-1)), composed of two apoproteins under denaturing conditions, apolipophorin I (approximately 240 kD) and apolipophorin II (approximately 85 kD). Our results support a predicted model (Chino, 1985) that lipophorin is involved in the transport of sex pheromone in M. domestica. In addition to delivering hydrocarbons and sex pheromones to the cuticular surface, we suggest that lipophorin may play an important role in an active mechanism that selectively deposits certain subsets of hydrocarbons at specific tissues.

[Study of association between the magnitude of sphincter hypotonia and esophageal motor disorders]. / Estudio de asociación entre magnitud de la hipotonía esfinteriana y trastorno motor del cuerpo esofágico.

BACKGROUND: One of the most important factors involved in the pathophysiology of gastroesophageal reflux disease (GERD) is the lower esophageal sphincter rest pressure (LESRP), but these patients can have esophageal motor disorders (EMD). AIM: To assess an association between LESRP and the appearance of EMD in patients with GERD. SUBJECTS AND METHODS: A cross-sectional study was conducted in 229 patients with GERD and 49 healthy controls. Forty five patients with LESRP < 6 mmHg and a mean age of 49 years were assigned to group 1, 128 patients with a LESRP between 6 and 12 mmHg and mean age of 47 years were assigned to group 2, 56 patients with a a LESRP > 12 mmHg and a mean age of 47 years were assigned to group 3 and group 4 was conformed by 49 healthy subjects aged 40 years old. Esophageal manometry was performed using previously published techniques. RESULTS: There was a significant association between LESRP, waves amplitude and the frequency of tertiary waves. CONCLUSIONS: Resting lower esophageal sphincter pressure is inversely proportional to the presence of esophageal motor disorders in patients with gastroesophageal reflux disease.

Relationship between serum growth hormone binding protein levels and height in young men.

The biochemical mediators responsible for variations in stature among normal subjects are largely unknown. To obtain some initial information about potential endocrine factors, we measured the serum concentrations of GH, IGF-1, IGFBP-3 and GHBP in healthy young men shorter than 159 cm and taller than 187 cm. We studied 14 volleyball and basketball players (tall group), and 14 jockey students from a horse racetrack (short group). A careful medical history was taken, including dietary intake, and physical examination with special attention to the possible presence of genetic stigmata was performed. Serum prealbumin was determined as an index of nutritional status. A buccal smear was performed to exclude Klinefelter's syndrome. The BMI and serum prealbumin levels were comparable in both groups of individuals. The nutritional survey, however, revealed that the tall subjects had a higher intake of calories (42.2+/-11.2 vs. 30.1+/-15.15 kcal/kg, p<0.05), and protein (1.5+/-0.6 vs. 0.8+/-0.4 mg/kg, p<0.01). Serum concentrations of GHBP did not differ in the two groups (0.95+/-0.37 nmol/l in the tall, and 0.95+/-0.53 nmol/l in the short group), and did not correlate with height, serum IGF-I levels, or BMI. We observed a significant difference in the serum concentrations of IGF-I in the two groups of individuals (42.02+/-9.37 nmol/l in the tall and 31.79+/-3.18 nmol/l in the short group, p<0.05), and this growth factor showed a positive correlation with height (r = 0.5, p<0.01). These preliminary findings suggest that final height differences in young men do not appear to be mediated by variations in GHBP concentrations.

HeLp, a heme lipoprotein from the hemolymph of the cattle tick, Boophilus microplus.

The main protein of the hemolymph of the cattle tick Boophilus microplus has been isolated and shown to be a heme lipoprotein (HeLp). HeLp has an apparent molecular mass of 354,000 and contains two apoproteins (103 and 92 kDa) found in equal amounts. HeLp presents a pI of 5.8 and a density of 1.28 g/ml and contains 33% lipids, containing both neutral lipids and phospholipids, and 3% of sugars. A remarkable feature of HeLp is the abundance of cholesterol ester (35% of total lipids), a lipid not previously reported in invertebrate lipoproteins. Western blot analysis showed HeLp in hemolymph from adult females and males, but not in eggs. Although HeLp contains 2 heme molecules, it is capable of binding 6 additional molecules of heme. Boophilus feeds large amount of blood, and we recently showed that this tick is unable to perform de novo synthesis of heme (Braz, G. R. C., Coelho, H. S. L., Masuda, H., and Oliveira, P. L. (1999) Curr. Biol. 9, 703-706). Injection of tick females with (55)Fe-labeled heme-HeLp indicated that this protein transports heme from hemolymph to tissues. HeLp is suggested to be an essential adaptation to the loss of the heme synthesis pathway.

Expression patterns of the larval and adult hexamerin genes of Musca domestica.

Hexamerins are proteins found in high abundance in the haemolymph of larval and adult insects. The expression patterns of the genes encoding the house fly, Musca domestica, hexamerins were determined by Northern analyses using cDNAs as probes. A cDNA, A1, hybridized to a fat body-specific messenger RNA (mRNA) which is detectable in larvae until pupation. Antibodies raised to the larval-specific hexamerin, Hex-L, bind recombinant protein encoded by a 5' rapid amplification of cDNA ends (RACE) product of A1, A2, indicating that the A cDNAs likely represent the genes encoding Hex-L. The F1, F2 and F3 cDNAs, corresponding to genes encoding an adult, female-enriched hexamerin, Hex-F, hybridized with an mRNA isolated from protein-fed females which has a temporal expression profile similar to that observed for the accumulation of Hex-F. Furthermore, expression of the mRNAs hybridizing to the F cDNAs is correlated with the abundance of Hex-F protein during the gonotrophic cycles. The mRNA transcription profiles indicate that the Hex-L and Hex-F genes are regulated in a sex-, tissue- and developmental phase-dependent manner. This stage-specific expression of hexamerins contrasts with the expression patterns of hexamerins seen in other insects. The conceptual translation products of larval hexamerin cDNAs showed identity with larval serum protein 1 (LSP1)-type hexamerins while the deduced products of the female hexamerin cDNAs showed the highest identity with LSP2-type hexamerins. Genomic analyses showed that the larval hexamerin and female hexamerin genes from M. domestica belong to two distinct multigenic families.

Prevalence of anemia in elderly subjects living at home: role of micronutrient deficiency and inflammation.

OBJECTIVE: Aging is associated with increased risk of developing anemia and micronutrient deficiencies. Wheat-based staple foods are iron fortified in Chile. We aimed to establish the prevalence and etiology of anemia in apparently healthy free-living elderly subjects. DESIGN AND SETTING: A cross-sectional study was performed in an outpatient clinic of Santiago, Chile. SUBJECTS AND METHODS: A group of 274 subjects (93 men, 181 women)>/=60 y old living at home and apparently healthy was studied. Clinical and anthropometric evaluations and dietary survey were performed. Complete blood count, and status of iron, copper, folate, vitamins B12 and A and C-reactive protein, and erythrocyte sedimentation rate were measured. RESULTS: Prevalence of anemia was 5.4% for men and 4.4% for women. Subjects with inflammatory process had a higher prevalence of anemia (22.2% men, 31.6% women). Abnormal serum retinol (<0.35 micromol/l) was found in 13.7% of men and 15.9% of women. Prevalence of folate deficiency (<7 nmol/l) was 50.5% in men and 33.1% in women. Low serum vitamin B12 (<148 pmol/l) was present in 51.1% of men and 30. 9% of women. Iron and copper deficiencies were infrequent. CONCLUSIONS: Anemia is not prevalent in free-living elderly subjects when iron intake is adequate. Inflammatory process is the main etiology of anemia in this age group. Vitamin A, folate and vitamin B12 deficiencies were found in a significant proportion of the study group. SPONSORSHIP: Sandoz Foundation for Gerontological Research.

Virus-expressed, recombinant single-chain antibody blocks sporozoite infection of salivary glands in Plasmodium gallinaceum-infected Aedes aegypti.

Transgenic mosquitoes resistant to malaria parasites are being developed to test the hypothesis that they may be used to control disease transmission. We have developed an effector portion of an antiparasite gene that can be used to test malaria resistance in transgenic mosquitoes. Mouse monoclonal antibodies that recognize the circumsporozoite protein of Plasmodium gallinaceum can block sporozoite invasion of Aedes aegypti salivary glands. An anti-circumsporozoite monoclonal antibody, N2H6D5, whose corresponding heavy- and light-chain gene variable regions were engineered as a single-chain antibody construct, binds to P. gallinaceum sporozoites and prevents infection of Ae. aegypti salivary glands when expressed from a Sindbis virus. Mean intensities of sporozoite infections of salivary glands in mosquitoes expressing N2scFv were reduced as much as 99.9% when compared to controls.

Use of alpha-tricalcium phosphate (TCP) as powders and as an aqueous dispersion to modify processing, microstructure, and mechanical properties of polymethylmethacrylate (PMMA) bone cements and to produce bone-substitute compounds.

Addition of tricalcium phosphate (alpha-TCP) powders as an aqueous dispersion to a polymethylmethacrylate (PMMA) bone cement is shown to produce a class of composites that due to their microstructure and mechanical properties may be suitable for application as bone substitutes. The PMMA forms a solid cellular matrix with open cells about 100 micrometer in size and incorporating TCP clusters. The TCP aggregates inside the cells form a porous network, with average mesopore diameters of about 0.1 micrometer, that is accessible from the outer surface. If TCP is added to PMMA in the form of dried powders, the composites are not applicable as bone substitutes. The dynamic elastic modulus (DEM) and compressive and tensile strengths were measured and discussed for both classes of composites. The mechanical properties of the bone-substitute composites, although lower than the other class of composites, are still competitive with those properties of a porous ceramic matrix of hydroxyapatite and with those of natural bones.

Differential lytic and agglutinating activity of the anti-Lewis(x) monoclonal antibody FC-2.15 on human polymorphonuclear neutrophils and MCF-7 breast tumor cells. In vitro and ex vivo studies.

The Lewis(x) (Le(x)) trisaccharide (CD15) linked to proteins and glycolipids is highly expressed on the surface of normal human polymorphonuclear neutrophils (PMN) and several human neoplasias, such as breast and gastrointestinal carcinomas and chronic myeloid leukemias. FC-2.15 is an IgM murine mAb that specifically recognizes Le(x) and has been previously shown to mediate the in vitro lysis of Le(x)(+) cells by human complement. In a phase I clinical trial of FC-2.15, a temporary neutropenia was the main toxicity, and antitumor responses were observed. In order to characterize FC-2.15 further and determine the physiological relevance of Le(x) binding, the reactivity of FC-2.15 on PMN was investigated under several conditions. Flow cytometry revealed a strong reactivity of FC-2.15 with almost 100% of PMN, and Scatchard analysis demonstrated an affinity constant of 5.14 x 10(9) M(-1) and 1.11 x 10(6) antigen sites/cell. In vitro, the binding of Le(x) epitopes by FC-2.15 induced PMN homotypic aggregation, only 28.4 +/- 4.1% remaining as single cells. When PMN and the Le(x)(+) MCF-7 breast cancer cells were co-incubated, FC-2.15 induced heterotypic aggregation. In 51Cr-release assays employing human complement, FC-2.15 lysed 93.4 +/- 7.9% of PMN and 87.8 +/- 10.7% of MCF-7 cells. However, when the effect of FC-2.15 was tested in ex vivo circulating blood, no lytic activity against PMN was detected, whereas MCF-7 cells were still lysed. Blood smears demonstrated that FC-2.15 induced PMN agglutination and heterotypic aggregates when MCF-7 cells were present. A pretreatment of PMN with colchicine impaired PMN agglutination both in vitro (single PMN = 81.15 +/- 4.35%) and in ex vivo circulating blood. In the latter condition, FC-2.15-lytic activity was restored, suggesting that PMN homotypic aggregation by FC-2.15, but not lysis, is dependent on microtubule integrity and that PMN agglutination hinders their lysis. Moreover, when 51Cr-release assays were performed following agglutination, FC-2.15 cytotoxicity was restricted to isolated PMN. It is suggested that crosslinking of Le(x) epitopes by FC-2.15 induces PMN to form homotypic aggregates. It is suggested that the neutropenia observed in FC-2.15-treated patients would be due to PMN agglutination and margination, rather than lysis. In addition, FC-2.15 appears to be able to lyse Le(x)(+) tumor cells in circulation.