Oocyte activation in invertebrates and humans.
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Animals↗
Biomedical subjects
B Dale
Publications and source records attributed to B Dale.
Vaccination against the cat flea Ctenocephalides felis felis.
Non-chemical control of haematophagous parasites is a desirable goal. We report here on the use of concealed antigens from the major digestive organ of the cat-flea as vaccine components. Rabbits were immunized with various antigens from cat flea midguts, and immunoglobulin from these rabbits was fed to cat fleas in an artificial feeding system. Antibody produced against soluble antigens from the midguts of fed fleas was able to kill fleas in this system. Dogs were then immunized with various antigen preparations, and challenged for a week with live fleas. Significantly fewer live fleas were recovered from dogs immunized with fed midgut supernatant, and recovered live female fleas produced significantly fewer eggs. This study indicates the possibility of vaccination as a means of control of flea, and possibly other blood sucking insect populations.
Animals↗
Inositol tri-phosphate inhuman and ascidian spermatozoa.
Using a specific protein binding assay we have shown that a spermatozoon of the ascidian Ciona intestinalis contains 1.58 +/- 0.74 x 10(-19) moles of inositol 1,4,5-tri-phosphate (InsP3), while a human spermatozoon contains 6.4 +/- 0.14 x 10(-19) moles. Induction of the acrosome reaction (AR) in both species, by exposure to the calcium ionophore A23187, does not significantly alter levels of InsP3, suggesting that phosphatidylinositol (PI) turnover is not necessary for the calcium ionophore induced AR. Furthermore, PI turnover in ascidian spermatozoa appears to be insensitive to lithium and phorbol ester. The high intracellular concentration of InsP3 in spermatozoa, corresponding to 50-200 microM, suggests it may play a role in egg activation.
Acrosome↗
Activation currents, sperm entry and surface contractions in ascidian eggs.
Spermatozoa from the mollusc Ostrea edulis are capable of fusing to and entering de-chorionated ascidian eggs. During interaction they generate activation currents, comparable to the fertilisation currents induced by homologous spermatozoa. Activation currents are inward at -80 mV, with a mean initial slope of 111 +/- 124 pA/s for Ciona intestinalis eggs and 47 +/- 25 pA/s for Phallusia mammillata eggs, while the mean peak currents are 2782 +/- 1132 pA and 1523 +/- 1668 pA, respectively. The fertilisation and activation currents reverse at a holding potential of 0 mV to + 20 mV, suggesting that oyster sperm and ascidian sperm gate the same channel precursor, a non-specific, large conductance channel described previously (Dale & DeFelice, 1984). In contrast to homologous fertilisation, the activation current is not followed by a polarised contraction of the egg surface, nor other signs of egg activation. Staining eggs with Hoechst 33342 after insemination shows the female nucleus and a single oyster sperm nucleus at the antipode. This suggests a specialised predetermined site at the vegetal pole for sperm entry. Homologous and heterologous spermatozoa delivered, in a large pipette, to localised areas of the egg surface generate fast inward currents of 200-2000 pA, but do not induce contraction of the egg surface. This shows that although channel precursors are located globally over the egg surface, channel activation does not necessarily trigger the contraction wave. Subsequent induction of both a fertilisation current and a contraction by homologous sperm added to the bath, implies a regionalised activation site with an accumulation of channel precursors and a 'pacemaker' for the initiation of the contraction wave.
Action Potentials↗
Fluconazole chemoprophylaxis in neutropenic patients.
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Adult↗
Magnetic properties of ultrafine iron particles.
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Journal Article↗
Tight junctions and cavitation in the human pre-embryo.
In the human morula, tight junctions are found between all cell pairs, at all levels of cellular apposition, associated with underlying masses of microfilaments. In cavitating morula, lanthanum tracer gained access to the intracellular spaces, except at the intersections with nascent extracellular cavities, marking the first assembly of zonulae occludentes. Presumptive trophectoderm cells contained vacuoles and larger cavities often associated with secondary lysosome-like bodies. Since the vacuoles and intracellular and extracellular cavities contain electron-dense polygranules of about 23 nm diameter, they may have common origins. In trophectoderm cells of the early blastocytes, the large intracellular vacuoles and cavities were absent, and the zonulae occludentes were located apically. Mechanisms for nascent blastocoele formation are discussed.
Blastocyst↗
Sequence analysis and editing of the phosphoprotein (P) gene of rinderpest virus.
We have cloned the cDNA of the phosphoprotein (P) gene of the virulent (Kabete "O") strain of rinderpest virus and provided a comparative analysis of its sequence with that of the P genes of measles, canine distemper, and phocid distemper viruses. The gene encodes two overlapping open reading frames of 1521 and 531 nucleotides. Use of the first ATG would produce a P polypeptide of 507 amino acids with a calculated molecular weight of 54,344. The second ATG would produce a C polypeptide of 177 residues with a predicted molecular weight of 19,927. In addition, the insertion of a G residue at position 740 generates an alternative mRNA potentially encoding the V polypeptide of rinderpest virus. The homology comparisons in P amino acid sequences between rinderpest and measles, between rinderpest and canine distemper, and between rinderpest and phocid distemper viruses are 60, 44, and 46%, respectively. A four-way comparison shows an identity of 34%. Similar homology comparisons with the C amino acid sequence between rinderpest and measles, rinderpest and canine distemper, and rinderpest and phocid distemper viruses are 56, 42, and 40%, respectively. A homology of 31% is found in a four-way comparison for the C polypeptide. From the point of the insertion of the G residue, there is a homology of 78% between the V polypeptides of rinderpest and measle viruses.
Amino Acid Sequence↗
Molecular characterization of a Dirofilaria immitis cDNA encoding a highly immunoreactive antigen.
Dirofilaria immitis, a filarial nematode, is the causative agent of canine and feline heartworm disease. Previous research has demonstrated that immunity to D. immitis can be induced in dogs by repeated chemical abbreviation of infections while the parasite is a fourth-stage larva. Sera obtained from dogs immunized in this manner has been effective in passively transferring larval killing and stunting. These immune sera, by comparison to nonimmune sera from infected cohorts, recognize a number of unique D. immitis antigens, some of which are larval specific. In this study immune dog sera were used to screen a D. immitis larval cDNA expression library. Three overlapping cDNA clones, Di22, Di18 and Di16, were obtained that encode a portion of a large molecule, greater than 150 kDa, that is composed of multiples of a 399-bp repeat. This protein when immunoblotted with antibody against a recombinant expressed Di22 fusion protein is found in larval as well as adult extracts and excretory-secretory products, and is seen as a series of ascending subunits, each approximately 15 kDa larger than the previous one. This antigen is highly immunogenic, as evidenced by the strong reactivity of the recombinant expressed Di22 fusion protein with sera from immune dogs, microfilaremic dogs and infected amicrofilaremic dogs. While the function of this antigen is unknown it has significant sequence similarity with an allergen found in Ascaris.
Amino Acid Sequence↗
Is the human oocyte plasma membrane polarized?
Using scanning electron microscopy, we have shown that the plasma membrane of the human metaphase II oocyte is organized in evenly spaced, short microvilli of 1-3 microns in length. In contrast to other mammals studied to date, there is no microvillus-free area overlying the metaphase spindle and there were no other indications of polarization at this level of organization. Functional polarity of the plasma membrane, studied using localized microsurgery of the zona pellucida followed by insemination, suggests that sperm fusion and entry in the human may occur anywhere over the oocyte surface. Aged oocytes and those exposed to acidic Tyrode's solution had surfaces which were not homogeneously covered by microvilli. Oocytes exposed to a sucrose solution and subzonally injected with spermatozoa showed evidence of partial cortical granule exocytosis.
Cell Membrane↗
The perivertebral collar--a new sign in lymphoproliferative malignancies.
Nine patients with lymphoproliferative malignancies, one of whom had not been previously diagnosed, were found on CT examination for back pain to have partial or complete soft tissue perivertebral collars. The thoracic and or lumbar regions were involved in all. Only 3 had gross bony changes at the time, and in others the changes appeared so innocuous that in combination with the vague clinical symptoms their significance was underestimated. Five patients ultimately had episodes of cord compression, and in all nine the appearance of this spinal lesion appeared to be of grave prognostic significance. All 9 were dead within 1 year of the presentation of their spinal lesions. The observation of a perivertebral collar in the context of a known or suspected lymphoproliferative malignancy should therefore raise the strong suspicion of spinal involvement. The vertebrae should be examined on bone windows and the contents of the spinal canal on narrow windows to assess bony and epidural spread.
Adult↗
A follow-up study of problem drinkers offered a goal choice option.
Patients (N = 100) who had been admitted to behaviorally oriented residential treatment for their drinking problems were followed up for 1 year. A treatment goal option of controlled drinking was explicitly catered for. Overall outcome, in which 27% of those available for follow-up were categorized as "successful," 35% as "equivocal" and 38% as "failure," does not appear to be markedly dissimilar to that reported from other agencies. The distribution of approximately equal abstinent and nonabstinent successful outcomes is similar to that found following treatment programs that promote a single goal. Sociodemographic variables were less influential in predicting outcome than were treatment variables--with frequency of aftercare attendance being particularly significant. Those who had received previous hospital treatment for their problem, those who habitually drank in company and those who had abnormal blood test results prior to entering treatment had poorer outcome.
Adult↗
Ongoing development of the Critical Care Information System: the collaborative approach to automating information management in an intensive care unit.
Point-of-care (bedside) clinical information systems can fulfill a variety of functions. Included in these functions are: becoming receptacles for patient data and allowing data to be manipulated into formats that facilitate clinical decision making; functioning as sources for billing and auditing processes; interfacing to other hospital systems and bringing distant data to the bedside; and being a repository for information used in the development of hierarchical and/or relational databases. The initial and ongoing development of these systems in a dynamic clinical environment requires the construction of processes and work pathways to ensure that the needs and requirements of myriad personnel, departments and agencies within the health center milieu are addressed.
Administrative Personnel↗
Feline leukemia virus vaccine development.
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Adjuvants, Immunologic↗
Intercellular communication in the early human embryo.
A preliminary study on intercellular communicative devices in the early human embryo has been made using dye-coupling techniques and electron microscopy (EM). Lucifer yellow injected into single blastomeres of embryos at the 4-cell stage up to the late morula stage did not spread to neighbouring cells, indicating that gap junctions and cytoplasmic bridges are not significant pathways for information transfer. Dye spread was first observed in the blastocyst stage, where trophectoderm cells and inner mass cells were shown to be in communication through gap junctions. Studies at the EM level confirmed this finding. Tight junctions and desmosome-like structures, apparent from the 6-cell stage onward, were located both peripherally and centrally and were initially nonzonular. The role of intercellular devices in the primary differentiation of the human embryo is discussed.
Blastocyst↗
L-type Ca2+ currents in ascidian eggs.
We have studied Ca2+ currents in ascidian eggs using the whole-cell clamp technique. T and L components, as observed in somatic cells, are present and the L-type current predominates. Since the IV relationship for these inward currents overlap at -30 mV, separation of the two components using different voltage regimes is not feasible. Increasing external Ca2+ results in larger currents. The L-type current decreases in a dose-dependent fashion in the presence of Mn2+ and Nifedipine, while the T-type current is inhibited in Ni2+. When Ba2+ was used as the carrier ion, channel kinetics and conductance were completely altered. Considering the density and kinetics of L-type channels in unfertilized eggs it is probable they play an important role in regulating cytosolic Ca2+ during early developmental processes.
Animals↗
GM-CSF after allogeneic bone marrow transplantation: accelerated recovery of neutrophils, monocytes and lymphocytes.
Ten patients given HLA-identical sibling marrow transplants for lymphoid malignancy received recombinant human granulocyte macrophage-colony stimulating factor (GM-CSF) from day 7 to day 13 inclusive post transplant. Patients were prepared for transplantation with busulphan 16 mg/kg and cyclophosphamide 120 mg/kg. Immunosuppression to minimise the risk of graft-versus-host disease (GVHD) was cyclosporin/short methotrexate. Results were compared with a historical control group of patients (n = 16) given matched sibling transplants for acute leukaemia and receiving the same immune suppressive regime but not given GM-CSF. Recovery of total white cells, neutrophils, monocytes and lymphocytes was more rapid in the GM-CSF recipients (p less than 0.02). There was a suggestion of a decrease in non-viral infections in the first 30 days in the GM-CSF recipients (p = 0.09). There was, however, no significant difference in the severity of oropharyngeal mucositis nor in the duration of the transplant hospitalisation. Surprisingly, the severity of acute GVHD was higher in the GM-CSF recipients with six of eight evaluable patients having grade II-IV acute GVHD (p = 0.003). Two GM-CSF recipients developed a fluid retention/capillary leak syndrome. These findings indicate a need for caution in the use of GM-CSF after allogeneic marrow transplantation.
Adolescent↗
Gap-junctional permeability in early and cleavage-arrested ascidian embryos.
Using the whole-cell voltage clamp technique, we have studied junctional conductance (Gj), and Lucifer Yellow (LY) coupling in 2-cell and 32-cell ascidian embryos. Gj ranges from 17.5 to 35.3 nS in the 2-cell embryo where there is no passage of LY, and from 3.5 to 12.2 nS in the later embryo where LY dye spread is extensive. In both cases, Gj is independent of the transjunctional potential (Vj). Manually apposed 2-cell or 32-cell embryos established a junctional conductance of up to 10 nS within 30 min of contact. Furthermore, since we did not observe any significant number of cytoplasmic bridges at the EM and Gj is sensitive to octanol, it is probable that blastomeres in the 2-cell and 32-cell embryos are in communication by gap junctions. In order to compare Gj in the two stages and to circumvent problems of cell size, movement and spatial location, we used cytochalasin B to arrest cleavage. Gj in cleavage-arrested 2-cell embryos ranged from 25.0 to 38.0 nS and remained constant over a period of 2.5 h. LY injected into a blastomere of these arrested embryos did not spread to the neighbour cell until they attained the developmental age of a 32- to 64-cell control embryo. Our experiments indicate a change in selectivity of gap junctions at the 32-cell stage that is not reflected by a macroscopic change in ionic permeability.
Animals↗