Development of normal mice from metaphase I oocytes fertilized with primary spermatocytes

Primary spermatocytes are the male germ cells before meiosis I. To examine whether these 4n diploid cells are genetically competent to fertilize oocytes and support full embryo development, we introduced the nuclei of pachytene/diplotene spermatocytes into oocytes that were arrested in prophase I (germinal vesicle stage), metaphase I, or metaphase II (Met II). Both the paternal and maternal chromosomes then were allowed to undergo meiosis synchronously until Met II. In the first and second groups, the paternal and maternal chromosomes had intermingled to form a large Met II plate, which was then transferred into a fresh enucleated Met II oocyte. In the third group, the paternal Met II chromosomes were obtained by transferring spermatocyte nuclei into Met II oocytes twice. After activation of the Met II oocytes that were produced, those microfertilized at metaphase I showed the best developmental ability in vitro, and three of these embryos developed into full-term offspring after embryo transfer. Two pups (one male and one female) were proven to be fertile. This finding provides direct evidence that the nuclei of male germ cells acquire the ability to fertilize oocytes before the first meiotic division.     

Dynamic compaction of amorphous Ni75Si8B17 and Pd78Cu6Si16 alloys

Amorphous Ni₇₅Si₈B₁₇ and Pd₇₈Cu₆Si₁₆ alloy powders were dynamically compacted using a propellant gun. The degree of compaction increases with increase in the magnitude of shock pressure. The shock pressure giving the highest degree of compaction is lower in Pd₇₈Cu₆Si₁₆ than in Ni₇₅Si₈B₁₇. The progress of compaction-induced crystallization is faster in Pd₇₈Cu₆Si₁₆ than in Ni₇₅Si₈B₁₇, reflecting the difference in their exothermic characteristics during heating. Evidence was found for a melting and solidification mechanism of dynamic compaction of amorphous powders.     

Sequential changes in full-length genomes of hepatitis B virus accompanying acute exacerbation of chronic hepatitis B

BACKGROUND/AIM: During the course of persistent hepatitis B virus infection, viral replication markedly decreases after acute exacerbation of liver inflammation accompanied by emergence of antihepatitis B e antibody (anti-HBe) and/or anti-hepatitis B surface antibody (anti-HBs). In some cases, however, persistent viral replication continues even after such exacerbation with or without HBeAg/anti-HBe seroconversion. The aim of the present study was to investigate the extent of genetic variations of HBV in this phenomenon. METHODS: Full-length HBV genomes were amplified by polymerase chain reaction from sera of three patients before and after acute exacerbation and were directly sequenced. RESULTS: In the whole genomes of 3215 nucleotides, only six nucleotide mutations for six amino acid substitutions (2 in the surface gene, 2 in the X gene, 1 in the core gene and 1 in the polymerase gene) were observed in patient 1, 15 mutations for 14 amino acid substitutions (1 in the pre-core codon 28, 4 in the surface gene, 4 in the core gene and 5 in the polymerase gene) were observed in patient 2, and 5 mutations for 6 amino acid substitutions (2 in the surface gene, 2 in the X gene, pre-core stop codon mutation and 1 in the polymerase gene) were observed in patient 3. Substitution in the a determinant of the surface gene, which encodes target epitopes for neutralizing antibodies, as well as those in the pre-core/core gene, which encodes epitopes for cytotoxic T cells, were mainly found. CONCLUSION: HBV that remained after the emergence of anti-HBe and anti-HBs are considered to possess mutations in epitopes for both humoral and cellular immunity. These mutant HBV may be involved in the pathogenesis of persistent hepatic injury after acute exacerbation.     

Estimation of the energy of cytoplasmic movements by magnetometry:effects of temperature and intracellular concentration of ATP

Ferrimagnetic particles (gamma-Fe2O3) were spontaneously phagocytized by pulmonary macrophages obtained from the lungs of hamsters. By the magnetometric method proposed earlier, changes in the energy of the movements of the intracellular structures and also that of the apparent viscosity of the cytoplasm were estimated. The changes were created by lowering the incubation temperature or by decreasing the intracellular concentration of ATP. While the low temperature decreased the energy and increased the apparent viscosity, the low concentration of ATP decreased the energy but had little effects on the apparent viscosity. Estimation of the these parameters was based on the model previously proposed.     

The significance of a positive flow cytometry crossmatch test in primary kidney transplantation

This study was conducted to determine the efficacy of the T cell flow cytometry crossmatch (T-FCXM) test in 841 first cadaver donor transplants. Results showed one-year graft survival rates were 82% for T-FCXM-negative patients, compared with 75% for T-FCXM-positive patients (P = 0.01). Early one-month graft failure was 13 percentage points higher in those with a positive T-FCXM than those with a negative T-FCXM. The positive crossmatch patients also had more frequent immunological failures. A positive T-FCXM was found in 39% of the sensitized patients (PRA > 10%) and 8% of those who had not been sensitized. Patients with a positive T-FCXM in either category had a 74% graft survival rate. Thus, most of the T-FCXM-positive results occurred in patients with complement-fixing antibodies. It is suggested that flow cytometry crossmatching (FCXM) be used prospectively, despite the fact that many patients with a positive crossmatch did have successful transplants (TXs). In the current climate of a cadaver kidney scarcity and large recipient waiting pools, utilization of kidneys for patients with the highest probability of success seems a most prudent policy.     

Pixels consisting of a single vertical-cavity laser thyristor and adouble vertical-cavity phototransistor

Bidirectionally cascadable optical pixels that consist of a single-vertical-cavity surface-emitting laser (VCSEL) thyristor and a double-vertical-cavity phototransistor are proposed. Despite almost identical layer structures, each device characteristic can be independently optimized by introducing a λ/2-spacer layer into the phototransistor section. A lasing threshold of 0.8 mA and a slope efficiency of 0.25 W/A are obtained for the laser thyristor, and a flat-topped photocurrent spectrum over 30 A and a photocurrent gain of 70 A/W are obtained for the phototransistor at the resonant wavelength. This work demonstrates the possibility of monolithic integration using thermal desorption and a regrowth technique and the suitability of these devices for massively parallel optical interconnections     

New control chart for multivariate data with missing values

A new multivariate statistical quality control method has been developed. It is an extension of the method developed by Kume, which is able to find abnormal values in multivariate biochemical data of a clinical laboratory. The present method makes use of the difference between two sets of data measured from the samples of the same patient obtained on different days. The Mahalanobis' distance between two samples can be calculated from the difference of their observations. If the Mahalanobis' distance of the two data is larger than the critical value decided in advance, the reliability of the measurement is doubtful. The characteristic of the present method is that it can apply to data with missing values by estimating them from measured data. Some numerical examples are shown to demonstrate the availability of the method.     

Cyclic tensile creep behaviour of cellulose nitrate and evaluation of constitutive equations

The cyclic creep behaviour under axial tension was quantitatively investigated using non-linear viscoelastic cellulose nitrate heated at 65°C. The instantaneous strains at the instants of loading and unloading for three creep cycles and the creep strain rates during the three creep cycles were found to be influenced by the cycle numbers. However, the effect of the cycle number on the loading process was quite different from that on the unloading process in the cyclic creep deformation. The evaluation of the creep constitutive equations for the loading and unloading processes at one loading cycle deduced in the previous papers is discussed for the cyclic creep deformation. The deduced creep equations give good agreement with the actual observations for the three creep cycles independent of the cycle numbers and of the creep stress levels.     

Proteolysis of the phage lambda CII regulatory protein by FtsH (HflB) of Escherichia coli

BACKGROUND: It has been suggested that the expression of psychosis may reflect an active morbid process that is associated with increasingly poor outcome unless ameliorated by antipsychotic drugs. METHODS: The subjects of this study were 48 in-patients with schizophrenia, many of whom had been admitted before the introduction of antipsychotic drugs to rural Irish psychiatric hospitals in the late 1950s. Each patient was assessed for positive and negative symptoms, and for general and executive (frontal) cognitive function. RESULTS: After controlling for age and for duration and continuity of subsequent antipsychotic treatment, current severity both of negative symptoms and of general cognitive impairment was predicted strongly by increasing duration of initially untreated psychosis; duration of illness following initiation of antipsychotic medication failed to predict the severity thereof. Neither of these indices of illness duration predicted the severity of positive symptoms or of executive dyscontrol. CONCLUSIONS: Increasing duration of initially untreated psychosis was associated specifically with heightened accrual of prominent negative symptoms and general cognitive impairment. Executive dyscontrol, though also prominent in these patients, may be 'locked-in' at an earlier phase of the illness.     

Intersubunit structure within heterodimers of medium-chain prenyl diphosphate synthases. Formation of a hybrid-type heptaprenyl diphosphate synthase

The later work of Wittgenstein (1953) takes language and meaning as arising in use. A local 'grammar' is created. Ethical/research awarding committees have developed, and clashing, meanings about what constitutes 'good' research. The fixed rule language game of the committee is implicitly powerful because it is part of well-rehearsed societal narratives which equate science and knowledge. This creates a force on the qualitative researcher to conform to the authoritative grammar which it is difficult to counter. In these circumstances, qualitative researchers may choose to inhabit two, parallel research universes by 'storying' their research proposal according to the audience. But a question arises as to whether ethical approval has been gained when a 'Trojan horse' approach is used. Moving between worlds involves the researcher living with a dual identity. The postmodernist movement away from structure, form and singular truth is seen as setting a context for a new archaeology of knowledge which transcends good/bad dichotomies in relation to research. The qualitative researcher is encouraged to enter into dialogical communication with committees with the hope that a shared grammar may emerge.