Human mini-chromosomes in mouse embryonal stem cells

We have introduced human mini-chromosomes of 4 Mb and approximately 15 Mb in size into mouse embryonal stem cells. Although these human mini- chromosomes are stable in hamster and chicken cells, they re-arrange or segregate aberrantly in the embryonal stem cells and are rapidly lost in the absence of selection. However, one of the mini-chromosomes re- arranged, acquired mouse centromeric sequences and was then stably maintained for at least 60 population doublings in culture. This mini- chromosome, which is 4 Mb in size, is a candidate for a mouse germ line chromosome vector.      

Determination of the parent of origin in nine cases of prenatally detected chromosome aberrations found after intracytoplasmic sperm injection

Prenatal cytogenetic analysis of 71 fetuses conceived by intracytoplasmic sperm injection (ICSI) resulted in the detection of nine (12.7%) chromosome aberrations including two cases of 47,XXY, four cases involving a 45,X cell line and three autosomal trisomies. Molecular analysis of the parental origin of the deleted or supernumerary chromosome was performed by using polymorphic microsatellite markers. Six cases involving a sex chromosome abnormality were found to be of paternal origin while the two trisomic cases that could be analysed were of maternal origin. Two cases involved the same infertile couple who had two consecutive ICSI pregnancies terminated because of a chromosome abnormality. The replaced embryos in both cases originated from a single batch of ICSI fertilized oocytes of which part was used to initiate the first pregnancy and part was cryopreserved and used to initiate the second pregnancy.      

The effect of calcium ion concentration on osteoblast viability, proliferation and differentiation in monolayer and 3D culture

Our research group aims to develop an osteochondral composite using type II collagen gel with hydroxyapatite (HAp) deposited on one side. Soaking gels in Ca2+ and phosphate solution is indispensable to HAp deposition, so relationships between cell behavior and Ca2+ concentration were examined in two- and three-dimensional cultures. The present results indicate that 2-4 mM Ca2+ is suitable for proliferation and survival of osteoblasts, whereas slightly higher concentrations (6-8 mM) favor osteoblast differentiation and matrix mineralization in both 2- and 3-dimensional cultures. Higher concentrations (>10 mM) are cytotoxic. Purely from the perspective of calcium deposition, higher concentrations lead to increased accumulation of Ca2+. Culturing cells in phosphate-containing gel in media with Ca2+ also leads to time-dependent formation of HAp in the gel. Considering the viability of embedded cells, culturing scaffolds in media with Ca2+ concentrations around 5mM is useful for both HAp deposition and osteoblast behavior.     

Integration of retinal and motor signals of eye movements in striate cortex cells of the alert cat

Responses of saccade-depressed (SD) and saccade-excited (SE) cells in the striate cortex to eye movements of alert cats under presentation of a visual pattern were studied under reinforcement of the eye movements with rewards of water. These responses were compared to those on passive displacement of the visual pattern reproducing the movements of the retinal image occurring during eye movements while eye movements were suppressed by withdrawal of reinforcement. Passive displacement of the visual pattern produced in the SD cells depression closely resembled the depression occurring during eye movements under presentation of the visual pattern, in time course as well as in amplitude. Both the saccade depression and the depression due to passive movement of the visual pattern were nonselective to the direction of eye movements. Saccade excitation of the SE cells frequently contained two components occurring at 20 and 80 ms after the onsets of eye movements. Passive displacement of the visual pattern produced in the SE cells excitation comparable with the early component of the saccade excitation. These findings suggest that saccade depression in the SD cells and the early component of the saccade excitation in the SE cells are related to retinal reafference of eye movement. During presentation of visual patterns, saccade excitation in the SE cells was closely related to parameters of eye movements, such as direction, amplitude, duration, and velocity. The correlations were completely lost or strongly reduced in darkness. Lines of evidence were provided that the saccade excitation of the SE cells in darkness or the later component of the saccade excitation under presentation of a visual pattern represents efference copy signals of eye movement transferred to the striate cortex through the Clare-Bishop (CB) cortex. Excitation comparable with saccade excitation in darkness occurred in synchrony with activities of the oculomotor nuclei even after retrobulbar paralysis of eye movement, indicating that the excitation is related to efference copy signals rather than proprioceptive reafference of eye movement.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effect of vitamin K2 on cortical and cancellous bones in orchidectomized young rats

OBJECTIVES: The purpose of the present study was to compare the effect of vitamin K(2) on cortical and cancellous bones in orchidectomized young rats. METHODS: Forty male Sprague-Dawley rats, 6 weeks of age, were randomized by stratified weight method into four groups with 10 rats in each group: baseline controls (BLC), age-matched controls (AMC), orchidectomy (ORX), and ORX+vitamin K(2) administration (K). Vitamin K(2) (menatetrenone) was administered subcutaneously twice a week at dose of 30 mg/kg each. The experimental period was 8 weeks, and cortical and cancellous bone histomorphometry was performed on the tibial shaft and the proximal tibia, respectively. RESULTS: Cortical area (Ct Ar) and cancellous bone volume (BV/TV) were significantly greater in the AMC group than in the BLC group. Ct Ar was significantly lower in the ORX group than in the AMC group, and cancellous BV/TV was also significantly lower in the ORX group than in the AMC group as a result of significantly increased eroded surface (ES/BS). Although Ct Ar in the ORX+K group did not differ significantly from that in the ORX group, cancellous BV/TV was significantly greater in the ORX+K group than in the ORX group, but still significantly lower than in the AMC group. This protective effect of vitamin K(2) on cancellous bone was attributable to normalizing increased ES/BS. CONCLUSIONS: Vitamin K(2) appears to act more strongly on cancellous bone than on cortical bone in ORX young rats. High dose vitamin K(2) could partially prevent the reduction of cancellous bone gain by normalizing raised bone resorption in ORX young rats.     

Eye movement-related activities in cells of the lateral suprasylvian cortex of the cat

Investigation of eye movement-related activities and photic responsiveness using behaving cats demonstrated distinctive representations of eye movement signals in different areas of the lateral suprasylvian cortex: visual reafference in the medial bank of the middle suprasylvian sulcus and non-visual signals (proprioceptive reafference or efference copy) in the lateral bank.     

Age-dependent variation of T1 and T2 relaxation times of adenocarcinoma in mice

The T1 and T2 values of adenocarcinoma EO 771 inoculated into the hind leg of mice are characterized and correlated with the histopathologic state of the tumor. Growth-dependent changes (indicated by a T1 of 630-910 msec and a T2 of 68-185 msec) can be separated into four characteristic phases. The increase in relaxation times in the early phases (A and B) is due to an increasing amount of viable tumor tissue relative to normal muscle tissue. In the later phases (C and D), a decline of the relaxation parameters is observed that is parallel to an increase in the fraction of necrotic tissue. By multiexponential analysis, two relaxation components (indicated by and, respectively) for T1 and T2 and the corresponding fractions alpha 1 and alpha 2 can be observed for both tumor and surrounding muscle tissue. A tissue criterion ("magnetic resonance fingerprint") is defined by a combination of these multiple parameters. This criterion allows separation of not only muscle and tumor tissue but also viable (early state) and necrotic (late state) tumor tissue.     

Giving a voice to patient experiences through the insights of pragmatism

As a philosophical position, pragmatism can be critiqued to distinguish truth only with methods that bring about desired results, predominantly with scientific enquiry. The article hopes to dismiss this oversimplification and propose that within mental health nursing, enquiry enlightened by pragmatism can be anchored to methods helping to tackle genuine human problems. Whilst pragmatists suggest one reality exists, fluctuating experiences and shifting beliefs about the world can inhabit within; hence, pragmatists propose reality has the potential to change. Moreover, pragmatism includes being cognisant of what works to whom reality concerns, making reality context-driven, with a view to understand how actions shape experiences so what is generated has usefulness. Hence, it somewhat follows pragmatism can inform mental health nursing, after all, nursing is a discipline of action, and awareness is needed in how actions produce experiences that patients find helpful. Given the principles of recovery are preferably adopted in mental health care, the paper will explore how pragmatism can help nurses move towards that goal; specifically, with patients voicing their experiences. This is because like pragmatism, recovery subscribes to hope that reality can progress, and through meaningful experiences and beliefs, patients have expertise about personal difficulties alongside how life may flourish, despite mental illness.     

Successful Single-Lung Transplant for the Dominant Side: A Case Report

Although single-lung transplant on the side with better lung function is challenging in patients with significantly asymmetrical lung function between the right and left sides, it sometimes can be a realistic option because of the recipient's condition and from the viewpoint of organ sharing. We report our experience with a successful case of single-lung transplant on the side with a pulmonary perfusion ratio of 89%. The transplant was performed with the patient under central venoarterial extracorporeal membrane oxygenation through a clamshell incision, and the patient had an acceptable short- and long-term outcome with a remarkable improvement of lung function.     

Electrical activity of red nucleus neurones investigated with intracellular microelectrodes

Summary Microelectrodes were inserted into the magnocellular portion of cat's red nucleus (RN), and some basic physiological properties of RN cells were examined by both extra- and intracellular recording. During stimulation of the rubrospinal fibres at the spinal segmental level, the RN cells were invaded antidromically, producing conspicuous field potentials within RN. The somatotopical distribution of RN cells was confirmed by comparing the field potentials induced from C₂ and L₁ levels. When recorded intracellularly, antidromic action potentials showed three-step configuration as those in motoneurones and were followed by a remarkable after-hyperpolarization. The conduction velocity along the rubrospinal fibres ranged from 41–123 m/sec, with the peak frequency at 91–100 m/sec. The membrane properties were examined in some RN cells by intracellular application of current steps. The total membrane resistance was 4 M on the average, and the membrane time constant 6 msec, respectively.Excitatory postsynaptic potentials (EPSPs) were induced monosynaptically in RN cells by stimulation of the nucleus interpositus of the contralateral cerebellum. Their time course was analyzed in comparison with that of the potentials produced by current steps. Stimulation in the ventrolateral nucleus of the thalamus evoked monosynaptic EPSPs via the collaterals of the interpositus axons which innervate RN and thalamus commonly. It was further shown that impulses in cortico-rubral fibres produced EPSPs in RN cells. These cerebral-evoked EPSPs were characterized by much slower time courses than those from the nucleus interpositus.