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Biomedical subjects

R Iizuka

Publications and source records attributed to R Iizuka.

At least 109 records · Page 6Linked to original sources
PubMed1987

Self-priming effect of LH-RH on pituitary gonadotropins in hyperprolactinemic women.

To investigate how various concentrations of serum prolactin (PRL) influence the priming effect of luteinizing hormone releasing hormone (LH-RH) on the pituitary gland, 24 women with various blood PRL concentrations received intravenous injections of 100 micrograms of synthetic LH-RH twice at an interval of 60 minutes and their serum LH and follicle-stimulating hormone (FSH) were measured and analysed. In the follicular phase with a normal PRL concentration (PRL less than 20 ng/ml, n = 6), marked first peaks of the two hormones following the first LH-RH stimulation and enhanced second peaks after the second LH-RH administration were observed, indicating a typical priming effect of LH-RH on gonadotropins, though the second response of FSH was more moderate than that of LH. In hyperprolactinemia, in which the serum PRL concentration was higher than 70 ng/ml (n = 13), the basal concentration of gonadotropins was not significantly changed but the priming effect of LH-RH on LH and FSH was significantly decreased (p less than 0.01). No marked second peaks of LH and FSH were observed, suggesting an inhibitory effect of hyperprolactinemia on the second release of LH and FSH. In contrast, this effect was restored in a group of women whose serum PRL concentration was between 30 and 50 ng/ml (n = 5). Furthermore, enhanced second peaks of both LH and FSH were noted after successful bromocriptine therapy reduced hyperprolactinemia (PRL greater than 70 ng/ml) to less than 25 ng/ml (n = 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Continuous-step density gradient centrifugation for the selective concentration of progressively motile sperm for insemination with husband's semen.

To increase the fertilizability of sperm for use in artificial insemination with husband's semen, it is effective to concentrate progressively motile sperm from whole ejaculated semen. The simple procedure, a continuous-step density gradient technique, was developed to selectively concentrate progressively motile sperm. The ejaculated semen was placed on 6.0 ml of 80% Percoll solution, and the density gradient was formed by mixing the semen and Percoll with an L-shaped rod for two or three strokes. After centrifugation at 400 x g for 30 min, progressively motile sperm were concentrated in the sediment, whereas the immotile sperm and other types of cells remained in the upper part of the density gradient. In most specimens sperm motility was improved by more than 80% regardless of the original motility. Thus, the fertility index (sperm concentration/ml x percentage of motility x 10(-8)). was increased to 7.7 +/- 3.7 times (n = 15).

Centrifugation, Density Gradient↗
PubMed1987

Effects of gradient centrifugation on human sperm.

The quality of ejaculated human sperm was examined for 24 h at room temperature by Percoll continuous density gradient centrifugation. One hour after ejaculation, apparent densities of good motile sperm with normal morphology were above 1.10 g/ml, whereas those of immotile and/or immature sperm recovered from upper layers were 1.06-1.09 g/ml. As time passed, sperm became immotile and the number of sperm with higher densities was diminished, their density shifting to 1.06-1.09 g/ml. Morphological observations by transmission electron microscope showed that after 24 h the sperm with higher densities were morphologically normal, except that the plasma membrane and the outer acrosomal membrane were lost. On the other hand, the sperm with lower densities were abnormal, such as immature, without the outer and the inner acrosomal membrane, with the nuclear decondensation, and with membraneous structure in the nucleus. These results suggest that after ejaculation the apparent density of human sperm became lower, concomitant with the loss of motility.

Centrifugation, Density Gradient↗
PubMed1987

Funnel procedure to separate human sperm with good motility.

Penetration of human sperm into a underlaying Percoll layer is very effective in isolating forward motile sperm. A plastic funnel, the bottom of which having been plugged with a 1.0-ml disposable syringe, was used as a separation vessel. Ejaculated semen (2.0 ml) was loaded on 2.0 ml of 80% Percoll; after allowing to stand 60 min, forward motile sperm penetrating into the lower part of Percoll layer (1.0 ml) were collected into the syringe. Sperm motility was enhanced to 91.5% +/- 3.3% regardless of the original motility (48.4% +/- 14.6%) with a mean recovery of 34.1% +/- 6.8% (n = 22). Measurement of residual lactate dehydrogenase activity suggested that seminal plasma was excluded almost completely from the purified sperm fraction.

Cell Separation↗
PubMed1987

Buoyancy and sedimentation of human X- and Y-bearing sperm.

The buoyant and sedimentation behaviors of human X- and Y-bearing sperm were examined in discontinuous density gradients of Nycodenz. The washed sperm placed at the bottom of the discontinuous density gradients of Nycodenz (23-50% in 3% steps) were centrifuged at 250 x g for various periods. The buoyant velocity of X-bearing sperm was faster than that of Y-bearing sperm. The sedimentation profiles of human sperm in the discontinuous density gradients of Nycodenz (4-20% in 2% steps) showed that X-bearing sperm sedimented faster than Y-bearing sperm. The separation of X- and Y-bearing sperm by means of centrifugation usually have been based on the assumption that smaller Y and larger X chromosomes might provide the difference in their apparent densities. The present results suggest that the separation cannot be due merely to a difference in their densities.

Cell Separation↗
PubMed1987

Sialic acid in purified human sperm.

Sialic acid levels of human sperm were estimated using newly developed sperm purification procedure (inner column method). This was used to estimate net sialic acid content of forward motile sperm of normal morphology without any contamination of the seminal plasma, other cellular components, and immature or abnormal sperm. The sialic acid content in purified sperm was approximately 40% of that in the washed (dilution-washing method) sperm. It is suggested that biochemical properties of human sperm should be reevaluated using the inner column purification procedure.

Cell Separation↗
PubMed1987

[Ovulation induction with a combination of LHRH analogue and hMG pulsatile subcutaneous administration in PCO patients].

The pulsatile subcutaneous administration of hMG (hMG therapy) and treatment with a combination of luteinizing hormone releasing hormone analogue (Buserelin) and hMG (combined therapy) were used to induce ovulation in 9 patients with polycystic ovary syndrome (PCO). Ovulation was observed in all twelve treatment cycles in the combined therapy, and two cases (delivery at term, and abortion) of pregnancy were confirmed. In the hMG therapy, ovulation occurred in 22 cycles of 26 treatment cycles. Ovarian hyperstimulation occurred in one cycle in the combined therapy and in 5 cycles (3 ovulated patients) in the 26 hMG therapy. The total dose per cycle of hMG required to induce ovulation in the combined therapy (1,700 +/- 203IU) was significantly lower than in the hMG therapy (2,344 +/- 223IU). In response to Buserelin administration, LH and FSH increased transiently and then declined to the normal range observed in the early follicular phase. The reduced LH level was sustained throughout the hMG administration. The concentration of FSH increased in response to hMG administration, resulting in a change in the LH/FSH ratio. The LH/FSH ratio in the combined therapy was significantly lower than in the hMG therapy. The present data demonstrated that pulsatile subcutaneous administration of hMG associated with Buserelin was effective in inducing ovulation in patients with PCO with a low incidence of serious side effects.

Administration, Intranasal↗
PubMed1987

[Production of monoclonal antibody against a newly established human endometrial cancer cell line SNG-II].

A cell line designated SNG-II was established from the operation specimen of human endometrial adenocarcinoma, and by means of an immunization procedure using intact SNG-II cells, a monoclonal antibody (Mab) named MSN-1 which reacts immunohistochemically with endometrial cancers was obtained. The cell line grew well without interruption for over 5 years, and, SNG-II cells produced tumors of cell differentiated adenocarcinoma in nude mice. The modal chromosomal number was diploid without a marker chromosome. The production of human chorionic gonadotropin and its beta-subunit, CA-125, tissue polypeptide antigen, and placental proteins such as PP6 and PP7 in SNG-II was confirmed. MSN-1 was of IgM subclass. As the antigenic reactivity was unchanged by trypsin treatment, but lost by periodic treatment, it was suggested that the antigen corresponding to MSN-1 was a carbohydrate sequence. Immunohistochemically MSN-1 reacted with about 70% cases of endometrial adenocarcinoma, but seldom with normal endometrium. Furthermore, the staining pattern of MSN-1 was different in benign cells from that in malignant cells: only the luminal surface of the normal endometrium was positive, whereas the cytoplasma was also stained in many of adenocarcinoma cells.

Adenocarcinoma↗
PubMed1987

[Physiological significance of the self-priming effect of LH-RH on the anterior pituitary glands].

To investigate the intracellular mechanisms of the self-priming effect of LH-RH on the anterior pituitary gland, the responses of pituitary and serum gonadotropins to two administrations of this decapeptide at a 60 min, interval were studied in male rats. A clearly recognized self-priming effect in male rats was significantly suppressed by the administration of RNA synthesis inhibitor. Although the pituitary LH content decreased significantly after the first administration, the content increased to the control level immediately before the second administration. This recovery was prevented by the administration of RNA synthesis inhibitor. In spite of the large second response, the rate of the second LH depletion was low. The number of secretory granules in gonadotrophs showed similar changes to the pituitary LH content. The dilatation of the Golgi apparatus was observable at 60 min. after the first administration. These results of rat experiments indicate that the second response includes the newly synthesized gonadotropins, and a clinical LH-RH two step test could be employed to evaluate both pituitary gonadotropin synthesizing and secreting functions.

Animals↗
PubMed1987

The characteristics of luteinizing hormone and its beta-subunit secretion in dispersed rat anterior pituitary cells.

Secretion of luteinizing hormone (LH) and its beta-subunit (LH-beta) by luteinizing hormone-releasing hormone (LH-RH) were studied in perifused rat anterior pituitary cells. LH release was dose related between 10(-10) and 10(-6)M LH-RH. Every 5-minute pulse of 10(-8)M LH-RH induced almost similar response to the initial LH release; neither the self-priming effect nor desensitization were significant. Continuous administration of 10(-8)M LH-RH caused an initial LH release, followed by distinct desensitization, which could not be overcome by subsequent pulses of 10(-8)M LH-RH. The results were quite similar in LH-beta release. The perifusion study is shown to be useful in analyzing the characteristics of LH and LH-beta release, and the present results suggest that LH-RH receptor-mediated regulation may be also involved in LH-beta release.

Animals↗
PubMed1987

[Establishment and characteristics of a new human choriocarcinoma cell line and its production of tumor markers].

A human gestational uterine choriocarcinoma cell line (NJG) was established in vitro. The NJG cell line had been subcultured more than 73 times over 7 years. The cells consisted mainly of Langhans-like cells, while multinucleated cells were occasionally seen. The cells grew in a monolayered sheet, showing a tendency to pile up, with the population doubling in 80 hrs. Electron-microscopically, desmosomes were characteristically observed, which suggested that the cultured cells were of epithelial origin. Chromosomal analysis revealed aneuploidy with a hypertriploid mode and 4 marker chromosomes. Immunocyto- and-histochemical staining for tumor markers of the cultured cells and the transplanted tumors to nude mice showed close similarity. SP1 was occasionally demonstrated and PP5 was faintly stained only in the heterotransplanted tumors, although PP10 and PP12 were not demonstrable. HCG was localized not only in syncytial cells, but also in Langhans cells, and syncytial cells without hCG were also observed in the tumors. A single cell clone was also established from the original NJG cells by a limiting dilution method. The heterotransplanted tumor consisted of Langhans and syncytial cells, indicating that both cells originated from the same cell.

Animals↗
PubMed1987

[Follow-up study of children born following immunization therapy for habitual abortions].

A follow up study was carried out on 24 children whose mothers were treated with HLA immunization as therapy for habitual abortion. Among 350 couples who had experienced recurrent spontaneous abortions registered at this clinic, 117 women were immunized with their husbands' leucocytes. Seventy became pregnant and so far 24 have delivered. The sex ratio of the babies was 16 males to 8 females. The average body weight and height at birth were 3,294 +/- 88.5 g (mean +/- S.E., male) and 3,079 +/- 114.4 g (female), 50.0 +/- 0.38 cm (male) and 49.0 +/- 0.60 cm (female), respectively. Average gestational duration was 39.0 +/- 0.23 weeks and mean labor hours were 7.0 +/- 0.73 without any complication except two cesarean sections. Four out of 24 children were more than 2 years old and 12 were less than one year old. All of them were interviewed or investigated by questionnaires on the developments of body weight, height, sensory organs as well as dental development after birth. Emotional and other physical developments and history of disease after the neonatal period were also examined. Though basic immunological studies will be required in future, all investigations indicate that no abnormal sign normal developments were found in these children, indicating further application of this therapy for habitual abortion.

Abortion, Habitual↗
PubMed1986

Cooperative inhibitory effect of follicular fluid and cAMP on hamster oocyte maturation.

Porcine or human follicular fluid inhibited the spontaneous maturation of isolated hamster oocytes in vitro during the first 1.5 h of culture. Moreover, the presence of 50% follicular fluid combined with 100 microM dbcAMP cooperatively reduced the incidence of germinal vesicle breakdown. The addition of FSH also inhibited the resumption of meiosis, and the presence of LH did not overcome the inhibitory effects of follicular fluid and tended to impede isolated hamster oocyte maturation in vitro.

Animals↗
PubMed1986

Extrahypophyseal distribution of alpha-melanocyte stimulating hormone (alpha-MSH)-like immunoreactivity in postmortem brains from normal subjects and Alzheimer-type dementia patients.

Using a sensitive double-antibody solid-phase enzyme immunoassay method alpha-melanocyte stimulating hormone-like immunoreactivity (alpha-MSH-LI) was measured in 21 regions of postmortem brains from 8 normal subjects and 5 patients with Alzheimer-type dementia (ATD). In the brains from the normal subjects, the highest concentration of alpha-MSH-LI was found in the hypothalamus. Relatively high concentration were also measured in the locus coeruleus, substantia innominata, substantia nigra, amygdala and medial nucleus of thalamus. alpha-MSH-LI in other regions was approximately 1/100 of the hypothalamic content. This data is consistent with the existence of alpha-MSH in extrahypophyseal regions and indicates its regional distribution in the human brain. In the Alzheimer brains, although the temporal cortex and hippocampus had normal concentrations of alpha-MSH-LI, the cingulate cortex, caudate and substantia nigra showed significantly lower concentrations of alpha-MSH-LI than those of the control brains. This data suggests that further studies of alpha-MSH content in a larger number of ATD brains would be useful.

Aged↗
PubMed1986

Regional distribution of amino acid transmitters in postmortem brains of presenile and senile dementia of Alzheimer type.

We measured the concentrations of glutamate, aspartate, and gamma-aminobutyrate (GABA) in cortical and subcortical areas by an enzymatic fluorometric method in 9 patients with histologically verified Alzheimer's disease and senile dementia of the Alzheimer type (AD/SDAT), and in 10 age-matched normal control subjects. When compared with controls, the concentration of glutamate in cortical and subcortical areas of AD/SDAT brains was significantly reduced. The concentrations of aspartate and GABA were also reduced in several areas, but the magnitude of reduction was less than that of glutamate. This apparent reduction of glutamate in postmortem brains might have a bearing on pathophysiological mechanisms in AD/SDAT.

Aged↗
PubMed1986

Morphological and biochemical changes in the cholinergic and monoaminergic systems in Alzheimer-type dementia.

The integrity of cholinergic and monoaminergic neuronal systems in Alzheimer-type dementia (ATD) was studied using a combination of morphological and biochemical procedures applied to samples from seven ATD brains and ten control brains. On morphological examination, the number of neurons was counted in the nucleus basalis of Meynert (nbM), the locus coeruleus (LC) and the nucleus centralis superior (NCS). Biochemically, the activities of choline acetyltransferase (ChAT) and the concentrations of noradrenaline (NA) and serotonin (5-hydroxytryptamine; 5-HT) were measured in the nbM, LC, NCS, frontal cortex, temporal cortex and occipital cortex. Compared with the controls, the mean number of neurons in the nbM and LC were significantly reduced in the ATD brains. The neuronal loss in the NCS in the ATD brains was not significant. The ChAT activities in all regions from the ATD brains had a tendency to be reduced. Marked reductions in the NA concentrations in the LC and 5-HT concentrations in the temporal and occipital cortices were found in the ATD brains. These findings suggest that various neurotransmitter systems, including cholinergic, noradrenergic and serotonergic systems, are affected in the ATD brains.

Aged↗