A stroke patient with impairment of auditory sensory (echoic) memory.

A 42-year-old man suffered damage to the left supra-sylvian areas due to a stroke and presented with verbal short-term memory (STM) deficits. He occasionally could not recall even a single syllable that he had heard one second before. A study of mismatch negativity using magnetoencephalography suggested that the duration of auditory sensory (echoic) memory traces was reduced on the affected side of the brain. His maximum digit span was four with auditory presentation (equivalent to the 1st percentile for normal subjects), whereas it was up to six with visual presentation (almost within the normal range). He simply showed partial recall in the digit span task, and there was no self correction or incorrect reproduction. From these findings, reduced echoic memory was thought to have affected his verbal short-term retention. Thus, the impairment of verbal short-term memory observed in this patient was "pure auditory" unlike previously reported patients with deficits of the phonological short-term store (STS), which is the next higher-order memory system. We report this case to present physiological and behavioral data suggesting impaired short-term storage of verbal information, and to demonstrate the influence of deterioration of echoic memory on verbal STM.

Sudden hearing loss following drip intravenous pyelography with iohexol: a case report.

A 37-year-old male developed severe sensorineural hearing loss (SNHL) following drip intravenous pyelography with iohexol. We suggest that this hearing disturbance might have been caused by a delayed allergic reaction to iohexol or to its toxicity, because hearing loss developed several hours after the infusion of iohexol. No improvement in hearing was achieved after various treatments. This is the first report of SNHL possibly attributable to the adverse effects of iohexol.

Characteristic distribution of HTLV type I and HTLV type II carriers among native ethnic groups in South America.

To confirm the geographic and ethnic segregation of HTLV-I and HTLV-II carriers in native populations in South America, we have conducted a seroepidemiological study of native populations in South America, including HTLV-I carriers distributed among seven ethnic groups in the Andes highlands of Colombia, Peru, Bolivia, Argentina, and Chile, and two ethnic groups on Chiloe Island and Easter Island; and HTLV-II carriers distributed among seven ethnic groups of the lowlands along the Atlantic coast of Colombia, Orinoco, Amazon, and Patagonia, and one ethnic group on Chiloe Island. The incidence rate of HTLV-I and HTLV-II carriers varied among the ethnic groups, ranging from 0.8 to 6.8% for HTLV-I seropositivity and from 1.4 to 57.9% for HTLV-II seropositivity. A new HTLV-I focus was found among the Peruvian Aymara (1.6%), the Bolivian Aymara (5.3%) and Quechua (4.5%), the Argentine Puna (2.3%), and the Chilean Atacama (4.1%), while on HTLV-II focus was found among the Brazilian Kayapo (57.9%), the Paraguayan Chaco (16.4%), and the Chilean Alacalf (34.8%) and Yahgan (9.1%). The distribution of HTLV-I/II foci showed a geographic clustering of HTLV-I foci in the Andes highlands and of HTLV-II foci in the lowlands of South America. It was thus suggested that South American natives might be divided into two major ethnic groups by HTLV-I and HTLV-II carrier state.

Transcriptional and post-transcriptional regulation of FSH receptor in rat granulosa cells by cyclic AMP and activin.

The effect of FSH on the induction of FSH receptors in granulosa cells is believed to be mediated, at least in part, by the cAMP second messenger system. We examined the effect of activin and cAMP on FSH receptor expression in this culture system. Steady-state levels of FSH receptor mRNA, analyzed by Northern blot hybridization, increased 3.5-fold in response to 24-h incubation with activin and 1.7-fold with 12-h incubation with 8-bromoadenosine 3,5-cyclic monophosphate (8-Br-cAMP; 0.2 mM). We have investigated whether 8-Br-cAMP- and/or activin-induced increases in FSH receptor mRNA levels are the result of increased transcription and/or altered mRNA stability. The rates of FSH receptor mRNA gene transcription, assessed by nuclear run-on transcription assay, increased 3-fold in cells treated with activin and 1.5-fold in cells treated with 8-Br-cAMP for 2 h. To examine the degradation rates of FSH receptor mRNA transcripts, granulosa cells were preincubated with 8-Br-cAMP, activin, or medium alone for 6 h. After the preincubation period, 5 microM actinomycin-D or 200 microM 5,6-dichloro-1-beta-ribofuranosyl benzimidazole were added to arrest new RNA synthesis. The decay curves for the 2.4 kb FSH receptor mRNA transcript in granulosa cells were not significantly different in the absence or presence of 8-Br-cAMP. Activin, on the other hand, significantly altered the slope of the FSH receptor mRNA decay curve and increased the half-life of the 2.4 kb FSH receptor mRNA transcript. These data provide evidence that cAMP induces FSH receptor mRNA levels by stimulating the transcription rate and that activin increases FSH receptor mRNA levels both by stimulating transcription rates and by stabilizing the FSH receptor mRNA transcripts.

Regulation of midkine messenger ribonucleic acid levels in cultured rat granulosa cells.

To investigate the regulation of ovarian midkine (MK) production at the mRNA level, we evaluated changes in MK mRNA in cultured granulosa cells. The level of MK mRNA increased in a time-dependent manner in the presence of FSH or retinoic acid (RA). FSH increased MK mRNA levels in a dose-dependent manner to a maximum of about 2-fold increase. The stimulatory effects of FSH were mimicked by 8-Br-cAMP. RA increased MK mRNA levels in a dose dependent manner to a maximum of about 2 fold increase at a concentration of 0.3 microM. These results show that granulosa cells produce MK mRNA under the independent control of FSH and RA. The coexistence of FSH and RA in this culture exerted no additive effect on the induction of MK mRNA. Analysis of FSH receptor mRNA induction by both reagents revealed that FSH stimulated expression of the FSH receptor while RA had an inhibitory effect on FSH receptor induction regardless of the presence of FSH. These data show that RA increases MK mRNA, and decreases FSH receptor expression, by a pathway independent of cAMP.

Regulation of follicle-stimulating hormone receptor.

The acquisition of follicle-stimulating hormone (FSH) receptors during folliculogenesis is believed to be a key event in follicle development. We have examined the effects of FSH and activin on FSH receptor mRNA in cultured rat granulosa cells. Treatment of granulosa cells with FSH resulted in transient suppression of the FSH receptor mRNA levels 2-6 h after treatment, with subsequent recovery at 24 h. We could not detect a similar effect on FSH receptor mRNA by 8-bromoadenosine 3,5-cyclic monophosphate, which continuously stimulated FSH receptor mRNA over a similar time course. On the other hand, stimulation of the protein kinase C (PKC) pathway with phorbol myristate acetate mimicked the time course of the effects of FSH on the levels of FSH receptor mRNA. Taken together, these results suggest that the cAMP cascade may increase the mRNA levels of FSH receptor and, at the same time, the other cascade, PKC, may decrease FSH receptor mRNA levels. To further investigate the role of activin in the regulation of granulosa cell function, we studied the effect of activin on FSH receptor mRNA levels. Compared to the control, treatment with activin (100 ng/ml) increased FSH receptor mRNA in a time-dependent manner with a maximum circa 4-fold increase at 24 h. Treatment of granulosa cells with activin (20-300 ng/ml) for 24 h increased FSH receptor mRNA in a dose-dependent manner to a maximum circa 4-fold increase at concentrations of 100-300 ng/ml. Although follistatin alone had no detectable effect on FSH receptor mRNA levels, combination of follistatin (0-200 ng/ml) with activin (100 ng/ml) caused a significant reduction in the levels of activin-induced FSH receptor mRNA in a dose-dependent manner.

Application of Chinese hamster ovary cells transfected with the recombinant human follicle-stimulating hormone (FSH) receptor for measurement of serum FSH.

OBJECTIVES: To evaluate the activity of the serum FSH bioactivity in patients with premature ovarian failure (POF). DESIGN: Prospective study. SETTING: Infertility and gynecology outpatient clinics at the Gunma University School of Medicine, Gunma, Japan. PATIENTS: Twelve women, aged 27 to 39 years, with POF and nine postmenopausal women. INTERVENTIONS: Serum samples obtained from postmenopausal women and POF patients. The immunoglobulin (Ig)G fractions of some sera from POF patients were prepared by 20% polyethylene glycol. MAIN OUTCOME MEASURES: Serum samples were measured simultaneously by the bioassay system and immunoradiometric assay (IRMA). RESULTS: The bioassay values correlated with those obtained by IRMA, and the correlation coefficient and the slope of the regression lines calculated from nine pairs of assay values from the postmenopausal women were 0.867 and 1.10, respectively. The mean of the biologic:immunologic ratios of sera from postmenopausal women and POF patients were 1.44 and 1.25, respectively. CONCLUSIONS: The IgG fractions of some sera from POF patients showed stimulatory or inhibitory effect on cyclic adenosine 3':5' monophosphate production compared with that from postmenopausal women. These results may reflect the more complex pathophysiological states of the patients with POF.

Regulation and localization of midkine in rat ovary.

In a previous experiment, it was shown that midkine (MK) was quite abundant in the follicular fluid; the concentration of MK in bovine follicular fluid was estimated to be 125 micrograms/l. To investigate the regulation of MK production in the ovary, we examined the effect of pregnant mare's serum gonadotropin (PMSG) and PMSG-hCG treatment on the expression of MK in rat ovary. The mRNA of midkine (MK) was increased by PMSG injection and decreased by PMSG and hCG injection; the profile of change of mRNA of MK was similar to that of FSH receptor. Using in situ hybridization, we observed that the MK mRNA localized to granulosa cells. These results suggest that the granulosa cells produce MK under the control of gonadotropin.

Regulation of follistatin messenger ribonucleic acid in cultured rat granulosa cells.

The regulation of the follistatin mRNA by hormones and endocrine manipulations was examined in granulosa cell cultures. The follistatin mRNA accumulation was stimulated in a dose-dependent manner by follicle-stimulating hormone (FSH) with a maximal response twice as great as in control cultures at a dose of 100 ng/ml FSH. The time course of the FSH effect on follistatin mRNA had a biphasic effect in which FSH increased follistatin mRNA within 2 h, and subsequently reduced it to below the control level. 8-Br-8 brom-adenosine 3,5-cyclic monophosphate (cAMP) (2 mM) and phorbol 12-myristate 13-acetate (PMA) (10 nm) induced a time-dependent increase in follistatin mRNA levels, with the maximal response at 6 h and 2 h, respectively. Co-treatment of the granulosa cells with cAMP and PMA demonstrated that 0.2 mM of 8-Br-cAMP suppressed the follistatin mRNA of the control and the samples with a small amount of PMA in the granulosa cells. Follistatin expression is therefore regulated by protein kinase A and protein kinase C pathways in rat granulosa cells. A more dramatic stimulation of follistatin mRNA was observed when this culture was treated with activin, and follistatin also blocked the effect of activin on the follistatin mRNA.

Regulation of follicle-stimulating hormone receptor messenger ribonucleic acid levels in cultured rat granulosa cells.

The acquisition of follicle-stimulating hormone (FSH) receptors during follicogenesis is believed to be a key event in the subsequent development of the follicle. We have examined the effect of FSH on FSH receptor mRNA in cultured rat granulosa cells by means of FSH receptor cRNA probe. Northern blot analysis indicated the existence of two predominant FSH receptor mRNA transcripts of approximately 5.5 and 2.4 kb in total RNA prepared from rat granulosa cells. Treatment of granulosa cell culture with FSH resulted in tentative suppression of FSH receptor mRNA level 2-6 h after treatment, with subsequent recovery at 24 h. Culture of granulosa cells for 6 h in the presence of increasing concentration of FSH resulted in a dose-dependent decrease in FSH receptor mRNA with a maximal suppression about 50% of control observed in response to 100 ng/ml FSH. We could not detect a similar effect on FSH receptor mRNA by 8-brom-adenosine 3,5-cyclic monophosphate (8-Br-cAMP; 0.2 mM) which showed continuous stimulation on FSH receptor mRNA during a similar time course. In this system, therefore, this transient down-regulation of FSH mRNA was not mediated by the cAMP pathway. Since the inhibitory effect of follistatin on activin-induced FSH binding to rat granulosa cells had been investigated, we studied the action of follistatin on the levels of activin-induced FSH receptor mRNA in rat granulosa cell culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Microinjection of immaturin rejuvenates sexual activity of old Paramecium.

The sexual activity of aged Paramecium that underwent about 700 fissions after conjugation was remarkably decreased. Microinjection of a soluble cytoplasmic fraction prepared from young immature cells (about 20 fissions after conjugation) restored the sexual activity of the aged cells to that of presenescent mature cells. The factor responsible for the recovery of the sexual activity was shown to have the same characteristics as immaturin in terms of molecular size and net charge. Rejuvenation of sexual activity lasted up to 20 fissions after microinjection. However, cell division rate or fertility after self-conjugation was not increased by the microinjection. Our finding indicates that the decrease in sexual activity caused by aging was not due to defects in the genes for mating substances but to a decrease in the activity of a soluble protein responsible for the expression of mating activity. This is the first description of the restoration of a senescent defect by microinjection of young cytoplasmic components into Paramecium.

Resistance of germinal nucleus to aging in Paramecium: evidence obtained by micronuclear transplantation.

A diversity of time when increase in mortality after conjugation occurs during the lifespan was found in subclones of three stocks of Paramecium caudatum. A possible micronuclear contribution to the increase in sterility has been investigated by micronuclear transplantation. We found two classes of micronuclei in aged clones: those that can function normally if the cytoplasmic environment is young, and those that cannot, even in a young cytoplasmic environment. The results indicate that in the former, the age-dependent increase in sterility is due to a deleterious macronucleus and/or cytoplasm, and in the latter it is due to micronuclear damage. The micronuclear damage in aged clones is probably induced by a deleterious cytoplasmic environment because aged clones with transplanted young micronuclei showed an abrupt decrease in progeny survival between 14 and 42 cell divisions after transplantation. Overall, the micronucleus seems not to be a source of age-related damage but rather is subjected to damage from macronuclear and/or cytoplasmic sources.