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PubMed1986

An electron microscopic study of nucleolus-organizing regions at some stages of the cell cycle (G0 period, G2 period, mitosis).

Nucleolus-organizing regions (NORs) at some stages of the cell cycle (G0 period, G2 period and mitosis), differing in the level of NOR transcription activity, were studied on ultra-thin serial sections of pig embryo kidney cells. Particular attention was given to the spatial organization of fibrillar centers (FCs) in the nucleoli and to comparing the number of FCs with that of NORs. It was shown that within nucleoli, FCs may be located singly or form groups surrounded by a dense fibrillar component. The overall number of FCs exceeds that of NORs 1.7-fold in the G0 period, and 4.6-fold in the G2 period. At prophase, with progressive condensation of chromosomes and NOR inactivation, the number of FCs decreases and at metaphase corresponds to the number of silver-stained NORs. The data thus obtained make it possible to conclude that in active nucleoli, the number of FCs is higher than that of NORs. Proceeding from these numerical and ultrastructural data, it is suggested that a single NOR of pig embryo kidney cells corresponds to one "fibrillar complex", i.e., to an association of a different number of FCs with the dense fibrillar component. These "fibrillar complexes" contain 1 to 3 FCs in the G0 period and 1 to 12 FCs in the G2 period.

Animals↗
PubMed1985

A prospective multicentre study to develop universal immunochemical tests for predicting the fertile period in women. World Health Organisation Task Force on Methods for the Determination of the Fertile Period, Special Programme of Research, Development and Research Training in Human Reproduction.

Two immunochemical tests for predicting the fertile period have been adapted for application throughout the world. The estrone test involves the measurement of estrone-3-glucuronide (E1-3-G) in daily samples of early morning urine. The start of the fertile period is identified by a sustained rise in the concentration of E1-3-G (as determined by cumulative sum analysis); the end of potential fertility occurs 120 hours (5 days) after the peak level. Alternatively, the ratio of E1-3-G to pregnanediol-3 alpha-glucuronide (Pd-3 alpha-G) can be calculated and the fertile period identified between a defined rise in this index and the peak value plus 144 hours (6 days). One hundred thirty-one women from 10 countries provided samples from 557 menstrual cycles, and the results from 455 (82%) were accepted for statistical analysis. There were highly significant differences (P less than 0.0001) in the concentrations of the metabolites between centres, but the time intervals between both the rise and peak days and the day of the luteinizing hormone (LH) peak were less significantly different (P less than 0.05) for the estrone test and not significantly different for the ratio test. The fertile period was defined as the day of the LH peak -3 to the day of the LH peak +2. The estrone test successfully delineated this phase in 78% of menstrual cycles, and the ratio test, in 74%. The mean lengths of the derived fertile periods by both methods were 9.3 (SD 2.3) and 10.0 (SD 2.4) 24-hour periods (or days), respectively.

Adult↗
PubMed1994

Period dependent selection in continuous culture of viruses in a periodic environment.

Selection in a cellstat culture of two mutant strains of a bacteriophage under periodically fluctuating temperature was analyzed mathematically and numerically. Each of the two viral strains (P1 and P2) was assumed to have a different Arrhenius activation energy for its reproduction reaction. A phase diagram of the final state in the continuous culture was drawn. The most noticeable was that there were both P1-only and P2-only phases of competitive exclusion depending on the period of oscillation and the dilution rate. The period-dependent selection was proved that it was based on the feedback effect via the host-population change. At a short period of oscillation, the strain with larger arithmetic average fitness ultimately dominated in the population; on the other hand, at a long period of oscillation, the strain with larger geometric average fitness ultimately dominated. There was a co-existence phase between the two exclusion phases. The results suggest the feasibility of a method to escape from trapping at local optima on a fitness landscape in evolutionary molecular engineering.

Bacteriophages↗
PubMed1987

On periodic responses generated by a degenerate analog neuron model with periodic inputs.

Periodic responses to periodically varying stimulating pulse sequences are mathematically described for a degenerate analog neuron model. The model used was derived by Yoshizawa et al. (1982) in their investigation of the state transition of an electronic model using a tunnel diode in a degenerate case. Periodic responses to constant pulse sequences for the model were described by them. In this paper, it is shown that periodic responses to periodically varying pulse sequences for the model are identical with those which the author previously described for a discrete neuron model.

Mathematics↗
PubMed1982

The measurement of urinary steroid glucuronides as indices of the fertile period in women. World Health Organization, Task Force on Methods for the Determination of the Fertile Period, special programme of research, development and research training in human reproduction.

The concentrations of various estrogen glucuronides and pregnanediol-3 alpha-glucuronide have been measured in daily samples of early morning urine (EMU) and 24 h pooled collections throughout a total of 70 menstrual cycles (58 subjects). The immediate objective was to identify and assess the potential value of measuring hormone metabolites to locate the fertile period in women, with the ultimate aim of developing a non-invasive immunochemical test. The project was undertaken in five centres and the results showed that: (i) there was good agreement in the patterns and mean concentrations of metabolites between the centres; (ii) estrone-3-glucuronide should be the estrogen glucuronide selected for further study; (iii) the analysis of EMU provided information that was as useful as the corresponding measurements on pooled collections for 24 h; (iv) a rise in the concentration of estrone-3-glucuronide (50% over the mean of three preceding values) could be used to locate the start of the fertile period in greater than 90% of the ovarian cycles (from day LHmax -- 3 to day LHmax -- 7); attempts to locate the end of the fertile period by a threshold value or a defined rise in the level of pregnanediol-3 alpha-glucuronide were disappointing. A 50% rise over the mean of three preceding values in the derived concentration ratio of estrone-3-glucuronide/pregnanediol-3 alpha-glucuronide could be used to indicate the start of the fertile period, and a 50% decrease plus two days the start of the infertile period in greater than 80% of the ovarian cycles. The limitations, implications and future developments are discussed.

Adolescent↗
PubMed2005

Tumor necrosis factor receptor-associated periodic syndrome in a young adult who had features of periodic fever, aphthous stomatitis, pharyngitis, and adenitis as a child.

Tumor necrosis factor receptor-associated periodic syndrome (TRAPS) was diagnosed in a 22-year-old man after a 1-year history of periodic fever, myalgia, conjunctivitis, cervical lymphadenopathy, and oral ulcers. As a child he had signs and symptoms suggestive of periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome. This report indicates the importance of considering TRAPS as a cause of periodic fever in older children and adults and that TRAPS may present with signs and symptoms suggestive of periodic fever, aphthous stomatitis, pharyngitis, and adenitis syndrome in young children.

Adult↗
PubMedDate not supplied

Suitability of acoustic perturbation measures in analysing periodic and nearly periodic voice signals.

In recent years, acoustic perturbation measurement has gained clinical and research popularity due to the ease of availability of commercial acoustic analysing software packages in the market. However, because the measurement itself depends critically on the accuracy of frequency tracking from the voice signal, researchers argue that perturbation measures are not suitable for analysing dysphonic voice samples, which are aperiodic in nature. This study compares the fundamental frequency, relative amplitude perturbation, shimmer percent and noise-to-harmonic ratio between a group of dysphonic and non-dysphonic subjects. One hundred and twelve dysphonic subjects (93 females and 19 males) and 41 non-dysphonic subjects (35 females and 6 males) participated in the study. All the 153 voice samples were categorized into type I (periodic or nearly periodic), type II (signals with subharmonic frequencies that approach the fundamental frequency) and type III (aperiodic) signals. Only the type I (periodic and nearly periodic) voice signals were acoustically analysed for perturbation measures. Results revealed that the dysphonic female group presented significantly lower fundamental frequency, significantly higher relative amplitude perturbation and shimmer percent values than the non-dysphonic female group. However, none of these three perturbation measures were able to differentiate between male dysphonic and male non-dysphonic subjects. The noise-to-harmonic ratio failed to differentiate between the dysphonic and non-dysphonic voices for both gender groups. These results question the sensitivity of acoustic perturbation measures in detecting dysphonia and suggest that contemporary acoustic perturbation measures are not suitable for analysing dysphonic voice signals, which are even nearly periodic.

Adult↗
PubMed1989

[Characteristics of the menstrual cycles during the postpartum period without breast feeding according to the nature of the first period: ovulatory or anovulatory].

The authors have analyzed the characteristics of menstrual cycles during the post-partum without breastfeeding, according to the nature of the first period. 172 women gave the thermal curve from childbirth to the first period. Among them, 118, 111, 98 and 54 women gave the self-observation data concerning, respectively, the first, second, third and the fourth cycle after the first period. They have noticed more short luteal phases and delays in ovulation after an anovulatory first period than after an ovulatory first period. The hormonal studies in the post-partum without breastfeeding seem not to explain the whole of these anomalies ascertained beyond twelve post-partum weeks. Most authors admit that the gonadotropin axis returns to a normal state within the fifth post-partum week. Because of the peculiar kinetics of follicle development, the ovary could be an important component of the "remnant effect of gestation", that is to say, of the delay of return to post-partum ovulation following the gestation state.

Adult↗
PubMed1978

[Electroencephalographic periodicity with asynchronous variations in period duration in both hemispheres following acute cerebral anoxia].

The periodicity of paroxysmal wave complexes in EEG after acute cerebral anoxia with special reference to the dynamics of period duration (alteration of Zeitmass) is described in case 20 hours before isoelectric tracing. The completely asynchronous feature of paroxysmal events within certain limits of period duration in both hemispheres is a rare condition. Late and pure cortical electrogenesis is suggested. Short and long EEG- periods in similar and different pathological processes and functional states are compared with respect to topography of lesions. Subcortical interactions and extraneuronal influences upon periodicty are discussed. The parameters "complex wave and periodicity" in EEG and the dynamics respectively are a matter of serial investigations for better understanding pathophysiology and prognostic value.

Acute Disease↗
PubMed1993

Periodic mother deprivation during the light period reversed the phase of serotonin N-acetyltransferase activity rhythm of the pineal gland in rat pups.

It has been reported that nursing mother rats can postnatally entrain the circadian rhythms of blinded rat pups, such as locomotor, drinking, and corticosterone rhythms. To gain more insight in the mechanism of the postnatal entrainment of such pups' circadian rhythms, we examined the serotonin N-acetyltransferase (NAT) activity rhythm in blinded rat pups subjected to periodic mother deprivation (PMD) in which mothers were periodically deprived of their pups during either half of a day. We found that only PMD during the light period shifted the phase of NAT activity rhythm in the pups. To cause a reversal of the NAT activity rhythm, it was necessary to repeat PMD for more than 6 days. PMD for 6 h each day also shifted the phase of the blinded rat pups, but it did not reverse the NAT rhythm, even when it was repeated for 10 days. In 9-h deprivation for 10 days, however, deprivation during the first 9 h of the light period reversed the phase, although the latter 9 h failed to cause reversal of the phase. On the other hand, restricted feeding of the mother took more than 11 days to reverse the phase and a foster mother in the cross-fostering experiment failed to affect the phase of pup's rhythm, when the rhythm was determined on the 11th postnatal day. These facts indicate that PMD during the light period is a potent entrainer of the pups' circadian NAT rhythms and provide a useful method of exploring the underlying mechanism of the entrainment of the pups' rhythm by the mother.

Animals↗
PubMed2006

Spectrally similar periodic and non-periodic optic flows evoke different postural sway responses.

The present study investigated the effect of optic flow periodicity on postural sway. Head and center-of-pressure (COP) displacements in response to an oscillating full-field bullseye-and-checkerboard pattern were recorded in six healthy adults. Scene movement was driven by one of five signals: (1) 0.1 Hz sinusoid, (2) 0.3 Hz sinusoid, (3) 0.5 Hz sinusoid, (4) the periodic sum of these three sinusoids (PSUM), or (5) a non-periodic counterpart (NPSUM = 0.1+ pi/10 + 0.5 Hz). Sway response power at the various stimulus frequencies were compared: (1) among the three pure sinusoidal groups; and (2) between the two sum-of-sinusoid groups. Head and COP responses displayed similar spectral content, though sway magnitude was larger for the head. Sway responses to the moving scenes were significantly larger than those observed during quiet stance. Each sinusoidal moving scene evoked a strong response at the stimulus frequency, as well as increased sway at non-stimulus frequencies, primarily below 0.2 Hz. For the sum-of-sinusoids stimuli, both PSUM and NPSUM signals elicited sway responses at each of their component frequencies. The amplitudes of these responses were similar to one another at 0.1 and 0.3 Hz, but significantly different at 0.5 Hz, with PSUM responses on average four times larger than those for NPSUM. These findings indicate that spectrally similar periodic and non-periodic stimuli elicit quantitatively different sway responses. The observed behaviors may be due to postural sensitivity to the predictability of visual motion, or due to other nonlinear and/or time-varying mechanisms in the postural control system.

Adult↗
PubMed2003

Marked depression of time interval between fertilization period and hatching period following exposure to low-dose X-rays in zebrafish.

In recent years there has been growing concern over the stimulating effects of very low-dose X-rays. Our laboratory had observed that zebrafish irradiated with low-dose X-rays tended to emerge earlier than sham controls. This observation led us to quantitatively examine the effects of low-dose X irradiation on a series of stages of development in the zebrafish. The embryos were fertilized simultaneously in vitro and incubated at an optimal temperature without crowding. Following exposure of the cleavage period (1.5 h after fertilization) to 0.025-Gy X-rays, the duration to hatching was slightly shorter than that of the sham controls. This tendency was increased when the X-ray exposure occurred during the blastula period (3.5 h). In these embryos, the duration to hatching decreased significantly by an average of 6 h sooner than for sham controls. No differences in duration to hatching were seen when irradiation was given during either the zygote period (45 min) or the segmentation period (12 h). On the contrary, upon exposure to 0.5-Gy X-rays during the blastula period, the duration to hatching increased significantly relative to that of sham controls. These results suggest that the radiation-induced early hatching effect is observed for low doses of X-rays.

Animals↗
PubMed1999

Heart period and heart period variability during sleep on the MIR space station.

The long-term acclimation of cardiac rhythms to microgravity was studied in four astronauts aboard the Russian space station MIR during wakefulness and sleep. Sleep polygraphies were obtained between the third and the 30th day in space and, in addition, prior to mission on the ground. From each of the sleep polygraphies, beat-to-beat intervals of cardiac rhythms were determined. The response of heart period and heart period variability to the stimulus microgravity was tested during sleep across sleep stages and during waking. A lengthening of heart period by about 100 ms was found in space compared to measurements on the ground. The slowing of heart rate was more pronounced for non-REM sleep than for REM sleep. A systematic change in heart period in relation to the duration of the stay in space could not be detected. An analysis of heart period variability in the high frequency (respiratory sinus arrhythmia) band supports the hypothesis that the decrease of heart rate under microgravity is produced by an increase in parasympathetic activity. Testing the response of cardiac rhythms to microgravity across distinct behavioural states seems to be a powerful tool to investigate the cardiovascular system.

Adult↗
PubMed2001

The tumor-necrosis-factor receptor-associated periodic syndrome: new mutations in TNFRSF1A, ancestral origins, genotype-phenotype studies, and evidence for further genetic heterogeneity of periodic fevers.

Mutations in the extracellular domain of the 55-kD tumor-necrosis factor (TNF) receptor (TNFRSF1A), a key regulator of inflammation, define a periodic-fever syndrome, TRAPS (TNF receptor-associated periodic syndrome [MIM 142680]), which is characterized by attacks of fever, sterile peritonitis, arthralgia, myalgia, skin rash, and/or conjunctivitis; some patients also develop systemic amyloidosis. Elsewhere we have described six disease-associated TNFRSF1A mutations, five of which disrupt extracellular cysteines involved in disulfide bonds; four other mutations have subsequently been reported. Among 150 additional patients with unexplained periodic fevers, we have identified four novel TNFRSF1A mutations (H22Y, C33G, S86P, and c.193-14 G-->A), one mutation (C30S) described by another group, and two substitutions (P46L and R92Q) present in approximately 1% of control chromosomes. The increased frequency of P46L and R92Q among patients with periodic fever, as well as functional studies of TNFRSF1A, argue that these are low-penetrance mutations rather than benign polymorphisms. The c.193-14 G-->A mutation creates a splice-acceptor site upstream of exon 3, resulting in a transcript encoding four additional extracellular amino acids. T50M and c.193-14 G-->A occur at CpG hotspots, and haplotype analysis is consistent with recurrent mutations at these sites. In contrast, although R92Q also arises at a CpG motif, we identified a common founder chromosome in unrelated individuals with this substitution. Genotype-phenotype studies identified, as carriers of cysteine mutations, 13 of 14 patients with TRAPS and amyloidosis and indicated a lower penetrance of TRAPS symptoms in individuals with noncysteine mutations. In two families with dominantly inherited disease and in 90 sporadic cases that presented with a compatible clinical history, we have not identified any TNFRSF1A mutation, despite comprehensive genomic sequencing of all of the exons, therefore suggesting further genetic heterogeneity of the periodic-fever syndromes.

Alternative Splicing↗
PubMed2000

Periodic elastic medium in which periodicity is relevant

We analyze, in both (1+1) and (2+1) dimensions, a periodic elastic medium in which the periodicity is such that at long distances the behavior is always in the random-substrate universality class. This contrasts with the models with an additive periodic potential in which, according to the field-theoretic analysis of Bouchaud and Georges and more recently of Emig and Nattermann, the random manifold class dominates at long distances in (1+1) and (2+1) dimensions. The models we use are random-bond Ising interfaces in hypercubic lattices. The exchange constants are random in a slab of size L(d-1)xlambda and these coupling constants are periodically repeated, with a period lambda, along either 10 or 11 [in (1+1) dimensions] and 100 or 111 [in (2+1) dimensions]. Exact ground-state calculations confirm scaling arguments which predict that the surface roughness w behaves as w approximately L(2/3), L< >L(c) with L(c) approximately lambda(3/2) in (1+1) dimensions, and w approximately L0.42,L< >L(c) with L(c) approximately lambda(2. 38) in (2+1) dimensions.

Journal Article↗
PubMed1983

Medicare program; invalidation of the wage index in the schedule of limits on Hospital per diem inpatient general routine operating costs for cost reporting periods beginning on or after July 1, 1981 and ending with cost reporting periods beginning on or before September 30, 1982--HCFA. Notice.

This notice announces the April 29, 1983 decision of the United States District Court for the District of Columbia in the case of District of Columbia Hospital Association, et al. v. Heckler, et al. (No. 82-2520 D.D.C.). In its decision, the court ordered us to publish a notice in the Federal Register stating that the 1981 schedule of limits on hospital per diem inpatient general routine operating costs has been declared invalid with regard to the wage index for cost reporting periods beginning on or before July 1, 1981 and ending with cost reporting periods beginning on or before September 30, 1982. The District Court held that the decision to exclude Federal government hospital wage data from the computation of the wage index used in the 1981 Medicare hospital cost limits, without providing prior notice and an opportunity for comment, was in violation of the rulemaking requirements of the Administrative Procedure Act. The decision of the District Court does not apply to cost reporting periods beginning on or after October 1, 1982. The cost limits for periods beginning on or after October 1, 1982 are contained in the interim final notice with comment period published in the Federal Register on September 30, 1982 (47 FR 43296).

Centers for Medicare and Medicaid Services, U.S.↗
PubMed2000

Randomized trials of dichlorphenamide in the periodic paralyses. Working Group on Periodic Paralysis.

Although the carbonic anhydrase inhibitors have been used in the treatment of the primary periodic paralyses (PPs), their efficacy has not been demonstrated in double-blind, placebo-controlled trials. Therefore, we tested the efficacy of dichlorphenamide (DCP; Daranide), a potent carbonic anhydrase inhibitor, in the treatment of episodic weakness in the primary PPs. We performed two multicenter, randomized, double-blind, placebo-controlled crossover trials, one involving 42 subjects with hypokalemic periodic paralysis (HypoPP) and the other involving 31 subjects with potassium-sensitive periodic paralysis (PSPP). In each trial, two 8-week treatment periods were separated by an active washout period of at least 9 weeks. The primary outcome variable in the HypoPP trial was the occurrence of an intolerable increase in attack severity or frequency (end point). The primary outcome variable in the PSPP trial was the number of attacks per week. In the HypoPP trial, there were 13 subjects who exhibited a preference (in terms of the end point) for either DCP or placebo, and 11 of these preferred DCP. In the PSPP trial, DCP significantly reduced attack rates relative to placebo. DCP also significantly reduced attack rates relative to placebo in the HypoPP subjects. We conclude that DCP is effective in the prevention of episodic weakness in both HypoPP and PSPP.

Adolescent↗
PubMed1991

Influence of diethylcarbamazine on the patent period of infection in periodic Brugia malayi.

The patent period of infection which reflects the fecundic life span of the adult female worm was estimated for periodic B. malayi in south India by using immigration death model. Longitudinal data on natural loss of infection or that due to different degrees of DEC pressure in a cohort population of microfilaria carriers after a three years period, were used for the estimations. The patent period of infection was estimated to be 3.45 yr under natural conditions (without DEC therapy), which was reduced to 1.67 yr following one full course of selective therapy (6 mg/kg body wt/day for 12 days). When selective therapy was supplemented with four rounds of biannual single-dose mass DEC therapy (6 mg/kg body wt) the patent period was further reduced to 1.34 yr. The proportion loss of infection was relatively higher in microfilaria carriers who discontinued DEC selective therapy, when compared to natural loss. The percentage reduction in the mean microfilaria count was observed to decrease with increasing DEC pressure. Neither sex nor the age of the host was found to influence the fecundic life span or the survival of female adult worm.

Adolescent↗