FOLLICLE KINETICS IN THE OVARY OF THE CYCLIC MOUSE

1970 ◽  
Vol 64 (2) ◽  
pp. 304-323 ◽  
Author(s):  
Torben Pedersen
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Tritiated Thymidine ◽  
Ovarian Follicle ◽  
Medium Size ◽  
Time Interval ◽  
Pulse Labelling ◽  
Full Development ◽  
Time Required ◽  
Doubling Times

ABSTRACT The variations in size, numbers and growth rates of mouse ovarian follicles were investigated at different stages of the oestrous cycle. Autoradiographs were prepared of sections of ovaries after pulse-labelling with tritiated thymidine. By determining the growth rate of the granulosa cells expressed as their doubling times, it was possible to estimate the exact growth rates of whole follicles. The number of follicles which began developing during a particular time interval was also determined. The results show that the number of large follicles fluctuates with the cycle, and that the size of the largest follicles increases during the cycle. Follicles of medium size grow faster at oestrus that at any other time. This is in contrast to the large follicles, in which only minor variations in growth rate were noted. It was moreover shown, that more follicles begin to grow at oestrus than at other periods during the cycle. It was concluded, that the reduction in the number of small follicles with age is mainly due to follicle development rather than to the degeneration of small follicles. The time required for the full development of an ovarian follicle is 19 days.

Centennial-scale climate variability inferred from Las Gloces cave in Central Pyrenees: evidences of rapid changes during last glacial cycle

2021 ◽  
Author(s):  
Ana Moreno ◽  
Miguel Bartolomé ◽  
Carlos Sancho ◽  
Eneko Iriarte ◽  
Ánchel Belmonte ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Time Interval ◽  
Glacial Period ◽  
Last Deglaciation ◽  
Glacial Cycle ◽  
Last Glacial Period ◽  
The Holocene ◽  
Last Glacial ◽  
Central Pyrenees

<p>Paleoclimate records from the Pyrenees covering last glacial period are scarce since many lakes were covered by the glaciers, glacier deposits just provide discontinuous information and in very few caves we can find speleothem growth during that cold and generally dry time period. Las Gloces cave, located close to Ordesa and Monte Perdido National Park (Central Pyrenees, Iberian Peninsula) at 1240 m a.s.l., is one the few examples to study that time interval. Thus, for the first time, we present a speleothem in the Pyrenees that was growing during the Maximum Ice Extent in the last glacial period in a cave located just 3 km away from the glacier. Two speleothems from las Gloces were sampled, one covering the Holocene and last deglaciation (last 16.6 ka) and the other one growing from MIS4 (67.8 ka) to Mid-Holocene (4.7 ka), with two hiatuses at 50-47 ky and 30-21 ka coinciding with cold/dry periods. Both stalagmites were dated and analyzed for stable i sotopes and trace elements.</p><p> </p><p>During MIS4, the lowest growth-rates correspond with Heinrich Stadial (HS) 6 while there is an increase in growth rate during MIS3 onset, reaching the maximum at Greenland Interstadial (GI)-14. After this, and corresponding with HS5, the growing stopped and it will reactivate again during GI-12, but with low growth rates. A new interruption took place 30 ka ago, with a second hiatus (30-21 ka), corresponding with an important retreat of Central Pyrenees glaciers and maximum regional aridity. During last glacial period, δ<sup>13</sup>C and δ<sup>18</sup>O records vary with rather small amplitude of change (4 ‰ and only 1‰, respectively) and showing low correlation between them indicating they were likely affected by different influences. At 21 ka BP, there is a new speleothem growth that will be characterized by the heaviest δ<sup>13</sup>C and δ<sup>18</sup>O values in the record (0‰ and -7‰, respectively) that occurred during the global LGM period.</p><p> </p><p>Changes in the growth rate in those stalagmites could be related to precipitation oscillations during GS-GI cycles while the variation in δ<sup>13</sup>C could respond with changes in the temperature and rainfall on a glacial landscape with reduced vegetation cover. Differences in mean values of δ<sup>13</sup>C between MIS3 (-5‰) and Holocene (-9‰) represent a forest revegetation over the cave related with the climatic amelioration experienced during last deglaciation due to the increase in temperature and humidity. Drivers on δ<sup>18</sup>O change during MIS 3 are multiple and more complex but they may correspond to changes in amount of rainfall, temperature or moisture source. The drastic change in d<sup>18</sup>O during last deglaciation (from -10‰ at HS1 to -7 ‰ at the onset of the Holocene) could be additionally related to the well-known isotopic change of sea surface water due to the massive entrance of freshwater into the north Atlantic region.</p>

The Natural History of Incidental Meningiomas

Neurosurgery ◽  
2003 ◽  
Vol 53 (1) ◽  
pp. 62-71 ◽  
Author(s):  
Makoto Nakamura ◽  
Florian Roser ◽  
Julia Michel ◽  
Cornelius Jacobs ◽  
Madjid Samii
Keyword(s):  
Growth Rate ◽  
Natural History ◽  
Tumor Growth ◽  
Growth Rates ◽  
Tumor Size ◽  
Annual Growth ◽  
Tumor Doubling Time ◽  
History Of ◽  
Doubling Times ◽  
Initial Tumor Size

Abstract OBJECTIVE Little information about the natural history of incidental meningiomas exists in the literature. The aim of this study was to determine the natural history of asymptomatic meningiomas by comparing different methods of growth rate calculation to establish a strategy for dealing with these tumors. METHODS In 47 asymptomatic patients, hospital charts, follow-up records, and imaging studies were reviewed. Of these patients, 6 underwent surgery. Tumor growth rates were determined by calculating the absolute and relative growth rates and the tumor volume doubling times. RESULTS In 41 patients with conservative management, the average tumor size was 9 cm3, and the majority (66%) of growth rates were less than 1 cm3/yr. The absolute growth rate ranged from 0.03 to 2.62 cm3/yr (mean, 0.796 cm3/yr). Relative annual growth rates ranged from 0.48 to 72.8% (mean, 14.6%). The tumor doubling time ranged from 1.27 to 143.5 years (mean, 21.6 yr). A moderate correlation between the age and growth rates was found. In young patients, annual growth rates tended to be higher and tumor doubling times shorter. There was no clear correlation between the initial tumor size and tumor doubling time. The mean annual growth rate of meningiomas with calcification was lower than in tumors without calcification. Also, tumors with hypointense or isointense T2 signals on magnetic resonance imaging had a lower growth rate. In the group of six patients with surgical excision, tumor growth rates were higher and tumor doubling times shorter than in the nonsurgical group. CONCLUSION The majority of incidental meningiomas show minimal growth; thus, they may be observed without surgical intervention unless specific symptoms appear. Tumor growth is associated with patient age. The initial tumor size is not considered a predictive factor for tumor growth. Radiological features, such as calcification or T2 signal intensity, may provide useful information to predict the growth potential of meningiomas.

FOLLICLE GROWTH IN THE IMMATURE RAT OVARY

1978 ◽  
Vol 88 (2) ◽  
pp. 375-382 ◽  
Author(s):  
A. J. Hage ◽  
A. C. Groen-Klevant ◽  
R. Welschen
Keyword(s):  
Granulosa Cells ◽  
Tritiated Thymidine ◽  
Pulse Labelling ◽  
Follicle Growth ◽  
Immature Rat ◽  
Stage Of Development ◽  
Different Ages ◽  
Old Rats ◽  
Rat Ovary ◽  
Doubling Times

ABSTRACT In ovaries of immature rats the following parameters were estimated from autoradiographs prepared after pulse labelling with tritiated thymidine: 1) The time it takes follicles to grow from one stage of development to another. This could be derived from the total number of granulosa cells in these stages and from their doubling times. The doubling time of granulosa cells was determined from their labelling index and the duration of their DNA-synthesis phase. 2) The number of follicles present in the ovary at different ages. 3) The number of follicles, which start on their development at different ages. It was found, that more follicles start to grow in 8 and 16 days old rats (2.0/h) than in 28 days old ones (1.0/h). Moreover, the follicles grow somewhat faster earlier in life than later. The development from a follicle with one layer of granulosa cells to one with several layers and antrum formation takes about 15 days in the first half of the period of immaturity while it takes about 17 days as the animal approaches maturity.

scholarly journals Determination of In Situ Bacterial Growth Rates in Aquifers and Aquifer Sediments

2003 ◽  
Vol 69 (7) ◽  
pp. 3798-3808 ◽  
Author(s):  
Brian J. Mailloux ◽  
Mark E. Fuller
Keyword(s):  
Growth Rate ◽  
Fluorescence Intensity ◽  
Growth Rates ◽  
Direct Determination ◽  
Shallow Aquifer ◽  
Cell Counting ◽  
Field Scale ◽  
Doubling Times

ABSTRACT Laboratory and field-scale studies with stained cells were performed to monitor cell growth in groundwater systems. During cell division, the fluorescence intensity of the protein stain 5-(and 6-)-carboxyfluorescein diacetate succinimidyl ester (CFDA/SE) for each cell is halved, and the intensity can be tracked with a flow cytometer. Two strains of bacteria, Comamonas sp. strain DA001 and Acidovorax sp. strain OY-107, both isolated from a shallow aquifer, were utilized in this study. The change in the average generation or the average fluorescence intensity of the CFDA/SE-stained cells could be used to obtain estimates of doubling times. In microcosm experiments, the CFDA/SE-based doubling times were similar to the values calculated by total cell counting and were independent of cell concentration. Intact and repacked sediment core experiments with the same bacteria indicated that changes in groundwater chemistry were just as important as growth rates in determining planktonic cell concentrations. The growth rates within the sediment cores were similar to those calculated in microcosm experiments, and preferential transport of the daughter cells was not observed. The experiments indicated that the growth rates could be determined in systems with cell losses due to other phenomena, such as attachment to sediment or predation. Application of this growth rate estimation method to data from a field-scale bacterial transport experiment indicated that the doubling time was approximately 15 days, which is the first known direct determination of an in situ growth rate for bacteria in an aquifer.

FOLLICLE GROWTH IN THE IMMATURE MOUSE OVARY

1969 ◽  
Vol 62 (1) ◽  
pp. 117-132 ◽  
Author(s):  
Torben Pedersen
Keyword(s):  
Granulosa Cells ◽  
Tritiated Thymidine ◽  
List Type ◽  
Pulse Labelling ◽  
Follicle Growth ◽  
Mouse Ovary ◽  
Stage Of Development ◽  
Different Ages ◽  
Immature Mouse ◽  
Doubling Times

ABSTRACT The growth of follicles in the immature mouse ovary was investigated in autoradiographs prepared after pulse-labelling with tritiated thymidine. Three parameters, which determine follicle growth were estimated: The number of follicles present in the ovary at different ages. The time it takes follicles to grow from one stage of development to another. This was calculated from the total number of granulosa cells in these stages and from their doubling times. The doubling time of granulosa cells was determined from their labelling index and the duration of their DNA-synthesis phase. The number of follicles, which start on their development at different ages. It was found, that the follicle development is not constant in the period from birth to maturity, but varies considerably. More follicles start to grow in the young than in the older immature mouse. Moreover the follicles grow faster early in life than later. The development from a follicle with one layer of granulosa cells to one with several layers and antrum formation takes about 10 days in the first half of the immature period, while it takes about 16 days as the animal approaches maturity. It was furthermore shown, that about 850 follicles start to grow in the immature period.

scholarly journals Initiation and Velocity of Chromosome Replication in Escherichia coli B/r and K-12

1998 ◽  
Vol 180 (2) ◽  
pp. 265-273 ◽  
Author(s):  
Meeshel Bipatnath ◽  
Patrick P. Dennis ◽  
Hans Bremer
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Cell Mass ◽  
Chromosome Replication ◽  
Chromosomal Replication ◽  
Copy Numbers ◽  
Identical Manner ◽  
Time Required ◽  
K 12

ABSTRACT The macromolecular composition and a number of parameters affecting chromosome replication were examined over a range of exponential growth rates in two common Escherichia coli strains, B/r and K-12 AB1157. Based on improved measurements of DNA after treatment of exponential cultures with rifampin, the cell mass per chromosomal replication origin (initiation mass) and the time required to replicate the chromosome from origin to terminus (C period) were determined. For these two strains, the initiation mass approached values of 8 × 10−10 and 10 × 10−10 units of optical density (at 460 nm) of culture mass per oriC, respectively, at growth rates above 1 doubling/h (at 37°C). The amount of protein per oriC decreased with increasing growth rate for AB1157 and remained nearly constant for the B/r strain. The C period decreased for both strains in an essentially identical manner from about 70 min at 0.6 doublings/h to about 33 min at 3 doublings/h. From the initiation mass andC period, relative or absolute copy numbers for genes with known map locations can be accurately determined at different growth rates. At growth rates above 2 doublings/h, when chromosomes are highly branched, genes near the origin are about threefold more prevalent than genes near the terminus. At a growth rate of 0.6 doubling/h, this ratio is only about 1.7, which reflects the lower degree of chromosome branching.

Growth Rates of Intertidal Molluscs as Indicators of Effects of Unexpected Incidents of Pollution

1973 ◽  
Vol 30 (9) ◽  
pp. 1385-1388 ◽  
Author(s):  
Robert Black
Keyword(s):  
Growth Rate ◽  
Mytilus Edulis ◽  
Growth Rates ◽  
Littorina Littorea ◽  
Time Interval ◽  
Elemental Phosphorus ◽  
Phosphorus Pollution ◽  
Nonlethal Effects

Shells of living molluscs contain a record of previous growth rate if the time interval between check marks is known. The check marks in Mytilus edulis and Littorina littorea are probably annual marks. Growth rates of Mytilus in 1969, the year of significant elemental phosphorus pollution at Long Harbour, Newfoundland, were no different from those in preceding or succeeding years. No Littorina alive in 1969 occurred at Long Harbour, but they were abundant at other locations. This sort of analysis, used with caution because effects of pollutants may be confounded with effects of other variables, provides a method of examining nonlethal effects of unexpected polluting events.

Non-Gaussian behavior of the internet topological fluctuations

2014 ◽  
Vol 25 (05) ◽  
pp. 1440012 ◽  
Author(s):  
Qu Chen ◽  
Jiang-Hai Qian ◽  
Ding-Ding Han
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
The Internet ◽  
Time Interval ◽  
Scaling Relation ◽  
Power Law Decay ◽  
Exponential Decrease ◽  
Non Gaussian ◽  
Growth Rate Distribution ◽  
Topological Fluctuations

The traditional Gibrat's hypotheses were once used to model the topological fluctuations of Internet. Although it seems to reproduce the scaling relation of Internet's degree distribution, the detailed micro-dynamics have never been empirically validated. Here, we analyze the distribution of degree growth rates of the Internet for various time scales. We find that in contrast to the traditional Gibrat's assumptions, none of the degree growth rates are normally distributed, but behaves as an exponential decrease on its body and a power-law decay on its tail. Moreover, the observed growth rate distribution turns out independent of the initial degree when the time interval enlarges to a year. Our observations do not consist with the traditional Gibrat law model and suggest a more complex fluctuation mechanism underlying the evolution of Internet.

External Corrosion Growth-Rate From Soil Properties

2010 ◽  
Author(s):  
Khalid A. Farrag
Keyword(s):  
Growth Rate ◽  
Corrosion Rate ◽  
Soil Properties ◽  
Growth Rates ◽  
Soil Conditions ◽  
Soil Parameters ◽  
Time Interval ◽  
Soil Redox Potential ◽  
Corrosion Rates ◽  
External Corrosion

External corrosion growth rate is an essential parameter to establish the time interval between successive pipe integrity evaluations. Actual corrosion rates are difficult to measure or predict. NACE Standard RP0502 [1] recommends several methods including comparison with historical data, buried coupons, electrical resistance (ER), and Linear Polarization Resistance (LPR) measurements. This paper presents a testing program and procedure to validate the use of the LPR and ER methods to enhance the estimation of corrosion growth rates and improve the selection of reassessment intervals of gas transmission pipelines. Laboratory and field tests were performed using the LPR and ER technologies. The evaluation of soil parameters that affect localized corrosion included its type, moisture content, pH, resistivity, drainage characteristics, chloride and sulfite levels, and soil Redox potential. The results show that the LPR device provides instantaneous measurement of corrosion potential and it may be used to reflect the variations of corrosion rates with the changes of soil conditions, moisture, and temperature. However, LPR measurements are more efficient in saturated soils with uncertainty about its validity in partially and totally dry soils. Consequently, seasonal changes in soil conditions make it difficult to estimate total corrosion growth rate. On the other hand, the measurements using the ER method provided consistent estimates for long-term corrosion growth rates. Corrosion growth rates were also evaluated from a previous study by the National Institute of Standards (NIST) [2]. A procedure was developed to correlate soil properties to corrosion rates from the ER measurements and NIST data. The procedure was implemented in a computer program to provide an estimate of corrosion rate based on the soil input data and allows the operator to use the ER probes to improve the reliability of corrosion rate estimates.

Replication, differentiation, growth and the virulence ofTrypanosoma bruceiinfections

Parasitology ◽  
1995 ◽  
Vol 111 (3) ◽  
pp. 289-300 ◽  
Author(s):  
C. M. R. Turner ◽  
N. Aslam ◽  
C. Dye
Keyword(s):  
Growth Rate ◽  
Trypanosoma Brucei ◽  
Acute Phase ◽  
Growth Rates ◽  
Chronic Phase ◽  
Population Doubling ◽  
Phase Growth ◽  
Laboratory Procedure ◽  
Age Dependent ◽  
Doubling Times

SUMMARYThis study had 2 objectives: first, to investigate how the processes of slender form replication, of differentiation from dividing slender to non-dividing stumpy forms, and of stumpy mortality, combine to determine the initial (acute-phase) growth rate ofTrypanosoma bruceipopulations; second, to determine how acute-phase growth rates influence parasite densities during the subsequent, chronic phase of infection. During the acute phase, slender and stumpy populations both grew approximately exponentially, the latter more slowly than the former. Mathematical models showed how this difference in slender and stumpy growth rates can be explained in terms of heterogeneous replication and differentiation rates. Stumpy life-expectancy was determined for one stock and found to be age-dependent with a half-life of 48–72 h, much larger than observed population doubling times of 5–10 h. A comparison of cloned stocks showed that the highest parasite densities during the chronic phase were associated with the highest acute-phase growth rates of both the whole parasite population and of the subpopulation of slender forms. By contrast, high chronic-phase parasitaemias artificially produced following rapid syringe passage were associated with low acute-phase growth rates of slender forms. Syringe-passaging is a laboratory procedure which selects for virulent parasites, but these parasites behave differently from naturally virulent stocks.

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