Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

High power single-mode delivery of mid-infrared sources through chalcogenide fiber

Mechanically robust and low loss single-mode arsenic sulfide fibers are used to deliver high power mid-infrared sources. Anti-reflection coatings were deposited on the fiber facets, enabling 90% transmission through 20 cm length fibers. 10.3 W was transmitted through an anti-reflection coated fiber at 2053 nm, and uncoated fibers sustained 12 MW/cm² intensities on the facet without failure. A Cr:ZnSe laser transmitted >1 W at 2520 nm, and a Fe:ZnSe laser transmitted 0.5 W at 4102 nm. These results indicate that by improving the anti-reflection coatings and using a high beam quality mid-infrared source, chalcogenide fibers can reliably deliver ≥10 W in a single mode, potentially out to 6.5 µm.

Diffractive optical elements utilized for efficiency enhancement of photovoltaic modules

Common solar cells used in photovoltaic modules feature metallic contacts which partially block the sunlight from reaching the semiconductor layer and reduce the overall efficiency of the modules. Diffractive optical elements were generated in the bulk glass of a photovoltaic module by ultrafast laser irradiation to direct light away from the contacts. Calculations of the planar electromagnetic wave diffraction and propagation were performed using the rigorous coupled wave analysis technique providing quantitative estimations for the potential efficiency enhancement of photovoltaic modules.

A general method for quantitative measurement of molecular mass distribution by mass spectrometry

A method is presented to test whether the conversion of the mass spectrum of a polydisperse analyte to its molecular mass distribution is quantitative. Mixtures of samples with different average molecular masses, coupled with a Taylor's expansion mathematical formalism, were used to ascertain the reliability of molecular mass distributions derived from mass spectra. Additionally, the method describes how the molecular mass distributions may be corrected if the degree of mass bias is within certain defined limits. This method was demonstrated on polydisperse samples of C(60) fullerenes functionalized with ethylpyrrolidine groups measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; however, it is applicable to any polydisperse analyte and mass spectrometric method as long as spectrum resolution allows individual oligomers to be identified. Mass spectra of the derivatized fullerenes taken in positive ion mode were shown to give an accurate measurement of the molecular mass distribution while those taken in negative ion mode were not. Differences in the mechanisms for ion formation are used to explain the discrepancy. Official contribution of the National Institute of Standards and Technology; not subject to copyright in the United States of America.

Progesterone inhibits insulin-like growth factor binding protein-1 (IGFBP-1) production by explants of the Fallopian tube

The Fallopian tube provides the environment for early embryo growth, a process which is influenced by insulin-like growth factors (IGFs) in the tubal fluid. Whether the bioavailability of tubal IGFs is modulated by locally produced IGF-binding protein (IGFBP-1) is not clear. An explant culture system from human Fallopian tube mucosa was, therefore, developed enabling the potential for IGFBP-1 production by this tissue to be examined directly. Initial characterization of the system established that the explants maintained responsiveness to steroids. Thus, oviduct-specific glycoprotein production, a major product of the oviduct in vivo, continued to be made via an estrogen-sensitive pathway in the culture. The presence of mRNA for IGFBP-1 was established within the explants by the use of quantitative RT-PCR and IGFBP-1 protein was measured by enzyme-linked immunosorbent assay. Although insulin and estradiol had no consistent effect on IGFBP-1, addition of progesterone had a significant inhibitory effect on IGFBP-1 production, both at the mRNA and protein levels. A dose-range of progesterone revealed an incremental inhibitory effect of progesterone on IGFBP-1 output (maximal effect, 25-50 nmol/l), consistent with physiological inhibition of this process during the luteal phase. We suggest that progesterone might, therefore, play a role in controlling the bioavailability of IGFs to the embryo during early development within the Fallopian tube.

Luteinized human granulosa cells are associated with endogenous basement membrane-like components in culture

Human granulosa cells (GC), prepared from follicular aspirates using a non-enzymic method, were maintained in culture on chamber slides in a defined medium without additional attachment factors or extracellular matrix (ECM). In this system, GC clustered to a limited extent and attached only loosely to the substratum necessitating medium replacement through repeated partial changes to avoid cell loss. Using this new culture system, cell size and progesterone production per cell increased, consistent with continuing luteinization. These processes were associated with maintenance and deposition of endogenous ECM components. Thus, pericellular heparan sulphate proteoglycan (HSPG) was clearly visible by immunocytochemistry around the luteinized GC after culture. Also progressive accumulation of laminin (particularly alpha(2)-, beta(1)- and gamma(1)-subunits) during culture was shown by Western blotting of GC extracts. Small patches of collagen IV, shown to be already present between freshly prepared GC, were maintained in culture. A clear effect of gonadotrophin on the maintenance of progesterone production in culture was paralleled by an apparent increased pericellular deposition of HSPG. To conclude, luteinization and maintenance of the GC-derived layer of the corpus luteum is likely to involve deposition and conservation of pericellular ECM components.

Rearrangement of extracellular matrix during cluster formation by human luteinising granulosa cells in culture

Human ovarian granulosa cells were cultured on a basement membrane preparation (Matrigel) to investigate the role of extracellular matrix components in granulosa cell cluster formation. Time-lapse videomicroscopy of these cultures revealed a rapid aggregation of cells which was initiated during the first 2-4 h of culture so that by 8 h most of the granulosa cells were incorporated into clusters. Further amalgamation then occurred with the transfer of cells along 'bridges' between combining clusters. The clustering process, which was complete by about 24 h, was accompanied by reorganisation of matrix which was visualised by immunolabelling of laminin. Clustering cells appeared to gather matrix which became distributed around the clusters. Confocal microscopy showed matrix to be present over the surface of each cluster as well as around the base apparently anchoring the aggregate to the culture surface. Results suggest the potential for active rearrangement of matrix by granulosa-derived cells during corpus luteum development.

Morphology and functional characteristics of human ovarian microvascular endothelium

Corpus luteum formation is characterized by a period of extensive vascularization, as capillaries in the thecal layer of the collapsed follicle following ovulation invade the previously avascular granulosa layer. In order to study these processes in vitro we have developed an endothelial cell preparation from the specific microvasculature of the ovarian follicle. Follicular aspirates, obtained at oocyte collection for in-vitro fertilization (IVF), were filtered to obtain fragments of follicle wall. These were set in Matrigel and then cultured allowing the growth of capillary-like structures through the matrix. Upon emergence from the Matrigel the growing cells formed monolayers with the characteristic cobble-stone morphology of endothelial cells. Immunocytochemistry demonstrated the presence of a range of endothelial-specific markers including von Willebrand factor (vWF), Ulex europeus agglutinin (UEA)-1, CD31 and E-selectin, as well as VCAM-1, which is normally associated with stimulated endothelial cells. RT-PCR analysis showed the expression of two receptors for vascular endothelial growth factor (flt-1 and KDR), and the endothelial nitric oxide synthase, adding further evidence of their identity as human ovarian microvascular endothelial cells (HOMEC). Thus, the novel preparative procedure described now allows the generation of HOMEC cultures from readily available material resulting from IVF procedures.

Application of X-ray micrography and imaging to study the effect of gentamicin on Pseudomonas aeruginosa

Aminoglycosides disrupt the outer membrane of Pseudomonas aeruginosa to facilitate access to their intracellular target. High-resolution X-ray micrography of live specimens is a relatively new technique. We used laser (nanosecond) plasma to image live cells of P. aeruginosa ATCC 27853. After exposure to 25 mg/L gentamicin for 15 min. we observed perturbation of the cell surface, membrane blebbings (370 nm and 273 nm diameter) away from the cell, formation of distinct channels (241 nm long) resulting from indentation and induction of cell elongation from 3-3.6 microm (control) to 4.6-5.26 microm (gentamicin-treated cells). These data illustrate the potential of high-resolution X-ray micrography for studying effects of drugs on live microbiological specimens.

Comparison of computed tomography and ultrasonographic imaging in the assessment of blunt abdominal trauma in children

BACKGROUND

Computed tomography (CT) has become established in the assessment of paediatric blunt abdominal trauma. However, advances in diagnostic imaging necessitate reassessment of the role of available diagnostic modalities.

METHODS

Experience at a paediatric teaching hospital over a 5-year period was reviewed, with direct comparison of CT against ultrasonographic imaging in 26 children presenting with acute blunt abdominal trauma.

RESULTS

Intra-abdominal injury was diagnosed by CT in 23 of 24 patients compared with 21 on ultrasonography, although ultrasonography identified organ-specific injury in only 12 of 24 patients. CT was superior in the assessment of the multiply injured child, and identified spinal and pelvic injuries in three patients. CT augmented plain chest radiography in ten patients with associated thoracic injuries.

CONCLUSION

CT is the imaging modality of choice in children with severe abdominal trauma but ultrasonography is a reasonable technique to arouse diagnostic suspicion in less severe injuries or where CT is unavailable or delayed.

Gonadotrophin regulation of production of tissue inhibitor of metalloproteinases-1 by luteinized human granulosa cells: a potential mechanism for luteal rescue

Human granulosa cells were maintained in culture with extracellular matrix in the presence or absence of human chorionic gonadotrophin (HCG) using a defined culture medium. Such cultures are maintained by gonadotrophin in a manner suggesting that features of 'luteal rescue' may be occurring in vitro. Western analysis of culture medium demonstrated that the granulosa cells produced tissue inhibitor of metalloproteinases (TIMP)-1 but not TIMP-2. The presence of TIMP-1 in cultured cells was also detected immunocytochemically. Immunoassay of TIMP-1 output revealed that HCG exposure for 7 days caused a 2-fold increase in TIMP-1 production versus control reaching maximum at approximately 1 ng HCG/ml. The sensitivity of this response to HCG was similar to that observed for stimulation of progesterone production. Delayed addition of HCG, from day 4 of culture, elicited increases in TIMP-1 which were evident within 24 hours, and were not explained by changes in cell replication or survival. Removal of HCG from cultures previously luteinized with HCG for 6 days resulted in a fall in TIMP-1 production. Thus TIMP-1 production by luteinized granulosa cells in culture is gonadotrophin dependent. We speculate that prolonged cellular function associated with 'luteal rescue' may result from increased extracellular matrix stability mediated by up-regulation of TIMP-1 production.

X-ray micrography and imaging of Escherichia coli cell shape using laser plasma pulsed point x-ray sources

High-resolution x-ray microscopy is a relatively new technique and is performed mostly at a few large synchrotron x-ray sources that use exposure times of seconds. We utilized a bench-top source of single-shot laser (ns) plasma to generate x-rays similar to synchrotron facilities. A 5 microlitres suspension of Escherichia coli ATCC 25922 in 0.9% phosphate buffered saline was placed on polymethylmethyacrylate coated photoresist, covered with a thin (100 nm) SiN window and positioned in a vacuum chamber close to the x-ray source. The emission spectrum was tuned for optimal absorption by carbon-rich material. Atomic force microscope scans provided a surface and topographical image of differential x-ray absorption corresponding to specimen properties. By using this technique we observed a distinct layer around whole cells, possibly representing the Gram-negative envelope, darker stained areas inside the cell corresponding to chromosomal DNA as seen by thin section electron microscopy, and dent(s) midway through one cell, and 1/3- and 2/3-lengths in another cell, possibly representing one or more division septa. This quick and high resolution with depth-of-field microscopy technique is unmatched to image live hydrated ultrastructure, and has much potential for application in the study of fragile biological specimens.

Prenatal care and infant lead exposure

OBJECTIVE

The objective of the study was to determine the relation between prenatal care of mothers and blood lead concentrations in their offspring in the first year of life.

METHODS

A retrospective survey was conducted of 200 predominantly black infants between the ages of 6 and 22 months (mean age, 13.4 months). The infants had been screened for the first time since birth at the Charleston County (South Carolina) Health Department. They resided in a neighborhood with the highest prevalence of lead poisoning in Charleston. Prenatal care use data were obtained after matching birth records with lead-screening records.

RESULTS

Seventy-three infants (37%) had blood lead levels 0.48 micromol/L (> or = 10 microg/dl) or higher. Adequacy of prenatal care, defined by the Modified Kessner Index, showed 11% with intensive care (26% of these with high lead levels), 39% with adequate care (35% high blood lead levels), 35% with intermediate care (40% with high blood lead levels), 13% with inadequate care (42% with high blood lead levels), and 2% with no prenatal care (25% with high blood lead levels). With the exception of the small group with no prenatal care (n = 4), the proportion of infants with a high blood lead level was inversely proportional to the level of care. The logistic regression model that best fit the data included age at screen for lead and birth weight. Low birth weight babies (<2500 gm) were more likely to have a high blood lead level at primary screen than babies who were heavier at birth (odds ratio, 2.60; p = 0.04), and the older the baby at screening, the greater the likelihood of a high blood lead level (odds ratio, 1.23; p = 0.01). There was a trend for black infants to have a high blood lead level more often than white infants (odds ratio, 3.05; p = 0.06).

CONCLUSIONS

Less than adequate use of prenatal care may reflect an increase in risk factors contributing to lead exposure in infancy. Low birth weight also was related to high blood lead levels. Further studies are required to differentiate among several hypotheses for this effect. Intrauterine lead exposure, which is known to reduce birth weight, may contribute to measured blood lead levels at first screen. Alternatively, low birth weight may increase lead absorption and retention in infancy or may increase risk of lead exposure.

Incidence and nature of bile duct injuries following laparoscopic cholecystectomy: an audit of 5913 cases. West of Scotland Laparoscopic Cholecystectomy Audit Group

The rapid introduction of laparoscopic cholecystectomy has been associated with an apparently increased incidence of bile duct injury which has provoked worldwide concern. The true incidence and mechanism of iatrogenic ductal injury during the development of this procedure remain unclear. To assess this, the introduction of laparoscopic cholecystectomy in the West of Scotland has been audited prospectively over a 5-year period. All cases of biliary ductal injury have been independently reviewed. Some 48 surgeons undertaking laparoscopic cholecystectomy in 19 hospitals submitted prospective data between September 1990 and September 1995. A total of 5913 laparoscopic cholecystectomies were attempted with 98.3 per cent completion of data collection. During this period 37 laparoscopic bile duct injuries occurred. The annual incidence peaked at 0.8 per cent and has fallen to 0.4 per cent in the final year of audit. Injuries occurred after a median personal experience of 51 (range 3-247) laparoscopic cholecystectomies in 22 surgeons. Major bile duct injuries occurred in 20 of 37 patients, giving an incidence of 0.3 per cent. Five mechanisms for laparoscopic ductal injury were identified, including tenting, confluence and diathermy injuries as well as the classical and variant classical types. Ductal injuries were discovered at operation in 18 patients with consequent repair giving a good clinical outcome in 17. Contributory factors (severe inflammation, aberrant anatomy and poor visualization) were present in only 13 of 37 cases. This audit suggests that, at least in the introductory period, laparoscopic cholecystectomy is associated with an overall bile duct injury rate higher than that reported previously after open cholecystectomy, although the incidence of major ductal injury is similar. The late downward trend in bile duct injury, however, suggests there may be a prolonged learning curve for this procedure. Improved understanding of the mechanism of injury may lead to yet further reductions in this complication.

X-ray focusing with lobster-eye optics: a comparison of theory with experiment

We report an experimental investigation and comparison with simulation of the x-ray focusing of a flat, square profile microchannel plate. We use x rays with an energy of ~1.5 keV from a laser-produced plasma. The images were recorded with x-ray film. We find the focal structure to be consistent with theoretical expectations. The angular resolution of the focus is 0.96 mrad, which is a major improvement over previous results. The measured peak intensity gain is 27 ± 4, which is ~33% of that for a perfect optic.

Suppression of matrix metalloproteinase production by hCG in cultures of human luteinized granulosa cells as a model for gonadotrophin-induced luteal rescue

Granulosa cells were isolated from follicular aspirates collected at ovum recovery for in vitro fertilization. Cells were cultured in a defined medium on artificial extracellular matrix (Matrigel) in the presence or absence of hCG as a model for corpus luteum function. Release of cells from this culture system is reduced by hCG and this effect may be mediated through an inhibition of extracellular matrix degradation. Using zymography and western blot analysis, we confirm the identity of matrix metalloproteinases-2 and -9 in culture media. Matrix metalloproteinase-9 was the predominant gelatinase in freshly prepared granulosa cells and in culture media, and also represented a major metalloproteinase component in homogenates of early and mid-luteal phase samples of corpora lutea. Quantitative analysis of matrix metalloproteinases in culture media, obtained throughout the 14 day culture period and expressed per microgram of DNA, showed that matrix metalloproteinase-2, undetectable on day 2, rose throughout the culture period and that this rise was significantly inhibited by hCG. In contrast, matrix metalloproteinase-9 was clearly detectable on day 2 and remained relatively constant throughout much of the culture (day 2 to day 12) in the presence of gonadotrophin. Significantly increased production of matrix metalloproteinase-9 (day 6 to day 12) was evident in the absence of hCG. Our results provide further evidence for the hypothesis that the rescue of the corpus luteum in early pregnancy involves the maintenance of cellular function through the stabilization of the extracellular matrix.

Effect of human chorionic gonadotrophin on the detachment of human granulosa cells from extracellular matrix layered onto glass or plastic

We have previously shown that human granulosa cells cultured on a thin layer of extracellular matrix (ECM) are lost from culture in the absence of gonadotrophin. We now examine the effect of plating ECM onto glass or plastic. Such a comparison revealed that loss of cells from control cultures was more rapid when ECM was on glass, whereas cultures maintained with human chorionic gonadotrophin (HCG) showed greater stability when ECM was on plastic. The dose range of HCG required for the effect on cell retention was similar to that required for stimulation of progesterone production. Electron microscopy of cells freshly released as clusters revealed that many cells appeared undamaged, and confocal microscopy of cells stained with propidium iodide showed an absence of fragmented nuclei. Taken together, this evidence suggests that apoptosis is not the cause of cell release. We conclude that cells are released from culture, not as a result of cell death, but via an active process suppressed by HCG.

Effect of gonadotrophin on cell and matrix retention and expression of metalloproteinases and their inhibitor in cultured human granulosa cells modelling corpus luteum function

Granulosa cells were prepared from follicular aspirates obtained at oocyte collection for in-vitro fertilization (IVF) and maintained in culture. Substantial loss of cells from the culture surface occurred in the absence of gonadotrophin when cells were maintained on a thin layer of extracellular matrix (ECM) using a defined, serum-free medium. This cell loss was clearly and significantly reduced in the presence of human chorionic gonadotrophin (HCG) by days 4-6 of culture, and occurred in conjunction with loss of ECM. Analysis of culture medium by zymography using gelatin as substrate demonstrated the presence of metalloproteinases (MMP), MMP-9 (gelatinase B) appearing as the predominant band. Measurement of overall gelatinase activity in culture media revealed a progressive fall in gelatinase expressed on a per cell basis in media from HCG-treated cultures and this was less marked in controls. This suppression of gelatinase activity was consistent with an observed increase in production of tissue inhibitor of metalloproteinase-1 (TIMP-1) by HCG-treated cells, which was significant by days 6-8 of culture. We speculate that stabilization of the ECM may be an important aspect of HCG action in the corpus luteum.

Direct imaging in a water layer of human chromosome fibres composed of nucleosomes and their higher-order structures by laser-plasma X-ray contact microscopy

X-ray contact microscopy with a 300-ps-duration laser-plasma X-ray source has been used to image hydrated human chromosomes. Clearly imaged are individual nucleosomes and their higher-order particles (superbeads), elementary chromatin fibrils. c. 30 nm in diameter and their higher-order fibres of various sizes up to c. 120 nm in diameter. The results demonstrate that X-ray microscopy is now capable of opening a new path of investigation into the detailed structures of hydrated chromosome fibres in their natural state.

Characterization of a Flat-Field Grazing-Incidence XUV Spectrometer

We describe a XUV spectrometer for the study of dense hot microplasmas at wavelengths between ≈50 and ≈300 Å. It uses a commercially fabricated grazing incidence flat-field reflection grating with 1200 grooves per millimeter. The spectral resolution was optimized by imaging the source on a narrow slit with the help of a curved grazing incidence mirror. The instrument was tested with a laser-produced plasma as a source. The limit of the resolving power due to imaging aberrations of the flat-field grating ranges from 1500 at 50 Å to 3600 at 200 Å and has been achieved with a 5-μm slit. We also measured and calculated the grating efficiencies for the first to fifth diffraction order as a function of wavelength.

Gain properties of LiSrA1F(6) :Cr(3+)

Small-signal gain properties of Cr(3+)-doped LiSrAlF(6) are measured for the first time to our knowledge. Maximum small-signal gain values of 0.17 cm(-1) are reported for pi-polarized light. For sigma polarization, the gain is significantly suppressed by excited-state absorption.

Scintigraphic studies on the corneal residence of a New Ophthalmic Delivery System (NODS): rate of clearance of a soluble marker in relation to duration of pharmacological action of pilocarpine

1. A gamma scintigraphic study has been carried out on the precorneal residence and pharmacodynamic action of a radiolabelled New Ophthalmic Delivery System (NODS) containing pilocarpine nitrate in 12 healthy volunteers. 2. The NODS was radiolabelled with the soluble marker technetium-99m labelled diethylenetriaminepentaacetic acid, to mark the release characteristics of soluble drugs contained within the matrix. 3. The relationship between the precorneal residence time of the marker and the duration of drug effect on intraocular pressure and pupil diameter was monitored. Results obtained following administration of the NODS were compared with those obtained after administration of a 25 microliters drop of a 2% w/v pilocarpine nitrate solution. Each formulation was administered to one eye only, the other eye acting as a control. 4. Dissolution of the radiolabel from the NODS in vivo showed considerable intersubject variation with half-times of dissolution ranging from 46 s to 833 s (mean +/- s.d. -280 +/- 217 s), the mean (+/- s.d.) half-time of clearance of the radiolabel from the NODS and corneal region of interest was 406 +/- 214 s whereas the radiolabelled solution had a mean (+/- s.d.) ocular surface residence time of 2.9 +/- 1.5 s. 5. Pupil diameter and intraocular pressure were measured for 5 h post-administration of the NODS and the solution. After both treatments pupil diameter was significantly constricted in the test eye when compared with the control eye (P less than 0.001; Student's paired t-test). Pupil diameter was constricted by 52% after administration of the NODS and by 35% after administration of the solution.(ABSTRACT TRUNCATED AT 250 WORDS)

Cultured human granulosa cells as a model for corpus luteum function: relative roles of gonadotrophin and low density lipoprotein studied under defined culture conditions

In primates, corpus luteum development involves both gonadotrophin stimulation and exposure to low density lipoprotein (LDL) delivered through vascularization of the granulosa cell-derived layer. These regulatory influences were modelled in vitro using granulosa cells obtained during in-vitro fertilization (IVF) cycles controlled with gonadotrophin releasing hormone (GnRH) analogue, human menopausal gonadotrophin (HMG) and human chorionic gonadotrophin (HCG). Granulosa cells were cultured in defined medium on extracellular matrix. Without gonadotrophin or LDL in the medium, progesterone production declined progressively. With LDL alone, there was a short-lived elevation of progesterone output which subsequently declined. Culture with HCG alone resulted in a relatively unchanged rate of steroid production over 5 days despite morphological development. This contrasted with a marked and sustained increase in progesterone output over the same time when granulosa cells were cultured with combined HCG/LDL. Cultures were challenged with combined HCG/LDL on day 5. Where initial incubation included HCG, the challenge resulted in a recovery of progesterone output to values comparable to those of granulosa cells exposed to continuous HCG/LDL. Initial incubation without gonadotrophin led to a reduced response. Results suggest that LDL delivery to granulosa cells of the early corpus luteum causes a short-lived period of progesterone production. Sustained luteinization of granulosa cells and maintenance of gonadotrophin responsiveness requires continued exposure to gonadotrophin in the luteal phase.

Preincubation of human granulosa cells with gonadotrophin prevents the cloprostenol-induced inhibition of progesterone production

Human granulosa cells, from women undergoing ovum collection for in-vitro fertilization (IVF), will luteinize in vitro and provide a model for investigating the antigonadotrophic action of a prostaglandin F2 alpha (PGF2 alpha) analogue, cloprostenol, on granulosa-derived luteal cells. The granulosa cells were cultured in a defined medium and exposed to treatments during a preincubation period of 0 to 3 days and a final incubation with low density lipoprotein (LDL) from days 3 to 4. In the absence of human chorionic gonadotrophin (HCG), progesterone production was low, whereas exposure to HCG in the final incubation resulted in a 10-fold increase in progesterone concentrations. The inclusion of cloprostenol with HCG in the final incubation significantly (P less than 0.05) inhibited HCG-stimulated progesterone production. Exposure to HCG during the preincubation prevented the antigonadotrophic action of cloprostenol in the final incubation. The antigonadotrophic action of cloprostenol was retained when the granulosa cells were exposed to cloprostenol during the preincubation. Omission of LDL from the final incubation lowered the production of progesterone but the pattern of responses to HCG and cloprostenol were similar. Prevention of the antigonadotrophic action of cloprostenol after exposure to HCG may be a mechanism through which chorionic gonadotrophin can prevent regression of the corpus luteum in early pregnancy. Cloprostenol does not appear to inhibit LDL-stimulated steroidogenesis in human granulosa cells.

Size distribution of luteal cells from pregnant and non-pregnant marmoset monkeys and a comparison of the morphology of marmoset luteal cells with those from the human corpus luteum

The size distribution of marmoset luteal cells was determined on Days 6, 14 and 20 after ovulation in non-pregnant cycles and in early pregnancy. Image analysis was used to estimate the cell diameter of dispersed cells prepared from the marmoset corpus luteum (CL). Steroidogenic cells showed a size distribution consistent with one population of cells. There was a significant increase in mean cell diameter (P less than 0.05) from Day 6 to Day 14 in pregnant and non-pregnant animals with no further increase on Day 20. Micrographs of marmoset luteal tissue showed cells of greater than 10 micron containing the organelles typical of steroid-producing cells, and smaller non-steroidogenic cells surrounding the steroid-producing cells. On the basis of microscopy, there were no areas within the CL where cell composition was noticeably different. In contrast, micrographs of human luteal tissue showed two types of steroidogenic cell; most cells were similar to those in the marmoset CL but a smaller population of smaller cells could be distinguished around the periphery and along vascular septa. It is likely that these smaller and larger types of steroidogenic cells are of theca and granulosa cell origin respectively, the two cell populations differing in the degree of electron density and amount of rough endoplasmic reticulum. A distinguishing feature between marmoset and human luteal cells was the shape of the mitochondrian which were considerably rounder in marmoset luteal cells. The origin of steroidogenic cells in the marmoset CL is unclear, although in marmosets and man the luteal cell types display morphological characteristics distinct from the large and small luteal cells described for CL of the domestic ungulates.

Changing responsiveness of luteal cells of the marmoset monkey (Callithrix jacchus) to luteotrophic and luteolytic agents during normal and conception cycles

Dispersed marmoset luteal cells were incubated for 2 h and progesterone production measured after exposure to hCG, cloprostenol, dibutyryl cAMP, PGF-2 alpha, PGF-2, adrenaline or melatonin. The cells were studied on Days 6, 14 and 20 after ovulation in conception and non-conception cycles. Luteal cells from Day 14 non-pregnant marmosets were compared with human luteal cells taken in the mid-luteal phase. All the treatments stimulated progesterone production including cloprostenol, which is luteolytic when administered to the marmoset in vivo, but the degree of response varied with the stage of the cycle or pregnancy and between marmoset and human luteal cells. In the marmoset, overall analysis of the effect of the treatments showed that, on Day 6 after ovulation, there was no significant effect of any of the treatments in cells from pregnant or non-pregnant animals. In contrast, luteal cells from non-pregnant animals on Day 14 showed a significant response to the treatments (F (8,41) = 2.79, P less than 0.0145) whereas cells from pregnant Day-14 animals were responsive; in cells from pregnant animals, the control production of progesterone was high and already equivalent to the levels stimulated by the treatments. By Day 20, cells from pregnant animals produced lower control concentrations of progesterone than did those on Day 14 and there was a significant overall effect of the treatments (F (8,33) = 3.78, P less than 0.003). These results show that the marmoset CL gains responsiveness to treatment between Days 6 and 14 after ovulation in the non-pregnant cycle. In pregnancy, on Day 14, 2 days after attachment of the embryo, the high control concentrations of progesterone and absence of response to treatment suggest that an embryo message may have affected the CL, providing an endogenous stimulus.

Augmentation by epidermal growth factor of basal and stimulated progesterone production by human luteinized granulosa cells

Human granulosa cells were prepared from follicular aspirates obtained during oocyte collection for in vitro fertilization. Following several days in culture, cells were washed and then progesterone output was measured in 2-h incubations. After culture for 3 days, incubated cells responded well to human chorionic gonadotrophin (hCG) and prostaglandin (PG) E2 with similar levels of maximum response. Exposure of cultured cells to epidermal growth factor (EGF) for 2 days (days 3-5) led to substantial increases both in basal production and in responses to hCG and PGE2 during subsequent incubations. These effects of EGF were not accompanied by measurable increases in DNA levels in cultures over this time. Results may point to a possible paracrine role for EGF-like factors modulating the activity of cells forming the early corpus luteum.

Grazing incidence technique to obtain spatially resolved spectra from laser heated plasmas

An experimental method is described in which a grazing incidence spectrograph is used to obtain spatially resolved spectra of laser heated plasmas in the 6-370-A region. In the experiment, small target spheres were irradiated by tightly focused laser beams. A tilted grazing incidence elliptical mirror placed 1.3 m from the target focuses the plasma radiation on the spectrograph slit at a distance of 0.7 m producing a useful degree of spatial resolution in the recorded spectral lines. The spectrum from a copper target is presented together with an x-ray pinhole camera image of the plasma.

Regeneration of submandibular gland autografts in sympathectomized rats

This morphologic study compares the regenerative response in submandibular gland (SMG) autografts placed in the tongues of previously sympathectomized rats to autografts placed in tongues of sham-sympathectomized rats. We hypothesized that sympathectomy would alter the process of cellular proliferation and inhibit cytodifferentiation in regenerating SMG autografts. Either 1 week, or 8 to 11 weeks following the SMG autografting procedure, the rats were sacrificed and their tongues were removed and sectioned in a cryostat. Frozen tissue sections containing the SMG autografts were either reacted for cholinesterase activity, treated with a glyoxylic acid mixture to induce histofluorescence, or stained for histologic examination. In addition, 3H-thymidine labeled and unlabeled cells were counted in autoradiographs of 1-week autografts, and these counts were used to calculate labeling indices. The 1-week SMG autografts from both the sympathectomized and the sham-sympathectomized rats were similar in histologic appearance, and neither group of autografts contained cholinesterase-positive or monoaminergic nerve fibers. The 8- to 11-week autografts from sympathectomized and sham-sympathectomized rats contained cholinesterase-positive fibers, but monoaminergic fibers were present in the autografts only from the sham-operated rats. Acinar cells were observed in one-third of the 8- to 11-week autografts of both the sympathectomized and sham-sympathectomized rats. This finding suggests that sympathectomy did not prelude cytodifferentiation in the autografts. The autoradiographic data revealed no statistically significant difference between the mean labeling indices of the 1-week autografts from the sympathectomized and sham-sympathectomized rats, which suggests that sympathectomy also did not alter the level of cellular proliferation in the autografts.

Lack of direct inhibitory action of oxytocin on progesterone production by dispersed cells from human corpus luteum

Suspensions of luteal cells were prepared from samples of human corpora lutea obtained during the luteal phase of menstrual cycles. Addition of oxytocin (1 mumol/l) to the various cell preparations had no effect on either basal production of progesterone or on steroidogenic responses to a range of concentrations of gonadotrophin.