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E Anderson

Publications and source records attributed to E Anderson.

At least 19 recordsLinked to original sources
PubMed1992

X-ray laser microscopy of rat sperm nuclei.

The development of high brightness and short pulse width (< 200 picoseconds) x-ray lasers now offers biologists the possibility of high-resolution imaging of specimens in an aqueous environment without the blurring effects associated with natural motions and chemical erosion. As a step toward developing the capabilities of this type of x-ray microscopy, a tantalum x-ray laser at 44.83 angstrom wavelength was used together with an x-ray zone plate lens to image both unlabeled and selectively gold-labeled dried rat sperm nuclei. The observed images show approximately 500 angstrom features, illustrate the importance of x-ray microscopy in determining chemical composition, and provide information about the uniformity of sperm chromatin organization and the extent of sperm chromatin hydration.

Animals↗
PubMed1992

Cystogenesis of the ovarian antral follicle of the rat: ultrastructural changes and hormonal profile following the administration of dehydroepiandrosterone.

Immature 27-day-old female Sprague-Dawley rats were administered daily subcutaneous injections of dehydroepiandrosterone (DHEA, 5 mg/100 g BW) to induce the formation of ovarian follicular cysts. Groups of rats were killed on days 0, 10, 15, 20, 25, and 30. Ovaries from each group of rats were processed for light and electron microscopy and for follicular or cystic fluid hormone analysis. Normal antral follicle fluid, PMSG-treated preovulatory follicular fluid, and cystic fluids were analyzed for progesterone (P), estrone (E1), estradiol (E2), testosterone (T), delta 4-androstenedione (delta 4-A), 5 alpha-dihydrotestosterone (DHT), luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin (PRL). DHEA induced anovulation, acyclicity, and the formation of follicular cysts. In certain antral follicles, there was a dramatic increase in the quantities of smooth endoplasmic reticulum (SER) in the granulosa cells and many mitochondria had tubular cristae. Further depletion of granulosa cell number was associated with intense blebbing of the cytoplasm into the follicle antrum. Formation of the ovarian follicular cyst was completed when the entire cyst was lined by a single layer of transformed granulosa cells in contact via adhering, gap, and tight junctions. These cells had little cytoplasm, mitochondria with lamellar cristae, vast basal and apical bands of microfilaments, and an extensive array of smooth-surfaced endocytotic invaginations on the basal plasma membrane. These endocytotic pits may subsequently form smooth-surfaced vesicles and thereby serve as one mechanism for moving fluid from the ovarian interstitium into the cyst. Theca interna cells were rarely observed in the peripheral regions of the cyst. Abundant smooth muscle cells were located beneath the basement membrane of the epithelial cells comprising the cyst wall. These acquired morphological and physiological features may ensure persistence of the ovarian cyst and thus potentiate a chronic pathological condition. In this study it was also shown that progesterone, estrone, and estradiol as well as androgen concentration increased in the follicle after PMSG treatment. With DHEA treatment, the follicular cystic fluid concentrations of these steroids progressively increased to extremely high levels concurrent with the development of the follicular cysts.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Oral contraceptive (OCP) use increases proliferation and decreases oestrogen receptor content of epithelial cells in the normal human breast.

The effect of ingestion of oral contraceptives (OCP) on cell proliferation and oestrogen (ER) and progesterone receptor (PR) expression of the epithelial cells of the normal human breast was compared with findings in controls not taking OCPs. Histologically normal breast tissue was removed during operation for fibroadenoma or reduction mammoplasty in 216 women whose mean age was 28.1 +/- 8.5 years (+/- SD range 14-53 years). During natural cycles the mean proportion of cells expressing ER was 3.94 +/- 3.71 (% mean +/- SD, range 0-20.8, n = 51), while of those expressing PR it was 12.1 +/- 7.1% (range 3.0-36.1, n = 47). There was a significant decline in ER during the menstrual cycle [p = 0.001 by multiple linear regression (MLR)], but there was no significant change in the proportion which expressed PR. The mean proportion of proliferating cells (LI) was 2.50 +/- 2.42 (range 0-11.5, n = 147). There was a significant increase of LI during the cycle (p = less than 0.001, MLR) and a significant inverse relationship between LI and ER (r = -0.29, p less than 0.01). Use of the OCP significantly reduced the number of cells which expressed ER and increased the LI earlier in the cycle. No effect of OCP use on the number of PR+ cells was detectable. We conclude that significant changes in the proportions of ER+ and proliferating cells occur during natural menstrual cycles. These changes are perturbed by ingestion of OCPs, so that there is greater suppression of ER and a longer period of high proliferation during the menstrual cycle. These results may explain the relationship between OCP use and the possible risk of breast cancer.

Adolescent↗
PubMed1991

Platelet-derived growth factor receptor alpha-subunit gene (Pdgfra) is deleted in the mouse patch (Ph) mutation.

Platelet-derived growth factor receptors are composed of two subunits (alpha and beta) that associate with one another to form three functionally active dimeric receptor species. The two subunits are encoded by separate loci in humans and other species. In this study, we used conventional interspecific backcross mapping and an analysis of a deletional mutation to establish close linkage between the alpha-subunit gene (Pdgfra) and the dominant spotting (W) locus on mouse chromosome 5. Further, by analyzing the restriction fragment length polymorphisms in interspecific F1 hybrids, we were able to demonstrate that the closely associated patch (Ph) locus carries a deletion in Pdgfra. This observation was confirmed by both DNA and RNA analysis of 10.5-day fetuses produced from crosses between Ph heterozygotes. Out of 16 fetuses analyzed, Pdgfra genomic sequences were absent and no mRNA for the receptor was detected in 6 fetuses that were developmentally abnormal (the presumptive Ph homozygotes). We also determined that the deletion associated with the Ph mutation does not extend into the coding sequences of the adjacent Kit gene, by analysis of the genomic DNA from both the interspecific F1 hybrids and the presumptive Ph homozygotes. The absence of Pdgfra genomic sequences and the lack of detectable message associated with the Ph mutation should make this mutant a valuable asset for understanding the role of the receptor alpha subunit during mammalian development.

Animals↗
PubMed1991

Heterogeneity in granulosa cells of developing rat follicles.

The present study was designed to characterize the granulosa cell subpopulations derived from rats in which ovarian growth was induced by diethylstilbestrol (DES) or in which growth and differentiation was induced by pregnant mare's serum gonadotropin (PMSG). In the DES model, immature rats were given two separate injections of 2 mg DES/rat s.c. on 25 and 26 days of age and were killed 24 hr after the second injection. In the PMSG model, rats on day 28 were given 8 IU of PMSG s.c. and were killed 54 hr later. Granulosa cells were isolated from the ovaries, separated on a continuous Percoll density gradient, and divided into 12 fractions. The cells in each fraction were cultured in the presence of androstenedione with or without 20 ng/ml of follicle-stimulating hormone (FSH) and estradiol and progesterone in the incubation medium were measured. In DES-treated rats, granulosa cells in fractions 4 and 5 and fractions 9 and 10 contained about 30-40% of total cell yield and showed high steroidogenic potential. Granulosa cells from fractions 6, 7, and 8, which represent 55-60% of total cell yield, produced relatively low amounts of steroids on a per-million-cell basis. FSH was required for the stimulation of steroidogenesis. In granulosa cells from the PMSG treated rats, aromatase activity appeared maximally induced and incubation with FSH in vitro did not bring about any further increase. However, in vitro incubation with FSH was required for progesterone production. Furthermore, the granulosa cells from the PMSG treated rats also showed much more active estradiol and progesterone synthesis in fractions 9-12 as compared with lower density fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Changes in ovarian morphology and serum hormones in the rat after treatment with dehydroepiandrosterone.

This investigation was designed to study ovarian and hormonal changes in the rat after treatment with dehydroeplandrosterone (DHEA). We identified a heterogeneous experimental group of animals with respect to ovarian histology: group I, corpora lutea (Cls) + cysts; group II, CLs + no cysts; group III, no CLs + cysts; group IV, no CLs + no cysts. Histological sections of these ovaries showed healthy and atretic follicles in different stages of cytomorphosis and degeneration. The aforementioned histological groups were also heterogeneous according to their hormonal profiles. Serum androgens, estrogens, and prolactin concentrations are significantly increased in DHEA-treated animals as compared with controls. There was no significant difference in follicle stimulating hormone between rats with cysts and rats without cysts after DHEA treatment. After 20 days of DHEA treatment, rats with CLs have very high levels of luteinizing hormone. Luteinizing hormone and prolactin levels are significantly higher in rats with cysts than in rats without cysts after 10 days of DHEA treatment. As has been shown in this inquiry, androgens and estradiol levels in rats with cysts after DHEA treatment are higher than those in rats without cysts after DHEA treatment. Therefore, this study suggests that the ovarian cystic condition developed after DHEA treatment in rats, is associated with higher levels of circulating androgens, estradiol, and prolactin.

Androgens↗
PubMed1991

Abnormal responses to orthostatic testing in children and adolescents with recurrent unexplained syncope.

Syncope in the pediatric age group is a frequent event. Most often the cause is readily apparent--i.e., orthostatic hypotension or a vasovagal event. However, there are a large number of children with frequent recurrent unexplained syncope. Neither history, physical examination, nor standard testing reveals a cause. One hundred four consecutive patients were evaluated by orthostatic testing after standard methods found no cause for the recurrent syncope. Forty-seven (44%) of these 104 patients had syncope produced by orthostatic testing. Twenty-six of the 47 (55%) became syncopal within 5 minutes of testing initiation and 21 of the 47 (45%) after 5 to 11 minutes of testing. These patients had an average decrease of 81.5 mm Hg in blood pressure and a 25 beat/min decrease in heart rate. Of 12 control subjects, none lost consciousness with standing times as long as 14 minutes. Pacing was ineffective in preventing syncope, as two patients with a previously implanted normally functioning pacemaker had recurrent syncope clinically. Syncope was also induced by orthostatic testing, with the pacemaker showing a normal response with pacing as the patient became bradycardic. The syncopal event produced by orthostatic testing occurred with a downward blood pressure trend and a narrowing of the pulse pressure without a significant increase in heart rate. This was followed by a sudden drop in blood pressure and then by bradycardia. There is a group of children and adolescents with recurrent unexplained syncope due to abnormal orthostatic control mechanisms. Orthostatic testing appears helpful in identifying these patients.

Adolescent↗
PubMed1991

Flow cytometric analysis of granulosa cells from developing rat follicles.

Immature rats were treated with diethylstilboestrol (DES) or pregnant mares' serum gonadotropin (PMSG) and forward angle light-scatter (FALS) and 90 degrees light-scatter (90 degrees LS) signals were used to measure the size and the granularity (internal organization) of the granulosa cells, respectively. The results confirmed the presence of two major populations of granulosa cells in the ovaries of both groups of rats, with the same percentage of larger cells in both treatments (52.3% in DES, 49.5% in PMSG). Since DES treatment brings about granulosa cell growth while PMSG treatment causes growth and differentiation, it is evident that there is heterogeneity in granulosa cell sizes during different states of growth and differentiation. There was also heterogeneity in sizes of granulosa cells harvested from follicles of small (less than 210 microns), medium (210-420 microns) and large (greater than 420 microns) diameter. Quadrant analysis of granulosa cells in various fractions collected from Percoll gradients suggested an increase in granularity in the small and large granulosa cell populations. Cell cycle analysis of small and large granulosa cell populations collected from large follicles of rats treated with PMSG indicated that each population was distributed in G0/G1, S and G2/M phases. These results demonstrate that populations of small and large granulosa cells exist in rat ovarian follicles during various stages of growth and differentiation.

Animals↗
PubMed1990

Swelling-induced changes in electrophysiological properties of cultured astrocytes and oligodendrocytes. II. Whole-cell currents.

Using whole cell patch-clamp recordings we have found that swelling cultured cerebrocortical astrocytes or mouse spinal cord oligodendrocytes by perfusing them with hypotonic medium induced inward currents at the normal resting potential of -60 mV. The currents in the oligodendrocytes were always less than for astrocytes. We examined the reversal potentials of these responses by rapidly jumping the holding potential to different values and measuring the currents. We found that the hypotonic medium-induced conductance increase was always preceded by a conductance decrease in the case of oligodendrocytes, but only sometimes preceded by a conductance decrease in cultured astrocytes. The reversal potential of the conductance increase for astrocytes was around -40 mV, while the conductance decrease had a more negative reversal potential of -60 mV or less. For oligodendrocytes the reversal potential for the conductance increase was around -50 mV while the conductance decrease had a reversal potential of -90 mV or less. This suggests that K+ conductance decreased in the initial phase, while the conductance increase was due to additional channel openings. Ion substitution experiments in the case of the astrocytes showed that the reversal potential was shifted to a more positive value when medium K+ was increased, but was unaffected when Na+ was substituted by N-methyl-D-glucamine or Cl- by D-glucuronate, when corrected for liquid junction potential changes. Thus, the channels opened in these cells are likely to include non-specific cation channels. It is of interest that the two cells show a difference in their responses, and in the case of astrocytes these are likely to be involved in the regulatory volume decrease processes documented in these cells.

Animals↗
PubMed1990

Risks of acute traumatic intracranial haematoma in children and adults: implications for managing head injuries.

OBJECTIVE: To determine the factors influencing the risk of an acute traumatic intracranial haematoma in children and adults with a recent head injury. DESIGN: Prospective study of incidence of risk factors in samples of patients attending accident and emergency departments and in all patients having an acute traumatic intracranial haematoma evacuated in one regional neurosurgical unit during 11 years. SETTING: Accident and emergency departments in Scotland or Teesside and regional neurosurgical centre in Glasgow. PATIENTS: 8406 Adults and children (less than or equal to 14 years) who attended accident and emergency departments and 1007 consecutive patients who had an operation for an acute traumatic intracranial haematoma. Data were complete in 8366 and 960 patients respectively. RESULTS: Overall, children were less at risk than adults (one in 2100 v one in 348 respectively). In both age groups the presence of a skull fracture and changes in conscious level permitted identification of subgroups of patients with widely differing degrees of risk. In children the absolute risk ranged from one in almost 13,000 without a fracture or altered conscious level to one in 12 for a child in a coma and with a fracture; the pattern was similar in adults, the risks in corresponding groups ranging from one in almost 7900 to one in four. CONCLUSIONS: Although children attending hospital after a head injury have a lower overall risk of a traumatic haematoma, the main indicators of risk, a skull fracture and conscious level, are the same as in adults, and the pattern of their combined effect is similar. Guidelines for managing adults with recent head injury may therefore be applied safely to children; with the increasing provision of facilities for computed tomography they should be revised to ensure early scanning of more patients with head injury.

Acute Disease↗
PubMed1990

CT scanning and surgical treatment of 1551 head injured patients admitted to a regional neurosurgical unit.

Computed tomographic (CT) scans of 1551 recently head injured patients transferred to a regional neurosurgical unit (NSU) were reviewed. Some 90% of first scans were done outside normal working hours. More than a third of first scans were normal including a fifth of the patients who were in deep coma. Haematoma was found in 50%, contusion 28%, shearing injuries 13% and general swelling in 9%. In 22% the first scan led to urgent surgical evacuation of an intracranial haematoma. More than one scan was done in 41% of patients and more than two in 10%, making 2608 scans in all. Repeat scans were more often done when the first scan was abnormal. In only five of 554 patients (1%) whose first scan had been normal were contusions or haematomas seen on subsequent scans, and in none of these was surgery required. Of 997 patients whose first scan had been abnormal a new lesion (contusion, haematoma and/or infarction) was seen on a subsequent scan in 103 cases (10%). Surgery was required (for the first time), in 57 patients whose abnormal first scans had not indicated the necessity for surgery at that time. The implications of these and other findings for the scanning of recently head injured patients in general hospitals, as scanners become more widely available, are discussed in our accompanying paper on p. 88.

Brain Concussion↗
PubMed1990

Head injuries in accident and emergency departments. How different are children from adults?

STUDY OBJECTIVE: The aim of the study was to examine the differences between child and adult patients attending accident and emergency departments after recent head injuries. DESIGN AND SETTING: A retrospective survey based on existing case records from 23 Scottish accident and emergency departments for 1985 was compared with prospective data from one hospital over 9 months in 1984. PATIENTS: 3838 children under 15 and 4775 adults attended hospital with head injuries during the period analysed. MAIN RESULTS: Only 9% of children and 20% of adults had evidence of brain damage (altered consciousness on arrival, or history of altered consciousness with amnesia on arrival). Scalp lacerations were recorded in approximately 40% of both children and adults, more commonly in those without brain damage. Fewer children than adults had a skull x ray; in both age groups x rays were more often done if there was evidence of brain damage, headache, or vomiting, and less often when there was a scalp laceration. Only 11% of children were admitted compared with 20% of adults. Admission rates per 100,000 population per year were 4011 for children and 1473 for adults (1967 overall); admission rates for brain damage were 290 for children and 341 for adults (331 overall). CONCLUSIONS: These are the first population based estimates of frequency of head injuries presenting at accident and emergency departments, analysed by age, gender and cause of injury. They should be of value when planning services for the head injured.

Adolescent↗
PubMed1989

In vivo and in vitro effects of androgens on rat ovarian granulosa cells.

In this communication attention is called to some features of ovarian cyst formation in rats after exposure to 6 mg/100 gm body weight of dehydroepiandrosterone for 21 days. Cysts were identified by the transformation of mural granulosa cells into epithelial cells. The invaginations of the basal plasma membrane of the epithelial cells of the cyst are thought to be indications of the cells' involvement in active endocytosis. This endocytosis may be one strategy for moving fluid into the cyst. The filamentous actin of granulosa cells cultured in the presence of 10(-5) mol/L dehydroepiandrosterone was found to be deficient when compared with that of controls. This lack of filamentous actin coupled with other organelle degeneration is believed to lead to early atresia of granulosa cells in vitro in the presence of high concentrations of androgens.

Androgens↗
PubMed1989

Serum bioactive lactogenic hormone levels in women with familial breast cancer and their relatives.

Serum levels of bioactive lactogenic hormone (BLH), immunoreactive prolactin and growth hormone (ir-PRL and ir-GH) were measured in a group of familial breast cancer patients and their first degree female relatives and compared to those found in normal healthy women. The ratio of BLH to the sum of ir-PRL and ir-GH was slightly but significantly decreased in the familial breast cancer group (P = 0.018 by the Mann-Whitney U test) although there were no significant differences in the levels of BLH, ir-PRL and ir-GH between the two groups. No differences in the levels of the lactogenic hormones could be detected when the pre-menopausal women were considered separately or when 20 women from the familial group were compared to normal controls matched for age, parity, weight and menopausal status. The levels of BLH were highly correlated with the sum of ir-PRL and ir-GH in both the familial breast cancer group and the controls (P less than 0.001 for both groups by Spearman's rank correlation test). These findings are not indicative of the presence of an additional species of bioactive, but not immunoreactive, lactogen in the sera of women with or at high risk of breast cancer. However, the presence of different, but equipotent, forms of lactogen cannot be excluded in these women.

Adolescent↗