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Biomedical subjects

E Palmer

Publications and source records attributed to E Palmer.

At least 181 records · Page 10Linked to original sources
PubMed1984

Y-encoded, species-specific DNA in mice: evidence that the Y chromosome exists in two polymorphic forms in inbred strains.

We have investigated the structure of the murine Y chromosome by first developing a novel method for specifically cloning Y-encoded DNA and then generating a library enriched for Y-specific DNA sequences. Three randomly chosen Y DNA clones were studied and found to share several interesting properties: all three are members of small Y-specific multisequence families; all three are mouse-specific; and all three probes detect Y-encoded restriction fragments that are polymorphic. Examination of polymorphic Y chromosome restriction fragments in male DNA from nine different inbred strains suggests that only two polymorphic forms of Y chromosomal DNA exist among inbred strains of mice.

Animals↗
PubMed1984

Time of ovarian follicular recruitment in cyclic pony mares.

An experiment was carried out on pony mares to establish the time of the oestrous cycle at which ovarian follicles are recruited for ovulation. In one group (n=7), the cycle was interrupted at the preovulatory stage by removing the preovulatory follicle; in another group (n=13) the cycle was interrupted at day 6 of the luteal phase by inducing luteolysis with a prostaglandin injection (PG). In a subgroup (n=7) of those given PG, the ovary not bearing the corpus luteum was removed at the time of injection. A further group (n=6) served as surgical controls. The interval to the next ovulation and blood concentrations of FSH were observed. Anaesthesia alone induced in preovulatory mares was followed by normal ovulation 2.5+/-1 days later. Removal of the preovulatory follicle delayed the next ovulation (14.6+/-2.1 days; P < 0.01). Following PG injection, the interval to ovulation was similar regardless of whether an ovary was removed (12.8+/-4.3 days) or not (10+/-4.1 days). This similarity occurred despite a large and prolonged rise in plasma FSH levels that occurred only in the hemiovariectomized group. In addition, the intervals found after PG injection did not differ from those found after ablation of the preovulatory follicle. These observations indicate that 1) in the presence of the early active corpus luteum or dominant follicle, follicles grow to a similar stage of development; 2) recruitment of the follicle due to ovulation occurs 12 to 14 days before ovulation; 3) limiting new follicular growth to one ovary does not affect the time course to ovulation; and 4) prolonged high FSH levels do not alter the time course or ovulation rate.

Journal Article↗
PubMed1984

Actin-based gelation of cytoplasmic extracts from brain tissue.

Incubation of rat brain cytoplasmic extracts under the conditions described in this paper results in the formation of three-dimensional gels. Ultrastructurally, these gels correspond to complex supramolecular structures formed by single microfilaments and by microfilament bundles. Analysis of protein composition indicates that cytoplasmic gels are composed of actin and several associated proteins. Among the latter class of components, we have identified polypeptides with molecular weights of 55,000 (55K), 140,000 (140K), and a set of two or three polypeptides with molecular weights in the range of 235,000-245,000 (235-245K). The 55K and 140K components do not seem to correspond to any previously identified actin-associated proteins, while the 235-245K polypeptides may correspond to the protein known as fodrin.

Actins↗
PubMed1983

Seasonal effects on ovarian follicular development in pony mares.

To define ovarian follicular kinetics in the equine ovary during anestrus and the breeding season, the follicular population of pony mares was investigated at mid-anestrus and at the beginning and end of the breeding season. There was a clear effect of season on the exit of reserve (primordial and initiated) follicles since at the beginning of the breeding season we noticed a higher mitotic index for the smaller preantral follicles, leading to an accumulation of small and medium antral follicles. In contrast, the ovaries sampled during anestrus or at the end of the breeding season were very similar; only preovulatory development was lacking in anestrous ovaries. However, atresia was unaffected by season.

Anestrus↗
PubMed1982

Monoclonal IgG to the inner capsid of human rotavirus.

Monoclonal IgG to the inner capsid of human rotavirus was produced by mice immunized with hybrid cells derived from mouse myeloma and the spleens of mice immunized with rotavirus. This IgG reacted with an antigenic determinant of mammalian rotaviruses that was not present on that of avian rotaviruses.

Animals↗
PubMed1982

Effect of the stage of the oestrous cycle on the follicular population in pony mares.

In the middle of the breeding season, 16 pony mares (n = 4 per day) were slaughtered on four different days (days 6, 14, 17 and the preovulatory day) of the oestrous cycle, day 0 being the day of the last ovulation. All the ovaries were examined histologically; the number, size and atresia (defined by granulosa cell pyknosis) of all follicles larger than 1 mm in diameter were studied, using a Kryotome-video recorder-TV system. Follicular distribution of all the sizes studied (1-5 mm, 5-10 mm, greater than 10 mm in diameter) was very similar in the right and left ovaries. However, compared to the other ovary, the ovary with a luteal structure had fewer (P less than 0.05) healthy follicles larger than 10 mm. All follicles larger than 10 mm in diameter at day 6 were atretic. At day 14, a group of normal follicles larger than 10 mm was found in all the animals, and number of follicles larger than 10 mm was significantly increased (P less than 0.01). The largest normal follicle has increased in size at day 17 compared to day 14. However, a significant increase in the number of follicles undergoing early atresia was observed (P less than 0.05). Except for the large preovulatory follicle, all the follicles larger than 10 mm were atretic just before ovulation. There was a relationship between the follicular population and the duration of the follicular phase; the number of normal follicles 1-10 mm in diameter and the duration of the follicular phase were highly correlated (R = -0.56; P less than 0.02).

Animals↗
PubMed1982

Ovarian follicular populations in pony and saddle-type mares.

Five pony and 5 saddle-type mares were used to compare total ovarian follicular populations between breeds. The animals were hemi-ovariectomized at the preovulatory stage during the breeding season and the ovary bearing the large preovulatory follicle was studied using histological techniques. Pony and saddle-type mares did not differ as to mean number of primordial follicles, mean number of growing follicles, the variability of these numbers and follicular distribution into various size classes. No difference was detected either in the initiation processes of follicular growth, oocyte growth, granulosa cell multiplication and follicular atresia. However, significant differences were found in the pattern of antral formation (P less than 0.01). The present data suggest that pony mares are a valuable tool for the study of follicular populations in equines. The main features of the equine ovary are the small number of follicles (35 950 primordial and 100 growing follicles) and the high individual variability of this number (5 600 to 75 000 primordial and 20 to 300 growing follicles).

Animals↗
PubMed1982

Further observations on the ultrastructure of human rotavirus.

The inner capsid layer of human rotavirus was found to preferentially break up into large ring-like morphological units. The outer capsid was found to be composed of capsomeres covered by a thin protein or glycoprotein covering. These capsomeres appeared to be broad headed and short stemmed, similar to the type of pin used to mark locations on a map (pushpin).

Capsid↗
PubMed1982

Phosphorylated and unphosphorylated forms of cardiac tropomyosin.

Cardiac tropomyosin from 20-day-old chick embryos is composed of three different polypeptides with the same molecular weight but different isoelectric points. These polypeptides, which are designated as alpha 1, alpha 2, and alpha 3, have identical peptide maps. In vitro, however, only polypeptide alpha 1 is synthesized in a reticulocyte lysate programmed with cardiac RNA. These results, together with the observations indicating that tropomyosin alpha 2 corresponds to a phosphorylated polypeptide, suggest that only tropomyosin alpha 1 corresponds to a primary translational product and that forms alpha 2 and alpha 3 are derived from alpha 1 as a consequence of posttranslational modifications.

Animals↗
PubMed1982

Seasonal and individual effects on ovarian and endocrine responses of mares to a synchronization treatment with progestagen-impregnated vaginal sponges.

The 8 saddle-type mares were treated with progestagen-impregnated vaginal sponges for 8 days and prostaglandin on the day of sponge removal. The treatment was given at random days of the cycle in April, May, July and September. Sponge insertion induced a sharp decrease in LH levels; at sponge removal, there was an immediate increase in LH and a large FSH rebound. Ovulation was synchronized 11 +/- 2 . 8 days (s.d.) after the end of treatment. In April the interval from sponge removal to ovulation was longer (14 days compared with 10 . 1, 10 . 7 and 10 . 2 days), the basal and peak LH levels lower, and follicular growth more delayed than in the 3 other months. In July, there was a prolonged oestrogen preovulatory rise and reduced FSH levels. Numerous individual differences were shown, but none was significantly linked to the interval from sponge removal to ovulation. Within the 3 months when response was unaffected by season, the interval from end of treatment to ovulation was correlated with progesterone (r = 0 . 45 and r = 0 . 50) and FSH (r = -0 . 48 and r = -0 . 49) levels at Days 5 . 6 and 7 . 8 after sponge insertion. This means that in treated mares that have an active corpus luteum at the end of treatment there will be low FSH levels at this time and ovulation will be late. A good prediction of the ovulation time after such a synchronization treatment must therefore take into account season, animal and time of treatment in the oestrous cycle.

Animals↗
PubMed1982

Ultrasonic echography in the mare.

Ultrasonic echography in the mare allows pregnancy diagnosis as early as Day 14 after ovulation. In the 1980 and 1981 breeding seasons, a total of 7438 examinations of 4688 mares were performed on several farms with the same apparatus. The accuracy of positive pregnancy diagnosis was estimated to be greater than 95% and of non-pregnancy diagnosis greater than 84%. When abnormal pictures of vesicles are found, it has to be decided whether it is a conceptus or a cystic structure. Most small vesicles do not develop, whereas large ones, deformed shapes, presence of some echoes, or a division inside the vesicle most often represent a growing conceptus or sometimes twins. Twinning rate in early pregnancy (before Day 30) lies between 2.6 and 2.8%. Twins are suspected when there are 2 vesicles of equal size (observed successively rather than simultaneously) (50-60% are confirmed), unequal size (less than 9%) or one oversized vesicle (23%), one of an irregular shape (5%) or a divided vesicle (33%). No effect of the month of mating on the rate of twin conceptions was found. Early pregnancy loss (between mean Days 23 and 43) was estimated at 5.3% and total embryonic loss (early and late) at 9%. Rate of embryonic death increased in proportion to the interval between the two successive diagnoses. No critical period of early mortality or effect of the reproductive status on embryonic or fetal mortality was found.

Animals↗
PubMed1981

Bilateral corneal dermis-like choristomas; an X chromosome-linked disorder.

A male child was born with bilateral corneal opacification. His maternal uncle and a male first cousin of the patient's mother also had been born with identical bilateral corneal opacification that was pathologically proven to result from corneal dermoids. Histopathological examination of tissue removed from the present patient at the time of lamellar keratoplasty revealed thickened, keratinized epithelium, absent Bowman's membrane, and dense, irregular bands of highly vascularized collagenous connective tissue. No adnexal appendages were identified. The remainder of the ocular and general physical examination results was normal. In view of these clinical and histopathological similarities, the diagnosis of corneal dermis-like choristomas was made. To our knowledge, this report is the first to describe a family with X chromosome-linked recessive transmission of this condition.

Choristoma↗
PubMed1981

A rapid technique for the histological examination of large ovarian follicles.

A rapid technique for counting and classifying large ovarian follicles of domestic animals is described. Using a cryostat, 250-micrograms thick sections were cut from the frozen ovary; an image of the surface of each ovarian section was recorded on videotape. By replaying the videotape, the largest profile of each follicle larger than 1 mm in diameter was readily identified and measured. The presence or absence of atresia was determined by applying standard histological methods to fragments of individual follicles taken from the frozen sections. The results obtained are similar to those found using previous methods and demand only one-quarter of the time.

Animals↗
PubMed1981

Brain actin synthesized in vitro undergoes two different and sequential posttranslational modifications.

The have studied the posttranslational processing of actin molecules synthesized in a cell-free system. The results of these experiments indicate that during the in vitro synthesis of the actins from rat brain the primary translational products undergo two different and sequential posttranslational modifications. These modifications are accompanied by slight changes in the isoelectric points of the proteins and can be detected by isoelectric focusing analysis. The same posttranslational modifications can be detected during the in vitro synthesis of chick embryo skeletal muscle actin. The evidence presented suggest that the first posttranslational modification may correspond to the methylation of a histidine residue, and the second modification most likely corresponds to the acetylation of the NH(2)-terminal amino acid residues of actin molecules.

Acetyl Coenzyme A↗