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Biomedical subjects

H Morton

Publications and source records attributed to H Morton.

At least 55 records · Page 3Linked to original sources
PubMed1982

Ovum factor: a first signal of pregnancy?

Previous studies have shown that, in the mouse, a factor is produced by the fertilized ovum within 24 h of mating. It cooperates with prolactin to stimulate ovarian production of component B or early pregnancy factor (EPF). This paper presents an initial characterization of the substance, termed ovum factor (OF). An indirect assay based on the rosette inhibition test for EPF has shown that OF is first released upon penetration of the ovum by the fertilizing spermatozoon. OF continues to be produced at least until blastulation. Processes which parthenogenetically activate the ovum are also capable of stimulating OF release from unfertilized ova. Gel filtration studies reveal that OF exists in multiple MW forms of approximately 160,000; 2,800; and 1,500. A substance with these characteristics has not been described previously; it may represent the first embryonic signal to the mother.

Animals↗
PubMed1981

Characterisation and subunit structures of the vicilin storage proteins of pea (Pisum sativum L.).

Investigations of the vicilin fraction of the storage proteins of pea (Pisum sativum L.) have shown that its major components are a number of protein species of Mr 170 000. Convicilin (Mr 280 000, composed of 71 000-Mr subunits) is a separable component of this fraction. The vicilin proteins are composed principally of approximately equal to 50 000-Mr polypeptides, but also contain a number of smaller polypeptides. The sub-unit polypeptide composition of vicilin changes during seed development quantitatively and qualitatively. Vicilin sub-units have been shown to be synthesised as polypeptides of Mr approximately equal to 50 000 by means of pulse-labelling experiments in vivo, and synthesis of vicilin in vitro directed by mRNA, polysomes and microsomes extracted from pea cotyledons in cell-free translation systems. Polypeptides then undergo two distinct types of proteolytic modification: (a) co-translational removal of a small polypeptide (Mr less than 1000); (b) 'nicking' of polypeptide chains in assembled vicilin molecules, which occurs more than 4 h after their initial synthesis. The basic structure of the vicilin molecule is thus a multimer, possibly a trimer, of approximately equal to 50 000-Mr subunits. The heterogeneity of the initially synthesised 50 000-Mr subunits accounts not only for the several different 50 000-Mr polypeptides found in vicilin, but also for the range of minor polypeptides, since the 'nicking' points will differ among subunits. It also accounts for the observed partial separation of vicilin into different molecular species, since different subunit combinations will give rise to molecules with different properties. Vicilin is also glycosylated and this is a source of further variation.

Chemical Phenomena↗
PubMed1981

High absenteeism.

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Absenteeism↗
PubMed1980

The immunological approach to pregnancy diagnosis: a review.

The developing embryo/fetus bears antigens which are foreign to the mother and it could be expected that immune rejection of the conceptus would occur. One of the reasons why the fetus is not rejected is because a depression of the maternal immune response takes place during pregnancy. Serum from pregnant animals of several species has been shown to contain a factor, early pregnancy factor (EPF), which is immunosuppressive. EPF has been detected as early as six hours after mating and its detection could aid diagnosis of early pregnancy in all species.

Animals↗
PubMed1979

Detection of early pregnancy in sheep by the rosette inhibition test.

The rossette inhibition test, an established test for determining the immunosuppressive potential of antilymphocyte serum, has been applied to the serum of sheep after mating. The rosette inhibition titre was much higher (12--26) in 7 sheep which were fertilized and remained pregnant for up to 21 days than in 5 sterile ewes mated with intact rams (8--10). The difference was apparent by 24 h after mating. One ewe had high titres for 6 days after mating but these then dropped and she returned to oestrus; early embryonic loss was suspected. Another ewe which returned to oestrus had consistently low titres. The results indicate that the rosette inhibition test can be used to detect fertilization, early embryonic death and continued pregnancy in sheep.

Animals↗
PubMed1979

A test for early pregnancy in sheep.

The rosette inhibition test has been used to detect an early pregnancy factor (EPF) in the serum of ewes. EPF was shown to be to be present within 72 h of mating and was still detectable after one month of gestation and in some cases after four months' gestation. The detection of EPF could be of value in the diagnosis of pregnancy in the ewe during the first month of gestation.

Animals↗
PubMed1978

Detection and separation of two serum factors responsible for depression of lymphocyte activity in pregnancy.

Studies using the rosette inhibition test have demonstrated a depression of lymphocyte activity in pregnant mice which occurs as early as 6 hr after fertilization and persists until just before delivery. This depression of lymphocyte activity is induced by two serum factors, the relative contributions of which vary with the time of gestation. The first, a high molecular weight early pregnancy factor, appears within hours of fertilization and then slowly declines in activity as gestation proceeds. The second, a lower molecular weight substance which cross-reacts with antiserum to human chorionic gonadotrophin, appears after the formation of the trophoblast at 4--5 days and persists until parturition.

Animals↗
PubMed1977

An early pregnancy factor detected in human serum by the rosette inhibition test.

Modification of maternal lymphocyte activity has been demonstrated early in pregnancy by the rosette inhibition test. Normal human lymphocytes showed a similar depression of activity after incubation in serum from pregnant women, indicating that the response was caused by a serum factor. This early pregnancy factor has been differentiated from other substances which appear later in pregnancy and which may also be involved in the suppression of the maternal response. The results of this investigation suggest that the early pregnancy factor may be necessary for the continued viability of the early embryo.

Antilymphocyte Serum↗
PubMed1976

Antilymphocyte serum: studies of the specificity of the rosette-inhibiting antibody in rabbit anti-mouse ALS.

In an investigation into the characteristics of the rosette-inhibiting antibody of antilymphocyte serum (ALS), rabbit anti-mouse ALS were assayed for antibodies against lymphoid cells from the spleen, lymph nodes and thymus of Quackenbush (Q) mice, and against spleen cells from athymic nude mice. The lymphagglutinating and lymphocytotoxic titres were similar with both Q and nude cells, and the titres showed no significant correlation with skin graft survival times in mice receiving the corresponding ALS. A significant depletion of peripheral blood lymphocytes occurred in animals receiving both an immunosuppressive and a non-immunosuppressive ALS, suggesting that the antibodies involved in this depletion are not significant in determining the immunosuppressive activity of ALS. In contrast, the rosette inhibition titres showed a significant correlation with graft survival times in the results obtained in tests using Q spleen, lymph node and thymus cells. No inhibition of rosette formation was obtained when using nude spleen cells. However, the numbers of spontaneous rosettes formed by both the mixed B and T cell populations from Q spleen were not significantly different from the numbers formed by the largely B cell population from nude spleen. These results confirm that the antibodies of ALS which are responsible for both the in vitro inhibition of spontaneous rosette function and the in vivo suppression of graft rejection are specifically directed against a T cell population, and it is suggested that the antibodies are related if not identical.

Absorption↗
PubMed1975

Puerperal endometritis: a prospective microbiologic study.

This study was undertaken to determine the flora in the endometrial cavity of two groups of puerperal patients: 47 afebrile control subjects and 27 with endometritis. A transcervical culturing technique designed to avoid cervical contamination and to preserve aerobes, anaerobes, and mycoplasma was employed, and bacterial colony counts were reported semiquantitatively. No difference was found in the flora of these two groups. Furthermore, the most common pathogenic organisms (in decreasing order of frequency) were peptostreptococci, peptococci, Bacteroides sp., gamma-streptococci, enterococci, beta-streptococci, alpha-streptococci, and E. coli.

Adult↗