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Biomedical subjects

R B Heap

Publications and source records attributed to R B Heap.

At least 55 records · Page 3Linked to original sources
PubMed1989

Immunofluorescent localization, by use of anti-idiotypic antibody, of monoclonal anti-progesterone antibody in the mouse uterus before implantation.

Mouse monoclonal anti-progesterone IgG1 antibody designated DB3 has an anti-fertility effect when injected into female mice shortly after mating. In BALB/c mice, pregnancy is blocked, probably as a result of progesterone withdrawal with inhibition of implantation. Rabbit polyclonal anti-idiotype raised against DB3 has been used in an indirect immunofluorescence method on frozen tissue sections to demonstrate the presence of DB3 on the surface of uterine luminal and glandular epithelia before implantation. DB3 was only detectable 30-60 h after a single parenteral injection (9 nmol antibody per mouse i.p. or i.v. at 32 h post coitum). Immunolocalization was both pregnancy-dependent and anti-progesterone antibody-specific, as it was not seen in pseudopregnant mice or mice treated with P3 (mouse myeloma IgG1 protein, using polyclonal anti-P3 anti-idiotype as a probe) or saline. The immunofluorescent reaction was completely blocked by addition of DB3 idiotype in vitro. The results indicate that anti-progesterone antibody binds to an antigen associated with luminal and glandular epithelia which may locally inhibit the uterine uptake of progesterone and disrupt the process of implantation.

Animals↗
PubMed1989

Neurotransmitters and lymphatic-vascular transfer of prostaglandin F2 alpha stimulate ovarian oxytocin output in sheep.

The mechanisms of lymphatic-vascular transfer across the ovarian vascular pedicle were studied in anaesthetized sheep 8-15 days after ovulation. [3H]Prostaglandin F2 alpha (PGF2 alpha), [14C]mannitol and [36Cl]Na were infused continuously into either a uterine lymphatic or a uterine vein and the kinetics of transfer into the adjacent utero-ovarian vein or ovarian plasma were studied. Transfer occurred according to the sequence [36Cl] greater than [14C] greater than [3H] indicating that PGF2 alpha is not transferred by rapid diffusion, as with [36Cl]Na, nor by a paracellular route, as with [14C]mannitol, but by a slower process probably involving facilitated diffusion. Transfer into the adjacent utero-ovarian vein or ovarian blood was greater when compounds were infused into a uterine lymphatic than into a uterine vein. Substantially more [3H]PGF2 alpha occurred in the adjacent corpus luteum than either of the other compounds after a lymphatic infusion. Intra-lymphatic infusion of PGF2 alpha stimulated the release of ovarian oxytocin but the effect was not confined to the adjacent ovary. Intravenous (jugular) infusion of PGF2 alpha failed to stimulate ovarian oxytocin secretion whereas close-arterial infusion into the ovaries was effective, and the possibility was investigated that any systemic effect of PGF2 alpha was mediated through neural mechanisms. Noradrenaline and acetylcholine were both effective in causing the release of ovarian oxytocin when infused close-arterially into the ovary. With infusions of acetylcholine, ovarian oxytocin secretion rate was increased over fivefold without any change in posterior pituitary release. Noradrenaline and acetylcholine produced a concomitant fall in ovarian blood flow, and neurotransmitter-induced ischaemia may have played a role in ovarian oxytocin release. The finding that PGF2 alpha infused into a uterine lymphatic stimulates ovarian secretion of oxytocin, and that the effect is bilateral whereas PGF2 alpha accumulation in ovarian tissue is unilateral, implies that its mechanism of action may not be solely directed at the luteal cell.

Acetylcholine↗
PubMed1988

Inhibition of pregnancy before and after implantation in rats with monoclonal antibody against progesterone.

A monoclonal antibody against progesterone completely blocked pregnancy when rats were injected intraperitoneally at 0.53 mumol/kg/day on days 1 and 2, or on day 11 of a first pregnancy. The antibody was equally effective when injected again during a second pregnancy. There was no evidence for anti-idiotypic antibody production even when the injection of a heterologous (mouse) antibody was repeated in a second pregnancy.

Animals↗
PubMed1988

Cardiovascular and metabolic responses during growth hormone treatment of lactating sheep.

Pituitary-derived bovine growth hormone (bGH) was administered to six lactating Friesland ewes for 7 d. There was no consistent galactopoietic response, with changes in milk yield varying from 0 to 33% during treatment compared with the pretreatment period. The major effect of bGH on the concentration of milk constituents was to increase fat by 14.2% (P less than 0.05). Treatment resulted in significant increases in arterial plasma concentrations of growth hormone, insulin-like growth factor I and glucose, with decreases in the plasma arterial concentrations of acetate and certain amino acids. There was a marked reduction in haematocrit and in haemoglobin concentration which took at least 3 d to recover. The arterio-venous difference across the mammary gland decreased for O2 during treatment and the veno-arterial difference for CO2 decreased after treatment. Mammary respiratory quotient therefore decreased significantly after bGH treatment. The results suggest that bGH exerts effects at a number of separate loci.

Acetates↗
PubMed1988

Anti-idiotypic antibody used for the localization of parenterally administered monoclonal anti-progesterone antibody in mice.

Affinity-purified rabbit and sheep anti-idiotypic antisera raised against mouse monoclonal anti-progesterone IgG1 antibody (DB3) or mouse myeloma IgG1 protein P3 (MOPC 21) showed high binding specificities to the respective idiotypes used for immunization as determined by RIA or ELISA. They have been used in an indirect immunofluorescent method to demonstrate the localization of parenterally administered idiotypes in pregnant or pseudopregnant BALB/c mouse frozen tissue preparations, at known stages post coitum after a single intraperitoneal or intravenous injection of DB3 or P3. DB3 was visualized on the surface of uterine luminal and glandular epithelia of pregnant mice 36 h after treatment; the localization was DB3-specific as it was not seen in mice treated with P3 (using sheep anti-P3 anti-idiotype as a probe) or saline. The fluorescent staining reaction in oviduct was weak and only appeared on the surface of the oviducal serosa (peritoneal side). Both DB3 and P3 were also localized in liver (granules of Kupffer cells), kidney (glomerular basement membrane), spleen (on the membrane surface of mononuclear cells in the white pulp), and peritoneal exudate cells (on the membrane surface). Staining could be completely blocked by the addition of the free idiotypes against which the anti-idiotypes were made but not by the unrelated idiotype. Anti-idiotypic labelling in vivo is more specific and selective than anti-whole immunoglobulin labelling.

Animals↗
PubMed1988

Progesterone assay by inhibition of reverse passive haemagglutination.

An assay for the steroid hormone progesterone is described based on the inhibition of the agglutination by progesterone-bovine serum albumin conjugate of red cells coupled with monoclonal antiprogesterone antibody (reverse passive haemagglutination). A low-affinity agglutination system produced the optimal sensitivity, capable of detecting less than 1 ng/ml steroid. This assay has the simplicity and sensitivity for a potential clinical test for placental or corpus luteum function. It also serves as a model for detection of other small ligands (drugs, hormones) by inhibition of reverse passive haemagglutination.

Animals↗
PubMed1988

Uterine vascular permeability, blood flow and extracellular fluid space during implantation in rats.

Vascular permeability to plasma proteins in uterine implantation and non-implantation sites (i.e. dye sites and non-dye sites) was assessed quantitatively by a method which accounts for steady-state volumes of distribution. Extracellular fluid volume and uterine blood flow were also determined. On both the evening of Day 5 and the morning of Day 6, vascular permeability to 125I-labelled human serum albumin, extracellular fluid volume and blood flow were significantly increased in implantation sites compared to non-implantation sites. Vascular permeability in implantation sites was increased significantly between Days 5 and 6, whereas that in non-implantation sites was unchanged. This increase in vascular permeability between Days 5 and 6 was not accompanied by further increases in extracellular fluid volume and blood flow. This result shows a dissociation between vascular permeability and extracellular fluid volume immediately after the onset of implantation and raises important questions as to whether the rat uterus undergoes a truly oedematous response at implantation as has been generally accepted.

Animals↗
PubMed1988

Efficacy and specificity of monoclonal antibodies to progesterone in preventing the establishment of pregnancy in the mouse.

Anti-progesterone monoclonal antibody prevents the establishment of pregnancy in BALB/c mice by the prevention of implantation when injected i.p. 32 h after mating. To determine the specificity of this effect, mice were injected with immune and non-immune purified mouse immunoglobulins. The results show that anti-implantation efficacy was due to high-affinity antibody which bound progesterone since two further mouse immunoglobulin (Ig) G1 preparations, mouse IgA and mouse IgM which failed to bind the steroid, had no effect on pregnancy rates. From a panel of anti-progesterone monoclonal antibodies, six with a high affinity (affinity constant, 0.24-0.80 litres/nmol) and specificity for progesterone were selected for additional studies. Anti-implantation efficacy for five antibodies was similar, with a 50% effective dose within the range of 0.8-2.0 nmol. Antibody reached high concentrations in plasma within 12 h after i.p. injection, and declined with a half-life of about 80 h. Purified F(ab')2 fragments of antibody also bound progesterone, but were less effective than the native molecule in blocking pregnancy. The results show that implantation in the mouse can be blocked by a high-affinity antibody that binds progesterone and which is removed from the blood at a slow rate.

Animals↗
PubMed1987

Lectin-binding characteristics of mouse oviduct and uterus associated with pregnancy block by autologous antiprogesterone monoclonal antibody.

Oviducts and uteri were removed from BALB/cJ and F1 (CBA/Ca X BALB/cJ) mice at known stages post coitum and following treatment with an antiprogesterone monoclonal antibody (DB3) or a non-specific immunoglobulin (DNP). Thin sections of tissue were prepared and reacted with fluorescent conjugates of a wide range of lectins to determine if saccharide alterations were associated with the pregnancy-inhibiting effect of the DB3 antibody in BALB/c, but not F1, individuals. The ampullary region of the DB3-treated BALB/c mice showed the most marked changes, with an almost total inhibition of lectin binding, particularly for N-acetylglucosamine residues. There was also a reduced affinity for a lectin reactive with N-acetylgalactosamine in the uteri of DB3-treated BALB/c mice, associated with an extended expression during gestation of this saccharide in the proximal region of the oviduct in such mice. These are the first biochemical alterations in reproductive tract epithelia to be associated with the efficacy of the DB3 antibody in preventing pregnancy.

Animals↗
PubMed1987

Anti-progesterone monoclonal antibody affects early cleavage and implantation in the mouse by mechanisms that are influenced by genotype.

Pregnancy was blocked by anti-progesterone monoclonal antibody in two inbred (BALB/cJ, CBA/Ca) but to a lesser degree in an F1 hybrid (CBA/Ca male X BALB/cJ female) or an outbred (Tuck's no. 1) stock of mice when antibody was injected intraperitoneally (i.p.) at 32 h post coitum (p.c.) using a dosage of 9.5-10.9 nmol. This different antifertility effect could not be explained solely by altered tubal transport in inbred mice since the rate of transport was slightly accelerated in one stock (BALB/c) but not in another (CBA). In crossbred mice tubal transport was not significantly altered by antibody treatment. At Day 3 (54-58 h p.c.), the majority of embryos in control mice were at the 4-cell and 8-cell to morula stages in inbred and crossbred stock, respectively, but after antibody treatment they were mainly at the 4-cell stage in all 4 stocks. At Day 4 (78-82 h p.c.) the majority of embryos in control females had reached the blastocyst stage in all stocks, whereas after antibody treatment they had reached this stage in crossbred stock and relatively few had progressed so far in inbred stock. The results indicate that there are two events in early gestation which are susceptible to passive immunization with anti-progesterone monoclonal antibody. The first of these occurs during cleavage shortly after the 4-cell stage when embryo development was arrested in two inbred stocks of mice. Antibody effects on cleavage were not direct since embryos cultured in the presence of high concentrations of antibody, or antibody saturated with progesterone, continued to develop in the normal way and formed blastocysts. The second event is the onset of implantation, an effect also influenced by genotype. The decidual cell reaction induced by intraluminal oil injection was blocked by antibody injected at 8 or 32 h p.c. in BALB/c females, but only when injected at 8 h, and not at 32 h p.c., in F1 hybrid females. The results show that there is a greater resistance in two crossbred stocks compared with two inbred stocks to the effects of passive immunization against progesterone in early pregnancy.

Animals↗
PubMed1987

Suppression by perchlorate of technetium-99m and iodine-123 secretion in milk of lactating goats.

Lactating goats were infused with either technetium-99m (99mTc) or iodine-123 (123I) together with chlorine-36 (36Cl) through an indwelling catheter previously placed in an external pudic mammary artery. The radioisotope infusions were repeated together with 100 mg of sodium perchlorate. There was a rapid transfer of 99mTc and 123I into milk, reaching a peak concentration 30 min after a 15-min infusion. The fractional secretion of 99mTc and 123I in milk was reduced by 70%-80% and 60%-66%, respectively, by perchlorate. The fractional secretion of 36Cl was not affected by perchlorate, and the shape of the 36Cl secretion curve differed from those of 99mTc and 123I, which were similar. It is probable, therefore, that the latter nuclides were secreted by a transport route different from that of chloride. Available data describing the secretion of 99mTc in human milk after pertechnetate administration was reviewed, and it was concluded that perchlorate pretreatment significantly reduced the secretion of 99mTc in human breast milk.

Animals↗
PubMed1987

Analysis of an anti-progesterone antibody: variable crystal morphology of the Fab' and steroid-Fab' complexes.

Anti-progesterone monoclonal antibodies are being used for structural studies of antibody-antigen interaction, for their ability to block pregnancy shortly after fertilization, and for hormone immunoassay. A mouse anti-progesterone monoclonal Fab' fragment has been crystallized in its native form and co-crystallized with seven different, but structurally related, steroids. The crystals show interesting preferences in their crystal morphology, depending on the bound steroid ligand. The X-ray crystallographic analysis of this Fab', complexed with a series of related steroid ligands, should reveal details of the chemistry of antibody-antigen union and provide insights into how steroids interact with proteins.

Animals↗
PubMed1986

Use of a new and rapid milk progesterone assay to monitor reproductive activity in the cow.

A new and rapid enzyme-amplified immunoassay (AELIA) has been developed for the measurement of progesterone in milk. The AELIA system is a non-isotopic method that gives results within 35 minutes. Milk progesterone concentrations measured in 10 cows sampled daily at various stages of the reproductive cycle were very similar to those recorded by a validated radioimmunoassay. The results show that the speed and sensitivity of the AELIA system would make it possible to diagnose pregnancy rapidly at about 24 days after insemination, to predict the onset of behavioural oestrus from decreasing progesterone values during the third week after a preceding oestrus, and to obtain a daily record of milk progesterone levels in animals treated for infertility of ovarian origin.

Animals↗