Preimplantation embryo development enhanced by epidermal growth factor

PURPOSE

Enhanced embryo maturity and advanced stages of cleavage at the time of embryo transfer are associated with superior pregnancy rates in in vitro fertilization procedures. This study was performed to assess the potential usefulness of epidermal growth factor (EGF) to enhance the development of murine preimplantation embryos cultured in vitro. Two-cell stage mouse embryos were cultured for 72 hr with EGF at concentrations of 0.1 to 100 ng/ml. The percentage of embryos which developed to the expanded and hatching blastocyst stage at 72 hr was determined.

RESULTS

The percentage of fully expanded and hatching murine blastocysts at 72 hr was significantly higher following incubation with EGF at concentrations of 2 ng/ml (44 +/- 4.1%; P < 0.02), 20 ng/ml (41 +/- 3.2%; P = 0.04), 50 ng/ml (43 +/- 2.5%; P < 0.04), and 100 ng/ml (46 +/- 3.6%; P = 0.001) compared to controls. This effect of enhanced embryonic development by EGF was neutralized by coincubation with 1.0 micrograms/ml of anti-EGF antibody.

CONCLUSION

EGF at concentrations of 2 to 100 ng/ml significantly enhanced the percentage of expanded and hatching murine blastocysts at 72 hr.

Alternatively spliced fibronectin molecules in the wounded cornea: analysis by PCR

PURPOSE

To determine whether certain fibronectin isoforms participate in corneal epithelial wound healing, the authors used the polymerase chain reaction to detect different splicing patterns of the EIIIA segment of fibronectin mRNA in epithelial scrape-wounded cornea of rats.

METHODS

Specific fibronectin cDNA sequences synthesized from rat cornea with total RNA were amplified with various sets of synthetic oligonucleotide primers.

RESULTS

The authors detected both the EIIIA+ and EIIIA- fibronectin mRNA isoforms during corneal wound healing. The kinetics of corneal expression of both total fibronectin mRNA and the EIIIA- fibronectin mRNA isoform was polyphasic; an initial decrease was followed by an increase at 45 minutes, a second increase at 2 hours, and a third increase at 4 days after wounding. EIIIA+ fibronectin mRNA, not found in normal cornea, also was detected during healing.

CONCLUSIONS

The expression of total fibronectin mRNA and both the EIIIA+ and EIIIA- fibronectin mRNA is upregulated during corneal epithelial wound healing. The expression of EIIIA+ fibronectin mRNA during wound healing, a fibronectin isoform that was highly expressed in embryonic tissue, suggests that this fibronectin isoform is involved functionally in corneal wound healing.

Polymorphous ventricular tachycardia after intracoronary papaverine: a report of 3 cases

Three cases with polymorphous ventricular tachycardia following a standard dose of intracoronary papaverine during 102 measurements of coronary flow reserve are reported. This study suggests that all patients should be closely monitored while receiving intracoronary papaverine and that extreme caution should be employed when the drug is administered to patients with QT interval prolongation and poor coronary flow reserve.

Characterization of the DNA binding properties of polyomavirus capsid protein

The DNA binding properties of the polyomavirus structural proteins VP1, VP2, and VP3 were studied by Southwestern analysis. The major viral structural protein VP1 and host-contributed histone proteins of polyomavirus virions were shown to exhibit DNA binding activity, but the minor capsid proteins VP2 and VP3 failed to bind DNA. The N-terminal first five amino acids (Ala-1 to Lys-5) were identified as the VP1 DNA binding domain by genetic and biochemical approaches. Wild-type VP1 expressed in Escherichia coli (RK1448) exhibited DNA binding activity, but the N-terminal truncated VP1 mutants (lacking Ala-1 to Lys-5 and Ala-1 to Cys-11) failed to bind DNA. The synthetic peptide (Ala-1 to Cys-11) was also shown to have an affinity for DNA binding. Site-directed mutagenesis of the VP1 gene showed that the point mutations at Pro-2, Lys-3, and Arg-4 on the VP1 molecule did not affect DNA binding properties but that the point mutation at Lys-5 drastically reduced DNA binding affinity. The N-terminal (Ala-1 to Lys-5) region of VP1 was found to be essential and specific for DNA binding, while the DNA appears to be non-sequence specific. The DNA binding domain and the nuclear localization signal are located in the same N-terminal region.

Induction of donor-specific transplantation tolerance to skin and cardiac allografts using mixed chimerism in (A + B-->A) in rats

Mixed allogeneic chimerism (A + B-->A) was induced in rats by reconstitution of lethally irradiated LEW recipients with a mixture of T-cell depleted (TCD) syngeneic and TCD allogeneic ACI bone marrow. Thirty-seven percent of animals repopulated as stable mixed lymphopoietic chimeras, while the remainder had no detectable allogeneic chimerism. When evaluated for evidence of donor-specific transplantation tolerance, only those recipients with detectable allogeneic lymphoid chimerism exhibited acceptance of donor-specific skin and cardiac allografts. Despite transplantation over a major histocompatibility complex (MHC)- and minor-disparate barrier, animals accepted donor-specific ACI skin and primarily vascularized cardiac allografts permanently, while rejecting third party Brown Norway (BN) grafts. The tolerance induced was also donor-specific in vitro as evidenced by specific hyporeactivity to the allogeneic donor lymphoid elements, yet normal reactivity to MHC-disparate third party rat lymphoid cells. This model for mixed chimerism in the rat will be advantageous to investigate specific transplantation tolerance to primarily vascularized solid organ grafts that can be performed with relative ease in the rat, but not in the mouse, and may provide a method to study the potential existence of organ- or tissue-specific alloantigens in primarily vascularized solid organ allografts.

Expression of yeast hexokinase in pancreatic beta cells of transgenic mice reduces blood glucose, enhances insulin secretion, and decreases diabetes

It has been proposed that endogenous hexokinases of the pancreatic beta cell control the rate of glucose-stimulated insulin secretion and that genetic defects that reduce beta-cell hexokinase activity may lead to diabetes. To test these hypotheses, we have produced transgenic mice that have a 2-fold increase in hexokinase activity specific to the pancreatic beta cell. This increase was sufficient to significantly augment glucose-stimulated insulin secretion of isolated pancreatic islets, increase serum insulin levels in vivo, and lower the blood glucose levels of transgenic mice by 20-50% below control levels. Elevation of hexokinase activity also significantly reduced blood glucose levels of diabetic mice. These results confirm the role of beta-cell hexokinase activity in the regulation of insulin secretion and glucose homeostasis. They also provide strong support for the proposal that reductions in beta-cell hexokinase activity can produce diabetes.

Nitric oxide production in host-versus-graft and graft-versus-host reactions in the rat

The present study was designed to determine whether .N = O produced in vivo during the rejection of histoincompatible tissues might permit serum NO2-/NO3- levels to serve as markers of a rejection reaction. Rat syngeneic and allogeneic liver, heart, bone marrow/spleen cell, small bowel, skin, and sponge matrix grafts were performed and the stable end-products of .N = O, NO2-/NO3-, were serially assayed in the serum of the grafted animals. A significant rise of serum NO2-/NO3- levels in the allografted animals preceded the onset of clinical signs of rejection or graft-versus-host disease, with the exception of the skin and sponge matrix graft models, where elevated serum NO2-/NO3- levels were never observed. In all transplant models, normal serum NO2-/NO3- levels were observed at all times in animals that received syngeneic grafts. Furthermore, treatment of allograft recipients with the immunosuppressive agents FK 506 or cyclosporine A inhibited .N = O production. Determination of serum creatinine levels demonstrated that the elevated serum NO2-/NO3- levels were not caused by kidney dysfunction. Serum NO2-/NO3- levels might be useful early serum markers of the initiation of a rejection reaction or graft-versus-host disease when functional markers of graft dysfunction are not apparent.

Antihistamine effect of supplemental ascorbic acid and neutrophil chemotaxis

Renewed interest in the antihistamine action of ascorbic acid has emerged with the recently recognized immunosuppressive role of histamine. We examined the antihistamine effect of acute and chronic vitamin C (VC) administration and its effect on neutrophil chemotaxis in healthy men and women. In the chronic study, 10 subjects ingested a placebo during weeks 1, 2, 5 and 6, and 2 g/day of VC during weeks 3 and 4. Fasting blood samples were collected after the initial 2-week period (baseline) and at the end of weeks 4 and 6. Plasma ascorbate rose significantly following VC administration compared to baseline and withdrawal values. Neutrophil chemotaxis rose 19% (NS) during VC administration, and fell 30% after VC withdrawal, but these changes were not correlated to plasma ascorbate levels (r = 0.01). Chemotaxis was inversely correlated to blood histamine (r = -0.32, p = 0.045), and, compared to baseline and withdrawal values, histamine levels were depressed 38% following VC supplementation. Blood histamine and neutrophil chemotaxis did not change 4 hours following a single 2 g dose of ascorbic acid, although plasma ascorbate rose 150%. These data indicate that VC may indirectly enhance chemotaxis by detoxifying histamine in vivo.

[Relationship between different patterns of left ventricular hypertrophy and plasma norepinephrine and hemorheology in patients with essential hypertension]

The changes of plasma norepinephrine (NE) concentration and hemorheology in 60 patients with essential hypertension (EH) with different patterns of left ventricular hypertrophy (LVH) were observed. The results showed that a higher value in whole blood viscosity (WBV) at a shear rate of 230-s was found in concentric hypertrophy (CH) group; a significant increase in plasma NE was found in asymmetric septal hypertrophy (ASH) group. It suggests that CH appear to be a compensation adapting to the increase in afterload. Significant increase in plasma NE concentration may play an important role in the development of ASH in addition to the afterload.

Antipeptide antibodies that can distinguish specific subunit polypeptides of glutamine synthetase from bean (Phaseolus vulgaris L.)

The amino acid sequences of the beta and gamma subunit polypeptides of glutamine synthetase from bean (Phaseolus vulgaris L.) root nodules are very similar. However, there are small regions within the sequences that are significantly different between the two polypeptides. The sequences between amino acids 2 and 9 and between 264 and 274 are examples. Three peptides (gamma 2-9, gamma 264-274, and beta 264-274) corresponding to these sequences were synthesized. Antibodies against these peptides were raised in rabbits and purified with corresponding peptide-Sepharose affinity chromatography. Western blot analysis of polyacrylamide gel electrophoresis of bean nodule proteins demonstrated that the anti-beta 264-274 antibodies reacted specifically with the beta polypeptide and the anti-gamma 264-274 and anti-gamma 2-9 antibodies reacted specifically with the gamma polypeptide of the native and denatured glutamine synthetase. These results showed the feasibility of using synthetic peptides in developing antibodies that are capable of distinguishing proteins with similar primary structures.

Reconstruction of a large DNA fragment from coinjected small fragments by homologous recombination in fertilized mouse eggs

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Prevention of graft-versus-host disease following allogeneic bone marrow transplantation in rats using FK506

FK506 and cyclosporine were used for the prevention of acute graft-versus-host disease. Acute GVHD was induced in Lewis rats by total-body irradiation and subsequent reconstitution with allogeneic (ACI) bone marrow and spleen cells (BMTx). GVHD was assessed by both clinical and histologic parameters during the experiment duration of 60 days, and longer for selected animals. All untreated BM recipients died within 26 days from severe acute GVHD. GVHD was prevented with CsA during the period of immunosuppressive therapy, but it appeared within a few days afterward. FK506-treated BM recipients were also protected, but they had a markedly prolonged GVHD-free period after therapy was discontinued. Most such animals eventually developed GVHD but with notable exceptions. Maintenance therapy with doses of FK506 as low as 0.1 mg/kg every other day (1/20 of daily induction dose) was infallible insurance against delayed GVHD. The relevance of these findings to GVHD caused by lymphoid-containing solid organs such as the intestine was discussed.

FK 506 reverses acute graft-versus-host disease after allogeneic bone marrow transplantation in rats

Severe graft-versus-host disease was induced by transplantation of ACI rat bone marrow and spleen cells into irradiated Lewis rat recipients. Treatment with FK 506 or cyclosporine A (CsA) was started after clinical and histologic evidence of acute GVHD was present. A 14-day course of FK 506 at 1.0 mg/kg/day could rescue 100% of the animals suffering from GVHD. In contrast only one half of the animals treated with CsA at a high dose of 25 mg/kg/day recovered. After cessation of immunosuppressive therapy, FK 506-treated animals displayed a marked prolonged disease-free interval as compared to CsA-treated bone marrow recipients. Recurrence of the disease in these animals could be prevented when FK 506 treatment was continued after the induction period with a low maintenance dose of 0.1 mg/kg/day every other day.

Immunocytochemical Localization of Glutamine Synthetase in Organs of Phaseolus vulgaris L

Glutamine synthetase was localized in nodules, roots, stems, and leaves of red kidney bean (Phaseolus vulgaris L.) by immunocytochemistry. Affinity purified antibodies reactive with glutamine synthetase were prepared using purified nodule-enhanced glutamine synthetase. Immunogold labeling was observed in the cell cytoplasm in each plant organ. In nodules, the labeling was more intense in the infected cells than in the uninfected cells. No labeling was observed in nodule bacteroids, peribacteroid spaces, or in peribacteroid membranes, while previous reports of glutamine synthetase immunolabeling of legume nodules showed labeling in the bacteroid fraction. Significant labeling was observed in nodule proplastids which contained starch granules. Substantial labeling was also observed in leaf chloroplasts. No labeling was observed in other organelles including mitochondria, peroxisomes, and endoplasmic reticulum. Preimmune IgGs did not bind to any structure in the tissues examined.