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Biomedical subjects

H Lambert

Publications and source records attributed to H Lambert.

At least 91 records · Page 5Linked to original sources
PubMed1991

Periovulatory calcium channel blockade enhances reproductive performance in an animal model for endometriosis-associated subfertility.

Current evidence suggests that peritoneal inflammatory cell hyperactivation may be the essential pathologic abnormality in patients with endometriosis-associated subfertility. In these experiments we utilized an animal model to evaluate the use of an immunomodulatory agent as an alternative treatment for endometriosis-associated subfertility. The right uterine horn of 12 golden hamsters was resected and 2 x 2 mm squares were explanted onto the left uterine mesentery. Controls included hamsters undergoing uterine horn resection without endometrial explantation (n = 6) and nonsurgically treated animals (n = 6). Ovulation induction was initiated 6 weeks postoperatively with 40 IU of pregnant mare's serum gonadotropin on day 1 and 40 IU of human chorionic gonadotropin on day 3. Groups of six explant-bearing hamsters and six nonsurgical control hamsters were treated with verapamil (250 micrograms/kg every 8 hours subcutaneously), a calcium channel-blocking agent known to inhibit macrophage activation, from day 1 to 48 hours after administration of human chorionic gonadotropin. Animals were then killed and the number of embryos and oocytes in left tube counted as a reflection of reproductive performance. Fertilization was completely inhibited in animals bearing uterine explants. Treatment with verapamil dramatically reversed this effect. These data suggest that periovulatory treatment with an immunomodulatory agent such as verapamil may be an effective alternative to conventional treatment for endometriosis-associated subfertility.

Animals↗
PubMed1990

Evaluation of antisperm complement-dependent immune mediators in human ovarian follicular fluid.

A "sandwich"-type radiolabeled antiglobulin assay using monoclonal anti-C5b-9 neoantigen and polyclonal anti-C5b-9 was used to evaluate the presence of terminal C complexes (SC5b-9 or MC5b-9) in the sera and ovarian follicular fluid (FF) from 45 infertile women. FF SC5b-9 was detectable in all clinical diagnostic categories. The mean SC5b-9 levels in FF and sera were 399 ng/ml (range 75 to 1350 ng/ml) and 798 ng/ml (range 0 to 2700 ng/ml), respectively. Twelve (26.6%) of the 45 FF samples had normal hemolytic C activity, and all FF (n = 44) samples initiated C8/C9-dependent lysis of sensitized sheep E coated with human C1-7. Human plasma IgG antisperm antibodies (ASA) were capable of activating C in 31 (72%) of 43 FF samples as detected by their ability to deposit MC5b-9 on human sperm. Sera from infertile women with ASA in their sera and FF impaired human sperm binding to human zona pellucida and binding and penetration of zona-free hamster oocytes in vitro. The discovery of SC5b-9 and MC5b-9 in ovarian FF implies that the interaction of ASA and C could have a deleterious effect on sperm during in vivo and in vitro sperm-egg interactions in women with antisperm antibodies.

Antigen-Antibody Complex↗
PubMed1990

Reduction of primary postoperative adhesion formation under calcium channel blockade in the rabbit.

Preliminary studies in a hamster model have demonstrated calcium channel blocking agents to be potent inhibitors of primary post-traumatic peritoneal adhesion formation. The present investigation was designed to extend these observations to an extensively studied model, the rabbit, and to evaluate the optimal route of administration of these drugs for intraabdominal surgery. Rabbits were subjected to a standardized traumatic lesion of the left uterine horn. Subsequently, animals were divided into the following treatment groups: subcutaneous vehicle control (n = 7), intraperitoneal (ip) vehicle control (n = 8), subcutaneous verapamil treatment (n = 6), low-dose (2.5 micrograms/kg/hr) ip verapamil treatment (n = 10), and high-dose ip (25 micrograms/kg/hr) verapamil treatment (n = 6). All animals were reexplored at 1 week postop for evaluation of adhesion formation (scale: 0 to 4+). Calcium channel blockade-treated animals formed significantly fewer adhesions (0.45) than controls (3.93) (P less than 0.01). There was no significant difference between animals treated with sc with verapamil sc and those treated with low- or high-dose verapamil ip (0.33 vs 0.20 vs 1.0). These data confirm our preliminary results, suggesting that calcium channel blockade potently modulates peritoneal healing and regeneration. Furthermore, intraperitoneal delivery and systemic administration appear equipotent in this model. Further study of these agents as potential adjuvants for intraperitoneal surgery is indicated.

Abdomen↗
PubMed1990

Peritoneal fluid from endometriosis patients affects reproductive outcome in an in vivo model.

The cause and importance of endometriosis-associated subfertility are a subject of dispute in reproductive endocrinology. To further study this phenomenon, we have established a model to test the effect of peritoneal fluid (PF) from endometriosis patients on early reproductive events in vivo. Sexually mature female golden hamsters were subjected to an ovarian hyperstimulation protocol and divided into groups that received the following intraperitoneal injections: (1) saline, (2) human serum albumin (HSA), (3) PF from fertile controls, and (4) PF from stage I/II endometriosis patients. Animals were killed on days 4 and 17; reproductive performance was assessed by the number of oocytes and embryos recovered on day 4 and the number of uterine swellings counted on day 17. Reproductive performance was significantly impaired by PF from endometriosis patients; animals treated with control PF and HSA did not differ from control. These data demonstrate a marked impairment of early in vivo reproductive performance under the influence of endometriosis PF. These results support a role for a soluble PF component as a mediator in the pathogenesis of endometriosis-associated subfertility.

Animals↗
PubMed1990

Heterologous transplantation of activated murine peritoneal macrophages inhibits gamete interaction in vivo: a paradigm for endometriosis-associated subfertility.

Macrophage hyperactivation has been postulated to be the pathologic aberration in patients suffering from endometriosis-associated subfertility. In this report an in vivo model for macrophage-mediated infertility is described. Populations of macrophages were obtained from an inbred strain of mice (Balb/C) as follows: (1) in vivo hyperactivated macrophages (harvested from donor mice treated with intraperitoneal thioglycolate); (2) hyperactivated macrophages deactivated ex vivo with the protein synthesis inhibitor emetine; and (3) basal state (nonactivated) macrophages obtained from untreated mice. Recipient mice underwent ovarian hyperstimulation with pregnant mare serum gonadotropins; 2 x 10(6) macrophages were transferred on the afternoon of stimulation day 3 before injection of human chorionic gonadotropin (hCG) and mating. Unfertilized oocytes and 4-cell embryos were counted on day hCG +2 as a reflection of reproductive performance. Heterologous transfer of in vivo hyperactivated macrophages, but not basal state macrophages, significantly inhibited fertilization. This effect was largely reversed by pretreatment with emetine. These experiments confirm the relevance of macrophage-mediated interference with early reproductive performance and provide a model for the development of alternative therapies (e.g., immunomodulation of the peritoneal fluid environment) for endometriosis-associated subfertility.

Animals↗
PubMed1990

Electroporation-mediated uptake of proteins into mammalian cells.

Proteins of up to 230 kilodaltons are taken up by chinese hamster ovary fibroblasts exposed to electroporation under conditions generally similar to those used to mediate DNA transfection. The uptake of catalase, ovalbumin, and histone H1 labelled with fluorescein was visualized by fluorescence microscopy. Under the same conditions, the uptake of colloidal gold particles (20 nm diameter) was visualized by electron microscopy. In optimum conditions, about 25% of the cells remained viable and grew normally and about 25% of these retained labelled proteins during two cycles of further growth. About 6 x 10(4) molecules of catalase were retained per cell. Proteins were taken up when presented to the cells up to 4 h after electroporation, suggesting that mechanisms other than classical electropore formation may operate in these conditions. The proteins were localized in the cytoplasm in a predominantly vesicular pattern and histone H1 entered the nucleus in some cells.

Animals↗
PubMed1990

Effects of epinephrine on hemodynamics and oxygen metabolism in dopamine-resistant septic shock.

The hemodynamic effects of epinephrine were prospectively studied in 13 patients with septic shock who remained hypotensive after both fluid loading and dopamine. Hemodynamic measurements were performed before and one hour after the start of epinephrine infusion. Systolic, diastolic, and mean arterial pressure increased in all patients (p less than 0.01). Cardiac index and systemic vascular resistance increased by 34 and 32 percent, respectively (p less than 0.05), but heart rate and pulmonary vascular resistance remained unchanged. There was a concomitant increase in oxygen delivery (p less than 0.01) and oxygen consumption (p less than 0.05), the magnitude of the latter being related to baseline lactacidemia (p less than 0.01). In view of the generally recognized physiologic goals of septic shock management, we conclude that epinephrine could be an appropriate alternative where fluid loading and dopamine have failed.

Adolescent↗
PubMed1990

Effect of interleukin-1 on gamete interaction and mouse embryo development.

Early stages of endometriosis have been shown to be associated with infertility. The pathophysiology of this relationship is unclear. To determine if interleukin-1 (IL-1), a peritoneal macrophage product, has any effect on gamete interaction and early embryo development, human recombinant IL-1 was added to the coincubation of gametes in the sperm penetration assay (SPA), human zona pellucida assay (ZPPA) and culture medium (Ham's F-10) used for processing semen samples with the layering method, with analysis of velocity and motility after 24 hours. IL-1 was also added to mouse embryos (two cells) cultured for 72 hours. The results showed that IL-1 caused impairment of SPA and ZPPA when compared to control medium, without significant alterations in sperm velocity and motility. Also, IL-1 demonstrated significant inhibition of mouse embryo development. These results help explain subfertility associated with early stages of endometriosis.

Animals↗
PubMed1990

Pentoxifylline, a methylxanthine derivative, prevents postsurgical adhesion reformation in rabbits.

Previous studies from our laboratory have demonstrated pentoxifylline to be a potent inhibitor of primary post-traumatic adhesion formation in a rodent model. To evaluate pentoxifylline in a situation more closely mimicking the events encountered in infertility surgery, we developed a model for adhesion reformation after lysis of pelvic adhesions. New Zealand White rabbits received a standardized primary traumatic lesion to the left uterine horn. One week later, a laparotomy was performed for evaluation (prescore) and subsequent lysis of adhesions. After closure, the animals were randomized to treatment with vehicle or subcutaneous pentoxifylline, 2.5 mg/kg, administered at 12-hour intervals for six doses. Seven days later, the rabbits were sacrificed and evaluated in a blinded manner to quantify adhesion reformation (postscore). Using a scoring scale from 0 = no adhesions to 4+ = most severe, the mean prescore was not different between pentoxifylline-treated and control rabbits (3.8 versus 3.9, respectively). However, the mean postscore (0.7 versus 3.7, respectively) was markedly reduced by pentoxifylline (P less than .001). These data demonstrate a marked inhibition of adhesion reformation after lysis of pelvic adhesions under the influence of pentoxifylline in rabbits.

Animals↗
PubMed1989

Identification and simultaneous determination of non-steroidal anti-inflammatory drugs using high-performance liquid chromatography.

An isocratic high-performance liquid chromatographic procedure is presented for the screening of plasma samples for the presence of sixteen non-steroidal anti-inflammatory drugs. Detection was achieved simultaneously at two wavelengths (254 and 370 nm) and the purity of the eluted peaks was tested using absorbance ratios at the two wavelengths; identification could thus be effective without interferences from substances of other pharmacological classes. The drugs were extracted simultaneously with diethyl ether after acidification and separated from each other on an octadecyl reversed-phase column using only one eluent, acetonitrile-0.3% acetic acid-tetrahydrofuran (36:63.1:0.9, v/v). The recovery, precision and reproducibility of the method were satisfactory as it allowed the determination of the drugs from infra- to supratherapeutic concentrations.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1989

[Treatment of severe hyponatremia by restricted water intake].

The outcomes of 23 patients admitted to a medical intensive care unit for severe hyponatraemia (less than 120 mEq/l) associated with neurological disorders were reviewed. All patients had restricted water intake combined with a sodium intake adjusted to the natriuresis, and some received a loop diuretic. The mean correction rate during the first 48 hours was slow (greater than 12 mmol/l.24 h) in 16 cases and fast (less than or equal to 12 mmol/l.24 h) in 7 cases. Following biochemical cure, 2 patients in the fast correction group had an unfavourable outcome: one died for an unknown reason, the other developed pontine myelinosis. A review of the literature did not provide evidence that a certain rate of correction was better than the other, but it showed that an excessive rise in natraemia or an overcorrection of hyponatraemia was dangerous. Slow correction of hyponatraemia, usually obtained with water intake restriction, may be recommended.

Adult↗
PubMed1989

Heat shock resistance conferred by expression of the human HSP27 gene in rodent cells.

Heat shock induces in cells the synthesis of specific proteins called heat shock proteins (HSPs) and a transient state of thermotolerance. The putative role of one of the HSPs, HSP27, as a protective molecule during thermal stress has been directly assessed by measuring the resistance to hyperthermia of Chinese hamster and mouse cells transfected with the human HSP27 gene contained in plasmid pHS2711. One- and two-dimensional gel electrophoresis of [3H]leucine- and [32P]orthophosphate-labeled proteins, coupled with immunological analysis using Ha27Ab and Hu27Ab, two rabbit antisera that specifically recognize the hamster and the human HSP27 protein respectively, were used to monitor expression and inducibility of the transfected and endogenous proteins. The human HSP27 gene cloned in pHS2711 is constitutively expressed in rodent cells, resulting in accumulation of the human HSP27 and all phosphorylated derivatives. No modification of the basal or heat-induced expression of endogenous HSPs is detected. The presence of additional HSP27 protein provides immediate protection against heat shock administered 48 h after transfection and confers a permanent thermoresistant phenotype to stable transfectant Chinese hamster and mouse cell lines. Mild heat treatment of the transfected cells results in an induction of the full complement of the endogenous heat shock proteins and a small increase in thermoresistance, but the level attained did not surpass that of heat-induced thermotolerant control cells. These results indicate that elevated levels of HSP27 is sufficient to give protection from thermal killing. It is concluded that HSP27 plays a major role in the increased thermal resistance acquired by cells after exposure to HSP inducers.

Animals↗