SPERM APOPTOSIS IN NONPREGNANT LUTEALPHASE SERA AFTER IN VITRO FERTILIZATION AS ASSESSED BY COMPARATIVE GENOMIC HYBRIDIZATION

Toxicity in serum has been reported in cases of recurrent spontaneous abortions and endometriosis. The null hypothesis was that serum toxicity was not involved in failed pregnancies after in vitro fertilization procedures. The objective was to expose donor sperm to pregnant versus nonpregnant patient sera and analyze for sperm DNA damaging effects using a novel comparative genomic hybridization method. Luteal phase sera (N = 21 cases) were drawn one week after embryo transfer. Colloid-washed donor sperm were incubated (48 h, 37 degrees C, 5% CO2 in air) in 0% or 50% sera. Single-stranded DNA (ssDNA) of control sperm were stained in Hoechst 33342 and hybridized to Sybr Gold-stained ssDNA of sera-treated sperm. Image analyses were performed and fluorescent intensities analyzed. Nonpregnant patient sera (57% of cases) were associated with DNA fragmentation (64.4 +/- 8.8 pixels; mean +/- S.E.M.) when compared with pregnant patient sera (106.3 +/- 8.4 pixels). There were no differences in the sera of biochemical (108.2 +/- 15.3) versus clinical pregnancy cases (105.3 +/- 11.4). The results suggest that nonpregnant patient sera contained factor(s) that cause DNA fragmentation leading to pregnancy losses.

CORRELATION OF SPERM PARAMETERS WITH APOPTOSIS ASSESSED BY DUAL FLUORESCENCE DNA INTEGRITY ASSAY

Failed fertilization after intracytoplasmic sperm injection or miscarriages occurs in cases involving apoptotic and necrotic sperm. Identifying normal sperm is important for successful assisted reproductive technologies (ART) procedures. The study was conducted to correlate sperm parameters with intact sperm with normal DNA assessed by the dual stain assay in 118 separate individuals. The results showed differences in percent DNA intact sperm in individuals with normal W.H.O. sperm features (62 +/- 1.1; mean +/- S.E.M.) compared with oligoasthenoteratozoospermia patients (38 +/- 5.3). Individuals whose sperm had fertilizing capacity had higher percentages of intact DNA (60 +/- 1.3 versus 47 +/- 2.4). The percentages of intact DNA sperm were significantly correlated to total motility in semen (R = 0.7), post-wash motility (R = 0.6), rapid progression (R = 0.6), intact acrosome (R = 0.5), and strict morphology (R = 0.5). There were no correlations with the remaining parameters. The dual stain assay identified sperm with normal physiology and fertilizing capacity. The dual stain assay measures DNA integrity and is a promising method to select normal sperm for ART.

A FOLLOW-UP EXPANDED STUDY OF THE CORRELATION OF SPERM VELOCITY IN SEMINAL PLASMA AND OFFSPRING GENDER

A preliminary study reported finding higher sperm velocity in seminal plasma in males of partners that conceived female offsprings. The null hypothesis was that sperm velocity was not related to the offspring gender. The objectives were: (a) to expand the previous study, and (b) to correlate offspring gender results with motility parameters determined through the computer-aided sperm analyzer (CASA) system. In combined fresh and frozen cycles (N = 187), sperm from cases with all female offsprings displayed higher curvilinear (48 +/- 1.0 mu/sec versus male 46 +/- 1.0, P < 0.05) and average path velocities (36 +/- 0.7 mu/sec versus male 34 +/- 0.7, P < 0.01). A criteria of less than 30 mu/sec or over 41 mu/sec average path velocity predicted 73 or 72% of the male or female offspring cases, respectively. A curvilinear velocity of less than 49 mu/sec or over 55 mu/sec predicted 58 or 59 % of the male or female offspring cases, respectively. Semen viscosity reflected in sperm velocity was linked to predominantly male or female sperm populations. Paracrine signals from the gender-skewed sperm precursor populations controlling viscosity merit further exploration.

Development of mammalian embryos exposed to mixed-size nanoparticles

Inhaled or ingested ultrafine nanoparticles and their effects on early pregnancy remain polemic. The objectives of the study were: (a) to determine the embryotoxic effects of nanoparticles at the 2-cell stage and (b) to localize the internalized nanoparticles in the blastocyst. Thawed mouse 2-cell embryos (no. = 128) were exposed to either mixed-size polystyrene-based nanoparticles (11 million/ml) or control G1.3 medium and assessed after 72 hours. Additionally, blastocysts (no. = 146) were exposed to nanoparticles and analyzed. The results showed that the nanoparticles did not inhibit 2-cell embryo development to the blastocyst stage (89.4 vs 96.8%; treated vs control). There were no differences in hatching (34.8 vs 43.5%), implantation (13.6 vs 24.2%) and degeneration (10.6 vs 3.2%). Delayed exposure to nanoparticles showed similar percent hatching (40.7 vs 47.3%) and implantation (17.6 vs 20.0%). Although nanoparticles were internalized, embryo development was not inhibited suggesting a lack of embryotoxicity. During hatching, the larger nanoparticles adhered to the extruding blastocyst, preferentially on trophoblasts, but interference was insignificant. Exposure to polystyrene-based nanoparticles at the concentration tested are not associated with embryonic loss.

Sperm velocity in seminal plasma and the association with gender of offspring

The gender of the offspring is determined by the fertilizing sperm. Previous gender studies were based on washed sperm, but not on sperm in seminal plasma. The objective was to correlate motility parameters assessed during semen analyses with the offspring gender. For comparison, fixed sperm head DNA quantitated by Hoechst 33342 fluorescence microscopy was also analyzed. Forty-six patients undergoing assisted reproduction procedures resulted in livebirth deliveries with either male or female-predominant offsprings. Sperm head fluorescence was weakly correlated to the gender in 61% of the cases. Sperm of patients with male offsprings had slower curvilinear (44.2 +/- 1.8 mean +/- SEM, versus, 49.9 +/- 2.7 micro /sec) and slower average path velocities (32.4 +/- 1.2 versus 36.3 +/- 1.7 micro /sec). Using cut-off values for the curvilinear (< 49 micro /sec) and average path (< 36 micro /sec) velocities of sperm swimming in seminal plasma, the two parameters predicted 75 and 68% of the male offspring births, respectively. The data suggest that sperm movement in seminal plasma is a marker for factors that skew the ratio of the X- to Y-sperm populations.

Cardiovascular effects of topical ophthalmic 10% phenylephrine in dogs

OBJECTIVE

To evaluate the effect of topical ophthalmic 10% phenylephrine on systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), pulse rate (PR) and electrocardiogram (ECG) in dogs.

ANIMALS STUDIED

Nine clinically normal dogs.

PROCEDURE

Arterial catheters were placed in the dorsal pedal artery of awake dogs and ECG leads were attached. After a 15-min acclimatization period, baseline PR, SAP, DAP and MAP were recorded every 5 min for 20 min. Two treatment groups (eight dogs each) were studied. Group I: one drop of phenylephrine was placed in each eye once. Group II: one drop of phenylephrine was placed in each eye three times at 5-min intervals. Following treatment, PR, SAP, DAP and MAP were recorded every 5 min for 90 min. The mixed procedure of the SAS system was used to perform a repeated measures analysis of variance to test for linear and quadratic trends across time.

RESULTS

Group I: There was a significant quadratic decrease in PR across time (P = 0.0051). Systolic arterial pressure increased linearly with time (P = 0.0002), MAP increased linearly with time (P = 0.0131), and DAP increased linearly with time (P = 0.0001). Group II: There was a significant quadratic decrease in PR across time (P = 0.0023). There was a significant quadratic increase in SAP (P = 0.0324), MAP (P = 0.0103) and DAP (P = 0.0131) across time.

CONCLUSIONS

Topical ophthalmic application of 10% phenylephrine in normal dogs results in elevation of arterial blood pressure and reflex bradycardia.

A comparison of heat-induced hyperactivation in patients' sperm after colloid or pentoxifylline wash methods

OBJECTIVE

Our purpose was to compare kinematic parameters of human sperm after processing through two different wash methods and 40 degrees C heat treatment.

STUDY DESIGN

Sperm specimens (N = 169 cases) were washed by either colloid or pentoxifylline wash methods, and the motility parameters were measured at either 37 degrees C or 40 degrees C at baseline (0 hours) and after 4 hours. Five randomly selected washed specimens with matching 37 degrees C (control) or 40 degrees C heat treatments were assessed for changes in a sentinel gene.

RESULTS

The percentage of sperm hyperactive motility was >5 times higher after the 40 degrees C heat treatment, in comparison with the 37 degrees C treatment, for both the colloid- and the pentoxifylline-washed sperm. The percentages of total motility and progression were equally enhanced in heated sperm for the two wash methods. No changes were detected in the sentinel gene with the heat treatment.

CONCLUSION

Sperm cells mildly heated at 40 degrees C responded with greater motility, progression, and hyperactivation. The data suggest that mild heat is a stimulus for sperm function because greater sperm hyperactivation is associated with increased sperm fertilizing capacity. The absence of change in the sentinel gene in heated sperm suggests that a temperature of 40 degrees C is too low to initiate alterations in the highly condensed sperm chromatin. More studies are needed before mild heating of ejaculated sperm becomes acceptable for use in assisted reproductive technologies.

Comet assay of cumulus cell DNA status and the relationship to oocyte fertilization via intracytoplasmic sperm injection

This paper postulates that in the ovary, the close association between the cumulus cells and the oocytes permits the fertilizing ability of the oocytes to be determined indirectly through cumulus cell DNA status. The objective was to use a modified comet assay to analyse cumulus cell DNA and relate the data to oocyte fertilization after intracytoplasmic sperm injection (ICSI) procedures. Oocytes were retrieved (n = 15 cases) and free-floating cumulus cells were pooled and smeared on clear glass slides to dry. Meanwhile, the denuded oocytes were injected with spermatozoa and fertilization was assessed, followed by embryo transfer. The fixed cumulus cells were stained in acridine orange, coated with a mini-gel agarose layer, lysed in alkaline buffer and electrophoresis performed. Analyses of fluorescent cell images (n = 449) showed that the tail moment was positively correlated to the percentage of fertilization after ICSI (r = 0.567, P < 0.05). In contrast, there was no correlation between tail moment and number of oocytes retrieved, total ampoules used, endometrial thickness and age of patient. The results suggested that the competence of the oocytes was associated with the cumulus cell DNA status. A unique feature here was the comet assay for archived material with obvious advantages.

Gonadotropin-releasing hormone and G proteins: potential roles in autoimmunity

The hypothalamic homone gonadotropin-releasing hormone (GnRH) displays gender-specific actions. Pituitary responsiveness to GnRH is generally increased by estrogens and decreased by androgens. GnRH is now known to be produced by the immune system and to exert potent immunologic actions. Our central hypothesis is that gender differences in responsiveness to GnRH in the immune system play a pivotal role in the gender differences in immunity and autoimmunity. Studies in lupus-prone mice demonstrate that GnRH exacerbates murine lupus in a gender-specific fashion. Subsequent studies from our laboratory suggest that the gender differences in immunologic responsiveness to GnRH may relate to differences in the expression of the signal transducers through which GnRH acts, namely, the G proteins, Gs, and Gq/11. We have further demonstrated gender differences in second messengers for GnRH, IP3, and cAMF in immune cells. We have also demonstrated that GnRH agonist increases the quantities and/or activity of G proteins in immune cells in a gender-specific fashion. We speculate that gender differences in GnRH production and action, and in G protein expression play a role in a variety of autoimmune diseases that affect females predominantly.

A simple comet assay for archived sperm correlates DNA fragmentation to reduced hyperactivation and penetration of zona-free hamster oocytes

OBJECTIVE

To correlate sperm variables with sperm DNA fragmentation, as assessed by using a modified alkaline comet assay for sperm smears.

DESIGN

The comet assay was adapted for fixed sperm smears (59 cases), and the level of DNA fragmentation was determined.

SETTING

Clinical and academic research environment.

PATIENT(S)

59 patients undergoing fertility treatment.

INTERVENTION(S)

Sperm samples leftover from IVF procedures were fixed and processed for the comet assay.

MAIN OUTCOME MEASURE(S)

Sperm head DNA density and sperm variables.

RESULT(S)

A correlation was observed between increased sperm head DNA fragmentation and decreased penetration of zona-free hamster oocytes. Heat-induced hyperactive motility decreased as DNA fragmentation increased. The DNA fragmentation did not correlate with percentages of intact acrosome, normality, maturity, and strict normal morphology.

CONCLUSION(S)

The advantages of the comet assay for archived cells include simplicity, low intraassay coefficient of variation, and low performance cost; in addition, DNA analysis can be carried out at leisure. Low DNA damage was associated with higher hyperactivation and oocyte penetration, suggesting that failed fertilization was linked to compromised DNA integrity in the sperm. Exploration of compounds to repair damaged DNA is warranted.

Roles of prolactin and gonadotropin-releasing hormone in rheumatic diseases

PRL is capable of influencing immune responses and is a cytokine in all likelihood. Circulating PRL is elevated in a number of autoimmune diseases, and about 20% of SLE patients are hyperprolactinemic. The serum PRL concentration often does not reflect disease activity in SLE. The PRL-suppressing drug bromocriptine has been reported to benefit small numbers of patients with reactive arthritis and inflammatory eye disease, and bromocriptine may be beneficial in treating SLE. In NZB/NZW mice, bromocriptine was beneficial and prolonged life. Bromocriptine therapy favorably modified disease in human SLE. In a preliminary open-label study, SLE patients treated with bromocriptine for 6 months had significant improvement in disease activity. These responses were corroborated by masted therapeutic studies. Daily treatment with low-dose bromocriptine prevented lupus flares, and bromocriptine was as effective as hydroxychloroquine in treating active nonorgan-threatening disease. The reports of the efficacy of bromocriptine treatment of SLE are encouraging. Additional studies may confirm the findings reported in this review and may lead to further use of hormonal modification to treat lupus and other autoimmune diseases. For the present, it is important to understand that treatment with dopamine agonists such as bromocriptine is experimental and best confined to therapeutic trials. In the experience of the authors, bromocriptine should not be relied on to treat severe life-threatening autoimmune disease. If bromocriptine is used to treat SLE and is then discontinued, the patient should be observed carefully for rebound hyperprolactinemia and the development of a lupus flare. GnRH is produced by lymphocytes and exerts immunomodulatory actions. Thus, GnRH resembles a cytokine. GnRH can be shown to exert gender-restricted immune actions in vitro and in vivo. The authors' preliminary observations are consistent with the possibility that gender-related differences in expression of the GnRH receptor or in GnRH signal transducers may contribute to gender-related differences in immune responsiveness to GnRH. These differences in G proteins may contribute to the gender-related differences in immunity and expression of autoimmune disease.

Growth during and after a trial of growth hormone releasing hormone 1-29 in children with idiopathic short stature or growth hormone neurosecretory dysfunction

The growth promoting effects of once nightly subcutaneous injections of growth hormone releasing hormone (GHRH) 1-29 (30 microg/kg) for 6 months were studied in 16 slowly growing prepubertal children with idiopathic short stature (ISS; Group 1) and 8 similar children with growth hormone neurosecretory dysfunction (GHND; Group 2). Each child underwent endogenous growth hormone evaluation using both pharmacological and physiological testing; each had stimulated values > 10 microg/l and were subsequently placed into one of two groups based on pooled 12-hour overnight GH of < or > or = 3 microg/l. Each patient was followed every three months for one year. There were no significant differences in the two groups throughout the study with the exception of the endogenous GH levels. Both groups responded to GHRH therapy with similar significant increases in their rates of growth. Although a subset of patients (6 of 21) continued to grow at a rate significantly greater than the pre-therapy rate of growth, overall rates of growth were not significantly different from the pre-therapy growth rates 6 months following the discontinuation of GHRH treatment. We conclude that GHRH 1-29, given in the doses provided, leads to similar changes in growth rates in short, slowly growing children who are GH sufficient and those with GHND. Despite prior reports to the contrary, GHND patients do not experience a sustained increased in growth rate upon discontinuation of GHRH.

Analysis of papillomavirus consensus L1 gene in a closed colony of baboons (Papio anubis)

OBJECTIVE

The purpose of this study was to analyze cervical specimens and semen from a closed colony of baboons for the presence of the papillomavirus consensus L1 gene.

STUDY DESIGN

Cervical swabs were collected from lightly anesthetized female baboons. Semen was collected from a male baboon by standard electroejaculation techniques. Deoxyribonucleic acid was extracted from the cells by two different methods and analyzed by polymerase chain reaction targeting the L1 consensus gene common for >25 genital papillomaviruses.

RESULTS

Analyses of the polymerase chain reaction-amplified products did not reveal bands for the papillomavirus in either the cervical specimens or the semen.

CONCLUSIONS

The hypothesis of a linkage between primates with papillomavirus as a common factor is not supported by the results of this study. This information is also important in assisting clinicians in setting up specific pathogen-free colonies of baboons.

Gonadotropin-releasing hormone increases CD4 T-lymphocyte numbers in an animal model of immunodeficiency

BACKGROUND

Gonadotropin-releasing hormone (GnRH) possesses immunostimulatory properties. We have previously demonstrated that GnRH antagonists decrease lymphocyte numbers in an animal model of autoimmune disease. We speculated that the converse might be true, that GnRH administration would increase lymphocyte numbers or alter lymphocyte subsets in an immunodeficiency state.

OBJECTIVE

Our purpose was to test the hypothesis that GnRH agonist would increase IgG and CD4 counts in a rat model of immunodeficiency independently of gonadal steroids.

METHODS

We used diabetes-prone (DP) BB rats. This model has been characterized to have an AIDS-like lymphocyte profile, with lymphopenia and depressed CD4 counts. Ovariectomized female DP rats were randomized to receive subcutaneous injections with GnRH or vehicle 6 times weekly. DR rats were ovariectomized and treated with vehicle as controls. We performed flow cytometric analysis and complete blood cell counts at baseline, 3.5 weeks, and 7 weeks of treatment. We also measured total serum IgG and luteinizing hormone levels.

RESULTS

GnRH administration significantly increased total serum IgG levels in DP rats compared with vehicle. The percentages of CD4(+) cells in blood were also significantly increased in the GnRH-treated group compared with the vehicle-treated group and compared with baseline. Similarly, the absolute numbers of CD4(+) positive T cells were increased over controls at 7 weeks. The effects of GnRH were specific for the CD4 subset because there were no significant differences in numbers of CD8(+) positive cells between the 2 treatment groups.

CONCLUSION

GnRH shows potential utility as an immunostimulatory agent in immunodeficient states manifesting diminished numbers of immunocompetent CD4(+) T lymphocytes.

Gender-specific exacerbation of murine lupus by gonadotropin-releasing hormone: potential role of G alpha(q/11)

We have previously demonstrated that GnRH and its analogues modulate the severity of murine systemic lupus erythematosus. In the present study, we demonstrate that GnRH alters disease severity in a sexually dimorphic fashion, even in gonadectomized mice. GnRH administration leads to an exacerbation of lupus in ovariectomized females, whereas it exerts no effect in castrated males. We initially hypothesized that gender differences in lymphocytic expression of GnRH receptor might explain these observations. Using competitive RT-PCR and binding studies to quantitate GnRH receptor expression in lymphoid organs, we found that GnRH administration led to decreased expression of GnRH receptor messenger RNA (mRNA) and GnRH binding, compared with vehicle, in spleens of ovariectomized females after 2 weeks of treatment. These decreases occurred concurrently with increased expression of interleukin-2 receptor mRNA and protein in females. GnRH administration did not alter GnRH receptor or interleukin-2 receptor mRNA or protein in castrated males. GnRH exerts actions on the pituitary through G protein signal transduction, specifically through G alpha(q/11). Competitive RT-PCR revealed that GnRH administration was associated with increases in the expression of G alpha(q/11) mRNA, compared with vehicle, in spleens in ovariectomized females but not in castrated males. Immunoblot analysis revealed a similar pattern. We conclude that gender differences in expression of G alpha(q/11) may contribute to gender differences in immunity and/or autoimmune disease.

Spermac stain analysis of human sperm acrosomes

OBJECTIVE

To study the association between low percentages of intact sperm acrosomes and fertilization failures in conventional IVF procedures.

DESIGN

A retrospective study.

SETTING

Clinical and academic research environment.

PATIENT(S)

Patients undergoing treatment of infertility.

INTERVENTION(S)

Sperm cells were fixed and stained using the Spermac stain.

MAIN OUTCOME MEASURE(S)

Percentages of intact acrosomes and fertilization.

RESULT(S)

There was a significant association between specimens with <40% intact acrosomes and failed conventional IVF procedures. Among the 29 cases with <40% intact acrosomes, 9 cases (31%) resulted in zero penetration of the oocytes. The mean (+/-SEM) percentage of fertilization was lower in the abnormal acrosome group (43.3% +/- 6.5%) than in the normal acrosome group (64.1% +/- 5.6%). The status of the sperm acrosome was not correlated with the results of fertilization in intracytoplasmic sperm injection procedures.

CONCLUSION(S)

Sperm with low percentages of intact acrosomes were associated with failed fertilization. The Spermac stain was useful for assessing acrosomes and identifying possible male factor infertility problems. The results suggested that a minimum percentage of sperm with intact acrosomes are needed for fertilization to occur in vitro.

Cyclical expression of GnRH and GnRH receptor mRNA in lymphoid organs

Gonadotropin-releasing hormone (GnRH) is known to possess direct immunomodulatory effects. We have previously demonstrated that the administration of GnRH analogues modulates the expression of murine lupus independently of effects on gonadal steroids. We speculate that GnRH exerts direct actions at the level of the immune cells. GnRH receptors have been identified on lymphocytes. Because GnRH and GnRH receptor (GnRH-R) expression varies with the estrous cycle at the levels of the hypothalamus and pituitary, we speculated that similar cyclicity might be demonstrable in lymphoid tissue. In this report, we used competitive reverse transcription PCR to quantitate the expression of GnRH and GnRH-R mRNA in lymphoid organs throughout the estrous cycle in mice. We demonstrate that the pattern of expression of GnRH-R mRNA in spleen agrees closely with the pattern in the pituitaries of the same mice and the pattern previously reported in the rat pituitary, with significantly increased levels of expression seen on the afternoon of proestrus compared to the morning of metestrus. A similar pattern is seen with GnRH-R mRNA expression in the thymus. Furthermore, we show that the expression of GnRH mRNA in both thymus and spleen agrees closely with the pattern of expression of its receptor, with significantly increased levels of expression seen on the afternoon of proestrus compared to the morning of metestrus. Additional in vitro studies demonstrate that both GnRH and estradiol significantly increase the expression of GnRH-R mRNA in immune cells. These findings support an active role for GnRH in the immune system.

Detection of pro-opiomelanocortin mRNA in human and rat caudal medulla by RT-PCR

Pro-opiomelanocortin (POMC) mRNA has been localized in the NTS of the rat, but not in the human or other species. Here, we report that RT-PCR amplification of human caudal medulla RNA generated a distinct band on agarose gels corresponding in size and sequence to the predicted 742-bp POMC PCR product. The 742-bp signal was undetectable following amplification of cortex, amygdala or caudate nucleus RNA. An homologous, 678-bp band was amplified from rat caudal medulla and, unexpectedly, from other brain regions. Competitive RT-PCR demonstrated that POMC cDNA from rat cortex, striatum and cerebellum was 17%, 22% and 45% of caudal medulla levels. These data indicate that the POMC gene is expressed in human caudal medulla and suggest that small amounts of POMC mRNA are present in regions other than the hypothalamus and NTS of rat brain.

Enhanced fertility after heat-induced hyperactivation

OBJECTIVE

To determine sperm hyperactivation, kinematic parameters, and fertilizing capacity after pretreating sperm at 40 degrees C for 4 hours.

DESIGN

Prospective study involving pooled donor sperm that were colloid washed and incubated at either 23 degrees C (control) or 40 degrees C (heat-treated) for 4 hours as pretreatment. After incubation, analyses were performed with a computer-assisted sperm analyzer, whereas separate portions of sperm were evaluated with the sperm penetration assay at 37 degrees C.

SETTING

Clinical and academic research environment.

PATIENT(S)

Cryopreserved-thawed sperm from different donors (n = 5).

MAIN OUTCOME MEASURE(S)

Sperm kinematic and fertilizing parameters.

RESULT(S)

Heat pretreatment of sperm resulted in over 22 times higher hyperactive motility at hour 4 compared with the control. The other kinematic parameters were also different. The heat-pretreated sperm group had a significantly higher percent penetration of zona-free oocytes with more swollen sperm heads per oocyte and enhanced sperm binding.

CONCLUSION(S)

The results showed that hyperactivation was induced by pretreatment of sperm with 40 degrees C heat, suggesting the involvement of heat factors in hyperactivation. The fertilizing capacity of sperm may be improved by the mild heat pretreatment when marked by the presence of heat-induced hyperactivation.

Heat-induced hyperactivation

PURPOSE

The objectives of this study were (1) to determine the sperm hyperactivation and related kinematic parameters at 40 degrees C after using four sperm wash procedures and (2) to correlate the heat-induced hyperactivation data with cases of clinical pregnancies from either artificial insemination or standard in vitro fertilization (IVF).

METHODS

Semen samples (n = 51) were collected by ejaculation, and semen analyses were carried out to determine the pretreatment data. Sperm kinematic measurements were performed using the Hamilton Thorn HTM-C computer-aided sperm analyzer. Hyperactivation was determined using the sort module on the HTM-C. Membrane integrity was assessed using the hypoosmotic sperm swelling procedure. Sperm morphology and acrosomal status were also determined using the Spermac stain. Each semen specimen was divided and processed through either the swim-up wash, the 1-h test-yolk buffer (TYB) wash, the 1 mg/ml pentoxifylline stimulant procedure, or the two-layer 90:47% gradient colloidal solution procedure. The washed sperm were incubated at 25 or at 40 degrees C for 4 hr. After incubation, kinematic parameters were assessed for the posttreatment data. Semen specimens were obtained on different occasions for artificial insemination or standard IVF. Data from intracytoplasmic sperm injection cases were not included to avoid confounding factors. Live births and/or pregnancies with fetal heart-beat examined by ultrasound were considered clinical pregnancies.

RESULTS

Heat-induced hyperactive motility was significantly higher in sperm of the male partner of pregnant (n = 7) patients compared with nonpregnant (n = 44) patients (mean +/- SE, 10.0 +/- 3.3 versus 5.5 +/- 0.8%) after TYB processing followed by 4 hr of incubation at 40 degrees C. This was also observed after colloid (Percoll) processing (11.6 +/- 4.6 versus 5.8 +/- 0.8%). There were no differences in hyperactivation after 4 hr at 23 degrees C between pregnant and nonpregnant cases. Parameters such as count, volume, motility, viability, and acrosomal status were not different for the groups. However, the percentage of sperm with normal morphology (WHO classification) was twice as high in the pregnant group versus the nonpregnant group.

CONCLUSIONS

Heat-induced hyperactivation was associated with fertile sperm and was predictive of pregnancy obtained after artificial insemination or IVF. The association was evident only after TYB or Percoll sperm processing. The study could not confirm the finding of significant decreases in motility after heat treatment of sperm derived from infertile males. The mechanism for heat-induced hyperactivation did not involve membrane integrity or the sperm acrosome, although an involvement of heat shock proteins was postulated. Interestingly, there were no pregnancies when sperm did not exhibit heat-induced hyperactivation.

Systemic and local effects associated with long-term epidural catheterization and morphine-detomidine administration in horses

OBJECTIVE

The purpose of this study was to determine the systemic and local effects associated with long-term epidural catheterization and epidural morphine-detomidine administration in horses.

STUDY DESIGN

Development of systemic or local effects was assessed by placing caudal epidural catheters in study horses and administering injections through the catheters every 12 hours for 14 days.

ANIMALS

Ten horses with epidural catheters that received daily injections; six uncatheterized horses presented for euthanasia.

METHODS

Horses received either 0.2 mg/kg morphine sulfate and 30 micrograms/kg detomidine hydrochloride or an equivalent volume of physiologic saline solution through epidural catheters. Systemic effects were compared between control and treatment horses by measuring physical parameters and hay and water consumption, as well as by evaluating major organs after euthanasia. Local effects were studied by examining cerebrospinal fluid and by grading representative samples of the spinal cord and surrounding tissues histologically for inflammation and fibrosis. Local effects were compared between control and treatment horses, as well as between catheterized (control plus treatment) horses and uncatheterized horses.

RESULTS

No significant difference was identified in daily variables or hay and water consumption between control and treatment horses. No growth was obtained from cerebrospinal fluid cultures. No significant difference in cerebrospinal fluid values or spinal tissue inflammation or fibrosis grades was shown between control and treatment horses. However, when compared with uncatheterized horses, cerebrospinal fluid red blood cell values were marginally higher and protein concentrations were significantly higher in the catheterized group. Lumbosacral and sacral spinal tissue segment inflammation grades, and sacral segment fibrosis grades were significantly higher in catheterized horses.

CONCLUSIONS

Long-term epidural administration of a morphine-detomidine combination is not associated with apparent adverse systemic effects in horses. Localized inflammation and fibrosis seem to be catheter-related.

CLINICAL RELEVANCE

Potential systemic and local effects are important considerations with long-term administration of a morphine-detomidine combination through indwelling epidural catheters for alleviation of chronic musculoskeletal pain in horses.

Efficacy of an epidural combination of morphine and detomidine in alleviating experimentally induced hindlimb lameness in horses

Amphotericin B-induced synovitis of the left tarsocrural joint was used to create a grade 3 of 4 lameness in 11 horses. Caudal epidural catheters were placed and advanced to the lumbosacral region. Baseline heart and respiratory rates were recorded and horses were videotaped at a walk and trot. Morphine sulphate (0.2 mg/kg) and detomidine hydrochloride (30 micrograms/kg) were administered to treated horses (n = 8) through the epidural catheter; an equivalent volume of physiologic saline solution was administered to control horses (n = 3) through the catheter. At hourly intervals after epidural injection for a total of 6 hours, heart and respiratory rates were recorded, and horses were videotaped walking and trotting. At the end of the observation period, video recordings were scrambled onto a master videotape. Lamenesses were scored by three investigators unaware of group assignment or treatment time. Lameness scores, heart rates, and respiratory rates were compared between groups using repeated measures analysis of variance. There was a significant decrease in lameness score after treatment with epidural morphine and detomidine (P = .0003); average lameness scores of treated horses were less than grade 1 at each hourly observation for 6 hours after drug administration. Early in the observation period, heart rates significantly increased in control horses and decreased in treated horses (P = .03). A similar trend occurred for respiratory rates (P = .07). Results of this study demonstrate that epidural administration of a combination of morphine and detomidine is capable of providing profound hindlimb analgesia in horses.

Analysis of the flow cytometer stain Hoechst 33342 on human spermatozoa

Several procedures exist for processing sperm cells for sex preselection. Flow cytometric separation using the fluorochrome stain Hoechst 33342, chemically known as bisbenzimide, is the most promising. The objective of this study was to determine the effect of bisbenzimide on spermatozoa assessed by means of the sperm survival test and to analyse the beta-globin gene in sperm DNA after exposure to increasing concentrations of bisbenzimide. Donor (n = 16) sperm specimens were pooled and washed in a discontinuous Percoll gradient 95:47%, divided and incubated in tubes containing bisbenzimide at concentrations 0 (control), 0.9, 9, 90, 900 and 9000 microM at 25 degrees C and scanned on a computer-aided sperm motility analyser at 0, 1, 4 and 24 h. Spermatozoa were also incubated in a known mutagen, ethidium bromide, as positive control. After 24 h of incubation, the treated sperm cells were processed through DNA extraction and polymerase chain reaction (PCR) performed with primers targeting the beta-globin gene. The amplified DNA products were analysed for evidence of mutation in 5% polyacrylamide gel electrophoresis and 20:80 denaturing gradient gel electrophoresis (DGGE) and further confirmed in 30:40 DGGE. The results showed complete cessation of motility in sperm incubated in the presence of 900 microM or higher concentrations of bisbenzimide. The beat cross frequency sperm parameter was significantly different at the 90 microM or higher concentration of bisbenzimide compared with the control. At concentrations < 900 microM bisbenzimide, there were no differences in the remaining sperm kinematic parameters (percentage rapid progressive, percentage total progressive, sperm velocities, linearity, straightness, amplitude of lateral head displacement and percentage hyperactive motility). PCR and DGGE analyses of spermatozoa treated with bisbenzimide showed no evidence of mutation in the representative region of the beta-globin gene at concentrations < 900 microM. The data suggest an inhibitory effect of bisbenzimide on human sperm motility at 900 microM or higher concentrations of bisbenzimide. The decrease in sperm motility and rapid progression were not due to changes in pH. Point mutation in the representative region of the beta-globin gene in human spermatozoa was detected only at high concentrations (> or = 900 microM) of bisbenzimide. The data suggest that incubating sperm in low concentrations of bisbenzimide (< 90 microM) for up to 24 h does not significantly affect all the sperm kinematic parameters including the beat cross frequency parameter when compared with the control.

Sperm kinetics and morphology before and after fractionation on discontinuous Percoll gradient for sex preselection: computerized analyses

The multiple-layer discontinuous Percoll density gradient centrifugation procedure is being used for gender selection and several reports suggested separation efficiencies of over 77%. The mechanism involved in the separation of X- and Y-bearing sperm using this method seems to be the difference in sperm head dimensions or motility but supporting data are inconsistent. The specific aims of the study were to evaluate the head dimensions of sperm at the upper and lower fractions after the 8-layer Percoll gradient procedure for sex preselection and to ascertain the kinematic parameters and tail lengths of sperm derived from the 2 separate Percoll fractions. Sperm cells were obtained from thawed donor specimens (N = 20) and were layered on top of the 8-layer discontinuous Percoll gradient, which ranged from 34 to 85% in increments of 7%. After centrifugation, the resuspended sperm cells derived from the upper and lower fractions of the Percoll gradient were analyzed on the Hamilton Thorn HTM-C analyzer for differences in sperm motility patterns and sperm head dimensions. Aliquots of sperm from the 2 fractions were fixed and stained using the Spermac stain, and the lengths of each sperm tail (N = 600) were measured on the HTM-C analyzer. Sperm derived from the bottom Percoll (X) fraction had a threefold higher (p < .05) percent motility when compared with sperm from the top (Y) fraction. Sperm derived from the bottom (X) fraction maintained the higher percentage motility after 24 h of incubation. The percent total progression, rapid progression, and hyperactivation were also significantly higher (p < .05) in sperm from the bottom (X) fraction. Similarly, the curvilinear (Vcl), average path (Vap) and straight line (Vsl) velocities were significantly faster in sperm (p < .05) from the bottom (X) fraction. In contrast, the percent linearity and straightness were significantly (p < .05) higher for the top (Y) fraction. Sperm from the bottom (X) fraction have shorter (p < .07) tail length (1.6% difference) when compared with sperm from the top (Y) fraction. Although the dimensions of the sperm head from the bottom (X) fraction were numerically greater than top fraction sperm, they were not significant (p > .05). The results suggest that bottom (X) fraction sperm derived from the 8-layer discontinuous Percoll gradient for sex preselection have higher motility, progression, and hyperactivation when compared with top (Y) fraction sperm. The bottom (X) fraction sperm have greater longevity in motility and have shorter tails, supporting earlier hypotheses of sex differences in sperm parameters. However, the present data do not support observations of differences in sperm head dimensions in sperm processed for sex preselection, and an inference of a larger sperm due to more chromosome material originating from the X chromosome cannot be made.

Correlation between intact sperm acrosome assessed using the Spermac stain and sperm fertilizing capacity

Accurate determination of sperm acrosomal status is important in fertility studies. The objective was to correlate the percentage of intact acrosome assessed using the new Spermac stain with the capacity of sperm to fertilize oocytes. Sperm specimens were processed either by centrifuge wash, 48:95 Percoll gradient or test yolk buffer (TYB) wash, and tested using the zona-free hamster oocyte assay. The results indicated a correlation between the percentage of sperm with intact acrosome reaction and the percentage of sperm penetrating the oocytes in the TYB-washed group. The data suggest the usefulness of the Spermac stain for assessing the acrosomal status and in predicting the fertilizing capacity of the sperm.

Chylothorax associated with constrictive pericarditis in a dog

Chylothorax was associated with constrictive pericarditis in a 6-year-old mixed-breed dog. Clinical signs included hepatomegaly, bilateral jugular pulses, muffled heart sounds, and dyspnea. Pleural effusion was identified on thoracic radiographs. Thoracentesis yielded 3 L of chylous effusion, confirmed by the cholesterol/triglyceride ratio (0.14). Echocardiography revealed a thickened pericardium, with numerous fibrin tags, which was suggestive of constrictive pericarditis. Central venous, right atrial, and right ventricular pressures were high and on right ventricular diastolic pressure tracings, the square-root sign, which is indicative of constrictive pericarditis, was evident. Exploratory thoracotomy and pericardiectomy were performed. Histopathologic findings were consistent with chronic non-suppurative pericarditis. The dog's condition improved after surgery. On reevaluation 11 months later, central venous pressure and results of physical examination and thoracic radiography were normal. On the basis of these findings, we concluded that chylothorax was caused by constrictive pericarditis in this dog. Chylothorax is often associated with disorders that have a poor prognosis, but if constrictive pericarditis can be identified as the cause of the chylothorax, exploratory thoracotomy and pericardiectomy can provide a cure.

Cardiorespiratory effects of four opioid-tranquilizer combinations in dogs

The cardiorespiratory effects of four opioid-tranquilizer combinations were evaluated in six dogs. The four combinations were administered to each dog in a randomized order. Buprenorphine (BUP; 0.01 mg/kg IV) or oxymorphone (OXY; 0.1 mg/kg IV) was followed in 10.4 +/- 1.3 minutes by midazolam (MID; 0.3 mg/kg IV) or acepromazine (ACE; 0.05 mg/kg IV). Nalbuphine (0.16 mg/kg IV) was administered 94.1 +/- 2.3 minutes after the tranquilizer was given. Heart rate (HR) and mean arterial blood pressure (MAP) decreased significantly (P < .05) after each combination. MAP was significantly lower with combinations using ACE. Most dogs panted after opioid administration; this was associated with increased minute volume (VM) and decreased tidal volume (VT). After administration of the tranquilizer, mean breathing rate and VM index (VMI) were significantly lower with ACE combinations. There were no significant changes in pH and blood gas variables after BUP-ACE. The other three combinations were associated with significant (P < .05) decreases in pH and increases in PaCO2. Mean PaO2 decreased significantly (P < .05) with OXY combinations but not BUP combinations. Dysrhythmias (atrial or ventricular escape complexes) were seen with each combination. HR increased significantly (P < .05) after nalbuphine in dogs receiving OXY, but not BUP. Dogs receiving OXY became more alert after nalbuphine on six of 12 occasions, whereas dogs receiving BUP became less alert on six of 12 occasions. OXY-ACE provided the most chemical restraint/sedation and BUP-MID provided the least.

Modulation of the expression of murine lupus by gonadotropin-releasing hormone analogs

Recent studies have suggested that hypothalamic and pituitary hormones may directly influence the immune system. One such hormone with immunomodulatory properties is GnRH. We hypothesized that GnRH and/or the gonadotropins might alter the severity of autoimmune disease through mechanisms distinct from their effects on gonadal hormones. This possibility was tested in a murine model of lupus. We assessed disease severity over time in intact and castrated, male and female, lupus-prone (SWR x NZB) F1 hybrid mice during treatment with GnRH agonist, GnRH antagonist, or vehicle. Compared to vehicle administration, GnRH antagonist administration significantly decreased total serum immunoglobulin G and anti-DNA antibodies in castrated male and female mice and significantly improved survival. In contrast, GnRH agonist administration exerted reciprocal effects in castrated mice, leading to early increases in serum anti-DNA and total immunoglobulin G levels. We conclude that GnRH and/or the gonadotropins can modify the expression of murine lupus independently of their regulation of gonadal steroid secretion.

Cardiorespiratory effects of glycopyrrolate-butorphanol-xylazine combination, with and without nasal administration of oxygen in dogs

Cardiopulmonary consequences of IV administered glycopyrrolate (0.01 mg/kg of body weight), followed in 11 +/- 2 minutes by butorphanol (0.2 mg/kg) and xylazine (0.5 mg/kg), were evaluated in 6 dogs, with and without nasal administration of oxygen (100 ml/kg/min). Glycopyrrolate caused significant (P < 0.05) increases in heart rate and cardiac index and significant (P < 0.05) decreases in stroke index. Subsequent administration of butorphanol and xylazine was associated with significant (P < 0.05) increases in systemic vascular resistance, mean arterial blood pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, PaCO2, venous admixture, oxygen extraction ratio, and hemoglobin concentration. It caused significant (P < 0.05) decreases in cardiac index, stroke index, breathing rate, minute volume index, oxygen delivery, and oxygen consumption. Mean arterial blood pressure, pulmonary vascular resistance, tidal volume index, and minute volume index were significantly (P < 0.05) higher when dogs were breathing room air. The arterial and venous PO2 and PCO2, and venous oxygen content were significantly (P < 0.05) higher, and the arterial and venous pH, and oxygen consumption were significantly (P < 0.05) lower when oxygen was administered. Pulsus alternans and S-T segment depression were observed in dogs of both groups. Ventricular premature contractions were observed in 1 dog breathing room air. All dogs were intubated briefly 15 minutes after administration of butorphanol and xylazine. Time to first spontaneous movement was 45 minutes. All dogs remained in lateral recumbency without physical restraint for 60 minutes.

White blood cells in semen affect hyperactivation but not sperm membrane integrity in the head and tail regions

The presence of high numbers of peroxidase-positive PML in ejaculated semen significantly reduced sperm HA, an important step leading to sperm capacitation. Sperm membranes at both the head and tail regions, as assessed by the hypo-osmotic viability parameter and the hypo-osmotic sperm swelling test, respectively, were not affected by peroxidase-containing leukocytes. Sperm motility was not affected, but sperm curvilinear and straight line velocity parameters were reduced in the presence of high concentrations of leukocytes in the ejaculate. The results suggested that the effect of leukocytes on sperm was through a reduction in sperm hyperactive motility but not through alterations in the sperm head and tail membranes.

Cardiorespiratory effects of induction and maintenance of anesthesia with ketamine-midazolam combination, with and without prior administration of butorphanol or oxymorphone

Cardiorespiratory effects of an IV administered bolus of ketamine (7.5 mg/kg of body weight) and midazolam (0.375 mg/kg) followed by IV infusion of ketamine (200 micrograms/kg/min) and midazolam (10 micrograms/kg/min) for 60 minutes was determined in 6 dogs. Ketamine-midazolam combination was administered to dogs on 3 occasions to determine effects of prior administration of IV administered saline solution (1 ml), butorphanol (0.2 mg/kg), or oxymorphone (0.1 mg/kg). The infusion rate of ketamine and midazolam was decreased by 25% for anesthetic maintenance after opioid administration. There were no significant differences in cardiorespiratory variables after saline solution or butorphanol administration; however, oxymorphone caused significant (P < 0.05) increases in mean arterial blood pressure, systemic vascular resistance, and breathing rate. Bolus administration of ketamine-midazolam combination after saline solution caused significant (P < 0.05) increases in heart rate, mean arterial blood pressure, cardiac index, mean pulmonary blood pressure, venous admixture, and significant decreases in stroke index, pulmonary capillary wedge pressure, arterial and mixed venous oxygen tension, arterial oxygen content, and alveolar-arterial oxygen gradient. Opioid administration was associated with significantly (P < 0.05) lower values than was saline administration for heart rate, mean arterial blood pressure, and arterial and mixed venous pH and with higher values for stroke index, pulmonary capillary wedge pressure, and arterial and mixed venous carbon dioxide tension. Prior oxymorphone administration resulted in the highest (P < 0.05) values for mean pulmonary blood pressure, venous admixture, and arterial and mixed venous carbon dioxide tension, and the lowest values for arterial oxygen tension, and arterial and mixed venous pH. Each treatment provided otherwise uncomplicated anesthetic induction, maintenance, and recovery.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of midazolam administered concurrently with ketamine after intravenous bolus or infusion in dogs

Midazolam, a water-soluble benzodiazepine tranquilizer, has been considered by some veterinary anaesthesiologists to be suitable as a combination anaesthetic agent when administered concurrently with ketamine because of its water solubility and miscibility with ketamine. However, the pharmacokinetics of midazolam have not been extensively described in the dog. Twelve clinically healthy mixed breed dogs (22.2-33.4 kg) were divided into two groups at random and were administered ketamine (10 mg/kg) and midazolam (0.5 mg/kg) either as an intravenous bolus over 30 s (group 1) or as an i.v. infusion in 0.9% NaCl (2 ml/kg) over 15 min. Blood samples were obtained immediately before the drugs were injected and periodically for 6 h afterwards. Serum concentrations were determined using gas chromatography with electron-capture detection. Serum concentrations were best described using a two-compartment open model and indicated a t1/2-alpha of 1.8 min and t1/2-beta of 27.8 min after i.v. bolus, and t1/2-alpha of 1.35 min and t1/2-beta of 31.6 min after i.v. infusion. The calculated pharmacokinetic coefficient B was significantly smaller after i.v. infusion (429 +/- 244 ng/ml) than after i.v. bolus (888 +/- 130 ng/ml, P = 0.004). Furthermore, AUC was significantly smaller after i.v. infusion (29,800 +/- 6120 ng/h/ml) than after i.v. bolus (42,500 +/- 8460 ng/h/ml, P < 0.05), resulting in a larger ClB after i.v. infusion (17.4 +/- 4.00 ml/min/kg than after i.v. bolus (12.1 +/- 2.24 ml/min/kg, P < 0.05). No other pharmacokinetic value was significantly affected by rate of intravenous administration.

Comparison of Telazol, Telazol-ketamine, Telazol-xylazine, and Telazol-ketamine-xylazine as chemical restraint and anesthetic induction combination in swine

The use of Telazol (T, tiletamine and zolazepam, 4.4 mg T/kg) alone, Telazol-ketamine (TK, 4.4 mg T/kg and 2.2 mg K/kg), Telazol-xylazine (TX, 4.4 mg T/kg, 2.2 mg X/kg), and Telazol-ketamine-xylazine (TKX, 4.4 mg T/kg, 2.2 mg K/kg, and 2.2 mg X/kg) as chemical restraint and anesthetic induction combination was compared in pigs. Forty mixed-breed healthy pigs (24.4 +/- 5.6 kg, mean +/- SD) were randomly assigned to the four treatment groups (T, TK, TX, TKX) with 10 pigs in each group. All the anesthetics were premixed by adding sterile water, ketamine, xylazine, or xylazine and ketamine directly into the Telazol vial and given as a single intramuscular injection. All four anesthetic combinations induced a rapid onset of sternal recumbency within 1.76 +/- 1.0 minutes and lateral recumbency within 3.02 +/- 2.2 minutes in pigs after intramuscular injection; there was no significant difference among treatments. The combinations TX and TKX induced analgesia (as evident by a lack of response to needle prick in the middle portion of the pinna and flank regions) duration of 29.0 +/- 11.0 and 36.0 +/- 12.2 minutes, respectively, and ability to tolerate tracheal intubation (as evident by lack of coughing and chewing response to a laryngoscope) for a period of 34.0 +/- 8.4 and 39.0 +/- 9.9 minutes, respectively. The combinations T and TK did not induce analgesia nor conditions suitable for intubation. Duration of lateral recumbency was 29.9 +/- 10, 33.1 +/- 6.9, 52.2 +/- 6.9, and 61.5 +/- 10.7 minutes in T-, TK-, TX-, and TKX-treated pigs, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiorespiratory effects of intravenous bolus administration and infusion of ketamine-midazolam in dogs

Twelve healthy dogs were used to determine the cardiorespiratory effects of i.v. administered ketamine (10 mg/kg of body weight) and midazolam (0.5 mg/kg). Half the dogs received a ketamine-midazolam combination (K-M) as a bolus over 30 seconds and the other half received the K-M as an infusion over 15 minutes. Induction of anesthesia by use of K-M was good in all dogs. Ketamine-midazolam combination as a bolus or infusion induced minimal cardiorespiratory effects, except for significant (P < 0.05) increases in mean heart rate and rate-pressure product. The increase in heart rate was greater in dogs of the infusion group. Mild and transient respiratory depression was observed in dogs of both groups immediately after administration of K-M, but was greater in dogs of the bolus group than in dogs of the infusion group. Duration of action of K-M for chemical restraint was short. Salivation and defecation were observed in a few dogs. Extreme muscular tone developed in 1 dog after K-M bolus administration.

Cardiovascular effects of intravenous bolus administration and infusion of ketamine-midazolam in isoflurane-anesthetized dogs

Cardiovascular effects of IV administered ketamine (10 mg/kg) and midazolam (0.5 mg/kg) were determined in 12 healthy isoflurane-anesthetized (1.7% end-tidal concentration) dogs. Six dogs received a ketamine-midazolam combination (K-M) as a bolus over 30 seconds and 6 dogs received K-M as an infusion over 15 minutes. Ketamine-midazolam combination as a bolus and an infusion caused early significant (P < 0.05) reductions in mean systemic blood pressure, cardiac index, and stroke index, which returned to baseline values near the end of the study. Heart rate decreased significantly (P < 0.05) in dogs of the infusion group and returned to the baseline value near the end of the study. One dog died after K-M bolus administration. Mean maximal decreases from baseline for systemic blood pressure, cardiac index, and stroke index were significantly (P < 0.05) greater in dogs of the bolus group than in dogs of the infusion group; therefore, cardiovascular effects of K-M after infusion were less severe than those after bolus. Base excess and pHa decreased significantly (P < 0.05) in the infusion group, although similar changes occurred in both groups. Four dogs were maintained with 1.7% end-tidal isoflurane to determine temporal effects of isoflurane; these dogs did not receive K-M. Increases in heart rate, cardiac index, stroke index, and left and right ventricular stroke work indexes were significant (P < 0.05) at various sample collection intervals, particularly during the later stages of the study. Isoflurane anesthesia effectively blocked the cardiostimulatory properties of K-M.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased expression of human leukocyte antigen-DR on pulmonary macrophages in bronchopulmonary dysplasia

We used an immunoperoxidase method to examine the expression of the immune activation marker HLA-DR on pulmonary tissue obtained at autopsy from 14 patients dying of bronchopulmonary dysplasia. Controls consisted of 16 age-matched, sex-matched children dying of noncardiac, nonrespiratory, noninfectious illnesses or as a result of motor vehicle accidents. We did not observe aberrant expression of HLA-DR on pulmonary endothelial cells. Positive staining appeared exclusively on macrophages. We quantitated the expression of antigen by counting the number of positive macrophages and total macrophages/monocytes per high power field. Bronchopulmonary dysplasia patients displayed significantly greater numbers of both positive and total macrophages compared with the control group (p < 0.05). The percent positive macrophages also was significantly higher in the bronchopulmonary dysplasia patients (p < 0.005). We also examined a group of patients dying with infant respiratory distress syndrome. There was no significant difference in number of total macrophages in this group compared with age-matched controls.

Effects of a 44-day administration of phenobarbital on disposition of clorazepate in dogs

The disposition of clorazepate, a benzodiazepine anticonvulsant, was determined in dogs after administration of a single oral dose of clorazepate (2 mg/kg of body weight) and after oral administration of clorazepate (2 mg/kg, q 12 h) concurrently with phenobarbital (5 mg/kg, q 12 h) for 44 consecutive days. Serum concentrations of nordiazepam, the active metabolite of clorazepate, were measured. After a single oral dose of clorazepate, maximal nordiazepam concentrations ranged from 569.6 to 1,387.9 ng/ml (mean, 880.2 +/- 248.9 ng/ml) and were detected 16.8 to 131.4 minutes (mean, 85.2 +/- 36 minutes) after dosing. After administration of phenobarbital for 44 consecutive days, maximal nordiazepam concentrations were significantly (P < 0.01) lower, ranging from 209.6 to 698.5 ng/ml (mean, 399.3 +/- 155.6 ng/ml) at 68.4 to 145.8 minutes (mean, 93 +/- 25.8 minutes) after dosing. Mean area under the curve (AUC) on day 1 (mean, 3.37 +/- 0.598 ng.min/ml) was significantly (P < 0.001) greater than AUC on day 44 (1.66 +/- 0.308 ng.min/ml). Oral clearance was significantly (P < 0.01) greater on day 44 (12.44 +/- 2.55 ml/min/kg), compared with that on day 1 (6.16 +/- 1.35 ml/min/kg). Values for area under the first moment curve, oral volume of distribution, mean residence time, and elimination half-life were not significantly altered by concurrent administration of phenobarbital. Administration of phenobarbital altered the disposition of clorazepate such that the amount of nordiazepam in circulation during each dose interval was significantly reduced. Adequate control of seizures in epileptic dogs, therefore, may require higher dosages of clorazepate when it is coadministered with phenobarbital.

Evaluation of accuracy of pulse oximetry in dogs

The accuracy of a pulse oximeter was evaluated over a wide range of arterial oxygen and carbon dioxide tensions, using 2 probes (finger probe and ear probe) and 2 monitoring sites (tongue and tail) in anesthetized dogs. The arterial oxygen saturation of hemoglobin (SaO2) measured directly with a multiwavelength spectrophotometer was compared with saturation estimated by pulse oximetry (SpO2). Linear regression analysis of the pooled data from 399 simultaneous measurements of SpO2 and SaO2 indicated a highly significant correlation of SpO2 with SaO2 (r = 0.97; P less than or equal to 0.0001). Although the mean difference (+/- SD) between SpO2 and SaO2 for pooled data was small (-0.06 +/- 6.8%), SpO2 tended to underestimate high SaO2 values (greater than or equal to 70%) and to overestimate low SaO2 values (less than 70%). When SaO2 values were greater than or equal to 70%, the ear probe applied to the tail was less accurate (produced a significantly greater SpO2-SaO2 difference) than the ear probe on the tongue, or the finger probe at either site. When SaO2 values were less than or equal to 50%, the finger probe applied at the tail was more accurate (produced significantly smaller SpO2-SaO2 differences) than the ear probe at either site. When SaO2 values were less than or equal to 70%, high arterial carbon dioxide tension (greater than or equal to 60 mm of Hg) was associated with greater overestimation of SaO2.

A comparison of end-tidal halothane concentrations measured at proximal and distal ends of the endotracheal tube in the horse

Measurements (n = 126) of end-tidal halothane concentrations were taken from 21 horses anesthetized for routine and emergency surgery. One hundred five paired values allowed comparison of gas samples taken near the oral end of the endotracheal tube (Y1) to samples obtained at the cuffed end of the endotracheal tube (Y2). Twenty-one paired readings were assessed to compare samples taken 25 cm beyond the cuffed end of the tube (Y3) to samples from Y1. Measurements were made at all locations at 15-minute intervals starting 30 minutes after beginning halothane. All measurements were made in triplicate at end-expiration, and both sites were sampled within 1 minute of each other. Halothane concentration was measured by rapid infrared analysis with a gas sampling rate of 150 ml/min and displayed as a digital reading. Calibration of the machine was checked regularly. The difference between readings (Y1-Y2 or Y1-Y3 = Sdif) was tested using general linear models and a significance level of p less than 0.05 was used. The variable Sdif was analyzed with respect to time, mode of ventilation, and type of recumbency; no effects of these variables were detected. The mean values (+/- SD) of 105 readings for Y1 and Y2 were 2.41 vol% (+/- 0.49) and 2.39 vol% (+/- 0.49) respectively, and the Pearson's correlation coefficient (Y1 vs Y2) was 0.96. The mean values (+/- SD) of 21 measurements for Y1 and Y3 were 2.31 vol% (+/- 0.27) and 2.32 vol% (+/- 0.28) respectively and the Pearson's correlation coefficient (Y1 vs Y3) was 0.98.

Anesthesia for head and neck surgery

Anesthesia in patients for surgery of the head and neck should begin with evaluation of the animal's medical history, laboratory data, and physical examination. This information plus knowledge of the physiologic changes induced by abnormalities and surgery of the head and neck provide the basis for selection of anesthetic regimens and techniques. The regimen should include drugs that produce minimal impact on organ systems, especially those systems lacking physiologic reserve because of disease. Establishment of a patent airway, protection of the airway, and control of ventilation should receive primary attention. Monitoring and support of cardiopulmonary function and maintenance of fluid volume and renal function are essential. The patient should be observed until protective reflexes return and recovery is complete. Postoperative pain should be managed with analgesics.

Real-time microcomputer-based analysis of spontaneous and augmented labor

In an attempt to develop a reproducible, objective measure of adequate uterine activity in labor, real-time measurements of intrauterine pressure amplitude and contraction frequency, interval, duration, and integral were made in 54 patients, 11 of whom received oxytocin augmentation. We determined the active pressure integral required per centimeter of cervical dilatation, expressed in kPa seconds, and the mean active pressure, expressed in kPa. The augmented group had a significantly higher mean active pressure integral per centimeter than those in normal labor (P less than .01). There was a trend, which did not reach statistical significance, for subjects who required oxytocin augmentation of labor to develop a higher mean active pressure than those in normal labor. However, the correlation of any uterine contractility index (Montevideo units, Alexandria units, mean active pressure) with progress in labor was poor. We conclude that women with dysfunctional labor require more uterine activity for progress in labor than women with normally progressing labor, and that the computer-derived "area under the curve" is not a better predictor of labor progress than Montevideo units.

A population-based study of maternal and perinatal outcome in patients with gestational diabetes

A prospective population-based study of gestational diabetes mellitus was done with 2272 patients to determine perinatal and maternal outcomes. A large data base was collected on all patients. Patients with gestational diabetes mellitus were older, shorter, heavier, and had more children than did the control group. The higher cesarean section rate in the patients with gestational diabetes mellitus was explained by their increased rate of repeat cesarean section compared with control patients. This was associated with increased infectious complications. Other maternal complication rates were similar in the two groups. Acceptable glucose control did not normalize birth weight percentiles in patients with gestational diabetes mellitus. Maternal weight at delivery was the only significant predictor of birth weight percentile in the group with gestational diabetes mellitus. Plasma glucose levels were a poor predictor of birth weight percentile. Factors associated with maternal obesity in well-controlled gestational diabetes mellitus may be more significant than glucose control in the development of large-for-gestational-age infants.

Modulation of the major histocompatibility complex antigen and the immunogenicity of islet allografts

Modulation of major histocompatibility complex (MHC) antigen by parenchymal cells and "passenger leukocytes" is a common feature of allograft rejection. To assess its significance we have examined the fate of antigen-presenting cell (APC)-depleted pancreatic islet allografts subsequent to increasing their expression of MHC antigens by in vitro exposure to the lymphokine interferon-gamma (gIFN). While most untreated grafts survived indefinitely, gIFN-exposed grafts were acutely rejected. Using in vitro islet cell-lymphocyte coculture assays, we attempted to dissect the underlying mechanism of enhanced islet cell immunogenicity resulting from gIFN treatment. We determined that gIFN exposure did not affect the capacity of islet cells to serve as APC for T lymphocytes, however islet cell exposure to gIFN was associated with enhanced vulnerability to allogeneic cytotoxic T lymphocyte (CTL) lysis in vitro by an CD5+ (OX-19+), CD8+ (OX-8+), CD4- (W3/25-), class I-restricted CTL. On the basis of these findings, we conclude that antigenic modulation can be a decisive factor in the survival of engrafted tissues by augmenting the interaction of the graft antigens with cytolytic effector T lymphocytes.

Prevention of recurrent diabetes in BB rats after islet transplantation by monoclonal antibody therapy

Two immune responses imperil pancreatic islet allografts transplanted into subjects afflicted with autoimmune diabetes: 1) the well-described allograft response that is mounted against tissues bearing foreign transplantation antigens and 2) a recurrence of the beta-cell-specific autoimmune process responsible for the primary disease. To define the role of autoimmune response to transplanted islets, the possibility of a rejection response must be prevented. To accomplish this in spontaneously diabetic BB rats, we induced neonatal tolerance. We found that recurrent autoimmunity in tolerant BB rats can be prevented by treatment of recipients with the monoclonal antibody OX8 (specific for cytotoxic T-lymphocytes) but not W3/25 (specific for helper T-lymphocytes). These findings provide direct evidence for the role of OX8-bearing lymphocytes in autoimmune diabetogenesis.

Prevention of recurrent autoimmune diabetes in BB rats by anti-asialo-GM1 antibody

BB rats exhibit a syndrome of spontaneous diabetes that has clinical and pathological characteristics analogous to those found in human insulin-dependent diabetes mellitus (IDDM). Islet tissue transplanted into spontaneously diabetic BB rats is uniformly destroyed by a recurrence of the autoimmune response that destroyed the diabetic subject's native islets. To examine recurrent autoimmune destruction of transplanted islets, it is necessary to exclude islet damage that might result from allograft rejection. We utilized neonatal tolerance induction to prevent rejection of Wistar-Furth (WF) (RT1u) islet allografts by spontaneously diabetic BB recipients. We determined that islet-recipient treatment with anti-asialo-GM1 (anti-AGM1) antibody prevents recurrent autoimmune diabetes that would otherwise destroy transplanted WF islet grafts. Anti-AGM1 therapy significantly decreased peripheral blood natural killer (NK) cell activity. These data suggest a role for NK cells in the pathogenesis of recurrent diabetes in neonatally tolerant BB rats.

Oxytocin augmentation of labor: a comparison of 15- and 30-minute dose increment intervals

Two different regimens for oxytocin augmentation of labor were compared retrospectively in two institutions. In one regimen, the interval between dose increments was 15 minutes; in the other it was 30 minutes. All study patients were nulliparous and had uncomplicated pregnancies in spontaneous active labor; the 15-minute group consisted of 92 patients and the 30-minute group had 82 patients. No differences were demonstrated in age, dilation when oxytocin administration started, length of oxytocin administration, cesarean section rate, complications of delivery, birth weight, or Apgar scores. The maximal oxytocin dose in the 30-minute interval group was significantly lower. This group also had the oxytocin infusion stopped for evidence of uterine hyperstimulation and/or abnormal fetal heart rate tracing significantly less often (6.9% for the 30-minute interval versus 17.8% for the 15-minute interval; P = .0017). Overall, these results suggest that the longer interval does not increase the length of labor but decreases the incidence of uterine hyperstimulation.