Effect of chronic treatment with the gonadotrophin-releasing hormone agonist azagly-nafarelin on basal concentrations of LH in prepubertal bulls.

Administration of GnRH agonist for an extended period inhibits pulsatile LH release but enhances testicular function of bulls. The mechanism whereby long-term administration of GnRH agonist enhances testosterone concentration in the blood of bulls has not been determined. The aim of this study was to determine whether chronic treatment with the GnRH agonist, azagly-nafarelin, increases blood concentrations of LH and FSH in prepubertal bulls. Two different doses of the GnRH agonist were administered via Alzet mini-osmotic pumps for 28 days. Blood samples were collected at 20 min intervals for 24 h at days 2, 13 and 25 of treatment. Agonist-treated groups had reduced testosterone pulse frequency (P < 0.05) and increased mean and basal concentrations of testosterone (P < 0.05) compared with untreated control bulls. Basal LH concentrations were higher in agonist-treated bulls during all three periods (P < 0.05) and overall (1 ng ml(-1) higher, compared with control bulls; P < 0.001). Frequency of LH pulses in the agonist-treated groups was reduced to less than one pulse in 24 h. Agonist-treated bulls tended to have (P < 0.10) or had (P < 0.05) a slight but significant increase in blood FSH concentration. In conclusion, the higher blood testosterone concentration in bulls after prolonged treatment with GnRH agonist may result, at least in part, from changes in the testes induced by enhanced basal concentration of LH.

When parties and candidates collide: citizen perception of house candidates' positions on abortion.

When candidates assume issue positions opposite those of their sponsoring political party do citizens recognize these positions? Relatedly, what role do candidates' actual issue positions play in citizens' perceptions of their issue positions? Examining citizens' perceptions of 1996 and 1998 House candidates' position on abortion, this research finds that citizens' perceptions are shaped largely by partisan and, to a lesser extent, gender stereotypes. However, candidates' individuating positions on abortion influence perceptions of the candidates' position, but the effects are considerably stronger for perceptions of Republican candidates. Democratic candidates are likely to adopt anti-abortion positions in districts characterized by lower than average levels of political awareness and education, reducing the likelihood their party-contradicting position is accurately perceived. In contrast, Republican candidates adopt a pro-choice position in districts characterized by high education and political awareness, increasing the likelihood their position is accurately perceived.

Influence of hypo- or hyperthyroidism on ovarian function in Brahman cows.

Multiparous Brahman cows (n = 21) were randomly assigned during late fall within BW and body condition score (BCS) to receive either 3.0 mL of corn oil (C; n = 7), 3.0 mg/(cow x d) triiodothyronine (T3) s.c. in 3.0 mL of corn oil (HYPER; n = 7), or 4.0 mg/(kg x d) 6-n-propyl-2-thiouracil (PTU; fed with concentrate) plus 3.0 mL/d corn oil (HYPO; n = 7). Water, minerals, and Coastal bermudagrass hay were available free choice, and all cows received 3.2 kg x cow(-1) x d(-1) of 5:1 corn:soybean meal concentrate. The feeding period extended through three normal estrous cycles. Blood samples were collected weekly during the first and second estrous cycle, or until d 42 for anestrous cows, and daily throughout the third cycle. Also, between d 9 and 14 of the third cycle, or after d 35 in anestrous cows, intensive samples were collected at 2-h intervals for 24 h. Serum T3, thyroxine (T4), and progesterone (P4) were measured in weekly and intensive samples, and cortisol, insulin, GH, and thyroid-stimulating hormone (TSH) were measured in intensive samples. The altered thyroid status of HYPER and HYPO cows was evident (P < .001) during the third estrous cycle in mean daily T3, T4, and intensive TSH (P < .001) concentrations. Changes in BW and BCS were influenced by treatment (P < .001). A greater (P < .001) proportion of HYPER cows exhibited abnormal cycle length, and three of seven cows became anestrous. For cows that continued normal cycles, treatment did not affect (P > .05) the number of follicular waves, diameter of the dominant follicle, diameter of the ovulatory follicle, or P4 profiles during the third cycle. Insulin and GH concentrations did not differ (P > .05) among treatments in intensive samples, but, mean cortisol was greatest (P < .02) in HYPER cows. For Brahman cows that maintained normal estrous cycles, induced hyper-or hypothyroid status did not influence ovarian function.

[Severe occlusive bilateral retinal vasculitis within the scope of seronegative systemic lupus erythematosus]. / Schwere okklusive Vasculitis retinae beidseits im Rahmen eines seronegativen systemischen Lupus erythematodes.

Retinal vascular manifestation is the most common form of ophthalmic involvement in patients with systemic lupus erythematosus (SLE). Most frequently these consist of cotton-wool spots with or without intraretinal hemorrhages. Although rare, a more severe retinal vaso-occlusive disease, termed retinal vasculitis, has been described. We report on a 37-year-old white female with a 13-year follow-up of chronic discoid lupus erythematosus, which suffered massive bilateral visual loss coincident with the systemic exacerbation of her disease (proteinuria, pneumonia, serositis, leucopenia). The diagnosis of SLE was established with reference to the revised ARA-criteria (American Rheumatism Association). Ophthalmoscopy and fluorescein angiography revealed the typical aspect of a SLE-associated vaso-occlusive retinopathy on both eyes with marked ischemia of the macula. Immediate maximal immuno-suppressive therapy, early performed panretinal photocoagulation and subsequent cryoretinopexy did not stop the progression of the disease. Six months after the initial event vascularisations of the disc and rubeosis iridis occurred, but no secondary glaucoma up to date. In this patient, the almost complete absence of characteristic autoantibodies and immunological markers was striking. The correlation with other lupus manifestations, different therapeutic concepts and prognostic factors in SLE-associated retinal vasculitis are discussed.

Expression of tenascin and fibronectin in the rabbit cornea after excimer laser surgery.

In order to investigate the effects of excimer laser surgery on corneal wound healing, 25 rabbits underwent anterior keratectomy at a depth of 100 or 300 microns with a Meditec MEL 50 excimer laser. After various intervals the animals were killed and the cornea excised and investigated immunohistochemically for the expression of extracellular matrix (ECM) proteins, fibronectin and tenascin. Fibronectin was shown to occur earlier than tenascin, and the two also had different distribution patterns. Wound depth showed no clear effect on the localization and time of ECM protein expression. This study indicates that corneal wounds caused by excimer laser radiation and those caused by mechanical surgery differ as to healing mechanisms.

Endothelial reaction to perforating and non-perforating excimer laser excisions in rabbits.

With an ArF excimer laser (193 nm, 750 mJ/cm2, 20 Hz) and a special slit-mask system, perforating and non-perforating linear keratectomies were performed in 55 rabbit corneas with a follow-up from 1 hour to 6 months. Varying the pulse number according to ablation rate (0.8 micron/pulse) and corneal thickness, four linear radial excisions (3 mm length, 70 microns width) of increasing depth (70%, 80%, 90%, 100% perforation) were produced. The corneas were processed for light microscopy, scanning and transmission electron microscopy, and vital staining of the endothelium. Except for mild cell contact alterations and discrete single cell damage in the 90% deep excisions, no endothelial damage could be detected after non-perforating keratectomies. Minute (less than 20 microns) and small (20 to 100 microns maximal diameter) perforations induced cell enlargement, formation of pseudopodia, rosette-like figures, multi-nucleated giant cells, and ultimately uniform reformation of the cell pattern (1 hour to 7 days postoperatively). Larger excimer laser defects of Descemet's membrane (greater than 100 microns) were overgrown by dedifferentiated endothelial cells producing a new PAS-positive basement membrane. Vital staining revealed the complete and stable reorganization of the endothelium over these lesions within 6 months. Our observations are similar to those reported on the endothelial repair process following other surgical manipulations (knife incisions, direct Nd:YAG-laser trauma) and support the applicability of excimer lasers for corneal trephination in patients.

[Corneal wound healing after perforating and non-perforating excimer laser keratectomy. An experimental study]. / Korneale Wundheilung nach perforierender und nichtperforierender Excimerlaserkeratektomie. Eine experimentelle Studie.

For clinical use of the excimer laser more detailed knowledge of corneal wound healing is necessary. With an ArF excimer laser (193 nm, 750 mJ/cm2, 20 Hz) and a special slit mask system perforating and non-perforating keratectomies were performed in a series of 55 rabbits with a follow-up from one hour to six months post-op. After enucleation the corneas were immediately processed for light microscopy, scanning and transmission electron microscopy and vital staining of the endothelium (trypan blue/alizarin red S). In perforating cuts the endothelial reaction consists of polymegathism, migration, formation of multi-nucleated giant cells, metaplasia-like proliferation and ultimately stable reformation of the cell pattern (1h to 42d). Epithelium fills the anterior wound gap within three days with subsequent regression of the plug. Fibroblastic activity in the adjacent stroma leads to cellular immigration, production of new collageneous lamellae and complete reorganization of the wound cleft (1d to 6m). Nonperforating excisions showed similar healing tendency of stroma and epithelium, but no severe endothelial damage could be detected. Compared with former studies using knife incisions our results do not reveal significant difference regarding epithelial and stromal wound healing events. The encouraging healing tendency of the endothelium--similar to regeneration after ultrasound and Nd:YAG-laser damage--also confirms the applicability of excimer lasers in corneal surgery.

Excimer laser keratoplasty. Part 2: Elliptical keratoplasty.

An excimer laser at 193 nm was used with a new "open mask system" to perform elliptical noncontact and nonthermal keratoplasties and corneal grafts in human cadaver eyes (Part 1 of this article, Ophthalmic Surg 1989; 20:262-267). By light microscopy the corneas showed sharp, unbeveled cut margins with nearly perfect apposition of the inner wound aspects. An elliptical shape may be better than a circular one, since the former closely approximates the cornea's normal elliptical outline, making it easier to fit corresponding areas of corneal graft to bed. Also, it provides a wider area of Bowman's membrane for anchoring sutures and relatively less volume of donor antigenic tissue.

Excimer laser keratoplasty. Part 1: Basic concepts.

A commercially available ophthalmic excimer laser was used with a new "open mask system" to perform noncontact and nonthermal excimer laser keratoplasty in 20 human and 40 pig cadaver eyes. Circular penetrating corneal trephinations and corneal grafts were performed with the excimer laser set at 193 nm. Light microscopy and scanning and transmission electron microscopy of the human and pig eyes demonstrated the high quality of excimer laser trephination (smooth wound margins that were approximately parallel to the optical axis of the eye), and the superior wound configuration and geometry.

[Configuration of corneal incisions with the excimer laser: an experimental study]. / Korneale Schnittkonfigurationen mit dem Excimerlaser: eine experimentelle Studie.

The potential applications of an ophthalmic excimer laser at 193 nm include its use as a precise trephine in keratoplasty procedures. In a series of 20 human autopsy and 40 pig cadaver eyes the histological and ultrastructural results of donor and recipient trephination and full-thickness corneal grafting using new mask systems were evaluated. In comparison with other beam delivery systems the "open mask system" allows the performance of excimer laser trephinations with reproducible wound configuration and geometry, with easy handling and high reliability. This technique enables the surgeon to surmount the mechanical limitations of cutting direction and makes non-circular trephinations possible.