Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment.

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.

Training induces nonuniform increases in eNOS content along the coronary arterial tree.

Exercise training produces enhanced nitric oxide (NO)-dependent, endothelium-mediated vasodilator responses of porcine coronary arterioles but not conduit coronary arteries. The purpose of this study was to test the hypothesis that exercise training increases the amount of endothelial NO synthase (eNOS) in the coronary arterial microcirculation but not in the conduit coronary arteries. Miniature swine were either exercise trained or remained sedentary for 16--20 wk. Exercise-trained pigs exhibited increased skeletal muscle oxidative capacity, exercise tolerance, and heart weight-to-body weight ratios. Content of eNOS protein was determined with immunoblot analysis in conduit coronary arteries (2- to 3-mm ID), small arteries (301- to 1,000-microm ID), resistance arteries (151- to 300-microm ID), and three sizes of coronary arterioles [large (101- to 150-microm ID), intermediate (51- to 100-microm ID), and small (<50-microm ID)]. Immunoblots revealed increased eNOS protein in some sizes of coronary arteries and arterioles but not in others. Content of eNOS was increased by 60--80% in small and large arterioles, resistance arteries, and small arteries; was increased by 10--20% in intermediate-sized arterioles; and was not changed or decreased in conduit arteries. Immunohistochemistry revealed that eNOS was located in the endothelial cells in all sizes of coronary artery. We conclude that exercise training increases eNOS protein expression in a nonuniform manner throughout the coronary arterial tree. Regional differences in shear stress and intraluminal pressures during exercise training bouts may be responsible for the distribution of increased eNOS protein content in the coronary arterial tree.

Expression and activity of protein kinase C isoenzymes during normal and abnormal murine palate development.

Protein kinase C (PKC) plays a critical role in signal transduction, mediating various cellular events critical for normal development, including that of the palate. In vivo and in vitro studies suggest the relevance of the inhibition of PKC by the mycotoxin, secalonic acid D (SAD), to its induction of cleft palate (CP) in mice. In the present study, temporal and spatial expression and the activity of various PKC isoenzymes were studied in the control and SAD-exposed murine embryonic palate during gestational days (GD) 12-14.5 by western blotting, immunohistochemistry, and phosphotransfer assay. The Ca2+-dependent isoenzymes, PKC alpha and PKC betaII, showed significant expression on GD 12.0, which gradually decreased through GD 14.5, whereas PKC betaI and PKC gamma were negligible throughout. All Ca2+-independent isoenzymes (epsilon, delta, and zeta) were expressed more abundantly and, in contrast to the Ca2+-dependent ones, progressively increased with age. SAD failed to alter this pattern of expression but enhanced the phosphorylation of PKC epsilon throughout development. Immunohistochemical analysis revealed an isoenzyme-specific distribution of PKC between the epithelium and mesenchyme. As expected, SAD significantly inhibited the total Ca2+-dependent PKC activity in palatal extracts. Although total Ca2+-independent PKC activity in palatal extracts was unaffected by SAD, individual pure isoenzymes were either selectively inhibited (PKC zeta), stimulated (PKC delta), or unaffected (PKC epsilon) by SAD. These results show that PKC isoenzymes exhibit dynamic temporal and spatial patterns of expression and activity in the developing palate and that the induction of CP by SAD is associated with an alteration in their activation and/or activity.

Skeletal muscle biochemical adaptations to exercise training in miniature swine.

The primary purpose of this study was to test the hypothesis that endurance exercise training induces increased oxidative capacity in porcine skeletal muscle. To test this hypothesis, female miniature swine were either trained by treadmill running 5 days/wk over 16-20 wk (Trn; n = 35) or pen confined (Sed; n = 33). Myocardial hypertrophy, lower heart rates during submaximal stages of a maximal treadmill running test, and increased running time to exhaustion during that test were indicative of training efficacy. A variety of skeletal muscles were sampled and subsequently assayed for the enzymes citrate synthase (CS), 3-hydroxyacyl-CoA dehydrogenase, and lactate dehydrogenase and for antioxidant enzymes. Fiber type composition of a representative muscle was also determined histochemically. The largest increase in CS activity (62%) was found in the gluteus maximus muscle (Sed, 14.7 +/- 1.1 mumol.min-1.g-1; Trn, 23.9 +/- 1.0; P < 0.0005). Muscles exhibiting increased CS activity, however, were located primarily in the forelimb; ankle and knee extensor and respiratory muscles were unchanged with training. Only two muscles exhibited higher 3-hydroxyacyl-CoA dehydrogenase activity in Trn compared with Sed. Lactate dehydrogenase activity was unchanged with training, as were activities of antioxidant enzymes. Histochemical analysis of the triceps brachii muscle (long head) revealed lower type IIB fiber numbers in Trn (Sed, 42 +/- 6%; Trn, 10 +/- 4; P < 0.01) and greater type IID/X fiber numbers (Sed, 11 +/- 2; Trn, 22 +/- 3; P < 0.025). These findings indicate that porcine skeletal muscle adapts to endurance exercise training in a manner similar to muscle of humans and other animal models, with increased oxidative capacity. Specific muscles exhibiting these adaptations, however, differ between the miniature swine and other species.

Regional changes in capillary supply in skeletal muscle of high-intensity endurance-trained rats.

The objective of this study was to test the hypothesis that an endurance training program designed to produce recruitment of all extensor muscle fiber types during each exercise bout would stimulate capillary angiogenesis throughout rat gastrocnemius and soleus muscles. Male Sprague-Dawley rats were exercise trained 5 days/wk for 12-14 wk with exercise bouts consisting of a combination of high intensity (32 m/min on a 15% incline) and long duration (90 min/day). On completion of high-intensity endurance training (HIET) or cage activity [sedentary (Sed)], rat hindquarters were vascularly isolated and perfusion fixed with a modified Karnovsky's fixative. Capillary supply was measured in soleus and gastrocnemius muscles by using Olympus Cue 2 image-analyzer software. Capillary supply was reflected in measurements of capillary-to-fiber ratio, capillary numerical density, capillary surface area density, and capillary volume density on transversely cut tissue sections. HIET increased citrate synthase activity by 20 and 42% in the medial and long heads of the triceps brachii, respectively. Sarcomere lengths were similar in gastrocnemius and soleus muscles of Sed and HIET rats after fixation. All four indexes of capillary supply were significantly greater throughout the gastrocnemius muscle of HIET rats compared with Sed values. The relative increase in capillarity was greater in white than in red gastrocnemius muscle of HIET rats. HIET also increased capillary supply of soleus muscle. However, only capillary numerical density was statistically greater (19%) in HIET soleus compared with Sed. These results support the hypothesis that this training program would produce an increase in capillary supply in all extensor muscles.

Restenosis following placement of an intracoronary heparin treated tantulum stent in the hyperlipidemic miniature swine model.

Restenosis persists as an important factor limiting a favorable long term outcome following mechanical revascularization. The objective of the present study was to compare the effects of an intracoronary heparin treated tantalum prototype stent and balloon angioplasty on intimal hyperplasia, luminal diameter, and thrombosis in a porcine restenosis model. Male miniswine maintained on a high cholesterol diet and 325 mg aspirin per day underwent cardiac catheterization and oversized balloon injury to the right and left circumflex coronary arteries. Two weeks later one artery was either balloon injured again or implanted with a stent. No additional anticoagulation following stent placement was given, however aspirin was continued throughout the study. At four weeks, the coronary arteries were harvested and prepared for histologic examination and blinded quantitative morphometric analysis. The prototype stent was successfully deployed in 10 coronary arteries. Histological examination at explant revealed no evidence for thrombus or platelet aggregation. The angiographic luminal diameter of stented vessels was not significantly different from the diameter measured prior to implantation. In contrast, the angiographic diameter of balloon injured vessels was significantly decreased (4.4 +/- 0.4 mm2, balloon injured, vs. 5.8 +/- 3.3 mm2, control; p < 0.05). Stented arteries showed significantly more intimal hyperplasia, compared to balloon injured vessels (2.99 +/- 0.58 mm2 intimal area, stented arteries vs. 0.38 +/- 0.15 mm2 intimal area, control arteries; p < 0.05). In conclusion, heparin treated tantalum wire prototype intracoronary stents were successfully deployed in swine coronary arteries with no evidence for thrombus formation. Despite a significant intimal response, luminal diameter was preserved in stented vessels. The data suggest that a heparin treated tantalum wire prototype intracoronary stent may be an effective method of coronary revascularization that results in the preservation of luminal diameter without thrombotic occlusion.

Anatomical localization of immunoreactive oxytocin and beta-endorphin in the bovine neurointermediate lobe.

BACKGROUND: Beta-endorphin and oxytocin immunocytochemical localization were examined in the neurointermediate lobe (lobus nervosus and pars intermedia) of the bovine hypophysis in order to describe the anatomical distribution of these two neurointermediate lobe hormones. METHODS: Twenty-seven bovine hypophyses were collected from slaughterhouse animals (seven mature lactating cows, eleven mature nonlactating cows, three nulliparous heifers, and six steers). Hypophyses were immunostained for oxytocin-containing fibers and beta-endorphin-secreting cells by using the avidin biotin-immunoperoxidase method. The distributions of beta-endorphin-positive cells and oxytocin-positive nerve fibers were plotted on projected outlines of the hypophyses. Immunoreactive staining intensity was graded numerically as weak, moderate, or heavy by three individuals who had no knowledge of the animals' physiological status. RESULTS: Oxytocin immunoreactivity was confined to the lobus nervosus while beta-endorphin staining was confined to the pars intermedia and the pars distalis. However, oxytocin immunopositive neurosecretory terminals were distributed more heavily in that part of the lobus nervosus bordering the pars intermedia than in the center of the lobe. CONCLUSIONS: These results were similar to those previously reported for the rat (Swaab et al., 1975; J. Neural Transm., 36:195-215; Deftos and Catherwood, 1980; Life Sci., 27:223-228).

Regional changes in capillary supply in skeletal muscle of interval-sprint and low-intensity, endurance-trained rats.

OBJECTIVE: Exercise training produces regional increases in blood flow capacity among muscle fibers that experience increased activity during exercise. We tested the hypothesis that this increase is partially due to capillary angiogenesis among muscle fibers with large increases in activity during exercise training bouts. METHODS: Two training programs were evaluated: a program consisting of 10-12 weeks of exposure to low-intensity (30 m/min, 0 incline, 60 min/day) (LET) exercise bouts, 5 days/week, and a second program consisting of 8-10 weeks of exposure to repetitive bouts (6/day) of sprint (60 m/min, 15% incline) exercise, alternating running (2.5 min) and recovery (4.5 min), 5 days/week (IST). Cage-confined rats were utilized (SED) as controls. After training was completed, rat hindquarters were perfusion-fixed with modified Karnovsky's fixative. Transverse sections from soleus (Sol), and red (GR), mixed (GM), and white (GW) portions of gastrocnemius muscle were prepared to evaluate capillarization. Sections were analyzed using the Olympus Cue 2 Image Analyzer to determine capillary/muscle fiber ratio (C/F), number of capillary profiles per square millimeter of muscle area (CND), capillary surface area per volume of tissue, and capillary volume density. RESULTS: Average area per muscle fiber and sarcomere length did not differ among groups. LET did not affect capillarization of the GW, whereas increasing C/F in GM (2.3 +/- 0.1 versus 2.1 +/- 0.1 for SED) and GR (3.0 +/- 0.1 versus 2.6 +/- 0.1 for SED). IST increased C/F and CND in GW (1.6 +/- 0.1 versus 1.3 +/- 0.0 for SED and 657 +/- 74 versus 418 +/- 53 for SED, respectively) and increased C/F ratio in GM (2.3 +/- 0.1 versus 2.1 +/- 0.1 for SED). IST did not increase capillarization of the GR. The capillarization of the soleus muscle was not affected by either exercise training program. CONCLUSION: IST increased capillarization in muscle tissue composed of a high percentage of fast glycolytic fibers (GW and GM) and LET increased capillarization of muscle tissue composed of a high percentage of fast oxidative-glycolytic fibers (GW and GR).

Comparison of muscle cell fiber types and oxidative capacity in gracilis, rectus femoris, and triceps brachii muscles in the ferret (Mustela putorius furo) and the domestic dog (Canis familiaris).

Muscle cell fiber types in gracilis, rectus femoris, and long head of triceps brachii muscles of ferrets and dogs were identified on serial sections stained for myosin ATPase after preincubation at pH values of 9.8, 4.6, and 4.3 and for NADH-tetrazolium reductase (NADH-TR) activity. Although fiber types I and II were identified, the ATPase stain did not demonstrate classic type IIA/IIB fiber differences in either species. However, two type II fiber subtypes could be distinguished in the ferret because they differed slightly in staining intensity with ATPase at pH 4.3 and markedly with NADH-TR. One ferret type II fiber (designated II dark or IID) was smaller, slightly darker on ATPase, more oxidative on NADH-TR, and comprised more muscle volume than the other type II fiber (designated II light IIL). The IID fibers of ferret may represent the IID/X fibers of other authors. Both ferret type II fiber subtypes stained darker at pH 4.3 than canine II fibers. The NADH-TR staining indicated high oxidative activity in canine and ferret type I fibers. In contrast, type II fibers in the dog and IIL fibers in the ferret were moderately oxidative. Canine type IIC fibers were intermediate between type I and type II, whereas in the ferret, type IIC fibers were highly oxidative, as were type IID fibers. Ferret muscles are more oxidative than canine muscles according to NADH-TR staining. Also, ferret muscles possess 40-100% higher citrate synthase activity as compared to canine muscles.

Skeletal muscle fiber types and their vascular support.

Different neural and thyroidal influences on mammalian skeletal muscle result in considerable heterogeneity in muscle-fiber characteristics. Muscle fibers can, nonetheless, be grouped into three relatively homogeneous classes, based primarily on their contractile properties. There is a remarkable matching of metabolic support systems to contractile properties and, in turn, appropriate vascular supply for the metabolic systems of each of the three muscle fiber types. The contractile, metabolic, and vascular characteristics of each fiber type are consistent with known patterns of muscle fiber recruitment for the performance of muscular work.

A progesterone-modulated, low-molecular-weight protein from the uterus of the sheep is associated with crystalline inclusion bodies in uterine epithelium and embryonic trophectoderm.

A protein of Mr 14,000 (14K protein) has been identified in the medium after culturing sheep conceptuses in vitro. However, it was also a component of uterine flushes of nonpregnant ewes during the luteal phase of the estrous cycle. The 14K protein, which consists of several isoforms, was purified from conceptus culture medium by a simple three-step procedure, involving ammonium sulfate precipitation, high-performance anion-exchange chromatography, and gel filtration on Sephacryl S-200. Western blotting procedures with an anti-14K antiserum showed that endometrium from ovariectomized ewes began to release the 14K protein after 6 to 14 days of progesterone treatment. Immunostaining of tissue from Day 16 pregnant ewes and from ewes treated with progesterone for 14 or 30 days showed the protein to be confined to the surface and upper glandular epithelium of the endometrium and to be absent from the deep glands. It was also present in trophectoderm of Day 16 conceptuses. Immunogold labeling in conjunction with electron microscopy revealed that within trophectoderm the 14K protein was localized to large, membrane-bound rhomboidal or needle-shaped crystal structures, and it seems likely that the protein was accumulated by the conceptus as a result of uptake of uterine histotroph. In the uterine epithelium, immunogold label was again most strongly concentrated over crystal-like structures but was also uniformly present over the cytoplasm and nucleoplasm. It was absent over mitochondria, over lipid droplets, and over non-epithelial types of endometrial cell. Such a cellular distribution for a secretory protein is novel, and it remains unclear whether the protein is synthesized by these cells.

The anatomy of the visceral and autonomic nervous systems.

The visceral nervous system has several levels of anatomical organization. Individual viscera, including the heart and the intestines, have neural tissue embedded in their walls that is capable, under some circumstances, of a truly autonomic self-regulation of that organ's activity. This self-regulation will not respond to all the varying needs of the organ control, particularly when external or internal changes affect the whole animal. The parasympathetic, sympathetic, and visceral afferent systems and their CNS connections are the next level of reflex neural organization. A greater degree of central regulation is managed at this level. The third level of visceral control is located in the brainstem and includes the hypothalamus, parts of the reticular formation, and cardiorespiratory centers in the medulla. These visceral upper neuron centers exert a high degree of control over the parasympathetic and sympathetic LMN centers of the brainstem and spinal cord. The reticulobulbar and reticulospinal pathways are the means by which the visceral upper motor neurons communicate with the LMN systems. The hypothalamus-hypophyseal system exerts control by releasing hormones to act on distant target organs. The highest level of organization of visceral function takes place in the limbic system. The limbic system is in a position to integrate sensory information originating from both within (interoceptive) and outside (exteroceptive) the animal. Associations are made at this level and with the help of cortical association areas, memory is integrated with these sensations. The limbic system is then able to influence the hypothalamic and medullary centers as well as the somatic motor centers to develop the appropriate responses for the preservation of the animal.

Progesterone induction of the uterine milk proteins: major secretory proteins of sheep endometrium.

Progesterone induction of the uterine milk proteins (UTMP), the major secretory products of the ovine uterus during pregnancy, was studied in ovariectomized ewes given physiological levels of progesterone for 0, 2, 6, 14, or 30 days. Western blotting of uterine flushes and of endometrial explant culture medium, endometrial RNA analyses on dot and Northern blots, and immunocytochemistry performed on uterine tissue sections demonstrated the presence of low levels of UTMP mRNA and UTMP protein after 6 days of progesterone therapy, and increasing levels of UTMP production and secretion after 14 days. Highest activity was observed at Day 30. The induction of the UTMP progressed from small amounts of antigen present in the supranuclear region of a few epithelial cells in deep and middle-depth regions of uterine glands in the Day 6 progesterone-treatment group to large amounts detected in epithelial cells spread throughout the length of the glands in later groups. UTMP production was also identified in the uteri of intact ewes at Day 16 (but not earlier) of the estrous cycle and during early pregnancy (Days 14 to 22). Production of a protein similar to the UTMP was also noted in the uterus of a pregnant cow. The UTMP provide a good model of a progesterone-responsive secretory protein in a mammal whose synthesis is increased gradually over a period of weeks.

Muscle hemodynamics in hereditary myopathy of Labrador retrievers.

Morphologic lesions seen in six 8-month-old Labrador Retrievers with hereditary myopathy were predominantly small- and large-group atrophy of muscle cells of all fiber types. The dogs were intolerant of exercise and fatigued rapidly. An isolated gracilis muscle preparation was used to study the hemodynamic features of the microvasculature. Isogravimetric capillary pressure as well as arterial and venous pressures in the isolated gracilis muscle preparation obtained during maximal vasodilatation were within the range reported for healthy, mixed-breed dogs, as were precapillary, postcapillary, and total vascular resistances. Capillary filtration and osmotic reflection coefficients were not different from those reported in other studies on healthy dogs. All measurements and calculations were repeated during reperfusion, subsequent to a 4-hour period of global ischemia. Postischemic vascular responses were similar to the pattern previously reported in healthy dogs. These studies did not support the hypothesis of a vascular defect as a cause of hereditary myopathy in Labrador Retrievers.

Anury in two Cairn terriers.

Congenital anury (taillessness) was observed in 2 Cairn Terriers. Fecal staining of the hind limbs was evident in both dogs. A mating of the affected dogs produced a litter of 2 apparently normal pups. The small litter size may have been attributable to lethal gene combinations similar to those described in mice. The radiographic appearance of the caudal and sacral vertebrae was atypical in both tailless dogs. Results of myelography and electrodiagnostic testing of anal sphincter function were normal in one of the dogs. One of the tailless dogs was euthanatized and was found to lack specific muscles and muscle parts responsible for normal defecation, which resulted in fecal staining of the hind limbs. Pedigree analysis revealed the tailless dogs to be closely related and slightly inbred, suggesting a hereditary etiologic factor for anury.

Radiation treatment for thymoma in a dog.

A 10-year-old Toy Poodle was admitted for evaluation of a chronic cough caused by a cranial mediastinal mass. The mass was diagnosed, by needle biopsy, as a thymoma. Detection of serum acetylcholine receptor antibodies suggested that the dog had subclinical myasthenia gravis. The dog underwent orthovoltage radiation treatment, which resulted in an approximate 60% reduction in tumor mass and freedom from clinical signs for 6 months. Concurrent use of prednisolone may have been associated with disappearance of the acetylcholine receptor antibodies.

Congenital and acquired neuromuscular disease of young dogs and cats.

Neuromuscular disorders in small animals include a diverse group of congenital and acquired diseases. The prognosis will vary according to the disorder and the portion of the motor unit affected. A number of diseases might be satisfactorily treated (for example, myasthenia gravis, congenital myotonia), whereas others may be self-limiting (for example, hereditary myopathy of Labrador Retrievers). Accurate diagnosis is necessary for establishing a prognosis and treatment plan suitable to the patient and client. Specific diagnosis in the absence of specialized tests is difficult, although not always impossible (for example, congenital myotonia in the Chow Chow). A knowledge of the neuromuscular diseases that might affect small animals, a detailed history, and a thorough physical examination will help in the presumptive diagnosis. Specialized laboratory examinations may need to be applied (for example, antiacetylcholine receptor antibody titer for acquired myasthenia gravis). Referral may be necessary for more detailed diagnostic workup (for example, electromyographic examination, nerve or muscle biopsy examination). In the case of inherited neuromuscular disorders, a knowledge of inheritance patterns will allow genetic counseling to avoid future problem breedings.

Distribution and implications of beta-endorphin and ACTH-immunoreactive cells in the intermediate lobe of the hypophysis in healthy equids.

The distribution of cells that stain positive for beta-endorphin and ACTH immunoreactivity was studied in the pars intermedia (PI) of the hypophysis in 3 healthy horses and 2 healthy ponies. Serial sections treated with commercial antibodies generated against beta-endorphin or ACTH were processed for immunocytochemical studies, using the avidin biotin immunoperoxidase-complex method. Distribution patterns of cells reacting with antibodies were similar in cells from all equids. Cells immunostained for ACTH were numerous and widely distributed in the PI. Cells immunopositive for ACTH probably contain corticotrophin-like intermediate lobe peptide that cross-reacts with antisera to ACTH. Cells immunopositive for beta-endorphin were fewer in number and had a more limited distribution in the PI. Most beta-endorphin-positive cells were located along the border of the PI adjacent to the lobus nervosus and had abundant eosinophilic cytoplasm when stained with hematoxylin and eosin. Cells with prominent eosinophilic cytoplasm were not common in other areas of the PI. When serial sections were examined, cells that stained positive for beta-endorphin immunoreactivity also appeared positive for ACTH.

Muscle lesions in beige (Chediak-Higashi syndrome) and heterozygous C57BL/6J mice.

Muscles from male and female C57BL/6J Chediak-Higashi syndrome (CHS) and phenotypically normal mice with the bgJ allele were studied microscopically and histochemically for the presence of basophilic cytoplasmic structures seen by other investigators in muscles of CHS mice of the SB/Le strain. Triceps brachii, gastrocnemius, quadriceps femoris, and biceps femoris muscles were examined. Multiple basophilic cylindrical lesions were present in hematoxylin and eosin-stained muscle from all groups. Lesions were positive for esterase, Sudan black, and periodic acid-Schiff. Lesions were only seen in type II muscle fibers. Type I muscle cells comprised less than an estimated 5% of the total muscle fibers in the four muscles examined. Scores were assigned based on the presence or absence of lesions in each muscle. Male mice of both phenotypes had significantly more lesions (P less than 0.05) than female mice. When sexes were combined, lesions were significantly (P less than 0.05) more numerous in normal mice than CHS mice for all muscles except the gastrocnemius. Lesions were significantly (P less than 0.05) more numerous in the phenotypically normal male than the CHS male mice for the triceps and quadriceps muscles. There was no significant difference (P greater than 0.05) between lesions of phenotypically normal female and female CHS mice. Basophilic cytoplasmic structures did not prove to be a manifestation of the CHS trait.