Ultrastructural Study of the Nuclei in Premitotic and Repair DNA Synthesis Following UVB Injury

Ultrastructural changes in nuclei synthesizing DNA were studied by cytochemical technique. Guinea pig ears were UVB irradiated and TdR-H3 was injected intradermally into the irradiated sites 1 hr before biopsy. Areas of the epidermis containing more than 80% of cells in DNA (repair or premitotic) synthesis identified by light microscopic autoradiography were selected and cut at 600 Å. The glycolmethacrylate sections were stained with uranyl acetate and lead citrate, and consecutive sections were incubated with 0.01% pronase and 0.5% RNase before staining in order to observe DNA. In cells undergoing DNA repair, the zone of DNA became discontinuous and DNA was scattered throughout the entire karyoplasm as small aggregates and fine filaments. Nuclei in S-phase showed essentially the same change, but quantitatively the disappearance of DNA from the nuclear membrane and distribution in the karyoplasm became much greater. These changes were not seen in specimens treated without cytochemical technique

Autotransplantation of Hepatic Granulomas into the Skin of Mice with Schistosoma mansoni Infection

Hepatic egg granulomas of mice infected with Schistosoma mansoni were transplanted into the skin of the same animal and changes occurring to macrophages, eosinophils, and mast cells over time were studied by light and electron microscopy and by autoradiographic techniques. Disappearance of cellular components about the egg granulomas occurred within 1week; the entire implant became encapsulated by inflammatory cells and stroma. By 3weeks monomuclear cells and macrophages reorganized the granulomas around the eggs and neutrophils disappeared. Activated macrophages contained both secretory rough endoplasmic reticulum and lysosomal-dense bodies. Granuloma size increased up to 5weeks after implantation and mast cells and cosinophils tended to migrate into the granulomas. The mast cell index always remained lower than in the original hepatic granulomas, while eosinophils were seen in large numbers. During 3 to 8weeks after implantation mononuclear cells undergoing DNA synthesis in the granulomas ranged from 2.9–4.8%. Some 3-week-old autotransplants were injected with 3H-thymidine and biopsied from 1 to 21days later. Labeled mononuclear cells peaked in the granulomas by 10days (24%) and the numbers fell off sharply after that.These findings indicate that autologously implanted schistosome egg granulomas can be maintained successfully in the skin for prolonged periods with marked ingress of macrophages and eosinophils. The autoradiographic data suggest lesions are high turnover granulomas

Detection a Fibrous Component in Keratohyalin Granules of Newborn Rat Epidermis

Keratohyalin granules of frozen newborn rat epidermis were stained histologically and immunohistochemically and studied by light and electron microscopy. They showed a variety of reactivity to eosin, hematoxylin, uranyl acetate and rabbit monospecific antikeratin IgG. We found that good preservation of ultrastructure can be obtained from quickly frozen skin, and filamentous components remain after extraction of tissue substances by 0.14 m NaCl in 0.1 m-Tris-HCl buffer, pH 8.0. Furthermore, filaments in keratohyalin granules became immunologically reactive with rabbit anti-keratin IgG after extraction. Poststain with uranyl acetate further facilitated ultrastructural demonstration of filaments in the granules. These results indicate that filaments are one of the constituents of keratohyalin granules and the staining property changes occur in tonofilaments as they associate with other components to form keratohyalin granules

Eosinophil Response in Guinea Pig Skin to a Low Molecular Weight Eosinophil Chemotactic Factor Extracted from Livers of Mice with Schistosomiasis

A low-molecular weight eosinophil chemotactic factor (ECF-G), isolated and partially purified from livers of mice with schistosomiasis, was injected intradermally into guinea pigs. Biopsies obtained were studied for inflammatory cell accumulation in the injected sites and compared with those in the control sites injected with phosphate buffered saline. Tissue eosinophilia was seen as early as 1hr after injection of ECF-G, but not in the control site. The increase of eosinophilia appeared biphasic with peaks at 6 and 24hr. Mast cells increased in both ECF-G and saline injected sites and the increase was still found at 120hr after injection. Neutrophils also increased in both ECF-G and saline injected sites but disappeared within 48hr.These findings indicate that ECF-G is a tissue and species nonspecific eosinophil chemotactic factor, and injection of ECF-G initiates interaction of eosinophils and mast cells in the skin

In Vitro Demonstration of Delayed Hypersensitivity in Patients with Berylliosis

To clarify immunopathological mechanisms in granulomatous hypersensitivity (GHR) to beryllium (Be), migration inhibitory factor (MIF) was assayed. Blood lymphocytes from three patients with GHR to Be and two normal persons were isolated and cultured with and without BeO or other antigens. Cell-free supernatants removed daily were dialyzed, lyophilized and assayed for MIF by measuring the area of migration of normal guinea pig peritoneal exudate cells out of capillary tubes within 24 hours after exposure to the supernatant. BeO added to sensitized lymphocytes produced supernatant that decreased migration, in contrast to supernatant from non-sensitized lymphocytes, indicating that BeO-sensitized lymphocytes cultured with Be elaborate a soluble factor, MIF, which correlates with delayed hypersensitivity and may play a role in granuloma formation. It may also prove useful in diagnosis of berylliosis

The Orbiter Stability Experiment on STS-40

The Orbiter Stability Experiment (OSE) was developed to evaluate the steadiness of the STS Orbiter as a potential platform for instrumentation that would image the Sun in its extreme ultraviolet and soft X-ray radiations. We were interested in any high frequency motions of the Orbiter's orientation due to normal operations and manned activities. Preliminary results are presented of the observations. Other than the expected slow motion of the Orbiter within the specified angular deadband of 0.1 degrees during the observations, it was found that high frequency (above 1 Hz) angular motions (jitter) were not detectable at the 0.25 arc sec detection limit of the most sensitive detector, for most of the period of observation. No high frequency motions were recorded during intervals that were identified with vernier thruster firings. However, one short interval with detectable spectral power to a frequency of 10 Hz has been found to date. It has not yet been correlated with a particular activity going on at the time. The results of the observations may also be of value in assessing perturbations to the Orbiter's micro-gravity environment produced by normal operations

Intermediate septal accessory pathways: Electrocardiographic characteristics, electrophysiologic observations and their surgical implications

AbstractIntermediate septal accessory pathways are located in close proximity to the atrioventricular (AV) node and His bundle, have unique features that distinguish them from typical anterior and posterior accessory pathways and have been associated with a high risk for unsuccessful pathway division and the production of complete AV block after surgery. Between July 1986 and May 1990, 4 of 70 patients (3 men and 1 woman; mean age 33 ± 13 years) undergoing surgery for accessory pathway division were found to have an intermediate septal accessory pathway. The presenting arrhythmia was atrial fibrillation with rapid anterograde conduction over the accessory pathway in two patients and recurrent orthodromic reciprocating tachycardia in two patients.In all patients, the delta wave on the electrocardiogram (ECG) was inversed in lead V1, but two patterns of delta wave configuration were observed. In three patients (type 1 intermediate septal accessory pathway), the delta wave was upright in lead II, inverted in lead III and isoelectric in lead aVF; the transition from a negative to an upright delta wave occurred in lead V2. The fourth patient exhibited a different delta wave pattern (type 2 intermediate septal accessory pathway). The delta wave was upright in each of leads II, III and aVF; the transition from a negative to an upright delta wave occurred at lead V3.Intraoperative electrophysiologic study localized the atrial insertion of type 1 pathways to the midpoint of Koch's triangle close to the AV node. In the one patient with a type 1 pathway in which both anterograde and retrograde accessory pathway conduction was present, preoperative catheter mapping demonstrated that earliest retrograde atrial activation occurred near the foramen ovale. Intraoperative mapping during anterograde conduction over the type 1 pathway demonstrated earliest epicardial ventricular activation to occur simultaneously at the crux and the base of the aorta. The atrial insertion of the type 2 intermediate septal accessory pathway was localized to the apex of Koch's triangle in close proximity to the bundle of His. Preoperative catheter mapping revealed that earliest retrograde atrial activation occurred on the His bundle electrogram. Intraoperative mapping during anterograde conduction over the type 2 pathway demonstrated that earliest epicardial ventricular activation occurred anteriorly at the base of the aorta.Intraoperative ablation of the intermediate septal accessory pathway was accomplished by cooling the endocardium at the site of pathway insertion on the atrial side of the tricuspid anulus with a 5 mm cryoprobe. Patients with a type 1 intermediate septal accessory pathway had preservation of AV conduction, but the patient with the type 2 pathway did not and required permanent pacing. At late follow-up study, no patient has had return of intermediate septal accessory pathway conduction. Distinguishing an intermediate septal accessory pathway close to the AV node (type 1) from one close to the His bundle (type 2) is useful to predict both surgical success and success without the production of permanent complete AV block