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PubMed1975

[Electron microscope study of spermatogenesis in two cestodes acanthobothrium filicolle benedenii Loennberg, 1889 and Onchobothrium uncinatum (Rud., 1819) (Tetraphyllidea, Onchobothriidae) (author's transl)].

The spermatogenesis, spermatozoon differentiation and fine structure of Acanthobothrium filicolle benedenii Loennberg, 1889 and Onchobothrium uncinatum (Rud., 1819) were studied by means of light and electron microscopy. Spermatogenesis in both species is of the rosette type. During sperm differentiation, the five following stages have been distinguished: (1) formation of arching membranes and differentiation zone; (2) nuclear elongation; (3) formation of two flagella with a median cytoplasmic process; (4) flagellar rotation; (5) fusion of two flagella with the median cytoplasmic process induced by the migration of nucleus into the latter. The mature spermatozoa of both species are threadlike structures about 250 mum long. They consist of two axonemes of the platyhelminth type (9+1 pattern), elongated nucleus and cortical microtubules embedded in a cytoplasmic matrix containing numerus beta-glycogen particles. The body which appears on cross-sections as crest, lateral with respect to the axoneme, is present in both species. Such a body is reported for the first time in Cestode spermatozoa. There is no mitochondrion in the two Onchobothriidae sperms studied.

Animals↗
PubMed1978

Cathodoluminescence applied to immunofluorenscence: present state and improved technical prospects by prism spectrometer light selection.

For studies on cathodoluminescence, we equipped a scanning electron microscope with a prism spectrometer and sensitive photomultiplier. The apparatus is described and our initial results are presented on the analyse of cathodoluminescence. The material observed promarily involved studies of immunofluorescent specimens. Humal lymphocytes were labelled with a fluorescent antibody and cryosections of rat kidney with Masugi nephritis were labelled with a fluorescent specific antibody. Our apparatus permitted monochromatic imaging of cathodoluminescence emissions and resulted in much improved micrographs. Some possible improvements of the technique are discussed.

Animals↗
PubMed1976

Ultrastructure of the Gunn rat substantia nigra. II. Mitochondrial changes.

The substantia nigra of hyperbilirubinemic (Gunn) rats was studied using light and electron microscopic techniques. PAS-positive inclusions were observed within the neuronal somata of animals 2 to 12 weeks old. Incubation of tissue sections in 0.5% diastase inhibited most of the positive PAS reaction, thus indicating the intraneuronal presence of glycogen. Electron microscopic examination of the tissue substantiated the histochemical data. Mitochondria in neuronal somata contained collections of osmiophilic granules, 200-300 A diameter, in their intracristal (intermembrane) space. These granules were typical of beta-glycogen particles. In increasingly older animals (from 2 to 12 weeks old) progressively fewer collections of intramitochondrial glycogen were observed. In these same animals there was, however, a concomitant increase of osmiophilic granules, 400-600 A diameter, located in the cisternae of granular endoplasmic reticulum. These granules corresponded to alpha-glycogen. After 12 weeks of age, only occasional glycogen granules were seen in either the mitochondria or endoplasmic reticulum. It is suggested that the intramitochondrial glycogen represents an alternate means by which the neuron is able to manufacture ATP following the disruption of oxydative phosphorylation caused by bilirubin. Furthermore it is suggested that with the recovery of oxydative phosphorylation the intramitochondrial collections of glycogen are transferred to the endoplasmic reticulum where glycogenolysis might possibly occur.

Age Factors↗
PubMed1993

Ultrastructural study of the spermatogenesis and mature spermatozoa of Dicrocoelium dendriticum (Plathelminthes, Digenea).

The spermatogenesis and spermatozoon of Dicrocoelium dendriticum were studied by transmission electron microscopy. Peripheric accessory cells project between germ cells. Each spermatogonium gives rise to 32 spermatozoa. The stages in spermiogenesis include development of the zone of differentiation, appearance of the intercentriolar body flanked by two centrioles from each of which a free axoneme and a striated rootlet grow, outgrowth of the differentiation zone to form the median cytoplasmic process and migration of the nucleus and mitochondria into it, and rotation of the flagella and subsequent proximodistal fusion of the three projections to form a monopartite spermatozoon. The spermatozoon possess two incorporated axonemes with the "9 + 1" pattern typical of those in trepaxonematid plathelminths. beta-Glycogen particles accumulate in the spermatozoa after they have separated from the cytophore as revealed by Thiery's method. This study confirms in a further family, Dicrocoeliidae, the constant pattern of spermiogenesis and spermatozoon structure in Digenea.

Animals↗
PubMed1984

Experimental evidence for beta-decay as a source of chirality by enantiomer analysis.

Earlier experiments testing the Vester-Ulbricht beta-decay hypothesis for the origin of molecular chirality are reviewed, followed by descriptions of our own experiments involving attempted asymmetric radiolysis of DL-amino acids using quantitative gas chromotography as a probe for optical activity. Our radiation sources included 90Sr-90Y, 14C and 32P Bremsstrahlen, longitudinally polarized electrons from a linear accelerator and longitudinally polarized protons from a cyclotron. With the possible exception of the linear accelerator irradiations, these experiments failed to produce g.c.-detectable enantiomeric excesses, even at 50-70% gross radiolysis. We thus find no unambiguous support for the Vester-Ulbricht hypothesis in any of the attempted asymmetric radiolyses performed to date. Radioracemization, a possible reason for these failures, is discussed.

Amino Acids↗
PubMed1986

DNA repair kinetics after exposure to X-irradiation and to internal beta-rays in CHO cells.

DNA strand breaks induced by X- or internal beta-rays were measured using the alkaline unwinding technique. For either type of radiation, repair kinetics were found to be best described by three exponential components, the half-times of which are 2 min, 17 min and 200 min, respectively. These values are the same for X- and internal, beta-irradiation but the initial fractions of the components are different.

Animals↗
PubMed1982

hard tissue biochemistry: a comparison of fresh-frozen and formalin-fixed tissue samples.

Formalin fixation of hard tissues alters the levels of some, but not all, of the parameters routinely measured by bone researchers. Although mineral parameters (ash weight, particle size (beta 1/2 002) and Ca/PO4 ratio) and lipid parameters (total lipid content and composition, extractability, and Ca-acidic phospholipid phosphate content) are not affected by formalin fixation, the uronate and DNA contents are reduced in formalin-fixed bone while hydroxyproline content is elevated.

Bone and Bones↗
PubMed1998

Intraarterial beta irradiation to reduce restenosis after PTCA. Experimental and clinical experience.

The present data demonstrate clinical feasibility of intracoronary beta brachytherapy and fail to reveal any complications that could be attributed to it. Definitive conclusions regarding safety will have to await longer term evaluation. Proof of efficacy will require strict dose finding evaluation of higher doses than those used in the present pilot study followed by a controlled, randomized trial using both clinical and angiographic end-points.

Aged↗
PubMed1998

Efficacy of beta radiation in prevention of post-angioplasty restenosis. An interim report from the beta energy restenosis trial.

UNLABELLED: Restenosis remains a major limitation of coronary angioplasty in spite of major advances in techniques and technology. Recent studies have demonstrated that ionizing radiation may limit the degree of this problem. Gamma radiation has been shown to be effective in reducing in stent restenosis in humans, and beta radiation following encouraging results in animals has been shown to be feasible in humans. The objective of this study was to assess the feasibility of a 5 F non-centered catheter to deliver beta radiation emitting seeds to the lesion site post angioplasty and its effect on restenosis. Following successful angioplasty, patients were randomized to treatment with 12, 14 or 16 Gy at the angioplasty site. This was delivered with a 5 F non-centered catheter. Twelve beta radiation emitting seeds (90Sr/Y) were delivered to an area 3 cm in length to cover the angioplasty site. Angiographic follow-up was performed at 6 months. Baseline and follow-up angiograms were performed by blinded investigators at a core laboratory. This interim report comprises the first 35 patients to complete 6-month angiographic follow-up. There were no major radiation incidents. Four patients had evidence of angiographic restenosis. The MLD (mm) and percent stenosis were 0.77 +/- 0.27/72.5 +/- 8.6 pre angioplasty, 2.08 +/- 0.4/25.7 +/- 9.8 post angioplasty and radiation and 2.05 +/- 0.59/25.7 +/- 19.8 at follow-up respectively. CONCLUSION: Beta radiation can be feasibly and safely delivered post coronary angioplasty with a very encouraging reduction of restenosis.

Adult↗
PubMed1998

Intracoronary radiation using radioisotope solution-filled balloons.

A substantial body of experimental evidence suggests that local application of radiation at sites of angioplasty or stent implantation prevents neointima formation. Recent initial clinical studies report a significant reduction in clinical restenosis rates when gamma emitting radiation sources are used to treat the site of coronary intervention. Because of the energy of therapeutic gamma sources and the shielding requirements, it would be far preferable to deliver ionizing radiation using a local beta emitter. This report discusses a number of the physical, biological, and technical parameters involved in radiation from a balloon angioplasty catheter filled with a beta emitting radioisotope solution.

Angioplasty, Balloon, Coronary↗
PubMed2004

Use of water-equivalent plastic scintillator for intravascular brachytherapy dosimetry.

Beta irradiation has recently been investigated as a possible technique for the prevention of restenosis in intravascular brachytherapy after balloon dilatation or stent implantation. Present methods of beta radiation dosimetry are primarily conducted using radiochromic film. These film dosimeters exhibit limited sensitivity and their characteristics differ from those of tissue, therefore the dose measurement readings require correction factors to be applied. In this work a novel, mini-size (2 mm diameter by 5 mm long) dosimeter element fabricated from Organic Plastic Scintillator (OPS) material was employed. Scintillation photon detection is accomplished using a precision photodiode and innovative signal amplification and processing techniques, rather than traditional photomultiplier tube methods. A significant improvement in signal to noise ratio, dynamic range and stability is achieved using this set-up. In addition, use of the non-saturating organic plastic scintillator material as the detector enables the dosimeter to measure beta radiation at very close distances to the source. In this work the plastic scintillators have been used to measure beta radiation dose at distances of less than 1 mm from an Sr-90 cardiovascular brachytherapy source having an activity of about 2.1 GBq beta radiation levels for both depth-distance and longitudinal profile of the source pellet chain, both in air and in liquid water, are measured using this system. The data obtained is compared with results from Monte Carlo simulation technique (MCNP 4B). Plastic scintillator dosimeter elements, when used in conjunction with photodiode detectors may prove to be useful dosimeters for cardiovascular brachytherapy beta sources, or other applications where precise near-source field dosimetry is required. The system described is particularly useful where measurement of actual dose rate in real time, a high level of stability and repeatability, portability, and immediate access to results are prime requirements.

Beta Particles↗
PubMed2002

[Intracoronary radiation therapy in controlled and open clinical trials with afterloading systems and "hot" balloon catheters. Analysis of 6,692 patients].

The prevention and treatment of a restenosis, which occurs in ca. 30% of the cases following balloon dilatation of coronary stenoses, using intravascular radiation relies on the inhibition of proliferation that is inherent in every radiation therapy. The analysis is based on 6,692 patients assigned to either a control group (1,717 patients) or to radiation therapy (4,975 patients) in 41 studies. A total of 14 placebo-controlled, randomized and 27 open trials have been completed: 22 regarding in-stent restenosis, ten regarding de-novo stenosis (or restenosis without a stent) as strict inclusion criteria, and nine with all types of stenoses. For in-stent restenoses, vessel size as defined for inclusion was between 2.0 mm and 5.5 mm, stenosis length between 10 mm and 80 mm. In all trials with in-stent restenosis, the primary endpoints were reached; the restenosis rate in the longest coronary segment analyzed was between 45% and 100% in the control groups and between 7.7% and 53.5% in the brachytherapy groups. The respective values for the TVR were between 24.1% and 80% in the control groups and between 2.0% and 41.7% in the brachytherapy groups. In the control groups, MACE was between 25.9% and 80%; it was between 2.0% and 41.7% in the brachytherapy groups. Attaining results for de-novo stenoses was problematic due to "geographic miss" apparently playing a larger role in these cases; but when taking this into consideration, good results were also attained. The known limitations due to late stent thromboses (4-15% in older trials) were to the most part eliminated by administration of clopidogrel for 1 year and the limitations due to the "edge effect" by the application of longer radiation sources. With antiproliferative coated stents as treatment for de-novo stenoses, we can count on intracoronary brachytherapy losing significance in this area. But for in-stent restenoses, intracoronary brachytherapy is the only evidence-based interventional form of therapy.

Aged↗
PubMed2006

Postoperative irradiation for pterygium: retrospective analysis of 1,253 patients from the Osaka University Hospital.

BACKGROUND AND PURPOSE: Irradiation of ocular pterygium is considered a valuable treatment supplementation after surgical therapy. Since prospective randomized trials are scare and only limited patient data are available, the aim of this study was to evaluate the patient population treated with fractioned 90Sr irradiation after surgical pterygium resection. PATIENTS AND METHODS: Between September 1993 and March 2001, 1,147 patients with pterygium lesions (1,320 lesions) were treated surgically and with 90Sr postoperative beta-irradiation. A total dose of 30 Gy was used for patients treated within 48 h after surgery, while those treated>48 h postoperatively received a total dose of 35 Gy. A minimum follow-up period of 3 months was required for inclusion in the analysis, and 1,253 lesions were ultimately analyzed. RESULTS: Recurrence of the pterygium after postoperative 90Sr irradiation was observed in 97 of 1,253 cases (7.7%). Statistical analysis (uni- and multivariate) revealed, that male gender, younger age (<40 years), prior treatment (surgery and radiotherapy) and immediate irradiation (<2 h after surgery) were negative predictors for local recurrence. Temporary radiotherapy-induced side effects were observed in 15.2% of patients, including moderate conjunctivitis, local pain, visual disturbance and photophobia or an increase in tear flow. However, no long-term serious side effects were documented. CONCLUSION: 90Sr irradiation of pterygium after surgery represents a safe and effective treatment option to prevent disease recurrence. The data obtained in this study indicate that a certain interval after surgery might improve therapy outcome.

Adult↗