The Initial Formation and Subsequent Development of the Double Visual Cells in Amphibia

Development ◽  
1956 ◽  
Vol 4 (1) ◽  
pp. 57-65
Author(s):  
Lauri Saxén
Keyword(s):  
Subsequent Development ◽  
Sufficient Evidence ◽  
Considerable Proportion ◽  
Visual Cell ◽  
Structure Development ◽  
Initial Formation ◽  
Visual Cells ◽  
Rods And Cones ◽  
One Year ◽  
And Function

In 1867 Schultze described the main types of visual cell in the vertebrates, the rod and the cone, and one year later a third type, the double cone. The two first-mentioned types have subsequently been the objects of a large number of investigations; hence their structure, development, and function are largely understood. On the other hand, the double cells have attracted surprisingly little interest. Many writers apparently do not know of their existence, whilst others mention them only as a rarity, not deserving of particular study. Physiologists, too, speak only of rods and cones, without crediting the double cells with any specific function. The very fact, however, that double cells are extremely common in the vertebrates and compose, as a rule, a considerable proportion of the retinal receptors, should be sufficient evidence that they are not an insignificant rarity, and still less artefacts, as has sometimes been alleged.

scholarly journals RENEWAL OF GLYCEROL IN THE VISUAL CELLS AND PIGMENT EPITHELIUM OF THE FROG RETINA

1974 ◽  
Vol 62 (2) ◽  
pp. 378-389 ◽  
Author(s):  
Carol Bibb ◽  
Richard W. Young
Keyword(s):  
Pigment Epithelium ◽  
Lipid Synthesis ◽  
Plexiform Layer ◽  
Visual Cell ◽  
Oil Droplets ◽  
Visual Cells ◽  
Rods And Cones ◽  
Outer Segments ◽  
Frog Retina ◽  
Autoradiographic Analysis

The renewal of glycerol in the visual cells and pigment epithelium of the frog retina was studied by autoradiographic analysis of animals injected with [2-3H]glycerol. Assay of chloroform:methanol extracts showed that the labeled precursor was used mainly in lipid synthesis, although there was also some utilization in the formation of protein. Radioactive glycerol was initially concentrated in the myoid portion of rods and cones, indicating that this is the site of phospholipid synthesis in visual cells. The glycogen bodies (paraboloids) of accessory cones were also heavily labeled, suggesting the diversion of some glycerol into glycogenic pathways. In the pigment epithelium, only the oil droplets became significantly radioactive. The outer plexiform layer (which contains the visual cell synaptic bodies) and the cone oil droplets gradually accumulated considerable amounts of labeled material. Within 1–4 h, labeled molecules began to appear in the visual cell outer segments, evidently having been transported there from the myoid portion of the inner segment. Most of these were phospholipid molecules which became distributed throughout the outer segments, presumably replacing comparable constituents in existing membranes. In rods only, there was also an aggregation of labeled material at the base of the outer segment due to membrane biogenesis. These highly radioactive membranes, containing labeled molecules of lipid and protein, were subsequently displaced along the rod outer segments due to repeated membrane assembly at the base. The distribution of radioactivity supported the conclusion that membrane renewal by molecular replacement is more rapid for lipid than it is for protein.

scholarly journals PROTEIN SYNTHESIS IN THE VISUAL CELLS OF THE HONEYBEE DRONE AS STUDIED WITH ELECTRON MICROSCOPE RADIOAUTOGRAPHY

1972 ◽  
Vol 55 (3) ◽  
pp. 595-605 ◽  
Author(s):  
Alain Perrelet
Keyword(s):  
Protein Synthesis ◽  
Electron Microscope ◽  
Single Injection ◽  
Visual Cell ◽  
Maximal Concentration ◽  
Cell Region ◽  
Photoreceptor Membrane ◽  
Visual Cells ◽  
Rods And Cones ◽  
Honeybee Drone

Protein synthesis was studied in the visual cells of an insect (honeybee drone, Apis mellifera) by electron microscope radioautography. After a single injection of tritiated leucine, the radioactivity first appears in the cytoplasm of the visual cell which contains ribosomes. Later, part of this radioactivity migrates to the rhabdome, the visual cell region which is specialized in light absorption. A maximal concentration of radioactivity is reached there 48 hr after the injection of leucine. This pattern of protein synthesis and transport resembles that described in vertebrate visual cells (rods and cones), where newly synthesized proteins have been shown to contribute to the renewal of the photoreceptor membrane.

Osseointegration interface of calcified bone and endosseous implants

1992 ◽  
Vol 50 (2) ◽  
pp. 1096-1097
Author(s):  
K.E. Krizan ◽  
J.E. Laffoon ◽  
M.J. Buckley
Keyword(s):  
Structure And Function ◽  
Titanium Implants ◽  
En Bloc ◽  
Endosseous Implants ◽  
Ultrastructural Studies ◽  
The Past ◽  
Cacodylate Buffer ◽  
One Year ◽  
And Function

With increase use of tissue-integrated prostheses in recent years it is a goal to understand what is happening at the interface between haversion bone and bulk metal. This study uses electron microscopy (EM) techniques to establish parameters for osseointegration (structure and function between bone and nonload-carrying implants) in an animal model. In the past the interface has been evaluated extensively with light microscopy methods. Today researchers are using the EM for ultrastructural studies of the bone tissue and implant responses to an in vivo environment. Under general anesthesia nine adult mongrel dogs received three Brånemark (Nobelpharma) 3.75 × 7 mm titanium implants surgical placed in their left zygomatic arch. After a one year healing period the animals were injected with a routine bone marker (oxytetracycline), euthanized and perfused via aortic cannulation with 3% glutaraldehyde in 0.1M cacodylate buffer pH 7.2. Implants were retrieved en bloc, harvest radiographs made (Fig. 1), and routinely embedded in plastic. Tissue and implants were cut into 300 micron thick wafers, longitudinally to the implant with an Isomet saw and diamond wafering blade [Beuhler] until the center of the implant was reached.

scholarly journals A Mental Health Drop-In Centre Offering Brief Transdiagnostic Psychological Assessment and Treatment in a Paediatric Hospital Setting: A One-Year Descriptive Study

2021 ◽  
Vol 18 (10) ◽  
pp. 5369
Author(s):  
Matteo Catanzano ◽  
Sophie D Bennett ◽  
Marc S Tibber ◽  
Anna E Coughtrey ◽  
Holan Liang ◽  
...  
Keyword(s):  
Mental Health ◽  
Young People ◽  
Psychological Assessment ◽  
Mental Health Problems ◽  
Hospital Setting ◽  
Considerable Proportion ◽  
Paediatric Hospital ◽  
Cognitive Behaviour ◽  
Assessment And Treatment ◽  
One Year

Aim: This study was part of a broader project to examine the acceptability, feasibility and impact of a transdiagnostic mental health drop-in centre offering brief psychological assessment and treatment for children and young people and/or their families with mental health needs in the context of long-term physical health conditions (LTCs). The aims of this investigation were to characterise: (i) the use of such a centre, (ii) the demographics and symptoms of those presenting to the centre, and (iii) the types of support that are requested and/or indicated. Methods: A mental health “booth” was located in reception of a national paediatric hospital over one year. Characteristics of young people with LTCs and their siblings/parents attending the booth were defined. Emotional/behavioural symptoms were measured using standardised questionnaires including the Strengths and Difficulties Questionnaire (SDQ). Participants subsequently received one of four categories of intervention: brief transdiagnostic cognitive behaviour therapy (CBT), referral to other services, neurodevelopmental assessment or signposting to resources. Results: One hundred and twenty-eight participants were recruited. The mean age of young people was 9.14 years (standard deviation: 4.28); 61% identified as white and 45% were male. Over half of young people recruited scored in the clinical range with respect to the SDQ. Presenting problems included: anxiety (49%), challenging behaviour (35%), low mood (22%) and other (15%). Conclusions: A considerable proportion of young people with LTC in a paediatric hospital scored in the clinical range for common mental health problems, indicating a potential for psychological interventions.

scholarly journals HIV Protease: Historical Perspective and Current Research

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 839
Author(s):  
Irene T. Weber ◽  
Yuan-Fang Wang ◽  
Robert W. Harrison
Keyword(s):  
Molecular Mechanisms ◽  
Subsequent Development ◽  
Historical Background ◽  
Hiv Protease ◽  
Drug Resistant ◽  
Immunodeficiency Virus ◽  
Evolution Of Resistance ◽  
Retroviral Proteases ◽  
And Function ◽  
Retroviral Protease

The retroviral protease of human immunodeficiency virus (HIV) is an excellent target for antiviral inhibitors for treating HIV/AIDS. Despite the efficacy of therapy, current efforts to control the disease are undermined by the growing threat posed by drug resistance. This review covers the historical background of studies on the structure and function of HIV protease, the subsequent development of antiviral inhibitors, and recent studies on drug-resistant protease variants. We highlight the important contributions of Dr. Stephen Oroszlan to fundamental knowledge about the function of the HIV protease and other retroviral proteases. These studies, along with those of his colleagues, laid the foundations for the design of clinical inhibitors of HIV protease. The drug-resistant protease variants also provide an excellent model for investigating the molecular mechanisms and evolution of resistance.

One-year follow-up of myocardial perfusion and function evaluated by gated SPECT MIBI in patients with earlier myocardial infarction and chronic total occlusion

2009 ◽  
Vol 30 (1) ◽  
pp. 68-75 ◽  
Author(s):  
Smiljana V. Pavlovic ◽  
Dragana P. Sobic-Saranovic ◽  
Branko D. Beleslin ◽  
Miodrag C. Ostojic ◽  
Milan A. Nedeljkovic ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Myocardial Perfusion ◽  
Chronic Total Occlusion ◽  
Gated Spect ◽  
Total Occlusion ◽  
One Year ◽  
And Function

scholarly journals 701. Blood Stream Infection And Risk Of Endocarditis Following Cardiac Valve Repair: A Population-Based Study

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S401-S401
Author(s):  
Jack McHugh ◽  
Talha Khawaja ◽  
Larry M Baddour ◽  
Larry M Baddour ◽  
Juan Crestanello ◽  
...  
Keyword(s):  
Risk Factors ◽  
Blood Stream Infection ◽  
Subsequent Development ◽  
Bloodstream Infections ◽  
Population Based ◽  
Cardiac Valve ◽  
Valve Repair ◽  
Population Based Study ◽  
Increased Risk ◽  
One Year

Abstract Background Bloodstream infections (BSIs) confer an increased risk of infective endocarditis (IE) in patients with a prosthetic cardiac valve. This relationship is less well established in patients undergoing valve repair. We conducted a retrospective population-based study to determine the incidence of BSIs following valve repair and identify risk factors associated with the development of IE. Methods The Rochester Epidemiology Project (REP) data linkage system was used to identify all persons who underwent valve repair in a 7-county region in Southeastern Minnesota between January 1, 2010 and December 31, 2018. Medical records were screened for the development of a BSI from time of procedure until May 15, 2020. Patients were classified as having BSI only, BSI with IE at outset, or BSI with subsequent development of new IE. IE at outset was defined as cases where IE was diagnosed at the time of initial positive blood culture. Results A total of 387 patients underwent valve repair surgery. A total of 31 (8%) patients subsequently developed a BSI, 4% within one year of surgery. Seventeen patients underwent mitral repair with annuloplasty, 9 underwent tricuspid annuloplasty, and 5 had concurrent repairs. Median time to the development of BSI was 338 days. Of the 31 patients with BSI, 4 (13%) had BSI with IE at outset. No patients developed IE subsequent to BSI, Enterococcus spp. was responsible for 3 cases of IE, and MSSA for 1. All cases occurred within one year of surgery. Given the low incidence, statistical analysis of associated risk factors for IE was not feasible. All patients with BSI and IE at outset, however, died by the end of the study period, versus 11/27 in the BSI only group. Conclusion Incidence of BSIs was higher in patients undergoing cardiac valve repair than in the general population. The incidence of IE with a BSI was 13%, which is lower than what has been previously published. It is notable that all cases of IE occurred within one year of surgery. Recognizing that endothelialization of device surfaces occurs, it is tempting to speculate that the risk of IE may be time dependent and may decline over time. Subsequent investigation of this theory is underway. Disclosures Larry M. Baddour, MD, Boston Scientific (Consultant)

scholarly journals Treatment of head and neck cancer with photodynamic therapy: results after one year

1995 ◽  
Vol 109 (11) ◽  
pp. 1072-1076 ◽  
Author(s):  
M. G. Dtlkes ◽  
M. L. DeJode ◽  
Q. Gardiner ◽  
G. S. Kenyon ◽  
P. McKelvie
Keyword(s):  
Head And Neck Cancer ◽  
Photodynamic Therapy ◽  
Head And Neck ◽  
Neck Cancer ◽  
First Generation ◽  
Sufficient Evidence ◽  
Clinical Responses ◽  
Promising Treatment ◽  
One Year ◽  
Multicentre Prospective Study

AbstractPhotodynamic therapy (PDT) is a new and promising treatment modality for the treatment of malignant disease. This paper reports the preliminary experience of our group in the use of this therapy for the treatment of tumours arising in the head and neck. The majority of treatments in these cases have used a second generation systemic photosensitizer, meta-tetrahydroxyphenylchlorin (m-THPC). Two other cases were treated with either Photofrin 2 (a first generation systemic sensitizer) or with the topical photosensitizer, delta-aminolaevulinic acid (δ-ALA).The initial results have been encouraging with good clinical responses evident in patients presenting with a variety of differing tumour types. We feel there is now sufficient evidence of the efficacy of this treatment to warrant a multicentre prospective study into the treatment of early head and neck cancer with PDT.

The Question of Relationship Between Golgi Vesicles and Synaptic Vesicles in Octopus Neurons

1970 ◽  
Vol 7 (1) ◽  
pp. 189-201
Author(s):  
E. G. GRAY
Keyword(s):  
Electron Microscopy ◽  
Golgi Apparatus ◽  
Frontal Lobe ◽  
Synaptic Vesicles ◽  
Optic Lobe ◽  
Visual Cell ◽  
Visual Cells ◽  
Golgi Vesicles

Electron microscopy of the vertical lobe of octopus brain shows that the synaptic knobs of axons with perikarya in the median superior frontal lobe have synaptic vesicles, approximately 28% of which are dense-cored (or granulated). In contrast, the endings of the amacrine neurons in the vertical lobe and the endings in the retina and optic lobe, both of which are derived from the retinal visual cells, have only agranular synaptic vesicles. The Golgi apparatuses of the median superior frontal perikarya have vesicles, approximately 4.3% of which are granulated. The amacrine Golgi apparatuses have 1.5% granulated vesicles. The visual cell Golgi apparatuses have virtually no dense-cored vesicles, only agranular ones. The question of the formation of dense-cored and agranular synaptic vesicles at the Golgi apparatus and their subsequent transport to the terminals are related to these observations.

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