scholarly journals STUDIES ON THE PSITTACOSIS-LYMPHOGRANULOMA GROUP

1953 ◽  
Vol 97 (6) ◽  
pp. 783-795 ◽  
Author(s):  
Emma G. Allen ◽  
Anthony J. Girardi ◽  
M. Michael Sigel ◽  
Morton Klein
Keyword(s):  
Virus Multiplication ◽  
Host Tissue ◽  
Time Interval ◽  
Chick Embryos ◽  
Virus Inoculation ◽  
Virus Growth ◽  
Inhibition Of Growth ◽  
The Brain ◽  
Direct Adsorption

The findings presented indicate that aureomycin could become associated with tissue of the chick embryo by both hematogenous distribution and direct adsorption. Treatment of chick embryos infected with MP virus with 1 mg. of aureomycin by the allantoic route caused an inhibition of virus growth in the allantoic membrane. The drug had no effect on "inert" virus, and appeared to have little effect on adsorption of virus to host tissue. Complete inhibition of growth during the time interval corresponding to the first cycle of multiplication could be achieved only if the drug was administered within 6 to 8 hours after virus inoculation. Partial inhibition of virus multiplication could be achieved even if the administration was delayed as late as 24 hours after infection. In these experiments the chief role of the antibiotic appeared to be one of virustasis reflected in a prolongation of the latent period (non-infectious phase). The virus was able to resume its growth when a critical low level of the drug in the allantoic membrane was reached. When infectivity titrations were carried out using various tissues and organs of treated and untreated embryos, it was found that no virus was detectable in the brains of treated embryos as late as 192 hours after inoculation of virus. This was in contrast with the findings in allantoic membranes and livers of such embryos; these organs showed virus at 120 and 144 hours, respectively. In untreated controls, virus appeared in membranes at 24 hours, in the liver at 48 hours, and in the brain at 72 hours.

scholarly journals The specification of noradrenergic locus coeruleus (LC) neurones depends on bone morphogenetic proteins (BMPs)

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 983-991 ◽  
Author(s):  
Astrid Vogel-Höpker ◽  
Hermann Rohrer
Keyword(s):  
Transcription Factors ◽  
Locus Coeruleus ◽  
Bone Morphogenetic Proteins ◽  
Chick Embryos ◽  
Dorsal Midline ◽  
Neural Crest Development ◽  
Roof Plate ◽  
Rhombic Lip ◽  
The Brain

The role of BMPs in the development of the major noradrenergic centre of the brain, the locus coeruleus (LC), was investigated. LC generation is reflected by initial expression of the transcription factors Phox2a and Phox2b in dorsal rhombomere1 (r1), followed by expression of dopamine-β-hydroxylase and tyrosine hydroxylase. Bmp5 is expressed in the dorsal neuroepithelium in proximity to Phox2-expressing cells. BMP inhibition in stage 10 chick embryos resulted in the lack of LC neurones or in their generation at the dorsal midline, and loss of roof plate and rhombic lip, but it did not affect neural crest development. These results reveal late essential BMP functions in the specification of dorsal neuronal phenotypes in r1, including LC neurones, and in the development of dorsal midline structures.

The Effect of Chloroacetophenone on Chick Embryos Cultured in vitro

Development ◽  
1962 ◽  
Vol 10 (3) ◽  
pp. 373-382
Author(s):  
M. S. Lakshmi
Keyword(s):  
Xenopus Laevis ◽  
Average Length ◽  
Primitive Streak ◽  
Poultry Farm ◽  
Chick Embryos ◽  
Normal Process ◽  
Strong Emphasis ◽  
The Brain

Brachet's (1950) strong emphasis on the role of —SH-containing proteins in the process of induction has stimulated a study of the interference in the normal process of morphogenesis of chick embryos by chloroacetophenone, which has been described by Beatty (1951) as a specific and irreversible —SH inhibitor. He studied the effect of chloroacetophenone on the development of embryos of Rana and Triturus employing different concentrations. Deuchar (1957) also studied the action of the same chemical on the embryos of Xenopus laevis and has recorded abnormalities mainly in the brain and the eye. In the present work ω-chloroacetophenone (CAP) commercially known as phenacyl chloride (ω—C6H5.CO.CH2Cl) was employed. The sample used was a B.D.H. product. Fresh fertilized hens' eggs brought from a local poultry farm were incubated at 37·5° C. for 16 to 18 hours to obtain definitive primitive-streak stages (range of length from 1·75 mm. to 2 mm.) or for about 22 hours to obtain head-process stages (average length of the head process alone 0·56 mm.).

scholarly journals Communication between the mediodorsal thalamus and prelimbic cortex regulates timing performance in rats

2021 ◽  
Author(s):  
Benjamin J De Corte ◽  
Kelsey A Heslin ◽  
Nathan Cremers ◽  
John H Freeman ◽  
Krystal L Parker
Keyword(s):  
Decision Making ◽  
Male Rats ◽  
Time Interval ◽  
Prelimbic Cortex ◽  
Motivational Systems ◽  
Starting Point ◽  
Reciprocal Connections ◽  
Future Events ◽  
The Brain

Predicting when future events will occur and adjusting behavior accordingly is critical to adaptive behavior. Despite this, little is known about the brain networks that encode time and how this ultimately impacts decision-making. One established finding is that the prefrontal cortex (PFC) and its non-human analogues (e.g., the rodent prelimbic cortex; PL) mediate timing. This provides a starting point for exploring the networks that support temporal processing by identifying areas that interact with the PFC during timing tasks. For example, substantial work has explored the role of frontostriatal circuits in timing. However, other areas are undoubtedly involved. The mediodorsal nucleus of the thalamus (MD) is an excellent candidate region. It shares dense, reciprocal connections with PFC-areas in both humans and non-human species and is implicated in cognition. However, causal data implicating MD-PFC interactions in cognition broadly is still sparse, and their role in timing specifically is currently unknown. To address this, we trained male rats on a time-based, decision-making task referred to as the 'peak-interval' procedure. During the task, presentation of a cue instructed the rats to respond after a specific interval of time elapsed (e.g., tone-8 seconds). We incorporated two cues; each requiring a response after a distinct time-interval (e.g., tone-8 seconds / light-16 seconds). We tested the effects of either reversibly inactivating the MD or PL individually or functionally disconnecting them on performance. All manipulations caused a comparable timing deficit. Specifically, responses showed little organization in time, as if primarily guided by motivational systems. These data expand our understanding of the networks that support timing and suggest that MD-PL interactions specifically are a core component. More broadly, our results suggest that timing tasks provide a reliable assay for characterizing the role of MD-PL interactions in cognition using rodents, which has been difficult to establish in the past.

The Role of Mitochondria in the Genesis of Neuroaxonal Dystrophy in the Brains of Aging Mice

1975 ◽  
Vol 33 ◽  
pp. 372-373
Author(s):  
J.E. Johnson
Keyword(s):  
Electron Microscopy ◽  
Present Report ◽  
Light And Electron Microscopy ◽  
Dorsal Column ◽  
Neuroaxonal Dystrophy ◽  
Nucleus Gracilis ◽  
Dystrophic Axons ◽  
The Brain ◽  
Nucleus Cuneatus

Although neuroaxonal dystrophy (NAD) has been examined by light and electron microscopy for years, the nature of the components in the dystrophic axons is not well understood. The present report examines nucleus gracilis and cuneatus (the dorsal column nuclei) in the brain stem of aging mice.Mice (C57BL/6J) were sacrificed by aldehyde perfusion at ages ranging from 3 months to 23 months. Several brain areas and parts of other organs were processed for electron microscopy.At 3 months of age, very little evidence of NAD can be discerned by light microscopy. At the EM level, a few axons are found to contain dystrophic material. By 23 months of age, the entire nucleus gracilis is filled with dystrophic axons. Much less NAD is seen in nucleus cuneatus by comparison. The most recurrent pattern of NAD is an enlarged profile, in the center of which is a mass of reticulated material (reticulated portion; or RP).

Effect of Dipyridamole on Spontaneous Platelet Aggregation in Whole Blood Decreases with the Time After Venepuncture: Evidence for the Role of ADP

1987 ◽  
Vol 58 (02) ◽  
pp. 744-748 ◽  
Author(s):  
A R Saniabadi ◽  
G D O Lowe ◽  
J C Barbenel ◽  
C D Forbes
Keyword(s):  
Platelet Aggregation ◽  
Correlation Coefficient ◽  
Whole Blood ◽  
Blood Platelet ◽  
Inhibitory Effect ◽  
Time Interval ◽  
Adp Receptor ◽  
Spontaneous Platelet Aggregation

SummarySpontaneous platelet aggregation (SPA) was studied in human whole blood at 3, 5, 10, 20, 30, 40 and 60 minutes after venepuncture. Using a whole blood platelet counter, SPA was quantified by measuring the fall in single platelet count upon rollermixing aliquots of citrated blood at 37° C. The extent of SPA increased with the time after venepuncture, with a correlation coefficient of 0.819. The inhibitory effect of dipyridamole (Dipy) on SPA was studied: (a) 10 μM at each time interval; (b) 0.5-100 μM at 3 and 30 minutes and (c) 15 μM in combination with 100 μM adenosine, 8 μM 2-chloroadenosine (2ClAd, an ADP receptor blocker) and 50 μM aspirin. There was a rapid decrease in the inhibitory effect of Dipy with the time after venepuncture; the correlation coefficient was -0.533. At all the concentrations studied, Dipy was more effective at 3 minutes than at 30 minutes after venepuncture. A combination of Dipy with adenosine, 2ClAd or aspirin was a more effective inhibitor of SPA than either drug alone. However, when 15 μM Dipy and 10 μM Ad were added together, the inhibitory effect of Dipy was not increased significantly, suggesting that Dipy inhibits platelet aggregation independent of Ad. The increase in SPA with the time after venepuncture was abolished when blood was taken directly into the anticoagulant containing 5 μM 2ClAd. It is suggested that ADP released from the red blood cells is responsible for the increased platelet aggregability with the time after venepuncture and makes a serious contribution to the artifacts of in vitro platelet function studies.

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

ROLE OF THE THYROID GLAND IN DEVELOPMENT AND MAINTENANCE OF RENAL HYPERTENSION IN RATS

1960 ◽  
Vol XXXIV (III) ◽  
pp. 411-429 ◽  
Author(s):  
Melvin J. Fregly ◽  
Kenneth M. Cook
Keyword(s):  
Blood Pressure ◽  
Rate Increase ◽  
Renal Hypertension ◽  
The Other ◽  
Elevated Blood Pressure ◽  
Unit Weight ◽  
Elevated Blood ◽  
Inhibition Of Growth ◽  
Testicular Size

ABSTRACT The anti-thyroid drugs, thiouracil, propylthiouracil, and methimazole, prevented both development of elevated blood pressure and cardiac hypertrophy usually accompanying kidney encapsulation with latex envelopes. These drugs also reduced elevated blood pressure of rats with hypertension of 13 to 40 weeks' duration prior to drug administration. Addition of desiccated thyroid powder to diet containing an anti-thyroid drug overcame the anti-hypertensive effect of the latter. Withdrawal of thyroid powder only was followed by return of blood pressure to previous low level within 3 weeks. The results suggest that the anti-hypertensive effect of these drugs is related directly to the hypothyroidism produced rather than to extrathyroidal effects of the drugs. Comparison of potencies of the 3 drugs in terms of anti-hypertensive effect, inhibition of growth rate, increase in testicular size, and increase in thyroid size suggests that propylthiouracil and methimazole are equally potent per unit weight of drug. Thiouracil has approximately half the potency of the other two.

Neuromyelitis optica spectrum: novel concept of pathogenesis, diagnosis and treatment of Devic’s disease

2009 ◽  
Vol 150 (46) ◽  
pp. 2101-2109 ◽  
Author(s):  
Péter Csécsei ◽  
Anita Trauninger ◽  
Sámuel Komoly ◽  
Zsolt Illés
Keyword(s):  
Neuromyelitis Optica ◽  
Water Channel ◽  
Diagnostic Procedures ◽  
Diagnosis And Treatment ◽  
Clinical Settings ◽  
Permanent Disability ◽  
Therapeutic Decisions ◽  
Novel Concept ◽  
The Brain

The identification of autoantibodies generated against the brain isoform water channel aquaporin4 in the sera of patients, changed the current diagnostic guidelines and concept of neuromyelitis optica (NMO). In a number of cases, clinical manifestation is spatially limited to myelitis or relapsing optic neuritis creating a diverse. NMO spectrum. Since prevention of relapses provides the only possibility to reduce permanent disability, early diagnosis and treatment is mandatory. In the present study, we discuss the potential role of neuroimaging and laboratory tests in differentiating the NMO spectrum from other diseases, as well as the diagnostic procedures and therapeutic options. We also present clinical cases, to provide examples of different clinical settings, diagnostic procedures and therapeutic decisions.

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