The gametophyte and young sporophyte of Ampelopteris prolifera

1969 ◽  
Vol 47 (12) ◽  
pp. 1953-1959 ◽  
Author(s):  
D. Mittra ◽  
U. Sen
Keyword(s):  
Usual Type ◽  
Short Filament ◽  
Young Sporophyte

The spores of Ampelopteris prolifera (Retz.) Copel. are bilateral and have a smooth exine and a folded perine. The gametophyte arises as a short filament which soon develops into a spatula, and ultimately becomes cordate at maturity. In overcrowded cultures the prothallus is a variously branched filament. Mature gametophytes may develop filamentous or cordate branches. Hairs with extracellular apical cap-like secretions originate both at the margin and on the surfaces of the prothallus. In old prothalli peg-like outgrowths develop on the superficial sides of the wing. The antheridia and archegonia are of the usual type found in the evolutionally advanced ferns. The development of the young sporophyte is described and illustrated. The taxonomic validity of the genus is also discussed.

A SCREENING TEST FOR LONG-ACTING CORTICOTROPHIN PREPARATIONS

1964 ◽  
Vol 46 (2) ◽  
pp. 279-284 ◽  
Author(s):  
Claus Rerup ◽  
Pavo Hedner
Keyword(s):  
Screening Test ◽  
Subcutaneous Administration ◽  
High Plasma ◽  
Systemic Effect ◽  
Usual Type ◽  
End Point ◽  
Long Acting

ABSTRACT The mouse assay for corticotrophin, using plasma steroid levels as the response, is shown to be suitable with slight modifications as a screening test for long-acting corticotrophin. Four hours after the subcutaneous administration of 10–20 milliunits of corticotrophin in saline, the plasma steroid levels had virtually returned to the preinjection levels, whereas corticotrophin injections in combination with 15 per cent gelatine or 1 per cent polyphloretin phosphate, resulted in sustained high plasma steroid levels. Unlike the usual type of prolongation (e. g. insulin, testosterone) which is characterized by delayed maximal end-point readings, peak responses were observed at the same time following prolonged or non-prolonged corticotrophin. Significantly higher responses were observed following long-acting preparations at this time (one hour after the injection). The test also enables the investigator to distinguish between a local and systemic effect of the prolonging material. Thus it was shown that polyphloretin phosphate and gelatine were active only when given in local combination with corticotrophin. The advantages of the method together with its limitations for the assessment of a long-acting effect in man are briefly discussed.

Patterns of Myo-neural Junctions and Cholinesterase Activity in the Muscles of Tadpoles of Xenopus Laevis

1960 ◽  
Vol s3-101 (53) ◽  
pp. 55-67
Author(s):  
P. R. LEWIS ◽  
A.F. W. HUGHES
Keyword(s):  
Xenopus Laevis ◽  
Convenient Method ◽  
Azo Dye ◽  
Cholinesterase Activity ◽  
Muscle Fibres ◽  
Striated Muscles ◽  
Usual Type ◽  
Special Adaptation ◽  
Slow Type ◽  
Axial Musculature

A simultaneous coupling azo dye technique has been used to reveal the distribution of cholinesterase activity in the musculature of the developing tadpole of Xenopus laevis. The use of inhibitors and a less convenient but more specific histochernical technique confirmed that only true cholinesterase distribution was being demonstrated; and a study of silver-impregnated material proved that this azo dye technique provides a very convenient method of following the development of the patterns of myo-neural junctions in the striated muscles of this tadpole. A wide variety of patterns is seen in the various muscles: in the axial musculature the muscle-fibres become innervated at their ends from myocommatal plexuses and never acquire endings along their length; broad muscular sheets, as in the walls of the branchial and abdominal cavities, are also first innervated terminally from the septa but later acquire secondary innervation is along the lengths of the fibres. These different patterns of innervation are correlated with the functions of the various types of muscle. It is suggested that terminal innervation may be a special adaptation to permit rapid establishment of neurogenic activity, the pattern of endings of the more usual type forming when the need for precisely co-ordinated reflexogenic activity arises. In some muscles, the azo dye technique reveals a profuse multiple innervation of the fibres which are assumed to be of the so-called ‘slow type’ known to exist in some amphibian muscles.

II.—A Matrix Notation for Mendelian Populations

1934 ◽  
Vol 53 ◽  
pp. 7-25 ◽  
Author(s):  
Lancelot Hogben
Keyword(s):  
Contingency Table ◽  
Single Gene ◽  
Sex Linkage ◽  
Matrix Notation ◽  
Usual Type ◽  
Preliminary Account ◽  
Male Sex

Those who have had experience of problems involving inbreeding or the correlation of relatives in a population with specified proportions of Mendelian genotypes will have realised what difficulties reside in the absence of a convenient notation. In the absence of such a notation difficulties arise more from the unwieldiness of the expressions obtained than the abstruseness of the problems encountered. The familiar chessboard diagrams of Mendelian hybridisation and the form of a contingency table for relatives alike suggest that a matrix notation might be generalised to take into account both sex-linked inheritance and the more usual type of transmission. A determinant form would meet some of the requirements of autosomal transmission; but is not adapted to the asymmetrical case, when the male sex cannot be heterozygous. In extending to more remote relationships a previous inquiry (3) into fraternal and filial correlations involving sex linkage, the writer has found it useful to employ a system of operations applicable to other types of inquiry. The former investigation is not yet complete. In the meantime it seemed possible that the method used might prove suggestive to other workers. A preliminary account of the fundamental operations is here given in so far as they are relevant to single gene substitutions.

Gains of chromosome region 3q26 in intraepithelial neoplasia and invasive squamous cell carcinoma of the vulva are frequent and independent of HPV status

2008 ◽  
Vol 61 (9) ◽  
pp. 1034-1037 ◽  
Author(s):  
S Aulmann ◽  
J Schleibaum ◽  
R Penzel ◽  
P Schirmacher ◽  
G Gebauer ◽  
...  
Keyword(s):  
Squamous Cell ◽  
P53 Protein ◽  
In Situ Hybridisation ◽  
Intraepithelial Neoplasia ◽  
Squamous Cell Carcinomas ◽  
Invasive Squamous Cell Carcinoma ◽  
Fluorescence In Situ Hybridisation ◽  
P53 Expression ◽  
Usual Type ◽  
Hpv Status

Aims:Two different forms of vulvar intraepithelial neoplasia (VIN) are recognised: (1) usual-type (bowenoid) VIN, which is related to high-risk papillomavirus infection, and (2) differentiated (simplex) VIN, which is associated with chronic inflammation. The aim of this study was to investigate the presence of chromosome 3q26 gains in the spectrum of precancerous lesions and invasive squamous cell carcinomas (SCCs) of the vulva.Methods:3q26 gains were analysed using fluorescence in situ hybridisation in a series of usual-type VINs, VINs of the differentiated type and invasive squamous cell carcinomas. In addition, all cases were examined for human papillomavirus (HPV) DNA, p53 mutations, and p16 and p53 protein expression.Results:Gains of chromosome 3q26 were present in all VINs of the differentiated type and in 50% of the usual-type VIN lesions. 81% of SCCs were positive for 3q26 gains irrespective of the HPV status and of the associated precursor lesion. HPV-associated lesions exhibited the typical, strong cytoplasmic p16 accumulation while mutated p53 was only detected in HPV-negative VINs or SCCs, and was associated with an overexpression of p53 protein.Conclusions:Immunohistochemical evaluation of p16 and p53 expression aids in the differential diagnosis of squamous cell alterations of the vulva. However, detection of 3q26 imbalance is of additional diagnostic value in difficult cases of HPV-unrelated usual-type VINs and VINs of the differentiated type.

Approximate equivalence of group actions

2017 ◽  
Vol 38 (4) ◽  
pp. 1201-1237 ◽  
Author(s):  
ANDREAS NÆS AASERUD ◽  
SORIN POPA
Keyword(s):  
Group Actions ◽  
The Other ◽  
Equivalence Relations ◽  
Orbit Equivalence ◽  
Usual Type ◽  
New Concepts ◽  
Probability Spaces ◽  
Measure Preserving Actions

We consider several weaker versions of the notion of conjugacy and orbit equivalence of measure preserving actions of countable groups on probability spaces, involving equivalence of the ultrapower actions and asymptotic intertwining conditions. We compare them with the other existing equivalence relations between group actions, and study the usual type of rigidity questions around these new concepts (superrigidity, calculation of invariants, etc).

SECONDARY BIFURCATIONS AND SYMMETRY BREAKING AS A ROUTE TOWARDS SPATIOTEMPORAL DISORDER

1995 ◽  
Vol 05 (03) ◽  
pp. 841-848 ◽  
Author(s):  
M.R.E. PROCTOR ◽  
J. LEGA
Keyword(s):  
Symmetry Breaking ◽  
Order Parameter ◽  
Periodic Pattern ◽  
Long Wavelength ◽  
Usual Type ◽  
Secondary Bifurcations ◽  
Low Order

We analyse an equation describing long-wavelength transverse instabilities of a roll-like periodic pattern that has solutions which undergo a series of transitions between states with different symmetries as the order parameter is changed. The transitions appear when the solutions are already chaotic and so are not bifurcations of the usual type. We investigate the first of these transitions in detail, and relate the results to those of a simple low order truncation of the governing p.d.e.’s.

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