Search PubMed⌕ Search

Biomedical subjects

A Becker

Publications and source records attributed to A Becker.

At least 487 records · Page 27Linked to original sources
PubMed1978

The palatally impacted canine: a new approach to treatment.

A method for the application of traction to misplaced maxillary canines in the palate is described. The treatment approach is from the palatal side, with initial traction applied in a lingually downward direction to prevent interference with the neighboring teeth. Emphasis is placed on the suitability of the method as an adjunct to almost any of the established techniques. In this way improving their efficiency in treating the over-all orthodontic problem.

Child↗
PubMed1978

Enzymatic breakage of the cohesive end site of phage lambda DNA: terminase (ter) reaction.

An in vitro system is described for measuring the endonucleolytic conversion of the phage lambda cohesive end sites in concatemeric DNA to the cohesive chromosomal ends of the mature molecule. This enzymic process, known as the ter reaction, is catalyzed by purified lambda A gene protein. The reaction is markedly stimulated by ATP, Mg2+, spermidine, and one or more uncharacterized factors present in extracts of uninfected Escherichia coli cells. In vitro, the ter reaction proceeds in the absence of proheads under conditions that are similar to those previously found necessary for the formation of a DNA-A gene protein intermediate for the initiation of packaging.

Adenosine Triphosphate↗
PubMed1978

Non-routine extractions in orthodontic treatment.

A four-unit symmetrical premolar extraction case demands meticulous levelling, overjet reduction, space closure, rotating, paralleling and torqueing to justify the gambit of having extracted the teeth at the commencement of treatment. This involves the patient in complex therapy which may, for any of several reasons, be contra-indicated for that particular patient, though a decision based on the plaster casts alone may have upheld such an approach. The purpose of this article is to discourage automatic decisions to extract first premolars in orthodontic extraction cases. The clinician is offered a classification of special cases in which an alternative should be sought, based on careful consideration of the general dental, facial, physical, psychological and economic state of the patient.

Acute Disease↗
PubMed1977

Monozygosity in twins: a detailed investigation.

The twins presented in this article showed similarities in their physical make-up to a very high degree. Statistically, however, it is the blood picture which holds the "trump card" in this plethora of evidence supporting monozygous twinning, and it is an essential prerequisite in any presentation of this nature. It is perhaps noteworthy that, while only one of the twins sucked his thumb habitually, there was no difference in the degree of postnormality of the posterior teeth but merely a change in the interincisor relation and in the palatal height. It can clearly be seen from the study of these two twins that the differences between them were very small indeed and could quite easily be classed as individual variations within the same identical genetic pattern. Similarly, in any other identical twins, the way in which one differs from another must be to a similarly small degree or the cause of the difference must clearly be attributable to environmental or acquired influences. Differences which cannot be classed as other than genetic show us that the twins are fraternal or dizygous and, therefore, no more alike than would be two brothers of differing ages.

Blood Chemical Analysis↗
PubMed1977

Assembly of biologically active proheads of bacteriophage lambda in vitro.

Bacteriophage lambda DNA can be packaged in vitro into preformed proheads to generate plaque-forming units. This complex set of reactions is initiated when lambda DNA is mixed with the product of the phage A gene, and proheads. Because proheads are an essential early reactant, the system has potential as an assay for the formation of biologically active proheads. When extracts of cells infected with certain lambda head mutants (for example, B--, C--, Nu3--, and E--) are used as the prohead donor, plaque-forming units are not produced. However, when extracts of E- - and Nu3- - infected cells are first reacted together the combination provides prohead-donor activity to the in vitro packaging system. In vitro assembled, biologically active proheads have the same sedimentation properties and electron micrsocopic appearance as "wild-type" proheads isolated from lambdaA-D- -infected cells. Centrifugation analysis shows that the Nu3- extract contributes gpE, the major capsid protein, to the reaction in the form of monomers or small polymers.

Coliphages↗