The MD and MS degrees in Britain.

Higher medical degrees--MD and MS--have been awarded at an increased rate since 1980, owing partly to increased numbers of medical graduates and partly to greater career competition. The pass rate has not changed since 1965. Regulations at various universities show substantial differences, particularly in the use of viva voce examinations for failed candidates, in permissible subject matter, and in allowing the submission of previously published papers. As these degrees are important for careers, and are registrable by the General Medical Council, it is suggested that it should issue minimal standards to be observed by all universities.     

Requirements of British universities for higher medical degrees.

OBJECTIVE--To examine the requirements and opportunities for obtaining a doctor of medicine or master of surgery degree from a university in the United Kingdom other than the graduate''s own, particularly in the case of foreign graduates. DESIGN--Review of regulations governing the award of doctor of medicine and master of surgery degrees in British universities. SETTING--All 19 universities in the United Kingdom offering clinical courses. MAIN OUTCOME MEASURE--Availability of degrees to graduates of other universities. RESULTS--Opportunities for obtaining a degree differed widely among the medical schools, one university (Edinburgh) not admitting graduates of other universities in any circumstance. Of the remaining universities, none would consider a graduate who had not worked in the area where the medical school was located. CONCLUSION--The wide differences in opportunity among the medical schools may put some foreign graduates at a disadvantage compared with other graduates. This problem may become more severe as the number of graduates from the European Community who settle in Britain increases.     

Post-natal development of brown adipose tissue in the rat bred at 23 degrees C or 28 degrees C.

In view to study the effects of thermal environment on the development and the thermogenic activity of interscapular brown adipose tissue (BAT), young rats born at 23 degrees C or 28 degrees C were sacrificed at 1, 3, 7, 11, 14 or 21 days after birth. The rate of increase in animal weight was quite the same at both temperatures up to the 14th day. The development of BAT and its contents in lipids, in water and in noradrenaline indicate that the energetic activity of the tissue is greatly stimulated in rats kept at 23 degrees C up to the 11th day. It is concluded that in rats bred in the habitual thermal conditions (23 degrees C), the occurrence of non shivering thermogenesis (NST) is important during the period of ten days after birth; in the following period NST could be progressively replaced by other thermoregulatory processes.     

Species of Pseudomonas obtained at 7 degrees C and 30 degrees C during aerobic storage of lamb carcasses.

A total of 268 strains of Pseudomonas isolated during storage life of lamb carcasses was identified to species level. One-hundred and thirteen strains obtained at 30 degrees C were Ps. fragi (51), Ps. lundensis (17), Ps. fluorescens biovars I (10), III (9) and VI (1), Ps. putida biovar A (8 strains) and unidentified (17 strains). Species and biovars isolated at 7 degrees C (155) were Ps. fragi (101), Ps. lundensis (32), Ps. fluorescens biovar I (6), Ps. putida biovar A (8) and unidentified (8). Numerical analysis (82% SSM, UPGMA) of 'psychrotrophic' and 'mesophilic' strains resulted in the formation of nine and eight clusters respectively. The dendrograms obtained exhibited similar structures. Most of the strains of Ps. lundensis and Ps. fragi clustered together. Strains of this latter species also joined the type strain of Ps. testosteroni and appeared included with phenons containing the Ps. putida strains. There were clusters made up exclusively of strains assigned to one biovar or group (Ps. fluorescens biovars I and II and unidentified). A high level of similarity was observed between clusters of Ps. fluorescens biovar I and those containing the Ps. fragi-Ps. lundensis complex (> 74% SSM) and Ps. lundensis (> 80%). The recovery of pseudomonads seemed to be affected by the sampling day.     

Short-term preservation of mouse oocytes at 5 degrees C.

The temporary preservation of oocytes without freezing would be useful for some experiments. ICR mouse oocytes were kept in a preservation medium under mineral oil for 1, 2, 3, 4 or 7 days at 5 degrees C, and 1 or 2 days at 37 degrees C. In vitro fertilization was attempted on oocytes rinsed with TYH medium after preservation. More than 70% of morphologically normal oocytes were recovered from each preservation group. Fertilization rates of oocytes preserved for 1, 2, 3, 4 or 7 days at 5 degrees C were 69.9, 66.5, 45.3, 26.7 and 8.8% respectively. Fertilization rates of oocytes preserved for 1 or 2 days at 37 degrees C were 9.6 and 1.6%, respectively. Preservation of oocytes at 5 degrees C has some capability as a method of short-term storage without freezing.     

Real-time imaging of the reorientation mechanisms of YOYO-labelled DNA molecules during 90 degrees and 120 degrees pulsed field gel electrophoresis.

Pulsed field gel electrophoresis (PFGE) techniques have been developed to overcome the limitations of conventional electrophoresis and to increase the separation to DNA chromosomes of few megabase pairs in size. Despite of the large success of these techniques, the various separation protocols employed for PFGE experiments have been determined empirically. However, a deep understanding of the molecular mechanisms of motion responsible for DNA separation becomes necessary for the rational optimization of these techniques. This paper shows the first clear observations of individual molecules of DNA during the reorientation process in 90 degrees PFGE and 120 degrees PFGE. Real-time visualization of the DNA dynamics during PFGE was possible with the use of an epi-illumination fluorescence microscope specifically equipped to run these experiments and by staining the DNA with YOYO-1 (1,1'-(4,4,7,7-tetramethyl-4,7-diazaundecamethylene)-bis-4-[3-meth yl -2,3-dihydro-(benzo-1,3-oxazole)-2-methyl-idene]-quinolinium tetraiodide). This dye forms a very stable, highly fluorescent complex with double-stranded DNA and dramatically improves the quality of the DNA images. The results of computer simulations used to reproduce the molecular mechanisms of motion as well as the DNA separation features are also discussed.     

Ultrastructure of Aplysia neurons having different degrees of light sensitivity.

The relationship between ultrastructure and photosensitivity of pigmented neurons of the abdominal ganglion of Aplysia californica was investigated using electron microscopy and electrophysiological methods. Four identified neurons of similar light microscopic appearance were examined; two are photoresponsive and two are not. Illumination hyperpolarizes both responsive neurons. One of them, R2, requires roughly 100 times greater light intensities than does the other, the ventral photoresponsive neuron (VPN), for similar responses. Two neurons lying adjacent to VPN and similar in appearance to VPN do not have measurable electrophysiological responses to even the highest light intensities. All four neurons contained lipochondria, pigmented organelles associated with the light response. Therefore the presence of these organelles is not the only requirement for light sensitivity in these neurons. Illumination appeared to increase the number of membranous lipochondria in both R2 and the ventral neurons, but only in R2 was this increase significant. Factors such as the concentration of lipochondria near the plasma membrane may affect quantitative aspects of the light response, but in the insensitive cells the lipochondria are apparently uncoupled from other factors required for the light response.     

Thermal transformation of cholecalciferol between 100--170 degrees C.

Cholecalciferol is transformed, irreversibly, to pyrocholecalciferol and isopyrocholecalciferol. The rate constant, as a function of temperature, for this transformation from the equilibrium mixture of cholecalciferol and precholecalciferol has been determined for temperatures between 100--170 degrees C and is slower than the precholecalciferol-cholecalciferol interconversion. The ratio of rates of production of pyro to isopyro derivatives is 2:1 throughout.