Search PubMed⌕ Search

Biomedical subjects

R Porter

Publications and source records attributed to R Porter.

At least 145 records · Page 8Linked to original sources
PubMed1984

Ultrasonic assessment of endometrial changes in stimulated cycles in an in vitro fertilization and embryo transfer program.

Four distinct patterns in the ultrasonic appearance of preovulatory endometrium can be identified and described in patients undergoing stimulated cycles in an in vitro fertilization program. Ultrasonically, this endometrial response can be seen as a quantitative change in thickness and a qualitative change in gray-scale appearance or reflectivity. The application of this additional parameter of endometrial assessment together with the conventional measurement of follicular diameter as a means of optimally timing oocyte collection has been associated with a reduction in the preoperative ovulation rate from 10.9 to 3.2%, an increase in the fertilization rate from 59.2 to 82.5%, and in a pregnancy rate per embryo transfer of 20.5% in our program without the use of hormonal assays.

Cell Separation↗
PubMed1984

The relationship between spinal canal diameter and back pain in coal miners. Ultrasonic measurement as a screening test?

Back pain is the commonest cause of absence among coal miners. However, the degree of morbidity is variable. To determine whether the susceptible individual can be identified, ultrasound was used to measure the spinal canal diameters of 204 miners. The results show that those men with the longest histories and the longest times off work and those who had to leave the coalface or who left the industry--i.e., those with the greatest morbidity--had significantly narrower canals. Ultrasonic measurement of the spinal canal diameter is safe and noninvasive. Its use should be further evaluated as part of a preemployment screening procedure for back pain.

Age Factors↗
PubMed1984

Spontaneous abortion--an infectious aetiology?

The role of Chlamydia trachomatis, genital mycoplasmas, Campylobacter spp. and other aerobic and anaerobic bacteria in the aetiology of spontaneous abortion was investigated prospectively in 241 pregnant women at a community hospital. Sixteen women who had threatened abortions were a little younger, of lower social class and had had more previous spontaneous abortions than the 76 women who aborted or the 149 women whose pregnancies were not complicated in the early stages by haemorrhage. The demographic characteristics of the latter two groups of women were similar. C. trachomatis was isolated from the cervix of only one woman and she had no genital-tract bleeding at any stage in her pregnancy. Mycoplasma hominis was isolated most often from the women who had threatened abortions but otherwise the prevalence of the other various micro-organisms was similar in women who had spontaneous abortions, threatened abortions, and in those who had pregnancies uncomplicated by vaginal bleeding. It was clear, therefore, that C. trachomatis played no role in the aetiology of spontaneous abortion in the population studied and there was no suggestion that any of the other micro-organisms were involved either.

Abortion, Spontaneous↗
PubMed1984

Pregnancy-associated plasma protein A in human ovarian follicular fluid.

Human ovarian follicular fluid contains pregnancy-associated plasma protein A (PAPP-A) immunoreactivity as detected by RIA. This PAPP-A was found to be stable to repeated freeze-thaw cycles and not removed by dialysis. Further characterization showed that ovarian follicular PAPP-A bound reversibly to heparin-Sepharose. On gel chromatography follicular PAPP-A coeluted with radioiodinated PAPP-A and pregnancy serum PAPP-A which was determined to have an apparent mol wt of 820,000. In the RIA, serial dilutions of high molecular weight heparin-Sepharose binding proteins gave parallel displacement curves to pooled late pregnancy serum and to the International Reference Preparation, WHO 78/610. All the human ovarian follicular fluids tested had PAPP-A concentrations between 0.317-1.595 IU/liter. The relationship between follicular content of PAPP-A and follicular volume was best expressed by the exponential relationship, y = 164.3 e0.117x. Therefore, ovarian follicular fluid PAPP-A has many physico-chemical similarities to and shares immunological identity with pregnancy-derived PAPP-A. As this pregnancy-associated glycoprotein cannot be detected in the circulation of normal non-pregnant adults, its presence within the Graafian follicle is believed to be of intrafollicular origin for the maintenance of proteolytic homeostasis.

Chromatography, Affinity↗
PubMed1983

Plasticity of motor behavior in monkeys with crossed forelimb nerves.

Monkeys in which nerves innervating the flexor muscles of the forearm and hand (the ulnar or the median nerve) had been surgically cross-united with the nerve innervating the extensor muscles (the radial nerve), and vice versa, showed excellent (ulnar-radial crosses) to moderate (median-radial crosses) control of movement performance after regeneration. Antagonistic movement responses were seen occasionally, but these were corrected almost immediately. Stimulation of the crossed nerves showed that they had innervated the antagonistic muscle groups. The results reveal the capacity of the primate central nervous system to adapt to gross disturbances imposed on the execution of movements by changes in peripheral innervation.

Animals↗
PubMed1983

Supplementary motor area and premotor area of monkey cerebral cortex: functional organization and activities of single neurons during performance of a learned movement.

In the conscious, behaving monkey trained to perform a motor task either self-paced or involving light cues, a restricted area responsive during performance of the task can be found in cytoarchitectonic area 6 at the level of the concavity of the arcuate sulcus. Within this area, different groups of neurons can be identified in relation to experimental variables. First a group related in its activity to specific aspects of movement performance. Second, a group associated with movements and visual events, and third, a group modulated in its activity throughout the execution of the task. A few neurons are related to visual cues only. In the first group, a subpopulation exists of neurons active with movements of either extremity; this group resembles similar neurons in SMA. Such neurons can be associated with proximal or distal movements suggesting PM is not an area involved mainly in the maintenance of body posture. The PM may function as a visuomotor integration center as evidenced by the large number of neurons influenced by visual aspects of the tasks. This is also suggested by findings in lesion studies in monkeys and man. Studies in conscious monkeys and man point to a role for PM in motor learning, when a new motor program is established or a previously learned one modified.

Afferent Pathways↗
PubMed1982

Shutting people up.

Explore the source record for details and available documents.

History, Ancient↗