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R Porter

Publications and source records attributed to R Porter.

At least 145 records · Page 8Linked to original sources
PubMed1985

Responses of precentral cells during cooling of post-central cortex in conscious monkeys.

A cooling plate was implanted over the forelimb representation in area 2 of the post-central region of cerebral cortex in two monkeys. Recordings were made of the discharges of thirty-seven movement-related neurones (thirty-four precentral and three post-central) in the forelimb motor representation of the cerebral cortex during active and passively imposed limb movements before, during and after cooling area 2 and local surrounding regions. Perfusion of the cooling plate with ice-cooled water for 3-5 min caused marked clumsiness of the conscious animal's forelimb movement and anaesthesia of the contralateral hand. Cooling of area 2 did not reduce the responses of area 4 cells to passive joint movements, nor did it alter the over-all pattern of activity of these cells during self-initiated lever pulling while that could still be performed. Cooling of area 2 did cause a significant increase in background cellular discharge in area 4 while the animal was at rest. Afferent impulses which are generated by passive joint movement and which have been shown to influence cells in area 4 of the conscious monkey at short latencies are probably not transmitted through cortico-cortical connexions from area 2.

Animals↗
PubMed1985

[Not Available].

Explore the source record for details and available documents.

History, Modern 1601-↗
PubMed1985

Circulating and tissue concentrations of pregnancy-associated plasma protein-A (PAPP-A) in tubal ectopic gestation.

Concentrations of pregnancy-associated plasma protein-A (PAPP-A), human chorionic gonadotrophin (hCG) and pregnancy specific beta 1-glycoprotein (SP1) were measured by radioimmunoassay in 164 serum and 29 tissue samples obtained from 87 non-pregnant and 29 pregnant women with either tubal (n = 16) or intrauterine (n = 13) pregnancies. Of the 47 serum samples obtained from patients with a tubal pregnancy only two were positive for PAPP-A, whereas in excess of 94% of the samples were positive for both hCG and SP1. Serial measurements of hCG, and SP1, demonstrated an apparently normal growth rate for the tubally implanted trophoblast for the first 6 weeks of pregnancy. Thereafter, the tubal trophoblast is compromised since the tissue content of PAPP-A and hCG was significantly lower than that in intra-uterine derived trophoblastic tissue. By contrast, the content of both PAPP-A and hCG was significantly greater in the trophoblastic, both intra or extra-uterine derived, than in the endometrial/decidual, tissue. Furthermore, the absence of immunoreactive PAPP-A and the severely depressed circulating levels of PAPP-A in women with tubal pregnancies can be attributed to diminished secretion of PAPP-A into the maternal circulation. Therefore, in conjunction with a positive pregnancy test and the patient's clinical history, a severely depressed or absent serum PAPP-A level may aid in the diagnosis of extrauterine pregnancy.

Chorionic Gonadotropin↗
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↗