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Biomedical subjects

P Jackson

Publications and source records attributed to P Jackson.

At least 145 records · Page 8Linked to original sources
PubMed1991

A multiple high-resolution mini two-dimensional polyacrylamide gel electrophoresis system: imaging two-dimensional gels using a cooled charge-coupled device after staining with silver or labeling with fluorophore.

A multiple mini two-dimensional electrophoretic method which results in three two-dimensional protein spot patterns being positioned side by side in an individual gel has been developed. Preparation time has been minimized by employing disposable capillary tubes for the isoelectric focusing gels and reducing the number of second-dimensional gels required. Commercially available vertical slab units were used for the second-dimensional electrophoresis. The protein spot patterns were visualized either by staining the second-dimensional gel with silver or fluorescently labeling the focused proteins while present in the isoelectric focusing gel and subsequently electrophoresing them into the second-dimensional gel. The fluorescently labeled second-dimensional gel was imaged while still present in the glass mold immediately following electrophoresis. Two fluorophores were compared: 2-methoxy-2,4-diphenyl-3(2H)-furanone and 5-(4,6-dichlorotriazin-2-yl)aminofluorescein hydrochloride. A rapid imaging system based on a cooled charge-coupled device was used to view both the silver-stained and fluorescently labeled two-dimensional spot patterns. The sensitivity of detection of protein spots in the mini two-dimensional gels was similar for the two types of fluorescently labeled gels and the silver-stained gels.

Cell Line↗
PubMed1991

Polyacrylamide gel electrophoresis of reducing saccharides labeled with the fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid: application to the enzymological structural analysis of oligosaccharides.

Mono- and oligosaccharides, each containing a reducing end group, were labeled with the charged fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid and the resulting derivatives were separated with high resolution by polyacrylamide gel electrophoresis using a method developed recently (P. Jackson, Biochem. J. 1990, 270, 705-713) but with an alternative electrophoretic buffer system. The fluorescent derivatives of glucose and all its straight chain, alpha 1-4 linked, oligomers from maltose to maltoheptaose were well resolved. Various isomers such as maltose and lactose could be separated, as were maltose and cellobiose and some epimers, for instance glucose and galactose. The method was applied to the analysis of the partial sequential degradation of a complex oligosaccharide with neuraminidase and beta-galactosidase. Gels showing fluorescent saccharide band patterns were recorded in picomolar quantities either photographically or using an imaging system based on a cooled charge-coupled device.

Electrophoresis, Polyacrylamide Gel↗
PubMed1991

Establishing pregnancies after follicular stimulation for IVF with clomiphene citrate and human menopausal gonadotrophin only.

Data are presented on establishing pregnancies by IVF during 1987 using only clomiphene citrate and human menopausal gonadotrophin for follicular stimulation. Of the 562 patients undergoing follicular stimulation, 80% reached oocyte recovery and 70% had at least one conceptus replaced. Patients having one or more (up to a maximum of four) conceptuses replaced demonstrated a significant increase in the establishment of pregnancies from one to two (14-29%: P = 0.035) and from two to three conceptuses (29-42%: P = 0.037). There was a significant decline in pregnancies when four conceptuses were replaced compared with three (P = 0.004). The data were also analysed according to the cause of infertility, specifically tubal, endometriosis, unexplained infertility and male factors only. After the replacement of conceptuses, the incidence of implantation and abortion was not significantly different. The incidence of pregnancy declined significantly after 35 years (26%) compared with women under 31 years (43%; P = 0.043). Of 129 women having three conceptuses replaced, in those greater than 35 years (63 patients) 23 (37%) became pregnant whereas in those less than 31 years (65 patients), 34 (52%; P = 0.05) became pregnant. Twenty-two per cent of stimulated cycles resulted in an endogenous LH surge and the incidence of patients having three conceptuses replaced in this group was lower than those in the HCG group (P = 0.007). Fertilization per oocyte was also significantly reduced (P less than 0.001) in patients with an LH surge. In total, 2824 oocytes were recovered and 57% fertilized with 54% of patients having three conceptuses replaced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Presentation of six pregnancies established by sub-zonal insemination (SUZI).

Clinical trials were undertaken to evaluate sub-zonal insemination (SUZI) for the procurement of fertilization in infertile couples. We present here the six pregnancies resulting from this work. Insemination of multiple sperm was used, with a mean of 3.7 +/- 2.1 (SD) per oocyte. One hundred and thirty patients presented either with previous failures of fertilization in vitro and/or with severe seminal defects, including oligo-, astheno-, oligo-astheno- or necro-zoospermia. Forty-one (31.5%) patients achieved fertilization and 39 had replacement of conceptuses. Six patients achieved a pregnancy (4.6% overall, 15.4% per replacement), four have delivered and two have miscarried. The implantation rate was nine conceptuses from a total of 61 replaced (14.8%); and of the six women who conceived, nine of 11 replaced conceptuses implanted. Of the oocytes recovered, 539 were used for SUZI, of which 69 (12.8%) fertilized. Three singleton pregnancies resulted, two from patients having one conceptus replaced, the other from the replacement of three conceptuses. Two twin pregnancies were produced, both in patients having two conceptuses replaced. The sixth pregnancy, a triplet, occurred in a patient having three conceptuses replaced, one conceived after standard in-vitro fertilization (IVF), the other two after SUZI. Two sets of non-identical twins, both one male and one female, a singleton female and female (non-identical) triplets have been born, normal and healthy.

Adult↗
PubMed1991

The use of the GnRH analogue buserelin for IVF--does it improve fertility?

OBJECTIVE: To determine the effect of a short course of the GnRH analogue buserelin and human menopausal gonadotrophin (hMG), for ovarian stimulation in our IVF programme, on reproductive endocrinology and pregnancy rates compared with conventional clomiphene citrate and hMG treatment. DESIGN: Prospective randomized allocation to one of two ovulation stimulation regimens. SETTING: Fertility clinic. SUBJECTS: 373 infertile couples with various factors associated with their subfertility. All the women were less than 46 years of age and had normal menstrual cycles. INTERVENTION: The first group (n = 151) was given clomiphene citrate (CC) from days 2-6 of the menstrual cycle and hMG from day 5 onwards (CC/hMG). The second group (n = 222) was given buserelin from days 1-3 and hMG from day 2 (buserelin/hMG). MAIN OUTCOME MEASURES: Concentration of plasma luteinizing hormone (LH), oestradiol (E2) and progesterone, number of ovulatory follicles induced and the occurrence of pregnancy. RESULTS: Plasma LH, E2 and progesterone concentrations were reduced in the late follicular phase after buserelin/hMG compared with CC/hMG. Buserelin/hMG promoted the development of more follicles than CC/hMG. The overall pregnancy rate after buserelin/hMG was not significantly different from that following CC/hMG treatment. CONCLUSION: The chance of pregnancy is not improved by the short-term use of buserelin with hMG, provided adequate follicular phase management is maintained.

Adult↗
PubMed1991

Activation of phosphatidylinositol 3-kinase in cells expressing abl oncogene variants.

A phosphoinositide kinase specific for the D-3 position of the inositol ring, phosphatidylinositol (PI) 3-kinase, associates with activated receptors for platelet-derived growth factor, insulin, and colony-stimulating factor 1, with products of the oncogenes src, fms, yes, crk, and with polyomavirus middle T antigen. Efficient fibroblast transformation by proteins of the abl and src oncogene families requires activation of their protein-tyrosine kinase activity and membrane association via an amino-terminal myristoylation. We have demonstrated that the PI 3-kinase directly associates with autophosphorylated, activated protein-tyrosine kinase variants of the abl protein. In vivo, this association leads to accumulation of the highly phosphorylated products of PI 3-kinase, PI-3,4-bisphosphate and PI-3,4,5-trisphosphate, only in myristoylated, transforming abl protein variants. Myristoylation thus appears to be required to recruit PI 3-kinase activity to the plasma membrane for in vivo activation and correlates with the mitogenicity of the abl protein variants.

Animals↗
PubMed1990

The use of polyacrylamide-gel electrophoresis for the high-resolution separation of reducing saccharides labelled with the fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid. Detection of picomolar quantities by an imaging system based on a cooled charge-coupled device.

Various monosaccharides, oligosaccharides and small polysaccharides were labelled covalently at their reducing end groups with the fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid (ANTS), and the resulting fluorescent derivatives were separated by high-resolution PAGE. The electrophoretic mobilities of the labelled saccharides are related largely to the compounds' Mr values, but they are also influenced by the individual chemical structures of the saccharides. Various positional isomers and some epimers, for instance galactose and glucose, were resolved. Oligosaccharide and small polysaccharide derivatives, prepared from an enzymic digest of starch, each differing in size by a single hexose residue and with a range of degrees of polymerization from 2 to 26, were all resolved in a single gel. The method was relatively rapid and simple to perform. It enabled multiple samples to be analysed in parallel with high sensitivity. The fluorescent-labelling procedure was virtually quantitative. As little as 1 pmol of ANTS-labelled saccharide was detected photographically when the gels were illuminated by u.v. light. When the gels were viewed using an imaging system based on a cooled charge-coupled device, as little as 0.2 pmol was detected. The method may be useful for the structural analysis of the carbohydrate moieties of glycoconjugates and other naturally occurring oligosaccharides.

Animals↗
PubMed1990

Structure-activity relationships of antifilarial antimycin analogues: a multivariate pattern recognition study.

The structure-activity relationships of a series of novel antifilarial antimycin A1 analogues have been investigated by using computational chemistry and multivariate statistical techniques. The physiochemical descriptors calculated in this way contained information which was useful in the classification of compounds according to their in vitro antifilarial activity. This approach generated a 53 parameter descriptor set, which was reduced with a multivariate pattern recognition package, ARTHUR. Regression analysis of the reduced set yielded several statistically significant regression equations; e.g.-log in vitro activity = 0.017 mp + 0.65 log P - 0.81ESDL10-7.33 (R = 0.9). With use of this equation, it was possible to make predictions for further untested analogues. The analysis indicated that membrane or lipid solubility is an important determinant in biological activity agreeing with the proposed primary mode of action of the compounds as disrupters of cuticular glucose uptake.

Animals↗
PubMed1990

Oestrogen receptor in breast cancer: prognostic studies using a new immunohistochemical assay.

A recently developed and validated histochemical method--immunogold-streptavidin enhancement--was used to determine oestrogen receptor content in paraffin sections of breast cancers. The selection of the best cut-off point to define oestrogen receptor status as rich or poor was made on the basis of survival data, using the following indices: survival to term; disease-free interval; survival at 5 years; and disease-free interval at 5 years. Oestrogen receptor status was examined in relation to histological grade, lymph node status, menopausal status and tumour size and these four indices were considered as independent prognostic factors. Semi-quantitative assay of receptor content showed that increasing content was related to better prognosis. Adjuvant therapy alone had no effect on patient outcome. Independently, histological grade and lymph node status, but not menopausal status or tumour size, were prognostic indicators. Oestrogen receptor rich status, as measured by immunogold-streptavidin, in conjunction with certain of these factors indicated a better prognosis. This was comparable with results in reports using other methods of receptor assay. We found the oestrogen receptor status and menopausal status more significant at 5 years than at term. The advantage of immunogold-streptavidin enhancement, which we found as reliable as other methods for oestrogen receptor assay, is that it can be used on archival, routinely paraffin-processed material.

Breast Neoplasms↗
PubMed1990

Application of 1 nm gold probes on paraffin wax sections for in situ hybridisation histochemistry.

An in situ hybridisation technique that uses 1 nm immunogold reagents and silver enhancement was devised to detect biotinylated DNA viral probes in formalin fixed, paraffin wax sections of human cervix. DNA probes labelled with biotin-11-deoxyuridine triphosphate were detected after hybridisation to nucleic acid sequences by an antibiotin antibody, followed by a gold labelled secondary antibody. Silver enhancement then permitted visualisation of the signal at the light microscopic level. The method was reliable and produced less background staining than previously described methods. The signal could be enhanced by epi polarisation microscopy. Furthermore, biotinylated DNA probes may be detected directly by a 1 nm gold labelled goat antibiotin antibody without loss of labelling intensity, and this may be preferable to the longer two layer technique, previously described.

Animals↗
PubMed1990

Subzonal insemination for the alleviation of infertility.

Methods were developed to facilitate the use of subzonal insemination to achieve fertilization in vitro. A clinical trial was undertaken in those patients having previously failed to achieve fertilization by in vitro fertilization, and in those presenting with severe oligospermia/oligoasthenospermia. From 85 patients, 585 oocytes were obtained. Of these, 0.3% had been "activated" parthenogenetically in vivo, 369 (72%) at metaphase II underwent subzonal insemination, 15% were fertilized, and 0.5% had three pronuclei. Thirty-eight percent of the patients had fertilization with 36% having a replacement. One conceptus was replaced in 19 patients, two conceptus in 8 patients, and three in 4 patients. A twin and two singleton pregnancies were established.

Adult↗
PubMed1990

An inexpensive electronic counting system for step tests.

A simple electronic counter was designed to count step test cadence. Foot pads, a controller and a counter were used to record the number of times the subject placed both feet on the top step. The electronics insured accurate counting by preventing double counts on one ascent and requiring weight to be put on both feet on the top step.

Electronics, Medical↗
PubMed1989

Role of community pharmacies in prevention of AIDS among injecting drug misusers: findings of a survey in England and Wales.

OBJECTIVE: To determine the current and potential roles of community pharmacists in the prevention of AIDS among misusers of injected drugs. DESIGN: Cross sectional postal survey of a one in four random sample of registered pharmacies in England and Wales. SETTING: Project conducted in the addiction research unit of the Institute of Psychiatry, London. SUBJECTS: 2469 Community pharmacies in the 15 regional health authorities in England and Wales. MAIN OUTCOME MEASURES: Willingness of pharmacists to sell injecting equipment to known or suspected misusers of drugs; pharmacists' attitudes to syringe exchange schemes, keeping a "sharps" box for use by misusers of drugs, and offering face to face advice and leaflets; and opinions of community pharmacists on their role in AIDS prevention and drug misuse. RESULTS: 1946 Questionnaires were returned, representing a response rate of 79%. This fell short of the target of one in four pharmacies in each family practitioner committee area in England and Wales, and total numbers of respondents were therefore weighted in inverse proportion to the response rate in each area. The findings disclosed a substantial demand for injecting equipment by drug misusers. After weighting of numbers of respondents an estimated 676 of 2434 pharmacies were currently selling injecting equipment and 65 of 2415 (3%) were participating in local syringe exchange schemes; only 94 of 2410 pharmacies (4%) had a sharps box for used equipment. There was a high degree of concern among pharmacists about particular consequences of drug misusers visiting their premises, along with a widespread acceptance that the community pharmacist had an important part to play. CONCLUSIONS: Promoting the participation of community pharmacists in the prevention of AIDS among misusers of injected drugs is a viable policy, but several problems would need to be overcome before it was implemented.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The mouse type IV c-abl gene product is a nuclear protein, and activation of transforming ability is associated with cytoplasmic localization.

The subcellular localization of the mouse type IV c-abl protein was determined by indirect immunofluorescence of nontransformed NIH 3T3 fibroblasts that overexpress the protein. Unlike the viral transforming protein p160gag/v-abl, which has cytoplasmic and plasma membrane localization, a large fraction of the c-abl (IV) protein is nuclear, with the remainder in the cytoplasm and plasma membrane. Deletion of a small N-terminal regulatory region of the c-abl (IV) protein, sufficient to activate its transforming potential fully, changes the distribution of the protein from the nucleus to the cytoplasm. Mapping of an amino acid sequence responsible for the nuclear localization of the c-abl (IV) protein reveals a nuclear localization signal similar to that of SV40 large T antigen.

Amino Acid Sequence↗