PubMed Health⌕ Search

Biomedical subjects

M Paterson

Publications and source records attributed to M Paterson.

At least 19 recordsLinked to original sources
PubMed1995

Redox regulation of tyrosine phosphorylation in human spermatozoa and its role in the control of human sperm function.

The redox status of human spermatozoa was found to have a profound influence on the fertilizing potential of these cells in association with qualitative and quantitative changes in the patterns of tyrosine phosphorylation. In general, oxidizing conditions enhanced tyrosine phosphorylation and stimulated sperm function, whereas reducing conditions had the opposite effect. Unstimulated human spermatozoa exhibited low levels of spontaneous acrosomal exocytosis and sperm-oocyte fusion and minimal reactive oxygen species generation, while phosphotyrosine expression was largely confined to a single protein of 116 kDa. However, if the spermatozoa were exposed to oxidizing conditions through the addition of exogenous H2O2, or the stimulation of endogenous NADPH-dependent reactive oxygen species generation, then a dramatic increase in tyrosine phosphorylation was observed (major phosphotyrosyl bands at 222 kDa, 200 kDa, 159 kDa, 133 kDa, 116 kDa and 82 kDa) in concert with the functional activation of the spermatozoa. A causal association between reactive oxygen species generation, tyrosine phosphorylation and sperm function was indicated by studies with the ionophore, A23187, which induced high rates of spermoocyte fusion together with enhanced rates of reactive oxygen species production and the increased expression of phosphotyrosyl proteins. This functional response to A23187 could be abrogated, without any concomitant change in sperm motility or viability, by using membrane permeant thiols or catalase to suppress the reactive oxygen species-induced increase in phosphotyrosine expression. The fact that the biological responses of human spermatozoa to biological agonists (recombinant human ZP3 and progesterone) could also be inhibited by catalase indicated the general relevance of these findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrosome↗
PubMed1992

Analysis of the contraceptive potential of antibodies against native and deglycosylated porcine ZP3 in vivo and in vitro.

We have undertaken a comparative analysis of the contraceptive activity of antibodies directed against the porcine sperm receptor zona pellucida antigen (ZP3) and its Mr = 32,000 polypeptide core (DGZP-32). The strategies employed for this analysis included the induction of active immunity in a primate, the common marmoset, and an in vitro fertilization protocol involving the use of viable human ova. In both experimental situations, antibodies against ZP3 were shown to exhibit contraceptive activity, leading respectively to the induction of long-term infertility in the primate model and to the complete inhibition of human fertilization in vitro. The in vivo studies also revealed that the induction of high titer antibodies against ZP3 was inevitably associated with the appearance of an ovarian pathology characterized by the progressive depletion of the primordial follicle pool within one to two years. This side effect could not be alleviated by the use of DGZP-32 as antigen since the induction of immunity against this polypeptide was also associated with the eventual appearance of an ovarian pathology identical to that observed with ZP3. Furthermore, the DGZP-32 peptide was less effective than ZP3 in inducing the formation of antibodies capable of inhibiting the fertilization of human ova in vitro. We conclude that significant problems remain with the use of deglycosylated zona peptides for the development of contraceptive vaccines and that their potential will not be realized until the epitopes responsible for the induction of infertility and the primordial follicle depletion have been identified and segregated.

Animals↗
PubMed1990

Phase II studies of ifosfamide alone and in combination in cancer of the cervix.

A series of phase II studies using ifosfamide (IFX) as a single agent and in combination with cisplatin and bleomycin (BIP) in advanced and recurrent cervical cancer have been coordinated at the West Midlands CRC Clinical Trials Unit (Birmingham, UK). The aims of these studies were to identify single agents and combination regimens that may be of value for palliation and have potential for use as neoadjuvant and adjuvant therapy at the time of primary treatment. A total of 79 patients with disease non-amenable to radical local therapy were treated with single-agent IFX or the BIP combination. In 30 patients treated with single-agent IFX, 10 objective responses (30%) were seen, with 1 complete response. In 49 patients treated with BIP, 34 objective responses (69%) were seen, with 10 complete responses (20%). Toxicity included alopecia, nausea and vomiting, myelosuppression, infection, reduction in renal function and disturbance of consciousness. These data indicate that IFX is highly active in cervix cancer and, in combination with bleomycin and cisplatin, can be used for effective palliation and cytoreduction in greater than 70% of patients. IFX-containing regimens have potential for use as neoadjuvant and adjuvant therapy in patients at high risk of recurrence with conventional treatment. These hypotheses are currently being tested in prospective randomised trials.

Adult↗
PubMed1990

Factors associated with childhood cancer in a national cohort study.

Information on 16,193 infants delivered in Great Britain in one week of April, 1970 was collected by midwives at the birth and during the first 7 days of life. Using multiple sources, 33 children developing cancer by 1980 were identified from this cohort, giving an incidence of 2.04 per 1,000 total births by the age of 10. Comparisons of these 33 children were made with 99 controls, three for each index case, matched on maternal age, parity and social class. Statistically significant associations were initially found with maternal X-rays and smoking during pregnancy, and the use of analgesics such as pethidine during labour, confirming the findings of retrospective case-control studies. Unexpected statistically significant associations were found with delivery of the child outside term, and drug administration in the first week of life. The latter was found in the absence of an association with neonatal abnormalities in the child and relates mostly to the administration of prophylactic drugs such as vitamin K. Logistic regression involving the whole cohort showed independent statistical associations with maternal smoking (OR 2.5), and drugs to the infant (OR 2.6). After adjusting for these factors no other statistically significant associations were found.

Adult↗
PubMed1989

Gradient high-performance liquid chromatography using alkylphenone retention indices of insecticidal extracts of Penicillium strains.

Purified extracts of four Penicillium strains which were active against the insect pest Spodoptera littoralis were analysed by gradient high-performance liquid chromatography (HPLC) for secondary metabolites using alkylphenone retention indices. HPLC of pure secondary metabolite standards detected previously in the extracts by thin-layer chromatography (TLC) was undertaken in order to obtain bracketed retention indices. More metabolites were detected by HPLC than by TLC, although some compounds detected by TLC in some strains were not detected by this HPLC method. A minority of metabolites were exclusive to each strain, and most were produced by more than one strain. The profiles were more characteristic of each strain when only the larger peaks were considered. This emphasizes the importance of detection limits in secondary metabolite analysis. Some of the implications of these analyses to fungus toxicity and systematic mycology are discussed.

Chromatography, High Pressure Liquid↗
PubMed1989

Combination bleomycin, ifosfamide, and cisplatin chemotherapy in cervical cancer.

We report a phase II study of bleomycin, ifosfamide, and cisplatin (BIP) in cervical cancer. Our aims were to assess response rate, toxicity, and survival in women treated with this combination. Among 49 patients, 34 objective responses (69%) were seen, with 10 complete responses (20%). Toxic effects were assessed in 186 treatment cycles. All patients had alopecia and nausea and vomiting. Other effects included myelosuppression, infection, reduction in renal function, and disturbance of consciousness. These data indicate that BIP is highly active against advanced and recurrent cervical cancer.

Adult↗
PubMed1989

The role of ifosfamide in cervical cancer.

A series of phase II studies using ifosfamide as a single agent and in combination with cisplatin and bleomycin (BIP) in advanced and recurrent cervical cancer were coordinated at the West Midlands Cancer Research Campaign Clinical Trials Unit, Birmingham, UK. The aim of these studies was to identify single agents and combination regimens that might be of value for palliation and have potential for neoadjuvant and adjuvant therapy in primary treatment. Ninety-eight patients were studied. Seventy-nine patients with disease not amenable to radical local therapy were treated with single-agent ifosfamide or the BIP combination. In 30 patients treated with single-agent ifosfamide, ten objective responses (33%) were seen, with one complete response. In 49 patients treated with BIP, 34 objective responses (69%) were seen, with ten complete responses (20%). Eleven (79%) of 14 patients with primary inoperable disease had at least a 50% reduction in tumor bulk before radical local radiotherapy. Toxicity resulted in alopecia, nausea and vomiting, myelosuppression, infection, reduction in renal function, and disturbance of consciousness. There was no evidence that neoadjuvant chemotherapy enhanced the acute toxic effects of pelvic radiotherapy. These data indicate that ifosfamide is highly active in cervical cancer and that in combination with bleomycin and cisplatin, it can be used for effective palliation and cytoreduction in around 70% of patients. Ifosfamide-containing regimens have potential for use as neoadjuvant and adjuvant therapy in patients at high risk of recurrence with conventional treatment. These hypotheses are currently being tested in prospective randomized trials.

Adult↗
PubMed1988

The cost effectiveness of auranofin: results of a randomized clinical trial.

In a 6-month randomized trial at 14 sites, the cost effectiveness of auranofin (AF) treatment for patients with rheumatoid arthritis was gauged in comparison with placebo. Measures of global health and of impacts on daily life suggest that the benefits of disease modification outweigh adverse effects after 4 and 6 months of treatment (p less than 0.01), with negligible differences between placebo and treated patients after 1 and 2 months. Additional medical costs directly associated with AF treatment amounted to $778/patient annually. Observed differences in less direct medical costs, help received, and earnings were not statistically significant.

Adult↗
PubMed1987

Genetic models for linkage analysis of ataxia-telangiectasia.

Ataxia-telangiectasia (AT) is a multifaceted autosomal recessive disorder, inherited as a single gene in each family, presumably due to a defective DNA processing protein such as a recombinase, endonuclease or even a regulatory DNA-binding protein. We are attempting to identify the chromosomal location of the AT gene(s) by performing linkage analyses on a variety of genetic models. At least five AT complementation groups have been defined. This genetic heterogeneity complicates linkage analysis. Model I assumes that the complementation genes are clustered into a single genomic region and, therefore, lod scores of linkage data from all families can be added. Model II assumes that the AT complementation genes are dispersed throughout the genome and the lod scores cannot be added. This model necessitates assigning the complementation group of every family that is included in the linkage analyses and reduces the number of families in each data base. Model III utilizes heterozygote identification to follow the AT gene (in a Group A pedigree of 61 members) as a dominant trait, thereby increasing the amount of linkage information that can be derived from that family. Model IV will focus only on consanguineous offspring of first-cousin marriages, seeking to identify the location of the AT gene(s) by the increased degree of homozygosity of genetic markers in close proximity. This model has several advantages, including that much smaller numbers of patients are required. Model V assumes that a subset of our patients will carry deletions and can be used to confirm the relationship of a candidate gene to the AT phenotype. Progress: Models I and II have been used to survey 7% and 2% of the genome, respectively. (An additional 5% of the genome can be added for exclusion of the X chromosome on clinical grounds). Model III is intended to survey the entire genome. Our initial studies have surveyed approximately 30% of the genome. Several areas of increased lod scores have been identified and are under further investigation.

Ataxia Telangiectasia↗
PubMed1986

Identification of a sequence containing the positive regulatory region of Saccharomyces cerevisiae gene ENO1.

A DNA fragment which contains the 5'-flanking region of the Saccharomyces cerevisiae enolase 1 gene (ENO1) and a portion of the coding sequence was cloned in a plasmid pMC1587. This fragment was fused in frame to the lacZ gene of Escherichia coli. Many mutants which deleted a portion of the 5'-flanking region of ENO1 were isolated from this ENO1-lacZ fusion plasmid by in vitro recombination. Analysis of beta-galactosidase activity of these mutants indicated that the regulatory region responsible for an efficient expression of the ENO1-lacZ fused gene resides within an 86-bp sequence located at -487 to -402 upstream from the start codon of ENO1. We found that the segment encompassing the 86-bp region worked equally well in an inverted orientation, but the tandem duplication of the sequence did not enhance the expression of the fused gene.

Bacterial Proteins↗
PubMed1986

Loosening of the femoral component after total hip replacement. The thin black line and the sinking hip.

Review of the radiographs of 882 consecutive metal-to-polyethylene hip replacements after a mean follow-up of 6.8 years showed 72 cases (8%) of aseptic femoral loosening, all of which showed a lucent zone or black line between metal and cement. In 97% of the series this appeared within two years of the arthroplasty. Progress of loosening was unpredictable and only 24% had significant symptoms. Improved technique with methylmethacrylate cement in Stanmore prostheses had reduced loosening after two years from 7.9% to 0.4%. Methods of detection of early loosening are discussed.

Follow-Up Studies↗
PubMed1985

Nucleotide sequence of the 5' flanking region responsible for the enhancement of the expression of yeast enolase 1 gene.

Several plasmids carrying different length of the 5' flanking region of yeast (Saccharomyces cerevisiae) enolase 1 gene (ENO1) which is fused in frame to the Escherichia coli lacZ gene were constructed by recombination in vitro. Promoter activity of ENO1 was assayed by measuring beta-galactosidase activity of the fused gene product. Comparison of the promoter activity of these plasmids suggests that the sequences required for a strong promoter activity lie within the DNA segment -724 to -353 base pairs (bp) upstream from the start of ENO1 coding sequence. The nucleotide sequence of this region was determined.

Base Sequence↗
PubMed1983

Iron uptake and regulation of ferritin synthesis by hepatoma cells in hormone-supplemented serum-free media.

Iron, as ferric nitrilotriacetate or ferric ammonium citrate, was administered to rat hepatoma cells (H4AZC2) that were grown in serum-containing media or in hormone-supplemented defined media on collagen matrices. High levels of iron either retarded growth or were cytotoxic, so conditions were established for maximum iron loading where cells survived at near normal growth rates. In all cases, cells exposed to iron produced more ferritin than those grown in its absence, and elevated ferritin levels were paralleled by higher intracellular iron contents. Cells grown in serum-free media, however, took up iron more rapidly than corresponding cells in serum-supplemented media, and intracellular iron and ferritin also reached much higher levels. During exponential growth stages, for example, ferritin levels in iron-stimulated cells were 35-fold greater than those in control cells. These results indicate that transferrin is not required as an iron donor as the inorganic iron was taken up effectively and utilized to stimulate ferritin synthesis. Twenty-four hours after iron administration, endocytotic mechanisms were evident by the appearance of coated vesicles and pits and visible cytoskeletal structures. Subsequently, clusters of iron micelles appeared in the cell. Ferritin isolated from iron-overloaded cells were rich in L-type subunits, but newly synthesized ferritins in iron-stimulated or control cells had almost equivalent amounts of heavy and light subunit constituents.

Animals↗
PubMed1982

How multiple sclerosis is related to animal illness, stress and diabetes.

At the University of Alberta's multiple sclerosis research clinic 100 patients with multiple sclerosis were matched to control patients for age, sex, race and zone of residence before the age of 15 years. Case and control subjects were interviewed and information was collected by questionnaire on factors that might play a role in the development of multiple sclerosis. The only factors found to be significantly associated with the development of this disorder were a history of leisure time spent in physical activities before the onset of symptoms, exposure to animal illness -- specifically canine distemper -- and a history of severe or prolonged emotional stress. The study also confirmed a familial predisposition to multiple sclerosis and suggested a relation between the disorder and a personal or family history of diabetes mellitus.

Adolescent↗
PubMed1981

The role of vitamin D metabolites in the osteomalacia of renal disease.

Osteomalacia is commonly found in patients with severe renal impairment. Its aetiology is multifactional and not simply due to deficient production of active metabolites of vitamin D. Decreased availability of calcium and phosphate and the accumulation of aluminium is some dialysis-treated patients are also important aetiological factors. The treatment of osteomalacia depends, in part, upon its accurate diagnosis, and identifying and reversing the underlying cause.

Calcium↗