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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 433 records · Page 24Linked to original sources

Carrier determination for X-linked agammaglobulinemia using X inactivation analysis of purified B cells.

We report the development of a relatively quick and simple method for the assessment of X inactivation status for carrier determination in families affected by X-linked agammaglobulinemia (XLA). This method utilises an immunomagnetic separation technique for B cell purification and a polymerase chain reaction (PCR) based assay for the determination of methylation status at the androgen receptor (AR) gene locus to assess whether X inactivation is random or non-random at this locus. We report the results we have obtained using this assay to investigate females known to be carriers of various X-linked immunodeficiency disorders. In addition, we investigated four females from different families affected by XLA, two of whom were of unknown carrier status, and we discuss the results obtained with this and other X-inactivation assays. A similar assay has recently been described by Allen et al. (1992) and applied to members of one family affected by XLA.

Agammaglobulinemia↗

Value of faecal alpha-1-antitrypsin, haemoglobin and a chemical occult blood test in the detection of gastrointestinal disease.

Specimens from hospital out-patients and in-patients sent for faecal occult blood tests were also analysed for faecal alpha-1-antitrypsin and faecal haemoglobin. 453 stool specimens from 222 patients were analysed. The clinicians were only aware of the faecal occult blood test results, and diagnoses were made using conventional clinical and investigative criteria. Gastrointestinal bleeding or putative sites of bleeding were diagnosed in 98 patients, whereas in 81 patients putative sites of bleeding were not found or other cause of anaemia diagnosed. In 41 patients there was insufficient information to reach a definitive diagnosis. Comparison of the 3 faecal tests using these grouping methods showed that faecal alpha-1-antitrypsin performed best, with an accuracy of 89%, specificity of 90% and sensitivity of 88%, all significantly better (P < 0.001) than the faecal occult blood test (68%, 60% and 73%, respectively). There was no significant difference between the performance of the faecal occult blood and faecal haemoglobin tests. Faecal alpha-1-antitrypsin measurement may be a useful investigation in situations where a faecal occult blood test would normally be requested.

Adolescent↗

Analytical methods for differentiating minor sequence variations in related peptides.

A proline-rich peptide was isolated and purified to homogeneity from an extract of bovine neutrophil granules using semi-preparative RP-HPLC. The relative molecular mass of the peptide (called Bac-X) was determined by ionspray MS to be 5149 +/- 0.5. The amino acid composition of the peptide was characterized by its limited number of amino acid types, which included a high proline (43.3%) and arginine content (20.3%), and hydrophobic residues. Bac-X had similar characteristics to Bac-5, a previously characterised bactenecin of bovine neutrophil granules, with respect to its proline, arginine and hydrophobic amino acid content, molecular mass and antibacterial specificity. Tryptic and N-bromosuccinimide digestion of Bac-X produced fragments with masses (M(r) 785 and 4224 and 3100 respectively) consistent with those expected from a peptide with the reported sequence of Bac-5. Bac-X differed from Bac-5 in the number of amino acid residues (43 for Bac-X versus 42 for Bac-5) and contained glycine which Bac-5 did not. However, the calculated molecular mass of the peptide, based on the amino acid compositional data, did not match the experimental value. The purified peptide could not be sequenced by Edman degradation due to apparent blockage of the N-terminus. Partial sequence information, obtained by LC-MS and collision induced dissociation MS-MS analysis of a M(r) 785 tryptic fragment of Bac-X, showed that this peptide contained a six residue sequence (-RFPPIR-) not found in Bac-5 which, based on its reported sequence, contained a M(r) 785 tryptic fragment with the sequence -FRPPIR-. This difference in sequence of Bac-X compared with Bac-5 illustrates the application of electrospray (ionspray) MS techniques to the detection and identification of minor differences in related protein/peptide forms.

Amino Acid Sequence↗

Characterisation of TNF-alpha-related peptides by high-performance liquid chromatography-mass spectrometry and high-performance liquid chromatography-tandem mass spectrometry.

Ion-spray triple quadrupole mass spectrometry and high-performance liquid chromatography were used to investigate the products from the solid phase synthesis of (H)-Leu-Thr-Glu-Asn-(OH), a TNF-alpha active-site probe. The target sequence was assembled using tert.-butoxycarbonyl (Boc) chemistry in stepwise fashion from the C-terminal on an Boc-Asn-OCH2-Pam-copoly(styrene-divinylbenzene) resin [Pam = 4-(carboxamidomethyl)benzyl ester]. The crude product was deprotected and cleaved from the resin by HF-p-cresol treatment for 1 h at 0 degrees C. HPLC analysis at 214 nm indicated two late-eluting major products and an early-eluting product. Preparative HPLC demonstrated that the early-eluting product contained ca. 80% of the expected recovered sample mass. Each component was then directly analysed by mass spectrometry and tandem mass spectrometry. The early eluting peak was confirmed as the desired LTEN sequence. Synthesis of the same sequence using 9-fluorenyl methoxycarbonyl (Fmoc) chemistry gave an identical product and confirmed the above analysis. The most significant by-product was derived from arylation of the glutamyl group by the quencher p-cresol. The likely origins of the by-products are discussed.

Amino Acid Sequence↗

Processing of chimeric mammalian cytochrome b5 precursors in Escherichia coli: reaction specificity of signal peptidase and identification of an aminopeptidase in post-translocational processing.

A chimeric precursor interlinked by an arginine residue between the full-length signal sequence of alkaline phosphatase and the eukaryotic cytoplasmic cytochrome b5 was constructed. Expression of the chimeric precursor protein in Escherichia coli resulted in efficient export of spectrally authentic cytochrome b5 into the periplasm [Karim, Harding, Evans, Kaderbhai and Kaderbhai (1993) Bio/Technology 11, 612-618]. On sequencing, the apparent absence of arginine at the N-terminus of the secreted cytochrome b5 implied that the chimera was either miscleaved by signal peptidase or further processed following signal excision by an uncharacterized peptidase. The influence of the N-terminal region of cytochrome b5 on the unusual processing of the chimeric precursor was investigated by engineering a number of variant forms in which the region between Arg+1 and the mature portion of cytochrome b5 was extended and varied. Observations of the in vivo processed patterns of these variant cytochrome b5 forms exported into the periplasm revealed that the absence of arginine was due to neither miscleavage of the translocated precursor by the signal peptidase nor the nature of the early region of cytochrome b5. In fact, the selective excision of the arginine residue occurred subsequent to signal sequence deletion by an aminopeptidase which was sensitive to the metal chelator o-phenanthroline. We show that this aminopeptidase also participates in the trimming of the N-terminal arginine residue of the bacterial alkaline phosphatase to generate the three isoenzymes in the periplasm.

Amino Acid Sequence↗

Sexual behavior.

Explore the source record for details and available documents.

Aged↗

Rapid prenatal diagnosis of Patau's syndrome in a fetus with an abdominal wall defect by 72 hour culture of cells from amniotic fluid.

A woman in the 32nd week of pregnancy was referred for investigation because of fetal abnormalities, including an abdominal wall defect, detected by ultrasonography. In view of the increased risk of chromosome abnormality, amniocentesis was performed to enable informed decisions about the management of the pregnancy and delivery to be taken. Cells from the liquor were inoculated into standard lymphocyte culture medium and incubated for 72 h. Slides with a high mitotic index and good quality metaphases, comparable to those from a blood culture, were obtained after harvesting. Cytogenetic analysis showed the karyotype to be 46,XY, - 14,+t(13q14q), which is consistent with Patau's syndrome. This technique appears to be an option for rapid karyotyping in cases of abdominal wall defect, where a chromosomal abnormality is suspected.

Abdominal Muscles↗

The reconstruction and expression of a Bacillus thuringiensis cryIIIA gene in protoplasts and potato plants.

A Bacillus thuringiensis (B.t.) cryIIIA delta-endotoxin gene was designed for optimal expression in plants. The modified cry gene has the codon usage pattern of an average dicot gene and does not contain AT-rich nucleotide sequences typical of native B.t. cry genes. We assembled the 1.8 kb cryIIIA gene in nine blocks of three oligonucleotide pairs. For two DNA blocks, the polymerase chain reaction was used to enrich for correctly ligated pairs. We compared modified cryIIIA gene with native gene expression by electroporation of dicot (carrot) and monocot (corn) protoplasts. CryIIIA-specific RNA and protein was detected in carrot and corn protoplasts only after electroporation with the rebuilt gene. Transgenic potato lines were generated containing the redesigned cryIIIA gene under the transcriptional control of a chimeric CaMV 35S/mannopine synthetase (Mac) promoter. Out of 63 transgenic potato lines, 58 controlled first-instar Colorado potato beetle (CPB) larvae in bioassays. Egg masses which produced ca. 250,000 CPB larvae were placed on replicate clones of 56 transgenic potatoes. No CPB larvae developed past the second instar on any of these plants. Plants expressing high levels of delta-endotoxin were identified by their toxicity to more resistant third-instar larvae. We show there was good correlation between insect control and the levels of delta-endotoxin RNA and protein.

Amino Acid Sequence↗

Medicinal plant inventory of Kuna Indians: Part 1.

Results of an ethnopharmacognostic survey of 90 plants used by the Kuna Indians of San Blas Islands, who live in Ailigandí, are listed. Results of a literature search are also reported, including medical uses, known constituents and pharmacological effects.

Humans↗

Sodium cromoglycate via inhaler and Autohaler.

One hundred and eighty-one children with asthma were entered into a randomized, controlled, crossover study comparing sodium cromoglycate via a metered dose inhaler (MDI) and a breath-actuated inhaler (Autohaler). There were no significant differences in pulmonary function tests (FEV1, FVC, PFER), symptom scores and bronchodilator use between the two devices. However both patients' and clinicians' opinions of sodium cromoglycate effectiveness were significantly better (P < 0.01) for the Autohaler. Autohaler was also thought to be easier to use (P < 0.001) and better for co-ordination of actuation with inhalation (P < 0.001). The Autohaler is as efficacious as the metered dose inhaler used by good co-ordinators. It seems to be the significantly better device with respect to ease of use, actuation and co-ordination which may aid compliance.

Adolescent↗

The role of percutaneous nephrostomy in malignant urinary tract obstruction.

Percutaneous nephrostomy is a well established technique for rapid relief of ureteric obstruction and improvement of renal function. However, its role in the management of renal failure resulting from advanced abdominopelvic malignancy is controversial and there are no clear guidelines to predict which patients benefit from such intervention both in terms of survival time and quality of life. To establish a protocol for selection of patients with abdominopelvic malignancy most likely to benefit from nephrostomy for renal obstruction, the medical records of 50 consecutive patients undergoing this procedure at the Royal Marsden Hospital were reviewed. The patients were divided into four groups: Group I, renal obstruction caused by a nonmalignant complication as a result of previous surgery or radiotherapy (n = 8); Group II, renal obstruction due to untreated primary malignancy (n = 16); Group III, renal obstruction from relapsed disease with a viable treatment option (n = 8); and Group IV, relapsed disease with no conventional treatment option (n = 18). There was significant benefit from percutaneous nephrostomy in Groups I-III. The overall median survival time of Group IV patients was extremely poor: 38 days (range 6-143 days) with no long-term survivors. The results suggest that strict selection criteria should be applied to patients with a history of abdominopelvic malignancy before proceeding to percutaneous nephrostomy. No worthwhile benefit is obtained if nephrostomy is used as a palliative measure in the absence of definitive treatment.

Female↗

Urinary-derived monocyte-colony stimulating factor (P-100) following treatment with carboplatin and etoposide in small cell lung cancer (SCLC).

BACKGROUND: The hematopoietic growth factor P-100 is a monocyte-colony stimulating factor purified from human urine and has been reported to reduce neutropenia following chemotherapy. In this study the effect and toxicity of P-100 was evaluated in 26 patients receiving intensive chemotherapy for SCLC. STUDY DESIGN: Chemotherapy consisted of four 28 day cycles of carboplatin (C) 600 mg/m2 i.v. on day 1 of cycle 1 + 2 and 300 mg/m2 i.v. on day 1 of cycle 3 + 4 and etoposide (E) 120 mg/m2 i.v. on day 1-3 of each cycle. Patients were randomised to receive P-100 for ten days following chemotherapy during either the first or second cycle. 12 Patients received P-100 with the first and 12 with the second cycle. For each group cycles with P-100 were compared to cycles without P-100. RESULTS: P-100 was well tolerated but no significant differences between cycles with and without P-100 were seen in the administered chemotherapy dose, depth and duration of neutropenia, number of blood or platelet transfusions, WHO grade 3-4 infection or requirement for intravenous antibiotics. Of 24 evaluable patients 14 (58.3%) achieved CR and 4 (16.6%) PR. Patients achieving CR received radiotherapy. The median time to progression was 169 days (range 38-995+ days) and the median survival time was 305 days (range 42-1052+ days). Three patients are alive after 2 years (11.5%), 2 without relapse (7.7%). Alopecia, nausea and vomiting occurred in all patients but no treatment related deaths occurred. CONCLUSION: In this study P-100 did not significantly influence the myelotoxicity associated with carboplatin-etoposide chemotherapy in the treatment of SCLC.

Adult↗

Is osteoarthritis in women affected by hormonal changes or smoking?

The influence of sex hormone related events and smoking on the development of OA in women was investigated in a case-controlled postal survey. One hundred and twenty-nine patients with nodal generalized osteoarthritis (NGOA) and 145 with non-nodal pauciarticular large joint osteoarthritis (LJOA) were identified from the database of a Nottingham OA clinic. For each patient, three age-matched controls were randomly selected from the same general practice. Sixty-three per cent of questionnaires (690/1096) were returned: NGOA, 95; NGOA controls, 226; LJOA, 113; LJOA controls, 256. There were no differences in age at menarche or menopause, rates of hysterectomy, oral contraceptive use, or hormone replacement use between cases and controls. Fewer OA patients had ever smoked [(Odds Ratio (OR) 0.65, 95% Confidence Interval (CI) 0.45-0.95)] and subset analysis demonstrated that this negative association occurred only in the LJOA group (OR 0.43, CI 0.25-0.72), particularly in those with knee OA (OR 0.29, CI 0.14-0.62). A previous successful pregnancy was negatively associated with NGOA (OR 0.47, CI 0.24-0.95). This study demonstrates no association between oestrogen-related hormonal events and OA, but a negative association between smoking and LJOA. Such data supports the concept that OA is a heterogeneous disease and underlines the need to differentiate OA subsets.

Age Factors↗

Continuous flow resectoscopes. Are the theory and design wrong?

The optical design of rod-lens telescopes has now reached a zenith. The only way of improving the resectoscope is to investigate the ergonomics and flow dynamics. We present a comparative analysis of the flow mechanics of continuous flow resectoscopes. The morphology, flow characteristics and irrigating potential (washout gradient) of several instruments were examined. It was found that when used with balanced continuous flow (inflow and outflow balanced), all of the endoscopes had poor visibility compared with unbalanced continuous flow (inflow > outflow). Possible changes in the design of the instruments are discussed.

Endoscopes↗