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Biomedical subjects

M J Stapleton

Publications and source records attributed to M J Stapleton.

11 recordsLinked to original sources
PubMed1999

Immobilized sample amplification for quantitative determination of retroviruses.

Immobilized sample amplification (ISA) is a novel method for amplification, detection, monitoring, and quantitative determination of nucleic acids from a minute amount of sample. We present here a novel quantitative ISA assay for retroviruses using a replication-defective recombinant retrovirus as a model retrovirus. Samples, as small as 5 to 10 microl or as large as 1 ml or more in volume, are readily immobilized on a nylon or polyester matrix. Retroviral RNA is directly amplified following the rehydration of the immobilized samples, thus eliminating the needs for retroviral RNA extraction. An ISA assay of a 10-microl viral sample generates results equal to or better than that of RT-PCR on equivalent amount RNA isolated from larger sample volumes. Recovery of RNA from small volumes, such as 10 microl, is almost impossible, whereas ISA assay detects retroviruses from as small as 1 to 5 microl of viral samples containing 10(4) cfu/ml determined by colony-forming assay. Extraction of RNA from a small amount of infectious viral samples not only is a difficult, biohazardous procedure, but also introduces random errors which contribute to variability in viral quantitation. Since the ISA method eliminates the isolation/extraction of the nucleic acids, it significantly shortens the handling time for the biohazardous materials and simplifies the procedure for analyzing small quantities of biological samples. This method detects less than 10 infectious retroviral particles as determined by both colony-forming assay and electron microscope studies. The format and protocol of this quantitative ISA assay can be easily automated to fit into numerous platforms, thus making it attractive for laboratory automation.

3T3 Cells↗
PubMed1991

The inverted nipple: to cut the ducts or not?

Much dilemma exists as whether to divide the lactiferous ducts or not when correcting an inverted nipple. We report a series of 26 cases (44 nipples), which have undergone correction with or without duct division. Eversion was maintained in 59% of nipples. Analysis of the failure groups revealed similar rates of failure for umbilicated nipples whether the ducts were divided (27%) or not (25%). Invaginated nipples showed an increased tendency to reinvert postoperatively if the ducts were not divided (80%) than if they were (42%) (not significant). Permanent loss of nipple sensation was noted in 20% of cases when the lactiferous ducts were divided. Postoperatively two women were able to breast feed despite complete division of their lactiferous ducts. Women with umbilicated nipples are usually able to breast feed. We believe that correction of the umbilicated nipple can usually be successfully performed, and function maintained without dividing the ducts. Correction of the invaginated nipple requires duct division. The underlying pathogenesis and varying methods of correction are reviewed.

Adolescent↗
PubMed1986

Post-mastectomy breast reconstruction: the soft tissue alternative.

The available methods of soft tissue reconstruction of the breast are described. They are usually preferable to the use of a prosthesis. For unilateral reconstruction the appropriate method depends on the age of the patient and the size of the breast. In an elderly patient with large breast, a two-stage breast-sharing procedure is advocated. In a young patient with a small breast, an extended latissimus dorsi myocutaneous flap provides a suitable reconstruction. In a middle-aged woman with a breast of moderate size and an adequate amount of abdominal subcutaneous tissue, the most appropriate method of reconstruction is a rectus abdominis myocutaneous flap. For bilateral reconstruction where the consistency is less important, a prosthesis, with or without a latissimus dorsi flap for cover, is the method of first choice.

Abdomen↗
PubMed1985

Selective inhibition of the accumulation of extracellular proteases of Pseudomonas aeruginosa by gentamicin and tobramycin.

Gentamicin and tobramycin inhibited the accumulation of extracellular proteases secreted by Pseudomonas aeruginosa. The secretion of protease was inhibited at concentrations of these drugs that were below the level required to inhibit general protein synthesis. Neither magnesium ions nor high ionic strength antagonized the ability of the aminoglycosides to block secretion of the proteases. Under these culture conditions magnesium ions were shown to antagonize the effects of the aminoglycosides on protein synthesis and aminoglycoside-mediated lysozyme lysis of P. aeruginosa. These results suggested that the drugs blocked secretion of the proteases by acting at the level of the outer membrane.

Culture Media↗
PubMed1984

Soft tissue reconstruction of the breast using an extended composite latissimus dorsi myocutaneous flap.

A method of breast reconstruction using the whole of the latissimus dorsi muscle is described in which the usual skin flap is extended to include a large de-epithelialised flap of dermis and subcutaneous tissue from the loin to provide the necessary augmentation with living tissue rather than with a prosthesis. The method can be used as a reliable one-stage reconstruction, without a prosthesis, either secondarily or as a synchronous combined procedure at the time of the mastectomy.

Adult↗
PubMed1984

Transposon mutagenesis of Pseudomonas aeruginosa exoprotease genes.

Transposon Tn5 was used to generate protease-deficient insertion mutants of Pseudomonas aeruginosa. The presence of Tn5 in the chromosome of P. aeruginosa was demonstrated by transduction and DNA-DNA hybridization. The altered protease production and kanamycin resistance were cotransduced into a wild-type P. aeruginosa strain. A radiolabeled probe of Tn5 DNA hybridized to specific BamHI fragments isolated from the insertion mutants. Two independently isolated Tn5 insertion mutants had reduced protease production, partially impaired elastase activity, and no immunologically reactive alkaline protease.

Conjugation, Genetic↗
PubMed1981

Post-mastectomy breast reconstruction using a direct flap from an abdominal lipectomy.

If a patient requires a breast reconstruction and at the same time is a candidate for an abdominal lipectomy, it is possible to combine the operation and carry out a breast reconstruction using a direct flap from the abdominal wall. The technique of this two-stage operation is described. In suitable cases one can produce a breast resembling the normal without any obvious scarring to detract from the result and without the complication of a silastic prosthesis.

Abdominal Muscles↗
PubMed1977

Reconstruction of the breast following radical mastectomy.

A method of reconstruction of the breast following radical mastectomy is presented. The technique involves the use of an individually made Silastic prosthesis inserted three to six months after the mastectomy. A new simple method of nipple reconstruction is described, and the total restoration can be achieved in one operation. It is suggested that reconstruction of the breast be considered more frequently in patients subjected to mastectomy.

Breast↗