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Biomedical subjects

J McCann

Publications and source records attributed to J McCann.

At least 109 records · Page 6Linked to original sources
PubMed1994

Microvascular replantation of a completely avulsed scalp.

Total scalp avulsion is an unusual injury. To obtain good functional and cosmetic results, immediate revascularization using microsurgical techniques and replacement of the scalp in the correct anatomical position is the procedure of choice. This article describes a case report of successful replantation of a totally avulsed scalp from a 26-year-old male. Bilateral superficial temporal vessel anastomoses were performed using reversed autologous long saphenous vein grafts on the right side and direct repair on the left. Points of technique are discussed and the literature is reviewed.

Accidents, Occupational↗
PubMed1994

Results of clinical assessment after primary digital nerve repair.

We have carried out a retrospective study of 88 consecutive digital nerve repairs in 84 patients who presented to this department between September 1989 and September 1991. 94% of the patients were operated on within 24 hours of the injury, and the nerves were repaired using magnifying loupes (x 4.5) 71 patients were assessed clinically 8 to 32 months post-operatively. 17% of the patients had excellent results, 51.1% good results, 22.8% fair results and 9.1% had poor results. Close correlation between age and recovery of sensation and between smoking and nerve recovery were found. Results were better in nerves that were cut cleanly (64.3% were excellent/good) than in crushed nerves (28.1%). Without the availability of an operating microscope, loupes give a satisfactory result in nerve repair, and this study compares well with reported series.

Adolescent↗
PubMed1993

A critical review of the genotoxic potential of electric and magnetic fields.

55 published articles were identified which reported results of tests of ELF (extremely low frequency) or static electric or magnetic fields for genotoxic effects. The biological assays used spanned a wide range, including microbial systems, plants, Drosophila, mammalian and human cells in vitro and in vivo. Experimental results were grouped into four exposure categories: ELF Electric; ELF Magnetic; Static Electric; and Static Magnetic. The internal electric fields present in media (for in vitro experiments) and in the torso and extremities (for in vivo experiments) were estimated, providing an index of comparison. All experiments were critically analyzed with respect to basic data quality criteria. Experiments within each exposure category were then compared to determine if results reinforced or contradicted one another. The preponderance of evidence suggests that neither ELF nor static electric or magnetic fields have a clearly demonstrated potential to cause genotoxic effects. However, there may be genotoxic activity from exposure under conditions where phenomena auxiliary to an electric field, such as spark discharges, electrical shocks, or corona can occur. In addition, two unconfirmed reports suggest the genotoxic potential of certain chemical mutagens or ionizing radiation may be affected by co-exposure to electric or magnetic fields. Certain exposure categories are not represented or are under-represented by tests in some genotoxicity test systems that are usually included in minimal test batteries as specified by EPA for chemicals. It is suggested that consideration be given to whether additional genotoxicity testing is warranted to fill these gaps.

Animals↗
PubMed1993

Perianal injuries resulting from sexual abuse: a longitudinal study.

Four children who incurred perianal injuries as a result of a sexual assault were followed on a longitudinal basis to document the anatomical changes that ensued. The subjects, whose ages ranged from 4 to 8 years, were followed from 1 week to 14 months. They were examined in both supine and prone knee-chest positions and a 35-mm camera mounted on a colposcope was used to record their injuries. At the time of the initial examination, there were a variety of findings including erythema of the tissues, edema of the skin folds, localized venous engorgement, dilation of the external anal sphincter, and lacerations of different depths. Superficial lacerations reepithelized within 1 to 11 days. The second-degree wounds in two of the children were healed by the 1- and 5-week return visits, leaving narrow bands of scar tissue. In the two subjects who were followed the longest, signs of both a second-degree laceration and a surgically repaired third-degree injury had virtually disappeared by 12 to 14 months after the assaults. The wounds in one subject, infected with a herpes simplex type 2 virus, remained erythematous for a longer period of time than did similar injuries in the other children. A skin tag created by the avulsion of the tissues in one subject persisted, although it became less obvious as it retracted into the redundant folds of the perianal tissues over time.

Anal Canal↗
PubMed1992

Genital injuries resulting from sexual abuse: a longitudinal study.

Three children who incurred genital injuries as a result of sexual assaults were followed up on a longitudinal basis to document the anatomical changes which ensued. The subjects, who were 4 months, 4 years 5 months, and 9 years of age, were followed up for periods ranging from 14 months to 3 years. A multi-method examination approach and a 35-mm camera mounted on a colposcope were used to examine and record their injuries. Signs of the acute damage disappeared rapidly, and the wounds healed without complications. Following the resolution of the acute injuries, the changes created by the trauma remained relatively stable throughout the prepubertal years. The most persistent findings were irregular hymenal edges and narrow rims at the point of the injury. Over time the jagged, angular margins smoothed off. Disruption of the hymen exposed underlying longitudinal intravaginal ridges whose hymenal attachments created mounds or projections. There was little apparent scar formation. Even the injuries to the posterior fourchettes healed with minimal scar tissue and left only the slightest evidence of the trauma. With the onset of puberty, the hymenal changes in the oldest subject were obscured by the hypertrophy of this membrane. An examination technique which used a Q-tip to separate the redundant tissues demonstrated that the signs of trauma had survived.

Child↗
PubMed1991

Cognate interactions between helper T cells and B cells. V. Reconstitution of T helper cell function using purified plasma membranes from activated Th1 and Th2 T helper cells and lymphokines.

Th physically interact with B cells and produce lymphokines that influence B cell growth and differentiation. The respective contribution of cell contact and lymphokines to induction of B cell growth and differentiation was addressed using purified plasma membranes (PM) from resting Th (PMrest) and anti-CD3-activated Th (PMCD3) together with lymphokines. Results show that PMCD3, but not PMrest, induce 10% of resting B cells to enter the G1 phase of the cell cycle, with few B cells entering G1b and S/G2. The inclusion of IL-4, but not IL-2, IL-5, or IFN-gamma, amplifies the B cell response to PMCD3 by increasing the total percentage of activatable B cells to greater than 40% and inducing B cell progression into G1b, S, and G2. Direct comparison between PMrest and PMCD3 purified from Th1 and Th2 indicate that both Th1 and Th2 induce similar levels of B cell proliferation in the presence of IL-4. Further, the lymphokine requirements for B cell proliferation induced by PMCD3 from Th1 and Th2 is indistinguishable. B cell differentiation to IgM, IgG1, and IgG2a synthesis by PMCD3 required IL-4 and IL-5. Using lymphokine conditions that supported B cell differentiation, PMCD3 purified from Th1 and Th2 induced similar levels of IgM, and IgG1. Given the functional data on PMCD3 from Th1 and Th2, the data indicate that there are no substantive differences between Th1- and Th2-derived PMCD3, and that the major differences in the ability of viable Th1 and Th2 to activate B cells is the lymphokines produced by the cells.

Animals↗
PubMed1991

Driving and arthritis.

In a 3-year period, 94 patients with driving difficulties due to a variety of musculoskeletal disorders were assessed by the occupational therapy department of a rheumatology unit. The individual's ability to carry out each part of the driving process was recorded and the patients were classified into six broad categories. While some parts of the driving process often proved difficult, patterns of disability were found with different musculoskeletal disorders. Almost all of these difficulties could be overcome by simple modifications to vehicle or driving technique. Only one severely disabled individual required referral to a specialized mobility unit, while two individuals were found to be unsafe. Thus, almost all arthritic individuals are able to continue driving with the help of simple modifications. By providing an unsophisticated driving assessment service, a rheumatology unit can enable patients to continue driving and so maintain independence.

Arthritis↗
PubMed1990

Cognate interactions between helper T cells and B cells. IV. Requirements for the expression of effector phase activity by helper T cells.

After activation with anti-CD3, activated Th (THCD3), but not resting Th, fixed with paraformaldehyde induce B cell RNA synthesis when co-cultured with resting B cells. This activity is expressed by Th of both Th1 and Th2 subtypes, as well as a third Th clone that is not classified into either subtype. It is proposed that anti-CD3 activation of Th results in the expression of Th membrane proteins that trigger B cell cycle entry. Kinetic studies reveal that 4 to 8 h of activation with anti-CD3 is sufficient for ThCD3 to express B cell-activating function. However, activation of Th with anti-CD3 for extended periods of time results in reduced Th effector activity. Inhibition of Th RNA synthesis during the anti-CD3 activation period ablates the ability of ThCD3 to induce B cell cycle entry. This indicates that de novo synthesis of proteins is required for ThCD3 to express effector function. The ability of fixed ThCD3 to induce entry of B cell into cycle is not due to an increase in expression of CD3, CD4, LFA-1, ICAM-1, class I MHC or Thy-1. Other forms of Th activation (PMA and A23187, Con A) also induced Th effector function. Furthermore, purified plasma membranes from anti-CD3 activated, but not resting Th, induced resting B cells to enter cycle. The addition of IL-4, but not IL-2, IL-5, or IFN-gamma amplified the DNA synthetic response of B cells stimulated with PM from activated Th. Taken together these data indicate that de novo expression of Th surface proteins on activated Th is required for Th to induce B cell cycle entry into G1 and the addition of IL-4 is required for the heightened progression into S phase.

Animals↗
PubMed1990

Use of the colposcope in childhood sexual abuse examinations.

The addition of the colposcope to the armamentarium of the medical investigator of childhood sexual abuse has many advantages. The ability to accurately record anatomic findings has implications for the medical community, the judicial system, the accused, the victim, and the family. Through the use of the photographs produced by this instrument, examiners can inspect physical findings without the time constraints imposed by the short attention span of the young child. If necessary, colleagues can be consulted and interpretations discussed. The availability of these photographs to the courts has reduced the need to re-examine the child for another opinion. The colposcopic photograph has also proved to be an excellent teaching and research tool. As an aid to teaching, the photographs and slides produced by this instrument help the instructor demonstrate anatomic findings while allowing the student time to ask questions. As a research tool, this instrument has opened up a myriad of possibilities for medical examiners. It has facilitated the collection of clinical data, it has allowed the standardization of examination techniques, and with the help of computers it has made possible the sophisticated analysis of the information collected. The colposcope has limitations. Aside from its cost, it is a difficult instrument to use in the examination of the young child. The time required for an examination can increase substantially as the examiner attempts to maneuver the scope into a proper position. During this procedure, the maintenance of the child in a suitable state of relaxation, while avoiding further emotional trauma, can be a challenge. The reality that the photograph is two dimensional and represents only the findings at that moment will always be a limiting factor in its use as a means of assessing a child's anatomy. Even the multimethod approach employed to offset this problem may compound the situation by further increasing the length of the examination. Most of these and other dilemmas encountered in the use of the colposcope can be solved by additional experience with this instrument. Despite the improvements brought about by the introduction of the colposcope, more advanced technology may be needed to help solve some of the problems currently plaguing medical examiners. The use of video tape could provide a solution to the documentation of the changes that occur in the soft tissues as the child moves or becomes more or less relaxed. The potential of the computer appears unlimited, and its application to the problem of the interpretation of findings could make a significant contribution to the field.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗