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Biomedical subjects

J McCann

Publications and source records attributed to J McCann.

At least 127 records · Page 7Linked to original sources
PubMed1990

Nail re-growth in fingertip injuries.

One hundred and fifty-five fingertip injuries were treated over a one-year period. Seventy-six patients with 90 fingertip injuries attended for follow-up. Sixty-four of these injuries were suitable for study. In ten cases, the nail was either trimmed and left in-situ, or cleaned and replaced (Group A). In the remaining 54 cases, the nail was either missing, or had been removed at operation (Group B). The two groups were compared in terms of nail re-growth and nail appearance, but no statistically significant difference was found. There was a direct correlation between final outcome and the degree of crush injury. We conclude that it is the severity of the original injury and the accuracy of the primary repair of the nailbed which are the main determinants of the outcome of a nailbed injury. Non-replacement of the nail did not appear to adversely affect nail re-growth and nail appearance.

Adolescent↗
PubMed1990

Comparison of genital examination techniques in prepubertal girls.

The results of three separate methods used to examine prepubertal girls are compared and a technique for measuring hymenal orifice diameters from colposcopic photographs is presented. A total of 172 girls who were examined by three techniques during their evaluation in a clinic for suspected child sexual abuse victims were studied. Their ages ranged from 10 months to 11 years with a mean of 5 years, 8 months. The examination techniques used were the supine position with labial separation, the supine position with labial traction, and the knee-chest position. The knee-chest position (98%) and the supine traction method (96%) proved to be superior to the supine separation technique (86%) in opening the vaginal introitus. The largest vertical transhymenal diameters were produced in the knee-chest position, whereas the greatest transverse horizontal spans were generated by the supine traction procedure. Other soft tissue changes were noted but not quantified. A multimethod approach to the examination of the sexually abused child is recommended to take advantage of the strengths of each technique.

Child↗
PubMed1990

Genital findings in prepubertal girls selected for nonabuse: a descriptive study.

This project was designed to collect normative data on the genital anatomy from a sample of nonabused prepubertal girls. A total of 114 girls between the ages of 10 months and 10 years were examined and photographed with a colposcope. After screening for the onset of puberty and the possibility of undetected abuse, 93 subjects remained. Examination techniques included a supine labial separation approach, a supine labial traction method, and a prone knee-chest position. Common genital finding included erythema of the vestibule (56%), periurethral bands (50.6%), labial adhesions (38.9%), lymphoid follicles on the fossa navicularis (33.7%), posterior fourchette midline avascular areas (25.6%), and urethral dilation with labial traction (14.9%). The hymenal orifice opened more frequently during the knee-chest (95.2%) and the labial traction (90.5%) methods than with the supine separation (79.3%) approach. Hymenal findings included mounds (33.8%), projections (33.3%), and "septal remnants"/midline hymenal tags (18.5%). Intravaginal findings of vaginal ridges (90.2%) and rugae (88.7%) were found primarily through the labial traction approach. The cervix was visualized without the use of speculum in 69% of the children during the knee-chest examination. Unusual findings included posterior fourchette friability (4.7%), anterior hymenal clefts (1.2%), and notches of the hymen (6%). One child had an imperforate hymen (1.2%) and 2 (2.5%) had hymenal septa. A vaginal discharge was detected in 2 (2.6%) and a foreign body in 1 (1.3%). Tables that include the vertical and horizontal hymenal orifice diameters by age group and by method are presented.

Child↗
PubMed1989

Cognate interactions between helper T cells and B cells. II. Dissection of cognate help by using a class II-restricted, antigen-specific, IL-2-dependent helper T cell clone.

In order to determine the involvement of T-B cell contact vs lymphokine production in mediating B cell cycle entry and progression, Th cell clones "defective" in lymphokine production were cloned. Th-3.1 is one such clone that required IL-2 to produce significant levels of IL-4 and IFN-gamma. Unlike conventional Th clones, Th-3.1 induced B cell proliferation only in the presence of Ag and IL-2. In contrast to the absolute requirement of IL-2 for Th-3.1-induced B cell proliferation, IL-2 was not required for the formation of stable Th-3.1-B cell conjugates or Th-3.1-induced B cell entry into the G1 phase of the cell cycle. In the absence of IL-2 and under conditions that promoted Th-B cell interactions, Th-3.1 induced 10 to 20% of resting B cells to enter G1. B cell entry into the cell cycle was not inhibited by anti-lymphokine mAb or promoted by exogenous lymphokines, suggesting that endogenous lymphokine activity was not required for Th-3.1-induced G0 to G1 transition. The data suggested that the IL-2-independent induction of B cells into G1 by Th-3.1 was a cell contact-dependent event. Direct proof that Th-3.1-B cell contact was necessary for B cell cycle entry was provided by comparative in situ analysis of the RNA synthetic activity and the RNA content of B cells that were in physical contact with Th-3.1 or not in contact with Th-3.1. In situ autoradiography of RNA synthesis illustrated that a high frequency of B cells in contact with Th-3.1 expressed heightened RNA synthetic activity, whereas "bystander" B cells were less frequently induced into cycle. In situ laser cytometry of B cell size and total RNA content showed that B cells in physical contact with Th-3.1 had a higher RNA content and were larger than "bystander" B cells present in the same microcultures. This model system has allowed the dissection of T cell help into IL-2-dependent and IL-2-independent phases. Early cell contact-dependent events and B cell cycle progression into G1 were IL-2 independent, whereas the production of lymphokines (IL-4, IFN-gamma) by Th-3.1 and Th-3.1-induced B cell proliferation was IL-2 dependent.

Animals↗
PubMed1989

Cognate interactions between helper T cells and B cells. III. Contact-dependent, lymphokine-independent induction of B cell cycle entry by activated helper T cells.

An Ag-specific, IL-2-dependent Th clone induced the growth of B cells in a class II-restricted, Ag-specific, IL-2-dependent manner. The formation of stable Th-3.1-B cell conjugates was restricted by Ag and class II MHC. After activation of Th-3.1 by insolubilized anti-T3 (Th-3.1T3), Th-3.1T3 induced the growth of B cells in a class II unrestricted, Ag nonspecific manner. The formation of stable conjugates between Th-3.1T3 and B cells was also class II unrestricted and Ag nonspecific. Although the interaction of Th-3.1T3 and B cells was class II unrestricted, the interaction was inhibited by the combination of anti-IA and anti-IE mAb. This suggested that monomorphic domains of class II MHC molecules were involved in Th-3.1T3-B cell interaction. Fixed Th-3.1T3 but not fixed resting Th-3.1 induced B cell cycle entry, as measured by an increase in B cell RNA synthesis. Trypsin-treatment of Th-3.1T3 before fixation reduced their ability to activate B cells, indicating that cell surface proteins on Th-3.1T3 were required for enhanced B cell RNA synthesis. Anti-IL-4, anti-IL-2R, or anti-IFN-gamma did not affect the ability of Th-3.1T3 to induce heightened B cell RNA synthesis. Progression into S phase by B cells activated with fixed Th-3.1T3 was supported by the addition of soluble factors. When stimulated with fixed Th-3.1T3, EL4 supernatant (SN) enhanced B cell DNA synthesis. Depletion of IL-4, but not IL-2, from EL4 SN ablated its supportive capabilities. IL-4 alone was completely ineffective in supporting entry into S phase. Therefore, IL-4 and another activity(ies) in EL4 SN were necessary for B cell cycle progression into S phase. Taken together, these data suggest that after Th activation, Th cell surface proteins are expressed that mediate the binding of Th to B cells via recognition of nonpolymorphic domains of class II MHC molecules. Contact of Th-3.1T3 with B cells, not lymphokines, results in the entry of B cells into the cell cycle and heightened B cell lymphokine responsiveness. The addition of exogenous lymphokines supports the progression of Th-3.1T3-activated B cells into S phase.

Animals↗
PubMed1989

Perianal findings in prepubertal children selected for nonabuse: a descriptive study.

The results of the perianal portion of a project designed to collect normative data of the anogenital anatomy from a representative sample of prepubertal children is presented. A total of 318 children were examined by three physicians from a child sexual abuse evaluation program. After screening for the onset of puberty and the possibility of undetected abuse, 267 subjects remained. The sample included 161 girls and 106 boys ranging in age from 2 months to 11 years. The perianal findings that were encountered with the greatest frequency included erythema (41%), increased pigmentation (30%), and venous engorgement (52%) after two minutes in the knee-chest position. Wedge-shaped smooth areas in the midline, with or without depressions, were found both anterior and posterior to the anus in 26% of the children. Anal skin tags/folds were discovered anterior to the anus in 11%. In 49% of the children there was some dilatation of the anus which opened and closed intermittently in 62%. Flattening of the anal verge and rugae occurred during dilatation by the midpoint of the examination in 44% and 34%, respectively. Perianal findings that were found infrequently in all subgroups included skin tags/folds (0%) and scars (1%) outside the midline, anal dilatation greater than 20 mm without the presence of stool in the rectal ampulla (1.2%), irregularity of the anal orifice after complete dilatation (3%), and prominence of the anal verge (3%). No abrasions, hematomas, fissures, or hemorrhoids were encountered. Less commonly detected findings within specific subgroups included perianal erythema in girls (32%) as compared to boys (57%), pigmentation in the lighter skinned white children (22%) when compared to black (53%) and Hispanic (58%) children, and venous congestion at the beginning of the examination (7%) when compared to the same findings after four minutes in the knee-chest position (73%). There were no perianal skin tags/folds found in the boys. The relatively high incidence of perianal soft tissue changes that were found in this study, when compared to the frequency of similar observations in children suspected of having been sexually abused, reemphasizes the caution medical examiners must exercise in rendering an opinion as to the significance of medical findings.

Anal Canal↗
PubMed1989

Paedophilia and hyperprolactinaemia.

The case of a man presenting with paedophilia who has found to be hyperprolactinaemic is described. There is possibly a link between paedophilia and endocrine disorders.

Adult↗
PubMed1989

Cognate interactions between helper T cells and B cells. I. Cloning and helper activity of a lymphokine-dependent helper T cell clone (Th-3).

Two essential events in the development of humoral immune responses to thymus-dependent (TD) antigens are the physical interaction of helper T cells (Th) with B cells and the elaboration of Th-derived lymphokines. Understanding the respective contribution of Th-B cell contact vs. lymphokines in triggering B-cell growth and differentiation has been hindered by the capacity of most Th clones to provide both cell contact-dependent and lymphokine-dependent signals. Our approach to study the role of lymphokines in TD B-cell growth and differentiation was to select antigen-specific Th clones that were able to induce class II-restricted B-cell growth and differentiation only in the presence of exogenously added lymphokines. In such a way, selected Th clones would putatively be defective in lymphokine production, but able to provide cell contact-dependent signals. One clone selected in this manner, Th-3.1, has been instrumental in addressing the role of IL4 in TD B-cell responses. Upon co-culture of purified TNP-specific B cells (TNP-ABC), antigen, and Th-3.1, Th-3.1 was unable to induce TNP-ABC growth or differentiation unless an exogenous lymphokine source (EL4 SN) was provided. The reason for the exogenous lymphokine requirement was two-fold. First, it appeared that Th-3.1 required IL2 to produce lymphokines (IL4) essential for B-cell growth and differentiation. Second, even in the presence of antigen and IL2, the level of lymphokine production by Th-3.1 was insufficient to induce optimal B-cell responses. Because an exogenous source of lymphokines was essential for Th-3.1-induced TNP-ABC growth and differentiation, the requirement for specific lymphokines in TD B-cell responses could be addressed. One lymphokine shown to be necessary for Th-3.1-induced TNP-ABC growth and differentiation was IL4. Addition of anti-IL4 to culture or the depletion of IL4 from the exogenous lymphokine source reduced the TD proliferative and antibody response of TNP-ABC. Because the addition of IL4 alone was unable to restore helper activity, it was concluded that IL4 was necessary but not sufficient for TD B-cell growth and differentiation. Pre-incubation of TNP-ABC and IL4 overcame the IL4 requirement when co-cultured with Th-3.1 and antigen.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1989

Longitudinal analysis of hope in community-based older adults.

Clinicians usually agree that hope helps older persons to cope with stressful life events and changes in their life, and that hope may even affect their health. However, little research has examined whether hope functions as a psychosocial factor in modifying the relationship between stress and health. Older adults experience many events, which may make them more vulnerable than younger persons to loss of hope. These events may involve changes in their health, roles, self-concept, social support, housing, and income. If we know how these events affect hope, we may be able to detect and avert lapses in hope among our older patients, and even shape interventions that enhance hope.

Adaptation, Psychological↗
PubMed1989

Changes in collagen biosynthesis, types, and mechanics of aorta in hypertensive rats.

The purpose of this study was to relate changes in collagen composition with the mechanical properties of aortas of spontaneously hypertensive rats (SHRs). SHRs and normal Wistar-Kyoto (WKY) rats were killed at ages 6 and 20 weeks, and their aortas were removed. A portion of each aorta was used for determination of passive mechanical properties, and the remainder was incubated with carbon 14-labeled proline containing medium for 18 hours at 37 degrees C. After incubation, the tissues were lyophilized, and aliquots were used for sequential extraction with neutral salt, acetic acid, and pepsin at 4 degrees C. The pepsin extracts that contained most of the collagen were used for characterization of the collagen types and synthesis of collagen by the production of [14C]-labeled hydroxyproline. Collagen concentration decreased approximately 16% in both 6- and 20-week-old aortas, but collagen synthesis was about twofold higher in the aortas from both 6- and 20-week-old SHRs. Although type V collagen represented a minor fraction of total collagen (5%) in the aortas of WKY rats, it was twofold greater in the hypertensive animals. This increment in type V collagen in SHR aortas was accompanied by a reduction in the proportion of type I collagen, with no change in the proportion of type III. Study of the passive mechanical properties of the tissues showed that SHR aortas were stiffer compared with aortas of WKY rats, with a larger difference at 20 weeks than at 6 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1988

Labial adhesions and posterior fourchette injuries in childhood sexual abuse.

Six cases involving six sisters, all of whom were sexually molested, are presented to illustrate the association between labial adhesions and posterior fourchette injuries in sexually abused children. Although labial adhesions are a relatively common lesion, they only recently have been associated with childhood sexual abuse. Labial adhesions are ordinarily found in girls between 2 months and 7 years of age and are usually very superficial and disappear spontaneously by the time the child approaches puberty. We encountered six sisters, all of whom had been sexually abused, who had labial adhesions. Four of the six had changes in the area of the posterior fourchette that were consistent with previous trauma. In addition, four of the girls' hymens had thickened, irregular edges or other changes that were considered abnormal. The father, the grandfather, and an uncle confessed to lewd and lascivious misconduct with the children. Although labial adhesions alone are not reason enough to make a report of sexual abuse, the physician is obligated to inquire as to the possible cause if the adhesions do not fit the usual pattern or if there are other suspicious findings.

Child↗
PubMed1987

Effect of trimethoprim on serum creatinine in healthy and chronic renal failure volunteers.

The effect of trimethoprim (TMP) on serum creatinine concentration (SCr) was studied in 10 healthy (H) subjects and nine subjects with chronic renal failure (CRF). Each volunteer was given TMP 100 mg perorally every 12 h for 10 days followed by a 7-day washout period. SCr was measured colorimetrically immediately before the study (baseline), on day 10 of TMP, and 7 days after TMP had been discontinued. SCr increased an average of 14.8% from baseline during TMP administration in the H volunteers, but this increase was not statistically significant. During TMP administration to the CRF volunteers, a pronounced elevation (34.6%) of mean SCr from baseline was observed (p less than 0.05). SCr returned to baseline values in both groups following the 7-day washout period. These results are consistent with the hypothesis that TMP competitively inhibits the renal tubular secretion of creatinine.

Adult↗
PubMed1986

The Salmonella typhimurium/mammalian microsomal assay. A report of the U.S. Environmental Protection Agency Gene-Tox Program.

The Salmonella assay has been in use for almost 15 years and can be defined as a routine test for mutagenicity and for predicting potential carcinogenicity. It detects the majority of animal carcinogens and consequently plays an important role in safety assessment. The test is also routinely used as the frontline screen for environmental samples (complex mixtures) isolated from air, water and food. This role will continue to remain an area of growth as or because sample volumes associated with these testing areas are generally very limited and more extensive testing is generally impossible. While this test, like all others, has some limitations, it is recommended that it be regularly included in all genetic testing batteries.

Animals↗
PubMed1984

An evaluation of Salmonella (Ames) test data in the published literature: application of statistical procedures and analysis of mutagenic potency.

We searched the published literature for Salmonella test data on some 450 chemicals. Only 137 of more than 400 articles containing original data satisfied minimum criteria for a quantitative analysis [1751 experiments, comprising data on 152 chemicals (Table 1)]. Many of these papers did not report basic information about the test protocol (Table 2). We used previously described statistical procedures (Bernstein et al., 1982) to estimate the initial slopes of the dose-response curves and corresponding standard errors. We also applied tests for significance and linear goodness-of-fit. We then used the results of these analyses to examine several issues: (1) Linearity of the low dose region of the dose-response curve. We found that the overwhelming majority of curves were linear, though ability to detect non-linearity of dose-response curves in the standard plate test is only limited. 7% of all experiments to which the goodness-of-fit test was applied were curves of increasing slope, and with a few possible exceptions, these were not obviously associated with any particular mutagens, even those generally considered to produce non-linear effects such as MNNG and EMS (Table 3). (2) Performance of the statistical test for significance. Results of the statistical test for significance of the dose-response were compared with author's opinions as to positivity. In almost all cases (94%) results of the statistical test and authors opinions were the same. In the examples of conflicting opinions, the reasons were: (a) the statistical test places more weight than do most authors on the presence of a linear dose-response; (b) most authors tend to require at least a 2-fold increase over the spontaneous background for 'significance', and (c) when the number of spontaneous revertants is small (e.g., TA1537), authors tend to require a larger increase in induced revertants than when the spontaneous background is large, whereas the statistical procedure makes no such distinction. These factors result in the statistical test tending to identify more experiments as positive than do authors, provided there is a linear dose-response, and authors tending to judge more experiments as positive when the dose-response is not linear. (3) Reproducibility. Among the 1751 experiments there were 122 data-sets (a total of 333 experiments) in which the same chemical was tested by two or more different laboratories under the same protocol. 21 of the 122 data-sets had some disagreement between experiments as to whether results were positive or negative (Table 4).(ABSTRACT TRUNCATED AT 400 WORDS)

Dose-Response Relationship, Drug↗