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Biomedical subjects

Michael J Quinn

Publications and source records attributed to Michael J Quinn.

10 recordsLinked to original sources
PubMed2006

Reproductive toxicity of trenbolone acetate in embryonically exposed Japanese quail.

This study was conducted to assess the effects of a one time embryonic exposure to trenbolone acetate on reproductive development and function in Japanese quail (Coturnix japonica). Embryos were exposed to either 0.05, 0.5, 5, or 50microg trenbolone or a sesame oil vehicle control at embryonic day 4. Onset of puberty, gonadal histopathology, sperm motility, cloacal gland size, and male copulatory behavior were assessed in adults. Trenbolone delayed onset of puberty in males, inhibited cloacal gland development, and reduced male reproductive behaviors. Industry laboratories have shown trenbolone acetate to be non-teratogenic in mammalian studies. Our study, however, shows that this one time in ovo exposure delayed onset of puberty in and suppressed adult copulatory behavior in quail males. These results suggest that this one time embryonic exposure to trenbolone may have disrupted development of either the central nervous system or the hypothalamic-pituitary-gonadal axis. This is the first study to demonstrate a demasculinizing effect on copulatory behavior in Japanese quail from embryonic exposure to a non-aromatizable androgenic chemical. More studies are needed to determine the mechanisms behind the observed effects.

Animals↗
PubMed2006

On teaching computer ethics within a computer science department.

The author has surveyed a quarter of the accredited undergraduate computer science programs in the United States. More than half of these programs offer a 'social and ethical implications of computing' course taught by a computer science faculty member, and there appears to be a trend toward teaching ethics classes within computer science departments. Although the decision to create an 'in house' computer ethics course may sometimes be a pragmatic response to pressure from the accreditation agency, this paper argues that teaching ethics within a computer science department can provide students and faculty members with numerous benefits. The paper lists topics that can be covered in a computer ethics course and offers some practical suggestions for making the course successful.

Computers↗
PubMed2006

Effects of androgen disruption by DDE on the development and functioning of the immune system in Japanese quail.

We hypothesized that immunosuppression in birds that is caused by exposure to antiandrogenic chemicals occurs mainly through disruption of the development of the androgen-sensitive avian lymphoid organ, the bursa of Fabricius. Injections of 20.0 or 40.0 mug of p,p'-DDE [ethylene, 1,1-dichloro-2,2-bis(p-chlorophenyl)], an antiandrogen, were administered at embryonic day 1. Bursas from only chicks treated with DDE were larger than, had fewer follicles, and exhibited vacuolization within follicles compared with controls; spleens were unaffected. No differences in either immune response test were observed. This study demonstrates that the bursa may play a role in androgen-active endocrine disrupting chemical-induced immunosuppression.

Androgen Antagonists↗
PubMed2005

Fluctuating asymmetry and growth as biomarkers for exposure to androgen disrupting chemicals in Japanese quail.

The effects of embryonic exposure to androgen disrupting chemicals (ADCs) on growth and fluctuating asymmetry (FA) were determined in Japanese quail chicks. Embryos were exposed to an anti-androgenic chemical, 1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane (p,p'-DDE) at 20 or 40 microg, or to an androgenic chemical, trenbolone acetate, at 5 or 50 microg on day one of incubation. Growth was measured by body weight and tarsus and culmen lengths from day of hatch until day 29. FA was measured as differences in right versus left lengths of the tarsus, radius, zygomatic process, and premaxilla in day old carcasses. No differences in FA were observed for either treatment. Embryonic exposure to DDE resulted in no significant differences in all measures of growth, although the same quail exhibited significant differences in immunological, reproductive, and behavioral measurements (reported elsewhere). Chicks exposed to trenbolone exhibited no differences in body weight or measures of FA at day of hatch, however, subsequent growth was inhibited. This study shows that although growth and FA are often used as measures of chemical stress experienced during embryonic development, they are not sensitive measures for exposure to these ADCs at these levels in Japanese quail.

Androgen Antagonists↗
PubMed2005

Outcome in 846 cutaneous melanoma patients from a single center after a negative sentinel node biopsy.

BACKGROUND: A negative sentinel node biopsy (SNB) implies a good prognosis for melanoma patients. The purpose of this study was to determine the long-term outcome for melanoma patients with a negative SNB. METHODS: Survival and prognostic factors were analyzed for 836 SNB-negative patients. All patients with a node field recurrence were reviewed, and sentinel node (SN) tissue was reexamined. RESULTS: The median tumor thickness was 1.7 mm, and 23.8% were ulcerated. The median follow-up was 42.1 months. Melanoma specific survival at 5 years was 90%, compared with 56% for SN-positive patients (P < .001). On multivariate analysis, only thickness and ulceration retained significance for disease-free and disease-specific survival. Five-year survival for patients with nonulcerated lesions was 94% vs. 78% with ulceration. Eighty-three patients (9.9%) had a recurrence. Twenty-seven patients developed recurrence in the regional node field, and in 22 of these, it was the first recurrence site. Six developed local recurrence, 17 an in-transit metastasis, and 58 distant disease. The false-negative rate was 13.2%. SN slides and tissue blocks were further examined in 18 patients with recurrence in the node field, and metastatic disease was found in 3 of them. CONCLUSIONS: This large, single-center study confirms that patients with a negative SNB have a significantly better prognosis than those with positive SNs. In those with a negative SNB, primary tumor thickness and ulceration are independent predictors of survival. Incorrect pathologic diagnosis contributed to only a minority of the false-negative results in this study.

False Negative Reactions↗
PubMed2005

Treatment of metastatic melanoma using electroporation therapy with bleomycin (electrochemotherapy).

Electroporation therapy (EPT) is a novel treatment modality that uses brief, high-intensity, pulsed electrical currents to enhance the uptake of chemotherapeutic agents, vaccines and genes into cells. This technique is potentially useful for patients with secondary and, possibly, some primary tumours. Nineteen patients with metastatic melanoma were enrolled in a phase two, randomized, open-label study comparing intralesional bleomycin+EPT with intralesional bleomycin alone. Of 18 study lesions, 13 (72%) showed a complete response, one (5%) showed a partial response, three (18%) showed no change and one (5%) showed disease progression over a period of greater than 12 weeks. This represents a 78% objective response rate, which was significantly greater than the 32% response rate observed in the 19 patients with tumours treated with intralesional bleomycin alone (chi=7.94, 1 df, P=0.005). An additional 36 lesions, not enrolled in the study, were also treated with bleomycin+EPT. Of the total of 54 lesions treated with bleomycin+EPT, there was a 72% objective response rate. EPT treatment was well tolerated and was performed on an outpatient basis.

Adult↗
PubMed2004

Ultrasound examination of sentinel nodes in the initial assessment of patients with primary cutaneous melanoma.

BACKGROUND: The value of targeted high-resolution ultrasound (US) examination in detecting sentinel lymph node metastases in patients with newly diagnosed primary cutaneous melanomas has not yet been fully evaluated. The aim of this study was to determine the threshold size of metastatic melanoma deposits in SLNs able to be detected by targeted US examination before initial melanoma surgery. METHODS: A total of 304 patients presenting with primary cutaneous melanomas had SLNs identified by lymphoscintigraphy and then examined in situ by the same physician with high-resolution US. Within 24 hours, the SLNs were removed for histopathologic assessment of sections stained conventionally and with immunohistochemical markers for S100 protein and HMB45 antigen. RESULTS: Metastatic disease was present in SLNs from 33 node fields in 31 patients. The US results in seven of these cases were suggestive of metastatic disease. Twenty-six node fields contained positive nodes not detected by US. Undetected deposits had diameters <4.5 mm. CONCLUSIONS: These results suggest that a targeted US examination of SLNs can detect metastatic melanoma deposits down to approximately 4.5 mm in diameter. However, most metastatic melanoma deposits in SLNs are considerably smaller than this at the time of initial staging, and US therefore cannot be considered cost-effective in this setting.

Adolescent↗
PubMed2004

Correlation between preoperative lymphoscintigraphy and metastatic nodal disease sites in 362 patients with cutaneous melanomas of the head and neck.

OBJECTIVE: Lymphoscintigraphy for head and neck melanomas demonstrates a wide variation in lymphatic drainage pathways, and sentinel nodes (SNs) are reported in sites that are not clinically predicted (discordant). To assess the clinical relevance of these discordant node fields, the lymphoscintigrams of patients with head and neck melanomas were analyzed and correlated with the sites of metastatic nodal disease. METHODS: In 362 patients with head and neck melanomas who underwent lymphoscintigraphy, the locations of the SNs were compared with the locations of the primary tumors. The SNs were removed and examined in 136 patients and an elective or therapeutic regional lymph node dissection was performed in 40 patients. RESULTS: Lymphoscintigraphy identified a total of 918 SNs (mean 2.5 per patient). One or more SNs was located in a discordant site in 114 patients (31.5%). Lymph node metastases developed in 16 patients with nonoperated SNs, all underneath the tattoo spots on the skin used to mark the position of the SNs. In 14 patients SN biopsy revealed metastatic melanoma. After a negative SN biopsy procedure 11 patients developed regional lymph node metastases during follow-up. Elective and therapeutic neck dissections demonstrated 10 patients with nodal metastases, all located in predicted node fields. Of the 51 patients with involved lymph nodes, 7 had positive nodes in discordant sites (13.7%). CONCLUSIONS: Metastases from head and neck melanomas can occur in any SN demonstrated by lymphoscintigraphy. SNs in discordant as well as predicted node fields should be removed and examined to optimize the accuracy of staging.

Head and Neck Neoplasms↗
PubMed2002

The effects of polychlorinated biphenyls (Aroclor 1242) on thyroxine, estradiol, molt, and plumage characteristics in the American kestrel (Falco sparverius).

The purpose of this experiment was to determine the effects of Aroclor 1242, a mixture of polychlorinated biphenyls (PCBs), on plumage characteristics and molt in the American kestrel, Falco sparverius. Several characteristics of plumage, including color and molt schedule, are modulated by hormonal signals and hence may be modified by endocrine-active contaminants. If so, the functions of plumage (e.g., communication for mating or territorial defense) may be compromised by exposure to such compounds. Captive American kestrels were fed Aroclor 1242 at 0, 6.0, and 60.0 ppm (n = 6 males and 6 females per treatment) mixed in their normal diet. Concentrations of plasma estradiol and thyroxine were measured weekly from the beginning of treatment. Measured plumage characteristics included width of the black subterminal band on the tail, color (a composite index of hue and saturation), reflectance from 230 to 800 nm. pattern of feather loss and regrowth on the tail and wing, and timing of onset and duration of molt. Aroclor 1242 depressed plasma thyroxine. Plasma estradiol levels remained low due to the phase of the breeding cycle. Treatments did not disrupt the measured plumage characteristics. This may be due to timing or dose of exposure or to genetic factors.

Administration, Oral↗