Search PubMed⌕ Search

Biomedical subjects

K T Kavanagh

Publications and source records attributed to K T Kavanagh.

At least 19 recordsLinked to original sources
PubMed2001

Green tea extracts decrease carcinogen-induced mammary tumor burden in rats and rate of breast cancer cell proliferation in culture.

Epidemiological evidence suggests tea (Camellia sinensis L.) has chemopreventive effects against various tumors. Green tea contains many polyphenols, including epigallocatechin-3 gallate (EGCG), which possess anti-oxidant qualities. Reduction of chemically induced mammary gland carcinogenesis by green tea in a carcinogen-induced rat model has been suggested previously, but the results reported were not statistically significant. Here we have tested the effects of green tea on mammary tumorigenesis using the 7,12-dimethylbenz(a)anthracene (DMBA) Sprague-Dawley (S-D) rat model. We report that green tea significantly increased mean latency to first tumor, and reduced tumor burden and number of invasive tumors per tumor-bearing animal; although, it did not affect tumor number in the female rats. Furthermore, we show that proliferation and/or viability of cultured Hs578T and MDA-MB-231 estrogen receptor-negative breast cancer cell lines was reduced by EGCG treatment. Similar negative effects on proliferation were observed with the DMBA-transformed D3-1 cell line. Growth inhibition of Hs578T cells correlated with induction of p27(Kip1) cyclin-dependent kinase inhibitor (CKI) expression. Hs578T cells expressing elevated levels of p27(Kip1) protein due to stable ectopic expression displayed increased G1 arrest. Thus, green tea had significant chemopreventive effects on carcinogen-induced mammary tumorigenesis in female S-D rats. In culture, inhibition of human breast cancer cell proliferation by EGCG was mediated in part via induction of the p27(Kip1) CKI.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1999

The inhibitory effects of transforming growth factor beta1 on breast cancer cell proliferation are mediated through regulation of aberrant nuclear factor-kappaB/Rel expression.

Nuclear factor (NF)-kappaB/Rel transcription factors normally exist in non-B cells, such as epithelial cells, in inactive forms sequestered in the cytoplasm with specific inhibitory proteins, termed IkappaBs. Recently, however, we discovered that breast cancer is typified by aberrant constitutive expression of NF-kappaB/Rel factors. Because these factors control genes that regulate cell proliferation, here we analyzed the potential role of NF-kappaB/Rel in the ability of transforming growth factor (TGF)-beta1 to inhibit the growth of breast cancer cells. The decreased growth of Hs578T and MCF7 breast cancer cell lines on TGF-beta1 treatment correlated with a drop in NF-kappaB/Rel binding. This decrease was due to the stabilization of the inhibitory protein IKB-alpha. Ectopic expression of c-Rel in Hs578T cells led to the maintenance of NF-kappaB/Rel binding and resistance to TGF-beta1-mediated inhibition of proliferation. Similarly, expression of the p65 subunit ablated the inhibition of Hs578T cell growth mediated by TGF-beta1. Thus, the inhibition of the aberrantly activated, constitutive NF-kappaB/Rel plays an important role in the arrest of the proliferation of breast cancer cells, which suggests that NF-kappaB/Rel may be a useful target in the treatment of breast cancer.

Animals↗
PubMed1994

Applications of image-directed robotics in otolaryngologic surgery.

This report will evaluate the feasibility of applying image-directed robotic technology to the field of otolaryngologic surgery. Image-directed robotic surgery uses a three-dimensional image to guide a robot in the removal of tissue. To demonstrate the future use of image-directed robotics in otolaryngologic surgery, five antrostomies will be performed on temporal bones. The accuracy of the surgical defect will be measured. It is the goal of this pilot study to achieve an average surgical error of less than 1.0 mm. Future applications of image-directed robotic surgery will be presented, along with technical modifications, and future areas of research necessary to adapt this technique to otology and rhinosinus surgery.

Equipment Design↗
PubMed1992

Airway obstruction in the mentally handicapped.

We have presented a case of laryngomalacia in an 18-year-old mentally retarded woman treated with epiglottoplasty. The preoperative and postoperative appearance of the larynx during aspiration was documented using video and still photography. Diagnosis was made by fiberoptic nasopharyngoscopy and laryngoscopy.

Adolescent↗
PubMed1992

Passive exposure to cocaine in medical personnel and its effect on urine drug screening tests.

This report studies the importance of passive exposure of medical personnel to cocaine hydrochloride and its impact on urine screening testing. Eleven medical staff members were exposed to cocaine hydrochloride by means of aerosol and cutaneous application, similar to that which may occur in medical practice. Urine drug screening tests were negative for everyone tested. This finding is supported by known drug kinetics. It is unlikely that a single passive exposure of medical staff to cocaine hydrochloride will produce a positive urine screening test. In all cases of positive urine tests, contaminants should be tested for which may indicate a source of the drug. The routine use of gloves and masks--which is recommended to prevent HIV infection--should further decrease medical personnel's passive exposure to cocaine hydrochloride.

Administration, Cutaneous↗
PubMed1992

Evaluation of occupational hearing loss and presbyacusis using a microcomputer.

Occupational noise-induced hearing loss remains a common problem in industry. This report presents a systematic method of patient evaluation and describes software that is capable of calculating hearing handicaps from audiometric data and the proportion of the handicap due to presbyacusis. The software also has the capability of subtracting the effects of presbyacusis from the current audiometric thresholds and to estimate hearing thresholds at any future age of the patient. Four patients are presented that illustrate the utility of this type of computer analysis.

Adult↗
PubMed1991

Fungal sinusitis in immunocompromised children with neoplasms.

This paper reviews the treatment and diagnosis of immunocompromised patients with fungal sinusitis at St Jude Children's Research Hospital. Sinusitis of all types was found to be more common in patients with hematopoietic neoplasms than in patients with solid tumors; 42% of patients with leukemia had abnormal sinus radiographs. Eight cases of pathologically proven fungal sinusitis were identified. All patients were undergoing chemotherapy for either acute myeloblastic leukemia or acute lymphoblastic leukemia and had neutrophil counts less than 100 cells/mm3. The most common findings were fever, facial pain, and abnormal sinus radiographs. Surveillance cultures of the upper aerodigestive system did not reliably predict sinus pathogens. An aggressive treatment approach consisting of early administration of amphotericin B (intravenously and via catheter irrigations of the sinuses) and surgical drainage is advocated. There was an 80% survival rate in patients in remission who were undergoing maintenance chemotherapy. All patients undergoing chemotherapy for relapse died.

Aspergillosis↗
PubMed1991

Multivariate analysis of family risk factors in predicting appointment attendance in a pediatric otology and communication clinic.

Parents of pediatric patients attending regional otologic medical clinics were given a questionnaire to document family risk factors predictive of poor appointment attendance, and to determine barriers which caused non-attendance of medical appointments. Family risk factors which affected clinic attendance were studied using univariate and multivariate analyses. Univariate analyses revealed all factors except patients' sex and family size to be correlated with attendance. However, multivariate analysis revealed that parental age (p less than 0.0153), ownership of car (p less than 0.0012), parental education (p less than 0.0048), and age of patient (p less than 0.0023) were major predictors of clinic attendance. Although ownership of a car was a major independent factor, it was highly correlated with parental age and parental education and only shown to be significant in the subset of patients not having access to public transportation. The identified parental factors which affect pediatric health care delivery underscores the importance of family centered case management in promoting the health care of children and casts doubt on the effectiveness of interventions which are solely centered on the patient or are designed to mitigate only one of these factors.

Adult↗
PubMed1990

Models to promote medical health care delivery for indigent families: computerized tracking to case management.

Poor patient/parental medical compliance is one of the most important health care issues of today. Multiple interrelated factors contribute to this problem. Of prime importance is patient/parental maturity and knowledge. Reversal of this process is undoubtably harder than prevention. The cost effectiveness of various methods of intervention is discussed in relation to a large mid-south indigent population. Computerized patient tracking is cost efficient and effectively promotes compliance in a percentage of patients. Its additional utility is the identification and triage of patients, most in need of intervention, to existing social service personnel for family-centered case management. Family-centered case management holds the best hope of reversing the many factors adversely affecting patient compliance. However, this method is costly and requires a low ratio of clients to caseworkers in order to be effective. Community-centered patient management is less costly to implement and is very useful in tightly woven communities resistant to outside intervention. However, this method often has a high client to caseworker ratio and has less utility in dealing with complex medical problems.

Adolescent↗
PubMed1989

Michel dysplasia. Common cavity inner ear deformity.

A case is reported in whom there was a unilateral complete arrest of differentiation of the otocyst associated with an ipsilateral mild hemifacial hypoplasia and auricular abnormalities. The patient's tympanic membrane and VII nerve function were normal and a normal ossicular mass was identified on CT Scan. This case illustrates that development of the middle ear cavity (exclusive of structures on the medial wall), external ear canal and VII nerve can be independent of development of the inner ear and that a unilateral absence of otic capsule differentiation can take place without severe associated abnormalities.

Child, Preschool↗
PubMed1989

Comparison of the identifiability of the low intensity ABR and MLR in the mentally handicapped patient.

The auditory brain stem response and the middle latency response were recorded from low intensity click stimuli in 48 patients with mental handicaps. In the 23 patients (45 ears) with normal hearing thresholds, the ABR was found to have a lower test-retest variability than the MLR. This lower variability will correspond to higher identifiability at threshold. In the 25 patients with a hearing loss, four had MLRs recorded in ears with absent ABRs. In five of these ears no auditory response would have been detected if ABRs alone were recorded. Based on the above findings, the following recommendations can be made. Recording the ABR with open filters is the desired method for threshold detection in most subjects. If no response is obtained it is desirable to record a MLR. The recording of a MLR is probably more important in laboratories recording responses with steep filter slopes, since a greater portion of the slow wave activity, P phi (V) complex, will be phase shifted into the later portion of the time base.

Adolescent↗
PubMed1989

Comparison of the mastoid to vertex and mastoid to high forehead electrode arrays in recording auditory evoked potentials.

The ipsilateral mastoid to vertex and ipsilateral mastoid to high forehead electrode arrays were found to have equal efficacy in recording the auditory brain stem and middle latency responses in both open and closed filtered conditions. It is concluded that the ipsilateral mastoid to high forehead electrode array is a valid clinic alternative for use in evoked response testing.

Audiometry, Evoked Response↗
PubMed1989

Analog and digital filtering of the brain stem auditory evoked response.

This study compared the filtering effects on the auditory evoked potential of zero and standard phase shift digital filters (the former was a mathematical approximation of a standard Butterworth filter). Conventional filters were found to decrease the height of the evoked response in the majority of waveforms compared to zero phase shift filters. A 36-dB/octave zero phase shift high pass filter with a cutoff frequency of 100 Hz produced a 16% reduction in wave amplitude compared to the unfiltered control. A 36-dB/octave, 100-Hz standard phase shift high pass filter produced a 41% reduction, and a 12-dB/octave, 150-Hz standard phase shift high pass filter produced a 38% reduction in wave amplitude compared to the unfiltered control. A decrease in the mean along with an increase in the variability of wave IV/V latency was also noted with conventional compared to zero phase shift filters. The increase in the variability of the latency measurement was due to the difficulty in waveform identification caused by the phase shift distortion of the conventional filter along with the variable decrease in wave latency caused by phase shifting responses with different spectral content. Our results indicated that a zero phase shift high pass filter of 100 Hz was the most desirable filter studied for the mitigation of spontaneous brain activity and random muscle artifact.

Brain Stem↗