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Biomedical subjects

H K Koh

Publications and source records attributed to H K Koh.

At least 19 recordsLinked to original sources
PubMed1999

Genetically engineered transgenic plants with the domain 1 sequence of tobacco mosaic virus 126 kDa protein gene are completely resistant to viral infection.

In many plant RNA viruses, Domains 1, 2 and 3 are conserved in replicase proteins. In order to examine the interference of viral replication by the Domain 1 sequence, we generated transgenic plants transformed with DNA corresponding to the Domain 1 sequence of the TMV 126 kDa protein. This DNA sequence includes the TMV RNA from nucleotides 1 to 2,149, which comprises both the 5'-untranslated and methyl transferase region. The transgenic plants obtained showed complete resistance to TMV infection. The presence of the Domain 1 sequence in the plants completely prevented local necrosis in Nicotiana tabacum cv. Xanthi nc, and any systemic development of symptoms in Nicotiana tabacum Xanthi upon TMV inoculation. Most transgenic plants sustained the conferred resistance even under TMV inoculum concentrations up to as high as 1,000 microg/ml. To detect any accumulation of TMV coat protein or viral RNA in infected transgenic plants, immunochemical tests and Northern blot analyses were carried out. Neither viral RNA or coat protein was detectable in the systemic leaves of the completely resistant transgenic plants, whereas they were accumulated in large quantities in all of the control plants. Because of the conservation of Domain 1 in many plant RNA viruses, the acquisition of resistance to virus infection using the Domain 1 sequence appears to be a very effective strategy for breeding of viral resistant plants.

Genes, Viral↗
PubMed1999

Chemotherapy with etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone in patients with refractory cutaneous T-cell lymphoma.

BACKGROUND: This Phase II study was undertaken to assess the efficacy and toxicity of chemotherapy with etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone (EPOCH regimen) in patients with advanced, refractory cutaneous T-cell lymphoma (CTCL). METHODS: Fifteen patients were treated with a 96-hour continuous infusion of etoposide, vincristine, doxorubicin, bolus cyclophosphamide, and oral prednisone, followed by granulocyte-colony stimulating factor support and trimethoprim/sulfamethoxazole prophylaxis. The median age of the patients was 53 years (range, 17-82 years). Six patients had Sézary syndrome (SS), four patients had visceral involvement, and four patients had anaplastic large cell morphology, three with Ki-1 (CD30) positivity. All patients had disease that was refractory to prior chemotherapy or electron beam irradiation and eight of these patients had received cyclophosphamide, doxorubicin, vincristine, and prednisone. Seven patients had received prior interferon therapy and nine patients had received fludarabine and/or 2-CDA. RESULTS: After a median of 5 cycles (range, 1-9 cycles), 4 patients achieved a complete response (27%) and 8 patients achieved a partial response (53%) for an overall response rate of 80% (95% confidence interval, 52-96%). Three patients with visceral involvement, two of three patients with anaplastic large cell morphology, and one patient with human T-cell lymphoma virus leukemia/lymphoma did not respond. All 12 responders had improvement in skin disease; 2 of 6 patients with SS had complete disappearance of circulating Sézary cells. The median progression free survival was 8.0 months (range, 3-22 months). After a median follow-up of 11.4 months (range, 2-56+ months), the median patient survival was 13.5 months. Grade 3 or 4 hematologic toxicity occurred in 8 patients (61%); 5 of these 8 patients had febrile neutropenia. Six patients developed staphylococcal bacteremia, two patients had disseminated herpes infection, and one patient had Pneumocystis carinii pneumonia. Grade 3 neurotoxicity occurred in one patient. Two patients had a significant decrease in left ventricular ejection fraction and one patient had supraventricular tachycardia. CONCLUSIONS: EPOCH chemotherapy has a high response rate with acceptable toxicity in patients with advanced and refractory CTCL.

Administration, Oral↗
PubMed1999

Screening for malignant melanoma: A cost-effectiveness analysis.

BACKGROUND: Skin cancer is the most common cancer in the United States. Increasing evidence suggests that screening for malignant melanoma is effective, but its cost-effectiveness has not been determined. OBJECTIVE: We attempted to determine the effectiveness and costs of a visual screen to diagnose malignant melanoma in high-risk persons. METHODS: We developed a decision analysis comparing no skin cancer screen with a single screen by a dermatologist. Clinical outcomes included malignant melanoma, nonmelanoma skin cancer, or no skin cancer. Life expectancy and costs of care were projected on the basis of clinical findings. RESULTS: Skin cancer screening increased average discounted life expectancy from 15.0963 years to 15.0975 years. Based on the prevalence of malignant melanoma, however, this translates into an increased discounted life expectancy of 0.9231 years for each person with diagnosed melanoma. Using a cost of $30 per screen, total skin cancer-related costs for a cohort of 1 million people increased from $826 million with no screen to $861 million with screening, with an increase of 1200 years of life. This results in an incremental cost-effectiveness ratio of $29,170 per year of life saved (YLS) with screening. Sensitivity analysis showed that the cost-effectiveness ratio for screening remained below $50,000/YLS if the prevalence of melanoma in the screened population was at least 0. 0009, the probability that a melanoma detected in screening was localized was at least 94.8%, or the cost of each screen was below $57. CONCLUSION: Skin cancer screening in high-risk patients is likely to be associated with a small increase in discounted life expectancy and is reasonably cost-effective compared with other cancer screening strategies.

Cost-Benefit Analysis↗
PubMed1999

Public knowledge, awareness, and perceptions of the association between skin aging and smoking.

BACKGROUND: Although the tobacco industry promotes images of glamour, 2 decades of epidemiologic research have concluded the opposite: smokers have enhanced facial aging and skin wrinkling compared with nonsmokers. OBJECTIVE: The purpose of this study was to obtain information on the public's awareness of the association between cigarette smoking and skin aging. METHODS: In the spring of 1994, the Maine-wide Cooperative Telephone Survey conducted telephone interviews in 678 randomly selected, nonseasonal dwelling units in Maine. From each dwelling unit, one randomly selected adult resident was interviewed to assess awareness of the association of skin aging with smoking. RESULTS: Fifty-eight percent of those persons interviewed had smoked at least 100 cigarettes, and among them, 24% were current smokers (28% men, 21% women). After adjusting for sex, age, and education, current smokers remained less likely to be aware of this association compared with former (prevalence ratio, 0.78; 95% confidence interval, 0.64-0.95) and never smokers (prevalence ratio, 0.87; 95% confidence interval, 0.70-1.07). However, nearly one fourth of smokers in this study believed that most or some smokers would consider this information in their decision to quit, with slightly higher findings in young smokers. CONCLUSION: These findings are of public health importance. While strategies for framing messages about the association between smoking and facial aging await further study, this association deserves to be considered in all tobacco control and counter-advertising campaigns.

Adolescent↗
PubMed1999

Participant satisfaction and value in American Academy of Dermatology and American Cancer Society skin cancer screening programs in Massachusetts.

BACKGROUND: More than 1 million Americans have attended the American Academy of Dermatology's Melanoma/Skin Cancer Screening Programs since 1985. However, there have been no reports of the participants' perceived value, satisfaction, and benefits of skin cancer screening. OBJECTIVE: We attempted to measure the benefits and subsequent screening practices of persons with presumptive positive screening diagnoses. METHODS: A self-administered questionnaire was sent to participants with positive screening diagnoses in Massachusetts. RESULTS: Of the 643 respondents, 81% rated their satisfaction as high and 84% had similar ratings for the value of the screening. Screenings apparently led to an increase in self-screening (60% before screening compared with 84% after screening). CONCLUSION: Although screening appears to have relatively strong benefits, further studies should be conducted nationally.

Adult↗
PubMed1999

Medical students' knowledge, attitudes, skills, and practices of cancer prevention and detection.

BACKGROUND: Surveys of U.S. physicians show deficiencies in cancer detection and counseling skills. Thus, there is a compelling need to provide skills teaching during medical school for cancers with preventable mortality and for counseling techniques for smoking prevention and cessation. METHODS: In advance of the integration of initiatives for cancer education into the medical school curriculum, the authors conducted a baseline survey of students' knowledge, attitudes, skills, practices, observation, and training (KASPOT) related to cancer education. Eighty-one percent of Boston University School of Medicine students (n = 499) completed surveys. RESULTS: The students reported higher levels of KASPOT for breast and cervical cancers, compared with skin cancer examination or tobacco use cessation or prevention counseling. More than half of third- and fourth-year students reported that too little emphasis was given to cancer control education. CONCLUSIONS: It appears that students' practice and skills for detection of the most common cancer (skin cancer), and for cancers with the greatest mortality (tobacco-related cancers) are deficient. Revisions in medical students' curricula should seek to address these shortcomings.

Clinical Competence↗
PubMed1999

The Falmouth Safe Skin Project: evaluation of a community program to promote sun protection in youth.

A multidimensional community-based skin cancer prevention program was conducted in Falmouth, Massachusetts, combining community activism with publicity campaigns and behavioral interventions to improve sun protection knowledge; attitudes; and practices in parents, caregivers, and children. The program was associated with improvements in target outcomes, based on two telephone surveys of random samples of parents (n = 401, 404). After program implementation, fewer parents reported sunburning of their children, particularly among children 6 years old or younger (18.6% in 1994 vs. 3.2% in 1997), and more parents reported children using sunscreen, particularly continuous use at the beach (from 47.4% to 69.9% in younger children). Hat and shirt use did not increase. Improvements also were seen in parent role modeling of sun protection practices, parents' self-efficacy in protecting children from the sun, and sun protection knowledge. While these findings must be interpreted cautiously, they do suggest that this project was effective in promoting sun protection.

Adolescent↗
PubMed1998

Evaluation: methods and strategy for evaluation--Massachusetts.

Various challenges exist when evaluating statewide, community-based public health initiatives and these need to be addressed by tobacco control programs. There are factors inherent in public health initiatives that can make it difficult to assess causality and effectiveness. These include initial design elements, funding mandates, duration of program and resources allocated for evaluation. In addition, outside efforts to undermine the initiative also must be taken into consideration, when evaluating effectiveness. This article focuses on these and other challenges encountered by the Massachusetts Tobacco Control Program and presents information on the state specific tobacco surveys conducted for the Program.

Data Collection↗
PubMed1998

Do pediatricians counsel families about sun protection?: a Massachusetts survey.

BACKGROUND: Pediatric visits during summer months may be especially opportune times for sun protection counseling for children and their parents. Few data exist on the extent of such counseling. OBJECTIVE: To begin to assess this, we surveyed practicing Massachusetts pediatricians to examine current attitudes and practices of sun protection counseling. DESIGN AND SETTING: Surveys mailed to Massachusetts pediatricians. RESULTS: We received surveys from 756 (60%) of 1263 eligible Massachusetts pediatricians. Almost 70% indicated that they recommended safe sun practices to more than 50% of their patients and their parents during the summer months. Counseling regarding seat belt use, bicycle helmet use, and smoking prevention were ranked higher in priority than sun protection counseling by pediatricians; nutritional guidelines were noted by pediatricians to be a parent's most frequent concern. Four variables were independently associated with a practitioner's providing safe sun recommendations to more than 50% of parents and children: (1) private setting and health maintenance organization practitioners as opposed to academic physicians, (2) high ranking of patients' safe sun knowledge, (3) high priorities of both parents and physicians for sun protection counseling and parental knowledge of safe sun practices relative to other recommendations, and (4) pediatrician interest in receiving instructional materials. CONCLUSIONS: For the most part, summer sun protection counseling among Massachusetts pediatricians seems well integrated into standard practice. Most pediatricians rated their confidence level as high for discussing sun protection and only a few cited inadequate training or poor reimbursement as barriers toward improved counseling. Small steps, such as providing more instructional materials to patients and using office-based reminder systems, may improve the quality of sun protection counseling practices. Incorporating sunburn prevention into the list of routinely recommended injury prevention guidelines for pediatricians should be considered.

Adolescent↗
PubMed1998

Factors associated with smoking among children and adolescents in Connecticut.

INTRODUCTION: The age of smoking initiation has dropped over the past four decades. Since behaviors and attitudes adopted in late childhood or early adolescence predict future smoking, it is important to understand the smoking and other risk-taking behaviors and attitudes of children aged 12 and younger. The goal of the analyses presented here was to describe behavioral and attitudinal factors associated with smoking among elementary school (grades 4-6), middle school (grade 7-8), and high school (grades 9-12) students in Connecticut. METHODS: We have used data from 8 years (1988-1996) of an anonymous, self-administered health risk appraisal survey given to children and adolescents in self-selected public and private schools. We compared the proportion of smokers and nonsmokers who reported various behaviors and attitudes and compared them with the chi-square test. RESULTS: Fifteen percent (n = 4,884) of the total population (n = 31, 861) were current smokers. At all grade levels, current smokers were more likely than nonsmokers to engage in risk-taking behaviors, and to report more stress and depression. Indicators of risk-taking and stress were also associated with the intent to smoke among children in grades 4-6. CONCLUSIONS: Smoking occurs within the context of other risk-taking behavior and psychological distress, among both children and older adolescents. Our data provide support for the idea of early identification and targeting of children at high risk of smoking in elementary school, possibly as early as grade four.

Adolescent↗
PubMed1998

Public health interventions for melanoma. Prevention, early detection, and education.

Worldwide melanoma control programs that include some combination of primary prevention, education, and screening activities have only recently begun to undergo an evaluation process. More studies with rigorous design and evaluation are needed. Until then, the proper public health policy guidelines for melanoma control, especially screening, are open to debate. Future studies must determine how screening, early detection, case finding, and education can best be used to reduce mortality and achieve optimal melanoma control.

Humans↗
PubMed1998

Early detection of cutaneous lymphoma.

Cutaneous lymphomas comprise a spectrum of diseases characterized by infiltration of the skin by malignant lymphocytes. The clinical manifestations of cutaneous lymphomas vary, and they can mimic benign dermatoses, as well as nodal or visceral malignancies with cutaneous spread. Cutaneous lymphomas are divided into T-cell lymphomas and B-cell lymphomas. Cutaneous T-cell lymphomas include mycosis fungoides, Sézary syndrome, lymphomatoid papulosis, CD30+ large cell lymphoma, and adult T-cell leukemia/lymphoma. The extent and severity of skin manifestations in cutaneous T-cell lymphomas are prognostic indicators of extracutaneous involvement. Primary cutaneous B-cell lymphomas comprise 10% to 25% of all primary cutaneous non-Hodgkin's lymphomas and are classified according to their cell of origin. Most cutaneous B-cell lymphomas have an indolent course and excellent prognosis when compared to their nodal counterparts. Many factors have been implicated in the etiology of cutaneous lymphomas, including chemical and drug exposures, as well as microbial agents, such as the Epstein-Barr virus (EBV), human T-lymphocyte virus-1 (HTLV-1), and Borrelia burgdorferi. Immunohistochemistry and lymphocyte-receptor gene rearrangement studies are useful in distinguishing malignant from benign conditions.

Diagnosis, Differential↗
PubMed1998

Multiple cerebellar infarction due to vertebral artery obstruction and bulbar symptoms associated with vertical subluxation and atlanto-occipital subluxation in ankylosing spondylitis.

Ankylosing spondylitis (AS) results in disease-specific inflammation at the site of ligamentous insertion into the bone. Atlantoaxial joint subluxation and vertical subluxation of the axis may occur as a consequence of instability resulting from the inflammatory process. Spontaneous anterior atlantoaxial subluxation is a well recognized complication in about 2% of patients with AS, and presents with or without signs of spinal cord compression. Vertical subluxation may follow anterior or posterior subluxation. It was noted in 3-8% of patients with rheumatoid arthritis, but is an exceedingly rare complication of AS. Moreover, it has never been reported that multiple cerebellar infarction and bulbar symptoms developed spontaneously due to atlanto-occipital subluxation and vertical subluxation in a patient with a long [corrected] history of AS. We describe a man with AS who developed multiple cerebellar infarction due to vertebral artery obstruction and bulbar symptoms associated with atlanto-occipital subluxation and vertical subluxation.

Arterial Occlusive Diseases↗
PubMed1997

Evaluation of the Ultraviolet Index: media reactions and public response.

BACKGROUND: In response to the increasing rate of skin cancer, particularly melanoma in the United States, the Environmental Protection Agency, the National Weather Service, the Centers for Disease Control and Prevention, National Association of Physicians for the Environment, and the American Academy of Dermatology, developed the Ultraviolet Index (UVI) to inform the public of the strength of the sun's rays and advise on methods for sun protection. OBJECTIVE: Our purpose was to evaluate the extent to which television stations and newspapers reported the UVI and assess the public's response to it. METHODS: To evaluate the effect of this effort, we surveyed television weather forecasters at 185 stations and examined weather pages in 54 newspapers in 58 cities that received the UVI reports. We also conducted a population probability telephone survey of 700 white adults (18 years of age and older) in these 58 cities. RESULTS: Seventy-one percent of the 169 stations that provided survey data for both 1994 and 1995 broadcast the UVI; 61% of newspapers reported the UVI. Nearly 64% of the 700 respondents (n = 445) had heard of the UVI. Of these respondents, 38% (n = 170) stated that they or their family changed their sun protection practices as a result of the UVI. CONCLUSION: The majority of television weather forecasters and newspapers reported the UVI. Most of the public was aware of the UVI, causing some to change sun protection practices. Further evaluation is required to maximize the effect of the UVI on sun protection practices.

Adult↗
PubMed1997

Proceedings of the International Consensus Conference on Cutaneous T-cell Lymphoma (CTCL) Treatment Recommendations. Boston, Massachusetts, Oct. 1 and 2, 1994.

At the International Consensus Conference for Cutaneous T-Cell Lymphoma (CTCL) Treatment Recommendations (held in Boston, Massachusetts, Oct. 1 and 2, 1994), international experts were asked to assess where consensus existed and to identify areas that required clinical research. We review the epidemiology, pathology, and immunology of CTCL, summarize the important areas in which consensus exists, and discuss newer targeted therapies.

Humans↗
PubMed1997

Adjuvant therapy for cutaneous malignant melanoma.

We discuss the current status of adjuvant therapy for melanoma by first reviewing the rationale and goals of adjuvant therapy and then analyzing the results of published randomized trials. We pay particular attention to adjuvant interferon trials that raise many challenging issues in the management of patients with melanoma at high risk of recurrence. Past adjuvant trials have used immunotherapeutic approaches, chemotherapy, radiation therapy, as well as hormonal and retinoid therapy. We also summarize ongoing adjuvant trials.

Chemotherapy, Adjuvant↗
PubMed1997

Is it lymphoma or lymphomatoid papulosis?

Distinguishing malignancy from premalignant conditions can be difficult. Controversy surrounds both the clinical and histologic criteria used to distinguish lymphomatoid papulosis, a benign disorder, from CD30+ anaplastic large-cell lymphoma. Three case histories illustrate important points in categorizing different lymphoproliferative disorders as benign or malignant. We emphasize a multidisciplinary approach to improve diagnosis and patient management.

Aged↗