Dental procedures among children age birth to 20, United States, 1999 and 2009

OBJECTIVE

To describe dental procedures received by US children and adolescents by poverty status and dental insurance coverage.

METHODS

Data for this analysis came from the 1999 and 2009 Medical Expenditure Panel Surveys. The primary outcome variable represented the types of dental procedures that were received during dental visits in the preceding year. Descriptive variables included dental insurance and poverty status. Analysis was restricted to children from birth to 20 years.

RESULTS

Overall, diagnostic (41.2 percent) and preventive (35.8 percent) procedures accounted for most of the procedures received by children from birth to 20 years of age, while restorative procedures accounted for just 5 percent. Children from low-income families received a higher proportion of restorative procedures than children in higher-income families. The proportion of diagnostic and preventive services was lower among uninsured children than among publicly insured children. Orthodontic services, on the other hand, represented a greater percentage of these procedures among uninsured children than among publicly insured children.

DISCUSSION

The vast majority of procedures received by children from birth to 20 years were diagnostic and preventive. Most children with at least one dental visit received a diagnostic or preventive service. Between 1999 and 2009, the proportion of all services received accounted for by diagnostic or preventive services increased. However, the proportion in which each type of procedure was received by children who made at least one visit who received did not change.

Expanding the physician's role in addressing the oral health of adults

Many disadvantaged adults visit physicians or hospital emergency departments to receive relief from dental pain. Physicians also see patients with general questions or concerns about their oral health. Unfortunately, because physicians generally have received little oral health training, patients often do not receive comprehensive emergency services or appropriate counseling. This situation has begun to change, as there has been a growing sentiment among the dental and medical communities that better integration and coordination between medicine and dentistry would be beneficial. Reports from the Institute of Medicine and professional associations and foundations reflect the need for better integration. I have outlined the rationale for and progress toward expanding the physician's role in addressing the oral health of adults.

Health literacy impact on patient-provider interactions involving the treatment of dental problems

Health literacy-related problems can interfere with effective doctor-patient communication and effective patient care. This study examined several health literacy-related markers for patients seeking treatment in hospital emergency departments and physician and dentist offices for dental problems and injuries. Participants consisted of low-income white, black, and Hispanic adults who had experienced a dental problem or injury during the previous twelve months and who visited a hospital emergency department, physician, or dentist for treatment. A stratified random sample of Maryland households participated in a cross- sectional telephone survey. Interviews were completed with 94.8 percent of 423 eligible individuals. Multivariable logistic regression analyses were performed. Only 10.0 percent of the respondents expressed a difficulty understanding what they were told by the health provider, while 4.9 percent expressed a difficulty understanding the dental or medical forms they were asked to complete and 6.9 percent reported that they had difficulty getting the health provider to understand their dental problem or injury. Logistic regression analysis found that males and Hispanics were significantly (p<0.05) more likely to experience health literacy-related problems. In general, respondents did not express health literacy-related problems. Additional research is needed to identify health literacy-related barriers to effective patient-provider communication.

Comparison of patient centeredness of visits to emergency departments, physicians, and dentists for dental problems and injuries

BACKGROUND

Patient-centered care has a positive impact on patient health status. This report compares patient assessments of patient centeredness during treatment in hospital emergency departments (EDs) and physician and dentist offices for dental problems and injuries.

RESEARCH DESIGN

Participants included low-income White, Black, and Hispanic adults who had experienced a dental problem or injury during the previous 12 months and who visited an emergency department, physician, or dentist for treatment. A stratified random sample of Maryland households participated in a cross-sectional telephone survey. Interviews were completed with 94.8% (401/423) of eligible individuals. Multivariable logistic regression analyses were performed.

RESULTS

The measure of predictive power, the pseudo-R2s, calculated for the logistic regression models ranged from 12% to 18% for the analyses of responses to the measures of patient centeredness (satisfaction with treatment, careful listening, thorough explaining, spending enough time, and treated with courtesy and respect). EDs were less likely than dentists to treat patients with great courtesy and respect.

CONCLUSIONS

Further research is needed to identify factors that support patient-centered care.

Treatment of canine haemangiosarcoma with suberoylanilide hydroxamic acid, a histone deacetylase inhibitor

A case report is presented by describing the treatment of a 12-year-old dog - diagnosed with haemangiosarcoma (HSA) - with suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor. The drug was administered orally, on a daily basis, approximately 2 weeks post-splenectomy at a dose of 3 mg kg(-1). HSA is a lethal malignancy of the endothelium, which is usually disseminated by the time it is diagnosed. Median survival time, usually, is no longer than 80 days. Following treatment with SAHA, no sign of malignant growth could be discerned by means of diagnostic abdominal ultrasound, chest X-ray or with the help of clinical symptoms, over a period of >1000 days. The precise mechanism by which HDAC inhibitors exert their anti-cancer effects is uncertain, but evidence suggests that exposure to SAHA generates hyperacetylated chromosomal histones, which, in turn, facilitates the expression of tumour suppressor genes turned off by epigenetic mechanisms during neoplastic transformation of the endothelium.

Toothache pain: behavioral impact and self-care strategies

A computer-assisted telephone interview in Maryland of adults who had low income and were Hispanic, Black, and White and who had experienced a toothache during the previous 12 months was conducted. Respondents reported a high prevalence of toothaches, with 44.3% having experienced more than five toothaches during the preceding 10 years. Pain intensity associated with the most recent toothache was high with 45.1% of the respondents reporting the highest pain possible. Pain interfered with many aspects of normal functioning. Self-care strategies generally took precedence over professional health services. Pain sufferers used a combination of self-care and formal care strategies. Initial strategies most often focused on nonprescription medicines(home remedies and prayer. The majority of respondents ultimately sought pain relief from a dentist. We identified a number of significant differences in the strategies used across racial/ethnic groups.

The role of non-dental health professionals in providing access to dental care for low-income and minority patients

The disadvantaged suffer disproportionately from dental problems. These persons are more likely to have untreated oral health problems and associated pain, and also are more likely to forego dental treatment even when in pain. There has been increased emphasis on the potential role of physicians in alleviating oral health disparities, especially among children. In addition, many adults lacking access to traditional dental services seek care and consultation from hospital emergency departments, physicians, and pharmacists. The delivery of oral health care services by non-dental health professionals may assume increasing importance as the population continues to age and becomes more diverse. This is because, in general, the elderly and ethnic and racial minorities face significant economic barriers to accessing private dental services.

Low-income and minority patient satisfaction with visits to emergency departments and physician offices for dental problems

OBJECTIVES

Individuals lacking access to dentists may use hospital emergency departments (EDs) or physicians (MDs) for the management of their dental problems. This study examined visits by minority and low-income individuals to physicians and hospital emergency departments for the treatment of dental problems with the goal of exploring the nature of treatment provided and patient satisfaction with the care received.

METHODS

Eight focus group sessions were conducted with 53 participants drawn from low-income White, Black, and Hispanic adults who had experienced a dental problem and who had sought MD/ED care at least once during the previous 12 months.

RESULTS

Toothache pain or more generalized jaw/face pain was the most frequent oral problem resulting in MD/ED visits. Pain severity was the principle reason for seeking care from MDs/EDs, with financial barriers most often mentioned as the reason for not seeking care from dentists. Expectations of MD/ED visits were generally consistent with care received; most participants limited their expectations to the provision of antibiotics or pain medication. Nearly all of the participants thought they would eventually need to see a dentist for resolution of their dental problem.

CONCLUSIONS

Poor/minority individuals seek relief from oral pain through MDs/ EDs while recognizing that such care is not definitive.

Coping with toothache pain: a qualitative study of low-income persons and minorities

OBJECTIVES

This study examined the behavioral impact of toothache pain as well as self-care strategies for pain relief among minority and low-income individuals.

METHODS

Eight focus group sessions were conducted with 66 participants drawn from low-income non-Hispanic White, non-Hispanic Black, and Hispanic adults over the age of 20 who had experienced a toothache during the previous 12-month period and who had utilized self-care or care from a nondentist.

RESULTS

Toothache pain was described as intense, throbbing, miserable, or unbearable. Focus group participants indicated that toothache pain affected their ability to perform normal activities, such as their job, housework, social activities, sleeping, talking, and eating, as well as making them depressed and affecting their social interactions. Numerous prescription and nonprescription medications as well as home remedies and self-care strategies were used for pain relief, although these were generally of limited and uncertain benefit. While receiving care at a dental office was the most preferable option for care, most participants reported multiple barriers, including the cost of dental care that resulted in long delays in seeking dental care. The main reason for eventually seeking dental care was the severity of the pain.

CONCLUSIONS

Although removing financial barriers alone may not lead to preventive dental visits, it would facilitate more timely visits to dentists to treat toothache pain.

Soy isoflavone intake and estrogen excretion patterns in young women: effect of probiotic administration

BACKGROUND

Soy isoflavones may lower breast cancer risk through altered hepatic estrogen metabolism, leading to increased urinary excretion ratios of 2-hydroxyestrone (20HE1) to 16a-hydroxyestrone (16alphaOHE1).

MATERIALS AND METHODS

Urinary excretion of 20HE1/16alphaOHE1 was measured in 36 healthy, pre-menstrual women before and after ingestion of a soy-protein formula containing 120 mg of isoflavone daily for one month. Since isoflavone absorption and metabolism depends on intestinal bacteria, effects of co-administration of Lactobacillus GG (2 x 10(12)) on estrogen ratios and isoflavone excretion were studied. Urinary isoflavone excretion measurements assessed compliance.

RESULTS

Soy isoflavone ingestion induced quantitative differences in urinary excretion of estrogen metabolites and isoflavones but failed to alter 20HE1/16alphaOHE1 ratios. Co-administration of Lactobacillus GG with soy reduced excretion of total and individual isoflavones by 40% (p=0.08), without altering 2OHE1/16alphaOHE1 ratios.

CONCLUSION

Isoflavone-rich soy protein administration alone, or with probiotic supplement, did not alter urinary excretion of estrogen metabolites in premenopausal women. However, adding concentrated probiotics may alter isoflavone bioavailability.

Visits to non-dentist health care providers for dental problems

BACKGROUND AND OBJECTIVES

Although poor and minority adults experience greater levels of dental disease, they frequently face cost and other system-level barriers to obtaining dental care. These individuals may be forced to use physicians or hospital emergency rooms for the treatment of dental problems. This study was conducted to gain a better understanding of the role that non-dentist health care providers play in providing access to oral health care services.

METHODS

Dental conditions and dental condition-related visits to non-dentist health care providers during 2001 for the US civilian noninstitutionalized population were analyzed using data from the Household Component of the Medical Expenditure Panel Survey.

RESULTS

During 2001, approximately 3.1% of the US population experienced at least one dental problem reported outside of the traditional office-based dental delivery system. Of these, approximately 2.7% received care in a hospital emergency room setting while 7.0% received care in other medical settings. A majority (68.1%) had contact with the formal health care system via a prescription associated with their identified dental problem. Approximately 22.5% did not seek any formal treatment for their problem. Overall, low-income individuals were more likely not to seek formal care than were middle/high-income individuals (32.5% versus 19.7%).

CONCLUSIONS

Individuals not using traditional sources of dental care appear to have greater access to physician offices and other medical settings than to hospital emergency rooms for the treatment of dental problems.

Adult patient visits to physicians for dental problems

BACKGROUND AND OBJECTIVES

Most physicians lack substantive training in dentistry and are usually not capable of providing definitive dental care. Therefore, physician offices are generally not the most appropriate site for the management of most dental problems. This study was conducted to examine the rate with which patients visit physician offices for the treatment of dental problems and their satisfaction with the treatment received.

METHODS

Data on dental related problems were collected through a random telephone survey of English-speaking Maryland residents over the age of 20. A random digit dial methodology was used to generate the sampling frame. A total of 811 interviews were conducted. The overall survey has a margin of error of +/- 3.44% at the 95% confidence level.

RESULTS

5.6% of respondents reported seeing a physician for a dental problem during the prior year. Almost 80% reported being satisfied with the treatment received, while 36.4% reported needing follow-up care with a dentist for treatment of the same problem. Respondents expressing greater satisfaction with their visit to the physician were less likely to report needing to see a dentist for follow-up care (p < .05).

CONCLUSIONS

Additional studies are needed to assess the quality and appropriateness of physician management of dental problems.

Attitudes of advanced dental education students toward individuals with AIDS

The number of patients with HIV/AIDS who receive dental care is increasing. This study was undertaken to gain a better understanding of the attitudes of dentists enrolled in postgraduate training toward AIDS and homosexuals. Each respondent received a 500-word patient case vignette and two scales for recording impressions of the person described in the vignette. There were four vignettes, identical except that the portrayed individual's illness was identified as either AIDS or leukemia and sexual preference as either homosexual or heterosexual. Two-way analyses of variance and t tests (p<.05) revealed a bias toward individuals with AIDS and toward homosexuals. Respondents reacted more negatively to both groups on the Social Interaction Scale as seen in total scale scores as well as to individual scale items. In addition, although overall Prejudicial Evaluation Scale scores displayed no evidence of bias, several individual scale items did. It is important to ensure that dentists' attitudes toward patients with AIDS and homosexuals are not a barrier to these patients receiving the best possible care. Therefore, dental education programs at all levels should give consideration to interventions to address provider attitudes and potential biases.

Attitudes of dental hygiene students toward individuals with AIDS

This study was undertaken to gain a better understanding of dental hygiene students' attitudes toward AIDS and homosexuals. Each respondent received a 500-word patient case vignette and two scales for recording impressions of the person described in the vignette. There were four vignettes, identical except that the portrayed individual's illness was identified as either AIDS or leukemia, and sexual preference as either homosexual or heterosexual. No differences in overall ratings on either scale were noted based on the patient's disease status or sexual preference or the interaction between sexual preferences with disease type. Similarly, neither scale displayed significant differences on any of the individual items based on the patient's sexual preference. There were, however, significant differences for several individual items on both scales based on the patient's disease type; students responded more negatively to individuals with AIDS. It appears, therefore, that the hygiene students displayed no bias toward homosexuals and only very minimal bias toward individuals with AIDS.

Medicaid coverage and utilization of adult dental services

This study evaluated the economic impact of a policy change in adult Maryland Medicaid dental benefits that eliminated reimbursements to dentists. We examined all claims for 2 years before and after the change. Reimbursements to dentists fell to zero from their preenactment period annual rate of US 7.6 million dollars; other care settings simultaneously generated an additional US 232,470 dollars savings during the postenactment period. Medicaid's goal to reduce costs was achieved; however, disadvantaged patients may have been confused by the policy change and likely suffered poorer health outcomes and paid for treatment out of pocket, found free clinics, or received free care from generous dentists.

Dental visits among older U.S. adults, 1999

BACKGROUND

The proportion of older adults in the United States will continue to grow during the next few decades. Aging populations will bring unique challenges to dentistry. Understanding dental visit patterns will help the profession become prepared.

METHODS

The authors used data from the 1999 National Health Interview Survey to describe dental visit patterns among adults aged 55 years or older. Outcome variables included presence of a dental visit in the previous year, reasons for the last dental visit and reasons for not having had a dental visit. Descriptor variables included age, sex, race/ethnicity, poverty status, region, private dental insurance status and dentition status.

RESULTS

Approximately 71 percent of dentate and 20 percent of edentulous adults had had a dental visit in the previous year. Among dentate adults, age, sex, race/ ethnicity, poverty status, region and dental insurance were associated with visits. Among edentulous adults, age, poverty status and dental insurance were associated with visits. Among all older adults, the main reason for a visit was preventive/ diagnostic. Edentulous adults also were likely to visit for problems. The majority of adults who had not had a dental visit did not recognize a need for one; however, dentate adults were more likely to recognize a need than were edentulous adults. For those who recognized a need but did not visit a dentist, cost was a prevalent barrier.

CONCLUSIONS

Among those who visited a dentist, most went for a diagnostic/preventive procedure. Among those who did not visit a dentist, most did not recognize a need to do so. Cost remains a serious barrier.

CLINICAL IMPLICATIONS

Some older adults recognize a need to visit a dentist, whereas others (particularly the edentulous) do not. As more adults recognize their oral health care needs, cost may prevent some from seeking care.

Hospital admissions associated with nontraumatic dental emergencies in a Medicaid population

Few studies have examined visits to hospital EDs and subsequent admission for the treatment of nontraumatic dental emergencies. The present study of Medicaid-eligible adults was conducted to gain a better understanding of the magnitude of this problem. Data tapes describing adult Medicaid patients' hospital ED and admission claims were obtained from the Maryland Medicaid Management Information System. The database contained information on all claims made to Maryland Medicaid during the period February 16, 1991, to February 15, 1995. There was a total of 4326 dental-related ED claims, which resulted in 85 hospital admissions. Thus, approximately 2% of dental-related ED visits during the 4-year study period resulted in a hospital admission. The mean total cost for claims associated with hospital admissions was $5793 US dollars, whereas the minimum cost was $949 and the maximum was $43,524 US dollars. Although the frequency of hospital admissions associated with nontraumatic dental emergencies is not great, a hospital admission is among the most extreme consequences of failing to prevent or treat dental problems. Although some hospital admissions related to dental problems could be unavoidable, further studies are needed to better understand mechanisms for reducing the use of EDs for care best provided in community-based dental offices.

A Medicaid population's use of physicians' offices for dental problems

OBJECTIVES

This study evaluated how the elimination of Medicaid reimbursement to dentists for the treatment of adult dental problems affected patients' visits to physicians.

METHODS

Data tapes describing physicians' claims for adult Medicaid patients were obtained from the Maryland Medicaid Management Information System. The database contains information on all claims made to Maryland Medicaid, including date, provider, International Classification of Diseases, Ninth Revision, Clinical Modification Manual code, and payments.

RESULTS

A total of 5334 individuals made physician's office claims related to dental problems sometime during the 4-year study period. The rate of dental-related claims by physicians decreased by 8% after the policy change.

CONCLUSIONS

Visits to physicians' offices decreased even though an increase might have been expected because of the elimination of access to dentists in private practice. Patients might have assumed that if visits to dentists would no longer be paid for, neither would visits to physicians' offices.

Effect of soy protein isolate and conjugated linoleic acid on the growth of Dunning R-3327-AT-1 rat prostate tumors

BACKGROUND

Epidemiologic and animal model studies suggest that consumption of soy isoflavones may be associated with reduced risk of prostate cancer (PC). In addition, animal model studies suggest that conjugated linoleic acid (CLA), a natural positional isomer of linoleic acid, inhibits tumor growth in various models, including models of PC.

METHODS

Based on the above-mentioned data, the objective of the present study was to test the hypothesis that supplementation of the diet with combinations of isoflavone-rich soy protein isolate and CLA would act to inhibit the growth of androgen-independent R-3327-AT-1 rat prostate tumor cells inoculated ectopically into male Copenhagen rats.

RESULTS

The results of this study indicate that neither an isoflavone-rich soy protein isolate (SPI), nor CLA inhibit the in vivo growth and development of prostate tumor cells when administered in the diet either singly or in combination. Moreover, at the highest concentrations SPI and CLA (i.e., 20% SPI, 1% CLA), there was a statistically significant increase in tumors volume over controls. Administration of SPI at 10% in the diet also enhanced tumor growth, whereas at 5%, SPI exerted no measurable effect. CLA administration alone had no observable effects on AT-1 tumor growth.

CONCLUSION

These results, in an established rat model, suggest caution in using isoflavone-rich SPI in human studies involving advanced hormone-refractory prostate cancer until further investigation of these effects are completed.

A review of animal model studies of tomato carotenoids, lycopene, and cancer chemoprevention

There are relatively few reports on the cancer chemopreventive effects of lycopene or tomato carotenoids in animal models. The majority, but not all, of these studies indicate a protective effect. Inhibitory effects were reported in two studies using aberrant crypt foci, an intermediate lesion leading to colon cancer, as an end point and in two mammary tumor studies, one using the dimethylbenz(a)anthracene model, and the other the spontaneous mouse model. Inhibitory effects were also reported in mouse lung and rat hepatocarcinoma and bladder cancer models. However, a report from the author's laboratory found no effect in the N-nitrosomethylurea-induced mammary tumor model when crystalline lycopene or a lycopene-rich tomato carotenoid oleoresin was administered in the diet. Unfortunately, because of differences in routes of administration (gavage, intraperitoneal injection, intra-rectal instillation, drinking water, and diet supplementation), species and strain differences, form of lycopene (pure crystalline, beadlet, mixed carotenoid suspension), varying diets (grain-based, casein based) and dose ranges (0.5-500 ppm), no two studies are comparable. It is clear that the majority of ingested lycopene is excreted in the feces and that 1000-fold more lycopene is absorbed and stored in the liver than accumulates in other target organs. Nonetheless, physiologically significant (nanogram) levels of lycopene are assimilated by key organs such as breast, prostate, lung, and colon, and there is a rough dose-response relationship between lycopene intake and blood levels. Pure lycopene was absorbed less efficiently than the lycopene-rich tomato carotenoid oleoresin and blood levels of lycopene in rats fed a grain-based diet were consistently lower than those in rats fed lycopene in a casein-based diet. The latter suggests that the matrix in which lycopene is incorporated is an important determinant of lycopene uptake. A number of issues remain to be resolved before any definitive conclusions can be drawn concerning the anticancer effects of lycopene. These include the following: the optimal dose and form of lycopene, interactions among lycopene and other carotenoids and fat soluble vitamins such as vitamin E and D, the role of dietary fat in regulating lycopene uptake and disposition, organ and tissue specificity, and the problem of extrapolation from rodent models to human populations.

Nutrition and prostate cancer: a review

Despite intense efforts, little is known about the etiology of prostate cancer, and treatment of advanced forms of the disease has had limited success. Nonetheless, epidemiologic studies combined with animal model and in vitro experiments indicate that natural components of the diet, including n-3 PUFA, the carotenoid lycopene, and the trace element selenium, may serve as chemopreventive agents that suppress the growth and dissemination of neoplastic prostate cells. Until further study, however, soy isoflavones should be viewed with some caution, especially as adjuvant's to chemotherapy, in patients with hormone-refractory prostate cancer. Future studies, using different forms and doses of selenium and tomato carotenoids, may shed new light on the etiology and prevention of prostate cancer.

Dental visits to hospital emergency departments by adults receiving Medicaid: assessing their use

BACKGROUND

Pain from toothaches represents a significant problem. People lacking access to private dental services may use hospital emergency departments, or EDs. In 1993, Maryland eliminated Medicaid reimbursement to dentists for adult emergency services.

METHODS

The authors used the change in Medicaid policy that eliminated dentist reimbursement to establish two study periods. Data tapes describing patients' use of EDs were obtained from the Maryland Medicaid Management Information System. A total of 3,639 people visited EDs for dental problems sometime during the four-year study period.

RESULTS

After controlling for age, race and sex, the authors found that the rate of ED claims was 12 percent higher in the postchange period than in the prechange period. Comparisons between periods show significant rate increases during the postchange period for men, whites, African-Americans and patients aged 21 through 44 years and 45 through 64 years.

CONCLUSIONS

The change in Medicaid policy that eliminated dentist reimbursement and participation in the program appears to have increased the use of EDs for the treatment of dental problems. Practice Implications. Many EDs lack dental services and are not capable of providing definitive treatment. When definitive treatment is not provided, this pattern of care may be repeated if patients are forced to return for treatment.

Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, suppresses the growth of carcinogen-induced mammary tumors

Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, has been shown to inhibit the development of N-methylnitrosourea (NMU)-induced rat mammary tumors when fed in the diet continuously for the duration of the carcinogenic process. The present study was designed to determine whether the inhibitory effects of SAHA occur during the initiation process or at subsequent stages in the carcinogenic process. In addition, animals with established NMU tumors were administered SAHA to determine whether SAHA could inhibit the continued growth of established mammary tumors. It was found that SAHA fed at 900 ppm in the diet inhibited tumor yields when administered from 14 days prior to NMU administration to termination (-14 to +130) and from +14 and +28 days to termination. However, SAHA had no effect on tumor yields when administered from -14 to +14 or from -14 to +50 days and then returned to the control diets for the remainder of the experimental period (130 days). These results indicate that the inhibitory effects of SAHA are not exerted at the initiation phase of NMU-induced mammary tumorigenesis and appear, instead, to inhibit the subsequent stages in tumor development. Of most interest was the ability of SAHA to inhibit the growth of established mammary tumors. Administration of SAHA in the diet at 900 ppm resulted in significant inhibition of established tumor growth. Thirty-two percent of SAHA-treated tumors exhibited partial regression compared to 12% of controls, growth was stabilized in 24% of treated tumors compared to 12% of controls while 11% exhibited complete regression compared to 0% of controls. Collectively, SAHA-treated tumors exhibited a 7-fold reduction in growth compared to untreated tumors over the test period. The results of this animal model study indicate that SAHA, when fed in the diet, serves as both a chemopreventive and chemotherapeutic agent in the absence of any detectable side effects.

LAS, a novel selective estrogen receptor modulator with chemopreventive and therapeutic activity in the N-nitroso-N-methylurea-induced rat mammary tumor model

The N-nitroso-N-methylurea-induced rat mammary tumor model was used to conduct two types of studies: a prevention study designed to test the ability of the novel selective estrogen receptor modulator lasofoxifene (LAS) to inhibit the development of mammary tumors, and a treatment study designed to test the inhibitory effect of LAS on the growth of established tumors. The prevention study indicated that LAS markedly delayed the emergence of N-nitroso-N-methylurea-induced tumors to an extent similar to that obtained by the established antiestrogen tamoxifen (TAM). At the highest dose administered, both TAM and LAS reduced tumor incidence by 75% and total tumor number by 90% relative to the controls. LAS also reduced the multiplicity of tumors, i.e., the mean number of tumors per rat, and resulted in substantially smaller total tumor burden. In the treatment study, LAS significantly inhibited tumor growth compared with the controls. In addition, whereas none of the untreated tumors regressed completely over the experimental period, 40% of LAS-treated tumors regressed by >50% at the highest dose (10 mg/kg daily). The results of this study in a rat mammary tumor model indicate that LAS has both chemopreventive and chemotherapeutic effects quantitatively comparable with those of TAM.

Feeding thiol-containing compounds, derived from vegetables, fails to inhibit N-methylnitrosourea-induced mammary tumorigenesis

Various thiol-containing compounds have been shown to inhibit chemically-induced tumors in animal models. Two thiol-containing compounds derived from vegetables, namely 1,2 dithiol-3-thione (DTT) and S-methylmethane thiolsulfonate (MMTS), were tested for their chemopreventive activity in the N-methylnitrosourea (NMU)-induced rat mammary tumor model. Each compound was incorporated into the grain-based Teklad 7001 diet and fed to the rats one week prior to initiation with NMU until termination 18 weeks post NMU. DTT was fed at 166 and 500 ppm and MMTS at 200 and 800 ppm. Neither compound exerted a significant inhibitory effect on any index of tumor development including incidence, total tumor, tumor multiplicity, volume or latency. Serum levels of DTT assessed at termination in the 500 ppm DTT group ranged from 10-30 microg/ml. MMTS was undetectable in serum from either MMTS-fed group. The results of this study, using the direct acting carcinogen, NMU, suggest that the chemopreventive effect of thiol-containing compounds may be confined to animal models using carcinogens that require host activation.

Effects of a lycopene-rich diet on spontaneous and benzo[a]pyrene-induced mutagenesis in prostate, colon and lungs of the lacZ mouse

Consumption of lycopene has been associated with reduced risk of prostate cancer. We have investigated the effects of lycopene, fed as a lycopene-rich tomato oleoresin (LTO) at two doses, on in vivo mutagenesis in prostate, colon, and lungs of lacZ mice. Both short-term benzo[a]pyrene (BaP)- induced and long-term spontaneous mutagenesis were monitored. Non-significant inhibition of spontaneous mutagenesis in prostate and colon was observed at the higher dose of LTO, and the observation of inhibition in colon was facilitated by an unusually high spontaneous mutagenesis rate. BaP-induced mutagenesis was slightly inhibited by LTO in prostate. However, enhancement of BaP-induced-mutagenesis was observed in colon and lung. These results indicate that any antimutagenic effects of LTO may be organospecific.

Preventive potential of wheat bran fractions against experimental colon carcinogenesis: implications for human colon cancer prevention

Epidemiological studies suggest an inverse relationship between the intake of dietary fiber, particularly fiber from cereal grains, and colon cancer risk. Animal model assays have demonstrated that the protective effects of dietary fiber on colon cancer development depend on the nature and source of the fiber. Wheat bran (WB) appears to inhibit colon tumorigenesis more consistently than do oat bran or corn bran. This study was designed to determine whether specific WB fractions such as WB fiber, WB lipids, or phytic acid differentially affect colon carcinogenesis in a well-established colon cancer model. In addition, the modulating effect of specific fractions of WB on the activities of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-1 and COX-2 enzymes were assessed in colon tumors as those have been shown to play a role in tumor progression. At 5 weeks of age, groups of male F344 rats were assigned to one of six diets: a high-fat diet containing 10% WB (control diet) and experimental high-fat diets containing 10% dephytinized WB (WB-P), 10% defatted WB (WB-F), 10% dephytinized and defatted WB (WB-PF), 10% WB-PF fortified with 2% bran oil and/or with 0.4% phytate. At 7 weeks of age, all eats except those in the vehicle-treated groups were given two weekly s.c. injections of azoxymethane (AOM) at a dose rate of 15 mg/kg body weight/week. They continued to receive their respective diets until 50 weeks after carcinogen treatment and were then killed. Colon tumors were analyzed for iNOS, COX-1, and COX-2 expression and enzymatic activities. Colon tumors were evaluated histopathologically and classified as adenomas and adenocarcinomas. We found that removal of phytic acid (WB-P) or lipids (WB-F) from WB had no significant effect on colon tumor incidence (% animals with tumors) or multiplicity (tumors/ animal), whereas removal of both phytate and lipids from WB (WB-PF) significantly increased colon tumor multiplicity and volume. Interestingly, WB-PF fortified with excess bran oil or with bran oil plus phytate significantly inhibited colon tumor incidence, multiplicity, and volume; but supplementation of WB-PF with phytate alone had no significant effect on colon tumorigenesis in rats suggesting that lipid fraction of WB possesses tumor-inhibitory properties. Moreover, feeding WB-PF diet significantly increased iNOS, total COX and COX-2 enzyme activities, and iNOS protein expression in colon tumors as compared with wheat bran control diet. Feeding the WB-PF that was fortified with excess bran oil alone or with bran oil plus phytate significantly suppressed the activities of iNOS and COX-2 as well as the expression of iNOS and COX-2 in colon tumors compared with that in rats fed the WB diet or WB-PF diet. The study demonstrates for the first time that the lipid fraction of wheat bran has strong colon tumor inhibitor properties. The exact mechanism(s) by which the lipid fraction of WB inhibits colon carcinogenesis in addition to alteration of iNOS and COX activities remains to be elucidated. Additional studies are warranted to identify biologically active constituents of lipid fraction of WB and their relative role in colon tumor inhibition.

The influence of different varieties of olive oil on N-methylnitrosourea(NMU)-induced mammary tumorigenesis

Several epidemiological and animal model studies suggest that consumption of olive oil, which is rich in the monounsaturated fatty acid, oleic acid (OA, C18:, n-9) may reduce the risk of breast cancer. There are however, a wide variety of olive oils in the marketplace with levels of OA ranging from a low of 50% to a high of 80% OA. The purpose of this rodent model study was to determine whether the level of OA in olive oil is a key determinant of its protective effects. We compared the inhibitory effects among three different types of olive oil containing 54, 70 and 80% OA and 20, 15 and 5% linoleic acid (LA), respectively, corn oil and a store bought olive oil, using the NMU-induced rat mammary tumor model. While little difference was found in total mammary tumor yields, a differential effect was found in the histological type of tumors formed. Olive oil containing 80% OA and 5% LA exhibited the lowest level of adenocarcinomas and the highest level of the more benign adenocarcinoma arising from within a fibroadenoma. While the reasons for this effect remain to be clarified, these results suggest that future studies on the health benefits of olive oil should take into account the type as well as the amount of olive oil.

Effect of intact and isoflavone-depleted soy protein on NMU-induced rat mammary tumorigenesis

Experiments in animal models of carcinogenesis suggest that soy consumption decreases tumor number and incidence. Genistein, an isoflavone which is present in soy at high concentrations, has been considered to be the primary antitumor constituent in soy. In the present study, the N-nitroso-N-methylurea (NMU)-induced mammary tumor model was used as a means to determine whether the chemopreventive effect of soy was attributable specifically to its high content of isoflavones. Five groups of rats (30/group) were fed the following modified AIN-93G diets: group 1, 20% intact soy protein (SP); group 2, 10% SP; group 3, 20% isoflavone-depleted soy protein (IDSP); group 4, 10% IDSP; group 5, the casein-based AIN-93G diet. The SP contained 1.07 and IDSP 0.073 mg genistein/g isolate, respectively. Experimental diets were initiated 1 week prior to NMU administration (at 50 days of age) and continued for another 18 weeks. No significant differences were found among the five groups when assessed in terms of tumor incidence, latency, multiplicity or volume. A trend towards inhibition was observed in both the 20 and 10% SP and IDSP groups when assessed in terms of total tumors/group, tumor volume and latency, but this trend did not achieve statistical significance. The results of this model study do not support the hypothesis that the isoflavone components of soy protein, or soy protein itself, inhibit chemically induced mammary tumor development.

S-allylcysteine, a garlic constituent, fails to inhibit N-methylnitrosourea-induced rat mammary tumorigenesis

Epidemiological and experimental studies suggest that consumption of garlic may protect against several types of cancer. Moreover, a plausible hypothesis has been proposed that the biological effects of garlic can be attributed to the enhancing action of a variety of organosulfur compounds, present in garlic, on hepatic phase II carcinogen detoxification enzymes. We have used the N-methylnitrosourea (NMU)-induced rat mammary tumor model to test the chemopreventive effects of a water-soluble organosulfur constituent derived from aged garlic, S-allylcysteine (SAC). Rats were fed diets supplemented with 666 and 2,000 ppm SAC beginning seven days before initiation with NMU (55 days of age) to termination (18 wk post-NMU), at which time mammary tumors were enumerated. At neither dose did SAC exert an inhibitory effect on any index of tumor development, including incidence, latency, multiplicity, or volume, compared with untreated controls. Weight gains in all groups were similar. Assay of serum SAC levels in supplemented groups indicated that SAC concentrations were beneath the limits of detection of the high-performance liquid chromatography system used. These results contradict previous animal model studies indicating that SAC acts as an inhibitory agent in experimental mammary tumorigenesis; reasons for this discrepancy include the possibility that SAC may exhibit nonlinear dose effects.

Oral enzyme therapy and experimental rat mammary tumor metastasis

Although there has been much interest over the years in the medical use of orally administered proteolytic enzymes, there is considerable controversy about their efficacy against advanced stages of cancer. In light of this, the goal of the present study was to assess the inhibitory effects of different doses of an orally administered porcine pancreas preparation on the growth and metastasis of the R13762 transplantable rat mammary tumor. Five groups of 12 F-344 female retired breeders were inoculated orthotopically with a 2mm3 tumor implant and placed on the following diets: (1) AIN-76A diet + 20% porcine pancreas preparation (PPP); (2) AIN-76A + 20% PPP + 10 mg Mg citrate/rat/day; (3) AIN-76A + 2% PPP; (4) AIN-76A + 2% PPP + 10 mg Mg citrate and (5) AIN-76A only (control). Primary tumor development was monitored for 40 days and following sacrifice, lungs were excised, stained and metastatic foci quantitated. Metastatic foci were sorted into 3 groups based on their radii: small (<1mm), medium (1-3mm) and large (>3mm), and volumes calculated. The oral enzyme preparation had no effect on primary tumor growth or on body weight change over the duration of the study. The percent (incidence) of rats with pulmonary metastases among the five groups were not significantly different. However, among the three size categories of pulmonary foci, decreased incidence was found only in the large (>3mm) volume subset of the 2% PPP group supplemented with Mg++. When assessed in terms of mean number of pulmonary foci/rat, the 20% PPP group exhibited the highest and controls the lowest frequency with the important exception of the 2% PPP + Mg++ group (large volume) which exhibited the lowest frequency of all treatment groups. In general, the presence of Mg++ resulted in marked decreases in mean number of pulmonary foci/rat compared to groups fed PPP without the Mg++ supplement. Similar results were obtained when foci were quantitated in terms of metastatic volume rather than frequency. The results of this laboratory animal study suggest that to show effective inhibition of metastatic dissemination of the R13762 tumor by PPP, lower doses of PPP and larger numbers of animals, to account for the high variability in the model, will be required.

Effect of dietary lycopene on N-methylnitrosourea-induced mammary tumorigenesis

Epidemiological studies suggest protective effects of lycopene-rich foods on several types of cancer, including prostate and gastrointestinal tract. Moreover, an inverse association between serum lycopene concentrations and several types of cancer has been reported. However, few studies have focused on breast cancer, and they have shown little association between lycopene consumption and cancer risk. In this report, we used the N-methylnitrosourea (NMU)-induced rat mammary tumor model to compare the effects of pure lycopene with a lycopene-rich tomato carotenoid oleoresin (TCO) on NMU-induced mammary tumorigenesis. Rats were fed diets supplemented with 250 and 500 ppm crystalline lycopene or TCO beginning seven days before initiation with NMU (55 days of age) to termination (18 wk after NMU). Neither pure lycopene nor lycopene in the form of a mixed carotenoid oleoresin exerted an inhibitory effect on tumor incidence, latency, multiplicity, volume, or total tumors per group compared with unsupplemented controls. Weight gains in all groups were similar. Assay of serum lycopene concentrations in lycopene-supplemented groups indicated that median levels of 7,12,60, and 87 ng/ml were attained in blood of groups supplemented with 250 and 500 ppm lycopene and 250 and 500 ppm TCO, respectively. The results of this animal study are consistent with epidemiological reports indicating that lycopene does not protect against breast cancer.