Maryland dentists' attitudes regarding tobacco issues

Due to increased national interest in tobacco intervention roles for oral health professionals, a survey of Maryland dentists' attitudes toward tobacco issues was conducted. A convenience sample of 700 members of the Maryland State Dental Association was drawn from the total membership list (N = 2200). A 30% response rate was obtained. Subjects were mailed a twelve-item questionnaire that elicited primarily attitudinal information. Results revealed that 54.3% of the subjects never smoked, 39% formerly smoked and 6.1% currently smoke. Smoking behavior was associated with numerous attitudinal variables including dentistry's role in promoting tobacco-use cessation. Relatively few of the respondents were aware of federal initiatives regarding the oral health professions' roles in intervention. Less than half viewed tobacco-use cessation interventions as a practice builder, yet 82.1% believe cessation advice is the dentist's responsibility. Respondents' interest in obtaining free training in tobacco-use interventions was positive and was significantly related to several attitudinal variables. Dentists in Maryland appear to appreciate their role in tobacco-use interventions at both the clinical and community levels. However, they exhibit ambivalence regarding the economic value of office interventions and the need for formalized training. Maryland dentists also need to be apprised of federal initiatives concerning tobacco use interventions.

Voluntary exercise and experimental mammary cancer

The results of these studies indicate that voluntary activity suppresses the development of chemically and virally induced primary mammary tumors in rats and mice fed high-fat diets. These diets were chosen to mimic the current U.S. fat consumption of approximately 40% of calories as fat. It remains to be seen if activity exerts a similar suppressive effect on animals fed their customary low-fat diet (10% calories as fat). In general, the activity profiles of the female Fischer F-344 and Sprague-Dawley rat and the C3H/o mu j mouse exhibited a similar pattern with an early peak followed by a gradual plateau over time. The effects of activity on body fat composition showed a trend toward a decreased percent of body fat when compared to sedentary animals but a statistically significant decrease was found only in the F-344 female rat. In the DMBA model, carcinogen dose did alter outcome parameters. For example, time to first tumor was extended under low- but not high-DMBA conditions, and, conversely, tumor multiplicity was significantly decreased in the high- but not low-DMBA group. In the NMU model, an inverse association was found between the amount of activity and tumor incidence. A similar association was not found with the DMBA model. The reason for this is uncertain, but further analysis in terms of other parameters such as total tumor number may shed more light on this discrepancy. The suppressive effect of activity on the MMTV-induced mouse mammary tumor is of particular interest since it raises the possibility that activity may exert effects on the process of provirus insertion, and/or oncogene activation--an area of great potential promise in cancer prevention. Activity appeared to enhance the volume and to a lesser degree the number of metastatic foci in the lungs of F-344 retired breeders under high-fat but not medium-fat conditions. In addition, the most active animals in the high-fat group exhibited the greatest volume of metastases. These results, together with those in the NMU model, point to the critical importance of the quantity of voluntary activity an animal engages in and its relation to both primary and secondary cancer prevention. They imply that beyond a certain point of either frequency or intensity, the beneficial effect of exercise may be nullified by competing deleterious effects. The metastases study has also brought to light the importance of dietary fat as a potential intervening variable.(ABSTRACT TRUNCATED AT 400 WORDS)

Incorporation of 2-fluorohistidine in murine protein in vivo

The tissue distribution and time course of incorporation into acid insoluble (bound) and acid soluble (free) fractions of [3H]2-fluorohistidine is compared to that of U[14C]Histidine in mouse tissues in vivo. The cycloheximide-sensitive incorporation of 2-FHis is between 9 and 17 percent of that of His. Unlike [14C]His a major fraction, approximately 90% at 72 hrs, of isotope derived from [3H]2-FHis remains in tissues for a prolonged period in an acid soluble form. The excretion of isotope derived from [14C]His (T1/2 = 5 hr) is more rapid than from [3H]2-FHis (T1/2 = 11.4 hrs). 2-FHis, at doses from 100 to 250 mg/kg produce a reversible inhibition of growth in mice.

Modulation of N-nitrosomethylurea induced mammary tumorigenesis by dietary fat and voluntary exercise

The effect of dietary fat and exercise on N-nitrosomethylurea [NMU:CAS:684-93-5]-induced mammary tumorigenesis in female F344 rats was investigated. Rats were fed the NIH-07 diet until NMU administration on day 50 of age, when they were transferred to four treatment groups. Three sedentary groups were fed either high-fat (20% wt/wt), medium fat (10%) or low fat (5%) diets (HF, MF, LF, respectively), and a fourth group was fed a HF diet but allowed free access to an activity wheel (HFEX). Tumor yields among the three sedentary groups were significantly greater in the HF and MF groups when compared to the LF group. Voluntary exercise reduced tumor yields and delayed time of tumor appearance in HFEX animals to levels similar to those found in LF sedentary animals. Animals with voluntary access to exercise wheels averaged between 1.03 and 2.85 miles/day, consumed more food (+ 18%) and exhibited greater weight gain (+ 13%) than their sedentary counterparts. No differences in weight gains were detected among the HF, MF, and LF groups, despite widely varying amounts of fat intake. Body composition studies indicated that body fat content was not influenced by the quantity of fat consumed in the diet, but was significantly reduced by voluntary exercise (-20%). Since exercise and fat intake have been associated with alterations in endocrine status, circulating bioactive and immunoactive prolactin were assessed at termination. No significant changes were found in either form of prolactin among the four experimental groups, casting doubt on mediation by this pituitary hormone.

Direct electrophilic fluorination of tyrosine in dermorphin analogues and its effect on biological activity, receptor affinity and selectivity

In a preliminary communication we reported [(Tetrahedron Lett. 31, 619 (1990)] that acetyl hypofluorite can be used efficiently to introduce fluorine regiospecifically (ortho to OH) into the phenolic ring of tyrosine-containing peptides. This procedure has been applied to the fluorination of a number of mu-selective opioid peptides derived from dermorphin. While the procedure can be used even when the side chains of Arg, Lys, and Tyr are left unprotected, the sulfoxide of a Met(O)-containing analogue was oxidized to sulfone faster than fluorination of the phenolic ring. This method can also be used when the peptide is attached to Merrifield resin. Thus, Tyr(3-F)-D-Ala-Phe-Gly-NH2 and Tyr(3-F)-D-Arg-Phe-Lys-NH2 (F-DALDA) have been prepared, purified, and characterized. Affinities of these fluorinated peptides for both mu- and delta- opioid receptors are reduced (two- to nine-fold) relative to their nonfluorinated analogues, but their selectivity for mu-opioid receptors is not significantly altered. Similarly, the in vitro biological potencies (GPI and MVD assays) of the fluorinated analogues are reduced (two- to seven-fold) relative to their nonfluorinated parent peptides. Thus, F-DALDA, which has high affinity (Ki mu = 15.2 nM) and selectivity (Ki delta/Ki mu = 5390) for mu-opioid receptors, has potential use in biochemical studies which utilize 19F or 18F- labeled compounds.

Patients' perceptions related to the use of infection control procedures

An assessment was made of the public's attitudes toward infection control techniques utilized in dentistry. Five hundred and nine adults in the State of Maryland responded to a detailed telephone survey in late 1989. Respondents reported that most of their dentists (87.0%) wore gloves and 69.8% of the respondents preferred gloves. Respondents who were most concerned about AIDS also preferred the dentist to wear gloves (92.6%). Respondents received information about AIDS from various sources, chief of which were newspapers or magazines (29.0%) and television (27.3%) but 80.9% would read pamphlets on AIDS if they were available in the dentist's office. Finally, few (13.1%) had ever discussed AIDS with their dentist but most (78.6%) would be comfortable doing so. This study demonstrated that the public accepts and welcomes the use of barrier protection by dentists. The public also is willing to discuss AIDS and infectious diseases with dentists and would read AIDS information supplied by dentists. Given the continued spread of the AIDS epidemic, it is increasingly important for dentists to educate the public about AIDS as well as about the continued safety of the dental office. The public is receptive to this education.

Modulation of N-nitrosomethylurea-induced mammary tumor promotion by dietary fiber and fat

A test of the anticancer effects of dietary fiber was conducted using the N-nitrosomethylurea (NMU)-induced rat mammary tumor model. Starting 3 days after NMU treatment, four different groups of F344 rats (30 rats in each group) were fed as follows: Group 1 received a high-fat diet; group 2, a high-fat plus fiber diet (soft white wheat bran, 10% wt/wt); group 3, a low-fat diet; and group 4, a low-fat plus fiber diet. The rats remained on these diets for 15 weeks. Tumor incidence in group 1 was 90% compared with 66% in group 2 (P less than .001). Tumor incidence in group 3 was 63% compared with 47% in group 4 (P greater than .4). These results show that supplemental dietary fiber exerts an inhibitory effect on the promotional phase of NMU-induced mammary carcinogenesis in rats when fed a high-fat but not a low-fat diet. To test whether fiber may exert its antipromoting effect by reducing circulating estrogens, serum 17 beta-estradiol was assayed. No changes were observed in serum 17 beta-estradiol levels among the four groups, suggesting that the protective effect of fiber in this animal model is not mediated by a fiber-induced reduction of circulating 17 beta-estradiol.

Attitudes of dentists concerning hepatitis and hepatitis vaccination

Many dentists do not understand that hepatitis B infection poses a greater threat to their lives and health than acquired immunodeficiency syndrome (AIDS). This survey examined the attitudes and beliefs of dentists concerning hepatitis and hepatitis vaccination. Many dentists have not been vaccinated. The reasons for avoiding vaccination are examined.

Dietary N-3 fatty acids do not affect induction of Ha-ras mutations in mammary glands of NMU-treated rats

The purpose of this study was to determine whether dietary n-3 polyunsaturates (PUFA) can affect the frequency of N-nitrosomethylurea (NMU)-induced Ha-ras mutations in virgin female F344 rat mammary glands. Two groups of 15 rats each were fed isocaloric diets containing either 23% w/w corn oil or corn oil plus menhaden oil (1:1) at starting 14 d before NMU administration (day 50 of age) and continuing for 13 wk. Mammary gland samples were taken serially at 3, 5, 9, and 13 wk post-NMU treatment. Total cellular DNA was isolated and analyzed by a newly devised enriched amplification procedure that involves predigestion of normal Ha-ras alleles at codon 12, amplification of the mutant alleles, and restriction fragment length polymorphism analysis. Selective amplification enabled the detection of Ha-ras mutations as early as 3 wk post-NMU treatment. Approximately 40-50% of all glands and 75% of all rats tested had the Ha-ras codon 12 mutation. No significant differences were found between the two dietary groups at any time point, indicating that the mammary tumor-inhibiting effect of n-3 PUFA is probably not exerted at the level of the Ha-ras activation step in NMU tumorigenesis.

Selective cardiorespiratory activity of an iodinated analog of thyrotropin-releasing hormone (TRH)

The biological activity of thyrotropin-releasing hormone (TRH) and its analogs 4(5)-I-Im-TRH and 2,4(5)-I2-Im-TRH was assessed by means of their effects on: 1) the mean arterial pressure (MAP), 2) heart rate (HR), 3) ventilation minute volume (MV), 4) contractility of the rat duodenum, and 5) concentrations of thyrotropin (TSH) or prolactin (PRL) in serum. Also their binding to TRH-receptors in brain homogenates was studied. In urethane-anesthetized rats TRH ICV increased MAP, HR and MV. 4(5)-I-Im-TRH was equally as active as TRH on HR and MV but a significant elevation in MAP was observed only at a dose 100-fold to that of TRH. However, the maximal responses of 4(5)-I-Im-TRH and TRH did not differ. In conscious rats, TRH 1A elevated MAP and HR but 4(5)-I-Im-TRH was active on MAP only. 2,4(5)-I2-Im-TRH was devoid of cardiorespiratory activity. TRH dose-dependently inhibited the contractions of the rat duodenum while the iodinated analogs lacked such an activity. To induce a significant release of TSH several hundred times more of 4(5)-I-Im-TRH and over 1000 times more of 2,4(5)-I2-Im-TRH were needed as compared to TRH. The iodoanalogs elevated PRL levels only at doses 2000-fold higher than those of TRH. The iodoanalogs displaced [3H][3-Me-His2]TRH [( 3H]MeTRH) from its binding sites at concentrations about 1000 times higher than those of TRH. Substitutions of the histidyl moiety of TRH in 4(5)-I-Im-TRH and 2,4(5)-I2-Im-TRH resulted in substantial loss of the endocrine activity. While the di-iodinated analog was practically devoid of any biological activity the monoiodinated analog exerted similar cardiorespiratory activity to that of TRH.

Norvaline2-TRH: binding to TRH receptors in rat brain homogenates

Norvaline2-thyrotropin-releasing hormone ([Nva2]TRH) has been described as a thyrotropin-releasing hormone (TRH) analog with no thyrotropin (TSH)-releasing capacity but enhanced analeptic activity compared with TRH, as shown by the reversal of haloperidol-induced catalepsy. We have evaluated the receptor-binding properties of [Nva2]TRH in homogenates of rat anterior pituitary, hypothalamus, brainstem and cortex tissue, using [3H]TRH and [3H][3-Me-His2]TRH as radioligands. Apparent Ki values at high affinity TRH-binding sites, labelled predominantly by [3H][3-Me-His2]TRH, ranged from 17.0 to 36.9 microM in all tested regions. Additionally, [Nva2]TRH was shown to compete with [3H]TRH at low affinity TRH-binding sites with similar affinities. It is concluded that the loss of TSH-releasing activity of [Nva2]TRH appears to be due to a drastic reduction in binding affinity to the high affinity TRH receptor subtype. Its analeptic activity, however, may be mediated by low affinity TRH binding sites which are predominantly labelled by [3H]TRH or by yet unidentified mechanisms.

Do dietary monounsaturated fatty acids play a protective role in carcinogenesis and cardiovascular disease?

Evidence gleaned from epidemiology, nutritional anthropology, and laboratory animal studies is cited to support the hypothesis that the metabolism of 20th century man is poorly adapted to the present day high-fat, high-saturated fat Western diet, and that the emergence of heart disease and cancer as the major killing diseases in modern industrial societies may have resulted, at least in part, from the inability of our ancient metabolic heritage, adapted over eons to a low-fat, high-monounsaturated fat diet, to cope with our modern Western diet--a diet of unusually high caloric density that appeared only recently (approximately 250 years ago) in the 100,000+ year evolutionary history of Homo sapiens.

Knowledge, attitude, and outlook toward dentistry: their affect on sealant use and other related variables

The dentist's knowledge about sealants, his attitude about the efficacy, safety, and cost effectiveness of sealants, and his general outlook towards dentistry as a profession were examined in a recent nationwide study of sealant use. Thirty-five hundred general dentists and 500 pediatric dentists were surveyed by a mail questionnaire with a response rate of 37.6% for generalists and 61.2% for pediatric dentists. Numerous moderate correlations were found. Both groups' Knowledge and Attitude scale scores were moderately correlated with sealant use as measured by the respondents' estimation of the percentage of their patients, age 18 and under, receiving sealants. Moderate correlations for both dentist groups also surfaced between Attitude and Knowledge as well as Attitude and Outlook but not between Knowledge and Outlook. Attitude in both groups correlated moderately with respondent scales entitled Preventive Orientation, Patient Influence, and Auxiliary Factors. For generalists, knowledge also correlated moderately with Sealant Awareness and Patient Influence while, for pediatric dentists, knowledge correlated moderately with Patient Influence only. While there was no significant difference between generalist and pediatric dentist outlook scale scores, pediatric dentists showed a significantly more positive attitude and greater knowledge about sealants than did generalists. It was suggested, therefore, that improvement of practitioners attitude and knowledge about sealants might influence sealant use.

Receptor binding of fluorinated histidine analogs of thyrotropin-releasing hormone in various regions of the rat brain

Binding properties of [4(5)-fluoro-imidazole-His2]-TRH (4(5)-F-TRH), [2-trifluoromethyl-imidazole-His2]-TRH (2-CF3-TRH) and [4(5)-trifluoromethyl-imidazole-His2]-TRH (4(5)-CF3-TRH), three novel TRH analogs, have been evaluated in rat pituitary, hypothalamus, brainstem and cortex tissue. 4(5)-F-TRH, previously shown to elicit arterial pressor responses and prolactin release similar to those of TRH, binds to TRH receptors with low, micromolar affinity (Ki = 7.5-13.5 microM). 2-CF3-TRH, an analog of less cardiovascular but increased prolactin-releasing activity, shows Ki values of 3.3-4.9 microM. 4(5)-CF3-TRH, which shows comparable biological activity to 2-CF3-TRH, demonstrates a binding affinity which is virtually nonspecific (Ki = 0.39-1.01 mM). It is therefore concluded that the biological effects of these analogs are mediated either through low affinity TRH binding sites not recognized by [3H][3Me-His2]-TRH or through mechanisms not involving TRH receptors as such.

Chemoprevention of experimental mammary carcinogenesis by the synthetic organoselenium compound, benzylselenocyanate, in rats

The effect of the dietary organoselenium compound, benzylselenocyanate (BSC) along with its sulphur analogue, benzylthiocynanate (BTC) and sodium selenite (Na2SeO3), on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary carcinogenesis was examined in female Sprague-Dawley rats during the initiation phase of carcinogenesis. Semipurified diets containing 25 p.p.m. of BSC and 25 p.p.m. BTC, and 4 p.p.m. Selenium as Na2SeO3 in drinking water were given to 5-week-old rats for 3 weeks starting 2 weeks before, during and until 1 week after carcinogen treatment. At 7 weeks of age animals were given a single dose of DMBA (10 mg) in 1 ml olive oil by oral intubation. One week after DMBA treatment, the groups receiving BSC- and BTC-supplemented diets were transferred to the unsupplemented standard diets and the group of rats receiving Na2SeO3 in drinking water was transferred to regular tap water for the duration of the experiment. The results indicate that the rats receiving BSC in their diet showed a highly significant inhibition of tumor incidence and tumor multiplicity as well as a prolonged latency period when compared to the group fed the control diet. Neither BTC nor Na2SeO3 had any effect on the subsequent development of mammary tumors. These results indicate that dietary BSC inhibits mammary tumor incidence during the initiation phase of carcinogenesis and is a considerably more potent inhibitor than its sulphur analogue BTC and inorganic selenium. This is the first report that demonstrates the inhibition of mammary carcinogenesis by a synthetic organoselenium compound.