A powder formulation of measles vaccine for aerosol delivery

Both the mortality rate for measles and the risks associated with injection continue to be high in the developing world. In response to the need for safe, cost-effective vaccine delivery technologies, a powder formulation of measles vaccine has been developed to test the feasibility of administering measles vaccine as an aerosol. The first challenge in aerosol formulation development is to produce fine particles without damaging the activity of the virus or inducing physical changes. In this study, live attenuated measles vaccine is micronized by jet milling to generate particle sizes appropriate for pulmonary delivery (1-5 microm). Milling does not induce detectable physical changes and significant viral potency is maintained. Potency retention of milled vaccine ranges from 31 to 89%, demonstrating that the standard dose of vaccine can easily be achieved. Following size reduction, particles are blended with an inert carrier to improve handling and aerosol dispersion. The measles vaccine formulation is dispersable, as shown by laser light particle size analysis of vaccine aerosols. Thus, evaluation of both the potency retention and the aerosol characteristics of the current formulation clearly demonstrates the feasibility of delivering measles vaccine as a powder aerosol for immunization.

Pharmacological differences between the human and rat vanilloid receptor 1 (VR1)

Vanilloid receptors (VR1) were cloned from human and rat dorsal root ganglion libraries and expressed in Xenopus oocytes or Chinese Hamster Ovary (CHO) cells. Both rat and human VR1 formed ligand gated channels that were activated by capsaicin with similar EC(50) values. Capsaicin had a lower potency on both channels, when measured electrophysiologically in oocytes compared to CHO cells (oocytes: rat=1.90+/-0.20 microM; human=1.90+/-0.30 microM: CHO cells: rat=0.20+/-0.06 microM; human=0.19+/-0.08 microM). In CHO cell lines co-expressing either rat or human VR1 and the calcium sensitive, luminescent protein, aequorin, the EC(50) values for capsaicin-induced responses were similar in both cell lines (rat=0.35+/-0.06 microM, human=0.53+/-0.03 microM). The threshold for activation by acidic solutions was lower for human VR1 channels than that for rat VR1 (EC(50) pH 5.49+/-0.04 and pH 5.78+/-0.09, respectively). The threshold for heat activation was identical (42 degrees C) for rat and human VR1. PPAHV was an agonist at rat VR1 (EC(50) between 3 and 10 microM) but was virtually inactive at the human VR1 (EC(50)>10 microM). Capsazepine and ruthenium red were both more potent at blocking the capsaicin response of human VR1 than rat VR1. Capsazepine blocked the human but not the rat VR1 response to low pH. Capsazepine was also more effective at inhibiting the noxious heat response of human than of rat VR1.

(-)-Spiro[1-azabicyclo[2.2.2]octane-3,5'-oxazolidin-2'-one], a conformationally restricted analogue of acetylcholine, is a highly selective full agonist at the alpha 7 nicotinic acetylcholine receptor

Neuronal nicotinic acetylcholine receptors are members of the ligand-gated ion channel receptor superfamily and may play important roles in modulating neurotransmission, cognition, sensory gating, and anxiety. Because of its distribution and abundance in the CNS, the alpha 7 nicotinic receptor is a strong candidate to be involved in some of these functions. In this paper we describe the synthesis and in vitro profile of AR-R17779, (-)-spiro[1-azabicyclo[2.2. 2]octane-3,5'-oxazolidin-2'-one] (4a), a potent full agonist at the rat alpha 7 nicotinic receptor, which is highly selective for the rat alpha 7 nicotinic receptor over the alpha 4 beta 2 subtype. Preliminary SAR of AR-R17779 presented here indicate that there is little scope for modification of this rigid molecule as even minor changes result in significant loss of the alpha 7 nicotinic receptor affinity.

Does crew resource management training work?

INTRODUCTION

Effective crew resource management (CRM) may play a major role in decreasing the number of accidents and increasing overall safety of air medical programs. The purpose of the study was to compare the responses of crew members, in a variety of situations, who received CRM training and those who did not. The numerical results of the responses were used to evaluate the effectiveness of CRM in increasing crew awareness and promoting team concepts.

METHOD

During a 12-month period, crew members of randomly selected air medical programs (fixed- and rotor-wing) were surveyed by questionnaire. Participants were asked if they had received CRM, effective communication, and team-building training. The next 15 questions pertained to crew interaction/communication in everyday and emergent situations and were scored on a Likert scale (1 = strongly agree and 5 = strongly disagree). A lower total score indicated a greater understanding of team awareness and effective communication.

RESULTS

The mean score of crew members who received the three identified areas of training (initial CRM, team-building, effective communications) (37.96, SD +/- 7.67) was found to be significantly lower than the mean score of those who had received none of the training (44.13, SD +/- 5.0) and P < .05.

CONCLUSION

Based on the results, CRM training increases crew awareness and promotes team concepts in both everyday and emergent situations.

A case-control study confirms that microsatellite assay can identify patients at risk of developing oral squamous cell carcinoma within a field of cancerization

Distinguishing true precursor lesions on the basis of clinical or histological features alone is unreliable but is important so that appropriate intervention can be instigated. Preliminary studies have shown that a microsatellite assay may provide important new prognostic information. To build on these observations, we have performed a case-control study to establish whether we can be confident about incorporating this new information into clinical practice. We have determined the frequency of allelic imbalance (AI) within key chromosomal regions, by matching 39 cases with dysplastic oral lesions that developed a tumor on the same side of the mouth, for as many variables as possible, with controls presenting with similar lesions that did not progress to malignancy when followed for the same period. Our findings confirm that the group that developed tumor had precursor lesions that harbor AI at more loci (P = 0.002). However, no consistent patterns of AI were associated with the three grades of dysplasia: mild, moderate, and severe. One-third of the tumors developed at the same site as the dysplastic lesion and two-thirds at a different site, which revealed that the presence of these aberrations in a dysplastic lesion provided information about the risk of malignant change within a larger field. This suggests that the process of field cancerization is more widespread than previously recognized. On the basis of these findings, we advocate complete excision of all suspicious areas that show AI at two or more key loci, regardless of the degree of dysplasia. However, because the remaining mucosa is also "at risk," these cases should also be targeted to receive dietary advice and chemoprevention, to minimize their risk of tumor formation at a distant site.

Detection of minimal residual cancer to investigate why oral tumors recur despite seemingly adequate treatment

Improvements in surgery and radiotherapy techniques have led to only a modest increase in the 5-year survival rate for patients with head and neck cancer. This is because the pattern of clinical disease is changing, such that locoregional recurrence now accounts for fewer treatment failures, but more patients develop a second primary cancer or distant metastatic disease. In this study, we have used the p53 phage plaque assay, immunocytochemistry, and mutational analysis to assess the contribution of minimal residual cancer and genetic aberrations in clinically normal upper aerodigestive tract mucosa to treatment failure. Eighteen consecutive patients with oral tumors, with conventional clear margins, have been followed for a minimum of 36 months. Molecular assessment identified tumor-positive surgical margins for 6 of 11 assessable patients and additional tumor-positive lymph nodes for three cases. Disseminated malignant cells were detected in the hematopoietic cell compartment for six cases, and one patient had molecular evidence of field cancerization. Locoregional recurrence developed in five patients with tumors harboring a p53 gene mutation; four of these were associated with tumor-positive surgical margins, and one was associated with molecular evidence of field cancerization. Radiotherapy to the primary site did not prevent development of local recurrence when the residual tumor harbored a p53 gene mutation. Three of six cases with a tumor-positive bone marrow aspirate developed distant metastases. These findings reveal that molecular and immunocytochemical detection of minimal residual cancer and field cancerization can help identify patients who may develop locoregional or distant recurrence and justify further studies to evaluate the contribution of these remaining malignant cells to treatment failure.

Psychiatric symptom severity and length of stay on an intensive rehabilitation unit

The purpose of this study was to evaluate the role of psychiatric symptoms in the medical and surgical rehabilitation of patients on an intensive rehabilitation unit and to examine whether psychiatric symptom severity contributes to length of hospital stay (LOS). Forty-four patients (21 men and 23 women) were assessed at admission and before discharge with the Functional Independence Measure (FIM). Subjects were evaluated with the Mini-Mental State Exam (MMSE), the Hamilton Rating Scale for Depression (Ham-D), Positive and Negative Symptom Scale, (PANSS), and Scale for the Assessment of Negative Symptoms (SANS). Thirty-six percent of subjects were cognitively impaired (MMSE < 25), 14% had significant depressive symptoms (Ham-D > 12), and 52% had significant negative symptomatology (PANSS-N > 15). A regression analysis yielded a model of three predictive factors. Gender, the PANSS General subscale, and the SANS Attention subscale accounted for 42.4% of LOS variance. These results indicate that psychiatric symptoms are common in medical rehabilitation inpatients and, together with demographic factors, are associated with increased LOS.

Cost-effectiveness analysis of six strategies for cardiovascular surgery prophylaxis in patients labeled penicillin allergic

The cost-effectiveness of different approaches to antimicrobial prophylaxis for cardiovascular surgery patients labeled penicillin allergic was studied. A decision-analytic model was used to examine the cost-effectiveness of six strategies for antimicrobial prophylaxis in cardiovascular surgery patients at a tertiary care hospital. The strategies consisted of (1) giving vancomycin to all patients labeled penicillin allergic, (2) giving cefazolin to all patients labeled penicillin allergic, (3) giving vancomycin to all patients with a history suggesting an immunoglobulin E (IgE)-mediated reaction to penicillin and cefazolin to patients without such a history, (4) administering a penicillin skin test to patients with a history suggesting an IgE-mediated reaction to penicillin and giving vancomycin to patients with positive results and cefazolin to all others, (5) skin testing all patients labeled penicillin allergic and giving vancomycin to those with positive results and cefazolin to those with negative results, regardless of history, and (6) skin testing all patients and giving vancomycin to those with positive results or a history suggesting an IgE-mediated reaction to penicillin and cefazolin to all others. Giving cefazolin to all patients labeled penicillin allergic was the least expensive strategy but was associated with the highest rate of both anaphylactic and non-life-threatening serious reactions. Selective use of vancomycin in patients with a history suggesting an IgE-mediated reaction to penicillin was associated with an added cost and a slightly lower rate of anaphylaxis. Although skin-testing strategies may decrease both non-life-threatening and anaphylactic reactions, the incremental cost was high. When vancomycin was given to all patients labeled penicillin allergic, the incremental cost was very high. A decision-analytic model indicated that selective use of vancomycin is more cost-effective than indiscriminate use of vancomycin for surgical prophylaxis in cardiovascular surgery patients labeled penicillin allergic.

Bradyzide, a potent non-peptide B(2) bradykinin receptor antagonist with long-lasting oral activity in animal models of inflammatory hyperalgesia

Bradyzide is from a novel class of rodent-selective non-peptide B(2) bradykinin antagonists (1-(2-Nitrophenyl)thiosemicarbazides). Bradyzide has high affinity for the rodent B(2) receptor, displacing [(3)H]-bradykinin binding in NG108-15 cells and in Cos-7 cells expressing the rat receptor with K(I) values of 0.51+/-0.18 nM (n=3) and 0.89+/-0.27 nM (n=3), respectively. Bradyzide is a competitive antagonist, inhibiting B(2) receptor-induced (45)Ca efflux from NG108-15 cells with a pK(B) of 8.0+/-0.16 (n=5) and a Schild slope of 1.05. In the rat spinal cord and tail preparation, bradyzide inhibits bradykinin-induced ventral root depolarizations (IC(50) value; 1.6+/-0.05 nM (n=3)). Bradyzide is much less potent at the human than at the rodent B(2) receptor, displacing [(3)H]-bradykinin binding in human fibroblasts and in Cos-7 cells expressing the human B(2) receptor with K(I) values of 393+/-90 nM (n=3) and 772+/-144 nM (n=3), respectively. Bradyzide inhibits bradykinin-induced [(3)H]-inositol trisphosphate (IP(3)) formation with IC(50) values of 11.6+/-1.4 nM (n=3) at the rat and 2.4+/-0.3 microM (n=3) at the human receptor. Bradyzide does not interact with a range of other receptors, including human and rat B(1) bradykinin receptors. Bradyzide is orally available and blocks bradykinin-induced hypotension and plasma extravasation. Bradyzide shows long-lasting oral activity in rodent models of inflammatory hyperalgesia, reversing Freund's complete adjuvant (FCA)-induced mechanical hyperalgesia in the rat knee joint (ED(50), 0.84 micromol kg(-1); duration of action >4 h). It is equipotent with morphine and diclofenac, and 1000 times more potent than paracetamol, its maximal effect exceeding that of the non-steroidal anti-inflammatory drugs (NSAIDs). Bradyzide does not exhibit tolerance when administered over 6 days. In summary, bradyzide is a potent, orally active, antagonist of the B(2) bradykinin receptor, with selectivity for the rodent over the human receptor. British Journal of Pharmacology (2000) 129, 77 - 86

Immunomagnetic separation for enrichment and sensitive detection of disseminated tumour cells in patients with head and neck SCC

Screening for malignant cells in the blood and bone marrow was introduced as a strategy for the improved detection of tumour spread and may predict the development of distant metastases. The sensitivity of these approaches depends on several factors, including the choice of antibody for immunocytochemistry (ICC) and the number of cells examined. In this study criteria have been defined for scoring cells reactive with a pan-cytokeratin antibody as tumour, by comparing immunostained cells in clinical samples obtained from head and neck cancer patients and a control group without epithelial malignancy. When leucocyte subfractions are prepared by density gradient separation (DGS) from central venous blood obtained from patients with advanced head and neck squamous cell carcinoma (SCC) and screened by ICC, epithelial tumour cells sediment preferentially with the mononuclear cells but may also be detected in the granulocyte (GC) fraction. Some cases were found to have more tumour cells in the GC fraction. Similar results were seen in model experiments. To increase the sensitivity of the ICC approach, the efficiency of positive immunomagnetic selection (IMS) using Dynabeads coated with an antibody recognizing the Ber-EP4 epitope has been compared with negative IMS using anti-CD45 Dynabeads. Tumour cells were recovered from bone marrow aspirates for 2/17 cases using the positive enrichment technique and for 11/17 patients following negative IMS. These findings justify prospective studies incorporating negative IMS to establish the prognostic significance of these disseminated tumour cells for this group of patients.

Relationship between method of detection of breast cancer and stage of disease, method of treatment, and survival in women aged 40 to 49 years

The optimal breast cancer screening program for women 40 to 49 years of age remains controversial. To help assess the value of screening mammography for this age group, we studied the relationship between the method of breast cancer detection and stage, therapy, and survival. Cases of breast cancer diagnosed at Sinai Hospital (Detroit, MI) between January 1985 and December 1994 were reviewed. A total of 181 cases involving 40- to 49-year-old women were available for analysis. The distribution of stage of disease significantly differed among the three methods of detection (P<0.0001). Breast-conserving surgery was more commonly performed in cases detected by screening mammography and clinical breast examination than in cases detected by breast self-examination (P = 0.001). Variation in the stage of disease resulted in improved survival for cases detected by screening mammography and clinical breast examination when compared with those detected by breast self-examination (P = 0.019). Women diagnosed with breast cancer between the ages of 40 and 49 years had earlier stage disease, were more likely to be treated with breast-conserving therapy, and had better survival if their disease was first recognized by screening mammography. Screening mammography has an important role for women of this age.

Location of candidate tumour suppressor gene loci at chromosomes 3p, 8p and 9p for oral squamous cell carcinomas

To help define the location of tumour suppressor genes implicated in the pathogenesis of oral squamous cell carcinoma (SCC), we have used microsatellite assay and restriction fragment length polymorphism (RFLP) analysis to screen 48 primary SCC for allelic imbalance (AI) with 32 polymorphic markers at chromosome 3p, and prepared a detailed deletion map. The finding of a high frequency of AI at specific regions, together with the presence of multiple small interstitial deletions involving these loci, identifies 5 areas at this chromosome arm that may harbour tumour suppressor genes. No sequence aberrations affecting the von Hippel Lindau (VHL) and fragile histidine triad (FHIT) genes, which reside within the candidate tumour suppressor gene areas at this chromosome arm, were identified. A more limited analysis of polymorphic sequences at 8p and 9p supports the existence of at least 2 areas that harbour tumour suppressor genes at 8p and evidence that additional targets for deletion reside centromeric and telomeric to the p16 gene at 9p21.

Is there a risk in being a good Samaritan?

It's Nursing Week and you are at a booth in a busy shopping mall. After spending a couple of hours talking with people, answering questions and taking blood pressure readings, you start to sip a well-earned cup of coffee. You glance down the mall and observe a middle-aged man suddenly clutch at his chest and fall to the floor. You alert your colleagues to call 911 as you run down the mall to do what you can. You reach the man, announce, "I know CPR," and initiate resuscitation. You have just spent an invigorating day on the ski slopes. As you drive home, you are horrified to see a car spin out of control and roll over into the ditch a couple of car lengths ahead of you. Suddenly you face a dilemma. You are an experienced nurse who wants to help and yet, lurking in the back of your mind, there is the nagging fear that you could be sued. You wonder if are you legally obligated to stop and assist. Could you be liable if you fail to do so?

Molecular characterisation of cloned bradykinin B1 receptors from rat and human

This report describes the characterisation of cloned rat and human bradykinin B1 receptors in African green monkey kidney fibroblast (Cos-7) cells. A ligand binding assay with [3H]des-Arg10-kallidin was used to compare their pharmacology with respect to known bradykinin B1 and B2 receptor ligands. In addition, the pharmacology of T-kinin and its' derivative des-Arg11-T-kinin was investigated. The cloned rat receptor had a similar pharmacology to that of the recently described mouse receptor and differs from that described for the human receptor. The rat receptor had a higher affinity for des-Arg11-T-kinin than the human receptor. These differences in pharmacological properties may relate to the presence of T-kinin, bradykinin and their des-Arg derivatives as the major physiological peptides in rat and the predominance of kallidin and its derivatives in human. We confirm that the rat bradykinin B1 receptor gene is organised in a two exon structure and differs from the human gene which has a three exon structure and we further examine the inducible expression of this gene in a wide range of tissues using Northern blotting.

Patient-specific mutation databases for oral cancer

Development of databases, summarising the genetic events associated with oral squamous cell carcinoma (SCC), should increase our understanding of the molecular basis of these lesions. Additionally, databases will help establish whether different cancer subtypes show different growth characteristics, because the multistage carcinogenic process is different in the various tumour subtypes. This new knowledge may also provide new prognostic information, as these aberrations represent fundamental biological characteristics of each tumour. To assess the value of incorporating the results from loss of heterozygosity (LOH) analysis into patient-specific mutation databases, we have carried out microsatellite analysis with 52 polymorphic markers at 13 key chromosomal regions implicated in the pathogenesis of head and neck cancers. Altered expression of the Rb, p53 and DCC tumour suppressor genes has also been studied by immunohistology. Our results shed light on the different pathways that lead to cancer and reveal that a variety of different patterns of allelic imbalance (AI) were detected at all TNM stages, reflecting the different clinical behaviour that tumours classified as being of the same TNM stage may exhibit. Summarising the level of genetic damage as a fractional allelic loss (FAL) score and the presence of AI at 3p22-26, 3p14.3-12.1 and 9p21 was found to be a better predictor of outcome than the TNM system. This finding suggests that molecular data can be incorporated into conventional staging systems to provide more accurate prognostic information for this group of patients.

The prognostic significance of allelic imbalance at key chromosomal loci in oral cancer

Forty-eight primary oral squamous cell carcinomas (SCC) were screened for allelic imbalance (AI) at 3p24-26, 3p21, 3p13, 8p21-23, 9p21, 9q22 and within the Rb, p53 and DCC tumour suppressor genes. AI was detected at all TNM stages with stage 4 tumours showing significantly more aberrations than stage 1-3. A factional allelic loss (FAL) score was calculated for all tumours and a high score was associated with development of local recurrence (P = 0.033) and reduced survival (P = 0.0006). AI at one or more loci within the 3p24-26, 3p21, 3p13 and 9p21 regions or within the THRB and DCC genes was associated with reduced survival. The hazard ratios for survival analysis revealed that patients with AI at 3p24-26, 3p13 and 9p21 have an approximately 25 times increase in their mortality rate relative to a patient retaining heterozygosity at these loci. AI at specific pairs of loci, D3S686 and D9S171 and involving at least two of D3S1296, DCC and D9S43, was a better predictor of prognosis than the FAL score or TNM stage. These data suggest that it will be possible to develop a molecular staging system which will be a better predict of outcome than conventional clinicopathological features as the molecular events represent fundamental biological characteristics of each tumour.

Dry powder inhalation as a potential delivery method for vaccines

Measles vaccine is administered to millions of children annually via a percutaneous injection. There are, however, compelling reasons to search for alternative routes of administration, especially in mass vaccination campaigns. Two key factors are (1) decreased stability of the vaccine upon reconstitution and, (2) the potential risks of contamination associated with needles. Dura has developed a unique inhaler that can deliver a powder dose via the pulmonary route for local or systemic action. The breath-actuated Spiros inhaler uses electromechanical energy to aerosolize and deliver a consistent dose over a wide range of inspiratory flow rates. To achieve alveolar (deep lung) deposition for subsequent systemic absorption, dry-powder vaccine is size reduced to a mass median diameter between 1 and 5 microns. Small vaccine particles are blended with an inert carrier to improve dispersion. Measles vaccine formulated as a powder blend may be more thermostable than existing reconstituted formulations. The Spiros technology is available in three powder storage platforms. Two of these formats are designed specifically for moisture and/or light sensitive compounds and may be particularly suitable for delivery of measles vaccines in mass campaigns because their design (1) eliminates the need for powder reconstitution, and (2) reduces the risk of contamination.

Electroencephalographic responses to alcohol challenge in Native American Mission Indians

BACKGROUND

Native Americans have some of the highest rates of alcohol abuse and dependence, yet potential central nervous system risk factors responsible for the problem drinking seen in some tribes remain relatively unknown.

METHODS

Background electroencephalographic (EEG) variants and response to alcohol were investigated in 48 Native American Mission Indian men between 18 and 25 years old.

RESULTS

Subjects with 50% or greater Native American heritage had a significantly higher proportion of low-voltage EEG variants. Within this sample of Mission Indian men, however, a family history of alcohol dependence was associated with a greater incidence of high voltage alpha EEGs. Mission Indian men also evidenced a "less depressant, more stimulating" response to alcohol as quantified by less alcohol-induced reductions in alpha, greater EEG stability, and increased alcohol-induced beta activity.

CONCLUSIONS

These findings demonstrate that certain genetically regulated EEG variants that have been previously associated with risk for alcoholism in Caucasians may also be more common in these Mission Indian men. Additionally, EEG measures of response to alcohol do not provide support for the commonly held idea that Indians are more sensitive to the depressant effects of alcohol.

A prospective controlled multicentre study of clarithromycin in pregnancy

Clarithromycin is a relatively new macrolide antibiotic with an action spectrum similar to that of erythromycin. Its main indications for use are for upper and lower respiratory and skin and soft tissue infections. Little is known about its safety in pregnancy, although animal reproductive studies found an increased rate of cardiovascular anomalies, cleft palate, and embryonic loss. Human data, limited to case reports and one small uncontrolled study, cannot allow evidence based counseling of pregnant women who were exposed to the drug before finding out they were pregnant. Pregnant women who had been counseled on the use of clarithromycin by five centers, were matched for age, smoking, and alcohol use with a control group of pregnant women who were exposed to nonteratogenic antibiotics. A total of 157 women were followed up. Of these, 122 were exposed to the drug in the first trimester. There were no significant differences found between the two groups in the rates of major and minor malformations; 2.3 versus 1.4% for major (p = 0.86) and 5.4 versus 4.9% for minor (p = 0.96). Spontaneous abortion rates in the exposed group was significantly different, higher (14%) than in the control group (7%) (p = 0.04). This first prospective controlled study of exposure to clarithromycin in pregnancy suggests that this agent does not increase the rate of major malformations above the baseline risk of 1-3%. The higher rate of reported spontaneous abortions, although still within the expected baseline rate, may warrant further study.

Toxoplasmosis

QUESTION

A 28-year-old patient is 3 months pregnant with her first child. She has heard about toxoplasmosis from her friends and asks if it is safe to keep her cat. How should I reply?

ANSWER

Your patient does not have to give up her cat. She should be encouraged to take primary preventive measures. If toxoplasmosis serology is performed, a baseline should be done as early as possible with serial follow up in the second and third trimesters.

Determinants of P3 amplitude and response to alcohol in Native American Mission Indians

Native Americans have some of the highest rates of alcohol abuse and dependence, yet potential biological risk factors associated with the problem drinking seen in some tribes remain relatively unknown. The amplitude of the P3 component of the event-related potential (ERP) is perhaps the most studied electrophysiological "marker" of potential vulnerability to alcohol dependence, yet it has not been investigated in Native Americans. Forty-seven, non-alcohol-dependent Native American Mission Indian men between the ages of 18 and 25 years participated in the study. ERPs were collected at 60 minutes following both alcohol (0.56 g/kg) and placebo intake. No relationship was found between P3 amplitude and degree of Native-American heritage (NAH), or family history (FH) of alcohol dependence. The results of this study did, however, replicate previous findings that the P3 component of the ERP is sensitive to the effects of alcohol. A reduction in the P3a component across the scalp was found in these Native American men following alcohol when compared with placebo ingestion. P3 response to alcohol, although not influenced by a subject's NAH or FH, was influenced by the presence of a polymorphism in the alcohol metabolizing enzyme alcohol dehydrogenase (ADH). Men with an ADH2 x 3 allele had significantly higher amplitude P3 components at placebo and also demonstrated more alcohol-induced reductions in P3 amplitude than men with ADH2 x 1 alleles only. In addition, individuals with low P3 amplitude in the placebo condition had less of a reduction or an actual increase in P3a and P3b amplitudes following alcohol intake. Given that a less intense response to alcohol has been associated with greater risk for the development of alcohol-related problems, these data suggest the presence of certain biological variables within this Native American population that may confer both risk and protection for the future development of alcohol dependence.

Allelic imbalance at chromosomal loci implicated in the pathogenesis of oral precancer, cumulative loss and its relationship with progression to cancer

A microsatellite assay was used to screen 31 potentially malignant oral lesions presenting as leukoplakia and erythroplakia, with histological evidence of dysplasia, for genetic abnormalities at loci which frequently show allelic imbalance when oral squamous cell carcinomas (SCC) are examined. The microsatellite and restriction fragment length polymorphism (RFLP) markers selected were at 3p21, 8p21-23, 9p21 and included sequences within the Rb (13q14.2), p53 (17p13.1) and DCC (18q21.1) tumour suppressor genes. 8 patients subsequently developed an invasive tumour at the same site, or within 2 cm of the premalignant lesion. A further 8 patients developed SCC at a distant site. Seventy-seven per cent (24/31) of these potentially malignant lesions showed allelic imbalance (AI) and 55% (17/31) of cases showed microsatellite instability (msi). The probability of developing SCC was much greater for patients with lesions showing AI at two or more relevant loci (P = 0.008 by the logrank test) than the group with AI at fewer loci. The estimated probability of development of SCC in this group by 5 years was 73% (95% Cl: 50-92%). This suggests that determining the number of genetic abnormalities in a potentially malignant lesion can help identify patients with true precancers who should be followed closely to ensure that they receive chemoprevention and appropriate advice to limit risk factors, and to allow the early detection of invasive lesions.