Induction and maintenance of ethanol self-administration in cynomolgus monkeys (Macaca fascicularis): long-term characterization of sex and individual differences.

BACKGROUND: Investigations of oral ethanol self-administration in nonhuman primates have revealed important parallels with human alcohol use and abuse, yet many fundamental questions concerning the individual risk to, and the biological basis of, excessive ethanol consumption remain unanswered. Moreover, many conditions of access to ethanol in nonhuman primate research are largely unexplored. This set of experiments extends within- and across-session exposure to ethanol to more fully characterize individual differences in oral ethanol self-administration. METHODS: Eight male and eight female adult cynomolgus monkeys (Macaca fascicularis) were exposed to daily oral ethanol self-administration sessions for approximately 9 months. During the first 3 months, a fixed-time (FT) schedule of food delivery was used to induce the consumption of an allotted dose of ethanol in 16-hr sessions. Subsequently, the FT schedule was suspended, and ethanol was available ad libitum for 6 months in 16- or 22-hr sessions. RESULTS: Cynomolgus monkeys varied greatly in their propensity to self-administer ethanol, with sex and individual differences apparent within 10 days of ethanol exposure. Over the last 3 months of ethanol access, individual average ethanol intakes ranged from 0.6 to 4.0 g/kg/day, resulting in blood ethanol concentrations from 5 to 235 mg/dl. Males drank approximately 1.5-fold more than females. In addition, heavy-, moderate-, and light-drinking phenotypes were identified by using daily ethanol intake and the percentage of daily calories obtained from ethanol as criteria. CONCLUSIONS: Cynomolgus monkeys displayed a wide intersubject range of oral ethanol self-administration with a procedure that used a uniform and prolonged induction that restricted early exposure to ethanol and subsequently allowed unlimited access to ethanol. There were sex and stable individual differences in the propensity of monkeys to consume ethanol, indicating that this species will be important in characterizing risk factors associated with heavy-drinking phenotypes.

Photographic analysis of facial changes associated with maxillary expansion.

Previous studies on the effects of surgical and rapid palatal expansion have been largely based on general skeletal and dental findings ascertained from radiographs and casts. The aim of this study was to measure and compare the soft tissue changes of the face during the expansion process and to determine the stability of any changes 1 year later. The sample consisted of 44 patients with unilateral or bilateral posterior crossbites. Twenty-four of the patients required a surgically assisted expansion procedure, and a second group of 20 patients were treated with orthopedic expansion. Ten measurements were made from standardized frontal facial photographic slides at 5 intervals of treatment: initial, bond appliance, stop expansion, debond appliance, and 1 year retention. Differences over time between the surgical and nonsurgical groups were analyzed by a 2 way multivariate analysis of variance (MANOVA) and post hoc t tests. Differences between initial and 1 year retention were found in the nasal widths (P <.001) of both surgical and nonsurgical groups. Other significant changes and trends were discussed.

Confirmation of nasogastric tube placement by colorimetric indicator detection of carbon dioxide: a preliminary report.

BACKGROUND: Inadvertent insertion of nasogastric tubes into the trachea and distal airways is reported to range from 0.3% to 15% of insertions. Critically ill, mechanically ventilated patients are at a higher risk for such complications, some of which can be fatal. OBJECTIVE: This preliminary prospective clinical investigation was designed to determine whether a colorimetric carbon dioxide (CO2) indicator device (Easy-Cap, Nellcor, Inc., Hayward, CA) attached to the proximal end of a small bore feeding tube (FT) would reliably discriminate between those tubes passed into the airways and those passed into the alimentary tract. METHODS: Ten critically ill, mechanically ventilated trauma patients requiring a FT insertion were evaluated. An Easy-Cap device was adapted to the proximal port of each FT. Each patient had one tube inserted per the nasogastric route and then another through the endotracheal tube while the Easy-Cap was observed for color changes consistent with the presence of CO2. RESULTS: All transtracheal insertions showed immediate and unambiguous color changes consistent with the presence of CO2. None of the nasogastric insertions resulted in indicator color changes and all were confirmed with radiography (sensitivity 100%, specificity 100%, accuracy 100%). CONCLUSIONS: This preliminary report suggests colorimetric CO2 detection accurately and reliably identifies transtracheal FT insertion.

Fast measurements of transmission of erythema effective irradiance through clothing fabrics.

For efficiently measuring ultraviolet transmission through clothing materials for a large number of samples, an automated measuring system with a broad-band method has been built and calibrated against a spectroradiometer based instrument. The apparatus can be used to test 60 samples in 25 min. A selection of clothing materials of known composition, weave, color and state have been tested, using the broad band method and the automated measuring system together with a solar ultraviolet simulator. Variations of about eleven times for different weave structure, about two times in the ultraviolet transmittance for different colors, and about 20 times for some stretched samples were observed. For wet conditions, an increment in ultraviolet transmittance for cotton and lycra materials and a decrement for polyester and polyester(65%)/cotton(35%) were also observed.

Laser-aided degradation of composite resin.

The removal of residual composite resin after debonding orthodontic brackets often creates surface scratches, enamel loss, and enamel tearouts. If the Nd:YAG laser could selectively degrade the resin without damaging the underlying tooth structure, these problems might be eliminated. The purpose of this study was to determine the effectiveness of the Nd:YAG laser in degrading composite resin within a time frame that will not cause pulpal damage. Minimal lasing times and optimum frequencies were determined by testing the compressive strengths of resin cylinders exposed to laser radiation for 2, 3, 5, 10, or 15 seconds at frequencies of 60, 80, or 100 Hz. The optimum condition was determined to be a 3 second lasing time at a frequency of 100 Hz. Cylinders of composite resin were divided into four groups consisting of: (1) resin, (2) resin with a laser enhancing dye, (3) resin lased for 3 seconds at 100 Hz, and (4) resin with the dye which was lased for 3 seconds at 100 Hz. The compressive strengths of the four groups were statistically compared. The resin groups that were lased for 3 seconds at 100 Hz showed a 75% reduction in compressive strength. The results of this study demonstrate that dual wavelength pulsed Nd:YAG laser energy, when used within the parameters described here, will degrade the mechanical properties of composite resin, thereby offering the potential for a quick and efficient method of removing residual composite resin.

UV-B radiometry and dosimetry for solar measurements.

Biologically effective irradiance or dose of solar UV radiation was determined using a spectroradiometer, two broadband radiometers and two types of passive UV-dosimeters. The absolute erythema irradiance and the actinic irradiance were calculated from the solar spectrum measured with the spectroradiometer. It was demonstrated that the erythema irradiance is proportional to the actinic irradiance of solar radiation. The erythema irradiance was also determined using the two broadband radiometers which utilize a filter transmitting erythema spectra. Personal UV-dosimeters such as polysulphone and CR-39 were used to determine the erythema dose for a selected period of time. These results were used to estimate the accuracy of the broadband radiometers and UV-dosimeters. It was found that the results obtained from the broadband radiometers deviate from the absolute erythema irradiance by less than 20% during clear days between the hours of 11:00 and 13:00 Eastern Standard Time (EST) in Australia. The assessment of the erythema dose using passive dosimeters such as polysulphone and CR-39 could introduce an error as high as 40% if the calibration was not performed before undertaking experimental measurements.

Computer image analysis of pigmented skin lesions.

To assist in the distinction of melanoma from benign pigmented lesions, an imaging system was developed, comprising a frame grabber, a microcomputer, a colour video camera and flash lighting with red, green and infrared filters. Over an 18-month period, video images of 70 unselected pigmented lesions for which complete diagnostic data were available, were successfully captured using the camera. Analysis software extracted features relevant to the size, colour, shape and boundary of each lesion, and these features were correlated with clinical and histological characteristics on which standard diagnoses of skin tumours are based. For discriminant analysis based on image analysis measurements, equal probabilities were assigned to three specified diagnostic groups, namely melanoma, naevi and 'other', and four of five melanomas were correctly classified when infrared data were included. However when infrared measurements were omitted, all five melanomas were correctly classified, and the overall accuracy of classification of pigmented lesions was 71%. This system holds promise as an aid in the clinical distinction of melanoma from benign pigmented skin lesions.

The Masters Degree in Medical Physics at Queensland University of Technology--14 years on.

In 1975, the Masters Degree in Medical Physics was first made available at the Queensland Institute of Technology (now Queensland University of Technology, QUT), and is offered on both a part time and full time basis. An option for a Graduate Diploma award after completion of the in-house course work stage is available. The research project may be undertaken either in Brisbane or elsewhere. Such projects have been undertaken in Perth, Hong Kong, Sydney, etc. It is a broad based program, embracing activities of current professional importance while including aspects which have potential importance. Recognition that medical physics is a dynamic speciality ensures that the content of the program is kept under continuous review, and changes made as required. It is of interest to observe that of graduates from the course, approximately 50% have moved into the hospitals and private medical research, 11% into government health departments, 16% into the mining industry, 9% into tertiary education, and 14% into non medical or sales areas. Many have gained senior positions in their selected vocations. The success of the program in providing a useful professional person is due in no small measure to the collaboration of many dedicated professionals in the field. This collaboration relates to informal and formal contact between academic staff and students within the Physics Department, and personnel in hospitals, public health establishments and industry.

Chronic lead nephropathy in Queensland: alternative methods of diagnosis.

Indices of past lead absorption were measured and compared in patients with chronic renal failure from many causes, including some with chronic lead nephropathy. X-ray fluorescence (XRF) yielded finger bone lead concentrations by a new in vivo method. These correlated significantly with excess urinary lead following calcium di-sodium EDTA (ethylenediamine tetra-acetate) and erythrocyte lead concentration. Discriminant function analysis demonstrated that the patients in the study could be separated into two groups without any reference to the EDTA lead excretion test using the following variables, all of which contributed significantly to the discrimination. In order of importance, these were: a childhood history of acute lead poisoning, a history of gout, a family history of gout and detectable XRF finger bone lead. Although the XRF finger bone lead measurement is convenient and non-invasive, its lack of sensitivity (48%) limits its usefulness as a screening test for chronic lead nephropathy.

Chronic renal failure with gout: a marker of chronic lead poisoning.

EDTA (calcium disodium edetate) lead mobilization and x-ray fluorescence (XRF) finger bone lead tests were done in 42 patients with chronic renal failure and without persisting lead intoxication. Nineteen of 23 patients with gout and 8 of 19 without gout had positive EDTA lead mobilization tests. Those patients with gout excreted significantly more excess lead chelate than those without gout. In the gout group 17 patients denied any childhood or industrial exposure to lead. They had a greater number of positive tests and excreted significantly more excess lead chelate than 14 patients with neither gout nor lead exposure. These results confirm that gout in the presence of chronic renal failure is a useful marker of chronic lead poisoning. Of 27 patients with positive lead mobilization tests, only 13 had elevated XRF finger bone lead concentrations (sensitivity 48%). Three of 15 patients with negative lead mobilization tests had elevated XRF finger bone lead concentrations (specificity 80%). Although the XRF finger bone lead test is a convenient noninvasive addition to the diagnostic evaluation of patients with chronic renal failure and gout, its application is limited due to the lack of sensitivity of the method.

In vivo X-ray fluorescence estimation of bone lead concentrations in Queensland adults.

A group of 200 Queensland adults without known health problems had in-vivo estimation of finger bone lead concentrations using X-ray fluorescence analysis (XRF). Forty of these subjects had elevated levels of bone lead of 25 ppm or more, consistent with exposure to the metal. Although the correlation between Queensland residence during childhood and raised bone lead levels was not significant, there were significant correlations between childhood residence in a painted wooden house and raised levels, and between occupational exposure and raised levels. Of the 40 subjects with elevated lead levels only two had neither a history of occupational exposure or childhood residence in a wooden house, whereas 11 of the 25 who had a history of both occupational and residential exposure were positive. The data are consistent with lead in housepaint, or absorbed during occupational exposure, being the two major sources of raised bone lead concentrations.

Liver cadmium concentrations in metal industry workers.

In vivo neutron activation analysis of liver cadmium concentration was performed in 285 metal workers, 130 of whom had been exposed to cadmium in the workplace. Only two workers showed pathological levels in excess of 50 ppm. However, mean liver, urine and blood cadmium levels were significantly different as between the exposed and the unexposed workers. In vivo neutron activation analysis of liver cadmium concentration is easy to perform and can readily be used for industrial screening whenever a hazard is suspected.

Cerebellar calcification--ultrastructure and histochemistry.

The histochemistry and ultrastructure of calcified cerebellar deposits described by Tonge et al. (1977) are reported. The deposits were located by electron microscopy in the walls of blood vessels outside the basement membrane and, in most lesions, consisted of short fibrillar material arranged in multiple lamellae. A number of nonlaminated small bodies were present also. The material coated the vessel walls discontinuously with major and minor protrusions into adjacent nervous tissue. Histochemical analysis detected the presence of sialopolysaccharides in the lesions in adults and in a case of plumbism in a child, with minor differences in the type of sialic acid. X-ray fluorescence analysis supported by histochemical data indicated that, initially, the calcium was bound to the sialic acid and that calcium phosphate appeared in the lesions at a later date. The authors conclude that the lesion is formed by elaboration of sialopolysaccharides at the site but the possibility was not excluded that the polysaccharide may have been derived from a transudate across the vessel wall.

Isolation of Neisseria meningitidis from the urethra, cervix, and anal canal: further observations.

Neisseria meningitidis was recovered from the urethra of nine and from the anal canal of seven men, and from the cervix of two women. Twelve of the 16 men were admitted homosexuals. Seven men had no symptoms, while the remainder had mild to moderate symptoms. One woman was asymptomatic and the other was in hospital with acute salpingitis. Reports of previous isolations of meningococci from the urethra, cervix, or anal canal are reviewed. It is concluded that in men, these infections are usually mild and self-limited, but in women, meningococcal genital infections frequently proceed to severe disease.

Organochlorine pesticide residies in human milk, Western Australia--1970-71.

Milk samples from 22 nursing mothers in the metropolitan area of Perth, Western Australia, have shown the presence of DDT, DDE, dieldrin, and HCB in amounts consistent with similar surveys in other countries. Although mean values tend to be slightly lower than expected, their wide range, 0.002-0.025 ppm for DDT, suggests that a much larger sample should be examined to obtain a more accurate mean. This view is supported by values obtained in another survey of the same area.