Sequential 3D X-ray microtomographic measurement of enamel and dentine ablation by an Er:YAG laser

OBJECTIVE: To demonstrate the progression of crater growth during repeated sequential application of an Er:YAG laser to enamel and dentine, monitored using X-ray microtomography (XMT). DESIGN: A single centre study in which laser craters were created in blocks cut from human enamel and/or dentine under standardised and known conditions and then studied using XMT to obtain visualisation and quantification of the effects. SETTING: University setting, UK, 2001. MAIN OUTCOME MEASURES: Success was judged by an ability to obtain useful 3D XMT reconstructions of the blocks during crater development, and to make measurements from these data. These measurements were compared with data obtained from similar studies using different measurement techniques. RESULTS: Time sequences of 2D and 3D images were obtained which demonstrated the progression of laser craters in enamel and dentine. Quantitative measurements from these data enabled values to be derived for the rate of progression of crater depth per unit energy, and the volume of hard tissue removed per unit energy. These values were compared with data derived from other studies and shown to be broadly comparable. However, the present study is unique in that these values were obtained from a series of measurements of the same craters over time. CONCLUSIONS: 3D X-ray microtomography is shown to be a useful tool for quantitative measurements in dental research. For the Er:YAG laser, the relationship of laser crater depth and volume of mineral removed to applied energy was found to be linear.     

Diverticulitis in the younger patient

BACKGROUND: The purpose of this study was to examine the presentation of diverticulitis at an urban county hospital serving predominantly indigent patients and to analyze the differences, if any, in presentation and treatment in younger patients. METHODS: A retrospective review of medical records from 1995 to 2001 was performed at a single institution to identify patients admitted to the surgical service with the diagnosis of diverticular disease. Inclusion criteria were either diverticulitis confirmed at operation or radiographic findings consistent with the disease. Patient demographics, history, pertinent physical findings, and treatment were recorded. The data were analyzed after dividing the patients into two populations: a younger population 50 years of age or less, and a second population of patients older than 50. RESULTS: During the interval, a total of 64 patients were admitted to the surgical service with the diagnosis of diverticulitis. The mean age of this population was 45.5 years (range 21 to 86). Forty-six patients were under 50 years of age (72%). Analysis of sex differences, type and timing of surgical procedure, and complication rate with respect to age showed no significant difference between the two age groups. CONCLUSIONS: We are clearly treating a younger patient population than previous reports on patients with diverticulitis. Although there was a trend toward increased surgical intervention in the younger population, this number did not reach statistical significance. Diverticulitis in young patients at our institution does not appear to take a more aggressive course than the same disease in older patients.     

Epidemic diphtheria in Ukraine, 1991-1997

In 1991, Ukraine experienced a return of epidemic diphtheria after decades of control that had resulted in <40 sporadic cases reported every year. Increased incidence was first recorded in Kiev, Lviv, and Odessa. By 1993, the epidemic had spread to >50% of the oblasts (provinces) in the country, and by 1995, all regions were affected. In 1995, at the peak of the epidemic, >5,000 cases and >200 deaths were reported. As in Russia, >80% of these cases were diagnosed in persons 16-59 years old. In 1993, the government of Ukraine initiated a program of increased immunization among children and at-risk adults, and by 1995, a mass immunization strategy was adopted in an effort to arrest the epidemic, which was increasing exponentially. In 1996, the number of cases started to decrease, and data from 1998 indicate that the downward trend has continued. It is likely that the diphtheria epidemic in Ukraine started among children, who had been left vulnerable due to inadequate childhood immunizations, and then quickly spread to inadequately protected adults.     

The influence of endogenous dopamine levels on the density of [H]SCH23390-binding sites in the brain of the honey bee, Apis mellifera L

This paper examines the relationship between endogenous dopamine (DA) levels and the density of [³H]SCH23390-binding sites in the brain of the adult worker honey bee. DA levels were reduced pharmacologically using a single 10 μl injection of either α-methyl- -p-tyrosine (AMT; 250 μg or 500 μg) or α-methyl- -tryptophan (AMTP; 250 or 500 μg) into the haemolymph of the bee. In all cases, maximum depletion of DA was observed 3 h after treatment, but in bees treated with AMTP (250 or 500 μg) or with 250 μg AMT, DA levels returned to normal within 24 h of treatment. Neither AMT nor AMTP was selective for DA: both drugs also reduced serotonin (5-hydroxytryptamine, 5HT) levels in the brain. However, AMTP was more effective than AMT at depleting 5HT, whereas for DA, the reverse was true. Depletion of DA levels, using 250 μg AMT, led to a dramatic decline in the levels of specific binding of [³H]SCH23390, defined in this study as binding in the presence of 5×10⁻⁶ M cis-(Z)-flupentixol (see Ref. [28]). In contrast, naturally occurring diel fluctuations in DA levels, identified in the optic lobes of the brain, and changes in brain DA levels resulting from queenlessness, had no significant effect on the density of [³H]SCH23390-binding sites in the brain of the bee. Overall, these results indicate that under normal physiological conditions, there is no direct link in honey bees between changes in endogenous brain DA levels and the density of D₁-like receptors labelled by [³H]SCH23390.     

Long Term Prognosis Following Treatment in a Coronary-Care Unit

Summary: A three-year follow-up of 244 patients admitted to a coronary-care unit is described. The cases were the hospital survivors of 300 patients who had originally been assessed by a coronary prognostic index (CPI) for short-term survival. They were followed firstly, in order to check the findings from an earlier group of patients on whom a second CPI for three years survival had been formulated. Secondly, it had previously been established that acute prognosis was improved by treatment in the coronary-care unit for a group of these patients, and it was therefore important to check their long-term survival. Thirdly, the data provided an opportunity for assessing the effect of arrhythmias during acute myocardial infarction on subsequent survival.
The previous findings were confirmed that age, radiological evidence of cardiomegaly and left ventricular failure, and previous myocardial infarction, are all relevant to three year survival. Late mortality was also higher in hypertensive patients, and in those who had suffered anterior transmural infarction. Mortality was well predicted by the CPI for three year survival, and there was no significant difference in mortality from the earlier study. There was no evidence that any arrhythmia during the acute stage of the illness influenced late mortality independently of the other factors.     

Pigmented lesions of the tongue in heroin addicts—fixed drug eruption

Pigmentation of the tongue is an uncommon finding. We describe a case in which it was due to a fixed drug eruption following the inhalation of heroin pyrolysate and methaqualone vapours.     

The effects of location, experiences with the civil disturbances and religion on death anxiety and manifest anxiety in a sample of Northern Ireland university students.

A total of 315 Northern Ireland university students were compared to 302 Republic of Ireland university students in terms of death anxiety, manifest anxiety, and perception of dangerousness of aspects of their environment and attitudes toward the civil disturbances in Northern Ireland. Also using these variables in the Northern Ireland sample, Protestants were compared to Catholics, those having had experiences with the disturbances were compared to those not having had such experiences, and those living in nominally dangerous areas of Belfast were compared to those living in nominally safer areas of Belfast. Students living in Northern Ireland had higher death anxiety and stronger fears than students living in the Republic. Those having had experiences with the civil violence had higher manifest anxiety and stronger fears than those not having has such experiences. Persons living in safe environments thought the disturbances to be more serious than those living in more dangerous environments, a result which is discussed in terms of the media and cognitive dissonance. Finally, an argument is made that the influence of religious denomination is an overemphasized variable in the understanding of the civil disturbances.