In-situ hybridization localized MUC7 mucin gene expression to the mucous acinar cells of human and MUC7-transgenic mouse salivary glands

MUC7 gene that encodes the low molecular weight human salivary mucin MG2, was previously shown to be expressed in tissue-specific manner in normal human salivary glands and in salivary glands of transgenic mice carrying the MUC7 transgene. The purpose of this study was to examine the cell specificity of MUC7 expression in human and transgenic mice salivary glands. To localize the MUC7 transcripts, we used in-situ hybridization in combination with Tyramide Signal Amplification procedure. The results clearly showed that in both the human and transgenic mice salivary gland tissue sections, MUC7 transcripts were localized only in mucous acinar cells; no signals were found in serous acinar cells or any other cell types present in these salivary glands.

Inhibition of esterases in the marine gastropod Littorina littorea exposed to cadmium

Electrophoretic analysis of Littorina littorea esterases indicated the presence of a cathodal migration isoenzyme (EST-C), which was identified in extracts obtained from the gonad-digestive gland complex. A loss of EST-C enzyme activity was observed in individuals exposed to Cd2+. This loss of activity was complete in 86% of individuals dead by the action of Cd2+ and in 68% of those individuals that survived Cd2+ exposure. This difference was statistically significant. In vitro inhibition of esterases by different concentrations of Cd2+ and Cu2+ was studied in individuals not experimentally exposed to heavy metals, to determine whether EST-C inhibition was caused by direct binding of Cd2+ to the esterase molecule or by Cd2+ displacement of a metal ion from essential Cu2+- or Zn2+-containing proteins, which may then be responsible for the inhibition of esterase. Contrary to what happened when individuals were exposed to Cd2+, in the in vitro experiment with Cd2+, inhibition of anodal but not cathodal systems was observed. At the same time, when Cu2+ was used in the in vitro experiment, both anodal and cathodal systems were inhibited. These results suggest that the inhibition of EST-C activity by Cd2+ takes place in vivo and seems not to be due to the direct action of Cd2+ on the molecule, but rather is a process in which transcriptional, posttranscriptional, and other inhibitory processes may be involved.

[Use of a personal computer in the epidemiologic intervention on acute respiratory infections]

A discussion is carried out on the use of a general-purpose personal computer as an aid for taking prophylactic and control steps in the face of epidemics due to acute respiratory infections.

Solar urticaria enhanced through clothing

Solar urticaria is characterized by itching, erythema and wheeling immediately after exposure to radiation in the ultraviolet (UVB, UVA) and visible spectra. Although its exact mechanism remains unknown, evidence supports an immunologic pathogenesis. We describe an unusual patient with solar urticaria who had more severe involvement in skin irradiated with UVA light through white clothing. We propose that optical whiteners in clothing and detergents had absorbed UVA radiation, transforming it into visible light, which was responsible for the urticarial response.

[Nontuberculous mycobacteria in patients with cystic fibrosis]

The prevalence of nontuberculous mycobacteria (NTM) isolated from the lower airways of adult cystic fibrosis (CF) patients appears to be increasing. Different centers of USA, England, Sweden and Ireland have reported a prevalence ranging from 1.5 to 19.5%. The aim of the present study was to investigate the presence of NTM in patients assisted at these centers. A total of 92 sputum specimens and/or gastric contents from 40 CF patients were studied. Ages of patients ranged from 4 months to 25 years. Samples were obtained during acute exacerbation or in routine check-up. Mycobacterium avium-intracellulare complex strains were isolated from six patients with moderate or severe clinical manifestations. Five of these patients were considered as being colonized by NTM. Active mycobacterial disease was diagnosed in one patient and he underwent treatment. The index of bacterial contamination of cultures was very high early along the study (57%), decreasing to 2.8% later due to a change in the methodology used in the processing of samples. It was concluded that the presence of NTM is relatively frequent in patients with CF, even in children with moderate or severe compromise, a fact which strongly suggests that NTM should be systematically searched for considering the possibility that the patients might develop active disease.

Expression of human erythropoietin transgenes and of the endogenous WAP gene in the mammary gland of transgenic rabbits during gestation and lactation

An understanding of the expression of transgenes in the mammary gland during gestation and lactation is crucial for the use of transgenic mammals as bioreactors. Here we describe the temporal pattern of expression of the endogenous rabbit WAP gene and human erythropoietin (hEPO) transgenes under the control of rabbit WAP promoter and 3' flanking sequences. The endogenous rabbit WAP gene was expressed throughout gestation including the day of mating, as well as during lactation in transgenic rabbits bearing a minigene construct. In non-pregnant cycling females, WAP expression was found independent of transgenic status; however, WAP expression was not detected in non-cycling females. The significance of this new finding is not clear at present. hEPO mRNA was detected in mammary gland biopsies from pregnant transgenic rabbits only on day 28 of gestation. During lactation, transcripts were present in mammary gland biopsy samples taken on days 0, 7, 14 and 21. A sharp decline in the levels of transcripts was found for an hEPOcDNA gene construct at the end of lactation (day 28). Although the levels of hEPO were too low to allow a conclusion to be drawn regarding temporal or position-dependent expression, this finding may reflect an integration position effect.

Seasonal variation in maxillary antral pseudocysts in a general clinic population

OBJECTIVES

To determine overall prevalence of maxillary antral pseudocysts and the effect of seasonal variation, allergies, asthma and current smoking status.

METHODS

Panoramic radiographs of 1175 dental clinic outpatients were examined. Data on the prevalence of allergies, asthma and smoking status was obtained from the medical records and age- and gender-matched controls. chi-square tests were used to determine the relationship between these factors and seasonal variation in prevalence.

RESULTS

Pseudocysts were found in 114 (9.7%) patients. Eleven patients (9.7%) reported a history of environmental allergies, nine (7.9%) were asthmatic and 21 (19.6%) current cigarette smokers. Compared with controls, the association between each of these findings and the presence of pseudocysts was not significant. 44.3% of the pseudocysts were detected in November, December and January compared with only 8.6% in April, May and June: this variation was significant (alpha = 0.01).

CONCLUSIONS

The marked increase in the prevalence of pseudocysts during cold winter months supports the concept that seasonal variation may be related to an increased incidence in viremias or irritation from dry forced air heating during this period.

Use of panoramic radiography among an ambulatory dental population to detect patients at risk of stroke

Panoramic radiographs of 3.6 percent of 1,175 newly accepted dental school patients displayed calcifications in the area of the carotid vasculature. The authors interviewed the patients with calcifications to determine whether they exhibited any recognized atherosclerosis, risk factors. One patient had symptoms of atherosclerosis, and a statistically significant correlation was found for obesity among the patients interviewed. The authors concluded that panoramic radiography is useful for identifying some asymptomatic patients with carotid calcifications. These patients should be referred to their physicians promptly for a cerebrovascular work-up as part of an active stroke-prevention strategy.

Disruption of sleep recovery after 36 hours of exposure to moderately bright light

Eight young adults were exposed to either 36 hours of moderate bright light (BL; 1,000-2,000 lux) or a light/dark cycle (L/D < 50 lux) during constant routine. Sleep was recorded on the two subsequent recovery sleeps (R1 and R2) and compared to baseline. After the BL exposure, the rebound of stage 4 sleep and slow wave activity (SWA) were split over R1 and R2, whereas after the L/D cycle, the stage 4 sleep debt was almost completely compensated for during R1. During R1, stage 2 sleep and wakefulness accumulated faster in the BL condition than in the L/D condition. An elevation of the temperature level was also found during R1 of the BL condition. No differences between light conditions were found in urinary levels of melatonin or cortisol secreted during R1 or R2. Homeostasic process does not appear to be affected by the BL condition. A modification in the sleep-wake balance and a change in the temporal relationship between the circadian system and the sleep-wake cycle are discussed.

Risk factors for infection with malaria in a low endemic community in Bataan, the Philippines

The patterns of malaria morbidity and mortality can vary with the level of malaria transmission in a given area. We carried out two annual cross-sectional surveys in the hypoendemic malarious community of Morong, the Philippines, to examine epidemiologic and sociobehavioural risk factors for infection. In both surveys, the greatest risk of having malaria was associated with place of residence. For example, in the first survey, living in an area where more than 50% of the community had a high IFAT titer had an adjusted odds ratio (OR) of 33.7. A range of activities thought to be associated with risk were examined, but in the first survey, only frequent nocturnal visits to the forest were found to be a significant risk factor overall (adjusted OR; 2.65; 95% CI 1.48, 4.73), but this phenomenon was primarily observed among individuals residing in the lowest prevalence areas. In the second survey, where only the area with a relatively high prevalence of malaria was sampled, no association with activities was found. In this survey, significant factors associated with malarial infection were: being a migrant (adjusted OR 1.97; 95% CI 1.33, 2.92), being male (adjusted OR 1.63; 95% CI 1.10, 2.43) and age 30 years or less (adjusted OR 0.29 for age > 30 years; 95% CI 0.16, 0.52). The data suggest that in low-endemic communities like Morong, Bataan, control efforts should be primarily directed to focal areas identified by serology, particularly among migrants and among male young adults.

Localized cellular inflammatory responses to subcutaneously implanted dental mercury

Previous reports have demonstrated mercury accumulation and toxicity in oral tissues following exposure to mercury vapor from dental amalgam restorations. In the present study, inflammatory responses to subcutaneously administered mercury were assessed histopathologically and immunocytochemically in a rat model system. A panel of six well-characterized monoclonal antibodies specific for monocytes, macrophage subsets, T and B lymphocytes, and major histocompatibility complex (MHC) class II (la) determinants was used to quantitate alterations in mononuclear cell subsets in situ at time intervals from 2 d to 8 wk. The results revealed acute inflammatory cell infiltration at 2 and 3 d, followed by chronic inflammation that persisted after 8 wk. The numbers of monocytes, resident macrophage subsets, and mononuclear cells expressing la antigen were significantly different from control tissues at 1-2 wk. The numbers of resident macrophages remained significantly higher even after 8 wk. These data showed that in situ mercury accumulation can lead to altered expression of MHC class II determinants with persistent chronic inflammation and shifts in mononuclear cell subpopulations.

The effect on body temperature and melatonin of a 39-h constant routine with two different light levels at nighttime

Eight healthy subjects were studied during 39-h spans (from 07:00 on one day until 22:00 the second) in which they remained awake. During one experiment, subjects were exposed to 100 lux of light between 18:00 and 8:00, and during a second experiment, they were exposed to 1000 lux during the same time span. Throughout the daytime period, they were exposed to normal daylight (1500 lux or more). The nighttime 1000-lux light treatment suppressed the melatonin metabolite aMT6s, while the 100 lux treatment did not. On the treatment day, the 1000 lux, in comparison to the 100 lux, light treatment resulted in both an elevated temperature minimum and a delay in its clock-time occurrence overnight. No real circadian phase shift in the temperature, urinary melatonin, or cortisol rhythms was detected after light treatment. This study confirmed that nocturnal exposure to lower light intensities is capable of modifying circadian variables more than previously estimated. The immediate effects of all-night light treatment are essentially not different from those of evening light. This may be important if bright light is used to improve alertness of night workers. Whether subsequent daytime alertness and sleep recovery are affected by the protocol used in our study remains to be determined.