An exploratory qualitative study examining the social and psychological processes involved in regular dental attendance

OBJECTIVE

This study aimed to provide a description of the psychosocial process involved in regular dental attendance.

METHODS

The study design was a qualitative cross-sectional study using unstructured and semistructured interviews and observations of regular dental visits. The study participants included 12 men and 18 women attending general dental practices and six men and four women attending an emergency dental service. The data were systematically recorded and subjected to line-by-line grounded theory coding around the main concerns of those attending the dentist.

RESULTS

The main concern of those attending for a regular dental visit was checking their oral health. The six-month recall was conceptualized as a checking cycle in six phases: recalling, responding, inducing (i), waiting, inducing (ii), and telling. The possible outcomes of the cycle were maintaining oral health, sustaining oral health, and a further checking cycle. Variations in checking cycles resulted from reordering and normalizing pressures within participants' lifestyles.

CONCLUSIONS

The findings of this study suggest that people's patterns of dental attendance are similar to those of other chronic illnesses. An understanding of the dynamic psychosocial processes involved in frequent dental attendance may be achieved when further research into this phenomenon is conducted.

A model-independent maximum-entropy method for the inversion of small-angle X-ray diffraction patterns

A model-independent maximum-entropy method is presented which will produce a structural model from small-angle X-ray diffraction data of disordered systems using no other prior information. In this respect, it differs from conventional maximum-entropy methods which assume the form of scattering entitiesa priori. The method is demonstrated using a number of different simulated diffraction patterns, and applied to real data obtained from perfluorinated ionomer membranes, in particular Nafion™, and a liquid crystalline copolymer of 1,4-oxybenzoate and 2,6-oxynaphthoate (B–N).

Visualization of oxygen radical production in mouse liver in response to infection with Schistosoma mansoni

BACKGROUND/AIMS

The tropical parasite S. mansoni induces granulomatous inflammation in the liver, following the lodging of eggs in this organ. In vitro studies suggested that the host's response might involve the production of oxygen radicals.

METHODS

In an attempt to investigate the situation at the site of inflammation, under disease conditions, livers of infected mice were treated with dichlorodihydrofluorescein diacetate which fluoresces after oxidation.

RESULTS

Fluorescence of the oxidized tracer revealed that oxygen radicals were produced by granulomatous inflammatory cells. The phenomenon reached its highest intensity close to the eggs. The membranes of the cells were strongly labelled, probably reflecting membrane-associated NADPH oxidase activity. The cytoplasm of hepatocytes was also fluorescent but with lower intensity; hepatocyte membranes or nuclei were not labelled. Fluorescence was reduced drastically by treatment with catalase and antioxidants, indicating the occurrence of H2O2. Treatment with superoxide dismutase had no effect. Neither the livers of uninfected animals nor those of infected animals before parasite egg deposition were labelled. Eosinophil peroxidase activity was released in the areas of inflammatory cells, but was not found in hepatocytes.

CONCLUSIONS

The H2O2/peroxidase system, which is the cornerstone of the antimicrobial defense associated with inflammation, is activated in close contact with parasite eggs. The process does contribute to egg killing in vivo. Moreover, hepatocytes undergo oxidative stress in the entire organ. This finding is in agreement with the parasite-induced decrease of liver antioxidant defenses demonstrated previously.

Infection of mice by a Toxoplasma gondii isolate from an AIDS patient: virulence and activation of hosts' immune responses are independent of parasite genotype

Virulence of a Toxoplasma gondii isolate from an AIDS patient (designated as PTN) was compared with that of PLK, a variant of P-strain. Virulence was assessed in term of host survival upon inoculation in different strains of mice. All C57BL/6 mice died of acute toxoplasmosis by 7-10 days following intraperitoneal infection with 1 x 105 tachyzoites of PTN and 40% of BALB/c died on day 23 of infection, whereas 100% CBA/J infected with the same dose of PTN survived, as did outbred Swiss Webster mice. All C57BL/6, BALB/c, CBA/J, or Swiss Webster died of acute toxoplasmosis by 3-9 days postinfection upon inoculation with same dose of tachyzoites of the PLK strain. Further studies in CBA/J mice demonstrated that mice infected with PTN elicited a significantly higher lymphoproliferative response to crosslinked anti-CD3 mAb or Con A than PLK infected mice, and augmented production of TNFalpha, lower levels of nitrite and a higher number of NK cells. Genetical analysis indicated that both PLK and PTN strains of T. gondii are from type ll. Interestingly, being of the same genotype, the later showed less virulence upon inoculation in mice and had greater capacity to activate host immune system than the PLK strain.

Principles for Sustainable Governance of the Oceans

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.

Failed or difficult laparoscopic cholecystectomy: can preoperative ultrasonography identify potential problems?

A prospective study was performed to assess the role of preoperative ultrasonography in predicting failed or difficult laparoscopic cholecystectomy. Fifty patients underwent detailed preoperative ultrasound examinations. The number and size of calculi, evidence of acute or chronic cholecystitis, gallbladder morphology, and the presence or absence of aberrant anatomy were documented. A comparison was made of the surgical outcome and the ultrasound findings in each patient. Six patients were converted to open cholecystectomy because of inflammatory changes in the gallbladder. The preoperative ultrasound studies in 5 of these patients demonstrated evidence of cholecystitis and cholelithiasis. Gallbladder wall thickening and contraction were also seen. Five gallbladder resections had intraoperative difficulties; preoperative ultrasonography demonstrated a thickened gallbladder wall in 2. Of 31 uneventful cases, 7 had evidence of gallbladder wall thickening and/or contraction. There were no ultrasound features that identified between the unsuccessful, difficult, or uneventful laparoscopic cholecystectomies. We conclude that detailed preoperative ultrasound evaluation of the gallbladder in patients destined for laparoscopic cholecystectomy is of little value in screening for difficult or unsuitable cases.

Evidence of mobilization of hobo transposons in a P-element mutagenesis screen

In Drosophila melanogaster, mutations in Su(var) and En(var) loci either suppress or enhance position effect variegation, respectively. Towards the cloning of these genes we have induced, recovered, and characterized a series of Su(var) mutations located on the third chromosome. These mutations were recovered from a P-element mutagenesis scheme in which the third chromosome P[ry+ delta 2-3](99B) element would provide transposase in trans to mobilize a single nonautonomous P transposon, P[pUCHSNeo](9C), located on the X chromosome. Although this cross scheme induces mobilization of the X-chromosome P transposons and its subsequent reinsertion onto the autosomes, none of the Su(var) mutations recovered could be associated with P-transposon insertions. Further investigation of these mutations by in situ hybridization showed that another mobile element that can be mobilized in hybrids, hobo, was associated with these mutations. We conclude that the mobilization and reinsertion of the hobo elements, through an inadvertent hybrid HE dysgenic cross, is most likely responsible for the Su(var) mutations recovered from this P-element mutagenesis. The association of hobo element with this Su(var) locus will facilitate its cloning and offers the possibility of hobo transposon tagging other Su(var) loci.

The use of the major anoxic stress response protein P34, the K isozyme of lactate dehydrogenase, and carcinoembryonic antigen in the follow-up of patients with colorectal adenocarcinoma

BACKGROUND

This prospective study evaluated the use of the K isozyme of lactate dehydrogenase (LDH-K) as a complementary tumor marker to carcinoembryonic antigen (CEA) in patients with colorectal adenocarcinoma.

METHODS

In this series, 355 patients underwent potentially curative surgery for primary colorectal adenocarcinoma. A close surveillance program of follow-up revealed 108 patients (30%) who had a serum elevation in CEA and/or LDH-K.

RESULTS

The patients were divided into three groups. Group 1 consisted of 43 patients with elevations in CEA alone. Twenty-seven of 43 patients (63%) had tumor at exploratory laparotomy; and 16 patients (37%) had no evidence of disease after a median follow-up of 74 months. Group 2 consisted of 33 patients with a serum elevation of LDH-K alone. In this group, 5 of 33 patients (15%) had recurrent disease with true elevations of LDH-K. In 28 patients (85%), there were falsely elevated levels of LDH-K with no evidence of disease. Group 3 consisted of 32 patients with elevations of both serum LDH-K and CEA. In this group, 17 of 32 patients (53%) had true elevations of CEA and LDH-K with tumor recurrence, and 15 patients (47%) had false elevations with no evidence of disease.

CONCLUSION

LDH-K did not complement CEA as a tumor marker for detecting recurrence in this group of patients with colorectal cancer.

Differential inhibition of dopamine and bromocriptine on induced prolactin release: multiple sites for the inhibition of dopamine

Effects of dopamine and bromocriptine on TRH- or dibutyryladenosine 3',5'-cyclic monophosphate (dbcAMP)-induced prolactin release from primary cultured rat pituitary cells were studied using a perifusion system. TRH (100 nmol/l) stimulated prolactin release from basal concentrations of 33.8 +/- 0.5 to 151.2 +/- 28.0 ng/ml (net increase) or 447% increase. Dopamine inhibited the basal release of prolactin throughout the experiment, but TRH (100 nmol/l) was still able to stimulate prolactin release under the influence of dopamine. The increment in prolactin release was inversely proportional to the dopamine concentration. When TRH (100 nmol/l) was introduced during a perifusion period with bromocriptine 1 nmol/l, the prolactin concentration was increased to 110.9% of basal levels. The stimulatory effect of TRH under the influence of bromocriptine (1 nmol/l) was significantly lower than that without bromocriptine (control), although the higher concentrations of bromocriptine (10 and 100 nmol/l) did not further reduce the peak concentration of TRH-induced prolactin release. During a perifusion period with a low concentration of dopamine (1 nmol/l plus 0.1 mmol/l ascorbic acid), introduction of dbcAMP (3 mmol/l) stimulated prolactin release to 48% of basal concentration. A higher concentration of dopamine further reduced the stimulatory effect of prolactin release. Bromocriptine impeded the stimulatory effect of dbcAMP (3 mmol/l) on prolactin release in a similar manner as dopamine. Since a higher concentration of bromocriptine (10 and 100 nmol/l) did not further inhibit the TRH-induced prolactin release whereas a higher concentration of dopamine did, it is concluded that dopamine acts through additional mechanism(s) other than the D2 receptor transduction system.

Gd-DOTA-enhanced MR imaging and color Doppler US of renal allograft necrosis

In 21 recipients of renal transplants suspected of allograft necrosis, the authors correlated the results of imaging to pathologic and histologic data in order to describe the magnetic resonance (MR) imaging and color Doppler ultrasonographic (US) characteristics of infarction. All patients underwent MR imaging performed with and without gadolinium tetraazacyclododecanetetraacetic acid (DOTA) and color Doppler US. Nonenhanced T1-weighted images showed no obvious changes, whereas nonenhanced T2-weighted images demonstrated a slight increase in signal intensity in areas of ischemic necrosis and low or heterogeneous signal intensity in areas of hemorrhagic necrosis. Gd-DOTA-enhanced MR images showed no contrast material uptake in infarcted areas. Color Doppler US characteristics of infarction included absence of Doppler signal and alteration of the cortical echogenic structure, particularly in cases of ischemic necrosis. Color Doppler US allows measurement of vascular resistance and assessment of intrarenal vasculature and the renal pedicle. Gd-DOTA-enhanced MR imaging is useful in confirming the diagnosis of infarction and provides an accurate evaluation of the extent of the infarct.

Primary de novo adenocarcinoma of the colon measuring 8 mm in diameter with lymph node metastases. Report of a case

Colonic adenocarcinomas measuring less than 10 mm are rare. Herein, we report a carcinoma measuring 8 mm in diameter associated with subserosal extension through a "locus minoris resistentiae" and metastases to lymph nodes, an association not previously reported. No residual adenomatous tissue was found, suggesting a de novo carcinoma.

MR imaging of renal transplant rejection

The results of 62 consecutive MR examinations were correlated with the subsequent clinical course and histologic results. Twenty-six cases of rejection showed a marked diminution of cortico-medullary differentiation (CMD). The renal parenchymal vascular pattern and visibility of renal sinus fat were not markedly altered in rejection and there was no difference between normal and rejected allograft shape. The ability of MR imaging to diagnose renal transplant rejection is only based on CMD, which, however, is non-specific. In 2 cases of severe acute rejection, T2 weighted images showed an abnormal signal intensity of the cortex due to renal infarction. Our preliminary results in 8 patients with Gd-DOTA injection showed 2 cases with necrosis seen as areas with absent contrast enhancement. This technique seems to be promising in the detection of perfusion defects.