Medication-related osteonecrosis of the jaw. Implant presence-triggered osteonecrosis: Case series and literature review

PURPOSE

The aim of this study was to review the characteristics of 'implant presence-triggered osteonecrosis' (IPTO) in the literature and identify possible differences between IPTOs and 'implant surgery-triggered osteonecrosis' (ISTO).

MATERIALS AND METHODS

Reviews using PubMed and the Cochrane Database of Systematic Reviews were performed from 2009-2018; the focus was on medication-related osteonecrosis of the jaw (MRONJ) and dental implants. In addition, the hospital records of all patients presented in our department with IPTO were retrospectively reviewed. In both studies, the following data were collected: the number of patients with ISTO or IPTO, age, gender, location, stage of MRONJ, number of implants involved in MRONJ, the elapsed time between the placement of the implants and the development of MRONJ, applied treatment and the presence of mandibular fractures and progress.

RESULTS

The literature review provided 111 articles. Nine of the articles were selected for bibliographic review. The number of osteonecrosis cases was significantly higher in the IPTO group (74 cases) compared with the ISTO group (27 cases). The duration of the anti-resorptive treatment (oral and intravenous) was also longer in the IPTO group. In our centre, seven patients with IPTO were chosen; however, no patients with ISTO were selected. The significant differences between the patients in our series and the information collected in the literature for the IPTO group were the time of ingestion of alendronate, the elapsed time from the placement of the implants to the development of the MRONJ and the number of implants linked to the development of a complication.

CONCLUSIONS

The use of antiresorptives causes osteonecrosis in patients with implants that are subjected to functional loading, and this occurs at a higher frequency than what is observed after implant placement surgery.

Nanomolar ouabain elicits apoptosis through a direct action on HeLa cell mitochondria

The steroid Na(+)/K(+) ATPase (NKA) blocker ouabain has been shown to exhibit pro-apoptotic effects in various cell systems; however, the mechanism involved in those effects is unclear. Here, we have demonstrated that incubation of HeLa cells during 24h with nanomolar concentrations of ouabain or digoxin causes apoptotic death of 30-50% of the cells. Ouabain caused the activation of caspases-3/7 and -9; however, caspase-8 was unaffected. The fact that compound Z-LEHD-FMK reduced both apoptosis and caspase-9 activation elicited by ouabain, suggest a mitochondrially-mediated pathway. This was strengthened by the fact that ouabain caused ATP depletion and the release of mitochondrial cytochrome c into the cytosol. Furthermore, upon ouabain treatment mitochondrial disruption and redistribution into the cytosol were observed. A mitochondrial site of action for ouabain was further corroborated by tight co-localisation of fluorescent ouabain with mitochondria. Finally, in ouabain-treated cells the histamine-elicited elevation of cytosolic Ca(2+) concentration ([Ca(2+)]c) suggests an additional effect on the endoplasmic reticulum (ER) leading to Ca(2+) store depletion. We conclude that fluorescent ouabain is taken up and tightly co-localises with mitochondria of HeLa cells. This indicates that apoptosis may be triggered by a direct action of ouabain on mitochondria.

Ouabain enhances exocytosis through the regulation of calcium handling by the endoplasmic reticulum of chromaffin cells

The augmentation of neurotransmitter and hormone release produced by ouabain inhibition of plasmalemmal Na+/K+-ATPase (NKA) is well established. However, the mechanism underlying this action is still controversial. Here we have shown that in bovine adrenal chromaffin cells ouabain diminished the mobility of chromaffin vesicles, an indication of greater number of docked vesicles at subplasmalemmal exocytotic sites. On the other hand, ouabain augmented the number of vesicles undergoing exocytosis in response to a K+ pulse, rather than the quantal size of single vesicles. Furthermore, ouabain produced a tiny and slow Ca2+ release from the endoplasmic reticulum (ER) and gradually augmented the transient elevations of the cytosolic Ca2+ concentrations ([Ca2+]c) triggered by K+ pulses. These effects were paralleled by gradual increments of the transient catecholamine release responses triggered by sequential K+ pulses applied to chromaffin cell populations treated with ouabain. Both, the increases of K+-elicited [Ca2+]c and secretion in ouabain-treated cells were blocked by thapsigargin (THAPSI), 2-aminoethoxydiphenyl borate (2-APB) and caffeine. These results are compatible with the view that ouabain may enhance the ER Ca2+ load and facilitate the Ca2+-induced-Ca2+ release (CICR) component of the [Ca2+]c signal generated during K+ depolarisation. This could explain the potentiating effects of ouabain on exocytosis.

Real time measurement of stimulated dopamine release in the conscious rat using fast cyclic voltammetry: dopamine release is not observed during intracranial self stimulation

Fast cyclic voltammetry (FCV) was used to measure real time release of electrically stimulated endogenous dopamine in the nucleus accumbens (NAc) of conscious freely moving rats for up to 17 days. The method of electrode construction, implantation, electrical stimulation and recording of changes of extracellular dopamine concentration in the conscious rat are described. Rats trained on a continuous reinforcement schedule to perform intracranial self stimulation (ICSS) were implanted with electrodes for FCV. During ICSS, no faradaic signal was observed at an electrode implanted in the NAc. Decreasing the intensity of the stimulating current abolished ICSS, increasing the stimulating current disrupted ICSS. Operator delivered electrical stimulations using currents greater than those needed for ICSS yielded dopamine signals. It is concluded that during ICSS, sufficient dopamine does not reach the extracellular fluid space to yield a faradaic signal detectable by FCV.

[The demand for emergency medical care by the prison population]

BACKGROUND

Urgent medical claim from recluse population shows some special traits due to firstly, the reclusion situation itself and the high prevalence of certain diseases in this population, as the infections ones, such as HIV infection, hepatitis B and tuberculosis. Moreover, emergency rooms constitute for this patients, a common previous admission place. Thus, a high and a complex medical care claim must be expected from this population in hospital emergency rooms.

METHODS

Consultations from ill prisoners examined in emergency room of Hospital Clinic Internal Medicine department during 1993, were checked: Age, sex, date, time of visit, serology and HIV risk factor, stage infection among positive HIV subjects, cause of complaint. age o symptomatology, number and the kind of complementary examinations done, the consulting time, the diagnosis and its link to the HIV infections, the consulting recurrence, and its relation with the initial cause, and the patient final destiny.

RESULTS

394 patients, from 598 who consulted, were visited (1.8% total consultings). The mean age was 32.4 years and 92% were men. A 68% (268 patients) realized that had HIV infection, and among these, a 37% (99 patients) were AIDS. The most frequent cause of complaint were related to respiratory, digestive, neurologic and non foci fever, which caused the higher number of admissions. The tuberculosis diagnosis was done in 39 patients (9.9%). Sixty wine patients discharged from hospital on first examination came again one or more times to the emergency room because of the same complaint. The number of complementary examinations done was 1,370 (a mean of 2.4 per visit), and were significantly higher among the HIV patients than in negative or unknown (p < 0.001). The overall admissions average was 37%, which increased to 71% among patients visited repeatedly. The HIV recluse patients required admission in the 46.3% of visits, and the HIV negative ones, in the 20.6% (p < 0.001). The duration of the visit among the patients that were discharged was 4 hours and 54 minutes.

CONCLUSION

Recluse population generates an important urgent medical care claim. The number of admissions among this population is elevated and higher than the respective to the general one, related to the age. This high number of consulting, the increased number of admissions and the complex assistance (high number of complementary examinations that often requires high technology, and the repetitive urgent visits, etc.), are caused, mainly by the high prevalence of HIV infections among this population.

Necrotising colitis with perforation in diarrhoic patients treated with loperamide

Two cases of necrotising enterocolitis with perforation occurred in patients with paralytic ileus after loperamide therapy. The possible role of loperamide in the pathogenesis of the complications is suggested.