Reconstruction of lateral mandibular defects with dynamic bridging plates

The principle of mandibular reconstruction by dynamic bridging plates in association with a bone graft is based on the double bridge reconstruction method. However, the plate can be used alone. Our aim was to report the long-term results of this treatment for mandibular lateral defects in fragile patients. From 1993 to 1999, 38 consecutive patients had primary reconstructions with bridging plate for lateral mandibular defects. Their mean age was 58.4 years (26-86) and the mean follow-up was 50 months (6-89). Excluding removal of plates for local recurrences, the overall success rate was 78%. Plates were removed after a mean of 20.4 months (1-66). No plates fractured. Dynamic bridging plates allow an immediate and efficient reconstruction with reduced operating time and compare favourably with conventional plates. They can also be used as a stand-by for patients who are to have a delayed free flap reconstruction.     

Epidermoid carcinoma of oral cavity in patients less than twenty

OBJECTIVE: To analyze a review of literature of patients aged less than 20 years with epidermoid carcinoma of oral cavity. PATIENTS AND METHODS: Two sources were used to identify cases. A Medline search was performed as well as a review of our Medlog files where two cases of oral epidermoid carcinoma were identified in patients aged less than 20 years. RESULTS: Sixteen patients treated between 1981 and 2000 were included in this study. The mean age was 15.6 years and the sex ratio was 2.2 male/female. The mean time to diagnosis was 16.4 months. Tumors were staged III or IV in 71.4% of cases. The mean follow-up was 33.2 months. Rate of failure was 50% and one patient experienced local recurrence. At last follow-up, seven patients were alive with one patient living with cancer. All deaths resulted from the original cancer. DISCUSSION: This study illustrates the rarity of epidermoid carcinoma of the oral cavity in patients aged less than 20 years. Owing to the fact that most tumors were classified III or IV, time to diagnosis is probably the most important prognosis factor. Histological examination of all lesions of the oral cavity is required, irrespective of the age of the patient.     

Squamous-cell carcinoma of the tongue: treatment results and prognosis

OBJECTIVE: The aim of the study was to assess the results of curative treatment of patients with squamous cell carcinoma of the tongue and to evaluate survival and predictive factors of recurrence. PATIENTS AND METHODS: A series of 309 patients with squamous cell carcinoma of the tongue treated with curative intent was studied from January 1988 to December 1999. The percentage of oral tongue cancer was 82.2 and the percentage of cancer of base of the tongue was 17.8. Most patients underwent surgical procedure alone or combined with radiotherapy (92%). We performed 252 neck dissections. Bilateral dissections were performed for cancer of the apex linguae, cancer of the base of the tongue, for patients with N2c neck disease and whenever the primary tumor site crossed the median line. Twenty-five patients (8%) were treated with radiation therapy alone. Mean follow-up was 55 months. The functional results were assessed within a minimum of 10 months postoperative follow-up. RESULTS: In 45.2%, there was histological evidence of node invasion with 53.5% of extracapsular node spread in the neck specimens. Extracapsular node spread did not influence survival or recurrences. Occult cervical metastasis in an elective neck dissection in clinically negative necks was found in about 20% of patients with 47% of extracapsular node spread (41% for cancer of mobile tongue and 80% for those of base of the tongue). About 23% of patients with cancer of base of the tongue staged N0 had histological node invasion in controlateral neck nodes. The postoperative mortality rate was 0.9%. The rate of complications was 17%. The cancer recurred in 41.7% of all cases. Twelve percent of all patients had second primary cancers of the upper aerodigestive tract. The overall survival and non-recurrence rates at 2 and 5 years were higher in cancer of oral tongue than in cancer of base of the tongue. Survival rates were better when neck nodes were clinically or histologically negatives and in early-stage carcinomas. Non-recurrence rates were better when nodes were clinically or histologically negatives and when margins of exeresis were not involved. The functional results were better in oral tongue cancer than in base of the tongue cancer. DISCUSSION: Prognosis (survival and non-recurrence rates and functional results) of squamous cell carcinomas of oral tongue was better than prognosis of those of base of tongue. We recommend an aggressive surgical procedure even in patients with neck classed N0 (with reservations for T1 lesions with small depth of invasion): an ipsilateral supraomohyoid neck dissection for cancer of oral tongue and a bilateral supraomohyoid neck dissection for cancer of base of the tongue, cancer of oral tongue which crosses the median line of the oral cavity and cancer of the apex linguae. Postoperative radiotherapy must be performed when margins are positives and/or when nodes are involved with or without extracapsular spread.     

Diurnal biting of malaria mosquitoes in the Central African Republic indicates residual transmission may be “out of control”

Malaria control interventions target nocturnal feeding of the Anopheles vectors indoors to reduce parasite transmission. Mass deployment of insecticidal bed nets and indoor residual spraying with insecticides, however, may induce mosquitoes to blood-feed at places and at times when humans are not protected. These changes can set a ceiling to the efficacy of these control interventions, resulting in residual malaria transmission. Despite its relevance for disease transmission, the daily rhythmicity of Anopheles biting behavior is poorly documented, most investigations focusing on crepuscular hours and nighttime. By performing mosquito collections 48-h around the clock, both indoors and outdoors, and by modeling biting events using circular statistics, we evaluated the full daily rhythmicity of biting in urban Bangui, Central African Republic. While the bulk of biting by Anopheles gambiae, Anopheles coluzzii, Anopheles funestus, and Anopheles pharoensis occurred from sunset to sunrise outdoors, unexpectedly ∼20 to 30% of indoor biting occurred during daytime. As biting events did not fully conform to any family of circular distributions, we fitted mixtures of von Mises distributions and found that observations were consistent with three compartments, corresponding indoors to populations of early-night, late-night, and daytime-biting events. It is not known whether these populations of biting events correspond to spatiotemporal heterogeneities or also to distinct mosquito genotypes/phenotypes belonging consistently to each compartment. Prevalence of Plasmodium falciparum in nighttime- and daytime-biting mosquitoes was the same. As >50% of biting occurs in Bangui when people are unprotected, malaria control interventions outside the domiciliary environment should be envisaged.

Transmission of parasites of the genus Plasmodium that are the causative agents of human malaria is considered to occur mainly from sunset to sunrise, when their vectors, mosquitoes of the genus Anopheles, feed on human hosts that are at rest or asleep (1, 2). This principle is so firmly established that sampling protocols to measure the strength of transmission usually disregard diurnal Anopheles feeding (3). This has not always been so: sampling routines implemented in the early 20th century by medical entomologists generally covered the whole 24-h biting cycle of different mosquito species (4). It is generally assumed that nighttime blood-feeding evolved because hosts are less active at this time, so that mosquitoes incur a lower risk of being swatted or chased away, enabling higher feeding success (2). Human hosts, however, most often rest indoors; many human-biting anophelines, therefore, penetrate inside households in order to have access to and feed on humans. Current mainstay vector control tactics exploit these behaviors in order to reduce transmission by means of two interventions: protecting humans under long-lasting insecticidal bed nets (LLINs), and spraying houses with residual insecticides (i.e., indoor residual spraying, IRS) (5). Additional benefits of IRS come from the habit of some malaria vectors to rest inside dwellings, using them as refugia either before or after blood-feeding (1).Despite the incontestable success of these control interventions in reducing the burden of malaria (6), a plateau in the incidence rate of malaria cases has been observed in Africa during the last years (7). This could be at least in part explained by the intensive selection pressure put up by insecticides (8). Indeed, mutations conferring insecticide resistance have rapidly emerged (9), and resistance to different classes of insecticides is presently widespread in most malaria vector populations (10, 11). Moreover, there is evidence that some vector populations are changing their behavior in response to control interventions by feeding progressively more at places and at times when humans are less likely to be protected (12, 13). So far, behavioral modifications have resulted in more biting during the evening and early morning and out-of-doors (14–21). Recent studies reporting significant amounts of daytime biting, however, remain somewhat anecdotal, with few exceptions. Overall, these modifications increase the window of opportunity for human–vector contact, producing what is called residual malaria transmission (22, 23): this expression implies that transmission will persist even if LLINs and IRS are fully effective. It is feared, therefore, that the malaria elimination target set upon current control interventions may be compromised in the long term by residual malaria transmission (24). Countering this phenomenon should be based on better knowledge of the biology and behavior of the vectors, with the aim to develop more suitable interventions (12, 23, 25).In the Central African Republic, malaria remains a major public health problem and the main cause of deaths among children <5 y old (26). In 2006, the National Malaria Control Program implemented the first phase of the Global Fund Program for Malaria based on free distribution of LLINs to pregnant women and children <5 y old, with moderate results (26, 27). A new campaign of mass LLIN distribution was deployed in 2015. Yet, malaria incidence was not significantly reduced (28). Several studies reported the presence in the country of populations of the major malaria vectors Anopheles gambiae, Anopheles coluzzii, and Anopheles funestus that are resistant to pyrethroids, the class of insecticides used for impregnation of bed nets (29–31). It is not known, however, the degree to which insecticide resistance is responsible for such moderate reductions in malaria incidence in this country, above and beyond what can be accounted for by a national health system weakened by years of civil war and unrest.In order to appreciate the potential of residual malaria transmission in this epidemiological context, we investigated the biting behavior of the malaria vectors occurring in urban settings of Bangui, Central African Republic. We implemented two significant modifications to the sampling protocol and analytical procedures that are usually applied in this kind of investigation. First, the sampling plan consisted of monthly sessions of 48-h around-the-clock collections of mosquitoes coming to feed on human hosts both indoors and outdoors. Second, the daily rhythmicity of the observed biting events was analyzed quantitatively using a circular statistics framework that models these events on a circumference rather than along the usual linear representation (32–34). Unexpectedly, we found that 20 to 30% of malaria vector biting occurred at full daytime indoors. These results suggest that current vector control interventions may not be enough to achieve sufficient reductions in malaria transmission in Bangui. Perhaps even more significant, these observations suggest that Anopheles mosquitoes may have the potential to achieve fundamental modifications in the temporal organization and circadian control of their feeding behavior, with major impacts on malaria control strategies in Africa. We elaborate these results as follows.     

Characterization of dihydropyridine binding sites in the rat brain: hypertension and age-dependent modulation of [3H](+)-PN 200-110 binding

The properties of [3H]dihydropyridine (DHP), nitrendipine and (+)-PN 200-110, binding to rat cerebral membranes were investigated. In normotensive Wistar-Kyoto (WKY) adult rats, the highest densities of [3H]DHP binding sites were found in the hippocampus. Frontal cerebral cortex and hypothalamus had intermediate levels and no specific binding of [3H]DHP and [125I]iodipine could be detected in the brainstem membranes and more precisely in the nucleus tractus solitarius and in the locus coeruleus. Changes in the maximal number of DHP binding sites (Bmax) were observed in spontaneously hypertensive rats (SHR) and in old Sprague-Dawley rats. In adult SHR, there was a significant increase in the Bmax values of [3H](+)-PN 200-110 binding in the hippocampus when compared to the values obtained in WKY. There was no difference in the Bmax values between young (3 weeks) prehypertensive SHR and age-matched WKY. In senescent (26 months) Sprague-Dawley rats, the Bmax values of [3H](+)-PN 200-110 binding were significantly reduced (30%) in the frontal cerebral cortex and the hippocampus, as compared with the number of DHP binding sites found in mature Sprague-Dawley rats (15 weeks).