Primary syphilis with a tongue ulcer mimicking tongue cancer: a case report.

The main symptom in primary syphilis is a small, painless, sore or ulcer called a chancre on the penis, vagina, or around the anus, although chancres can sometimes appear in the mouth or on the lips, fingers, or buttocks. We present the case of a man in his early 60 s with a chief complaint of a painful tongue ulcer. An ulcerated, indurated, and hemorrhagic lesion (23 × 14 mm) was found on the ventral tongue surface, near the oral floor. Palpation identified several swollen, mobile, elastic cervical lymph nodes, with no tenderness. We initially diagnosed tongue cancer; however, during a subsequent detailed examination for a malignant tumor, including biopsy and obtaining additional history, his disease was finally identified as primary syphilis with multiple swollen cervical lymph nodes. Oral amoxicillin and probenecid were started, and after 14 days, there was partial reduction in the size of the submandibular lymph nodes and the ulcer on the left tongue margin. The number of patients with syphilis in Japan increased by eight times from 2012 to 2018. We suggest that dentists consider primary syphilis as a differential diagnosis for oral refractory ulcer with induration and obtain a detailed patient history.

Insulin facilitates synaptic transmission via gap junctions between fast-spiking interneurons in the rat insular cortex.

PURPOSE: Inhibitory synaptic currents from fast-spiking neurons (FSNs), a typical gamma-aminobutyric acid (GABA)ergic interneuron in the cerebral cortex, to pyramidal neurons are facilitated by insulin. FSNs frequently show electrical synapses to FSNs, however, the effect of insulin on these electrical synapses is unknown. The aim of this study was to evaluate effects of insulin on electrical synaptic potentials between FSNs. METHODS: Electrical synaptic potentials via gap junctions between FSNs were recorded to examine how insulin modulates these potentials in the rat insular cortex (IC). RESULTS: Bath application of insulin (10 nM), which increases the spike firing rate of pyramidal neurons and unitary inhibitory postsynaptic currents recorded from FSN to pyramidal neuron connections, slightly but significantly increased electrical synaptic currents. The mean ratio of electrical synapses, the coupling coefficient that is obtained by postsynaptic voltage responses divided by presynaptic voltage amplitude, was 8.3 ± 1.1% in control and 9.2 ± 1.1% (n = 14) during 10 nM insulin application. Input resistance and voltage responses to large hyperpolarizing currents (-140 pA) were not changed by insulin. CONCLUSION: These results suggest that insulin facilitates spike synchronization by increasing electrical synaptic currents via gap junctions of GABAergic FSNs in the IC.

Asymmetrical organization of oral structures in the primary and secondary somatosensory cortices in rats: An optical imaging study.

In rodents, the representation of the body surface in the primary somatosensory cortex (S1) forms a mirror image along the ventral border of the S1 in the secondary somatosensory cortex (S2). Sensory information from the oral region is processed in the S1 and the border region between the S2 and insular oral region (IOR). We examined the relationship between somatosensory representations in the S1 and S2/IOR using optical imaging with a voltage-sensitive dye in urethane-anesthetized rats. In reference to the rhinal fissure and middle cerebral artery, we made a somatosensory map by applying electrical or air puff stimulation. The initial neural excitation in the S1 to facial structures, including the eyebrow, cornea, pinna, whisker pad, nasal tip, and nasal mucosa, spread toward the ventral area, putatively the S2. The initial cortical responses in the S1 to oral structures, including the lower lip, tongue, and teeth, were spatially separated from those in the S2/IOR. The representation of the tongue center, tongue tip, mandibular molar pulp, mandibular incisor pulp, and mandibular incisor periodontal ligament were almost linearly arranged from caudal to rostral in both S1 and S2/IOR. The lower lip was represented in the dorsal area from the representation of teeth and tongue in both S1 and S2/IOR. The representations of maxillary teeth were caudal and dorsal to the representations of mandibular teeth in the S1 and S2/IOR, respectively. These results suggest that the representation of oral structures in the S1 formed a non-mirror image, not a mirror image, in the S2/IOR.

Effectiveness of cetuximab as preemptive postsurgical therapy for oral squamous cell carcinoma patients with major risk: a single-center retrospective cohort study.

A retrospective cohort study was performed to investigate the effectiveness of preemptive postsurgical therapy with cetuximab for patients with a major risk of recurrence or metastasis after clinical complete resection of primary oral squamous cell carcinoma (OSCC). The study period was from 2007 to 2019 for patients treated at the Department of Oral and Maxillofacial Surgery, Dokkyo Medical University School of Medicine. OSCC patients with major risk (n = 88) in the follow-up period were divided into groups with no postsurgical treatment (NP group), with standard postsurgical treatment (SP group), and with postsurgical treatment including cetuximab (CP group), and prognosis were compared among those groups. The 5-year overall survival rate was significantly higher in patients who received postsurgical treatment with cetuximab (CP) compared to that in the other two groups ((CP vs. NP, p = 0.028; CP vs. SP, p = 0.042). Furthermore, we performed multivariate analysis to evaluate the effects of the main components of the treatment. Among CDDP, radiotherapy, and cetuximab, only cetuximab significantly contributed to improved survival by univariate analysis (crude HR:0.228, 95%CI:0.05-0.968, p = 0.045). cetuximab also showed the same tendency in multivariate analysis, although p value did not reach significant level (Adjusted HR: 0.233, 95%CI: 0.053-1.028, p = 0.054). The results suggest that the postsurgical treatment with cetuximab as a preemptive postsurgical therapy after complete surgical resection of a visible tumor is considerably effective for OSCC patients with major risk, in other words, invisible dormant metastasis.

Application of oxytocin with low-level laser irradiation suppresses the facilitation of cortical excitability by partial ligation of the infraorbital nerve in rats: An optical imaging study.

The effects of current treatments for neuropathic pain are limited. Oxytocin is a novel candidate substance to relieve neuropathic pain, as demonstrated in various animal models with nerve injury. Low-level laser therapy (LLLT) is another option for the treatment of neuropathic pain. In this study, we quantified the effects of oxytocin or LLLT alone and the combination of oxytocin and LLLT on cortical excitation induced by electrical stimulation of the dental pulp using optical imaging with a voltage-sensitive dye in the neuropathic pain model with partial ligation of the infraorbital nerve (pl-ION). We applied oxytocin (OXT, 0.5 µmol) to the rat once on the day of pl-ION locally to the injured nerve. LLLT using a diode laser (810 nm, 0.1 W, 500 s, continuous mode) was performed daily via the skin to the injured nerve from the day of pl-ION to 2 days after pl-ION. Cortical responses to electrical stimulation of the mandibular molar pulp under urethane anesthesia were recorded 3 days after pl-ION. Both the amplitude and area of excitation in the primary and secondary somatosensory and insular cortices in pl-ION rats were larger than those in sham rats. The larger amplitude of cortical excitation caused by pl-ION was suppressed by OXT or LLLT. The expanded area of cortical excitation caused by pl-ION was suppressed by OXT with LLLT but not by OXT or LLLT alone. These results suggest that the combined application of OXT and LLLT is effective in relieving the neuropathic pain induced by trigeminal nerve injury.

Preceding Administration of Minocycline Suppresses Plastic Changes in Cortical Excitatory Propagation in the Model Rat With Partial Infraorbital Nerve Ligation.

Neuropathic pain is known to be attributable to the injured nerve, a postoperative problem induced by surgery. The infraorbital nerve (ION), a branch of the trigeminal nerve, innervates to the facial and oral regions and conveys somatosensory information to the central nervous system. The partial ligation of ION (pl-ION) is a method to mimic chronic trigeminal neuropathic pain and behavioral abnormality. To counteract induction of such abnormal pain, the effective pharmacological treatment is desired. Although recent studies have revealed the molecular mechanisms regarding chronic pain, estimation of the effectiveness of the pharmacological treatment has not been well-provided especially in the central nervous system so far. Here we examined whether pl-ION induces plastic changes in the cerebral cortex and investigated effects of minocycline on the cortical plastic changes. We performed the pl-ION to Wistar male rats (4-5 weeks old), and confirmed a mechanical nocifensive behavior in response to the mechanical stimulation with von-Frey filaments. The withdrawal threshold to mechanical stimuli of the whisker pad was decreased 1 day (1 d) after pl-ION, which continued up to 14 d after pl-ION, suggesting that pl-ION model rats presented allodynia and enhanced the response sustained at least for 14 d after pl-ION. Next, cerebrocortical activities were evaluated 3 d after pl-ION (3d-pl-ION) by the optical imaging with a voltages-sensitive dye, RH1691, to quantify the response to electrical stimulation of the whisker pad skin, mandibular molar dental pulp, and mentum skin. Electrical stimulation to the whisker pad skin induced smaller excitation in the primary sensory cortex (S1) of 3d-pl-ION in comparison to that in the sham. In contrast, cerebral cortical responses to the mandibular molar dental pulp and mentum skin stimuli increased both in S1, and the secondary somatosensory and insular oral region (S2/IOR) after pl-ION. Administration of minocycline (30 mg/kg/d) from 1 d before to 2 d after pl-ION partially recovered the pl-ION-induced changes in cortical excitation in S1 and S2/IOR in 3d-pl-ION. These results suggest that somatosensory and insular cortical excitation is changed by pl-ION, and the preceding injection of minocycline counteracts the plastic changes in the cortical activities.

Menthol-induced facilitation of cerebrocortical excitatory propagation induced by air puff stimulation of the nasal cavity in the rat: An optical imaging study.

Temperature plays a critical role in the sensation of airflow in the nasal mucosa. Neural activities of the ethmoidal nerve, a trigeminal afferent, responding to airflow are suppressed by warm airflow, whereas cold airflow enhances the ethmoidal nerve activities, which is mimicked by application of menthol, a cold-sensitive TRPM8 receptor agonist. However, it has been an open issue how menthol modulates the spatiotemporal profiles of neural activities of somatosensory cortical neurons. In this study, we assessed neural responses to an air puff stimulation (100 ms) to the nasal cavity in the absence or presence of l-menthol using an optical imaging technique with a voltage-sensitive dye in the primary cortex (S1) of urethane-anesthetized rats. A weak air puff application (15 psi) without l-menthol induced neural excitation in a part of the contralateral S1. The air puff stimulation with l-menthol significantly increased the optical signal intensity, expanded the activated area, and shortened the latency, compared to those in the absence of l-menthol. These results suggest that activation of cold-sensitive TRPM8 receptors sharpens airflow sensation in the nasal cavity and expands the receptive field, especially toward the pharynx, which may contribute to enhanced flavor perception.

Retrospective clinical study of 296 patients with mass lesions of the tongue.

To better understand the clinical features of mass lesions of the tongue, we retrospectively evaluated frequency, recurrence rate, and complications in 296 patients who had undergone surgery for such lesions. The diagnoses were fibroma (43.6%), mucous cyst (14.2%), papilloma (11.8%), hemangioma (7.8%), granuloma (6.4%), lipoma (1.4%), schwannoma (1.0%), ectopic tonsil (0.7%), and other (13.2%). Recurrence was noted in two patients (0.7%). Twenty-two patients (7.4%) developed surgical complications, including lingual nerve paralysis (6.4%), glossodynia (0.6%), and postoperative infection (0.3%). Lingual nerve paralysis was observed in the ventral portion (42.1%) of the tongue, apex (36.8%), lateral border (10.5%), and dorsum (10.5%). When all sites were considered together, there was no significant difference in the number of patients presenting with lingual nerve paralysis (P = 0.075). However, there were significant differences in lingual nerve paralysis at the lateral border (P < 0.05), apex (P < 0.05), and dorsum (P < 0.001) but not at the ventral portion (P > 0.05) in the size of the patients with versus without it which suggests that the risk of lingual nerve paralysis is higher at the ventral tongue, regardless of tumor size. These results shed light on the clinical features of mass lesions of the tongue.

Somatotopic Organization and Temporal Characteristics of Cerebrocortical Excitation in Response to Nasal Mucosa Stimulation With and Without an Odor in the Rat: An Optical Imaging Study.

Nasal mucosa has roles in warming and humidifying inspired air and is highly sensitive to mechanical stimuli. Moreover, the upper part of the nasal mucosa expresses olfactory receptors processing olfactory information. Although the somatosensory map of the face in the primary (S1) and secondary (S2) somatosensory cortices is clearly documented, the map of the nasal mucosa and the effect of odors on their activities are largely unknown. This study aimed to identify the cortical regions in S1 and their temporal features in response to somatosensory stimulation of the nasal mucosa using an optical imaging technique in urethane-anesthetized rats. An air puff application response to nasal mucosa first occurred in a part of contralateral S1 and subsequently, spread toward the rostrally and ventrally adjacent sites. Upper pharynx stimulation initially activated this rostrally expanded site and the excitatory propagation from the initially activated region toward ventral region likely represented S2. Signal intensity and activated area increased dependent on air pressure. Nasal tip stimulation initially excited S1 region caudally adjacent to that of nasal mucosa. Moreover, the amplitude of S1 excitation was similar between air puff stimulation with and without an odor, amyl acetate. In contrast to contralateral S1, air puff stimulation with the odor showed a faint optical signal increase in the ipsilateral piriform cortex. These results suggest that somatosensory information from the nasal mucosa and skin, and upper pharynx are processed in spatially continuous regions of S1, and interaction between somatosensory and olfactory systems is relatively small in contralateral S1.