[A Case of Severe Skin Disorder during Pembrolizumab Treatment for Recurrent Maxillary Gingival Carcinoma]

Immune checkpoint inhibitors are known to produce immune-related adverse events(irAE)that require medical management. Herein, we report a case of a patient treated with pembrolizumab who experienced a Grade 3 interrupted skin disorder. The patient is a 67-year-old female diagnosed with right maxillary gingival squamous cell carcinoma(cT4aN0M0, Stage ⅣA)and underwent partial right maxillectomy, right extended supra-omohyoid neck dissection, and maxillary reconstruction using a forearm flap. Six months postoperatively, late lymph node metastases with extracapsular spread was found in the right buccal lymph node and the left neck, and the patient underwent right buccal lymphadenectomy and left modified radical neck dissection. After postoperative combined chemoradiotherapy(cisplatin plus IMRT)followed by 13 courses of cetuximab plus paclitaxel, a recurrent lesion was found in the right buccal region. After 8 courses of pembrolizumab, a skin rash appeared on the forearm, chest, and back, which was diagnosed as Grade 3 irAE, requiring hospitalization. The patient was re-instituted after waiting for improvement of the skin disorder. The pembrolizumab at 75% reduction dose was re-administrated, and the patient has been followed up so far.

Evidence of second-order transition and critical scaling for the dynamical ordering transition in current-driven vortices

Dynamical ordering from a disordered plastic flow to an anisotropically ordered smectic flow induced by a dc force has been studied in various many-particle systems, including vortices in type-II superconductors. However, it remains unclear whether the dynamical ordering is a true phase transition because of lack of suitable experimental methods. Here, we study the response of vortex flow to the transverse force using a cross-shaped amorphous Mo[Formula: see text]Ge[Formula: see text] film. From transverse current-voltage (force-velocity) characteristics under various longitudinal currents, we find a change of the transverse response in low voltage (velocity) regions from a nonlinear to linear behavior at a well-defined longitudinal current that marks the dynamical ordering transition. We also find the scaling collapse of the transverse current-voltage curves to a universal scaling function, providing evidence of the second-order transition for the dynamical ordering transition.

[Effect of the Hyoid Bone Suspension Technique on the Preservation of Swallowing Function after Total Glossectomy and Pectoralis Major Musculocutaneous Flap Reconstruction for Locally Advanced Tongue Cancer]

Dysphagia is a major postoperative complication in patients with locally advanced oral cancer. In this case report, we describe the effect of the hyoid bone suspension technique on the preservation of swallowing function after total glossectomy and pectoralis major musculocutaneous flap reconstruction for locally advanced tongue cancer. Case: A 72-year-old Japanese male was diagnosed with advanced squamous cell carcinoma on the left side of his tongue(cT4aN2cM0, cStage ⅣA). Under general anesthesia, the patient underwent a tracheotomy, bilateral modified radical neck dissection type Ⅲ, total glossectomy, and reconstruction with a left pectoralis major musculocutaneous flap(PMMC flap). Intraoperatively, the PMMC flap was designed to have a heart shape of 11×6 cm and was elevated. Subsequently, holes were made at the lower edge of the mandible, and the hyoid bone was suspended and fixed to the mandibular border using 2-0 nylon sutures. The postoperative course was uneventful; the flap was completely engrafted and was in good condition. The hyoid bone suspension technique can reproduce the pharyngeal phase of swallowing, and the palatal augmentation prosthesis helps to improve food mass feeding and preserve the swallowing function.

[Two Cases of Advanced Lower Gingival Carcinoma Treated Surgically Using a Novel Patient-Specific Full Custom- Made Mandibular Reconstruction Plate System]

The treatment of advanced lower gingival carcinoma requires postoperative chemoradiotherapy; therefore, simultaneous hard-tissue reconstruction may not be indicated. In these cases, mandibular reconstruction is performed using a temporal reconstruction plate and various skin flaps. Herein, we reported 2 cases of advanced lower gingival carcinoma treated with a novel computer-assisted patient-specific, fully custom-made mandibular reconstruction plate system(Cosmofix®)in combination with a pedicle/free flap. In case 1, an 80-year-old female patient was diagnosed with right lower gingival carcinoma( cT4aN3bM0, Stage ⅣB). Under general anesthesia, she underwent tracheostomy, bilateral neck dissection, segmental mandibulectomy, and mandibular reconstruction using Cosmofix® in combination with an ulnar forearm free flap. In case 2, an 81-year-old male patient was diagnosed with right lower gingival carcinoma(cT4aN2bM0, Stage ⅣA). The patient underwent maintenance dialysis and required minimally invasive surgery using a pedicle flap. Under general anesthesia, the patient underwent tracheostomy, right modified radical neck dissection, segmental mandibulectomy, and mandibular reconstruction using Cosmofix® in combination with a pectoralis major myocutaneous flap. Postoperative facial morphology, occlusion, eating, swallowing, articulation, and other dysfunctions were minimal in both the cases. Adjuvant chemoradiotherapy was recommended. In conclusion, the utilization of the Cosmofix® system enabled both esthetic and functional reconstruction following segmental mandibulectomy for advanced lower gingival carcinoma.

[A Case of Recurrent Tongue Cancer in a Patient of AYA Generation Who Underwent Salvage Surgery and Oral-Maxillofacial Reconstruction after Super-Selective Intra-Arterial Chemoradiotherapy]

Radical tumor resection for oral cancer can cause morphological and esthetic disorders and oral and maxillofacial dysfunction and maintaining a social life could become challenging, especially in the adolescents and young adults(AYA)generation. Conversely, chemoradiotherapy for young patients may cause adverse reactions such as impaired fertility and late side effects of radiation. Therefore, treatment should be performed cautiously. We report a case of AYA generation patient who underwent salvage surgery and maxillofacial reconstruction for recurrent tongue cancer after super-selective intra-arterial chemoradiotherapy. The patient was a 30-year-old woman who was 20 weeks pregnant. She was diagnosed with Stage Ⅲ squamous cell carcinoma of the right tongue, cT3N0M0. After abortion, the patient underwent super-selective intra-arterial chemoradiotherapy and achieved a complete response. However, 13 years later, a recurrence of Stage ⅣA tongue cancer, r- cT4aN2bM0, was reported. Additionally, the patient had osteoradionecrosis. We performed radical tumor resection(bilateral neck dissection plus subtotal glossectomy plus segmental mandibulectomy)and maxillofacial reconstruction with a fibula flap. Subsequently, we performed occlusal reconstruction treatment using dental implants. Three years postoperatively, no tumor recurrence was observed, and the patient was satisfied with the restored morpho-aesthetic and maxillo-oral functions.

A rare case of dentinogenic ghost cell tumor with concomitant odontoma

Key Clinical Message

A case of dentinogenic ghost cell tumor occurring simultaneously with a clinically diagnosed odontoma. The occurrence of epithelial and mesenchymal tumors at the same site is very rare, but should be kept in mind during pathological diagnosis.

Abstract

Dentinogenic ghost cell tumor (DGCT) is a rare and benign odontogenic tumor composed of ghost cells, calcified tissue, and dentin. We present an extremely rare case of a 32-year-old female who was clinically diagnosed with an odontoma presenting with a painless swelling in her maxilla. Radiographic examination showed a well-defined radiolucent lesion with tooth-like calcified areas. The tumor was resected under general anesthesia. No recurrence was noted at the 12-month follow-up. Histopathological examination of the surgically resected tumor yielded a diagnosis of DGCT with odontoma.

Postoperative Complications following Open Reduction and Rigid Internal Fixation of Mandibular Condylar Fracture Using the High Perimandibular Approach

The high perimandibular approach is a feasible surgical technique for treating mandibular condylar fractures with open reduction and internal fixation, followed by fewer complications. Temporary trismus is the only postoperative complication that may occur. This study evaluated postoperative complications following open reduction and rigid internal fixation (OR-IF) of mandibular condylar fractures using the high perimandibular approach. Twenty consecutive patients undergoing OR-IF were included in this study. They included 11 male and 9 female patients, of an average age of 58.5 years, all of whom responded to a follow-up call at least 12 months after the surgery. All patients were evaluated for range of mouth opening, postoperative complications, and radiological findings. A statistical analysis of the relationship between range of mouth opening and related clinical parameters at 6 months postoperative evaluation was conducted. The fracture of the condylar neck was associated with a limited range of mouth opening and longer operation time. However, longer operation time was not associated with a limited range of mouth opening. The high perimandibular approach with OR-IF in mandibular condylar fractures is a feasible and safe technique; however, prolonged surgery and mandibular condylar neck fractures could affect the postoperative range of mouth opening.

[A Case of Reconstruction of the Osteoradionecrosis of the Jaw Using the Patient-Specific Custom-Made Cutting Guide and Mandibular Reconstruction Plate]

Multidisciplinary treatment, combining ablative surgery and reconstruction, radiotherapy, and chemotherapy, is used to treat advanced oral cancers. In this study, we report a case of extensive osteoradionecrosis of the mandible following multidisciplinary treatment for tongue cancer, in which a computer-assisted, patient-specific custom-made cutting guide and reconstruction plate(TruMatch® )were used to improve the patient's facial morphology and oral-maxillofacial functioning. A 70-year-old man received multidisciplinary treatment for squamous cell carcinoma of the left side of the tongue (cT3N2bM0, cStage ⅣA)at a previous hospital. Seven years postoperatively, bilateral osteoradionecrosis of the mandible developed, and the patient was referred to our department for further treatment. Since the lesions were extensive, we planned reconstructive surgery using the TruMatch® system in collaboration with the plastic surgery department of our hospital. Surgery was performed precisely and accurately according to the preoperative simulation. Postoperatively, the patient's recovery was uneventful. The TruMatch® system enables us to achieve good morphological and comprehensive functional oral-maxillofacial reconstruction.

[A Case of Tongue Carcinoma with Malignant Transformation Caused by the Pandemic]

In April 2020, a state of emergency was declared because of the pandemic, and the public was instructed to refrain from leaving their homes. Consequently, this stirred up anxiety about visiting medical institutions. Here, we describe a case of tongue carcinoma that developed from an oral precancerous lesion into a malignant transformation owing to the effects of refraining from medical examinations caused by the pandemic. The patient was a 62-year-old woman. In March 2020, the patient became aware of a mass at the tongue's margin and was referred to our department. An excisional biopsy was performed, and a diagnosis of inflammatory change was made. The following month, a white ulcerative lesion was found, and another excisional biopsy was performed; therefore, a diagnosis of left tongue leukoplakia without epithelial dysplasia was made. The patient was scheduled for surgery; however, refused treatment and consultation because of the pandemic. In September 2021, the patient revisited our department on her own volition because an ulcerative lesion with indistinct borders and induration was found at the left lingual margin. Upon close examination, a diagnosis of left tongue squamous cell carcinoma(cT2N2bM0, Stage ⅣA)was made. In October 2021, radical tumor resection and reconstruction were performed. After 8 months postoperatively, the patient is currently well.

[Oral Function Restoration via Two-Stage Reconstructive Treatment of an Extensive Maxillary Defect Following Maxillectomy]

Recently, the number of survivors that had oral cancer has increased, but deterioration in the quality of life of patients concerning oral function and cosmetic appearance has become problematic. Prosthodontic dentures usefully treat jaw defects after maxillary resection for cancer, but advances in microsurgery have rendered the possibility to reconstruct maxillary defect and oral cavity using a microvascular flap. Here, we describe 2-stage treatment after 35 years postoperatively. We restored the maxillofacial function using microvascular flaps and partial denture. The patient was a 59-year-old woman who underwent left lateral maxillectomy 35 years previously to treat an advanced left maxilla gingival carcinoma. A maxillary prosthesis was applied, requiring repeated adjustments and refabrications. The patient visited to obtain improvements for oral and maxillofacial functions and long-term quality of life. The left maxillary bone defect was 45×50 mm in area. Collaborating with the Department of Plastic and Reconstructive Surgery, the patient underwent reconstructive treatment using a microvascular forearm flap and partial denture. The patient's progress was excellent; eating, swallowing, and articulation improved. For 1 year postoperatively, the patient was satisfied with the results.

[A Case of Lower Gingival Carcinoma Treated Surgically Using Computer-Assisted Patient-Specific Cutting Guide and Mandibular Reconstruction Plate]

We report a case of advanced lower gingival carcinoma treated with a computer-assisted custom-made surgical guide and reconstruction plate system(TruMatch®)in combination with a pectoralis major myocutaneous flap. In a 74-year-old male patient, a neoplastic lesion with a 30×30 mm periapical induration was observed around an extraction socket of left mandibular third molar. After various examinations, we diagnosed lower gingival carcinoma(cT4aN2bM0, Stage ⅣA). The patient was a paraplegic with a spinal cord injury, and reconstruction of mandible with free flap was not indicated, requiring minimally invasive surgery. Therefore, a surgical guide and reconstruction plate were prepared preoperatively using the Tru- Match® system. Under general anesthesia, the patient underwent tracheostomy, left modified radical neck dissection, segmental mandibulectomy, and reconstruction of the mandible using this system in combination with a pectoralis major myocutaneous flap. Postoperatively, the patient had minimal dysfunction. Currently, at 18 months follow up postoperatively, good prognosis was observed. In conclusion, this is a useful surgical system with accurate and less invasive surgery for segmental mandibulectomy of advanced lower gingival carcinoma.

Kibble-Zurek Mechanism for Dynamical Ordering in a Driven Vortex System

The Kibble-Zurek mechanism describes the formation of topological defects in systems crossing a continuous symmetry-breaking phase transition at a finite quench rate. While this mechanism has been extensively studied for equilibrium transitions, its applicability to nonequilibrium transitions has not yet been fully examined. Recent simulation has shown the applicability of the Kibble-Zurek mechanism to dynamical ordering transitions in particlelike assemblies, including superconducting vortices, driven over random disorder. Here, we experimentally study the configurational order of vortices in the course of dynamical ordering with various quench rates. We verify a power-law scaling of the defect density with the quench rate and an impulse-adiabatic crossover on the ordered side of the transition, which are key predictions of the Kibble-Zurek mechanism. Our results suggest the applicability of the Kibble-Zurek mechanism to other nonequilibrium phase transitions.

Oral Dysfunction in Patients with Oral Cancer Could Occur Before Treatment and Require Early Nutritional Improvement: A Cross-Sectional Study

Patients with oral cancer have poor nutritional status before treatment. However, there have been no reports of the detailed evaluation of preoperative oral function in patients with oral squamous cell carcinoma (OSCC). Therefore, this study aimed to evaluate the preoperative oral function of patients with OSCC and examine the relationship with nutritional status. Oral function measurements (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function, Eating Assessment Tool, and Postoperative Oral Dysfunction Scale) and Mini Nutritional Assessment-Short Form (MNA-SF) data were collected from 51 patients with OSCC (men: 37, women: 14, mean age: 72.1 years) who visited the Shimane University Hospital, Department of Oral and Maxillofacial Surgery, from September 2019 to September 2021. The tongue was the most prevalent primary gingiva site [22 patients (43.1%)], and 36 patients (70.6%) had advanced cancer. Comparisons between nutritional status and each related factor revealed significant differences in the number of individuals in the household, cancer stage, presence of pulmonary disease, number of teeth, microorganisms (grade), and masticatory function (mg/dL) (p < 0.05). Multiple regression analysis using the total MNA-SF score as the dependent variable with adjustment for confounding factors showed significant association between oral dryness and tongue pressure (p < 0.05). No significant association was found for the Eating Assessment Tool or Postoperative Oral Dysfunction scale. Patients with OSCC may have decreased oral function because of the tumor at the time of diagnosis, which causes a decline in nutritional status. Preoperative interventions are necessary to improve nutrition based on the state of oral function.

Oral functional impairment may cause malnutrition following oral cancer treatment in a single-center cross-sectional study

Oral dysfunction and dysphagia after oral cancer treatment are linked to altered nutritional status. We aimed to identify specific oral functions related to nutritional status. We conducted a cross-sectional study from September 2019 to December 2021, recruited 75 participants (median age: 72.0 years), including 52 males and 23 females, collected background data, and evaluated oral function. The Mini Nutritional Assessment-Short Form (MNA-SF) scores were divided into three groups (normal nutritional status, at risk of malnutrition, and malnourished), and a multi-group comparison was conducted for each oral function measurement (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function, and Eating Assessment Tool [EAT-10]). The primary tumor site was the tongue in 31 patients (41.3%), gingiva in 30 (40.0%), and others in 14 (18.7%). Multiple comparisons revealed significant differences in occlusal force, tongue pressure, masticatory function, and EAT-10 levels, categorized as Type I (Transport type) and Type III (Occlusion type) postoperative oral dysfunctions, between each MNA-SF group. Multiple regression analysis showed a statistically significant association with MNA-SF in terms of masticatory function and EAT-10 levels, categorized as Type I. Type I and Type III are risk factors for malnutrition, confirming that different types of postoperative oral dysfunction require unique nutritional guidance.

Discrepancy between subjective and objective postoperative oral dysfunction assessment after oral cancer treatment: A single-center cross-sectional study

OBJECTIVES

It has been reported that in many cancer types, the evaluation of complications and side effects of treatment differs between subjective and objective evaluations. The purpose of this study is to verify whether the evaluation of postoperative oral dysfunction following oral cancer treatment was consistent subjective and objective evaluations.

MATERIALS AND METHODS

This cross-sectional study collected background data and evaluated the oral function (microorganisms, oral dryness, occlusal force, tongue pressure, masticatory function and eating assessment tool [EAT-10]) of 75 patients from September 2019 to December 2021. The postoperative oral dysfunction-10 (POD-10) was used for the subjective assessment of dysfunction in oral cancer patients. Also, Matsuda-Kanno classification was used for the objective assessment. The kappa coefficient between POD-10 and oral dysfunction was calculated for the degree of agreement. The relationship between oral function measurements and POD-10 was examined by multiple regression analysis.

RESULTS

The patients' median age was 72.0 (25-75 percentile: 64.0-78.0) and 69.3% were male. The kappa coefficients indicating the degree of agreement with POD-10 were 0.41 (P < 0.01) for occlusal force, 0.27 (P = 0.01) for masticatory function, and 0.59 (P < 0.01) for EAT-10. Multiple regression analysis showed a significant association of occlusal force (β = -0.33, P = 0.03) and EAT-10 (β = 0.80, P < 0.01) with POD-10.

CONCLUSIONS

For postoperative oral dysfunction type III (occlusal type), the evaluations of subjective and objective evaluations tended to be consistent. However, for type I (transport type) and II (oral hygiene type), these evaluations may be prone to overestimation or underestimation by either the medical professional or the patient.

Critical behavior of nonequilibrium depinning transitions for vortices driven by current and vortex density

We study the critical dynamics of vortices associated with dynamic disordering near the depinning transitions driven by dc force (dc current I) and vortex density (magnetic field B). Independent of the driving parameters, I and B, we observe the critical behavior of the depinning transitions, not only on the moving side, but also on the pinned side of the transition, which is the first convincing verification of the theoretical prediction. Relaxation times, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau (I)$$\end{document}τ(I) and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau (B)$$\end{document}τ(B), to reach either the moving or pinned state, plotted against I and B, respectively, exhibit a power-law divergence at the depinning thresholds. The critical exponents of both transitions are, within errors, identical to each other, which are in agreement with the values expected for an absorbing phase transition in the two-dimensional directed-percolation universality class. With an increase in B under constant I, the depinning transition at low B is replaced by the repinning transition at high B in the peak-effect regime. We find a trend that the critical exponents in the peak-effect regime are slightly smaller than those in the low-B regime and the theoretical one, which is attributed to the slight difference in the depinning mechanism in the peak-effect regime.

[A Case of Polymorphous Low-Grade Adenocarcinoma of the Palate]

Polymorphous low-grade adenocarcinoma(PLGA)is a relatively rare low-grade adenocarcinoma of the minor salivary glands. If radical resection is performed, the prognosis is favorable. We present the case of a 62-year-old woman who presented to our clinic in April 2019 after noticing a mass on her palate. The intraoral examination revealed a 10-mm-diameter, well-defined, tender mass extending from the right hard palate to the soft palate. We suspected a benign tumor originating from the area of transition between the hard and soft palates. An excisional biopsy of the mass was performed, and PLGA was diagnosed on the basis of histopathologic findings. In May 2019, the tumor was resected under general anesthesia and a soft palatal lift prosthesis was applied for functional recovery. In July 2020, the soft palate defect was repaired using an ulnar forearm free flap during a two-stage reconstruction procedure. The patient developed complete necrosis of the free flap, and the defect was re-reconstructed using a buccinator-based myomucosal flap. There was no evidence of disease recurrence or metastasis. Two years have passed since the initial surgery, and the patient's clinical course has been well so far.

[Mass Screening of Oral Cancer in Eastern Shimane Prefecture during 2015-2019]

The Department of Oral and Maxillofacial Surgery, Shimane University Faculty of Medicine, has been conducting mass screening of oral cancer using oral abrasion cytology by oral surgeons in eastern Shimane prefecture for public awareness and its early detection. As a result, 3(0.09%)cases of oral cancer were identified. Case 1: The patient was diagnosed with well-differentiated squamous cell carcinoma in the floor of the mouth(pT1N0M0, Stage Ⅰ)after undergoing Matsue city oral cancer screening in 2016. Case 2: The patient underwent oral cancer screening in Izumo city in 2018 and was diagnosed with verrucous carcinoma in the back of the tongue(pT1N0M0, Stage Ⅰ). Case 3: The patient was diagnosed with highly differentiated squamous cell carcinoma of the palate(pT1N0M0, Stage Ⅰ)after undergoing the Izumo city oral cancer screening in 2019. Awareness of oral cancer is important, and cancer screening by oral surgeons using cytology is highly useful and should be continued in the future.

[A Case of Treatment Applicable to Squamous Cell Carcinoma of the Tongue by Mass Screening Examination of Oral Cancer in Western Part of the Shimane Prefecture]

Radical excision, a common oral cancer treatment, produces variable postoperative results depending on the specialized tissues involved and the extent of the cancer. Furthermore, the material selected for reconstruction also influences functional outcomes. Oral dysfunction due to postoperative tissue loss is more common with advanced cancer; therefore, early detection and treatment are important. To improve oral cancer awareness and early detection, mass oral cancer screenings led by maxillofacial surgeons in cooperation with the Shimane prefecture and local dental associations were conducted. We describe the mass screening methods and describe a case of tongue cancer that was detected and treated as a result of our screening efforts.

[A Clinical Study of Orofacial Defect Reconstruction Using a Modified Submental Island Flap following Oral Cancer Resection]

INTRODUCTION

Pedicled flaps are used in orofacial defect reconstruction in older patients and patients with underlying diseases. The submental island flap(SIF)is one type of cervical pedicled flap; however, the modified submental island flap (MSIF), which includes mylohyoid muscle, is a simpler and safer type. Here, we report a clinical study of orofacial defect reconstruction using the MSIF following oral cancer resection.

PATIENTS AND METHODS

From January 2019 to December 2020, we retrospectively examined 10 cases of reconstruction using the MSIF following oral squamous cell carcinoma resection.

RESULTS

The study population consisted of 7 men and 3 women with a mean age of 76.0(66-88)years. The primary sites were lower gingiva(n=5), tongue(n=3), and buccal mucosa in(n=2). Surgical procedures included marginal mandibulectomy( n=3), segmental mandibulectomy(n=1), partial glossectomy(n=2), hemiglossectomy(n=1), buccal mucosa resection(n=2), and combined partial glossectomy and segmental mandibulectomy(n=1). The average flap size was 61.4×36.0 mm. The average time of flap elevation was 32.4(23-50)minutes. During orofacial surgery using the MSIF, organs adjacent to the primary site could also be reconstructed. There were no complications in any patients.

CONCLUSION

The MSIF is useful for orofacial defect reconstruction in older patients and patients with underlying diseases.

[Functional Recovery following Incisional Cheiloplasty for Lower Labial Edema That Developed after Bilateral Neck Dissection and Postoperative Chemoradiotherapy-A Case Report]

We report a case of functional recovery following incisional cheiloplasty for the management of lower labial edema that developed after bilateral neck dissection with preservation of the one-side internal jugular vein and postoperative chemoradiotherapy. An 81-year-old woman underwent partial maxillectomy for the treatment of maxillary gingival cancer(squamous cell carcinoma, cT1N0M0, Stage Ⅰ)in April 2013. In July 2013, she underwent bilateral neck dissection(right, modified; left, radical)for bilateral cervical lymph node recurrence with an extra-nodal spread and received postoperative chemoradiotherapy( CDDP 75 mg/m2×3 course and total radiotherapy dosage of 66 Gy). Thereafter, the patient's condition progressed without recurrence or metastasis; however, the lower labium became edematous, and severe labial dysfunction was observed. Therefore, lower labial incisional cheiloplasty was performed under local anesthesia in October 2020. An excision area of 160×14 mm was determined on the inner side of the lower labium, and excision was performed with a steel blade scalpel. Lip closure became possible one week after the operation. Seven months after the operation, the patient recovered labial function and was satisfied with the outcome.

[A Case of Recurrent Squamous Cell Carcinoma of the Mandibular Gingiva Around a Mandibular Dental Implant]

Extensive bimaxillary bone support devices(hereafter referred to as a dental implant)are useful for morphological and functional reconstruction after resection of oral cancer. However, tumor recurrence due to peri-implantitis may occur. In this report, we describe a case of squamous cell carcinoma(SqCC)recurrence around a mandibular dental implant. An 80-year- old female patient underwent tumor resection and stratification for SqCC extending from the left lingual margin to the gingiva of the left lower molar in 2013. In 2014, 2 dental implants were placed in the bilateral mandibular canine region and a prosthetic device of implant-overdenture was installed. Six years after the primary tumor resection, a mass lesion was found in the peri-implant area of the left mandibular canine. Upon examination, the patient was diagnosed with SqCC recurrence and underwent radical tumor resection and immediate reconstruction using a submental flap and a reconstruction plate. Additional dental implants were concurrently placed in the remaining mandible. There was no evidence of recurrence, and the patient remains under careful observation so far.

Development of a Subjective Symptom Rating Scale for Postoperative Oral Dysfunction in Patients with Oral Cancer: Reliability and Validity of the Postoperative Oral Dysfunction Scale-10

Currently, there is no scale to subjectively assess postoperative oral dysfunction in patients with oral cancer. The purpose of this study was to evaluate the reliability and validity of the Postoperative Oral Dysfunction Scale (POD-10) that we developed. Between September 2019 and August 2021, 62 eligible oral cancer patients (median age, 72 years; 42 men and 20 women) were enrolled in the study. The Cronbach’s alpha coefficient, which indicates the internal consistency of the scale, was 0.94, and the intraclass correlation coefficient, which indicates reproducibility, was 0.85 (95% confidential interval: 0.40–0.96, p < 0.05). Concurrent validity testing showed a statistically significant correlation between POD-10 and Eating Assessment Tool (EAT-10) (r = 0.89, p < 0.05). To test discriminant validity, statistically significant differences were found between early-stage cancer (stage I and II) and advanced-stage cancer (stage III and IV) (p < 0.05). Twenty-four points were calculated as the cutoff value for POD-10 using receiver operating characteristic analysis to calculate the cutoff value. The POD-10 was shown to be a clinically reliable and valid scale that can be used to subjectively assess postoperative oral dysfunction in patients with oral cancer and is expected to be used as a simple diagnostic tool.

Critical behavior of density-driven and shear-driven reversible-irreversible transitions in cyclically sheared vortices

Random assemblies of particles subjected to cyclic shear undergo a reversible–irreversible transition (RIT) with increasing a shear amplitude d or particle density n, while the latter type of RIT has not been verified experimentally. Here, we measure the time-dependent velocity of cyclically sheared vortices and observe the critical behavior of RIT driven by vortex density B as well as d. At the critical point of each RIT, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$B_{\mathrm {c}}$$\end{document}Bc and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_{\mathrm {c}}$$\end{document}dc, the relaxation time \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau $$\end{document}τ to reach the steady state shows a power-law divergence. The critical exponent for B-driven RIT is in agreement with that for d-driven RIT and both types of RIT fall into the same universality class as the absorbing transition in the two-dimensional directed-percolation universality class. As d is decreased to the average intervortex spacing in the reversible regime, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau (d)$$\end{document}τ(d) shows a significant drop, indicating a transition or crossover from a loop-reversible state with vortex-vortex collisions to a collisionless point-reversible state. In either regime, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\tau (d)$$\end{document}τ(d) exhibits a power-law divergence at the same \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$d_{\mathrm {c}}$$\end{document}dc with nearly the same exponent.

Postoperative oral dysfunction following oral cancer resection and reconstruction: A preliminary cross-sectional study

OBJECTIVES

Oral cancer treatment reportedly causes decreased oral function, but few studies have examined the effects of oral cancer treatment on oral function in depth. This study aimed to comprehensively evaluate the oral function after treatment and classify the conditions related to oral dysfunction in patients with oral cancer.

MATERIALS AND METHODS

We recruited participants, collected their background data, and evaluated their oral function from September 2019 to March 2021. Principal component analysis was used to identify the components of oral function measurement and oral health perception. Receiver operating characteristic analysis was performed to investigate the accuracy of oral function measurements in predicting oral intake and nutritional status.

RESULTS

Fifty patients treated for oral cancer, including 33 (66.0%) males and 17 (34.0%) females, were included. Their median age was 71.0 years (interquartile range: 63.0-76.0). There were significant differences in oral dryness between males and females, occlusal force among different age groups, tongue pressure based on the tumor stage and performance of reconstructive procedures, and masticatory function and Eating Assessment Tool scores based on whether radiotherapy was performed (P < 0.05). The principal component analysis proposed that oral function measurements and subjective oral health perception could be divided into three main components (transport, oral hygiene, and occlusion type), which explain 61.5% of the variance of the phenomenon.

CONCLUSION

A significant decrease in oral function after oral cancer treatment should be diagnosed as postoperative oral dysfunction. Postoperative oral dysfunction can be classified into three types, each of which may present with different pathologies.

Relationship between Oral Bacterial Count and Postoperative Complications among Patients with Cardiovascular Disease Treated by Surgery: A Retrospective Cohort Study

In this retrospective observational study, we evaluated the relationship between perioperative oral bacterial counts and postoperative complications in cardiovascular disease (CVD) patients. From April 2012 to December 2018, all patients scheduled for surgery received perioperative oral management (POM) by oral specialists at a single center. Tongue dorsum bacterial counts were measured on the pre-hospitalization day, preoperatively, and postoperatively. Background data were collected retrospectively. Among the 470 consecutive patients, the postoperative complication incidence rate was 10.4% (pericardial fluid storage, n = 21; postoperative pneumonia, n = 13; surgical site infection, n = 9; mediastinitis, n = 2; and seroma, postoperative infective endocarditis, lung torsion, and pericardial effusion, n = 1 each). Oral bacterial counts were significantly higher in the pre-hospitalization than in the pre- and postoperative samples (p < 0.05). Sex, cerebrovascular disease, and operation time differed significantly between complications and no-complications groups (p < 0.05). Multivariate analysis with propensity score adjustment showed a significant association between postoperative oral bacterial count and postoperative complications (odds ratio 1.26; 95% confidence interval, 1.00–1.60; p = 0.05). Since the development of cardiovascular complications is a multifactorial process, the present study cannot show that POM reduces complications but indicates POM may prevent complications in CVD patients.

Quantum Criticality inside the Anomalous Metallic State of a Disordered Superconducting Thin Film

The field-induced superconductor-insulator transition (SIT) in two-dimensional (2D) systems is a famous example of a quantum phase transition. However, an emergence of an anomalous metallic state induced by field has been a long-standing problem in 2D superconductors. While theories predicted that the emergence is attributed to strong phase fluctuations of the superconducting order parameter due to quantum fluctuations, usual resistance measurements have not probed them directly. Here, using Nernst effect measurements, we uncover superconducting fluctuations in the vicinity of the field-induced metallic state in an amorphous Mo_{x}Ge_{1-x} thin film. The field range where the vortex Nernst signals are detectable remains nonzero toward zero temperature, and it locates inside the metallic state defined by the magnetoresistance, indicating that the metallic state results from quantum vortex liquid (QVL) with phase fluctuations due to quantum fluctuations. Slow decay of transport entropy of vortices in the QVL with decreasing temperature suggests that the metallic state originates from broadening of a quantum critical point in SIT.

[Secondary Maxillofacial Revision Reconstruction Using Custom-Made Artificial Bone Following Resection of Primary Intraosseous Mandibular Squamous Cell Carcinoma and Microvascularized Fibula Flap Reconstruction]

The basic treatment for oral cancer is radical tumor resection and reconstruction, which alters the maxillofacial morphology and causes dysfunction. Reconstructive surgery can be performed with bone and soft tissue transplantation, but it is invasive and good morphological repair is difficult. Custom-made artificial bone(CT-BoneTM)consisting of calcium-deficient hydroxyapatite was newly authorized for clinical use in April 2018. It enables precise, minimally invasive maxillofacial bone reconstruction. Here, we report favorable facial morphological improvement using CT-BoneTM in a patient with maxillofacial asymmetry following the resection of a primary intraosseous mandibular squamous cell carcinoma and microvascularized fibula flap reconstruction. The patient was a 52-year-old woman. In August 2010, she was diagnosed with primary intraosseous mandibular squamous cell carcinoma of the right mandible(T4aN0M0, Stage ⅣA)and underwent mandibular segmental resection, neck dissection, and free fibula flap reconstruction. Although her clinical course was uneventful, she wanted maxillofacial esthetic correction. Therefore, we performed maxillofacial revision reconstruction using computer-simulated custom-made CT-BoneTM in January 2020. It was stably fixed to the reconstructed mandible with bioactive/bioresorbable screws. The postoperative course was uneventful and maxillofacial symmetry was obtained to the patient's satisfaction at the 6 months follow-up.

[A Case of Early Detection and Treatment Applicable to Squamous Cell Carcinoma of the Palate Detected by Oral Cancer Mass Screening in Izumo 2019]

Treatment of oral cancer is based on radical resection and reconstructive surgery. Surgery causes impairment of maxillofacial morphology and function, including chewing and eating difficulties, and dysarthria. It is necessary to restore the maxillofacial morphology and function by reconstructive surgery and use of prostheses. Therefore, early detection and treatment are required to reduce these disabilities associated with oral cancers. Here, we report a case of oral cancer that was detected early by our oral cancer mass screening program in Izumo, Japan, in 2019. A 73-year-old woman presented with a reddish ulcerative region in the palate. Cytological screening indicated positive-suspected low squamous intraepithelial neoplasia (LSIL). The patient was diagnosed as squamous cell carcinoma of the palate(cT1N0M0, StageⅠ)in our hospital. We performed radical resection of the palate tumor and immediate reconstruction using a vascularized radial forearm flap. The clinical course was good and oral function was fully restored. It is important for oral surgeons to publicize and raise awareness of oral cancer, and to continue oral cancer mass screening programs.

[Surgical Procedure for Postoperative Reconstruction of Swallowing Function in a Very Elderly Patient with Advanced Tongue Cancer]

Surgical ablation and reconstruction are the first-line treatment strategies for squamous cell carcinoma of the tongue. However, locally advanced cases can be complicated by postoperative dysphagia. Here, we report a case of advanced tongue cancer in a very elderly patient who regained good swallowing function following a reconstructive surgery using a pectoralis major musculocutaneous flap with elevation of the hyoid bone. Case: An 89-year-old man diagnosed with advanced squamous cell carcinoma of the tongue(cT4aN2bM0, cStage ⅣA)underwent tracheostomy, right modified radical neck dissection type Ⅱ, left supraomohyoid neck dissection, subtotal glossectomy, and pectoralis major musculocutaneous flap reconstruction under general anesthesia. Intraoperatively, holes were created in the lower edge of the mandible, and the hyoid bone was suspended and fixed to the mandibular border using 2-0 nylon sutures. The postoperative course was uneventful. The flap had been completely engrafted and was in a good condition. The pharyngeal stage of swallowing function was reproduced through a reconstructive surgery with suspension and fixation of the hyoid bone toward the border of the mandible. Video fluorography 6 months postoperatively showed that good swallowing function was achieved using a palatal augmentation prosthesis.

[Effective Treatment of Ameloblastoma in an Odontogenic Cyst with Fenestration before Curative Surgery-A Case Report]

Ameloblastoma is a benign odontogenic tumor that rarely undergoes malignant transformation and metastasis but may be locally invasive and recurrent. Fenestration is used to reduce maxillary odontogenic cysts. Here, we report a case ofameloblastoma that developed in the wall of an odontogenic cyst and was treated with fenestration before curative surgery. A 57-yearold Japanese man presented with a mass on the right side ofthe lower gingiva. Computed tomography revealed a unicystic lesion in the right mandibular body, accompanied by a multicystic area in the right lower canine region. Three involved molars were extracted and the cystic wall was harvested. Biopsy analysis revealed an odontogenic cyst in the unicystic lesion and an ameloblastoma in the multicystic area. The ameloblastoma was thought to have developed in the odontogenic cyst wall. The biopsy wound was maintained as a fenestration for 3 months and the lesion was reduced. Marginal resection of the mandible with cystectomy was performed to preserve mandibular bone continuity and the mandibular nerve. Although fenestration delayed curative surgery, the large cystic lesion reduction helped to avoid complications after curative surgery.

Navigation-Assisted Isolated Medial Orbital Wall Fracture Reconstruction Using an U-HA/PLLA Sheet via a Transcaruncular Approach

Purpose: We investigated the feasibility of isolated medial orbital wall fracture reconstruction using an unsintered hydroxyapatite particles/poly L-lactide (u-HA/PLLA) sheet implant with the assistance of intraoperative navigation via the transcaruncular approach. Patients and methods: Ten consecutive patients (5 males and 5 females; mean age, 57.5 years) were included based on the clinical and imaging criteria. All patients underwent surgical treatment of the isolated medial orbital wall fracture using transcaruncular incision and the u-HA/PLLA implant under navigation. The follow-up time was greater than 6 months. Preoperative and postoperative clinical data regarding the presence of diplopia, eye motility restriction, and enophthalmos were assessed. The orbital volumes of the injured and uninjured orbit were also evaluated using computed tomography images. Results: All patients had improved ophthalmologic functional and esthetic outcomes and were successfully treated without any long-term complications arising during follow-up. There was a significant difference between the preoperative and postoperative injured orbits due to herniation of the orbital contents. Moreover, the orbital volume of the postoperative injured side following surgery was the same as that of the unaffected side, indicating that anatomically good reconstruction had been obtained. Conclusions: Surgical treatment using the transcaruncular approach and u-HA/PLLA materials with intraoperative navigation is a safe, promising, and effective technique for isolated medial orbital wall fracture reconstruction.

[A Case of Medical Leech Therapy for Venous Congestion Following Forearm Flap Reconstruction]

Leeches have been used for medical treatment for at least 2,500 years. Plastic surgeons have recently begun to use leeches to reduce venous congestion after flap reconstruction. However, few reports of leech use in the oral region have been published. We report a case of medical leech therapy used to treat venous congestion after forearm flap reconstruction for oral cancer. A 67-year-old female was diagnosed with squamous cell carcinoma of the left tongue margin(cT2N0M0, Stage Ⅱ). The patient underwent tracheostomy, supraomohyoid neck dissection, hemiglossectomy, and reconstruction using a free forearm flap under general anesthesia. Venous congestion in the forearm flap was detected 21 hours postoperatively, and reanastomosis of the flap was performed. However, venous congestion continued after revision surgery. Therefore, we introduced medical leech therapy to treat the venous congestion. Leeches were used twice daily for 5 days, and the total hematophagy volume was 21.6 g. After leech treatment, continuous bleeding from the skin flap decreased and skin color improved. The medial skin flap survived, and the patient was able to eat 13 days after the initial operation. The rest of the treatment has been uneventful to date without dysfunction of the skin flap.

[A Contrivance for Closure and Dressing of Orocutaneous Fistula Developed in Advanced Oral Cancer]

Orocutaneous fistula sometimes occurs in locallyadvanced unresectable or recurrent oral squamous cell carcinoma. The developed orocutaneous fistula results in constant leakage of saliva, ingested foods and liquids and decline in patients' quality of life(QOL). A 47-year-old Japanese man had received treatment for tongue carcinoma. At the routine follow-up, a cystic lesion in the right submandibular region was detected. Biopsyof the specimen of the cystic lesion revealed squamous cell carcinoma. After chemotherapy, an orocutaneous fistula between the right oropharyngeal and the right submandibular region developed and graduallyincreased. Although closure and dressing of the orocutaneous fistula with various materials was attempted, it was ultimatelyunsuccessful. Finally, application of a rubber film and silicone adhesive agent to the skin was successful for closure and dressing of the fistula. Orocutaneous fistula is one of major contributors to decline in patients' QOL. The sharing of information regarding effective methods or materials for closure and dressing of orocutaneous fistula is necessaryto maintain patients' QOL.

Anomalous vortex motion in the quantum-liquid phase of amorphous MoxSi1-x films

We measure, in real time (t), the fluctuating component of the flux-flow voltage V(t), deltaV(t) identical withV(t)-V0, about the average V0 in the vortex-liquid phase of amorphous MoxSi1-x films. For the thick film, deltaV(t) originating from the vortex motion is clearly visible in the quantum-liquid phase, where the distribution of deltaV(t) is asymmetric, indicative of large velocity and/or number fluctuations of driven vortices. For the thin film the similar anomalous vortex motion is observed in nearly the same (reduced-)temperature regime. These results suggest that vortex dynamics in the low-temperature liquid phase of thick and thin films is dominated by common physical mechanisms, presumably related to quantum effects.

Enhancement of the quantum-liquid phase by increased resistivity in thick a-MoxSi1-x films

Effects of normal-state resistivity rho(n) on the vortex phase diagram at low temperature T have been studied based on dc and ac complex resistivities for thick amorphous MoxSi(1-x) films. It is commonly observed irrespective of rho(n) that, in the limit T=0, the vortex-glass-transition line B(g)(T) is independent of T and extrapolates to a field below the T=0 upper critical field B(c2)(0), indicative of the quantum-vortex-liquid (QVL) phase in the regime B(g)(0)<B<B(c2)(0). The relative width of the QVL phase increases along the B and T axes approximately proportional to rho(n). This result is consistent with a view that the QVL phase is caused by strong quantum fluctuations, which are enhanced with increasing rho(n).

Vortex glass transition and quantum vortex liquid at low temperature in a thick a- MoxSi1-x film

We present measurements of ac complex resistivity, as well as dc resistivity, for a thick amorphous MoxSi1-x film at low temperatures ( T>0.04 K) in various constant fields B. We find that the vortex glass transition (VGT) persists down to T approximately 0.04Tc0 up to B approximately 0.9Bc2(0), where Tc0 and Bc2(0) are the mean-field transition temperature and upper critical field at T = 0, respectively. In the limit T-->0, the VGT line Bg(T) extrapolates to a field below Bc2(0), while the dc resistivity rho(T) tends to the finite nonzero value in fields just above Bg(0). These results indicate the presence of a metallic quantum vortex liquid at T = 0 in the regime Bg(0)<B<Bc2(0).

Irsogladine maleate may preserve gastric mucosal hydrophobicity against ethanol in phospholipids independent way in rats

Irsogladine maleate (IM) has been used as a mucosal protective agent, whose action is partially explained as enhancement of mucosal blood flow, increase of cellular cyclic AMP and facilitation of gap-junctional intercellular communication. Effect of IM on rat gastric mucosal hydrophobicity, one of the mucosal barrier properties, was investigated, in comparison with that of 16,16-dimethyl prostaglandin E2 (dmPGE2). IM alone had no effect on mucosal hydrophobicity and mucosal phospholipids content. dmPGE2 alone did not change mucosal hydrophobicity significantly, but remarkably increased mucosal surface-active phospholipids. Intragastric administration of absolute ethanol significantly decreased gastric mucosal hydrophobicity and mucosal phospholipids content. IM could prevent the decrease in mucosal hydrophobicity by ethanol, maintaining the surface mucus gel layer and mucosal surface phospholipids almost as non-damaged control levels, whereas dmPGE2 also prevented the decrease in mucosal hydrophobicity by ethanol, with the surface epithelium being partially exfoliated and mucosal surface-active phospholipids showing remarkable enhancement. These results suggest that IM may preserve gastric mucosal hydrophobicity against ethanol, not through enhancement of mucosal phospholipids content like prostaglandin, but possibly through its reported stabilization action to the epithelial cell lining, which may preserve the surface epithelium with the mucous gel layer containing surface-active phospholipids, a possible origin of mucosal hydrophobicity.

[Sarcomatous malignant mesothelioma diagnosed after death]

A 77-year-old man with diabetes mellitus who was being treated as an outpatient had abnormal shadow in the right lower lobe on a chest roentgenogram in June 1993. In July 1994, a productive cough developed, and subsequent dyspnea obliged him to enter our hospital. Retention of pleural fluid led us to suspect tuberculosis pleurisy and to perform a pleural biopsy and a thoracentesis to remove pleural fluid but no final diagnosis was reached. About 14 months later he died of dyspnea with a rapidly growing tumor. An autopsy disclosed a giant tumor that occupied the right pleural cavity, excluding the lung. The tumor was well-defined between the lung and had infiltrated into the mediastinum. The histopathological diagnosis was primary malignant mesothelioma, sarcomatous type, of the visceral pleura.

The cell population of somatostatin and growth hormone-releasing factor using quantitative immunohistochemistry in the isolated GH deficient dwarf rat

We examined the cell population of somatostatin (SS) in the periventricular nucleus (PN) and growth hormone-releasing factor (GRF) in the arcuate nucleus (ARC) between spontaneous dwarf rats (SDRs; gene symbol: dr), which show isolated GH deficiency, and normal rats using avidin-biotin complex (ABC) immunohistochemistry. The total number of SS perikarya per brain weight in the PN of SDRs was 824.8 +/- 49.6 (mean +/- S.E.M., n = 4), whereas that of controls was 1108.5 +/- 50.1 (n = 4). The GRF perikarya per brain weight in the ARC of SDRs numbered 1281.0 +/- 26.0 (n = 7), as compared to 685.4 +/- 64.6 (n = 7) in the controls. The SS perikarya in the PN of SDRs were significantly reduced (P less than 0.05), while the GRF perikarya in the SDRs were significantly increased (P less than 0.01). These results suggest that GH itself acts on SS to positively regulate its secretion and on GRF in a negative regulatory manner.

Molecular mechanism of growth hormone (GH) deficiency in the spontaneous dwarf rat: detection of abnormal splicing of GH messenger ribonucleic acid by the polymerase chain reaction

The spontaneous dwarf rat (SDR) is an experimental model for pituitary dwarfism with an autosomal recessive mode of inheritance. In the pituitary of the SDR, neither GH cells nor GH protein were detected by immunological methods, but SDR pituitary has a very small amount of GH mRNA. In the present study the effects of GH-releasing factor and an analog of its second messenger, (Bu)2cAMP, on the total accumulation and secretion of GH were studied in primary cultures from SDR pituitaries. GH-releasing factor and (Bu)2cAMP increased the amount of GH mRNA, but neither accumulation nor secretion of immunoreactive GH was detected. These results suggested that the mutation is not manifest during transcription, but at a later stage. The GH gene of SDR was cloned, and its sequence was determined. A point substitution was found in the consensus sequence of the 3' splice site of the third intron. Judging from this point mutation, one would predict an abnormal splicing and a 1-base deletion in the GH mRNA. Therefore, the fragment of SDR GH cDNA in which the deletion was predicted was amplified by the polymerase chain reaction. Its sequence analysis confirmed that the SDR GH mRNA had 1 base deletion which must cause a premature translational termination of GH mRNA. These results demonstrate that GH deficiency in SDR is caused by a point mutation in the GH gene producing an abnormal splicing of GH mRNA.

Studies on prolactin and growth hormone gene expression in the pituitary gland of spontaneous dwarf rats

The spontaneous dwarf rat (SDR) is a newly established experimental model for pituitary dwarfism with an autosomal recessive mode of inheritance. GH and PRL gene expressions were studied in the pituitary gland of this animal. Immunocytochemistry failed to detect any immunoreactive GH cells in SDR pituitary gland, whereas numerous PRL cells were encountered throughout the anterior lobe. Similarly, GH was not detectable in the pituitary cytosol from SDR of 7, 20, and 80 days of age. PRL of the same mol wt as the authentic rat PRL was found in the pituitary glands in all SDRs examined. Since these results were thought to be due to the absence of GH mRNA in the SDR's pituitary gland, we attempted to detect GH mRNA by dot hybridization. Very small amounts of GH mRNA were found in the pituitary glands of both male (2.6% of normal) and female (6.0% of normal) SDRs. Reduced levels of PRL mRNA were also found in the pituitary glands of male (50%) and female (30%) SDRs. Northern blot analyses of total RNA extracts revealed that the GH mRNA of the SDR was similar in size to the mature GH mRNA found in the pituitary glands of control rats. PRL mRNA from the SDR also migrated to the same position as normal PRL mRNA. Nuclear DNA preparations were prepared from normal and SDR livers, and the genomic organizations of the GH and PRL genes were examined using restriction mapping. The DNA fragment length patterns obtained with the cDNA probes for GH or PRL using several restriction enzyme digestions were identical. The results suggest that the GH deficiency in SDR is not due to a gross deletion or rearrangement of the GH gene. It is proposed that SDR may be an excellent experimental model for the study of isolated GH deficiency in the human.