A Case of Refractory Tracheocutaneous Fistula Successfully Treated With the Combination of Auricular Cartilage Grafting and Sternocleidomastoid Muscle Flap.

The tracheotomy site usually closes spontaneously after decannulation, but in rare cases, it develops into tracheocutaneous fistula. We experienced a case of tracheocutaneous fistula that was successfully treated with the combination of auricular cartilage grafting and sternocleidomastoid muscle flap. In this case, we performed the closure of tracheocutaneous fistula with a view to filling the tissue defect with soft tissue to prevent recurrence. The surgical procedure performed in this case was unique, which to our knowledge, has not been described previously. Herein, we report some findings obtained, together with a literature review. The patient was a 73-year-old male. Starting five months after tracheotomy, the closure of a tracheocutaneous fistula was attempted twice at an otolaryngology clinic, which resulted in recurrence. The patient visited our department with the desire to close the tracheocutaneous fistula. At the initial examination, we found a cutaneous fistula with a diameter of approximately 2 mm on the cranial side of the sternal notch and thinning of the surrounding tissue. Preoperative computed tomography (CT) showed a tracheal defect with a size of approximately 10 mm on the caudal side of the sternal notch. The surgery was performed under general anesthesia 10 months after tracheotomy. The platysma muscle was attached to elevate the skin flap, and the scarring at the cutaneous fistula opening was removed. The cartilage defect was 10×12 mm in size. A piece of cartilage was harvested from the posterior surface of the auricle (navicular fossa) and grafted to the tracheal opening. A part of the left sternocleidomastoid muscle body of the sternal head was dissected from the mandibular side using the sternal attachment site as a stalk and elevated. The muscle flap was rotated, with its tip folded back, doubled over, and fixed on top of the auricular cartilage graft. The platysma muscles were sutured together during which the skin flap suture line was shifted so that the suture line would not coincide with the tracheal fistula site. The course was favorable, with no recurrence for three years. In the closure of a tracheocutaneous fistula, two sides need to be considered: the trachea and the skin. The tracheal defect in the present case was larger than 10 mm in size and thus auricular cartilage grafting was performed. In addition, we filled the tissue defect with the soft tissue of a sternocleidomastoid muscle flap, which was a unique step. The combined use of auricular cartilage grafting and sternocleidomastoid muscle flap was effective for the closure of a refractory tracheocutaneous fistula.

Efficacy of Keratin AE1/AE3 Staining in Evaluating Resection Margins of a Urachal Remnant and Improving Surgical Precision and Outcomes: A Case Report.

A urachal remnant is a rare condition characterized by the persistence of the urachus beyond birth, often presenting with symptoms such as umbilical effusion, periomphalitis, and abdominal pain. Surgical resection is the cornerstone of treatment, but ensuring complete removal of urachal epithelium at the resection margin remains a challenge. This case report focuses on evaluating resection margins of urachal remnants and reports the case of a 25-year-old woman with complaints of umbilical effusion and a mass. She was diagnosed with a urachal remnant and underwent urachal resection and reconstruction, with postoperative confirmation of favorable outcomes and the absence of microscopic hematuria. The intraoperative examination did not reveal any macroscopically clear luminal structure of the urachal resection margin. Subsequent histopathological analysis of the margin using hematoxylin and eosin staining was challenging, prompting the use of immunohistological staining with keratin AE1/AE3 antibody. The antibody did not stain the urachal resection margin, confirming the complete removal of urachal epithelial components. Our study findings suggest the utility of keratin AE1/AE3 staining for assessing urachal remnant margins and underscore the importance of thorough evaluation and complete resection of urachal remnant to prevent recurrence and mitigate the risk of urachal cancer, contributing to improved surgical outcomes and patient care.

[Current Status of Calculation of Continence Care Fee for Out-Patients at Kurosawa Hospital].

The continence self-management programme fee (CSPF) for hospitalized patients was revised in 2020 to include those receiving consistent care on an out-patient basis. We extracted candidate patients for CSPF on an out-patient basis (out-patient candidates hereafter) from those for whom-CSPF had been calculated during hospitalization at our hospital, and defined those who had undergone a medical examination related to continence care as out-patient calculation candidates. Of the 956 patients for whom CSPF had been calculated during hospitalization, 482 patients (50%) were out-patient candidates ; 275 (54%) and 169 (33%) of whom were seen in the urology and neurosurgery departments, respectively. Of the 482 out-patient candidates, 238 (49%) were out-patient calculation candidates ; 197 (83%) and 14 (6%) of whom were seen in the urology and neurosurgery departments, respectively. Forty-two and 41 of the calculation candidates were cases of benign prostatic hyperplasia and bladder cancer, respectively. The CSPF was actually processed 93 times for 78 of the 482 out-patient candidates (16%). There were various obstacles in the current system of calculating the fees to realize consistent care from hospitalization to out-patient care.

A Histological Evaluation of Artificial Dermal Scaffold Used in Micrograft Treatment: A Case Study of Micrograft and NPWT Performed on a Postoperative Ulcer Formation after Tumor Resection.

Background and Objectives: Wound healing (WH) is a complex natural process: the achieving of a proper WH with standard therapies sometimes is not fulfilled and it is often observed in aged and diabetic patients, leading to intractable ulcers. In recent years, autologous micrograft (AMG) therapies have become a new, effective, and affordable wound care strategy among both researchers and clinicians. In this study, a 72-year-old female patient underwent a combination of treatments using micrograft and negative pressure wound therapy (NPWT) on a postoperative skin ulcer after a benign tumor resection on the back with the aim to present an innovative method to treat skin ulceration using AMG combined with an artificial dermal scaffold and NPWT. Materials and Methods: A section of the artificial dermal scaffold, infused with micrografts, was sampled prior to transplant, and sections were collected postoperatively on days 3 and 7. Hematoxylin-eosin (HE) and immunohistochemical stains were employed for the evaluation of Cytokeratin AE1/AE3, desmin, and Factor VIII. Additionally, on postoperative day 3, NPWT dressing was evaluated using HE stains, as well. The resulting HE and immunostaining analysis revealed red blood cells and tissue fragments within the collagen layers of the artificial dermis prior to transplant. On postoperative day 3, collagen layers of the artificial dermis revealed red blood cells and neutrophils based on HE stains, and scattering of cytokeratin AE1/AE3-positive cells were detected by immunostaining. The HE stains on postoperative day 7 showed more red blood cells and neutrophils within the collagen layers of the artificial dermis than on day 3, an increase in cytokeratin AE1/AE3-positive cells, and tissue stained positively with desmin and Factor VIII. Results: Results suggest that the effects of both micrografts and migratory cells have likely accelerated the wound healing process. Furthermore, the NPWT dressing on day 3 showed almost no cells within the dressing. This indicated that restarting NPWT therapy immediately after micrograft transplant did not draw out cells within the scaffold. Conclusions: Micrograft treatment and NPWT may serve to be a useful combination therapy for complex processes of wound healing.

Differentiation and proliferation potencies of human bone tissue-derived mesenchymal stromal cells (hBT-MSCs) after long-term cryopreservation －Comparison among cells stored for 1, 5, 10, 15, and 20 years.

INTRODUCTION: We investigated bone differentiation and proliferation potencies of human bone tissue-derived mesenchymal stromal cells (hBT-MSCs) after long-term cryopreservation. We determined the presence of any morphological and characteristic changes due to freezing to identify issues that need to be solved for future clinical applications. SUBJECTS AND METHODS: A total of 15 samples of hBT-MSCs that had been cryopreserved for different lengths of time, ranging from one year to 20 years (n = 3 each), were thawed and recultivated after being collected from excess iliac cancellous bone specimens of patients who underwent secondary alveolar bone grafting for cleft lip and palate in our department. We determined viability by observing calcein/EthD-stained cells under a confocal microscope, and the cell proliferation experiment was performed for one week using the Water Soluble Tetrazolium salts (WST) assay method. A confocal microscope was also used to identify any excessively accumulated senescence-associated growth factor SA-ßgal. Differentiation potency was assessed in the following three groups: bone differentiation, adipocyte differentiation, and nondifferentiation induction. We examined bone/adipocyte differentiation potencies using Alizarin Red staining, Ca quantitation, and Oil Red staining after continuously culturing cells for four weeks. RESULTS: Viability test results indicated that the proportion of viable cells decreased as the number of years of cryopreservation increased. The cell proliferation experiment showed that cells cryopreserved for a shorter duration multiplied exponentially. In the aging test, cells cryopreserved for ≥5 years showed similar positive reactions independent of the number of years of cryopreservation. In the cell proliferation test, there was no statistically significant difference between the years of cryopreserving. We compared bone differentiation and adipocyte differentiation ability with the non-induction group, and the induction group was confirmed to have a statistical advantage. However, there was no significant difference in the induction group pertaining to different ages. CONCLUSIONS: Samples cryopreserved for 20 years remained competent in bone and adipocyte differentiation. However, their differentiation direction tended to skew to either bone or adipocyte differentiation. Our results suggest that freezing does not accelerate aging, and samples cryopreserved for a long time are useful in future clinical applications.

A patient with macrodystrophia lipomatosa bilaterally affecting the entire upper extremity: reporting of a rare case and literature review.

The patient, a 58-year-old Asian female, had the progressive, bilateral overgrowth of the entire upper extremity since her childhood and has undergone debulking surgery twice in her country. However, overgrowth progressed after surgery. The patient was diagnosed with Macrodystrophia lipomatosa (MDL) by physical and imaging findings in our departments.

An in vitro long-term study of cryopreserved umbilical cord blood-derived platelet-rich plasma containing growth factors-PDGF-BB, TGF-ß, and VEGF.

PURPOSE: Umbilical cord blood-derived platelet-rich plasma (UCB-PRP) containing growth factors has attracted attention as a biomaterial useful for regenerative medicine. The osteoblastic differentiation of umbilical cord-derived mesenchymal stromal cells (UC-MSCs) can be induced by UCB-PRP. MATERIALS AND METHODS: Nine samples of UC and UCB were used to conduct an in vitro study that determined the contents of three growth factors (i.e., platelet-derived growth factor, transforming growth factor ß-1, and vascular endothelial growth factor) and that examined, by staining with Alizarin red, their ability to induce the osteoblastic differentiation of UC-MSCs at the baseline, 3 months, and 3 years of cryopreservation. RESULTS: The contents of growth factors in cryopreserved UCB-PRP were markedly elevated compared to those found in UCB at baseline. The samples of UCB that were added with cryopreserved UCB-PRP and those with bone morphogenetic protein-2 were stained granularly with Alizarin red, thus indicating the presence of calcium. The samples of UCB that were not added with UCB-PRP were not stained with Alizarin red. The above-mentioned contents and ability were maintained at 3 years of cryopreservation. Cryopreserved UCB-PRP possibly and advantageously induced the osteoblastic differentiation of UC-MSCs. CONCLUSION: The potential clinical application of cryopreserved UCB-PRP to regenerative medicine was suggested.

Assessment of antimicrobiral prophylaxis in transperineal prostate biopsy: A single-center retrospective study of 485 cases.

To verify the validity of our antimicrobial prophylaxis regimen for transperineal prostate biopsies, we investigated the rate of infectious complications in this procedure. We retrospectively investigated the infectious complications in 485 patients who underwent a transperineal prostate biopsy between 2014 and 2016 at our hospital. In the clinic, we use cefazolin (CEZ) for antimicrobial prophylaxis. Infectious complications were assessed up to postoperative day (POD) 30. Patients with infectious complications were further investigated to determine the site of infection, outbreak day, and type of pathogenic bacteria. The rate of infectious complications was 0.82% (4 out of 485 patients). Three patients developed prostatitis, 1 progressed into septic shock, and 1 patient developed epididymitis. The pathogenic bacteria identified were Pseudomonas aeruginosa (1 of 4), Enterococcus faecalis (1 of 4) and Escherichia coli that harbour extended-spectrum beta lactamase (ESBL-productive E. coli) (2 of 4). The earliest outbreak was POD 2 and the latest was POD 14. Infectious complications tended to increase in patients in whom an indwelling urethral catheter was inserted (p = 0.0567). However, there were no statistically significant relationships between any risk factor and the occurrence of infectious complications. We concluded that CEZ is adequate for the prevention of perioperative infectious complications in transperineal prostate biopsies. Furthermore, we reaffirmed the importance of correct perioperative management, including preoperative assessment.

[A CASE OF URETERAL ENDOMETRIOSIS].

A 49-year-old woman was admitted to our hospital due to macroscopic hematuria. Contrast-enhanced computed tomography revealed left hydronephrosis, a tumor at her left ureter, pseudoaneurysm and ovarian cystoma. Prior to the operation, the tumorous lesion was considered as left ureteral cancer without metastasis (cT4N0M0; stage IV). Left nephroureterectomy was performed. After the surgery, pathological examination revealed that this lesion was extrinsic endometriosis originating from the ureter.We here report this case of ureteral endometriosis that presented with atypical clinical findings along with a review of the literature.

A CASE OF GROWING TERATOMA SYNDROME.

A 25-year-old man with a left testicular tumor underwent a high inguinal orchiectomy. Histopathological examination of the resected specimen revealed tumors of more than one histological type, mixed forms (seminoma, immature teratoma). Further evaluation revealed no metastasis (pT1N0M0S1 Stage IS).Four months after orchiectomy, alpha-fetoprotein (AFP) was elevated.CT scan revealed retroperitoneal masses of recurrent tumor. Although the AFP returned to normal level after four courses of BEP (bleomycin, etoposide and cisplatin), the retroperitoneal lymph nodes continued to grow. He underwent excision of the retroperitoneal lymph node dissection. Histopathological examination of the resected specimen revealed mature teratoma.Few reports examined about the development mechanism of growing teratoma syndrome (GTS). We considered that the development mechanism of GTS in this case is induction of differentiation. In this case report, we discuss the development mechanism of GTS based on bibliographical consideration.

[SQUAMOUS CELL CARCINOMA WITH CLOACAL EXSTROPHY: A CASE REPORT].

A 41-year-old man with a history of cloacal exstrophy presented to a local clinic with abdominal pain and bowel sounds. He was noted to have pain at the site of scarring due to cloacal exstrophy and a laceration at its center, which was stained with feces. He was referred to our department because of an enterocutaneous fistula. Skin biopsy of the neoplastic lesion at this site led to a diagnosis of squamous cell carcinoma. Computed tomography showed tumor invasion of the ileum and right inguinal lymph node enlargement. We performed tumor resection, partial enterectomy, intestinal anastomosis, abdominal wall reconstruction with a left pedicled anterolateral thigh flap, split-thickness skin grafting, and right inguinal lymph node biopsy. Histopathological examination revealed cancer growth, invasion, and pearl formation in the lymph nodes, leading to a diagnosis of abdominal squamous cell carcinoma with metastasis to the inguinal lymph nodes. The skin graft took well, and the patient was discharged. He is scheduled for right inguinal lymph node dissection at a later date.

Osteogenic potential of human umbilical cord-derived mesenchymal stromal cells cultured with umbilical cord blood-derived fibrin: a preliminary study.

This study examined the potential for osteogenesis via regenerative medicine using autologous tissues (umbilical cord (UC) and umbilical cord blood (UCB)) in nude mice. The study was designed to provide the three elements required for regenerative medicine (cell, scaffold, and growth factor) and autoserum for culture by means of autologous tissues. Mesenchymal stromal cells were obtained from UC (UC-MSCs). Fibrin, platelet-rich-plasma, and autoserum were obtained from UCB as scaffold, growth factor and serum for culture respectively. UC-MSCs were obtained from Wharton jelly and cultured with UCB-derived fibrin (UCB-fibrin) for 3-4 weeks to induce their differentiation into osteoblasts. They were implanted subcutaneously into the dorsum of male nude mice for 6 weeks prior to undergoing assessment. The assessments performed were haematoxylin and eosin, and alizarin red staining, immunohistochemical staining of human mitochondria, scanning electron microscopy, scanning electron microscopy with energy dispersive X-ray spectrometry and real-time reverse transcriptase-polymerase chain reaction to assess the expressions of osteoblast markers. Consequently, the differentiation of UC-MSCs into osteoblasts and the production of hydroxyapatite were verified. This study suggested the possible formation of bone tissue using biomedical materials obtained from UC and UCB.

Osteogenic potential of human bone marrow-derived mesenchymal stromal cells cultured in autologous serum: a preliminary study.

PURPOSE: As part of the authors' research on potential osteogenesis by filling bone defects with human bone marrow-derived mesenchymal stromal cells (hBM-MSCs) in patients with cleft lip and palate, they examined the cytoproliferative potential and cytobiological activity of hBM-MSCs in vitro and their osteogenic potential in vivo without performing osteoinduction. MATERIALS AND METHODS: The hBM-MSCs were collected from iliac cancellous bone and then used in primary culture, followed by 2 subcultures using an autologous serum (AS)-containing medium and a fetal bovine serum (FBS)-containing medium. Cytoproliferative potential and cytobiological activity as expressed by bone markers (alkaline phosphatase and osteocalcin) in hBM-MSCs cultured in the AS-containing medium (AS-cultured hBM-MSCs) and the FBS-containing medium (FBS-cultured hBM-MSCs) were examined in vitro, and the osteogenic potential of AS- and FBS-cultured hBM-MSCs was examined in mice. RESULTS: On day 6 of the second subculture, the number of hBM-MSCs per milliliter of specimen from 8 pediatric patients was significantly larger (P < .05) in FBS-cultured compared with AS-cultured hBM-MSCs. The alkaline phosphatase activity of hBM-MSCs was significantly greater (P < .05) when cultured in the AS-containing medium compared with the FBS-containing medium. The in vivo study showed the formation of an osteoid-like matrix rather than definite bone tissue. CONCLUSIONS: 1) FBS is appropriate for the cytoproliferation of hBM-MSCs; 2) the AS-containing medium is likely to have a good possibility of inducing the differentiation of hBM-MSCs; and 3) AS-cultured hBM-MSCs contain a group of cells that spontaneously differentiate into an osteoid-like matrix without performing osteoinduction.

What factors are associated with good performance in children with cochlear implants? From the outcome of various language development tests, research on sensory and communicative disorders project in Japan: nagasaki experience.

OBJECTIVES: We conducted multi-directional language development tests as a part of the Research on Sensory and Communicative Disorders (RSVD) in Japan. This report discusses findings as well as factors that led to better results in children with severe-profound hearing loss. METHODS: We evaluated multiple language development tests in 33 Japanese children with cochlear implants (32 patients) and hearing aid (1 patient), including 1) Test for question and answer interaction development, 2) Word fluency test, 3) Japanese version of the Peabody picture vocabulary test-revised, 4) The standardized comprehension test of abstract words, 5) The screening test of reading and writing for Japanese primary school children, 6) The syntactic processing test of aphasia, 7) Criterion-referenced testing (CRT) for Japanese language and mathematics, 8) Pervasive development disorders ASJ rating scales, and 9) Raven's colored progressive matrices. Furthermore, we investigated the factors believed to account for the better performances in these tests. The first group, group A, consisted of 14 children with higher scores in all tests than the national average for children with hearing difficulty. The second group, group B, included 19 children that scored below the national average in any of the tests. RESULTS: Overall, the results show that 76.2% of the scores obtained by the children in these tests exceeded the national average scores of children with hearing difficulty. The children who finished above average on all tests had undergone a longer period of regular habilitation in our rehabilitation center, had their implants earlier in life, were exposed to more auditory verbal/oral communication in their education at affiliated institutions, and were more likely to have been integrated in a regular kindergarten before moving on to elementary school. CONCLUSION: In this study, we suggest that taking the above four factors into consideration will have an affect on the language development of children with severe-profound hearing loss.

Bilateral cochlear implantation for children in nagasaki, Japan.

OBJECTIVES: The number of patients with bilateral cochlear implant (CI) has gradually increased as patients and/or parents recognize its effectiveness. The purpose of this report is to evaluate the efficacy of 29 bilateral CI out of 169 pediatric CI users, who received auditory-verbal/oral habilitation at our hearing center. METHODS: We evaluated the audiological abilities 29 Japanese children with bilateral CIs including wearing threshold, word recognition score, speech discrimination score at 1 m from front speaker (SP), 1 m from second CI side SP, speech discrimination score under the noise (S/N ratio=80 dB sound pressure level [SPL]/70 dB SPL, 10 dB) at 1 m from front SP, word recognition score under the noise (S/N ratio=80 dB SPL/70 dB SPL, 10 dB) at 1 m from front SP. RESULTS: Binaural hearing using bilateral CI is better than first CI in all speech understanding tests. Especially, there were significant differences between the results of first CI and bilateral CI on SDS at 70 dB SPL (P=0.02), SDS at 1 m from second CI side SP at 60 dB SPL (P=0.02), word recognition score (WRS) at 1 m from second CI side SP at 60 dB SPL (P=0.02), speech discrimination score (SDS) at 1 m from front SP under the noise (S/N=80/70; P=0.01) and WRS at 1 m from front SP under the noise (S/N=80/70; P=0.002). At every age, a second CI is very effective. However, the results of under 9 years old were better than of over 9 years old on the mean SDS under the noise (S/N=80/70) on second CI (P=0.04). About use of a hearing aid (HA) in their opposite side of first CI, on the WRS and SDS under the noise, there were significant differences between the group of over 3 years and the group of under 10 months of HA non user before second CI. CONCLUSION: These results may show important binaural effectiveness such as binaural summation and head shadow effect. Bilateral CI is very useful medical intervention for many children with severe-to-profound hearing loss in Japan as well as elsewhere.

Osteogenic potential of human umbilical cord-derived mesenchymal stromal cells cultured with umbilical cord blood-derived autoserum.

OBJECTIVE: Osteogenesis in the bone defect at the site of an alveolar cleft is important to enable patients with cleft lip and palate to acquire dental articulation. The presence of umbilical cord-derived mesenchymal stem cells has been reported. In this study, we used autoserum derived from the umbilical cord blood (UCB) of neonates in an attempt to examine the osteoblastic differentiation potential of umbilical cord-derived mesenchymal stromal cells (UC-MSCs) in nude mice. MATERIALS AND METHODS: UCB, hydroxyapatite, and rhBMP were used as the supply source of autoserum, scaffold, and osteoinductive growth factor, respectively. MSCs, obtained from Wharton's jelly and cultured for 3-4weeks to induce their differentiation into osteoblasts, were implanted subcutaneously into the dorsum of male nude mice for 6weeks before the assessment by real-time reverse transcriptase chain reaction of osteoblast marker expression. RESULTS: UCB-derived autoserum was a viable source for the culture and implantation of UC-MSCs. The osteoblastic differentiation potential of UC-MSCs was demonstrated in nude mice by performing immunohistochemical staining and by the presence of osteoblast marker expression. CONCLUSIONS: Our results confirm the osteogenic potential of UC-MSCs and provide basic evidence for the realization of regenerative medicine using autologous tissues.

Activity-dormancy transition in the cambial meristem involves stage-specific modulation of auxin response in hybrid aspen.

The molecular basis of short-day-induced growth cessation and dormancy in the meristems of perennial plants (e.g., forest trees growing in temperate and high-latitude regions) is poorly understood. Using global transcript profiling, we show distinct stage-specific alterations in auxin responsiveness of the transcriptome in the stem tissues during short-day-induced growth cessation and both the transition to and establishment of dormancy in the cambial meristem of hybrid aspen trees. This stage-specific modulation of auxin signaling appears to be controlled via distinct mechanisms. Whereas the induction of growth cessation in the cambium could involve induction of repressor auxin response factors (ARFs) and down-regulation of activator ARFs, dormancy is associated with perturbation of the activity of the SKP-Cullin-F-box(TIR) (SCF(TIR)) complex, leading to potential stabilization of repressor auxin (AUX)/indole-3-acetic acid (IAA) proteins. Although the role of hormones, such as abscisic acid (ABA) and gibberellic acid (GA), in growth cessation and dormancy is well established, our data now implicate auxin in this process. Importantly, in contrast to most developmental processes in which regulation by auxin involves changes in cellular auxin contents, day-length-regulated induction of cambial growth cessation and dormancy involves changes in auxin responses rather than auxin content.

Purification and identification of a novel primitive secretory enzyme catalyzing the hydrolysis of imidazole-related dipeptides in the jawless vertebrate Lethenteron reissneri.

Imidazole-related dipeptides, such as carnosine and anserine, occur widely in skeletal muscles of jawed vertebrates. All of the known enzymes that catalyze the hydrolysis of these dipeptides belong to the M20A metallopeptidase subfamily; two secretory enzymes, serum carnosinase (EC 3.4.13.20) and anserinase (EC 3.4.13.5), and one non-secretory enzyme, cytosolic nonspecific dipeptidase (EC 3.4.13.18). Here we report the enzymatic characterization and molecular identification of an unidentified enzyme, which catalyzes the hydrolysis of these dipeptides, from the skeletal muscle of Far Eastern brook lamprey (Lethenteron reissneri). A 60-kDa subunit protein of the enzyme was purified to near homogeneity. We cloned two M20A genes from the skeletal muscle of Far Eastern brook lamprey; one was a secretory-type gene encoding for the 60-kD protein, and another was a non-secretory-type gene presumably encoding for cytosolic nonspecific dipeptidase. Our findings indicate that the purified enzyme is a N-glycosylated secretory M20A dipeptidase distributed specifically in the jawless vertebrate group, and may be derived from a common ancestor gene between serum carnosinase and anserinase. We propose that this dipeptidase is a novel secretory M20A enzyme and is classified as neither serum carnosinase nor anserinase.