[Analysis of the Factors in Successful Helmet Non-invasive Positive Pressure Ventilation].

BACKGROUND: Non-invasive positive pressure ventilation (NPPV) reduces the incidences of ventilator-associated pneumonia, the duration of ICU stay and the mortality rate compared with conventional respiratory management of the patients with acute respiratory failure (ARF). Recently, helmet NPPV equipment became available. Because of the high tolerability, the helmet seems to be the best NPPV interface when prolonged and continuous assistance is needed. In this study, we analyzed several factors related to failure of helmet NPPV in ARF patients in intensive care unit (ICU), retrospectively. METHODS: Institutional Research Committee of Nagasaki Rosai Hospital approved this study. We studied consecutive patients with ARF who needed ventilator support in ICU from February 2012 to February 2013. We excluded the patients whose trachea had been intubated before admission to ICU and comatose patients. After admission to ICU, all ARF-patients received helmet NPPV and conventional intensive care therapy including sedation with dexmedetomidine and vasoactive agents. General clinical data including blood gas analysis were recorded at admission to ICU and during ICU stay. Patient's tracheas were intubated if they met at least one of the following criteria, as judged after they had received helmet NPPV: lack of improvement in arterial blood pH or PaCO2; changes in mental status, in patients unable to tolerate noninvasive ventilation; a decrease in SaO2 to less than 85% despite the use of a high FIO2. The final decision of endotracheal intubation was made by a staff intensivist. We defined the failure of helmet NPPV as the execution of endotracheal intubation. The data were presented as median (IQR), and statistical analysis was performed using Mann-Whitney U-test and Fisher's exact probability test at the P<0.05 level of significance. RESULTS: The subjects were 36 patients (25 males and 11 females) aged 27 to 94 years, including 6 patients with acute heart failure (AHF), 8 with pneumonia, 6 with aspiration pneumonia, 2 with hemothorax, 10 with acute respiratory distress syndrome (ARDS), 1 with asthma, and 3 with acute exacerbation of chronic obstructive pulmonary disease (COPD). NPPV was successful in 29 (19 males and 10 females), but unsuccessful in 7 patients (6 males and 1 female). There were no significant differences in demographic data and the variables before induction of NPPV between the successful and unsuccessful groups. The P/F ratio was improved from 133 (99,167) to 209 (143,274) in the successful group, and from 93 (81,157) to 188 (129,271) in the unsuccessful group after the induction of NPPV, but there was no significant difference between the two groups. In the patients with unsuccessful NPPV, expiratory positive airway pressure, inspiratory positive airway pressure, respiratory rate, body temperature and FIO2 before removing NPPV were significantly higher, and ICU stay was longer compared with the patients with successful NPPV. Furthermore, marked excretion of sputum was observed in 4 of the 7 patients with unsuccessful NPPV. CONCLUSIONS: Helmet NPPV improved oxygenation in ARF patients immediately after induction of NPPV. Although there were no significant predictable parameters of unsuccessful NPPV before induction of NPPV, a lot of excretion of sputum might be suggested as a risk factor.

Differentiated melanocyte cell division occurs in vivo and is promoted by mutations in Mitf.

Coordination of cell proliferation and differentiation is crucial for tissue formation, repair and regeneration. Some tissues, such as skin and blood, depend on differentiation of a pluripotent stem cell population, whereas others depend on the division of differentiated cells. In development and in the hair follicle, pigmented melanocytes are derived from undifferentiated precursor cells or stem cells. However, differentiated melanocytes may also have proliferative capacity in animals, and the potential for differentiated melanocyte cell division in development and regeneration remains largely unexplored. Here, we use time-lapse imaging of the developing zebrafish to show that while most melanocytes arise from undifferentiated precursor cells, an unexpected subpopulation of differentiated melanocytes arises by cell division. Depletion of the overall melanocyte population triggers a regeneration phase in which differentiated melanocyte division is significantly enhanced, particularly in young differentiated melanocytes. Additionally, we find reduced levels of Mitf activity using an mitfa temperature-sensitive line results in a dramatic increase in differentiated melanocyte cell division. This supports models that in addition to promoting differentiation, Mitf also promotes withdrawal from the cell cycle. We suggest differentiated cell division is relevant to melanoma progression because the human melanoma mutation MITF(4T)(Δ)(2B) promotes increased and serial differentiated melanocyte division in zebrafish. These results reveal a novel pathway of differentiated melanocyte division in vivo, and that Mitf activity is essential for maintaining cell cycle arrest in differentiated melanocytes.

Open Abdominal Management for Damage Control in Liver Transplantation: A Single-center Experience.

Background: Patients undergoing liver transplantation are in a state of coagulopathy before surgery because of liver failure. Intraoperative hemorrhage, massive transfusions, and post-reperfusion syndrome further contribute to coagulopathy, acidosis, and hypothermia. In such situations, temporary cessation of surgery with open abdominal management and resuscitation in the intensive care unit (ICU), which is commonly used as a damage control strategy in trauma care, may be effective. We assessed the outcomes of open abdominal management in liver transplantation and the corresponding complication rates. Methods: We retrospectively reviewed the outcomes of patients undergoing open abdominal management among 250 consecutive liver transplantation cases performed at our institution from 2009 to 2022. Results: Open abdominal management was indicated in 16 patients. The open abdomen management group had higher Model for End-stage Liver Disease scores (24 versus 16, P < 0.01), a higher incidence of previous upper abdominal surgery (50% versus 18%, P < 0.01), more pretransplant ICU treatment (31% versus 10%, P = 0.03), and more renal replacement therapy (38% versus 12%, P = 0.01). At the time of the damage control decision, coagulopathy (81%), acidosis (38%), hypothermia (31%), and a high-dose noradrenaline requirement (75%) were observed. The abdominal wall was closed in the second operation in 75% of patients, in the third operation in 19%, and in the fourth operation in 6%. Postoperatively, the frequency of early allograft dysfunction was predominantly higher in the open abdominal management group (69%), whereas the frequency of vascular complications and intra-abdominal infection was the same as in other patients. Conclusions: Open abdominal management can be a crucial option in cases of complex liver transplant complicated by conditions such as hypothermia, acidosis, coagulopathy, and hemodynamic instability. Damage control management minimizes deterioration of the patient's condition during surgery, allowing completion of the planned procedure after stabilizing the patient's overall condition in the ICU.

Successful vaginal delivery in a parturient with long QT syndrome type 2 using double-catheter epidural analgesia: A CARE-compliant case report.

RATIONALE: Congenital long QT syndrome (LQTS) can cause syncope or sudden death due to ventricular arrhythmia. Congenital LQTS has 3 major types, 1, 2, and 3. Life-threatening arrhythmias are triggered by emotion in patients with LQTS type 2. As patients with LQTS type 2 have a higher incidence of postnatal cardiac events, careful perinatal management especially during delivery is required. To the best of our knowledge, perinatal management of a patient with LQTS type 2 has not been properly described with consideration to its type-specific risk factors for ventricular tachyarrhythmia. PATIENT CONCERNS: A 36-year-old pregnant woman, gravida 1, para 0, with LQTS type 2 was scheduled to undergo vaginal delivery under epidural labor analgesia in the 38th week of pregnancy. No fainting episodes were reported since she began to take 40 mg of propranolol once daily at the age of 25. Despite this, we instituted maximum preventive measures for the safety of both the parturient and the fetus to minimize the risk of maternal cardiac events throughout the perinatal period. DIAGNOSES: She was diagnosed with LQTS type 2 by genetic testing at the age of 25. INTERVENTIONS: Two epidural catheters were placed at levels T11-T12 and L5-S1. Injection of 0.2% ropivacaine and subsequent infusion of ropivacaine 0.1% with fentanyl (2 µg/mL) was directed through each catheter according to the stage of labor. Concurrently, landiolol, a selective and short-acting ß1 receptor antagonist, was infused intravenously at a dose of 1 to 7 µg/kg/min. OUTCOMES: The delivery proceeded uneventfully without pain. No adverse cardiac events were observed during the perinatal period. LESSONS: Vaginal delivery under epidural labor analgesia using 2 catheters might be a viable option for maternal perinatal care and delivery of patients with LQTS type 2.

Successful treatment of severe adrenaline-resistant anaphylactic shock with glucagon in a patient taking a beta-blocker: a case report.

BACKGROUND: The efficacy of glucagon for adrenaline-resistant anaphylactic shock in patients taking ß-blockers is controversial. However, understanding the efficacy of glucagon is important because adrenaline-resistant anaphylactic shock is fatal. We present a case of severe adrenaline-resistant anaphylactic shock in a patient taking a ß-blocker, and glucagon was effective in improving hemodynamics. CASE PRESENTATION: An 88-year-old woman with severe aortic stenosis and taking a selective ß-1 blocker underwent transcatheter aortic valve implantation under general anesthesia. Postoperatively, she received 100 mg sugammadex, but 2 min later developed severe hypotension and bronchospasm. Suspecting anaphylactic shock, we intervened by administering adrenaline, fluid loading, and an increased noradrenaline dose. Consequently, the bronchospasm improved, but her blood pressure only increased minimally. Therefore, we administered 1 mg glucagon intravenously, and the hypotension resolved immediately. CONCLUSIONS: Glucagon may improve hemodynamics in adrenaline-resistant anaphylactic shock patients taking ß-blockers; however, its efficacy must be further evaluated in more cases.

Anaphylactic shock in a patient with severe aortic stenosis treated with adrenaline and landiolol for circulatory management: A case report.

RATIONALE: We present the first case of a patient with severe aortic stenosis who developed anaphylactic shock and was successfully treated with adrenaline and landiolol, a highly selective ß1-receptor blocker, to prevent disruption of the myocardial oxygen supply-demand balance caused by tachycardia. PATIENT CONCERNS: An 86-year-old woman was scheduled for simultaneous anterior-posterior fixation for a burst fracture of the 12th thoracic vertebra; 200 mg sugammadex, a neuromuscular blocking agent antagonist, was administered postoperatively, and she was extubated without complications. However, 6 min after extubation, her blood pressure decreased abruptly to 55/29 mm Hg, and her heart rate increased to 78 bpm. Then, we intervened with fluid loading, an increased dose of noradrenaline, and phenylephrine administration. However, her blood pressure did not increase. DIAGNOSES: A general observation revealed urticaria on the lower leg; thus, we suspected anaphylactic shock due to sugammadex administration. INTERVENTIONS: We carefully administered 2 doses of 0.05 mg adrenaline and simultaneously administered landiolol at 60 µg/kg/min to suppress adrenaline-induced tachycardia. Adrenaline administration resulted in a rapid increase in blood pressure to 103/66 mm Hg and a maximum heart rate of 100 bpm, suppressing excessive tachycardia. OUTCOMES: The patient's general condition was stable after the intervention, and circulatory agonists could be discontinued the following day. She was discharged from the intensive care unit on the fourth postoperative day. LESSONS: Landiolol may help control the heart rate of patients with aortic stenosis and anaphylactic shock. The combined use of landiolol and adrenaline may improve patient outcomes; however, their efficacy and risks must be evaluated by studying additional cases.

Growth inhibitory effects of pegylated IFN-alpha2b and 5-fluorouracil in combination on renal cell carcinoma cell lines in vitro and in vivo.

We investigated the effects of pegylated IFN-alpha2b (PEG-IFN-alpha2b) alone and PEG-IFN-alpha2b plus 5-fluorouracil (5-FU) in vitro on the proliferation of renal cell carcinoma (RCC) cell lines. After the transplantation of RCC cells into nude mice, we administered IFN (PEG-IFN-alpha2b or IFN-alpha2b) alone, 5-FU alone, or IFN (PEG-IFN-alpha2b or IFN-alpha2b) plus 5-FU; and investigated tumor volume, tumor weight, the numbers of apoptotic cells and artery-like blood vessels, relative mRNA expression levels of enzymes which relate to 5-FU metabolism, angiogenesis factor, and type I interferon receptor. RCC cells in vitro were generally and relatively resistant to the anti-proliferative effects of PEG-IFN-alpha2b, but the addition of 5-FU augmented IFN-induced anti-proliferative effects with the induction of apoptosis. PEG-IFN-alpha2b in vivo presented stronger anti-tumor effects than IFN-alpha2b, and its combination with 5-FU augmented the effects. The significant anti-tumor effect of the combination treatment was the increase in apoptotic cell number, but there were no significant differences in the suppression of angiogenesis, expression of IFN receptor, and the actions of metabolic enzymes of 5-FU. In conclusion, PEG-IFN-alpha2b presents stronger anti-tumor effects than non-pegylated IFN, and the effects are augmented in the combination with 5-FU. Our findings suggest the clinical usefulness of PEG-IFN-alpha2b in the treatment of RCC.

Growth inhibitory effects of IFN-beta on human liver cancer cells in vitro and in vivo.

We investigated the effects of interferon-beta (IFN-beta) on the growth of human liver cancer cells. The effects of IFN-beta with or without 5-fluorouracil (5-FU) on the proliferation of 13 liver cancer cell lines were investigated in vitro. Chronologic change in IFN-alpha receptor 2 (IFNAR-2) expression was monitored in hepatocellular carcinoma (HCC) cells (HAK-1B) cultured with IFN-beta. After HAK-1B cells were transplanted into nude mice, various doses of IFN-beta were administered, and the tumor volume, weight, histology, tumor blood vessel, and angiogenesis factor expression were examined. IFN-beta inhibited the growth of 11 cell lines with apoptosis in a dose-dependent and time-dependent manner. With IFN-beta, IFNAR-2 expression in HAK-1B cells was significantly downregulated from 6 to 12 h. IFN-beta induced a dose-dependent decrease in tumor volume and weight and a significant increase of apoptosis in the tumor. Both basic fibroblast growth factor (bFGF) and blood vessel number in the tumor decreased only in mice receiving the lowest dose (1000 IU) of IFN-beta. IFN-beta with 10 muM of 5-FU frequently induced synergistic antiproliferative effects. IFN-beta with or without 5-FU induces strong antitumor effects in HCC cells, and we conclude that IFN-beta is useful for the prevention and treatment of HCC.

Effects of IFN-alpha on alpha-fetoprotein expressions in hepatocellular carcinoma cells.

We investigated the effects of pegylated (PEG)-IFN-alpha2b on alpha-fetoprotein (AFP) expression as demonstrated by protein and mRNA levels in six human hepatocellular carcinoma (HCC) cell lines. The number of KIM-1 cells in culture with PEG-IFN-alpha2b decreased between 24 amd 240 h, whereas the levels of intracellular and secreted AFP per cellular protein increased (except at 192 h), with levels 1.9-fold and 2.9-fold higher at maximum, respectively, than cells without PEG-IFN-alpha2b (control). The mRNA level increased between 72 and 192 h, when the level was 3-fold higher than that of the control. In the 72-h culture with 40-5000 IU/mL PEG-IFN-alpha2b, there were dose-dependent increases in AFP protein and mRNA expression and dose-dependent decrease in cell number resulting from apoptosis and blockage of the cell cycle at the S-phase. The rate of fucosylated AFP in the cell lysate decreased in a dose-dependent and time-dependent manner. In the PEG-IFN-alpha2b culture of the other five HCC cell lines, cell proliferation was suppressed, but the expressions of AFP protein and mRNA increased in only two cell lines, and suppression of cell proliferation was not related to the increase in AFP expressions. Our findings demonstrated that PEG-IFN-alpha2b induces an increase in AFP expression at both the protein and mRNA levels.

Expression and activation of apoptosis-related molecules involved in interferon-alpha-mediated apoptosis in human liver cancer cells.

Interferon (IFN)-alpha directly inhibits proliferation of liver cancer cells by inducing apoptosis, but the molecular mechanisms by which IFN-alpha induces apoptosis in these cells are not fully understood. We examined the effect of broad spectrum caspase inhibitor, Z-VAD-fmk, and the caspase activation in IFN-alpha-mediated apoptosis by using 4 liver cancer cell lines that were sensitive or resistant to IFN-alpha-mediated apoptosis. Involvement of apoptosis-related mitochondrial proteins and Bcl-2 family proteins in IFN-alpha-mediated apoptosis was further examined in 1 sensitive cell line (KIM-1). The Z-VAD-fmk completely or moderately inhibited IFN-alpha-mediated apoptosis in the sensitive cells. IFN-alpha induced time-dependent activation of caspase-3 in the sensitive cells, while the resistant cells showed mild or no activation. Activation of caspase-9, caspase-8, and caspase-7, and the cleavage of poly(ADP-ribose)polymerase were identified in either or both of the sensitive cell lines, but not in the resistant cells. In KIM-1 cells, the release of cytochrome c and Smac/DIABLO from mitochondria to cytosole was confirmed. Meanwhile, Bcl-xL was upregulated, and Bid activation or translocation, or conformational changes of Bax were not identified. In conclusion, our results suggest IFN-alpha-mediated apoptosis in liver cancer cells involves the mitochondrial apoptotic pathway and is induced by activating various caspases.

IMMUNOHISTOCHEMICAL DETECTION OF VITELLOGENIN IN THE OVARY AND FAT BODY DURING A REPRODUCTIVE CYCLE OF THE COCKROACH, BLATTELLA GERMANICA.

Vitellogenin was immunohistochemically demonstrated in the ovary and fat body during a reproductive cycle. In terminal oocytes of 4-day adults, vitellogenin began to appear in yolk spherules at the cell periphery. The vitellogenin-containing spherules increased in size and number to occupy the whole cell 2 days later. In the female fat body, vitellogenin began to appear in 3-day adults. It was distributed diffusely in the cytoplasm, at a much lower concentration than in the oocytes, during the vitellogenic period. In 11-day adults whose vitellogenesis had terminated, a higher concentration of vitellogenin was found in the cytoplasmic inclusions of the fat body. Vitellogenin was not detected in the male fat body.

Further Evidence for the Presence of a Circadian Clock in the Prothoracic Glands of the Saturniid Moth Samia cynthia ricini: Decapitated Larvae Can Respond to Light-Dark Changes: (circadian clock/prothoracic glands/ecdysone/Samia cynthia ricini).

A small peak of haemolymph ecdysteroid titre precedes the gut purge that characterizes larval-prepupal transition of the saturniid moth Samia cynthia ricini. This peak shifts its phase in parallel with the phase shifts of gut purge according to the changes in light-dark conditions preceding gut purge. Decapitated larvae responded to these light-dark changes as intact larvae did, as assessed by the phase shifts of the haemolymph ecdysteroid peak. This indicates that the brain-centred PTTH clock is not prerequisite for realization of the circadian-clock-controlled timing in the initiation of prepupal development, and supports indirectly our previous notion that the prothoracic glands of Samia possess a circadian clock dictating gut purge timing.

VITELLOGENIN IN THE EGGS OF THE COCKROACH, BLATTELLA GERMANICA: PURIFICATION AND CHARACTERIZATION.

Vitellogenin in the eggs of Blattella germanica was solubilized with solutions at high salt concentrations and high pH. This protein was purified by ammonium sulfate precipitation, acetic acid precipitation, DEAE-cellulose chromatography, and hydroxylapatite chromatography, into a chromatographically homogeneous state. By sucrose density gradient centrifugation, the purified vitellogenin was resolved into two components. The relative amounts of the two components varied according to the pH of the solution. An equilibrium seemed to exist in the interconversion between them when the conditions of the solution were fixed. It is suggested that aggregation and disaggregation of the vitellogenin molecules may account for the apparent heterogeneity.

PURIFICATION AND PROPERTIES OF THE PROTHORACICOTROPIC HORMONE OF THE SILKWORM, BOMBYX MORI.

A simple and highly reproducible procedure for partial purification of prothoracicotropic hormone (PTTH) was established starting with 96,000 male adult Bombyx heads. Approximately 28,500-fold purification of PTTH was accomplished with a yield of about 50% and 6 ng of the most purified preparation ("highly purified PTTH") caused adult development in a brainless Samia pupa. The peptidal nature of PTTH was reconfirmed through the effects of various enzymatic and chemical treatments on the biological activity of "highly purified PTTH". Gel-filtration indicated the molecular weight of PTTH to be 4,400.

The brain neurosecretory cells of the moth Samia cynthia ricini: Immunohistochemical localization and developmental changes of the Samia homologues of the Bombyx prothoracicotropic hormone and bombyxin.

We produced mouse antisera against synthetic peptides corresponding to the sequences of the Samia cynthia ricini homologues of the Bombyx mori PTTH and bombyxin. Immunohistochemical analyses of the Samia cephalic neuroendocrine system using these antisera were performed to identify the neurosecretory cells (NSC) containing the PTTH and bombyxin homologues and to examine the developmental changes in their amounts in the NSC. The results show that the PTTH and bombyxin homologues are produced by two pairs of dorsolateral and 16 pairs of dorsomedial NSC of Samia brain, respectively, and both are transported to, and released from, the corpora allata. No clear-cut correlation was found between the fluctuation in the amount of immunoreactive substances in the brain NSC and the endocrinologically anticipated timings of PTTH secretion. From Samia brain extract, two forms of PTTH activity (∼30 kDa and ∼5 kDa) were resolved through Sephadex gel filtration. The ∼30 kDa and ∼5 kDa PTTH seem to represent the PTTH and bombyxin homologues, respectively. We discuss that the ∼30 kDa PTTH homologue is the true PTTH of Samia.

Changes in the Titer of Bombyxin-Immunoreactive Material in Hemolymph during the Postembryonic Development of the Silkmoth Bombyx mori: (Bombyx moril/bombyxin/monoclonal antibody/radioimmunoassay/hemolymph).

Monoclonal antibodies were raised against pure, native bombyxin-II (bombyxin-II antibody) and against a synthetic nonapeptide corresponding to the amino-terminus of the C-peptide of the bombyxin precursor protein (C-peptide antibody). The bombyxin-II antibody recognized both bombyxin and probombyxin. A radioimmunoassay for bombyxin using the bombyxin-II antibody was developed, and developmental change in the titer of bombyxin immunoreactivity in the Bombyx hemolymph was investigated. The titer was low and almost constant during the fourth and early fifth instars. In the male, the titer rose abruptly 3 days after the beginning of wandering. One day after pupation it rose again steeply to reach the maximal level which lasted until the middle of the developing adult stage. The titer decreased thereafter and increased again at adult emergence. In the female, the pattern of titer fluctuation was similar to that in the male, but the female titers during pupal-adult development were 2-3 times higher than the male titers.

Immunohistochemical Localization of Prothoracicotropic Hormone-Producing Neurosecretory Cells in the Brain of Bombyx mori: (prothoracicotropic hormone/Bombyx mori/monoclonal antibody/brain neurosecretory cell/neurohaemal organ).

A monoclonal antibody that recognized the Bombyx prothoracicotropic hormone (PTTH) was produced by immunizing mice with a synthetic pentadecapeptide corresponding to the amino-terminal portion of Bombyx PTTH. The antibody recognized both intact and reduced forms of PTTH. Immunohistochemistry with this antibody has demonstrated that PTTH is produced by two pairs of dorso-lateral neurosecretory cells of the brain and transported to the corpora allata by axons running through the contralateral hemisphere of the brain. Immunoreactive axon terminals in the corpora allata were localized between the glandular cells, suggesting that PTTH is released at the inner part of this organ.

Developmental Changes in the Bombyxin-and Insulin-like Immunoreactive Neurosecretory System in the Wax Moth, Galleria mellonella: (prothoracicotropins/corpora cardiaca/regulatory peptides/neurohaemal organs/molting control).

Four medial neurosecretory cells (MNC) and 4 lateral neurosecretory cells (LNC) in each brain hemisphere, and one pair of cells in each thoracic ganglion (TG) of Galleria larva react with antibodies against bombyxin and insulin. Material secreted from the MNC and LNC is released mainly in the corpora allata, and that from the TG through the ventral median nerves. Intrinsic secretory cells of the corpora cardiaca (CC) also contain bombyxin-like, but not insulin-like material. The immunoreactivities all disappear during molts and reappear with resumption of feeding. In the MNC and TG they reappear for less than a day, but in cells of the CC immunoreactivity reappears for the whole feeding period. Before pupation, the LNC become temporarily immunopositive towards the end of feeding period, and the MNC and TG during the wandering period, i.e. at the time of prothoracic gland stimulation. Immunoreactivity disappears during the pupal molt. In pupae it is present in the 4 pairs of MNC and 1-2 pairs of LNC 12-48 hr after ecdysis, and in cells of the CC from 12 hr after ecdysis until the end of the pupal instar. In adult, immunoreactivity is restricted to 2 pairs of the LNC and to CC cells.

Cloning of a Gene Encoding Bombyxin, an Insulin-Like Brain Secretory Peptide of the Silkmoth Bombyx mori with Prothoracicotropic Activity: (Bombyx mori/brain peptide/bombyxin/insulin/IGF).

A genomic DNA encoding bombyxin, a 5kD brain peptide of the silkmoth Bornbyx mori with prothoracicotropic hormone activity, has been isolated. The nucleotide sequence coding for bombyxin shows high homology with insulin-gene family members and the overall organization of the preprobombyxin gene is the same as in preproinsulin genes, indicating that bombyxin shares a common ancestral molecule with insulin-family peptides. The bombyxin gene has no intron contrasting to other members of insulin-gene family.