Erratum forTreatment of Rectovaginal Fistula

[This corrects the article DOI: 10.23922/jarc.2023-007.].

Treatment of Rectovaginal Fistula

Rectovaginal fistula (RVF) is a challenging complication with unsatisfactory success and a significant burden for the patients. With insufficient clinical data due to the rare entity, the present state of treatments for RVFs was reviewed especially form the point of factors to determine management, classifications, principle of treatment, conservative and surgical treatments with outcomes. Size, fistula localization and etiology, type of fistula; "simple" or "complex," status of anal sphincter complex and surrounding tissue, presence or absence of inflammation, presence of diverting stoma, previous attempted repair and radiation therapy, patient's condition with co-morbidities, and surgeon's experience are important factors to determine the management of RVF. The inflammation should initially subside in cases with infection. Starting with conservative surgical options and interposing healthy tissue for complex or recurrent fistulas, invasive procedures will be performed if conservative treatment failed. Conservative treatment may be effective in RVFs with minimal symptoms and should be done for small RVFs for a 36 months usual period. Anal sphincter damage might need a repair of sphincter muscles along with RVF repair. Diverting stoma can initially be constructed in patients with severe symptoms and larger RVFs to relief the patient's pain. Simple fistula is usually indicated for local repair. Local repairs to transperineal and transabdominal approaches can be used for complex RVFs. Interposition of healthy, well-vascularized tissue can be required for more complex fistulas and abdominal procedures for high RVFs.

Preoperative underweight is associated with adverse postoperative events in patients undergoing microvascular reconstruction surgery for oral and maxillofacial cancer

We aimed to describe the prevalence of postoperative complications and evaluate its relationship with underweight, obesity, preoperative nutritional status, and systemic inflammation status in patients undergoing microvascular reconstruction for oral and maxillofacial cancer. Patients who were ≥20 years old and underwent microvascular reconstruction surgery between January 2009 to June 2019 were investigated. Patient demographics including body mass index, prognostic nutritional status, and neutrophil-lymphocyte ratio were collected. Logistic regression analysis was applied to evaluate these impacts on postoperative complications. A postoperative complication was defined as a Clavien-Dindo classification more than or equal to II. Of the 145 patients included in the analysis, 83 patients (57.2%) experienced postoperative complications, belonging to a Clavien-Dindo classification Ⅱ (n=71), Ⅲb (n=11), and Ⅳa (n=1). Multiple logistic regression revealed that a body mass index less than 18.5 kg/m² (odds ratio 6.19, 95% confidential interval 1.34-28.6, P=0.02) was related to postoperative complications. Another multiple logistic regression model including all explanatory factors found that underweight (P=0.03) was related to postoperative complications. This retrospective study showed that preoperative underweight was associated with postoperative complications as evaluated by the Clavien-Dindo classification.

Prognostic Significance of ZKSCAN3 (ZNF306) Expression in Gastric Carcinoma

BACKGROUND/AIM

Zinc finger protein ZKSCAN3 (ZNF306) is a promising oncogene candidate in colon, bladder, breast, uterine cervical, and prostate cancers. The present study aimed to investigate ZKSCAN3 protein expression in gastric carcinoma patient tissues and to evaluate oncological outcomes in these patients.

MATERIALS AND METHODS

ZKSCAN3 was detected using the anti-ZKSCAN3 rabbit polyclonal antibody. For immunohistochemical examination, we used paraffin-embedded specimens from 87 consecutive patients with gastric cancer who underwent gastrectomy. We investigated ZKSCAN3 expression in relation with patient prognosis and clinicopathological factors.

RESULTS

ZKSCAN3 was detected in 28 (32.2%) tumour specimens, with significant association with lymphatic system invasion and distant metastasis. Patients with ZKSCAN3-positive tumours had worse overall survival (OS) than those with ZKSCAN3-negative tumours based on log-rank testing. Furthermore, multivariate analysis revealed that ZKSCAN3 was an independent prognostic parameter for OS (hazard ratio: 2.6379, p=0.0164).

CONCLUSION

ZKSCAN3 is a potential novel prognostic factor in gastric cancer patients.

Evaluation of screening for drug use using postmortem prolactin levels in serum and cerebrospinal fluid

Prolactin (PRL) levels can usually be controlled by PRL-inhibiting psychiatric drugs that include anti-dopamine agents. However, the use of dopamine (DA) antagonists may lead to hyperprolactinemia under certain clinical conditions. The aim of this study was to investigate postmortem PRL levels as potential markers of drug abuse, especially that of DA antagonists, in autopsy cases. We examined 121 autopsy cases, excluding cases involving acute hypoxia/ischemia, such as asphyxia, because PRL concentrations are reportedly increased under acute hypoxic conditions. Detected drugs were classified as either DA antagonists, stimulants, psychotropic drugs other than DA antagonists, or other non-psychotropic drugs, and many cases had no detected drugs. Samples comprised blood collected from the right heart chamber and cerebrospinal fluid (CSF). PRL protein level was measured by chemiluminescent immunoassay, and PRL gene expression in the anterior pituitary of autopsy cases was analyzed by reverse transcription-polymerase chain reaction. The PRL-positive cell ratio in the anterior pituitary gland was also measured by immunohistochemical analysis. The results indicated that PRL levels in the serum and CSF were higher in DA antagonist cases than in other cases. PRL levels in the serum and CSF also correlated with the PRL gene expression in cases with abuse of DA antagonists. However, no significant difference in the PRL-positive cell ratio in the anterior pituitary gland was evident between any of the classes of drug-detected and drug-undetected cases. These results suggest that postmortem measurements of PRL transcription levels may be useful for diagnosing cases of DA antagonist use.

Sentinel Node Navigation Surgery for Early Gastric Cancer: Analysis of Factors Which Affect Direction of Lymphatic Drainage

BACKGROUND AND PURPOSE

We started performing sentinel node navigation surgery (SNNS) for patients with early gastric cancer (EGC) using infrared ray electronic endoscopy (IREE) with indocyanine green injection from year 2000. The EGCs usually have complex lymphatic drainage, unidirectional or multidirectional lymphatic flow. In this study, we investigated and clarified factors that affect the direction of gastric lymphatic drainage.

PATIENTS AND METHOD

Consecutive 60 patients with EGC who underwent SNNS by IREE from year 2006 to 2014 were enrolled to this study. Patients' age, gender, location of tumors, operative method, previous treatment by endoscopic submucosal dissection (ESD), presence of pathological ulcerative scar and maximum tumor diameter were enrolled as parameters which may affect direction of lymphatic drainage and analyzed.

RESULT

Bivariate analysis demonstrated that the presence of pathological ulcerative scar (P = 0.01), tumor location (g.c vs. a.w vs. p.w vs. l.c, P = 0.01), and maxim tumor diameter (P = 0.0003) were relevant to direction of gastric lymphatic drainage. Multivariate analysis showed that tumor location (g.c/a.w/p.w vs. l.c, odds ratio 8.227, P = 0.011) and the maximum tumor diameter (odds ratio 1.057, P = 0.037) are independent factors that affect direction of gastric lymphatic flow. Of tumors, 78% located at lesser curvature had unidirectional lymphatic drainage, and 93% of tumors whose diameter was 40 mm and more had multidirectional lymphatic drainage.

CONCLUSION

Our investigation revealed that the tumor location and tumor diameter were the key factors which affect the direction of lymphatic drainage, which is useful fact to understand the complexity of gastric lymphatic drainage.

Prediction of lymph node metastasis and sentinel node navigation surgery for patients with early-stage gastric cancer

Accurate prediction of lymph node (LN) status is crucially important for appropriate treatment planning in patients with early gastric cancer (EGC). However, consensus on patient and tumor characteristics associated with LN metastasis are yet to be reached. Through systematic search, we identified several independent variables associated with LN metastasis in EGC, which should be included in future research to assess which of these variables remain as significant predictors of LN metastasis. On the other hand, even if we use these promising parameters, we should realize the limitation and the difficulty of predicting LN metastasis accurately. The sentinel LN (SLN) is defined as first possible site to receive cancer cells along the route of lymphatic drainage from the primary tumor. The absence of metastasis in SLN is believed to correlate with the absence of metastasis in downstream LNs. In this review, we have attempted to focus on several independent parameters which have close relationship between tumor and LN metastasis in EGC. In addition, we evaluated the history of sentinel node navigation surgery and the usefulness for EGC.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

Prognostic significance of ZNF217 expression in gastric carcinoma

BACKGROUND

The zinc finger protein ZNF217 is a candidate oncogene in breast cancer and ovarian clear cell cancer. The purpose of the present study was to clarify the significance of this protein's expression in gastric carcinoma and to evaluate the outcome of these patients.

MATERIALS AND METHODS

Using paraffin-embedded specimens from 84 patients with gastric cancer, ZNF217 protein was detected using an anti-ZNF217 goat polyclonal antibody. We evaluated the ZNF217 protein expression in relation to patient outcome and clinicopathological parameters.

RESULTS

The ZNF217 protein was expressed in 34 (40.5%) tumor sections. Patients with ZNF217-negative tumors had better relapse-free survival (RFS) and overall survival (OS) than those with ZNF217-positive tumors by the log-rank test. Notably, multivariate analysis indicated that ZNF217 was an independent prognostic factor for RFS.

CONCLUSION

ZNF217 expression seems to be a novel prognostic biomarker in gastric cancer.

Prediction of lymph node metastasis in patients with submucosa-invading early gastric cancer

BACKGROUND AND AIM

Early gastric cancer (EGC), with wall invasion limited to the submucosa, has approximately 15 to 20% chance of lymph node metastasis. The purpose of this study is to clarify the parameters which affect lymph node metastasis and survey whether lymph node metastasis can be predicted preoperatively.

PATIENTS AND METHODS

We retrospectively analyzed 145 consecutive patients with EGC using multivariate analysis and developed a formula which predicts lymph node metastasis by linear discriminant analysis. In addition, we prospectively validated this formula in another subset of 106 consecutive patients with EGC and compared the predicted with the actual pathological lymph node metastasis.

RESULTS

Multivariate analyses revealed that independent factors, which affect lymph node metastasis for EGC, were lymphatic system invasion (p=0.00002, odds ratio 3.11) and venous system invasion (p=0.039, odds ratio 2.44). In addition, we developed the lymph node metastasis-predicting formula using these two factors by linear discriminant analysis. The formula is as follows: Y=0.12 × (venous system invasion: 0, 1, 2 or 3) + 0.19 × (lymphatic system invasion: 0, 1, 2, or 3) - 0.14. If Y>0, we judge that a patient with gastric cancer is susceptible lymph node metastasis. The result of this prospective study showed that the sensitivity and specificity rates were 70% and 61.6%, respectively.

CONCLUSION

We developed a formula which can predict lymph node metastasis using linear discriminant analysis. This formula seems useful in predicting for lymph node metastasis in patients with EGC.

Sentinel lymph node navigation surgery for early stage gastric cancer

We attempted to evaluate the history of sentinel node navigation surgery (SNNS), technical aspects, tracers, and clinical applications of SNNS using Infrared Ray Electronic Endoscopes (IREE) combined with Indocyanine Green (ICG). The sentinel lymph node (SLN) is defined as a first lymph node (LN) which receives cancer cells from a primary tumor. Reports on clinical application of SNNS for gastric cancers started to appear since early 2000s. Two prospective multicenter trials of SNNS for gastric cancer have also been accomplished in Japan. Kitagawa et al reported that the endoscopic dual (dye and radioisotope) tracer method for SN biopsy was confirmed acceptable and effective when applied to the early-stage gastric cancer (EGC). We have previously reported the usefulness of SNNS in gastrointestinal cancer using ICG as a tracer, combined with IREE (Olympus Optical, Tokyo, Japan) to detect SLN. LN metastasis rate of EGC is low. Hence, clinical application of SNNS for EGC might lead us to avoid unnecessary LN dissection, which could preserve the patient's quality of life after operation. The most ideal method of SNNS should allow secure and accurate detection of SLN, and real time observation of lymphatic flow during operation.

High UBCH10 protein expression as a marker of poor prognosis in esophageal squamous cell carcinoma

BACKGROUND/AIM

Ubiquitin-conjugating enzyme H10 (UBCH10) is required in the cell-cycle transition from metaphase to anaphase. Therefore, we investigated whether its expression level in cancerous esophageal lesions affected prognosis of patients with esophageal squamous-cell carcinoma.

MATERIALS AND METHODS

Paraffin-embedded tissue samples from 121 patients with esophageal squamous cell carcinoma were stained with antibody to UBCH10 for immunohistochemical analysis.

RESULTS

UBCH10 was expressed in cancerous and dysplastic lesions, but not in normal tissue. Patients were grouped according to expression: High (N=33) or low (N=88), depending on the staining pattern. There were significant differences between the groups in terms of invasion into lymphatic vessels, number of metastatic lymph nodes, TNM classification, and stages, as well as in survival: the 50% survival rate in the high expression group was 2.3 years, whereas it was 9.9 years for the low-expression group (p<0.0001). Even with multivariate adjusting for stage 0 to stage IV using the Cox proportional hazard model, patients belonging to the high-expression group had a poor prognosis (Hazard ratio=2.5; 95% Confidence Interval=1.3-4.5; p=0.004).

CONCLUSION

High protein expression of UBCH10 is a marker of poor prognosis in esophageal squamous cell carcinoma.

Reduced expression of Rho GDP dissociation inhibitor 2 mRNA is associated with lymph node metastasis in gastric carcinoma

Small GTPase proteins, including RhoA, RhoB, RhoC, Rac1 and cdc42, are molecules that have significant roles in linking cell shape and cell cycle progression in cytoskeletal arrangements and mitogenic signaling. Rho GDP dissociation inhibitor 2 (RhoGDI2) has recently been identified as a metastasis suppressor gene in models of bladder cancer. RhoGDI2 has also been identified as a potential regulator of tumorigenesis and cancer progression. The present study aimed to clarify the significance of RhoGDI2 gene expression in gastric carcinoma and to evaluate the outcome of affected patients. A total of 46 pairs of normal mucosa and cancer specimens were obtained from patients who had undergone a gastrectomy for primary gastric carcinoma and were subjected to semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) for RhoGDI2. The expression of RhoGDI2 mRNA was significantly higher in early-stage gastric cancer specimens compared with the normal gastric epithelium samples. By contrast, the depth of the tumor was negatively correlated with RhoGDI2 mRNA expression. In addition, a reduced expression of RhoGDI2 mRNA was associated with venous system invasion and lymph node metastasis. RhoGDI2 mRNA was more frequently expressed in differentiated adenocarcinoma compared with poorly-differentiated adenocarcinoma. Although the statistical significance was not established, RhoGDI2-positive patients tended to have a superior oncological outcome compared with RhoGDI2-negative patients. The reduced expression of RhoGDI2 mRNA in gastric carcinoma is associated with venous system invasion and lymph node metastasis.

Preoperative determination of appropriate cutting line for proximal gastrectomy to avoid postoperative jejunal ulcer

BACKGROUND/AIMS

Although proximal gastrectomy has become a procedure of choice for patients' early cancer in the upper third of stomach, no clinical guide for optimal gastric resection in order to avoid postoperative jejunal ulcer is available. The aim of this study was to investigate whether determining the distribution of parietal and chief cells of the stomach using Congo red test is clinically relevant.

METHODOLOGY

The F-line was defined as a boundary line between fundic and intermediate area of the stomach according to the pathological findings in 29 patients who underwent total gastrectomy for early gastric cancer, whereas the f-line was regarded as a boundary line between intermediate and pyloric area. In the additional 6 patients undergoing vagus-preserving proximal gastrectomy with jejunal pouch interposition, endoscopic Congo red test was preoperatively performed to determine the F-f-line.

RESULTS

The distances from the pyloric ring to f-line on the lesser and greater curvatures were variable. Long-term outcomes of proximal gastrectomy guided by preoperative endoscopic Congo red test were favorable.

CONCLUSIONS

It is suggested that preoperative endoscopic Congo red test is useful to determine the appropriate cutting line in order to avoid postoperative jejunal ulcer after proximal gastrectomy.

Clinical significance of Rho GDP dissociation inhibitor 2 in colorectal carcinoma

BACKGROUND

Small GTPase proteins, including RhoA, RhoB, RhoC, Rac1, and cdc42, are important molecules for linking cell shape and cell-cycle progression because of their role in both cytoskeletal arrangements and mitogenic signaling. Over-expression of wild-type or constitutively active forms of RhoA has been shown to induce invasive behavior in non-invasive rat hepatoma cells in vitro. In addition, over-expression of RhoC has been found in melanoma cells with increasing metastatic activity as well as inflammatory breast cancer. These results indicate that overexpression of Rho proteins contributes to cancer cell invasion and metastasis. Rho GDP dissociation inhibitor 2 (RhoGDI2) was recently shown to act as a metastasis suppressor gene in bladder cancer. The purpose of this study was to clarify the clinical significance of this gene expression in patients with colorectal carcinoma.

METHODS

Fifty pairs of normal mucosa and cancer specimens obtained at the time of surgery from patients with colorectal cancer (CRC) were subjected to reverse transcription-polymerase chain reaction for RhoGDI2.

RESULTS

No patients with RhoGDI2-higher expression tumors had liver metastasis (0 in 8 cases); however, 33.3% (14 in 42 cases) of patients with RhoGDI2-lower expression tumors had liver metastasis. With regard to outcome in relation to RhoGDI2-positivity, RhoGDI2-higher expression tumors had a significant correlation with superior relapse-free survival (RFS) time as compared to RhoGDI2-lower expression tumors in stage III CRC (log-rank test, P < 0.05). Moreover, multivariate analysis indicated that RhoGDI2 was an independent prognostic factor for RFS.

CONCLUSION

RhoGDI2 is a novel predictor of RFS in patients with colorectal carcinoma.

Pre-pyloric site gastric cancer after pylorus-preserving gastrectomy (PPG): a case report

Pylorus-preserving gastrectomy (PPG) is a function-preserving surgical procedure which is now applied to treat early gastric cancer in the mid-portion of the stomach. We report a patient who developed a pre-pyloric site gastric cancer after PPG. To our knowledge, this is the first report on the development of pre-pyloric site gastric cancer after PPG in the English literature using PubMed.

Frequent splicing aberration of the base excision repair gene hMYH in human gastric cancer

BACKGROUND

Missense mutation of hMYH, which prevents transversion mutations induced by oxidative DNA damage, is reportedly associated with the development of gastric and colon cancer. We investigated whether deficiency or mutation of hMYH is associated with gastric carcinogenesis.

PATIENTS AND METHODS

Thirty patients with gastric carcinoma, three gastric cancer cell lines and lymphocytes from three healthy volunteers were investigated. Reverse transcription-polymerase chain reaction (RT-PCR) was performed for hMYH, and the full-length sequence of hMYH mRNA was analysed.

RESULTS

A silent mutation at codon 473 was seen in two tumours. Single nucleotide polymorphism at codon 345 was observed in 14 patients. These two base substitutions had no pathogenic effect. Seven splice variants were observed and two aberrant transcripts were detected more frequently in cancer specimens (67%) than in normal mucosa (10%).

CONCLUSION

The high frequency of splicing aberration in cancer tissues suggests that aberrant transcripts may be involved in gastric carcinogenesis and cancer development.

Expression of vascular endothelial growth factor (VEGF)-C and -D in gastric carcinoma

BACKGROUND

Both vascular endothelial growth factor (VEGF)-C and (VEGF)-D are ligands of VEGF receptor (VEGFR)-3 (Flt-4) and VEGFR-2 (KDR/FLK-1) and are supposed to participate in lymphangiogenesis. The purpose of this study was to clarify the clinical significance of the expression of these factors and to evaluate their relationship with prognosis in patients with gastric carcinoma.

METHODS

Fifty pairs of normal mucosa and cancer specimens were obtained from patients who had undergone gastrectomy for primary gastric carcinoma and subjected to reverse transcriptase-polymerase chain reaction for VEGF-C, VEGF-D, and VEGFR-3.

RESULTS

Both VEGF-C and VEGF-D mRNA expression significantly correlated with lymphatic invasion (P < 0.05). Although VEGF-C and -D were concomitantly expressed in most cases, only VEGF-C expression was related to lymph node metastasis. VEGFR-3 expression was associated both with VEGF-C and VEGF-D expression, but not with lymph node metastasis. Tumors expressing these mRNAs tended to correlate with poorer prognosis, but the relationships were not statistically significant.

CONCLUSION

Our study suggests that both VEGF-C and VEGF-D are involved in lymphatic spreading of gastric cancer cells, which is clinically useful for the evaluation of lymphatic invasion in patients with gastric carcinoma.

Prognostic significance of vascular endothelial growth factor D in gastric carcinoma

The angiogenic factor called vascular endothelial growth factor (VEGF)-D is a ligand for VEGF receptor-2 (VEGFR-2/KDR) and receptor-3 (VEGFR-3/Flt-4). It is implicated in the development of lymphatic vessels and promotion of lymphatic metastasis. The purpose of this study was to investigate the prognostic significance of VEGF-D expression in patients with gastric carcinoma. We assessed the expression of VEGF-D in gastric carcinoma by immunohistochemistry on 143 consecutive patients' stored sections and evaluated the lymphatic vessel count (LVC) in tumors using the novel selective lymphatic endothelium marker D2-40. VEGF-D expression was observed in 55 (39%) tumor sections. The expression of VEGF-D correlated significantly with tumor size, T of the TNM classification, lymphatic and venous system invasion, LVC, lymph node metastasis, M of TNM, and pTNM stage. Multivariate analysis indicated that VEGF-D expression was an independent prognostic factor for both relapse-free survival (RFS) and overall survival (OS). Our data indicate the involvement of VEGF-D in tumor progression via lymphoangiogenic pathways. Practically, VEGF-D expression can be useful for predicting RFS and OS in patients with gastric carcinoma.

[An analysis of nutritional status and pulmonary hypertension in patients with sequela of pulmonary tuberculosis and chronic obstructive pulmonary disease]

The prognostic value of hypercapnia and/or pulmonary hypertension differs in patients with sequela of pulmonary tuberculosis (TBseq) and those with chronic obstructive pulmonary disease (COPD) who are receiving home oxygen therapy (HOT). In an attempt to identify the factors, if any, that might explain this difference, we first compared nutritional status, respiratory function test results, dyspnea indexes, and other data for hypercapnic patients (PaCO2 > or = 45 Torr) and normocapnic patients (PaCO2 < 45 Torr) receiving HOT. Second, we examined the relationship between the degree of pulmonary hypertension and several respiratory function parameters for patients in each disease category. In 44 patients with TBseq, nutritional status estimated by body mass index and serum albumin was significantly better in the hypercapnic patients than in the normocapnic patients. However, this difference was not observed in 37 patients with COPD. In 30 patients with TBseq, the degree of pulmonary hypertension correlated significantly only with PaO2; in 32 patients with COPD, however, significant correlations were observed not only with PaO2 but also with PaCO2, %VC, and FEV1. These differences distinguishing groups of patients with the 2 diseases may provide an explanatory basis for the difference in prognostic value of hypercapnia and/or pulmonary hypertension in patients receiving HOT.

Structure of the L-histidine decarboxylase gene

Two species of L-histidine decarboxylase (HDC) mRNA were found in the KU-812-F basophilic cell line, but only the 2.4-kilobase (kb) one encodes the functional HDC (Mamune-Sato, R., Yamauchi, K., Tanno, Y., Ohkawara, Y., Ohtsu, H., Katayose, D., Maeyama, K., Watanabe, T., Shibahara, S., and Takishima, T. (1992) Eur. J. Biochem. 209, 533-539). The 3.4-kb one encodes a truncated HDC protein and is also found in human leukemia-derived cell lines HEL and KCL-22. To clarify the mechanisms that regulate transcription of the HDC gene and generate the two species of mRNA, we have isolated genomic DNA clones coding for the HDC from human genomic libraries. Structural analysis of the isolated clones revealed that the human HDC gene is composed of 12 exons spanning approximately 24 kb. Genomic DNA blot analysis suggested that HDC is encoded by a single copy gene. The structural analysis also demonstrated that the heterogeneity of the HDC mRNA is caused by an insertion of the seventh intron sequence and alternative use of the splicing acceptor site at the 12th exon. The transcription start site of the HDC gene and the nucleotide sequences of the promoter and first exon regions were determined. We found a TATA-like sequence, a GC box, four CACC boxes, four GATA consensus sequences, and six leader-binding protein-1 binding motifs in the promoter region of the HDC gene.

Age-related variation of respiratory chemosensitivity in monozygotic twins

To examine age-related variations in respiratory chemosensitivity to hypoxia and hypercapnia, the magnitudes of within-pair variances for ventilatory responses to hypoxia and hypercapnia were measured in 38 pairs of male monozygotic twins. Mean values for the slope factor of end-tidal PO2-ventilation hyperbola (A) were larger in Group I (13 pairs with a mean age of 16.3 +/- SD 0.9 yr) than those in Group II (12 pairs with a mean age of 29.8 +/- 6 yr), and Group III (13 pairs with a mean age of 46 +/- 7.2 yr). The slope factors for end-tidal PCO2-ventilation line (S) were similar among the 3 groups. Within-pair variances for A, A/body surface area (BSA), and Vo (asymptote for ventilation when end-tidal PO2 is infinite) were larger in Groups II and III than in Group I. Within-pair variances for S and S/BSA were also larger in Groups II and III than in Group I, whereas within-pair variances for B (intercept with end-tidal PCO2) were similar among the 3 groups. These results indicate that variations for respiratory chemosensitivity to hypoxia increase during the period from adolescence to adulthood and stay at a similar level thereafter. Variations of hypercapnic chemosensitivity also increase during this period, attenuating thereafter; however, the variation is 7 times larger than that of hypoxic chemosensitivity in the third and fourth decades.

Pattern of genetic influence on pulmonary function

Whether genetic factors influence small airway function and lung volume was examined in 20 adolescent (mean age, 16.2 +/- SD 1.1 years) monozygotic twin pairs, 11 adolescent (mean age, 16.7 +/- 0.7 years) dizygotic twin pairs, and 20 adult (mean age, 38.7 +/- 9.3 years) monozygotic twin pairs. Within-pair variances of adolescent dizygotic twins for height, FVC, FEV1/FVC, V50, V25, V50/FVC, FRC, and delta N2 were significantly larger than those of adolescent monozygotic twins, indicating that these pulmonary function variables are influenced predominantly by genetic factors in adolescence. Within-pair variances of adult monozygotic twins were similar to those of adolescent monozygotic twins in terms of V50 and V25, indicating that these pulmonary function variables are influenced predominantly by genetic factors in adulthood. These results indicate that small airway dynamics, in terms of V50 and V25, are influenced in larger part by genetic factors in adolescence as well as adulthood, whereas lung volumes in terms of FRC and FVC are controlled by genetics only in adolescence.

Chemical and behavioral control of breathing in adult twins

Whether genetic influence on chemical and behavioral control of breathing is still present in adulthood was examined in 28 pairs of monozygotic (mean age, 40 +/- SD 9.9 yr) and 10 dizygotic (35 +/- 9.3 yr) twins. Mean values for hypoxic and hypercapnic ventilatory responses, threshold for perceiving added inspiratory resistance, and respiratory patterns were not different between monozygotic and dizygotic twins. However, within-pair variance ratios (those in monozygotic twins being denominators) for hypoxic response (4.08, p less than 0.005), hypercapnic response (4.89, p less than 0.005), respiratory frequency during air breathing (3.96, p less than 0.005), inspiratory time during air breathing (5.47, p less than 0.005), and inspiratory time during hypoxia (9.08, p less than 0.005) were significantly larger than 1. Within-pair variances for threshold for resistive load perception and respiratory pattern during hypercapnia were equivalent between the 2 groups. These results indicate that ventilatory responses to hypoxia and hypercapnia and respiratory patterns while breathing air include genetically determined factors, whereas perception threshold for added resistance and respiratory patterns during hypercapnia are influenced predominantly by environmental force in adulthood.

Genetic and environmental influence on inspiratory resistive load detection

To differentiate genetic factors from environmental forces in determining threshold for resistance load detection (RLD), 62 healthy adolescent twins (mean age = 16 years) and 74 healthy adult twins (mean age = 34 years) were studied by the standard psychophysical technique. The zygosity was determined by blood groups, finger prints, and physical appearances. Mean values for age, height, weight, pulmonary functions (FVC, FEV1, FEV1/FVC, Raw, and FRC) were not different between monozygotic (MZ) and dizygotic (DZ) pairs either in adolescent or adult twins. Threshold for RLD was analyzed in terms of added resistance divided by airway resistance plus apparatus resistance (Weber fraction) and mouth pressure (P) at the threshold. Both Weber fraction and P were equivalent between MZ and DZ either in adolescent or adult twins. In adolescence, within-pair variance for P was significantly greater in DZ than in MZ, but within-pair variances for Weber fraction were similar between MZ and DZ, the former indicating that threshold for RLD is predominantly influenced by genetic factors. In adults, within-pair variances for Weber fraction and P were not different between MZ and DZ, indicating that environmental factors predominate over genetic factors. When adolescent and adult twins were lumped together, mean values for Weber fraction and P were not different between male and female. Relationship between P and age was significant both in male and female. P (male) = 0.281 + 0.013 X age (years) +/- SD 0.36 cm H2O, and P (female) = 0.235 + 0.013 X age (years) +/- 0.48 cm H2O. These results indicate that the threshold for RLD is influenced predominantly by genetic factors in adolescence, but environmental factors predominate in the adult. Although sex difference is not clear, P at the threshold increases with age in both sexes.

Respiratory chemosensitivity in smokers. Studies on monozygotic twins

Whether smoking habits influence ventilatory response to hypoxia and hypercapnia was examined in 23 pairs (8 concordant smoker pairs, 8 concordant nonsmoker pairs, and 7 discordant pairs) of monozygotic twins. Pulmonary function tests were also performed. Smokers (7 subjects) were significantly taller by 2 cm (mean value) than nonsmoker partners (7 subjects). Arterial pH of smokers was significantly lower, although it stayed within normal range. Closing volume to vital capacity ratio tended to be larger in smokers. Ventilatory response to hypoxia (slope factors for ventilation-alveolar Po2 curve and ventilation-arterial O2 saturation line) was significantly higher in smoking than in nonsmoking partners, whereas ventilatory response to hypercapnia (slope factor for ventilation-alveolar Pco2 line) was not different. Intrapair variances for height and ventilatory response to hypoxia were larger in discordant pairs with respect to smoking than in concordant pairs. These results indicate that smoking habits influence the slope, without the parallel shift, of the hypoxic ventilatory response curve.

[Evaluation of pulmonary function parameters in twins]

The purpose of this study was to determine the role of genetic influence on the variability of pulmonary function tests in normal individuals. Thirty-one pairs of twins (20 monozygotes (MZ) and 11 dizygotes (DZ) of both sexes, ranging in age from 15 to 18 years, were tested. Degree of similarity in each parameter was compared between MZ pairs and DZ pairs by within-pair variance ratio (MWDZ/MWMZ). The within-pair variances of MZ were smaller than DZ with respect to FVC, FEV1/FVC, V50, V25, delta N2 and FRC. These parameters were corrected for height; again the within-pair variances of MZ were smaller than DZ with respect to all the parameters except for FRC. The results indicate that these parameters were at least partly determined by genetic factor. However the within-pair variance of FEV1, PF, CV/VC, Raw, Pao2, Paco2, pH, and [HCO3-] were not different between the two groups. To estimate the similarity within MZ pairs, among-pair to within-pair variance ratio (MAMZ/MWMZ) were used. All the parameters of pulmonary mechanics showed similarity within pairs. Arterial pH and Pao2 also disclosed a significant similarity within-pairs, but Paco2 and [HCO3-] did not.

Familial factors affecting arterial blood gas values and respiratory chemosensitivity in chronic obstructive pulmonary disease

Arterial blood gas determinations in patients with chronic obstructive pulmonary disease (COPD) and respiratory chemosensitivity, and arterial blood gas determinations in their sons were compared. Patients with silicosis (n=17) and their sons (n=22) served as control subjects. Arterial blood gases, pH, and HCO-3 concentration in 25 patients with COPD were averaged from at least 3 determinations (mean sample number, 10.1) to compare with the data on their sons (n-34; mean age, 33.9 yr). The Paco2 obtained during stable stages correlated positively between patients with COPD and their sons. The Pao2 of patients with COPD in stable stages correlated with the hypoxic ventilatory response of their sons. The Paco2 and Paco2 obtained during acute exacerbation of COPD correlated with the hypoxic ventilatory response of the sons. Deviations in FEV1 and V25 from predicted values correlated with deviations in Pao2 in the sons of the patients with COPD. In silicosis, significant relationships between patients and sons were not seen with respect to arterial blood gas determinations and ventilatory responses except for Paco2 of patients and hypercapnic ventilatory responses of sons. Smoking habits did not correlate between patients and sons both in COPD and in silicosis. However, the concordance ratio of smokers or nonsmokers between patients and sons was higher in COPD than in silicosis. These results indicate that familial factors are involved in determining the arterial blood gases and ventilatory response to hypoxia in COPD, and blunted chemosensitivity to hypoxia and incipient airway dysfunction antedate clinically manifest COPD.

Control of breathing in young twins

To clarify the role of genetics in determining chemical and behavioral control of breathing, an age-, body size-, and sex ratio-matched study was conducted in 62 twins (mean age 16.4 yr, 20 pairs of monozygotic twins (MZ) and 11 pairs of dizygotic twins (DZ)] for ventilatory responses to hypoxia (A) and hypercapnia (S) along with thresholds for perception of added inspiratory resistance. A and S were determined by a dual-control system developed to regulate arterial blood gases at predetermined levels. Mean values for A, S, thresholds for added resistance, and mouth pressure at the threshold were not different between MZ and DZ. Within-pair variances for A, S, and mouth pressure at the threshold were significantly smaller in MZ than DZ. Neither A nor S correlated with thresholds for resistance and mouth pressure in either MZ or DZ. These results indicate that in adolescent twins sensitivity to added inspiratory resistance and chemosensitivity to hypoxia and hypercapnia involve genetically determined factors, and perception of added inspiratory resistance is not directly related to chemical control of breathing.

Genetic aspects of serum immunoglobulins and respiratory chemosensitivity

The role of genetics and environmental factors determining serum concentrations of immunoglobulins (IgA, IgG, and IgM,) were analyzed in 20 pairs of monozygotic (MZ) and 11 pairs of dizygotic (DZ) twins. Respiratory chemosensitivity to hypoxia and hypercapnia was also measured. Intrapair variances for alpha 2-, beta-, and gamma-globulins, IgG, IgA, and IgM were significantly smaller than interpair variances in MZ, indicating that these variables are more similar between pairs than among pairs in MZ. In DZ, intrapair variance for IgM was significantly smaller than interpair variance. Intrapair variance in MZ for gamma-globulin, IgG, IgA, hypoxic ventilatory response, and hypercapnic ventilatory response were significantly smaller than those in DZ, indicating that these variables are genetically controlled. Subjects with low IgA showed a blunted hypoxic ventilatory response, and subjects with high IgA, a vigorous ventilatory response. These results indicate that while IgM is controlled predominantly by environmental factors, IgA and IgG are genetically determined in young healthy subjects. Serum IgA levels and hypoxic ventilatory response are interrelated in young healthy subjects.

Familial aggregation of abnormal ventilatory control and pulmonary function in chronic obstructive pulmonary disease

A sex-, age-, obesity, and protease inhibitor-matched study of pulmonary function and ventilatory control was performed on 26 sons of 19 patients with chronic obstructive pulmonary disease (COPD) and 26 control subjects. Mean values for FEV1/FVC and V25 were significantly lower and CV/VC was significantly higher in sons of patients than in the controls. VC, airway resistance, static pulmonary compliance. delta N2, arterial blood gases and pH were not different between sons and controls. When the sons of patients were divided into two groups according to the arterial blood gases of their parents, sons of hypoxemic, hypercapnic parents showed significantly lower hypoxic ventilatory responses than sons of normoxemic, normocapnic parents. Hypercapnic ventilatory responses were not different between sons and controls. Abnormal pulmonary function and low ventilatory responses were more frequently detected in sons than in controls. The association of smoking with abnormalities of pulmonary function was not clearly seen in sons. These results suggest that familial factors (either genetic or environmental) play a significant role in determining the pathogenesis and clinical types of COPD.

Relationship between hypoxic and hypercapnic ventilatory responses in man

Ventilatory responses to hypoxia (A) and hypercapnia (S) were measured in 127 healthy men (105 males and 22 females) by a dual control system for regulating Pa O2 and Pa CO2 simultaneously and independently of each other. The subjects were classified into groups according to sex, age, family history, and genetics (twins). Mean values for A were 138 +/- SD 93 liters/min.mmHg in group I (subjects without family history of chronic lung diseases) and 80 +/- 56 liters/min.mmHg in group II (sons of patients with chronic obstructive pulmonary disease or silicosis). The difference was highly significant (P less than 0.001). Mean S were 1.11 +/- 0.39 liters/min.mmHg-1 in group I and 1.16 +/- 0.48 liters/min.mmHg-1 in group H. The difference was not significant. Mean values for A and S in the aged males (mean age = 71.3 years) did not differ from those in 15 adult males (mean age = 29.5 years) and 60 young twins (mean age = 16.4 years). In every respect of age, sex, familial factors, and genetics, A and S were not interrelated. Mouth occlusion pressure (P0.1) was measured during air breathing and it correlated neither with A nor S. These results indicate 1) hypoxic and hypercapnic responses are not strongly related to each other, and 2) the aging process does not alter ventilatory responses to hypoxia and hypercapnia.

The effects of posture on capillary blood flow pulse and gas exchange in the lungs of man

Cardiac output and pulmonary capillary blood flow were measured on 5 normal subjects to dye dilution and N2O-body plethysmograph method, respectively. To facilitate calculations and to improve signal to noise ratio, a computer of average transient was used. Cardiac output increased from 7.16 +/- SEM 0.86 L/min to 8.46 +/- 0.72 L/min after the subject changed his posture from upright to supine. Pulmonary capillary blood flow also increased from 5.2 +4- 0.44 L/min to 6.95 +/- 0.48 L/min. These changes were mostly due to changes in stroke volume. The differences between cardiac output and pulmonary capillary blood flow were 19% and 15% in upright and supine positions, respectively. Conduction time of blood flow pulse from pulmonic valve to pulmonary capillary beds prolonged significantly in supine position. Flow acceleration and pulsatility index did not change by posture. Changes in flow acceleration and changes in PaO2 were significantly correlated. These results indicate: 1) profiles of pulmonary capillary blood flow pulse do not alter by posture except conduction time, 2) zone I which is normally closed because of gravity in upright position seems to recruit in supine position, and 3) blood flow acceleration is responsible at least partially for postural changes in PaO2.