Eight structurally diverse components with anti-acetylcholinesterase activity from Daphne bholua

Eight structurally diverse components, including six undescribed ones, (±)-daphuarin A (1a/1b), daphuarin B (2), daphuarin D-E (4-6), together with a pair of new natural products (±)-daphuarin C (3a/3b) were isolated from the herb of Daphne bholua Buch.-Ham. ex D. Don. Their planar structures were elucidated by extensive spectroscopic analyses. The configurations were established with the assistance of quantum chemical calculations, together with the Custom DP4+ method. The inhibitory potentials of all isolates against acetylcholinesterase were evaluated.

Camrelizumab and apatinib plus induction chemotherapy and concurrent chemoradiotherapy in stage N3 nasopharyngeal carcinoma: a phase 2 clinical trial

The antiangiogenic agent apatinib has been shown to clinically improve responses to immune checkpoint inhibitors in several cancer types. Patients with N3 nasopharyngeal carcinoma have a high risk of distant metastasis, however, if the addition of immunotherapy to standard treatment could improve efficacy is unclear. In this phase II clinical trial (ChiCTR2000032317), 49 patients with stage TanyN3M0 nasopharyngeal carcinoma were enrolled and received the combination of three cycles of induction chemotherapy, camrelizumab and apatinib followed by chemoradiotherapy. Here we report on the primary outcome of distant metastasis-free survival and secondary end points of objective response rate, failure-free survival, locoregional recurrence-free survival, overall survival and toxicity profile. After induction therapy, all patients had objective response, including 13 patients (26.5%) with complete response. After a median follow-up of 28.7 months, the primary endpoint of 1-year distant metastasis-free survival was met for the cohort (1-year DMFS rate: 98%). Grade≥3 toxicity appeared in 32 (65.3%) patients, with the most common being mucositis (14[28.6%]) and nausea/vomiting (9[18.4%]). In this work, camrelizumab and apatinib in combination with induction chemotherapy show promising distant metastasis control with acceptable safety profile in patients with stage TanyN3M0 nasopharyngeal carcinoma.

Guided isolation of secondary metabolites from Nectria sp. MHHJ-3 by molecular network strategy

The fungus Nectria sp. MHHJ-3 was isolated from Illigera rhodantha. A molecular networking-guided the secondary metabolites investigation of Nectria sp. MHHJ-3 led to the isolation of ten metabolites (1-10), including two new naphthalenone derivatives, nectrianaphthalenones A (1) and B (2), and two new steroids, nectriasteroids A (3) and B (4). Their structures were elucidated by extensive spectroscopic analysis including the HRESIMS, 1D/2D NMR and electronic circular dichroism (ECD) spectra. A plausible biosynthetic pathway for 1-2 was proposed. Compounds 1 and 2 exhibited moderate acetylcholinesterase (AChE) inhibitory activities. Compounds 3 and 4 showed significant cytotoxic activity against selected tumor cells. Particularly, compound 3 exhibited the strongest activity against A549 cells with an IC50 value of 13.73 ± 0.03 μM, which was at the same grade with that of positive control cisplatin.

Structurally diverse terpenoids from Elephantopus scaber L. and their acetylcholinesterase inhibitory activities

Three undescribed compounds elephantopuscabers A-C, along with one previously reported compound spirowallichiione, were isolated from Elephantopus scaber L. Their structures were determined via extensive NMR spectroscopic analysis, quantum chemical calculations, and single-crystal X-ray diffraction crystallography. A plausible biosynthetic pathway for spirowallichiione was proposed. All the isolated compounds were tested for their acetylcholinesterase inhibitory activities. Among them, elephantopuscaber B and C displayed promising inhibitory activities against AChE, and the binding sites were predicted by molecular docking.

Rapid screening of diarylpentanoids from Daphne bholua

Fractionation motivated by biological activity screening and NMR characteristic signals analysis led to the isolation of seventeen diarylpentanoids from the whole plant of Daphne bholua Buch.-Ham. ex D. Don, among which nine compounds were undescribed. Their structures and stereochemistry were determined by comprehensive spectroscopic data, J-based configurational analysis, and quantum chemical calculations. The inhibitory potentials of all isolates against acetylcholinesterase were evaluated in vitro and in silico.

Isolation of cytotoxic daphnane-type and tigliane-type diterpenoids from Daphne genkwa using MetGem software

To discover diterpenoids that naturally possess chemical weapons against cancer, the biological and chemical diversity of the flower buds of Daphne genkwa Sieb. et Zucc was investigated. Guided by LC-MS/MS...

Quassinoids: Phytochemistry and antitumor prospect

Quassinoids, originating from the oxidative degradation of tetracyclic tirucallane triterpene, are a diverse class of secondary metabolites identifying from nature mostly in Simaroubaceae family. The crucial pharmacological activities and structural complexity of quassinoids have long fascinated scientists due to their medicinal uses, infamous toxicity, and unique biosynthesis. In the past few decades, 482 quassinoids, assigned to 6 skeletons, have been isolated and identified from plants. The names, classes, molecular formula, and plant sources of these secondary metabolites are collated here. This review will be a detailed update of the naturally occurring quassinoids reported from the plant kingdom, providing an in-depth discussion of their diversity, antitumor activities, structure-activity relationship.

Modified lanostane-type triterpenoids with neuroprotective effects from the fungus Inonotus obliquus

Six undescribed lanostane triterpenoids (1-6), together with three known compounds (7-9) were isolated from Inonotus obliquus. Compounds 3-5 are the rare natural compounds featuring a 4,5-seco-lanostane core with a 5,7,9-trien-21,24-cyclopentane moiety. The structure elucidation of the compounds was conducted by spectroscopic techniques and the ECD method. The absolute configuration of compound 1 was confirmed by single-crystal X-ray diffraction analysis. All isolated compounds were assayed for their neuroprotective activity against H₂O₂-induced cell injury using human neuroblastoma SH-SY5Y cells. Compound 9 exhibited the most potent neuroprotective activity and the flow cytometry analysis indicated that 9 could protect SH-SY5Y cells from oxidative damage by inhibiting cell apoptosis.

Germacranolides from Elephantopus scaber L. and their cytotoxic activities

Seven undescribed germacranolides, named as scabertopinolide A-G were obtained from whole herbs of Elephantopus scaber L. The determination of their structures was conducted via comprehensive spectroscopic analyses combined with experimental electronic circular dichroism (ECD) spectroscopic data and quantum mechanical ECD calculations. The absolute configuration of scabertopinolide A was determined by X-ray crystallography data analysis. The cytotoxicity of all compounds was evaluated against three human cancer cell lines HepG2, Hep3B (human hepatocellular carcinoma cell lines), and MCF-7 (human breast adenocarcinoma cell line). Scabertopinolide G exhibited the most significant cytotoxic activities against the three cancer cell lines with IC₅₀ values between 7.0 and 10.3 μM. Furthermore, flow cytometry analysis has suggested that scabertopinolide G may cause death of cancer cells through apoptosis induction.

Dihydroagarofuran sesquiterpenoid derivatives from the leaves of Tripterygium wilfordii with potential neuroprotective effects against H2O2-induced SH-SY5Y cell injuries

In this study, eight undescribed sesquiterpenoid esters and four known analogues were isolated and their absolute configurations were determined by ECD calculations and single-crystal X-ray diffraction analysis.

[The effect of air test and methylene blue perfusion test on detecting the quality of anastomosis during laparoscopic rectal cancer excision (Dixon)]

Objective: To investigate the feasibility and safety of air test (AT) and methylene blue perfusion test (MBPT) to detect the quality of the anastomosis in laparoscopic rectal cancer excision (Dixon), and compare the two approaches. Methods: AT is performed by filling the pelvis with saline solution and insufflating the rectum with air through a size 22 G balloon catheter (Foley). MBPT is carried out by surrounding clean sponges around anastomosis and injecting methylene blue solution into the rectum as like as AT. The balloon catheter connected manometer,ensuring the pressure in rectum can reach 40 cmH(2)O during AT and MBPT. The presence of air bubbles and overt blue-stained spillage indicated anastomotic leaks which are were resolved during surgery. All 28 patients undergoing laparoscopic rectal excision received both AT and MBPT intraoperatively in a randomized fashion. The integrity of the anastomosis, postoperative vital signs, blood examination, drainage and postoperative imaging were analyzed. Results: All 28 patients received both tests successfully with no adverse event. MBPT Level 1 was detected in 15 cases, level 2 in 8 cases, level 3 in 5 cases. No MBPT level 4 was observed. AT level 1 was detected in 22 cases, level 2 in 5 cases, level 3 in 1 cases. No AT level 4 was founded. Three cases were diagnosed with postoperative anastomotic leakage (3/28, 10.71%), of which 2 cases were Grade B [definition and grading proposed by the international study group of rectal cancer (ISREC) in 2010]. One case was Grade C. The positive rate of MBPT was superior to AT (the McNemar testing, P<0.01). Conclusions: The two intraoperative tests are both technically feasible and safe. Compared to AT, MBPT has the advantage of localizing the leak site with a higher positive accuracy, and represents a promising standardized approach for intraoperative test of the anastomosis quality. Intraoperative repair is absolutely helpful for the level 3 and 4 intraoperative tests.

[Clinical effects of different methods of the proximal fusion for long segmental lumbar vertebrae fusion in treatment of degenerative lumbar scoliosis]

Objective: To explored the clinical effects of different methods of the proximal fusion for long segmental lumbar vertebrae fusion in treatment of degenerative lumbar scoliosis(DLS). Methods: From January 2007 to March 2014 fifty-five cases of DLS treated by the posterior proximal fusion of long segmental lumbar vertebrae fusion were analyzed in Department of Orthopaedics, Shanghai general Hospital of Nanjing Medical University (35)HuaiAn The First Hospital Affiliated to Nanjing Medical University(20). According to various upper instrumented vertebra(UIV) the patients were divided into Group A(upper horizontal vertebra, UHV, n=17), Group B (upper natural vertebra, UNV n=18 ), and Group C(upper end vertebra, UEV, n=20). The VAS, ODI, spinal balance parameters and postoperative complications in each group were assessed. Results: Except for 1 case death of serious lung infection in early postoperative, 54 cases were received 2-4 years follow-up. No statistical differences in improvements and fusion rates were found among 3 groups (P>0.05). The improvements of the coronal Cobb's angle in the A group were significantly more than the C group (75.8%±12.8%, 69.6%±11.8%, 63.4%±15.3%, P<0.05). The incidences of early postoperative complications in A group were the highest, next in B group, and lowest C group (52.9%, 22.0%, 15.0%, P<0.05). The incidences of proximal ASD in the C group were significantly more than the A group (12.5%, 22.2%, 50.0%, P=0.045). Conclusion: UHV, UNV and UEV had similar clinical outcomes for treatment of degenerative lumbar scoliosis in short term. Correction of the coronal deformity of UHV was superior to UEV. UEV was beneficial to reduce early complications, but more likely to happen proximal adjacent segment degeneration in the long run.

[Effects of microRNA-379-5p on proliferation, migration and invasion of hepatocellular carcinoma cell line]

OBJECTIVE

To investigate the effects of microRNA-379-5p (miR-379-5p) on proliferation, migration and invasion of hepatocellular carcinoma (HCC) cells.

METHODS

Human HCC cell line HepG2 was infected with lentivirus carrying miR-379-5p (miR-379-5p group) or lentivirus carrying negative control sequences (negative control group). The untreated HepG2 cells represented blank control group. Cell proliferation was determined by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazoliumbromide (MTT) assays. Cell migration and invasion were assessed by Transwell assays. The mRNA and protein expressions of matrix metalloproteinase-2 (MMP-2) and MMP-9 were analyzed by real-time quantitative polymerase chain reaction and Western blot, respectively.

RESULTS

Compared with negative control group and blank control group, cell migration and invasion was significantly inhibited in miR-379-5p group (P<0.05). However, there was no significant difference in cell proliferation among the three groups (P>0.05). Furthermore, the mRNA and protein levels of MMP-2 and MMP-9 in miR-379-5p group were significantly lower than that in negative control group and blank control group (P<0.05).

CONCLUSION

miR-379-5p can suppress migration and invasion of HCC cell lines, which may be achieved by inhibiting MMP-2 and MMP-9 expressions.

Effects of minimally invasive percutaneous and trans-spatium intermuscular short-segment pedicle instrumentation on thoracolumbar mono-segmental vertebral fractures without neurological compromise

OBJECTIVE

To compare the outcomes of minimally invasive percutaneous short-segment pedicle instrumentation (SSPI) with that of trans-spatium intermuscular SSPI on thoracolumbar mono-segmental vertebral fracture without neurological compromise.

METHODS

A total of 39 patients with thoracolumbar mono-segmental vertebral fracture without neurological deficit receiving treatment between January 2009 and July 2011 were enrolled. Percutaneous SSPI was performed for 18 patients (the percutaneous group), and trans-spatium intermuscular SSPI was performed for 21 patients (the trans-spatium intermuscular group). Peroperative indices, intraoperative radiation exposure time, postoperative and follow-up lumbodorsal pain, function scores, and radiological data were compared.

RESULTS

The percutaneous group had significantly less intraoperative blood loss and less severe postoperative pains, but suffered significantly longer fluoroscopy time and higher hospitalization costs compared with the trans-spatium intermuscular group. No significant difference was observed in operating time. All patients were followed up for 17.3 ± 9.2 months (ranging from 5 to 35 months). No significant differences were observed between the two groups in terms of postoperative relative vertebral height (RVH) and regional kyphotic angle (RKA), as well as last follow-up RVH, RKA, lumbodorsal pain, and Oswestry disability index.

CONCLUSION

Percutaneous SSPI has the virtues of less intraoperative blood loss and less severe pains in the treatment of thoracolumbar mono-segmental vertebral fracture without neurological deficit. When compared with trans-spatium intermuscular SSPI, it results in longer intraoperative radiation exposure time and a higher surgery cost. To us, percutaneous SSPI has no advantage over trans-spatium intermuscular SSPI in therapeutic outcomes.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Survival of conditionally immortalized hepatocytes in the spleen of syngeneic rats

BACKGROUND

Hepatocyte transplantation has been shown to be effective in the treatment of liver failure; however, the shortage of donor organs limits its clinical application. Several reports have suggested that conditionally immortalized hepatocytes (CIH) could be an alternative to primary hepatocytes. However, CIH are known to undergo apoptosis in vitro at a non-permissive temperature, which is similar to body temperature.

METHODS

To investigate the duration of survival and in vivo apoptosis of CIH in the syngeneic host, the L2A2 cells (a kind of CIH) that were established from hepatocytes of a Lewis rat with a gene for a temperature-sensitive Simian Virus 40 (SV40) large T antigen were transplanted into the spleen. Cells were isolated from the spleen that was removed periodically up to 6 months, and used to detect the presence of the L2A2 cells among them with the selective culture for CIH and T-antigen PCR. In situ apoptosis of L2A2 cells was also examined. In order to improve the survival of transplanted L2A2 cells in the host, a group of rats were partially hepatectomized 1 day before transplantation was performed.

RESULTS

The L2A2 cells secreted albumin at a rate of 1.17 +/- 0.18 microg/24 h per 10(6) cells in vitro. After transplantation, L2A2 cell colonies and PCR amplification bands appeared up to 14 and 7 days, respectively, but this duration was not prolonged by a partial hepatectomy. The spleen showed a large number of hepatocytes that were in the process of dying on the 5th day, and only a number of ghost hepatocytes were present on the 7th day of transplantation. No tumors were found during the 6-month observation period.

CONCLUSIONS

Conditionally immortalized hepatocytes can survive in the spleen for a limited period, in spite of the growth stimulation, most likely because they undergo apoptosis in vivo as well as in vitro at a non-permissive temperature. These data suggest that the use of these cells in hepatocyte transplantation be limited to temporary hepatic support.

The incidence and clinical characteristics of symptomatic propylthiouracil-induced hepatic injury in patients with hyperthyroidism: a single-center retrospective study

OBJECTIVES

Although symptomatic propylthiouracil (PTU)-induced hepatic injury is known to be rare, there have been few reports about its exact incidence in patients with hyperthyroidism. We tried to evaluate its incidence in a single center and its clinical course.

METHODS

Medical records of 912 hyperthyroid patients who had been diagnosed between March 1990 and December 1998 were reviewed about clinical characteristics, management, and laboratory findings. Symptomatic PTU-induced hepatic injury was defined as the development of jaundice or hepatitis symptoms with at least a 3-times elevation of liver function tests (LFT) without other causes.

RESULTS

Four hundred ninety-seven patients (age 42.6 +/- 10.7 yr, male/female 140/357) were included. Clinically overt hepatitis developed in six patients (1.2%; age, 43.7 +/- 14.8 yr; male:female ratio, 3:3) between 12 and 49 days after PTU administration. Jaundice and itching developed in five patients, fever in two, rash in two, and arthralgia in one. Bilirubin, ALT, and ALP increased in five, four, and six patients, respectively (293 +/- 288 micromol/L, 143 +/- 111 U/L, and 265 +/- 81 U/L; normal, < 117 U/L). The type of hepatic injury was cholestatic in three, hepatocellular in one, and mixed in two patients. None resulted from viral hepatitis. There were no statistical differences in age, sex, PTU dose, or T4 and T3 levels at initial diagnosis between patients with and without hepatic injury. LFT normalized in all patients between 16 and 145 (72.8 +/- 46.4) days after the PTU withdrawal.

CONCLUSIONS

Symptomatic hepatic injury develops usually within the first few months of PTU administration with rare frequency, but its clinical course is relatively benign once the drug is withdrawn. However, it may be difficult to predict its development, so all patients should be monitored for rise in LFTs at regular intervals, especially during the early period.

Autoimmune hepatitis in a patient with myasthenia gravis and thymoma--a report on the first case in Korea

Myasthenia gravis is an autoimmune disease that results from an antibody-mediated reaction and occurs with thymoma in 15% of patients. It is very rarely associated with autoimmune hepatitis. Four cases of myasthenia gravis with autoimmune hepatitis have been reported in the world. We recently experienced a case of 30-year-old man with myasthenia gravis associated with thymoma and autoimmune hepatitis. This condition is the first case that has not been reported previously in Korea. We report this rare condition along with a brief review of the literature.

Decreased trabecular bone mineral density in newly diagnosed inflammatory bowel disease patients in Korea

BACKGROUND

Decreased bone mineral density (BMD) is common in Western patients with inflammatory bowel disease (IBD). However, BMD has never been studied in Asia where the demographic and socio-economic status are different from the West. The aim of this study was to investigate the prevalence and mechanisms of osteopenia in newly diagnosed Korean patients with IBD.

METHODS

We studied 14 patients with Crohn's disease (CD) and 25 patients with ulcerative colitis (UC), all of whom had never been treated with corticosteroids. Bone mineral density was measured in the lumbar spine and the femoral neck by dual energy X-ray absorptiometry. Biochemical parameters including serum osteocalcin, parathyroid hormone, plasma inactive and active vitamin D, and urinary deoxypyridinoline were measured.

RESULTS

The BMD Z score at the lumbar spine was lower both in CD and in UC patients, but there was no significant difference between the two groups. There was no significant difference in nutritional status or biochemical parameters of bone metabolism between patients with a normal BMD and those with a decreased BMD.

CONCLUSIONS

Low BMD at the lumbar spine is common in newly diagnosed Korean patients with IBD, a result which is similar to Western studies. The mechanism for low bone mass remains undetermined; however, nutritional status and hormonal parameters of bone metabolism, and ethnic differences are not likely to be an important factor in the pathogenesis of this bone loss.

Dedifferentiation of conditionally immortalized hepatocytes with long-term in vitro passage

The rat hepatocytes were immortalized using a temperature-sensitive mutant of SV40 large T antigen (tsT) to develop as a possible substitute for primary hepatocytes. Four rat hepatocyte lines that have been developed and maintained more than passage 50, were characterized for their cellular morphology, T antigen and p53 expression, chromosomes, liver-specific differentiation, telomerase activity and anchorage independent growth. All of four cell lines showed a typical epithelial cell morphology, but the population-doubling time became short with passage: 18 to 60%. T antigen expression was increased with passage about 3 to 65 times at permissive temperature but decreased significantly at non-permissive temperature. The expression level of p53 unchanged during passages was also decreased at non-permissive temperature. The distribution of chromosome number changed somewhat with passage. The production levels of albumin and urea in four cell lines were 2.4 to 13.0% and 7.5 to 19.9% of those produced in primary hepatocytes, respectively and were decreased to an undetectable level with passage. Telomerase activity was increased 10 fold following immortalization of cells, but anchorage independent growth of cells did not develop. These results indicate that conditionally immortalized hepatocytes become dedifferentiated with in vitro passage, which may be caused by marked chromosomal damages that occur with compulsive and continuous replications by the increment of T antigen content with passage and its sequential inhibition of p53 function.

Algebraic Description of Anharmonic Stretching Vibrations

A U(2) algebraic model is presented to describe stretching vibrations of XYn (n = 2, 3, and 4) systems, where anharmonic interactions between the bond modes are considered. This model in a limit corresponds to an anharmonically coupled local-mode model. As an example, the model for a molecule XY4 is applied to recently observed spectra of methane in both gas and liquid phases, and the results obtained are in good agreement with the experiments. Copyright 1999 Academic Press.

Mutational abrogation of the PTEN/MMAC1 gene in gastrointestinal polyps in patients with Cowden disease

BACKGROUND & AIMS

To understand the molecular etiology of Cowden disease-associated gastrointestinal polyps, we analyzed the mutational status of PTEN/MMAC1, a recently identified Cowden disease gene located at 10q23, in gastric hamartomas, colonic adenoma, and juvenile polyps of 3 patients with Cowden disease.

METHODS

Messenger RNA expression, gene deletion, and sequence alteration of PTEN/MMAC1 were evaluated by quantitative polymerease chain reaction (PCR), PCR-single-strand conformation polymorphism, and sequencing analysis.

RESULTS

Germline missense mutation at codon 289 (AAA to GAA, Lys to Glu) and deletion of the wild-type allele were detected in the polyps of 2 patients with Cowden disease in the same family. Germline allelic deletion and transcriptional silencing of the remaining allele, probably caused by abnormal methylation, were also observed in a gastric hamartoma of 1 patient.

CONCLUSIONS

The germline mutation and alteration of the remaining allele observed in this study strongly support that PTEN/MMAC1 functions as a tumor suppressor in Cowden disease. This study is the first to show that the mutational abrogation of PTEN/MMAC1 plays a causal role in the genesis of gastrointestinal polyps in Cowden disease, providing molecular genetic evidence that colonic adenoma, juvenile polyp, and gastric hamartoma could be included in the manifestations of Cowden disease.

Interferon alpha therapy in patients with chronic type C hepatitis: changes of serum ALT, anti-HCV & HCV-RNA

BACKGROUND

After the discovery of type C hepatitis virus, the studies on this virus are extensively progressing. The treatment of this viral infection is also widely progressing. Among many agents, recombinant interferon alpha therapy is generally accepted as an effective single agent. To evaluate the efficacy of interferon and to observe the changes of serum aminotransferase (ALT), antibody to hepatitis C virus (anti-HCV) and HCV ribonucleic acid (HCV-RNA), we treated 10 patients with chronic type C hepatitis for 6 months.

METHODS

Patients were randomly divided into 2 groups: 5 patients in group A received interferon and the other 5 in group B received no therapy. Interferon was administered at a dose of 3 million units (MU) daily for the first month and thrice weekly for the following 5 months, and followed up for 2 years.

RESULTS

In group A, serum ALT returned to normal in 4: 3, starting at the first month and one at the 3rd month of therapy and maintained normal throughout the follow-up period. In contrast, serum ALT level persistently fluctuated in 4 patients in group B. In one patient, serum ALT returned to normal one and a half years later. Regardless of therapy, serum anti-HCV titer remained unchanged in all patients. However, HCV-RNA, using polymerized chain reaction (PCR), became undetectable in all responded patients and in one untreated patient whose serum ALT returned to normal spontaneously.

CONCLUSION

This study suggested that interferon alpha therapy in patients with chronic type C hepatitis may be clinically effective. Our study also indicated that the detection of HCV-RNA by PCR is useful to predict the prognosis of chronic type C hepatitis.

Arterialized capillary blood gases and acid-base studies in normal individuals from 29 days to 24 years of age

Studies of arterialized capillary blood gases and acid-base values were performed on 712 normal persons who were between the ages of 29 days and 24 years. The results were divided for clinical use into six groups by age; linear regression lines were constructed for better understanding of the development of blood gas levels and the acid-base balance. The blood pH essentially remained unchanged throughout the study period. The oxygen and carbon dioxide pressures, base excess of extracellular fluid, and buffer base and bicarbonate levels are lower in infants than in children and adults; adult values are reached at approximately 7 to 12 years of age. The probable explanation for the lower values in infants is discussed. The effects of crying on the composition of blood gases are mentioned.