Comprehensive Analysis of the Effect of Probiotic Intake by the Mother on Human Breast Milk and Infant Fecal Microbiota

BackgroundHuman breast milk (HBM) contains optimal nutrients for infant growth. Probiotics are used to prevent disease and, when taken by the mother, they may affect infant microbiome as well as HBM. However, few studies have specifically investigated the effect of probiotic intake by the mother on HBM and infant microbiota at genus/species level. Therefore, we present a comprehensive analysis of paired HBM and infant feces (IF) microbiome samples before and after probiotic intake by HBM-producing mothers.MethodsLactating mothers were administered with Lactobacillus rhamnosus (n = 9) or Saccharomyces boulardii capsules (n = 9), for 2 months; or no probiotic (n = 7). Paired HBM and IF samples were collected before and after treatment and analyzed by next-generation sequencing.ResultsForty-three HBM and 49 IF samples were collected and sequenced. Overall, in 43 HBM samples, 1,190 microbial species belonging to 684 genera, 245 families, 117 orders, and 56 classes were detected. In 49 IF samples, 372 microbial species belonging to 195 genera, 79 families, 42 orders, and 18 classes were identified. Eight of 20 most abundant genera in both HBM and IF samples overlapped: Streptococcus (14.42%), Lactobacillus, Staphylococcus, and Veillonella, which were highly abundant in the HBM samples; and Bifidobacterium (27.397%), Bacteroides, and Faecalibacterium, which were highly abundant in the IF samples. Several major bacterial genera and species were detected in the HBM and IF samples after probiotic treatment, illustrating complex changes in the microbiomes upon treatment.ConclusionThis is the first Korean microbiome study in which the effect of different probiotic intake by the mother on the microbiota in HBM and IF samples was investigated. This study provides a cornerstone to further the understanding of the effect of probiotics on the mother and infant microbiomes.     

Identification of Activin A and Follistatin in Human Milk

Activin A is a dimeric protein member of the transforming growth factor- &#103 (TGF- &#103 ) family: it is synthesized by a variety of organs and follistatin is an activin-binding protein. A sensitive and specific assays for bioactive dimeric activin A and follistatin have recently allowed to measure these proteins in blood and other biological fluids, giving a new insights into their possible physiological role. Since human breast is able to produce activin A, the aim of the present study was to evaluate whether it and follistatin are measurable in breast milk of women during lactation. Concentrations of activin A and follistatin were measured in milk samples collected at 3, 5 and 30 days after delivery by using specific and sensitive two-site ELISAs. For the first time the presence of immunoreactive activin A and follistatin in human milk has been shown; no significant different concentration between the third and the fifth day after delivery was found. Furthermore, no difference of activin A and follistatin concentration between the whole and the skim milk or between spontaneous delivery and cesarean section was found. Milk activin A and follistatin concentrations after 1 month of lactation were significantly decreased (P <0.01). Activin A and follistatin are present in human milk in high concentrations in the first week of lactation, while decrease after a month suggesting a possible role as growth factors in human milk.     

Serial Long-Term Growth and Neurodevelopment of Very-Low-Birth-Weight Infants: 2022 Update on the Korean Neonatal Network

BackgroundWe aimed to evaluate the long-term growth and neurodevelopmental outcomes of very-low-birth-weight infants (VLBWIs, birth weight < 1,500 g) born between 2013, the establishment of the Korean Neonatal Network (KNN), and 2018, both at 18–24 months of corrected age and three years of age, using a nationwide large cohort, and to evaluate whether these outcomes have improved over time since 2013.MethodsThis study used data from the annual reports of the KNN for 18–24 months of corrected age (follow-up 1) and three years of age (follow-up 2). Follow-up 1 data were collected from 10,065 eligible VLBWIs born between January 1, 2013, and December 31, 2018. Follow-up 2 data were collected from 8,156 eligible VLBWIs born between January 1, 2013, and December 31, 2017.ResultsThe overall follow-up rates of VLBWIs at follow-ups 1 and 2 were 74.6% (7,512/10,065) and 57.7% (4,702/8,156), respectively. The overall mortality rate between discharge from the neonatal intensive care unit and follow-up 1 was 1% (104/10,065). The overall mortality rate between follow-ups 1 and 2 was 0.049% (4/8,156). Growth restrictions decreased over time, especially weight growth restrictions, which significantly decreased according to era (17% in infants born in 2013–2014 and 13% in infants born in 2017–2018). Fewer infants were re-hospitalized and required rehabilitative support according to era at follow-up 1. More infants had language developmental delays and required language support according to era, both at follow-ups 1 and 2. The incidence of cerebral palsy has significantly decreased over time, from 6% in infants born in 2013–2014 to 4% in infants born in 2017–2018 at follow-up 1, and from 8% in infants born in 2013–2014 to 5% in infants born in 2017 at follow-up 2.ConclusionLong-term outcomes of VLBWIs regarding weight growth and cerebral palsy, the most common motor disability in childhood, have improved serially according to era since 2013. However, the rate of infants with language delays requiring language support has increased according to era. Further studies are required on the increased trends of language delay and language support while improving motor outcomes.     

Separation of Broad Spectrum Anti-LPS IgA From Human Milk Using LPS Chitosan Affinity Chromatography

An affinity chromatography technique was developed for separation of broad spectrum antilipopolysaccharide (LPS) IgA antibodies from human milk. The affinity column was prepared by immobilizing LPS from Escherichia coli O111:B4 on to porous chitosan beads using glutaraldehyde activation. IgA separated from human milk using a Jacalin column was cycled through the LPS-chitosan column at a slow rate. Bound IgA was eluted with glycineHCl, pH 2.6, and presence of IgA in the eluate was confirmed by radial immunodiffusion (RID) and by visualization on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Column binding capacity was 0.22 mg of LPS-specific IgA ml^-1. The stability of immobilized LPS was confirmed upon repeated uses of the column with negligible leaching of the ligand. The affinity purified anti-LPS IgA accounted for 12.3% of Jacalin purified IgA and was found to cross-react highly with E. coli O128:B12, and Klebsiella pneumoniae using LPS-ELISA, demonstrating the use of this technique for purification of broad spectrum, cross reactive immunoglobulins. There is a great potential for application of this technique in preparation of antibodies for prevention of enteric gram-negative infections in high risk individuals. The low cost column material used (chitosan beads) makes large scale utilization of this technique more practical.     

Serial Short-Term Outcomes of Very-Low-Birth-Weight Infants in the Korean Neonatal Network From 2013 to 2020

BackgroundWe aimed to determine the current survival rate and short-term outcomes of very-low-birth-weight infants (VLBWIs) in Korea, as well as whether the survival rate and short-term outcomes have improved over time since 2013, which was when the Korean Neonatal Network (KNN) was launched.MethodsThis study used data from the annual reports of the KNN from 2013 to 2020. A total of 16,351 VLBWIs born at gestational age (GA) ≥ 22 weeks between January 1, 2013, and December 31, 2020, and who were registered in the KNN were enrolled. Serial outcomes were analyzed according to era (2013–14, 2015–16, 2017–18, and 2019–20).ResultsMore mothers delivered by cesarean section, had diabetes or hypertension during their pregnancy, and received antenatal steroids when analyzed by era. Fewer infants were intubated at birth and had air leaks when analyzed by era. The overall survival rate of VLBWIs between 2013 and 2020 was 87%. The rate of respiratory distress syndrome was 77% and that of bronchopulmonary dysplasia was 32% between 2013 and 2020. The rates of intraventricular hemorrhage (grade ≥ 3), periventricular leukomalacia, and sepsis decreased over time. The survival rate of infants with a GA of 26 weeks has improved serially according to era.ConclusionSince the launch of the KNN in 2013, the survival rates of infants with GA 26 weeks and short-term outcomes have improved, which implies a quality improvement in antenatal and delivery room care. Further studies on the long-term neurodevelopmental outcomes of these KNN registrants are warranted.     

The Effect of Mare's Milk Consumption on Functional Elements of Phagocytosis of Human Neutrophil Granulocytes From Healthy Volunteers

We investigated functional parameters of phagocytosis in 18 healthy volunteers drinking 250 mL of mare's milk, deep-frozen (FMM) or lyophilized (LMM), or cow's milk (CM) daily for three weeks. Blood was taken before, weekly during, and one week after intervention. Chemotaxis of isolated polymorphonuclear leukocytes (PMN) was investigated by a micropore filter assay, migration was determined fluorimetrically. The activity of phagocytosis and respiratory burst of PMN in whole blood was analysed with Phago- and Bursttest ® by flow cytometry. Contrary to phagocytosis activity, chemotactic index (CI) and burst activity diminished significantly in the group FMM. One week after intervention, CI rose tendentiously, burst activity significantly. In conclusion, immunostimulating effects ascribed to mare's milk consumption could not be observed in healthy volunteers, at least concerning phagocytosis. Our results suggest that drinking FMM modulates inflammation processes by decreasing chemotaxis and respiratory burst, which might be favourable for giving relief to diseases with recurrent inflammation.     

Survey on the Status of Breastfeeding in Korean Medical Institution Workers

BackgroundHuman breast milk is essential and provides irreplaceable nutrients for early humans. However, breastfeeding is not easy for various reasons in medical institution environments. Therefore, in order to improve the breastfeeding environment, we investigated the difficult reality of breastfeeding through questionnaire responses from medical institution workers.MethodsA survey was conducted among 179 medical institution workers with experience in childbirth within the last five years. The survey results of 175 people were analyzed, with incoherent answers excluded.ResultsOf the 175 people surveyed, a total of 108 people (61.7%) worked during the day, and 33 people (18.9%) worked in three shifts. Among 133 mothers who stayed with their babies in the same nursing room, 111 (93.3%) kept breastfeeding for more than a month, but among those who stayed apart, only 10 (71.4%) continued breastfeeding for more than a month (P = 0.024). Ninety-five (88.0%) of daytime workers, 32 (94.1%) two-shift workers, and 33 (100%) three-shift workers continued breastfeeding for more than a month (P = 0.026). Workers in general hospitals tended to breastfeed for significantly longer than those that worked in tertiary hospitals (P = 0.003). A difference was also noted between occupation categories (P = 0.019), but a more significant difference was found in the comparison between nurses and doctors (P = 0.012). Longer breastfeeding periods were noted when mothers worked three shifts (P = 0.037). Depending on the period planned for breastfeeding prior to childbirth, the actual breastfeeding maintenance period after birth showed a significant difference (P = 0.002). Of 112 mothers who responded to the question regarding difficulties in breastfeeding after returning to work, 87 (77.7%) mentioned a lack of time caused by being busy at work, 82 (73.2%) mentioned the need for places and appropriate circumstances.ConclusionIn medical institutions, it is recommended that environmental improvements in medical institutions, the implementation of supporting policies, and the provision of specialized education on breastfeeding are necessary to promote breastfeeding.     

Economic Burden and Epidemiology of Pneumonia in Korean Adults Aged over 50 Years

This study was performed to estimate the direct medical costs and epidemiology of pneumonia in adults of Korea. We conducted a multi-center, retrospective, observational study and collected data targeting for community-acquired pneumonia patients ( ≥ 50 yr) from 11 hospitals. Costs attributable to the treatment of pneumonia were estimated by reviewing resource utilization and epidemiology data (distribution of pathogen, hospital length of stay, overall outcome) were also collected. A total 693 patients were included; average 70.1 ( ± 10.5) aged, 57.3% male and average 1.16 CURB-65 (confusion, blood urea nitrogen, respiratory rate, blood pressure, age > 65 yr) scored. The pathogen was identified in the 32.9% (228 patients); Streptococcus pneumoniae accounted for 22.4% (51 patients) of identified pathogens. The hospital mortality was 3.2% (especially, for S. pneumoniae was 5.9%) and average length of stay was 9 days. The mean total cost for the treatment of pneumonia was US dollar (USD) 1,782 (SD: USD 1,501). Compared to the cost of all caused pneumonia, that of pneumococcal pneumonia was higher, USD 2,049 ( ± USD 1,919), but not statistically significant. Charge of hospitalization accounted the greatest part of total medical costs. The economic burden of pneumonia was high in Korea, and the prevention of pneumonia should be considered as effective strategy.     

Immunological IgE Cross-Reactions of Bovine and Human α-Lactalbumins in Cow's Milk Allergic Patients

Despite great homology with the equivalent human protein, bovine α-lactalbumin (B α-La), a major component of whey, has been identified as a major milk allergen. The aim of this study was to investigate the relationship between structure and IgE binding capacity in α-Las: (1) the importance of three-dimensional structure using native vs disulfide bridgereduced B α-La; and (2) the incidence of amino acid sequence divergence on specific IgE cross-reactivity to human vs bovine α-La. Purified native, reduced and S-carboxymethylated B α-La and human α-La (H alpha-LA) were prepared. Specific IgE of 20 sera from patients with clinically recognized cow's milk protein allergy and positive RAST tests to B α-La were measured in original direct and competitive ELISA inhibition tests. All sera containing specific anti-native B α-La IgE also reacted with denatured protein, but the IgE levels were generally lower, showing that three-dimensional structure is an important feature in B α-La allergenicity but that sequential epitopes are also exposed after protein denaturation. Despite lower IgE levels, all sera also gave significant IgE responses to H α-La. Competitive ELISA inhibition confirmed results obtained by direct ELISA. The demonstrated IgE cross-reactivity between B α-LA and H α-La could be related to the high degree of sequence homology between the two proteins but did not prove to have a clinical significance. However, it is of great interest for a study of the relationship between structure, IgE binding capacity and allergenicity in alpha-Las.     

Recent trends in neonatal mortality in very low birth weight Korean infants: in comparison with Japan and the USA

With regard to the outcome of intensive neonatal care, one of the most important concerns in neonatology is the mortality rate of very low birth weight infants (VLBWI; birth weight < 1,500 g) and extremely low birth weight infants (ELBWI; birth weight < 1,000 g). The present study was conducted to analyze and compare the mortality of VLBWI and ELBWI and neonatal care among Korean, Japanese, and American newborns. In Korea, the survival rates of VLBWI have increased significantly; they were 31.8% in the early 1960s, 65.8% in the early 1990s, 77.5% in 2002, 84.7% in 2007, and 85.7% in 2009. The survival rates of ELBWI have also increased; they were 8.2% in the early 1960s, 37.4% in the early 1990s, 56.1% in 2002, 67.7% in 2007, and 71.8% in 2009. The survival rates of VLBWI and ELBWI have significantly improved over the past 50 yr in Korea. However, the Korean survival rates of VLBWI and ELBWI are still lower than for similar groups in Japan and the USA. To achieve better outcomes that reach the level of these countries, the organization of perinatal care centers, nationwide neonatal perinatal research networks, and regionalization are needed in Korea.     

Validity of the Ages and Stages Questionnaires in Korean Compared to Bayley Scales of Infant Development-II for Screening Preterm Infants at Corrected Age of 18-24 Months for Neurodevelopmental Delay

This study aimed to evaluate the validity of the ages and stages questionnaire in Korean (ASQ 1st edition, Korean Questionnaires, Seoul Community Rehabilitation Center, 2000) for premature infants. The study population consisted of 90 premature infants born between January 1, 2005, and December 31, 2011, who were tested using the ASQ (Korean) and Bayley Scales of Infant Development (BSID) (II) at a corrected age of 18-24 months. The validity of the ASQ (Korean) using cut-off values set at < -2 SD was examined by comparing it to the BSID (II) components, namely, the mental developmental index (MDI) or psychomotor developmental index (PDI), which were both set at < 85. The calculation of the sensitivities, specificities, positive predictive values, and negative predictive values of the ASQ (Korean) components revealed that they detected infants with neurodevelopmental delay with low sensitivity and positive predictive values, however, the communication domain showed moderate correlations with MDI. The failure in more than one domain of the ASQ (Korean) was significantly correlated with the failure in MDI. The ASQ (Korean) showed low validity for screening neurodevelopmentally delayed premature infants.

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Neonatal Iliopsoas Abscess: The First Korean Case

Iliopsoas abscess (IPA) is rare in neonates. We present a case of neonatal IPA that was initially believed to bean inguinal hernia. A 20-day-old male infant was referred to our hospital for herniorrhaphy after a 2-day history of swelling and bluish discoloration of the left inguinal area and leg without limitation of motion. Abdominal and pelvic ultrasonography suggested a femoral hernia, but the anatomy was unclear. Abdominal computed tomography revealed a multi-septated cystic mass extending into the psoas muscle from the lower pole of the left kidney to the femur neck. Broad spectrum antibiotics were initiated, and prompt surgical exploration was planned. After opening the retroperitoneal cavity via an inguinal incision, an IPA was diagnosed and surgically drained. Culture of the abscess fluid detected Staphylococcus aureus, sensitive to methicillin. The patient was discharged without complication on the 17th postoperative day.

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Surfactant Therapy for Neonatal Respiratory Distress Syndrome: A Review of Korean Experiences over 17 Years

We undertook a multi-hospital collective study to evaluate outcomes of neonatal respiratory distress syndrome (RDS) patients treated with pulmonary surfactant (PS) over 17 yr in Korea (Group I; 1990/91, Group II; 1996, Group III; 2002, and Group IV; 2007). There were 60 neonates in Group I (16 hospitals), 1,179 in Group II (64), 1,595 in Group III (62), and 1,921 in Group IV (57). We adopted Bomsel''s classification to evaluate initial chest radiographic findings, categorized RDS severities, and classified response types to PS therapy. Almost all cases were treated using a single dose in Groups I and II, but 19.5% received multiple-dose therapy in Group IV. In Group IV, Bomsel''s stages III and IV composed 62.9% and initial severities of mild, moderate, and severe RDS were 23.0%, 42.0%, and 35.0%. More infants showed good response in Groups II, III, and IV than in Group I (71.7%, 66.8%, and 69.2% vs. 58.3%). Complications and mortality rate were lower in Group IV than in Groups I, II, and III (mortality rate: 14.3% vs. 40.0%, 30.0%, and 18.7%). We conclude that PS therapy in neonates with RDS had a remarkable impact on improving clinical course and outcomes over 17 yr in Korea.     

The changes in the mortality rates of low birth weight infant and very low birth weight infant in Korea over the past 40 years

Total 36 reports on the mortality rates (MRs) of low birth weight infants (LBWI) and very LBWI (VLBWI) in Korea from the 1967 through 2001 were analyzed. We compared the changes in the MR by 5 and 10-yr interval. The MRs observed by 5-yr intervals from the early 1960s through the 1990s have drastically decreased. The MRs of LBWI are as follows: 23.1% and 23.6% in the 1960s, 17.3% and 16.8% in the 1970s, 14.1% and 14.4% in the 1980s, and 8.1% in the early 1990s. The MRs of VLBWI have also fallen and were reported as follows: 68.2% and 63.7% in the 1960s, 55.8% and 57.6% in the 1970s, 56.2% and 48.1% in the 1980s, 33.5% and 24.5% in the 1990s, and 11.7% in the early 2000s. In every 10-yr period, the MRs of LBWI have decreased from 23.4% in 1960, to 17.0% in 1970, to 14.2% in 1980, and to 8.1% in 1990. The MRs of VLBWI also have decreased from 66.2% in 1960, to 56.7% in 1970, to 50.8% in 1980, to 32.9% in 1990, and to 11.7% in 2000. The MR of LBWI and VLBWI has gone down remarkably due to improvements in neonatology in Korea as shown above.     

Prevalence and Risk Factors for Iron Deficiency Anemia in the Korean Population: Results of the Fifth Korea National Health and Nutrition Examination Survey

This study assessed the prevalence of, and risk factors for, iron deficiency (ID) and iron deficiency anemia (IDA) among participants of the fifth Korean Health and Nutrition Examination Survey, 2010. Of 8,958 participants, 6,758 individuals ≥10 yr had sufficient data for the analysis of anemia and iron status. ID was defined as a transferrin saturation <10% or serum ferritin <15 µg/L. The prevalence of ID and IDA was 2.0% (95% confidence interval [CI], 1.3%-2.6%) and 0.7% (95% CI, 0.3%-1.0%), respectively, in males, and 22.4% (95% CI, 20.7%-24.2%) and 8.0% (95% CI, 6.8%-9.2%), respectively, in females. In reproductive age females, the prevalence of ID and IDA was 31.4% (95% CI, 28.9%-33.8%) and 11.5% (95% CI, 9.6%-13.4%), respectively. Compared to the prevalence of IDA in adult males 18-49 yr, the relative risks of IDA in adults ≥65 yr, lactating females, premenopausal females, and pregnant females were 8.1, 35.7, 42.8, and 95.5, respectively. Low income, underweight, iron- or vitamin C-poor diets were also associated with IDA. For populations with defined risk factors in terms of age, gender, physiological state and socioeconomic and nutritional status, national health policy to reduce IDA is needed.

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Dairy Product Intake Is Inversely Associated with Metabolic Syndrome in Korean Adults: Anseong and Ansan Cohort of the Korean Genome and Epidemiology Study

The objective of this study was to examine the relationship between dairy product intake and the incidence of metabolic syndrome (MetS) and its components among middle-aged Koreans. We examined 7,240 adults aged 40-69 yr without MetS at baseline over a 45.5-month follow-up period. They were taken from the Anseong and Ansan cohort of the Korean Genome and Epidemiology Study. Dairy product intake including milk, yogurt, and cheese was assessed with food frequency questionnaire. At the follow-up, the incidence of MetS was 17.1%. The incidences of MetS components were as follows: low HDL cholesterol (16.2%), abdominal obesity (14.0%), hypertriglyceridemia (13.8%), hyperglycemia (13.3%), and hypertension (13.1%). Adjusting for potential confounders, dairy product consumption frequency was inversely associated with the risk of MetS and abdominal obesity. Hazard ratio (HR) (95% confidence interval) for dairy product consumption more than 7 times/week compared to never was 0.75 (0.64-0.88, P for trend < 0.001) for MetS and 0.73 (0.61-0.88, P for trend < 0.001) for abdominal obesity. HR for milk intake was 0.79 for MetS and 0.82 for abdominal obesity. The results of this study suggest that daily intake of dairy products protects against the development of MetS, particularly abdominal obesity, in middle-aged Koreans.     

Milk intake and its association with metabolic syndrome in Korean: analysis of the third Korea National Health and Nutrition Examination Survey (KNHANES III)

Although previous studies have shown that milk intake has some protective effects on metabolic syndrome (MS), there are few data on the relation between MS and milk consumption in Korean. To evaluate the association between milk intake frequency and MS, 4,890 subjects (2,052 men and 2,838 women) were included in the analysis, based on the national data from representative random sample of the third Korea National Health and Nutrition Examination Survey (KNHANES III) in 2005. We conducted both univariate and multivariate logistic regression analysis with adjustment for confounding factors associated with MS. Mean (±SD) age of subjects was 47.1±15.5 yr. In univariate analysis, the risk of MS was inversely associated with the frequency of milk intake, but this relation was attenuated in multivariate regression. In the individuals with BMI ≥23 kg/m(2), those with highest quartile of milk consumption (once daily or more) had significantly lower risk of MS (OR [95% CI] 0.72 [0.57-0.92] compared with lowest quartile [those rarely consumed]) after adjustment, but not among leaner individuals (BMI <23 kg/m(2)). Korean overweight adults who drink milk more frequently may be protected against MS. But it seems that this relation is somewhat different among MS components.     

Progress and Prospect: A Bibliometric Analysis of Research Papers by Korean Allergists Over Recent Five Years (2009-2013)

Since the establishment of the academic society in 1972, Korean allergists have made continuous efforts to elucidate pathogenic mechanisms and therapeutic advances for allergic diseases. The present study aimed to summarize recent progress and explore future prospects of research performance by Korean allergists. We performed a comprehensive bibliometric analysis for research papers published in the Science Citation Index (SCI) or SCI-expanded journals by Korean allergists between 2009 and 2013. Research performance was quantitatively analyzed for the numbers of papers by publication year, research type, and main topic. In addition, the performance was also examined for qualitative indices, such as impact factor and citation number. A total of 1,091 papers were identified. The number of publication increased continuously, with an annual increase rate of 12.3%. Clinical and basic studies were the most frequent types of research, and recently the number of epidemiological studies has increased. By research topic, asthma was the most commonly studied, accounting for 20.9% of the total number of publications. Notably, the amount of rhinitis/rhinosinusitis research has risen steeply in 2013. Qualitative analyses also indicated continuous progress; the median impact factor of published journals increased from 1.918 in 2009 to 2.746 in 2013, yielding an annual increase rate of 7.4%. In conclusion, the present analyses identified a continuous increase in the research performance of Korean allergists over a recent 5 year period (2009-2013), both quantitatively and qualitatively. A more significant contribution is expected in the forthcoming era.     

The spectrum of NF1 mutations in Korean patients with neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders in humans. NF1 is caused by mutations in the NF1 gene which consists of 57 exons and encodes a GTPase activating protein (GAP), neurofibromin. To date, more than 640 different NF1 mutations have been identified and registered in the Human Gene Mutation Database (HGMD). In order to assess the NF1 mutational spectrum in Korean NF1 patients, we screened 23 unrelated Korean NF1 patients for mutations in the coding region and splice sites of the NF1 gene. We have identified 21 distinct NF1 mutations in 22 patients. The mutations included 10 single base substitutions (3 missense and 7 nonsense), 10 splice site mutations, and 1 single base deletion. Eight mutations have been previously identified and thirteen mutations were novel. The mutations are evenly distributed across exon 3 through intron 47 of the NF1 gene and no mutational hot spots were found. This analysis revealed a wide spectrum of NF1 mutations in Korean patients. A genotype- phenotype correlation analysis suggests that there is no clear relationship between specific NF1 mutations and clinical features of the disease.     

Diagnosis and treatment of nontuberculous mycobacterial pulmonary diseases: a Korean perspective

The incidence of pulmonary disease caused by nontuberculous mycobacteria (NTM) appears to be increasing worldwide. In Korea, M. avium complex and M. abscessus account for most of the pathogens encountered, whilst M. kansasii is a relatively uncommon cause of NTM pulmonary diseases. NTM pulmonary disease is highly complex in terms of its clinical presentation and management. Because its clinical features are indistinguishable from those of pulmonary tuberculosis and NTMs are ubiquitous in the environment, the isolation and identification of causative organisms are mandatory for diagnosis, and some specific diagnostic criteria have been proposed. The treatment of NTM pulmonary disease depends on the infecting species, but decisions concerning the institution of treatment are never easy. Treatment requires the use of multiple drugs for 18 to 24 months. Thus, treatment is expensive, often has significant side effects, and is frequently not curative. Therefore, clinicians should be confident that there is sufficient pathology to warrant prolonged, multidrug treatment regimens. In all of the situations, outcomes can be best optimized only when clinicians, radiologists, and laboratories work cooperatively.