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We sought to clarify the survival and neurodevelopmental outcomes of very low birth weight infants (VLBWIs) and to identify risk factors for death or neurodevelopmental impairment (NDI) in VLBWIs at our hospital. The total study population was 217 infants born in 2005-2012 weighing 1,500 g. We compared their outcomes with those from previous reports analyzed the causes of death. Risk factors for death after discharge or NDI were evaluated by a multivariate logistic regression analysis. The incidences of death or NDI reported revealed in this study and the database of Neonatal Research Network of Japan were 25.3% and 19.6% (p＝0.039), respectively. The main causes of death before discharge were intraventricular hemorrhage, sepsis, and persistent pulmonary hypertension of the newborn. The significant risk factors for death after discharge or NDI were early gestational age (weeks) and periventricular leukomalacia (adjusted odds ratio [95% confidence interval, p-value], 0.72 [0.54-0.94, 0.017] and 6.90 [1.35-38.25, 0.021], respectively). These factors must be addressed in order to improve treatment strategies for VLBWIs.

Mothers of preterm infants may find it difficult to express breast milk. There is a low breast milk rate among preterm infants at discharge at our hospital, and here we tested the hypothesis that milk expression factors were the cause of the low rate. The study subjects were born before 33 gestational weeks at our hospital between March 2005 and June 2014. Nutritional evaluation was performed at discharge and noted whether breast milk, infant formula, or a mix of the 2 was being given. We compared the group given breast milk or the mix versus the group given formula. Of the 337 infants, 40 cases were excluded. Data from 297 infants were analyzed. The mean (SD) gestational age and birth weight were 29.5 (2.4) weeks and 1,230 (391) g, respectively. At discharge, 26 (8.8% ), 102 (33.3% ), and 174 (57.9% ) infants were given breast milk, formula, and the mix, respectively. A multivariate logistic regression analysis showed that the first milk expression (h) was the risk factor for the formula group: adjusted odds ratio (95% confidence interval) 1.06 (1.02-1.09) and p=0.002. Delayed first milk expression could affect the low breast milk rate at discharge. Improvement of milk expression should be achieved to promote breastfeeding.

Ventriculoperitoneal shunts (VPSs) are used for the treatment of hydrocephalus. Here we analyzed the outcomes of VPS placements in 24 infants to determine the risk factors for shunt failure. The infants had undergone the initial VPS operation in our hospital between March 2005 and December 2013. They were observed until the end of January 2014. We obtained Kaplan-Meier curves and performed a multivariate Cox regression analysis of shunt failure. Of the 24 cases, the median (range) values for gestational age, birth weight, and birth head circumference (HC) were 37 (27-39) wks, 2,736 (686-3,788) g, and 35.3 (23.0-45.3) cm, respectively. The total number of shunt procedures was 45. Shunt failure rates were 0.51/shunt and 0.0053/shunt/year. Shunt infection rates were 0.13/shunt and 0.0014/shunt/year. The Kaplan-Meier analysis revealed an increased risk for shunt failure in infants <1 month old or in the HC >90%tile. The Cox regression analysis yielded hazard ratios (HRs) of 2.93(95% confidence interval (CI), 0.96-10.95, p=0.059) for age <1 month, and 4.46 (95%CI:1.20-28.91, p=0.023) for the HC >90%tile. The multivariate Cox regression analysis showed adjusted HRs of 17.56 (95%CI:2.69-202.8, p=0.001) for age <1 month, and 2.95 (95%CI:0.52-24.84, p=0.228) for the HC >90%tile. Our findings thus revealed that the risk factors for shunt failure in infants include age <1 month at the initial VPS placement.

Since the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) in 2007, invasive pneumococcal disease has declined, but the incidence of Streptococcus pneumoniae serotype 19A has risen worldwide. The present study examined changes in the features of invasive pneumococcal disease since the introduction of the PCV7 in Kochi, Japan. Pediatric cases of invasive pneumococcal disease were investigated before and after vaccine introduction (January 2008 to December 2013). Cases of invasive pneumococcal disease tended to decrease after PCV7 introduction. In addition, before introduction of the vaccine, most serotypes causing invasive pneumococcal disease were those included in the vaccine. However, after the introduction, we found cases infected by serotypes not covered by vaccine. Penicillin-resistant S. pneumoniae was the predominant serotype causing invasive pneumococcal disease before introduction of the PCV7, and the susceptibility of this serotype to antibiotics improved after vaccine introduction. Serotype isolates identified after vaccine introduction were also relatively susceptible to antibiotic therapy, but decreased susceptibility is expected.

A rare case of variant Philadelphia (Ph1) chromosome positive [46, XX, t (9; 22) (q34; q11), inv (9) (9q22; 22q13)] chronic myelocytic leukemia (CML) was described. The patient, 73 years old female, was hospitalized to our hospital because of leukocytosis. Hematological findings corresponded to those of CMLs. However, this case lacked hepatosplenomegaly. Southern blot analysis using a 3 breakpoint cluster region (bcr) probe revealed a bcr rearrangement. The patient has been in the chronic phase for sixteen months without treatment. Clinical and chromosomal changes are under observation in order to get accumulate data for a pathophysiological analysis of variant Ph1 positive CMLs.

We performed a cytogenetic study on 140 nonpolymalformed patients with mental retardation of clinically undefined origin, using a high resolution banding technique, to determine how much chromosome abnormalities contribute to the etiology of this condition. A total of 15 patients (10.7%) were found to have autosomal or sex chromosomal abnormalities. Autosomal abnormalities included partial monosomy (5 cases), reciprocal translocation (one case), 13/14 robertsonian translocation (3 cases), unbalanced translocation (one case), inverted duplication of 15q (one case) and mosaic trisomy 21 (one case). Sex chromosomal abnormalities comprised structural rearrangement of the short arm of the X chromosome (one case) and 47, XXY in a pure or mosaic form (two cases). It should be noted that four out of the 5 cases of partial monosomy had subtle interstitial deletions, which might have been unidentified by the conventional G-banding method alone. In one case of the robertsonian translocation 46,XY,t(13;14)/45,XY,t(13;14), a small deletion was thought to have occurred in the cells with a chromosome number of 45. Comparison of clinical features of the 15 chromosomally abnormal patients with those of patients with normal karyotypes did not show any clinical parameter indicative of chromosome imbalance. These results suggest that a subtle chromosomal deletion is specific to mental retardation associated with few malformations. We believe that diagnostic evaluation of mentally retarded patients, even if nonmalformed, should include chromosome analysis using a high resolution banding technique.