Variation in human β‐defensin genes: new insights from a multi‐population study

Human β‐defensin 2 (hBD‐2) and hBD‐3, encoded by DEFB4 and DEFB103A, respectively, have shown anti‐HIV activity, and both genes exhibit copy number variation (CNV). Although the role of hBD‐1, encoded by DEFB1, in HIV‐1 infection is less clear, single nucleotide polymorphisms (SNPs) in DEFB1 may influence viral loads and disease progression. We examined the distribution of DEFB1 SNPs and DEFB4/103A CNV, and the relationship between DEFB1 SNPs and DEFB4/103A CNV using samples from two HIV/AIDS cohorts from the United States (n = 150) and five diverse populations from the Coriell Cell Repositories (n = 46). We determined the frequencies of 10 SNPs in DEFB1 using a post‐PCR, oligonucleotide ligation detection reaction–fluorescent microsphere assay, and CNV in DEFB4/103A by real‐time quantitative PCR. There were noticeable differences in the frequencies of DEFB1 SNP alleles and haplotypes among various racial/ethnic groups. The DEFB4/103A copy numbers varied from 2 to 8 (median, 4), and there was a significant difference between the copy numbers of self‐identified whites and blacks in the US cohorts (Mann–Whitney U‐test P = 0.04). A significant difference was observed in the distribution of DEFB4/103A CNV among DEFB1 ‐52G/A and ‐390T/A genotypes (Kruskal–Wallis P = 0.017 and 0.026, respectively), while not in the distribution of DEFB4/103A CNV among ‐52G/A_‐44C/G_‐20G/A diplotypes. These observations provide additional insights for further investigating the complex interplay between β‐defensin genetic polymorphisms and susceptibility to, or the progression or severity of, HIV infection/disease.     

Subcellular organization of camkii in rat hippocampal pyramidal neurons

Calcium/calmodulin‐dependent protein kinase II (CaMKII) plays a key role in N‐methyl‐D‐aspartate (NMDA) receptor‐dependent long‐term synaptic plasticity; its location is critical for signal transduction, and may provide clues that further elucidate its function. We therefore examined the subcellular localization of CaMKII in CA1 stratum radiatum of adult rat hippocampus, by using immuno‐electron microscopy after chemical fixation. When tissue was fixed quickly, the concentration of CaMKIIα (assessed by pre‐embedding immunogold) was significantly higher in dendritic shafts than in spine heads. However, when tissue was fixed 5 minutes after perfusion with normal saline, the density of labeling decreased in dendritic shaft while increasing in spine heads, implying rapid translocation into the spine during brief perimortem stress. Likewise, in quickly fixed tissue, CaMKII within spine heads was found at comparable concentrations in the “proximal” half (adjacent to the spine neck) and the “distal” half (containing the postsynaptic density [PSD]), whereas after delayed fixation, label density increased in the distal side of the spine head, suggesting that CaMKII within the spine head moves toward the PSD during this interval. To estimate its distribution at the synapse in vivo, we performed postembedding immunogold staining for CaMKII in quick‐fixed tissue, and found that the enzyme did not concentrate primarily within the central matrix of the PSD. Instead, labeling density peaked ～40 nm inside the postsynaptic membrane, at the cytoplasmic fringe of the PSD. Labeling within 25 nm of the postsynaptic membrane concentrated at the lateral edge of the synapse. This lateral “PSD core” pool of CaMKII may play a special role in synaptic plasticity. J. Comp. Neurol. 521:3570‐3583, 2013. © 2013 Wiley Periodicals, Inc.     

Cisplatin-DNA damage in p21WAF1/Cip1 deficient mouse keratinocytes exposed to cisplatin

In response to DNA damage, cell cycle arrest, apoptosis, and DNA repair are mediated by a TP53 pathway that induces p21(WAF1/Cip1). The chemotherapeutic drug cis-diamminedichloroplatinum-II (cisplatin) damages cellular DNA by forming cis-diammineplatinum-N(7)-d[GpG] and cis-diammine-platinum-N(7)-d[ApG] adducts. To investigate the role of p21, skin keratinocytes from p21(WAF1/Cip1) wild-type (+/+), heterozygous (+/-), and null (-/-) mice, cultured in calcium levels designed to maintain a proliferating state, were exposed to 5 microM cisplatin continuously for 0, 8, 24, 48 and 72 h. At all time points the (+/-) cells had the fewest Pt-DNA adducts, and at 24 h mean Pt-DNA adduct levels were 541, 153 and 779 fmol adduct/mug DNA for p21(WAF1/Cip1) (+/+), (+/-) and (-/-) cells, respectively [P < 0.05 for (+/+) versus (+/-) and (-/-) versus (+/-)]. In order to understand underlying events, we examined p21(WAF1/Cip1) messenger RNA (mRNA), cell cycle arrest, and apoptosis in these cells. At 48 h of cisplatin exposure p21(WAF1/Cip1) mRNA expression was 2-fold higher in the (+/+) cells, compared to the (+/-) cells. At 24 h, the % of cells in S-phase in cisplatin-exposed cultures, compared to unexposed cultures, was decreased by 51, 40 and 11% in p21(WAF1/Cip1) (+/+), (+/-) and (-/-) cells, respectively (P = 0.04, ANOVA). At 24, 48 and 72 h the % of cisplatin-exposed (+/+) cells in apoptosis was 9.4-10.5%, while the cisplatin-exposed (+/-) and (-/-) cells had 1.2-3.7% of cells in apoptosis. The data support the interpretation that DNA replication arrest and apoptosis do not completely explain the low levels of Pt-DNA adducts in the (+/-) cells, and suggest that p21(WAF1/Cip1) controls activity resulting in either low Pt-DNA adduct formation or enhanced Pt-DNA adduct removal.     

Bleeding following pregnancy loss before 6 weeks' gestation

BACKGROUND: Pregnancy loss before 6 weeks' gestation is common, but little has been reported about the associated bleeding. We compared women's bleeding following a pregnancy loss before 6 weeks' gestation with their typical menstruation. METHODS: Women provided daily urine samples while trying to become pregnant and recorded the number of pads and tampons used each day. Thirty-six women had complete bleed data for a loss before 6 weeks' gestation and one or more non-pregnant cycles. RESULTS: Mean bleed length following a pregnancy loss was 0.4 days longer than the woman's average menstrual bleed (P = 0.01), primarily because of more days of light bleeding. Although there was no overall increase in the total number of pads plus tampons used, women with losses bled less than their typical menses following pregnancies of very short duration and more than usual for the pregnancies lasting the longest. CONCLUSIONS: Overall, the bleeding associated with pregnancy loss before 6 weeks' gestation is similar to menstrual bleeding and unlikely to be recognized as pregnancy loss. The intriguing finding that pregnancies of very short duration were associated with less bleeding than the woman's typical menses might reflect endometrial factors associated with loss.     

Utilization of peritoneal dialysis in the United States: Reasons for underutilization,specifically in New York State and the boroughs of New York City

Peritoneal dialysis (PD) is currently underutilized in the United States (US), even within resource-rich neighborhoods. We analyzed data from US Renal Data Service to determine PD utilization within the US, New York State (NYS), selected boroughs within New York City (NYC), and Boston, Massachusetts. We then compared the odds of selecting PD with hemodialysis (HD) and analyzed how diabetes mellitus status, age >65 years, gender, and race influenced PD utilization between 2010 and 2016. We then compared a high-volume PD center (HVC) with a low-volume PD center (LVC). The odds of starting PD vs HD were as follows: Brooklyn 0.30 (0.25-0.36; <0.0001), Bronx 0.56 (0.47-0.67; <0.0001), Queens 0.66 (0.54-0.80; <0.0001), and Manhattan 0.61 (0.52-0.71; <0.0001). In 2016, the odds of starting PD compared with the rest of the US were as follows: Brooklyn 0.14 (0.08-0.22; <0.0001), Bronx 0.39 (0.27-0.56; <0.0001), Queens 0.32 (0.23-0.45; <0.0001), Manhattan 0.54 (0.36-0.79; 0.002), and Boston 0.89 (0.58-1.4; 0.624). Analysis of influencing factors showed that only age >65 significantly (<0.0001) influenced PD modality selection in Brooklyn and Boston. Differences between HVC and LVC in terms of modality transition, peritonitis rate, or provider:patient ratio were not statistically significant. Factors that influence PD utilization in urban neighborhoods are discussed and remediation measures are proposed.