The design of polymer microcarrier surfaces for enhanced cell growth

A variety of neutral and cationic polymers based on polyamino acids were prepared and investigated as microcarriers for cell attachment and growth. Among neutral polymer particles including the alkylated poly(gamma-methyl L-glutamate) (PG) particles, in which the hydrophobicity changes as a function of the length of the alkyl groups, and hydroxy terminal PG particles, the PG particle with the longest alkyl chain (PG-C12) demonstrated the highest cell attachment rate and highest rate of cell growth. Moreover, the introduction of hydroxyl groups (PG-OH) led to a deterioration of cell growth. Cell growth on cationic particles having primary amino groups was drastically dependent upon the anion exchange capacity (AEC). A higher AEC for aminated PG microcarriers inhibited cell growth. In contrast, a higher AEC for cross-linked poly( epsilon -lysine) (PL) microcarriers facilitated cell growth. Cell growth on cationic particles clearly showed a good correlation with the pK(a,app) of the microcarriers, but not with their AEC. The particles with low and high pK(a) values possessed toxically acidic and basic pH microenvironments near the surface, respectively. These microenvironments had cytotoxic effects. On the other hand, no correlation between attachment rate constants and high cell growth was observed. The aminated particles, in which pK(a) were controlled at neutral pH, and PG-C12 produced obviously higher cell growth than did a commercially available microcarrier.     

Influence of hepatitis B virus genotypes on the development of preS deletions and advanced liver disease

Hepatitis B virus (HBV) mutants with deletions in the preS region have not been evaluated for association with viral genotypes. In a case-control study, HBV DNA samples collected from 80 each of carriers infected with HBV genotype B or C were examined for preS deletions. PreS deletion mutants were found in a total of 37 of 160 (23%) HBV carriers. Carriers with preS deletion mutants were older (56.0 +/- 12.7 vs 49.3 +/- 16.9 years, P < 0.05), were infected more frequently with HBV genotype C (84% vs 40%, P < 0.05), and had more advanced disease, such as liver cirrhosis and hepatocellular carcinoma (54% vs 31%; P < 0.05), than did those without such mutants. In a multivariate analysis, genotype C (odds ratio [OR] = 9.3, P < 0.001) and advanced liver disease (OR = 3.1, P < 0.01) were the most significant variables in association with preS deletions. A direct repeat sequence (TCAGG) was found at the start or at the end of preS1 deletions in 6 of the 20 (30%) cases examined, and preS2 deletions in these cases were clustered over the 5'-terminal half of this region. These results indicate that the development of preS deletion mutants depends on HBV genotypes and that it may be associated with progressive liver disease.     

Adrenomedullin concentrations in early 2nd-trimester amniotic fluid: relation to preterm delivery and fetal growth at birth

OBJECTIVE: The purpose of this study was to evaluate whether adrenomedullin concentrations in the early 2nd-trimester amniotic fluid predict preterm delivery or fetal growth at birth. METHODS: The adrenomedullin concentrations in early 2nd-trimester amniotic fluid were measured in 70 pregnancies with term delivery and in 3 pregnancies with preterm delivery. Total and free adrenomedullin concentrations were measured from early 2nd-trimester amniotic fluid samples using an immunoradiometric assay. RESULTS: The amniotic fluid total adrenomedullin concentrations in women with preterm delivery were significantly higher (129.7 +/- 19.6 fmol/ml) than those in women with term delivery (92.5 +/- 28.2 fmol/ml; p < 0.05). There were no significant differences for amniotic fluid free adrenomedullin concentrations and free/total adrenomedullin ratios between the two groups. Total or free adrenomedullin concentrations in the early 2nd-trimester amniotic fluid showed an inverse correlation both with birth weight (r = 0.27, p < 0.05, and r = 0.21, p < 0.05) and height (r = 0.30, p < 0.05, and r = 0.28, p < 0.05). There were no correlations between placental weight and total or free adrenomedullin concentrations in the early 2nd-trimester amniotic fluid. CONCLUSIONS: These results suggest that adrenomedullin concentrations in the early 2nd-trimester amniotic fluid might be related to further in utero fetal growth and that high levels of adrenomedullin in the early 2nd-trimester amniotic fluid may be involved in the occurrence of preterm delivery.     

Longitudinal assessment of the middle cerebral artery peak systolic velocity in healthy fetuses and in fetuses at risk for anemia

OBJECTIVE: Our purpose was to assess the feasibility of longitudinal assessment of the middle cerebral artery peak systolic velocity (MCA-PSV) to predict fetuses who will have severe anemia. STUDY DESIGN: Doppler measurement of MCA-PSV was serially performed in 15 healthy fetuses (99 measurements; range: 4-9 per fetus), 8 fetuses who were mildly anemic (41 measurements; range: 3-10 per fetus), and 11 who were severely anemic (50 measurements; range: 2-7 per fetus) at their first cordocenteses. Linear models were fitted to the data from individual fetuses and the slopes were determined. The average rate of change (slope) of MCA-PSV as a function of gestational age in the 3 groups was calculated from these data. Estimated average slopes were computed using restricted maximum likelihood. F tests were used for hypothesis tests, with the degrees of freedom based on the Kenward and Roger approximation. The values of MCA-PSV and hemoglobin were expressed as multiples of the median (MoM). A P <.05 indicated statistical significance. RESULTS: Gestational age at the time of the Doppler studies ranged from 15.1 to 41 weeks in the healthy fetuses. It was between 15 and 33.4 weeks in the fetuses who became anemic. The estimated average slopes increased with the degree of anemia (P =.03). The difference in mean slope between the severely anemic sample and the healthy sample was statistically significant (estimated difference = 2.2, SE =.65, P =.01). The difference in mean slope between the mildly anemic and healthy samples was not statistically significant (estimated difference = 1.1, SE =.06; P =.08). CONCLUSIONS: We have demonstrated that the MCA-PSV slope is an excellent tool for identifying those fetuses who will become severely anemic and, therefore, need to be followed up more closely during the pregnancy. Our findings expand the clinical applications to which Doppler ultrasonography can be applied in monitoring pregnancies at risk for fetal anemia.     

Peculiar form of cerebral microdysgenesis characterized by white matter neurons with perineuronal and perivascular glial satellitosis: A study using a variety of human autopsied brains

Microdysgenesis (MD) is a neuropathological term that implies a variety of minor developmental abnormalities of the brain. Recently, MD has been used for pathological diagnosis of cerebral tissues surgically resected from epileptic patients. However, criteria or consensus on pathological diagnosis of MD is still vague and controversial because of the lack of control studies. Therefore, this study paid special attention to the presence of white matter neurons with perineuronal glial satellitosis (WMN-GS) and perivascular glial satellitosis (PVGS) in the white matter, which are occasionally observed in epileptic foci, in order to clarify whether they could be handled as definite findings of MD. The materials included 80 autopsied whole brains ranging from normal subjects to patients with cerebrovascular disorder, neurodegenerative diseases and malformations. In each case, the presence of WMN-GS and/or PVGS was searched in 10 gyri in all five lobes (rostral frontal lobe, caudal frontal lobe, parietal lobe, temporal lobe and oc-cipital lobe) and evaluated. Statistically significant, WMN-GS and/or PVGS preferentially appeared in a diseased group consisting of neuronal migration disorder and related conditions, such as polymicrogyria, nodular heterotopia or tuberous sclerosis, leading to a suggestive conclusion that the presence of WMN-GS and/or PVGS could be a peculiar form of MD possibly derived from neuronal migrational arrest or related events, even if they appear alone without any other gross abnormalities.     

Osteoconductive and hemostatic properties of apatite formed on/in agarose gel as a bone-grafting material

The biologic behavior of hydroxyapatite formed on/in agarose (HA/agarose) gels with the use of a novel alternate soaking process was compared with commercially available Bone Ject (True-Bone ceramic-collagen combined bone-graft material, Koken, Japan) as a filler for the tooth-extraction sockets of six adult monkeys (Macasa fascicularis). After the monkeys' first premolars were extracted, the defects created were replaced with one of the following materials: (a). HA/agarose created by 12 soaking cycles, (b). HA/agarose created by 9 soaking cycles, (c). Bone Ject, and (d). no material implantation (control). The time of hemostasis in each extraction site was estimated, and the samples were then studied histologically. In the controls, the time of hemostasis was about 5 min. The Bone Ject particles were easily washed out by bleeding, and the time of hemostasis was about 15 min. The HA/agarose gel was densely packed into the bony defect. The hemorrhage from the defects stopped within a few seconds after graft placement. This hemostasis was most likely related to the compactibility and adhesiveness of the material. After 12 weeks of implantation, free Bone Ject particles surrounded by inflammatory cells were observed. The bony defect filled with the HA/agarose gels was completely absorbed and replaced by newly formed bone possessing bone marrow. There was no difference in the biologic behavior of HA/agarose gels created by 9 versus 12 soaking cycles. The present study suggests that HA/agarose gels may play an important role as an alternative biodegradable bone-graft material for autogenous bone in humans.     

A living case of pulmonary ossification associated with osteoclast formation from alveolar macrophage in the presence of T-cell cytokines

A 61-year-old woman had been coughing up blood-tinged sputum since May 1998. Chest radiography and computed tomography (CT) scans revealed a solitary mass (3 cm in greatest dimension) in the right lower field, accompanied by a surrounding area of ground glass and reticular appearance. Surgical lung biopsy was performed to the surrounding area. The pathological diagnosis was pulmonary ossification of the dendriform type. Alveolar macrophages obtained from her lung differentiated into tartrate-resistant acid phosphatase (TRAP)-positive multinucleated giant cells (MGCs) in the presence of autologous T cells or of macrophage colony stimulating factor (M-CSF) and interleukin-4 (IL-4). This results suggest the possibility that monocytes/macrophages may have the ability to form osteoclasts in the presence of cytokines that may be involved in the development of pulmonary ossification.