Controlled Release of Lysozyme Using Polyvinyl Alcohol-Based Polymeric Nanofibers Generated by Electrospinning.

Polymeric nanofibers generated via electrospinning offer a promising platform for drug delivery systems. This study examines the application of electrospun polyvinyl alcohol (PVA) nanofibers for controlled lysozyme (LZM) delivery. By using various PVA grades, such as the degree of polymerization/hydrolysis, this study investigates their influence on nanofiber morphology and drug-release characteristics. LZM-loaded PVA monolithic nanofibers having 50% drug content exhibit efficient entrapment, wherein rapid dissolution is achieved within 30 min. The initial burst of LZM from the nanofiber was reduced as the LZM content was lowered. The initial dissolution is greatly influenced by the choice of PVA grade used; fully hydrolyzed PVA nanofibers demonstrate controlled release due to the reduced water solubility of PVA. Furthermore, coaxial electrospinning, which creates core-shell nanofibers with polycaprolactone as a controlled release layer, enables sustained LZM release over an extended period. This study confirms a correlation between PVA characteristics and controlled drug release and provides valuable insights into tailoring nanofiber properties for pharmaceutical applications.

Fiber dissection technique for demonstrating the lateral lemniscus of the human brain.

This report describes fiber dissection technique for tracing the auditory pathway from the cochlear nerve to the medial geniculate body via the lateral lemniscus, inferior colliculus and inferior brachium. Some fibers of the lateral leminiscus appear to reach the thalamus in conjunction with fibers of the medial lemniscus.

Proliferating cells in the rat anterior pituitary during the postnatal period: immunoelectron microscopic observations using monoclonal anti-bromodeoxyuridine antibody.

Proliferating cells in the male rat anterior pituitary at 1, 3, 5, and 8 weeks of age were labeled with bromodeoxyuridine (BrdU) and studied by light and electron microscopic immunocytochemistry using anti-BrdU. They decreased in number from 402+/-31/mm(2) at 1 week to 50+/-1.5/mm(2) at 8 weeks, while their cell area increased by about twofold during this period. They had a slightly higher nucleus/whole cell (N/C) ratio than non-proliferating cells. According to their ultrastructure we classified them into granular and agranular cells. The percentage of granular cells ranged from 73% to 82% of all the proliferating cells during the period studied. They had many granules of various sizes and shapes, and some contained growth hormone and prolactin. Agranular cells, constituting 18-27% of proliferating cells, were small and had a high N/C ratio, indicating their immaturity. Moreover, they showed several features of folliculo-stellate (FS) cells: they showed no secretory granules in the cytoplasm, extended thin cytoplasmic processes, and sometimes they constructed a follicle among them. These results suggest: (1) the majority of proliferating cells were mature cells producing anterior pituitary hormone(s) and (2) most of the agranular proliferating cells maybe FS cells. The possibility of the latter is discussed.

The distribution and morphology of lymphatic vessels on the peritoneal surface of the adult human diaphragm, as revealed by an ink-absorption method.

Application of india ink to the peritoneal and pleural surfaces of the adult human diaphragm allowed visualization of the distribution and morphology of the lymphatic vessels by light microscopy and scanning electron microscopy. The diaphragms examined had been fixed and stored in 10% formalin. Numerous lymphatic vessels were stained black with india ink, presenting reticular, radial-meshwork, ladder-like and lacy patterns. They were distributed throughout the entire sternocostal part. Analysis by light and scanning electron microscopy of the areas indicated by india ink revealed the presence of primary lymphatic vessels that formed lymphatic lacunae and stomatal openings to the peritoneal cavity. A layer of secondary collecting lymphatic vessels was located cranially with respect to the layer of primary lymphatic vessels. Thus, the peritoneum had at least two layers of lymphatic vessels. These lymphatic vessels were not tubular vessels but resembled flat cisternae, as has been suggested in the case of the mouse diaphragm. The pleura lacked lymphatic stomata and had no such double-layered lymphatic organization. This is the first report that showed distribution and morphology of the lymphatic vessels in the diaphragmatic peritoneum of the formalin-fixed, adult human diaphragm. The method and results in the present study may contribute to morphological analysis of the lymphatic system in the wall of the human body cavity.

Proliferation and differentiation of rat anterior pituitary cells.

Studies on the proliferation and differentiation of the cells in the rat anterior pituitary were reviewed. The mitotic rate of anterior pituitary is low in the control adult animal, but it increased by stimulation, such as by ablation of the target organ. A high mitotic rate was also reported during ontogenesis of the pituitary. Concomitant with this augmented mitosis, the number of those cells that are double-labeled with the marker of proliferation and the antibody to pituitary hormones increased as well. The percentage of these double-labeled cells in all the proliferating cells is less than 10%, suggesting that about 1/10 of the proliferating cells are involved in producing pituitary cells. This percentage for GH cells is 30-40% at most, suggesting very active production of them. The percentage of the double-labeled cell in all the hormone-producing cells is within 10% in all cell-types of the pituitary, including GH cells. When the proliferation is detected by a more sensitive method, this percentage increased to 20-40%, suggesting that the self-mitosis of the pituitary cells contributes considerably to their proliferation at a certain period during their ontogenesis.

Mitoses of thyrotrophs contribute to the proliferation of the rat pituitary gland during the early postnatal period.

Development of thyrotrophs in the rat pituitary at 3, 7 and 10 days after birth was quantitatively studied by labelling the proliferating cells with bromodeoxyuridine (BrdU) and with the proliferating cell nuclear antigen (PCNA), and the immunostaining of thyrotrophs was applied to the same tissue section. Double administration of BrdU at 9:00 h and 19:00 h, increased the numerical volume density (Nv) of labelled cells by about 1.5-fold of that obtained with a single injection at 9:00 h. When PCNA was used to determine hyperplasia, the Nv of labelled cells further increased greatly. In accordance with these results, the Nv of the thyrotrophs that were also labelled with BrdU or PCNA increased likewise. These cells comprised 3-7% of all BrdU- or PCNA-labelled cells, indicating that about 1/20 of the proliferating cells are involved in producing new thyrotrophs. On the other hand, their percentage in all thyrotrophs was 8.8%, 18.4% or 38.7% in 3-day neonates with single or double BrdU injections, or when PCNA was detected. These high percentages indicate a considerable contribution by the mitosis of already existing thyrotrophs to their proliferation in the early postnatal period.

Relative positions of the arteries and veins on the dorsolateral surface of the human cerebrum.

We investigated whether arteries pass superficial to veins or whether veins pass superficial to arteries at artery-vein crossings on the anterior, dorsolateral, and posterior surfaces of the human cerebrum. We examined a total of 2,266 artery-vein crossings on 40 sides of 20 cadavers. At 2,059 crossings (91%), the vein passed superficial to the artery. Thus, vein (V), artery (A), and nerve (N), if we regard the cerebrum as nerve, were generally arranged in the order VAN from the superficial to the deep layers. This concept is important for a positional understanding of blood vessels on the cerebrum and it is useful for the understanding of fluid-drainage pathways from the cerebral cortex in various pathological conditions.