Effective wound bed preparation using maggot debridement therapy for patients with critical limb ischaemia.

OBJECTIVE: Patients with critical limb ischaemia (CLI) lack sufficient blood flow in to the limb, which leads to difficulties in the normal wound healing process. Therefore, maggot debridement therapy (MDT) has not generally been recommended for CLI patients. We evaluated the effectiveness of wound bed preparation by MDT in CLI patients who had undergone mid-foot amputation. METHODS: Patients who underwent mid-foot amputation after angioplasty between April 2014 and October 2016 were retrospectively investigated by classifying them into an MDT group or a conventional treatment group. The primary outcome was defined as achievement of wound healing. Secondary outcomes were the proportions of amputation-free survival (AFS) and successful ambulatory improvement. Propensity scores were used to evaluate treatment outcomes based on five factors: ankle-brachial index, skin perfusion pressure of the foot, nutritional status, experience with dialysis and age. RESULTS: A total of 39 patients (39 legs) were included, seven within the MDT group and 32 in the conventional treatment group. Clinical backgrounds of the two groups showed no significant differences except for higher albumin levels for the MDT group (3.5±0.4g/dl; p=0.014). The wound healing proportion was significantly higher in the MDT group (86%) than in the control group (38%) (p=0.035). At 6 months after amputation, no significant differences were found between the two groups for AFS (71% versus 47%; p=0.41) or ambulatory capability (43% versus 28%; p=0.65). This result was also similar to the propensity score adjustment analysis. CONCLUSIONS: The efficacy of MDT with favourable wound bed preparation was shown in our CLI patients based on effective debridement and granulation formation by maggots, avoiding the loss of their heels. Wound-healing rates after MDT were higher for patients than for those receiving conventional treatment. MDT is considered a valid adjuvant treatment strategy for patients with CLI after revascularisation treatment is conducted. More favourable wound bed preparation and successful graft take were achieved in the MDT group, suggesting the effectiveness of MDT for wound healing in CLI patients.

XAFS study on the sulfidation mechanisms of Co-Mo catalysts supported on activated carbon and alumina: effect of complexing agent.

The effect of nitrilotriacetic acid (NTA) as a complexing agent on the sulfidation mechanisms of Co-Mo catalysts supported on activated carbon and alumina was examined by the XAFS technique. The XAFS results revealed that NTA interacted with Co atoms and formed the Co-NTA interaction, while it showed almost no influence on the local structures around Mo atoms. The Co-NTA interaction suppressed the aggregation of cobalt atoms and the interaction between cobalt and alumina during sulfiding, and consequently promoted the formation of the Co-Mo-S phase.

Two unusual cases of argyria: the application of an improved tissue processing method for X-ray microanalysis of selenium and sulphur in silver-laden granules.

Using a simplified tissue processing method for X-ray microanalysis, we have characterized the elemental composition of silver-laden granules deposited in the skin of two patients with argyria. The introduction of ethanol as a fixative and nylon mesh as a supporting grid, and the avoidance of electron staining, have facilitated the minimization of unwanted microanalytical emission peaks generated from conventional chemicals and metals, which often disturb precise clarification of elements of pathological interest in argyria. The two main X-ray microanalytical findings in this study were: (i) the consistent presence of sulphur and the inconsistent occurrence of selenium in the silver-laden granules, and (ii) successful mapping of the distribution of trace amounts of selenium present in argyria. The simplified tissue processing method could be useful in future critical X-ray microanalysis studies.

Influence of chronic alcohol consumption on the development of altered hepatocellular foci in rats.

The effect of chronic alcohol consumption on the development of altered hepatocellular foci was examined in 150 male Slc:Wistar rats fed an ethanol solution (0, 5 or 20%, w/v) ad libitum instead of drinking water. In the 120th week of the treatment period, the liver was examined histopathologically. There was no significant difference in the incidence, number and volume fractions of altered hepatocellular foci between the 0% and the 5% ethanol groups. In the 20% ethanol group, the incidence of altered hepatocellular foci was significantly higher than in the 0% ethanol group, and the number and the volume fraction of altered hepatocellular foci were significantly greater than in the 0% and the 5% ethanol groups. These results indicate that chronic consumption of a large amount of alcohol promotes the development of altered hepatocellular foci. However, there was no statistically significant difference in the incidence of benign liver cell tumours and hepatocellular carcinoma among the three groups.

A study of endotoxin-associated hepatotoxicity on proliferating hepatocytes.

It is thought that regeneration of the liver provides a state of preparedness for the Shwartzman reaction and contributes to the development of endotoxin-associated massive hepatic necrosis following partial hepatectomy. Therefore we examined endotoxin hepatotoxicity in rats with hepatic regeneration after 35% hepatectomy and in rats with liver cell proliferation induced by lead nitrate. Biochemical and histopathological studies showed no enhanced endotoxin hepatotoxicity in either partially hepatectomized rats or in rats with lead nitrate-induced liver cell proliferation. These results indicate that the development of endotoxin-associated hepatic damage after partial hepatectomy may not relate to regeneration and proliferation of the liver.

Mechanism of liver injury following ischemia.

To clarify whether ischemic liver injury is due to ischemia itself or reperfusion, histopathological and functional changes in the liver were examined before and after liver ischemia in rats with porto-systemic collateral channels. Effects of oxygen-derived free radical scavengers or an inhibitor of platelet aggregation on development of ischemic liver injury were also examined. Liver ischemia was produced by ligation of the portal vein and hepatic artery at liver hilum for 1 hr. The primary lesion of ischemic liver injury was cloudy swelling of liver cells in the periportal and midzonal regions; it developed during ischemia. The cloudy swelling of liver cells induced uneven distribution of sinusoidal blood flow after reperfusion, and consequently individual liver cell necrosis and focal hepatocellular necrosis in the midzonal regions developed later. Elevation of cytoplasmic enzyme activities in the serum after reperfusion was due to leakage across the damaged plasma membrane of liver cells. The treatment with superoxide dismutase, catalase, or heparin had not altered the liver injury that was attributed to ischemia, biochemically and histologically. These results suggest that ischemic liver injury is due to liver cell damage developed during ischemia, and that the ischemic liver injury is not alleviated or prevented by superoxide dismutase, catalase, or heparin.

Electron microscopic observations of concentric lamellar bodies within mesenchymal cells of anagen hair dermal papilla.

The presence of 2 forms of the concentric lamellar bodies was observed in the mesenchymal cells within dermal papilla of normal scalp anagen hairs. They are those composed of agranular membrane arrays in association with beta-glycogen particles (glycogen bodies) and those of smooth-surfaced endoplasmic reticulum (smooth-surfaced lamellar bodies). On rare occasions these 2 forms of the concentric lamellar bodies were simultaneously present within the same cells. Transitional forms between the smooth-surfaced lamellar bodies and phagosegresomal granules were also encountered.

Ultrastructure and x-ray microanalysis of siderosome.

Comparative ultrastructural examination and energy-dispersive electron probe X-ray microanalysis were performed on a long standing skin lesion of hemosiderotic histiocytoma. Iron-containing fine particles present in siderosome were the main element of interest. Qualitative study of spectra over the siderosomes clearly demonstrated the characteristic X-ray energy emitted by iron, whereas spectra obtained from adjacent cytoplasm revealed minimal iron peak. On quantitative evaluation of the spectra yielded from various siderosomes, iron counts intensity was found to be proportionally increased with increment in amount and electron opacity of the siderosomal inclusion. Accounts on chemical nature of the siderosomal inclusion and on the presence of lipid residue in cytoplasms were noted.

Fine structure of unmyelinated nerves in neonatal skin.

The fine structure of unmyelinated cutaneous nerve fibers in newborns was examined in lesions of adnexal polyp of neonatal skin. In the neonatal cutaneous nerves, unmyelinated fibers outnumbered myelinated ones. The unmyelinated fibers consisted of Schwann cells, axons and basal lamina. Their ultrastructural organization was basically similar to that in the adult skin. However, some of the unmyelinated fibers contained axonal bundles which suggested a state of cytoarchitectual immaturity or incomplete growth. Phagocytosis of melanosomes by Schwann cells was also observed.

Neonatal sebaceous glands: fine structure of sebaceous and dendritic cells.

Ultrastructural features of sebaceous glands in newborns were examined in adnexal polyp lesions of neonatal skin. Material for electron microscopy was obtained from the nipple areola of 10 Japanese newborn babies of both sexes, less than 8 days of age. The cell organization of the neonatal sebaceous acini consisted of undifferentiated, differentiating, and mature sebaceous cells, and the sequence of sebaceous transformation seemed to be consistent with that described in the postnatal acini. The sheet of continuous basal lamina covering the sebaceous acini was neither distorted nor convoluted. This configuration in the basal lamina revealed no convincing evidence for physiological involution of the neonatal sebaceous cells were identified at the outer periphery of the sebaceous glnads. Melanocytes in symbiosis with the sebaceous acini in concurrent presence of Langerhans cells.

Melanogenic melanocytes in human sebaceous glands.

Electron microscopic observations revealed for the first time a small number of active melanocytes synthesizing distinctive melanin-containing organelles (melanin granules)in the ducts and acini of human sebaceous glands.

Lymphatic transport and phagocytosis of melanosomes in blue nevus.

The present paper describes ultrastructural aspect of lymphatic transport of dermal melanosomes in blue nevus. At least two processes may be responsible for the transport across the lymphatic endothelial wall in vivo; one is the passage of melanophages through the intercellular junctions and the another of free melanosomes. Phagocytosis of melanosomes by lymphatic endothelial cells is discussed.