Antitumor activity of chitosan from mayfly with comparison to commercially available low, medium and high molecular weight chitosans

Insects' cuticles have a potential to be evaluated as a chitin source. Especially adults of aquatic insects like mayflies (order Ephemeroptera) swarm in enormous numbers in artificially lit areas while mating in spring and then die by leaving huge amounts of dead insects' bodies. Here in this study, mayfly corpses were harvested and used for production of low MW chitosan. Dried mayfly bodies had 10.21% chitin content; mayfly chitin was converted into chitosan with efficiency rate of 78.43% (deacetylation degree, 84.3%; MW, 3.69 kDa). Cytotoxicity and anti-proliferative activity of mayfly and commercially available shrimp chitosans (low, medium, and high MW) were determined on L929 fibroblast and three different cancer types including HeLa, A549, and WiDr. Apoptosis and necrosis stimulating potential of mayfly and commercial chitosans were also evaluated on A549 and WiDr cells using acridine orange and propidium iodide dual staining to observe morphological changes in nuclei and thus to reveal the predominant cell death mechanism. The effects of chitosans have varied depending on cell types, concentration, and chitosan derivatives. Mayfly and low MW chitosans had a cytotoxic effect at a concentration of 500 μg mL^-1 on non-cancer cells. At concentrations below this value (250 μg mL^-1), mayfly and commercial chitosans except high MW one exhibited strong inhibitory activity on cancer cells especially A549 and WiDr cells. Mayfly chitosan induced early and late apoptosis in A549 cells, but late apoptosis and necrosis in WiDr cells. This study suggests that dead bodies of mayflies can be used for production of low MW chitosan with anti-proliferative activity.

Hemolysis after mitral valve repair: a report of five cases and literature review

BACKGROUND AND AIM OF THE STUDY

Hemolytic anemia is known to be a rare complication after the prosthetic replacement of the mitral valve, especially in the presence of perivalvular leaks, and even more rarely after mitral valve repair. Following repair, certain distinct patterns of the regurgitant flow disturbances associated with high shear stress are responsible for the hemolysis. Early echocardiographic recognition of these flow patterns may be important to diagnose the condition and may lead to re-repair or replacement of the valve.

METHODS

During the past eight years, mitral valve repair was performed by the present authors in 159 patients, with a prosthetic ring being placed in 130 cases. In five of the patients receiving rings (3.8%) however, intractable hemolytic anemia quickly developed, due to recurrent or residual mitral regurgitation, and this necessitated reoperation.

RESULTS

The valve was replaced in all five patients. One patient died from respiratory and renal failure leading to multiorgan failure. The other four patients were followed up and are currently in good health, with no evidence of hemolysis.

CONCLUSION

Hemolysis frequently occurs immediately or soon after mitral valve repair, and may even appear in mild regurgitation. Thus, following repair with a prosthetic ring it is essential to clearly visualize the dynamic flow patterns postoperatively with transesophageal echocardiography, focusing especially on probable fragmentation, collision and rapid acceleration jets. These findings may lead the surgeon to revise the repair, or to replace the valve.

[Differentiated thyroid cancer]

In the interval 1979-1988, out of 1070 operated goiters 77 malignant thyroid tumors were recorded, 60 of them being differentiated: papillary--32 (53.4%), vesicular--12 (20%), mixed forms--16 (26.7%). The differentiated thyroid carcinomas had peculiar clinical biological and prognostic features and were framed: stage I--60%, stage II--23.4% and state III-IV--16.6%. Only 15 cases presented lymph node metastases. In 16 cases the thyroid tumor was associated with another thyropathy: Hashimoto's thyroiditis--5 cases, Basedow's disease--1 case. The surgical intervention was performed in two times: first total lobectomy or total lobo-isthmectomy [correction of lobioistectomy] with contralateral subtotal exeresis, then total thyroidectomy. It is insisted upon a careful surveillance of postoperative evolution (clinical, biological, scintigraphy) in order to detect the recurrence and apply a proper treatment.

[The "cold" thyroid nodule]

The main problem posed by an (apparent) solitary thyroid nodule is cancer identification, present in about 10% of the nodules excised surgically. This percent might increase to 25-30% in the cold scintigraphic nodules. Therefore, a combination of all the methods for nodule assessment is necessary: anamnesis, physical examination, functional tests, therapeutic test with tyrosine and thyroid imaging, but mainly the intensive active exploration including puncture-biopsy with a fine needle and exeresis with extemporaneous and paraffin morphological checking. Starting from a two decades' experience of a group of endocrinologists, surgeons, anatomo-pathologists and specialists in nuclear medicine, in 2,289 thyropathies operated--of whom 1691 (poly)nodular goitres and 1,190 non-capturing nodules--the authors suggest an investigation algorithm for achieving a differentiated surgery in terms of the pre- and intraoperative morphological findings. This attitude permitted both the improvement of the surgeries of thyroid cancers and the exeresis of benign nodules under low-risk surgical conditions or avoidance of a "non-necessary" surgery.

Renal binding of cadmium in the rat following intragastric exposure

Renal binding of cadmium was compared in groups of rats administered cadmium intragastrically or subcutaneously in doses resulting in similar renal cadmium concentrations. In rats administered cadmium intragastrically the renal concentrations of copper and metallothionein were lower, suggesting disturbance in copper metabolism. These changes were alleviated gradually in the post-exposure period. In experiments with 64Cu it has been shown that intragastric exposure to cadmium reduced copper absorption to about 21% of that in the control rats, thus explaining the poor copper availability for renal binding of cadmium in the form of Cd,Cu-metallothionein. Changes in zinc uptake were less strongly marked and were limited to slight decrease of zinc content in the kidneys.

[Bacterial liver abscess cured by nonsurgical treatment. Comments on 8 cases]

Eight cases (3 children aged 7-15 years and 5 adults aged 16-46 years) of hepatic abscess in whom a cure was obtained by medical therapy are presented. The abscess occurred during septicemia (2 cases), cutaneous staphylococcosis (2 cases) and pyocholecystitis (1 case). In 3 patients the abscess remained cryptogenic. The clinical diagnosis was confirmed by scintigraphy, ultrasonography and in one case by radiography with contrast substance in the abscess. The microorganisms, isolated in 3 patients from the abscess and in one patient from hemoculture, were S. aureus (3 cases) and gram negative bacilli (1 case). The systemic antibiotic therapy consisted in the administration of gentamicin and oxacillin or rifampicin in 4 cases and gentamicin and chloramphenicol or ampicillin and metronidazole in other 4 cases for an average interval of 39 days. The associated local therapy (3 cases) consisted in one or more punctures, followed by the injection of gentamicin.

[Benign solitary thyroid nodule (BSTN)]

Out of a series of 210 patients (193 women and 17 men) with BSTN, 62% presented an warm nodule, 25.2% a hot nodule and 11.9% a cold nodule. The highest incidence of the nodule was noticed round the age of 40-50 years. The most common site was the middle and lower area of the right thyroid lobe. The thyroid scintigram provided orientative data regarding the nature of BSTN, the treatment indication being the surgical intervention. Histopathologically, polymorphic aspects ranging from anizofollicular adenoma, adenomatous proliferations areas and hyperfunctional aspect to degenerative sclerous alterations and lymphoplasmocitary infiltrations were noticed. The current hypotheses regarding the etiopathogeny of nodule forming process are discussed. Based on some data in the literature, we consider the nodularization of the thyroid gland as a reactional zone functional desynchronization in the conditions of some great variations of the iodate intaxe.

[Peculiarities of the surgical treatment of thyrotoxicosis in the aged]

With an increasing frequency, recorded by most of the statistics, the thyrotoxicosis of the aged present themselves, most often, under uncharacteristic clinical aspects, often delusive. Out of a series of 37 thyrotoxic patients (representing 9.2% of all cases of thyrotoxicosis admitted to the Ist Surgical Clinic between 1970 and 1980) in 27 cases we performed a the surgical treatmeat with good immediate and late results. As a preliminary, execepting the endocrine balancing the improvement of the respiratory exchanges, the compensation of the possible heart disturbances and the ensurance of a good hydration and restoring of the nutritional state were followed.

[Cervicomediastinal and thoracic goiters]

Between 1950 and 1979 approximately 2400 patients with thyropathies have been operated in the I-st Surgical Clinic of Jassy. Of these 100 had cervico-mediastinal goiters, of which 79 were of the plunging cervico-mediastinal type, 18 were of the mediastino-cervical type and 3 were mediastinal goiters. The surgical treatment was applied in 98 patients, cervicotomy being sufficient to relieve the symptoms in 92 of the cases. The mixed approach (cervicosternotomy, or cervico-thoracic approach) were necessary in 5 cases, and the thoracic approach was selected in one case with an independent posterior mediastinal goiter. The immediate postoperative evolution, as well as the late evolution was good in most of the cases. Postoperative mortality was of 2 percent.