Forensic Engineering of Advanced Polymeric Materials-Part VII: Degradation of Biopolymer Welded Joints.

Welding technology may be considered as a promising processing method for the formation of packaging products from biopolymers. However, the welding processes used can change the properties of the polymer materials, especially in the region of the weld. In this contribution, the impact of the welding process on the structure and properties of biopolymer welds and their ability to undergo hydrolytic degradation will be discussed. Samples for the study were made from polylactide (PLA) and poly(3-hydroxyalkanoate) (PHA) biopolymers which were welded using two methods: ultrasonic and heated tool welding. Differential scanning calorimetry (DSC) analysis showed slight changes in the thermal properties of the samples resulting from the processing and welding method used. The results of hydrolytic degradation indicated that welds of selected biopolymers started to degrade faster than unwelded parts of the samples. The structure of degradation products at the molecular level was confirmed using mass spectrometry. It was found that hydrolysis of the PLA and PHA welds occurs via the random ester bond cleavage and leads to the formation of PLA and PHA oligomers terminated by hydroxyl and carboxyl end groups, similarly to as previously observed for unwelded PLA and PHA-based materials.

Prediction studies of environment-friendly biodegradable polymeric packaging based on PLA. Influence of specimens' thickness on the hydrolytic degradation profile.

Application of new biodegradable polymer packaging based on polylactide (PLA), susceptible to organic recycling, can help in the waste reduction in landfills. In this paper, the results of the study on abiotic degradation of PLA and its blend containing 15 mol% of poly[(R,S)-3-hydroxybutyrate], as a model for the first step of organic recycling were presented. The samples used for this study have different shapes and thicknesses: rigid films and cuboid-bars. Particular emphasis was placed on determining the pattern of degradation products released into the medium. Originally, the results of present study revealed that the application of electrospray ionization mass spectrometry supported by high performance liquid chromatography allowed envisaging the differences in the degradation products pattern released from the studied PLA-based samples differing in thickness. The significant differences in degradation products pattern were predominately observed in the first steps of incubation process and are caused by an autocatalytic effect, which occurs mainly during degradation of the large size PLA samples. Although, the thickness of PLA-based packaging changes the degradation product patterns, however this does not increase the total amounts of acids released to the medium. Thus, it may be concluded that thickness should not affect significantly organic recycling of the packaging.

Bone mass in chronic renal insufficiency patients treated with continuous ambulatory peritoneal dialysis.

Chronic renal failure (CRF) causes deterioration of the fluid, electrolyte, and acid-base balances, azotemia, and impairment of the structure and function of many systems. In the skeletal system, CRF changes both the quality and quantity of the bone through its multifactorial influence on bone metabolism, leading to osteopenia, osteoporosis, and increased risk of fracture. The aim of the present study was to work up the quickest and most sensitive schedule for detecting osteoporosis in chronic renal insufficiency patients treated with CAPD. Thirty-seven uremic patients were included in the study. Bone mineral density was measured by dual-energy x-ray absorptiometry in lumbar spine, femoral neck, forearm (33% distal and ultradistal sites), and total body. Analyzing all five sites, we made the assessment that the prevalence of osteoporosis in our group of patients reached 48.6%. If only one site was evaluated, the ultradistal part of forearm yielded the highest frequency of diagnosis of osteoporosis (37.8%). Next came the femoral neck and total body (21.6% each). When the two sites in the forearm were taken into account together, the incidence of osteoporosis reached 40.5%. We conclude that the quickest and most sensitive method of detecting osteoporosis in CAPD patients is to measure bone mass in both forearm sites (33% distal and ultradistal), then in the femoral neck.

[Estimation of efficacy of the octreotide LAR administration in the patients with somatotropinoma]. / Ocena skutecznosci stosowania oktreotydu LAR u pacjentów z guzami przysadki typu somatotropinoma.

Acromegaly is caused by excessive secretion of growth hormone by a hypophyseal adenoma type of somatotropinoma. IGF-I is formed in the liver and mediates most biological actions of GH. Treatment of adenomas, which secrete GH, involves pharmacotherapy followed by surgery. Modern pharmacotherapy leaning is based on somatostatin analogues (factor restrictive secretion GH): octreotide, octreotide LAR and lanreotide. The aim of our study was estimation of efficiency of octreotide LAR in the patients with somatotropinoma prepared to neurosurgery intervention. We examined 16 patients (10 of women and 6 men) with the features of active acromegaly. In all cases the increased concentration of HGH and IGF-I were observed. The presence of pituitary adenoma in all patients was confirmed by MRI. The patients were treated with octreotide LAR monthly in dose 20 mg and 30 mg respectively. Before and after application of somatostatin analogues the concentration HGH, IGF-I, PRL in serum were marked. The concentration of GH before octreotide LAR therapy in all patients increased remarkable and ranged from 15.6 to 78.6 ng/ml, mean: 31.20 +/- 16.84 (norm: 0-10 ng/ml), also, in all cases the serum IGF-I level was increased and ranged from 451 to 1107.6 ng/ml, mean: 801.75 +/- 207.82 (norm: 100-400 ng/ml). The prolactin concentration ranged from 7.4 to 49.9 ng/ml, mean: 22.8 +/- 13.7 (norm: 2-20 ng/ml) and in 8 (50%) cases the increased of PRL concentration in serum was observed. After the administration of octreotide LAR the level of: GH [mean: 12.99 +/- 17.16 ng/ml (p < 0.001)], of IGF-I [mean 422.8 +/- 229 ng ml (p < 0.01)] statistical important decreased and prolactin in 8 with increased concentration [mean: 12.45 +/- 5.57 (p < 0.01)] were observed. Long acting somatostatin analogues--octreotide LAR is particular efficient in lowering of growth hormone and IGF-I in patients with somatotropinoma and shows efficiency in normalization of increased prolactin concentration. Because of extreme effectiveness of octreotide LAR, it should be used the routine treatment at the patients suffering from active acromegaly and preparing to neurosurgical treatment.

Novel synthesis of functionalized poly(3-hydroxybutanoic acid) and its copolymers.

Novel feasibility of fuctionalized poly(3-hydroxybutanoic acid), PHB, and its copolymers synthesis via ring-opening of beta-butyrolactone (ROP) mediated by activated anionic initiators or enzymes in vitro is presented. Using these new synthetic approaches, PHB with defined chemical structure of the end groups as well as block, graft and random copolymers have been obtained and characterized by IR, NMR, ESI-MS and GPC techniques. The relationship between the structure and properties of the novel polymeric materials prepared is discussed.

[Bone mineral density in primary hyperparathyroidism]. / Gestosc mineralna kosci w pierwotnej nadczynnosci przytarczyc.

UNLABELLED: Skeletal complications of advanced hyperparathyroidism include clinically bone pains, muscle weakness, bone deformities and fractures. X-ray studies reveal subperiosteal bone resorption, atrophy of the cortex of long bones, cysts, brown tumours and calcifications of soft tissues; these changes appear in the late period of the disease. In recent onset of hyperparathyroidism bone changes may be detected by X-ray absorptiometry. Thus the aim of our study was to evaluate bone mineral density with the use of dual energy X-ray absorptiometry (DEXA) at two sites: in lumbar vertebral bodies consisting mainly of the trabecular bone and in 1/3 distal part of the radius composed predominantly of the cortical bone. Twenty-three patients with primary hyperparathyroidism were included in our study. Hypercalcemia (ionized calcium above 5.4 mg/100 ml, total calcium above 10.6 mg/100 ml) and increased serum PTH, above 100 pg/ml, were detected in all patients. Isotope scintigraphy using 99mTc-MIBI revealed the presence of a parathyroid adenoma; this was confirmed at surgery and histopathologically. In bone densitometry we found greatly reduced bone mineral density (BMD) in 1/3 distal part of the radius amounting to 66.8 +/- 12.0% of the age-matched range and markedly smaller bone loss in lumbar spine, BMD was 91.7 +/- 14.6%. In 10 patients control densitometry, performed 6-24 months after parathyroid adenomectomy, revealed a marked 10 to 22% increase in bone density of lumbar vertebral bodies in the first year. BMD of the 1/3 distal part of the radius increased to a smaller degree 6.3% per year. CONCLUSIONS: 1. Bone densitometry in primary hyperparathyroidism reveals pronounced decrease in bone mineral density in the 1/3 distal part of the radius and much smaller decrease of the lumbar spine density. 2. Parathyroid adenomectomy leads to a rapid increase in density of the trabecular bone L1-L4 vertebral bodies and much smaller increase in the cortical bone of the radius. 3. Pronounced differences in bone mineral density of cortical bone and trabecular bone surpassing 20% are characteristic of hyperparathyroidism as they do not occur in other types of osteoporosis.

[Markers of bone formation and resorption in primary and secondary hyperparathyroidism]. / Markery tworzenia i resorpcji kosci w pierwotnej i wtórnej nadczynnosci przytarczyc.

Hyperparathyroidism, both primary and secondary in chronic renal failure, leads to pathologic changes in the bones. Newly introduced markers of bone metabolism enable to biochemically detect and evaluate these changes. The aim of our studies was to perform determinations of serum osteocalcin as a marker of bone formation, and C-terminal telopeptide of collagen I (ICTP) as a marker of bone resorption in patients with excessive secretion of parathyroid hormone (PTH). Our studies comprised of 15 patients with primary and 24 patients with secondary hyperparathydroidism. In all patients serum PTH, osteocalcin and ICTP were detected by radioimmunoassay; the correlations between PTH and osteocalcin as well as between PTH and ICTP were also performed. Serum PTH was elevated in both, primary and secondary hyperparathyroidism. In primary hyperparathyroidism serum osteocalcin was moderately or definitely elevated, similarly serum ICTP was high. Following surgical removal of a parathyroid adenoma, concomitantly with a drop in serum PTH there was a rapid normalization of serum osteocalcin and ICTP. Secondary hyperparathyroidism in uraemia was characterised by markedly elevated serum osteocalcin and ICTP which surpassed the concentration of these markers in primary hyperparathyroidism. There was a positive correlation between serum PTH and osteocalcin levels, and a lower correlation between PTH and ICTP. From our studies it is concluded that excessive secretion of PTH in primary and secondary hyperparathyroidism stimulates bone formation and to higher degree--bone resorption.

[Primary hyperparathyroidism--diagnostic problems]. / Pierwotna nadczynnosc przytarczyc--problemy diagnostyczne.

Parathyroid imaging with 99m Tc-MIBI, introduced at the beginning of the 90's seems to be a promising method for parathyroid adenomas localization. The aim of the study was to assess the efficacy of parathyroid imaging with 99m Tc-MIBI for preoperative localization of parathyroid adenomas and to compare that method with the high-resolution ultrasonography. Thirteen patients with primary hyperparathyroidism of duration from 2 to 25 years were included in the study. The presence of parathyroid adenomas was confirmed by histopathology in all patients. The sensitivity for scintigraphy and ultrasonography was 92.8% and 78.5%, the number of false positive results was 0 and 2 and false negative-0 and 1, respectively. Parathyroid imaging with 99m Tc-MIBI is a useful method for parathyroid adenomas localization, and in contrast to ultrasonography its sensitivity does not decrease if a parathyroid adenoma is located ectopically. Nevertheless, because of the greater accessibility, lower costs and its simplicity ultrasonography should be used as a screening modality for parathyroid adenoma localization.

[Comparison of calcitonin tolerance after intramuscular or intranasal administration in treatment for postmenopausal osteoporosis]. / Porównanie tolerancji kalcytoniny podawanej domiesniowo lub donosowo w leczeniu osteoporozy pomenopauzainej.

The aim of the study was to compare the tolerance of synthetic salmon calcitonin applied in two different ways, intramuscularly or intranasally, in 50 patients with postmenopausal osteoporosis with bone fractures. Thirty patients were treated with calcitonin in intramuscular or subcutaneous injections, whereas in 20 cases calcitonin was applied in nasal spray. In the first group several side effects were observed, like nausea, vomiting, abdominal pains, skin rush, headaches, dropping blood pressure, symptoms of bronchial spasm. Finally in 13 cases it was necessary to stop calcitonin therapy. On the other hand the patients receiving calcitonin in nasal spray did not manifest any severe side effects.

[Isolation and purification of transcortin (cortisol binding globulin--CBG) using two-step chromatography]. / Izolacja i oczyszczanie transcortyny globuliny wiazacej kortyzol--(CBG)--za pomoca dwustopniowej chromatografii.

The isolation of cortisol and progesterone binding globulin (CBG) from pregnant women serum was performed using affinity and hydrophobic chromatography. The purity and specificity of isolated transcortin was tested by agarose gel electrophoresis using racket and cross immunoelectrophoresis and specific CBG antibodies. High purity and immunoreactivity of the isolated globulin destitute of other proteins contamination, were obtained.

Prevalence of beta allele of the insulin gene in type II diabetes mellitus.

Fifty-two patients and 36 controls were compared in a search for insulin gene variants among type II diabetic patients with fasting hyperinsulinemia (above 90 microU/ml) and a fasting C-peptide to insulin molar ratio between 1.11 and 1.50. Alpha and beta alleles of the insulin gene were characterized by restriction analysis of polymerase chain reaction (PCR) products and direct sequencing. The more frequent occurrence of the alpha allele of the insulin gene within the control population as compared with a prevalence of the beta allele in the diabetic patients (P, 0.05) was observed. The beta allele, usually described as the rare allele, seems to be associated with the disease.

[Outcome of treating hypothyroidism with thyreoideum]. / Wyniki leczenia niedoczynnosci tarczycy preparatem thyreoideum.

The results of hypothyreosis therapy with thyroideum (dried thyroid gland) were assessed in 40 patients. The study aimed at establishing proper dosage and assaying blood serum T4, T3, and TSH levels. Daily dose of 1 tablet (0.2 mg of iodine) improved clinical status but did not cover the daily requirement of the body for thyroid hormones. An increase in daily dose to 2 tablets (0.4 mg of iodine) produced nearly complete compensation of hypothyreosis. However, such a daily dose was often associated with adverse reactions, especially in patients with arterial hypertension or atherosclerosis. Thyroid hormones assay has shown that dried thyroid gland administered in daily dose of 0.4 mg normalizes serum T3 levels whereas serum T3 levels remained constantly low, and TSH increased as in non-treated disease. An increase of the daily dose to 0.6 mg of iodine produces excessive increase in serum T3 levels with clinical symptoms of T3 toxicity.

[Monitoring of treatment for hypothyroidism with L-thyroxine]. / Monitorowana terapia niedoczynnosci tarczycy L-tyroksyna.

The study was aimed at the evaluation of treatment of hypothyroidism with L-thyroxine administration monitored by the determination of T3 and T4 concentrations. The investigations were carried out in a group of 57 patients with hypothyroidism including 37 patients with autoimmune etiology of hypothyroidism, 12 patients after strumectomy and 8 patients after treatment with 131J. The administration of L-thyroxine at a dose of 2 micrograms/kg/day effectively eradicated all symptoms of the disease and led to the normalization of blood serum T3 and T4 values in the majority of patients with autoimmune hypothyroidism. So the majority of women required the daily dose of L-thyroxine of 100-150 micrograms, and the majority of men 125-175 micrograms. Lower dosage of L-thyroxine (50-100 micrograms daily) was required to attain euthyroid state in some patients with postoperative or postradiation hypothyroidism. Monitoring of the therapy by the determination of blood serum T3 and T4 concentrations greatly facilitated the proper choice of the therapeutic dose of L-thyroxine as the return of the thyroid hormone concentrations to normal usually brought about the complete remission of symptoms of the disease. The exception from this rule was only in the case of patients with arterial hypertension and coronary disease in whom, because of the side-effects, lower dosage of L-thyroxine (usually 50 micrograms daily) must have been applied to attain the optimal improvement. The treatment with L-thyroxine caused much less side-effects as compared to the therapy using the dessicated thyroid preparations (Thyroideum).

[Investigation of the insulin gene by the amplification method in vitro]. / Badania genu insuliny metoda amplifikacji in vitro.

Forty one patients with familial non-insulin-dependent diabetes (type 2) were included into the study. The fragment of insulin gene including the sequences coding for beta chain and part of C-peptide as well as 5'untranslated region was amplified in vitro by using the polymerase chain reaction. The digestion of the fragments by using the restriction enzyme Pst I followed by electrophoretic separation allowed to recognize the alpha and beta alleles of insulin gene. The investigations have shown that the beta allele occurs more frequently in diabetic patients than in healthy control subjects (P < 0.05).