The effect of SARS-CoV-2 virus on resting-state functional connectivity during adolescence: Investigating brain correlates of psychotic-like experiences and SARS-CoV-2 related inflammation response

We first aimed to investigate resting-state functional connectivity (rs-FC) differences between adolescents exposed to SARS-CoV-2 and healthy controls. Secondly, the moderator effect of PLEs on group differences in rs-FC was examined. Thirdly, brain correlates of inflammation response during acute SARS-CoV-2 infection were investigated. Eighty-two participants aged between 14 and 24 years (SARS-CoV-2 (n = 35), controls (n = 47)) were examined using rs-fMRI. Seed-based rs-FC analysis was performed. The positive subscale of Community Assessment of Psychotic Experiences-42 (CAPE-Pos) was used to measure PLEs. The SARS-CoV-2 group had a lesser rs-FC within sensorimotor network (SMN), central executive network (CEN) and language network (LN), but an increased rs-FC within visual network (VN) compared to controls. No significant differences were detected between the groups regarding CAPE-Pos-score. However, including CAPE-Pos as a covariate, we found increased rs-FC within CEN and SN in SARS-CoV-2 compared to controls. Among the SARS-CoV-2 group, neutrophil/lymphocyte and thrombocyte*neutrophil/lymphocyte ratio was correlated with decreased/increased FC within DMN and SN, and increased FC within CEN. Our results showed rs-FC alterations within the SMN, CEN, LN, and VN among adolescents exposed to SARS-CoV-2. Moreover, changes in rs-FC associated with PLEs existed in these adolescents despite the absence of clinical changes. Furthermore, inflammation response was correlated with alterations in FC within the triple network system.

Validity and reliability of the Turkish version of the Parent Attitudes About Childhood Vaccines (PACV) scale

AIMS

This study aimed to determine the validity and reliability of the Turkish version of the "Parental Attitudes toward Childhood Vaccines" (PACV) scale.

MATERIALS AND METHODS

A two-stage observational validation study was conducted. A back-translation technique was used and then the scale was validated with a sample of 343 parents with children aged 0-72 months. The test-retest method, Cronbach's alpha coefficient, Split-half analysis, and item analysis methods were used to determine the reliability of the scale, factor analyses were run to determine construct validity. Explanatory Factor Analysis and Confirmatory Factor Analysis were applied to assess construct validity.

RESULTS

Cronbach's alpha coefficient was measured as .84. The Spearman-Brown coefficient was .82 and the Guttman Split-half coefficient was .81. According to the item-total correlation and Cronbach's alpha values when the item was deleted, no item was deleted from the scale. The intraclass correlation coefficient between the test-retest measurements was .79. The three-factor structure consisting of 15 items explained 51.6% of the total variance. As a result of the confirmatory factor analysis, a sufficient fit of the model to the model proposed in the original version of the scale was evident (χ²/sd=2.214, RMSEA=.06).

CONCLUSION

The Turkish version of the PACV is a valid and reliable scale and can be used to identify parental attitudes toward childhood vaccines.

Preoperative anxiety and health literacy in patients applying to the anesthesia outpatient clinic

Background

Evaluation of preoperative anxiety and health literacy is important for healthcare professionals to understand the needs and expectations of patients and provide them with the necessary support. The study aimed to evaluate the preoperative anxiety levels of patients who applied to the anesthesia outpatient clinic and its relationship with health literacy.

Methods

A cross-sectional study was conducted on patients who applied to the anesthesia outpatient clinic of Eskişehir Osmangazi University Medical Faculty Hospital in March 2022. The questionnaire form, which was prepared by making use of the literature, was filled in by face-to-face interview method after obtaining the participants’ verbal consent. The 6 item Amsterdam Preoperative Anxiety and Information Scale (APAIS) in which the scores that can be taken range from 6 to 30 and higher score means higher anxiety was used to assess the level of anxiety, and the 16 item European Health Literacy Scale Short Form was used to assess health literacy. Descriptive statistics, Chi-Square test and Logistic Regression analysis were used to analyze the data.

Results

In the study group, 197 (50.3%) were female. Their ages ranged from 18 to 86, with a mean of 45.7 ± 17.2 years. The median (min-max) APAIS score was 15 (6-30). There was a moderate negative correlation between the scores obtained from the APAIS and the European Health Literacy Scale Short Form (r= -0.50, p < 0.01). According to the logistic regression analysis, preoperative anxiety was found to be 1.53 (%95 CI; 1.01-2.30) times higher in women, 3.49 (%95 CI; 1.23-9.94) times higher in those with low family income, and 1.61 (%95 CI; 1.07-2.42) times higher in those with type A personality.

Conclusions

More than half of the patients had preoperative anxiety. The level of preoperative anxiety decreased as the health literacy level increased.

Key messages

Loneliness, internalizing symptoms, and inflammatory markers in adolescent COVID-19 survivors

BACKGROUND

Concerns about the psychiatric sequelae after COVID-19 infection have increased as the pandemic spreads worldwide. The increase in self-isolation during this pandemic period has also revealed the importance of feelings of loneliness. This study aimed to examine the relationship between baseline inflammation levels, internalizing symptoms, and feelings of loneliness in adolescent COVID-19 survivors in the long term.

METHODS

A total of 74 adolescents (41 girls, 55.4%, mean age 14.88) and their parents were included in the study. This cross-sectional study assessed internalizing symptoms via Revised Children's Anxiety and Depression Scale (RCADS) and feelings of loneliness using the UCLA-loneliness scale. Baseline inflammatory markers at COVID-19 diagnosis were collected. Logistic regression analysis was used to determine predictors for depression in adolescents.

RESULTS

The most common disorder was Major Depressive Disorder (MDD) (25.7%), and 33.8% of the adolescents were in the clinical range in at least one internalizing domain. Baseline C-Reactive Protein (CRP) levels correlated weakly with MDD scores. Loneliness scores correlated with all internalizing symptoms, strong association with MDD scores. Loneliness, anxiety, and parental anxiety were associated with an increased likelihood of MDD. Baseline CRP positivity did not predict MDD in adolescent COVID-19 survivors.

CONCLUSIONS

This study indicates that anxiety, loneliness, and parental anxiety play an important role in adolescents' experience of depressive symptoms after COVID-19 infection. Thus, screening parental psychopathology and loneliness in COVID-19 survivors seems to be preventive for adolescent mental health problems.

Correlates of psychotic like experiences (PLEs) during Pandemic: An online study investigating a possible link between the SARS-CoV-2 infection and PLEs among adolescents

BACKGROUND

This study investigated whether SARS-CoV-2 infection, depression, anxiety, sleep problems, cigarette, alcohol, drug usage contribute to psychotic-like experiences (PLEs) among adolescents during the pandemic. We also aimed to explore whether baseline inflammatory markers or the number of SARS-CoV-2-related symptoms are associated with PLEs, and the latter is mediated by internalizing symptoms.

METHODS

Altogether, 684 adolescents aged 12-18 (SARS-CoV-2 group n = 361, control group (CG) n = 323) were recruited. The Community Assessment of Psychic Experiences-42-Positive Dimension (CAPE-Pos), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Pittsburg Sleep Quality Index (PSQI) questionnaires were completed by all volunteers using an online survey. C-reactive Protein and hemogram values, and SARS-CoV-2-related symptoms during the acute infection period were recorded in the SARS-CoV-2 group. Group comparisons, correlations, logistic regression, and bootstrapped mediation analyses were performed.

RESULTS

CAPE-Pos-Frequency/Stress scores were significantly higher, whereas GAD-7-Total and PSQI-Total scores were significantly lower in SARS-CoV-2 than CG. Among the SARS-CoV-2 group, monocyte count and the number of SARS-CoV-2-symptoms were positively correlated with CAPE-Pos-Frequency/Stress scores. Besides SARS-CoV-2, cigarette use, GAD-7, and PHQ-9 scores significantly contributed to the presence of at least one CAPE-Pos "often" or "almost always". PHQ-9 and GAD-7 fully mediated the relationship between the number of SARS-CoV-2 symptoms and CAPE-Pos-Frequency.

CONCLUSIONS

This study is the first to show a possible relationship between SARS-CoV-2 infection and PLEs among adolescents. Depression, anxiety, and cigarette use also contributed to PLEs. The number of SARS-Cov-2-symptoms and PLEs association was fully mediated by internalizing symptoms, but prospective studies will need to confirm this result.

Oleuropein modulates glioblastoma miRNA pattern different from Olea europaea leaf extract

Glioblastoma (GBM) is the most prevalent and deadliest subtype of glioma. Despite current innovations in existing therapeutic modalities, GBM remains incurable, and alternative therapies are required. Previously, we demonstrated that Olea europaea leaf extract (OLE) kills GBM cells by modulating miR-181b, miR-137, miR-153 and Let-7d expression. However, although oleuropein (OL) is the main compound in OLE, its role in the antitumour effect of OLE remains unknown. This study determined the effect of OL on GBM cell line T98G and compared the results with our previous findings regarding the effect of OLE on the same cell line. The antiproliferative activity of OL and its effect on temozolomide (TMZ) response were tested inT98G cells using WST-1 assay. OL inhibition was evaluated using one-way analysis of variance with Tukey's post hoc test. The effect of OL on miR-181b, miR-137, miR-153 and Let-7d expression was assessed using quantitative reverse transcription polymerase chain reaction. Fold differences in expression between untreated, OL or OL + TMZ-treated samples were calculated using 2^-ΔCt method. Significance was evaluated using an independent sample t-test. Treatment with 277.5 and 555 µM OL resulted in 39.51% and 75.40% reductions in T98G cells within 24 h. Coadministration of 325 µM TMZ and 277.5 or 555 µM, OL caused 2.08- and 2.83-fold increases, respectively, in the therapeutic effect of TMZ. OL + TMZ significantly increased microRNA expression, particularly Let-7d, than OLE. In conclusion, OL has an antitumour effect on GBM cells mainly via regulation of Let-7d expression. The present results also indicate other minor compounds in OLE play important anticancer roles.

Effects of adenoid/tonsillectomy on inflammatory response in snoring children with witnessed apnoea

OBJECTIVE

The aim of this study was to investigate the clinical significance of preoperative serum C-reactive protein (CRP), interleukin-6 (IL-6), fetuin-A, cystatin C, adiponectin and tumour necrosis factor-alpha (TNF-α) levels in children with adenoid/tonsillar hypertrophy and compare these results with postoperative values.

STUDY DESIGN

Prospective clinical trial.

SETTING

Single tertiary care centre.

PARTICIPANTS

Thirty-five children (14 boys and 21 girls) participated in this study.

MAIN OUTCOME MEASURES

The operations were performed with the indication of sleep-disordered breathing (SDB). Blood samples were taken preoperatively and at 6 months postoperatively to determine the changes in serum high-sensitivity CRP (hs-CRP), IL-6, fetuin-A, cystatin C, adiponectin and TNF-α levels. Pre- and postoperative values of body weights and heights of the participants were recorded preoperatively and at postoperative 6 months.

RESULTS

Patients underwent adenoidectomy (n = 21) or adenotonsillectomy (n = 21). The mean age at surgery was 8.74 ± 3.33 years (range 3-16 years). Mean serum levels of parameters measured preoperatively and at postoperative 6 months. The observed differences between pre- and postoperative values were statistically significant (P < 0.05), excluding cystatin C levels (P > 0.05).

CONCLUSION

High levels of IL-6, hs-CRP and TNF-α and low levels of fetuin-A in serum might have a clinical significance in patients with sleep-disordered breathing. Levels of cytokines in children with sleep-disordered breathing because of adenotonsillar disease decreased after surgical treatment. The risks of development of cardiovascular disease are decreased in association with lower levels of cytokines, which are also closely associated with many disease states.

Idiopathic infantile arterial calcification: prenatal diagnosis and postnatal presentation

Idiopathic infantile arterial calcification (IIAC) is a rare disease of unknown etiology, which is characterized by arterial calcification. A 29-year-old primigravida at 33 weeks' gestation was referred for further evaluation for polyhydramniosis. An ultrasonographic examination revealed an intrauterine growth restricted fetus, pericardial effusion, increased renal cortical echogenicity with sparing of corticomedullary differentiation, and diffuse arterial calcifications involving the aorta, pulmonary artery, common iliac arteries, renal arteries, and common carotid arteries. At 35 weeks of gestation a cesarean section was performed because of fetal distress. A 1900 g male infant was delivered. Postnatal examination confirmed the diagnosis of IIAC with dysmorphic features (clinodactily and low-set ears) and normal constitutional karyotype. The baby died when he was four months old in the newborn care unit. During routine obstetric ultrasonography, the combination of polyhydramniosis and intrauterine growth restriction may necessitate examination of the major vessels for presumptive a diagnosis of IIAC.

Pattern of pediatric poisoning in the east Karadeniz region between 2002 and 2006: increased suicide poisoning

In the present study, 386 patients with the diagnosis of poisoning admitted to the Pediatric Emergency Unit of Farabi Hospital of Medical Faculty of Karadeniz Technical University between January 2002 and December 2006 were retrospectively evaluated with respect to gender, age, cause of poisoning, type of substance used, route of exposure, reason for the intake, signs and symptoms, time of referral to the hospital, hospitalization period, and prognosis. The age group of most poisoning cases was <5 years of age and constituted 51% (n = 197) of all cases. The main toxic agent was drugs (70.2%), followed by foods (8.8%), rodenticides (7%), insecticides/pesticides (4.9%), and carbon monoxide (4.7%). In childhood poisonings, accidental drug poisoning was frequent in toddlers, whereas suicidal poisoning was frequent in adolescents. The suicidal poisoning rate was 23.8% among all poisoning patients, and 98.9% of these patients were adolescents. The suicidal poisoning rates for males and females were 30% and 70%, respectively. An increase in suicidal and inhalation poisonings was observed when compared with previous studies that have been conducted in the same region. The results of the present study suggest that poisonings still represents an important health problem that could be prevented by safe drug storage at home, as well as parental education on adolescence issues, particularly those regarding females.

An unusual tumour of the cerebellopontine angle

An unusual tumour of the cerebellopontine angle.

OBJECTIVE

To report an extremely rare case of lipoma of the cerebellopontine angle (CPA).

CASE REPORT

A 33-year-old woman presented with vertigo and tinnitus in the left ear. Her physical examination was unremarkable. Audiometric evaluation was normal in both ears. T1-weighted magnetic resonance imaging (MRI) without fat signal suppression revealed a hyperintense lesion of the left CPA. Based on the neuroimaging findings, the diagnosis was left CPA lipoma. The patient was managed conservatively. After 48 months, follow-up MRI revealed no further growth of the lesion and the patient was symptom free.

CONCLUSION

Lipomas of the CPA should be considered in the differential diagnosis of vertigo and tinnitus. Accurate diagnosis by MRI is critical.

Cyclosporine for Behçet's uveitis: is it associated with an increased risk of neurological involvement?

OBJECTIVE

The immunosuppressant cyclosporine is widely used to treat Behçet's disease (BD). The aim of this study was to determine whether cyclosporine increases the risk of neurological involvement in BD.

METHODS

Patient files from the Ophthalmology Department for the period 2000-2005 were screened retrospectively, and the occurrence of neurological involvement and its relationship to ocular severity were evaluated.

RESULTS

A total of 454 patients with BD were seen at the Ophthalmology Department in this period, including 24 who had been referred from the Neurology Department. Excluded from the study were 47 patients who did not have uveitis and 114 patients with an inadequate follow-up. The remaining 269 patients had been treated with either cyclosporine (Group I, n=92), other immunosuppressants (Group II, n=132), or no treatment other than colchicine (Group III, n=45). Patients with neurological symptoms were sent to the Neurology Department for evaluation: 20 from Group I [10 with primary headache, 1 with depression, 1 with sinus thrombosis, and 8 with parenchymal neurological involvement (pNBD)]; 13 from Group II [10 with primary headache, 1 with pre-morbid epilepsy, 1 with sinus thrombosis, and 1 with pNBD]; and 5 from Group III with primary headache. The frequency of pNBD was significantly higher in Group I, and included atypical features such as seizures and MRI lesions as well as the typical symptoms of brainstem involvement and pleocytosis. Eye involvement tended to be more severe in Group I, and the difference remained significant both when milder cases were excluded from the analysis (6 vs. 0; p=0.03) and when severe cases were excluded (p=0.04). pNBD was significantly more frequent in patients on cyclosporine alone than in those receiving cyclosporine plus another agent.

CONCLUSION

In patients with Behçet's uveitis, cyclosporine seems to be associated with an increased risk of developing pNBD, although the reason for this is unknown. A prospective trial is needed to shed light on this problem.

Magnesium, zinc and copper status in osteoporotic, osteopenic and normal post-menopausal women

Serum concentrations of magnesium, zinc and copper were measured in postmenopausal women with osteoporosis (n = 40), osteopenia (n = 40) or normal bone mineral density (n = 40) as classified on the basis of the T-score of the femur neck and dual energy X-ray absorptiometry results. Mean concentrations of magnesium and zinc were significantly lower in osteoporotic women than in both osteopenic women and normal women. In addition, magnesium and zinc concentrations in osteopenic women were significantly lower than in normal women. There were no statistically significant differences observed between the osteopenic, osteoporotic and control groups with respect to copper levels. The clinical significance of these changes needs further elucidation, but trace element supplementation, especially with magnesium and zinc and perhaps copper, may have beneficial effects on bone density.

Clinical characteristics and course of spinal cord involvement in Behçet's disease

Parenchymal neurological involvement in Behçet's disease (p-NBD) usually presents with a brainstem syndrome; occasionally spinal cord may also be involved. Files of patients with Behçet's disease and spinal cord involvement were reviewed retrospectively, in comparison with other types of p-NBD. Amongst 216 patients with p-NBD, 24 had spinal cord involvement (11%). Most commonly patients presented with sensory-motor symptoms, sphincter and/or sexual dysfunction evolving over days. Four of 10 patients showed single or multiple cervical and/or dorsal lesions on spinal MRI's and one showed dorsal atrophy. Although the clinical picture was variable, it tended to be severe; seven cases had primary progressive course, 11 cases had a secondary progressive course after initial attack(s), four had attacks with severe residual sequela and two had improvement after attacks. After a median follow-up period of 67 months, eight were independent and 14 were dead or dependent, whereas amongst the remaining patients with p-NBD, 113 patients were independent and 56 patients were dead or dependent (P < 0.05). Our study suggests that spinal cord involvement has even worse prognosis compared with other types of p-NBD. Therefore, recognition of spinal cord involvement in Behçet's patients should prompt early vigorous treatment.

The effects of HEMA-monomer and air atmosphere treatment of glass fibre on the transverse strength of a provisional fixed partial denture resin

This study focused on some mechanical properties such as the transverse strength, the maximal deflection, and the modulus of elasticity of resin reinforced with two different types of agents-treated and with untreated glass fibre, and without fibre. A Teflon mould was used to prepare six groups of specimens. Two different types of chemical modification agents, hydroxyethyl-methacrylate (HEMA)-monomer and air atmosphere were applied to create hydrophilic surfaces on the glass fibres. The flow rate was kept at two different levels, 25 and 60 mL min-1. The discharge powers of the surface treatment process were 15 or 20 W. The fibres were exposed to glow discharge conditions for the periods of 10 or 15 min. Without fibre specimens were the control group. The provisional resin was same in all groups. All the specimens were subjected to transverse testing with a cross-head speed of 5 mm min-1. The three-point load test was used to record the load of the fracture for each specimens. The Kruskal-Wallis analysis of variance was used to compare the transverse strength, the maximal deflection and the modulus of elasticity. The differences in the transverse strength and the maximal deflection between the six groups were found statistically significant but the modulus of elasticity was not statistically significant. The transverse strength of HEMA-monomer (group A) was shown the highest value (66.3 MPa). For without-fibre group, the value was 52.9 MPa. This difference was statistically significant when the Mann-Whitney U-test was used for comparing. Repairing or remaking provisional restorations can be a time-consuming endeavour. The added strength of the polymethyl methacrylate with the fibre can reduce clinical failures of provisional fixed partial dentures. The surface treatment process was increased the transverse strength and the maximal deflection. The clinical implication of chemical modification agents-coated fibres is reduced incidence of fixed provisional restoration failure.

The pelvic external fixation: the mid-term results of 41 patients treated with a newly designed fixator

The purpose of this study was to evaluate the clinical and radiological results of unstable pelvic fractures treated with a new external fixation device. Between May 1992 and May 1998, 43 patients with unstable pelvic fractures were treated with a new anterior pelvic external fixator. Two died, and therefore 41 patients' results were evaluated. There were 29 men and 12 women, and their average age was 34 years (range 12-70 years). Traffic accidents accounted for 34 injuries. Three patients fell from a height, 3 were injured in industrial accidents, and 1 was hit by a train. According to the Tile classification, there were 24 type B pelvic injuries and 17 type C. Associated injuries were observed in 21 patients. A considerable reduction of the pelvic pain was noted after application of the fixator in all patients. Excessive blood transfusion was not required in any patient. The average follow-up was 24 months (range 12-50 months). Clinical results at final evaluation were good according to the criteria of Matta and Saucedo in 34 patients and poor in 7. In conclusion, the new pelvic external fixator is effective, safe, and easy to apply in the treatment of unstable pelvic fractures. The fixator can be used alone in patients with type B pelvic injuries such as open book and lateral compression. However, it does not provide sufficient stability for severely displaced type C injuries when applied alone. Nevertheless, it may be helpful for fixing type C injuries like a posterior iliac fracture without dislocation of the sacroiliac joint.

The de Barsy syndrome

We report a child with de Barsy syndrome, which is a very rare, genetically transmitted clinical entity associated with mental and growth retardation, severe cutis laxa, joint laxity and various ocular and skeletal system findings. The patient was operated to treat her orthopedic disabilities. Typical findings of this case with eight-year follow-up beginning from birth are described and compared with previously reported cases. The main aim of this paper was to describe the diagnostic and therapeutic difficulties of this rarely encountered syndrome.

Hemodynamic monitoring of the contralateral testis during unilateral testicular torsion describes the mechanism of damage

Contralateral testicular perfusion during unilateral testicular torsion was evaluated using simultaneous blood flow and O2 content determinations. Two groups, each consisting of 7 rats, were studied. Sham operation or 720 degrees clockwise twisting was performed on the left testes, and blood flow, O2 content and temperatures were monitored in the right testes for 180 min. An ultrasonic perivascular Doppler flowmeter system, an electronic thermometer and an O2 electrode were used for the monitoring. The contralateral testicular blood flow and relative O2 contents were stable in the control group. However, the initial and 180 min blood flow values decreased from 0.21 +/- 0.04 to 0.11 +/- 0.02 ml/min (p < 0.001), and the O2 contents from 0.857 +/- 0.123 to 0.319 +/- 0.037 (1.0 corresponds to 19.6 mm Hg pO2, p < 0.05) in the experimental group. Unilateral testicular torsion decreases the blood flow and O2 content of the contralateral testis. The contralateral testicular injury encountered following unilateral testicular torsion might result from hypoxia following the decrease in blood flow.

Preliminary traction as a single determinant of avascular necrosis in developmental dislocation of the hip

The role of preliminary traction before closed reduction in the treatment of developmental dysplasia of the hip has been questioned by many authors lately. However, the studies advocating or opposing the use of this treatment modality include several other parameters besides traction. Thus, it is unclear whether the affection is the result of preliminary traction or concurrent variables such as the "human position." This study aimed to put forward the effect of preliminary traction as a single determinant of avascular necrosis. We had two groups of patients who had developmental dislocation of the hip. The first group consisted of 52 patients treated with preliminary traction before closed reduction and the other group comprised 40 patients treated with closed reduction without preliminary traction. Both groups were similar in age, gender, side, level of dislocation, and method and duration of immobilization. Three patients from the first group developed avascular necrosis, which was not statistically significant. Preliminary traction did not affect the rate of avascular necrosis.

Evaluation of 99mTc labelled poly lactic acid microspheres for diagnostic radioembolization

Radioembolization is used in diagnostic imaging of the lungs and for radioembolization therapy of hepatic tumours. Presently, 99mTc labelled macroaggregates or microspheres of human serum albumin (HAM) are used for this purpose. Poly lactic acid (PLA) is biodegradable, like HAM, and, unlike HAM, is not a blood product. The aim of the present study was to evaluate the uptake and biodegradation of PLA microspheres in lungs. PLA (MW = 48720 Da) microspheres of 1.0-100 microm (mean = 39.5 microm) in diameter were prepared by solvent evaporation from methylene chloride. They were labelled with 99mTc by stannous chloride reduction at pH 3, with an efficiency of 98% and a stability of 96% at 24 h. For biodistribution studies, 15 mice were i.v. injected with 20 microCi 99mTc-PLA microspheres in 0.1 ml and sacrificed at 15 min, 1, 3, 6 and 24 h (three at each time point). All the organs were removed, weighed and counted against a standard prepared from 1/100 dilution of the injected radioactivity. Some mice were similarly injected and sacrificed at 30 min, 15 and 30 days. The lungs were removed and frozen, and 10 microm sections were obtained, stained with haemotoxylin and eosin and examined under a light microscope. Five rabbits were i.v. injected with 1 mCi of 99mTc-PLA microspheres. Scintigrams were obtained at various intervals up to 24 h. In mice, the lung uptake was significant at 30 min-1h post-injection. In rabbits, the lungs were the only organs visualized up to 24 h. Microscopic examination of tissue sections demonstrated slow biodegradation of PLA particles. In conclusion; (1) The high lung uptake obtained in mice and rabbits indicates the suitability of PLA microspheres for lung imaging, and (2) although the slow biodegradation rate might be a disadvantage in patients with lung disorders in diagnostic studies, it may be an advantage in therapeutic applications with radionuclides which have long physical half lives.

Estrogen and progesterone receptors in the peripheral giant cell granulomas of the oral cavity

Peripheral giant cell granulomas are common proliferative lesions of the oral cavity with a predilection for females. In this study, the presence of estrogen and progesterone receptors in 26 peripheral giant cell granuloma cases were studied utilizing the immunoperoxidase technique. In fourteen cases, estrogen receptor positivity was found in stromal cells. In ten of these, osteoclast-type giant cells also exhibited estrogen receptor immunostaining. Progesterone receptor expression was not detected. It was concluded that the cells forming peripheral giant cell granuloma are potential targets for estrogens and that these lesions might be conditioned by sex hormones.

A study of macromolecular diffusion through native porcine mucus

A diffusion chamber technique based on time-lag analysis for the estimation of effective diffusion coefficients of radiolabelled macromolecules of varying molecular weights through native mucus gel is reported. For all solutes studied, a reduction in effective diffusion coefficients was observed with a retardation of solute flux in both aqueous and mucus layers. Over the molecular weight range of solutes investigated (126-186,000 Daltons), a consistent effect of molecular weight was evident with regard to the retarding effect of mucus. No apparent or absolute molecular weight cut-off for macromolecular transfer was exhibited. However, at high molecular weights (greater than 30,000 Daltons) the retardation was greatly enhanced. The results confirm that mucus can be regarded as a gel with finite pores, but that it does not constitute an absolute barrier to even high molecular weight solutes.

Evaluation of 99mTc labelled monodisperse polystyrene/polyacrylate latex particles for the study of colon transit and morphology

A new radiopharmaceutical for the study of colon transit time and morphology is proposed. Polymeric latexes, as monodisperse polymeric spheres (1-10 microns in diameter), were prepared by a coaxial dispersion polymerization of styrene and dimethylaminoethyl-methacrylate (DMAEA). They were labelled with 99mTc by the tin reduction method with high efficiency (greater than 99%). The label was stable up to 48 h at pH values of 1-8 at room temperature. Scintigrams obtained in rabbits after oral administration of 37 MBq of 99mTc-latex particles showed that greater than 90% of the dose remained in the gastrointestinal tract. The cumulative faecal excretion was 8.6 +/- 6.7 in 24 h and 21.3 +/- 13.8% in 48 h. In human studies the colon was well visualized at 4 h. The thyroid and the urinary bladder were not detected on scintigrams, indicating the stability of the label in vivo. Our results demonstrated that the radiopharmaceutical developed in the present study was ideal for the intended purpose.

Blood plasma proteins on polyurethane and alkylsiloxane plasma-treated polyurethane surfaces. Dynamic approach by stimulus-response technique. Part 2. Evaluation of adsorption data by moment technique

In this study, interactions of blood proteins (i.e. albumin and fibrinogen) with polyurethane biomaterial surfaces were investigated in an in vitro bead column test circuit using a stimulus-response technique. The dynamic sorption process of radiolabelled proteins on the surfaces was followed by detecting the radioactivity at the exit stream of the column, which was the response of a pulse stimulus at the inlet. The mathematical model was described and solved using 'parameter estimation by cybernetic moment technique', and the adsorption rate constants of plasma proteins on different biomaterial surfaces were calculated. By evaluation of the response curves with standard and cybernetic moment techniques, the following results were obtained. Albumin and fibrinogen adsorption is competitive, and the competition is strongly dependent upon the surface characteristics of the biomaterial. Preadsorption or preferential adsorption of albumin decreases the fibrinogen adsorption, and therefore increases the biocompatibility of material surface. Adsorption of blood plasma proteins are irreversible. The moment technique can also be used for the evaluation of stimulus-response data of biological systems, to determine the process parameters.

99mTc-MDP adsorption of some dental alloys with varying surface roughness: effect of oral environment

The purpose of this study was to measure the surface characteristics of some dental alloys by 99mTc-MDP adsorption and to investigate the effect of oral environment on 99mTc-MDP adsorption. Sample discs of five different dental alloys were prepared. The surfaces were sandblasted, ground with sandpaper, polished and electrolysed in succession. The surface roughness of each disc was measured by the use of a profilometre. Contact angles (theta) of the surfaces were also measured. 99mTc-MDP adsorption of the discs was determined both prior to and after 2 h of exposure to the oral environment. Our results indicated that the discs sandblasted and electrolysed had the maximum surface roughness and those polished the minimum surface roughness. The 99mTc-MDP adsorption showed variation according to the type of alloy used and its surface roughness prior to exposure to the oral environment. After exposure 99mTc-MDP adsorption was essentially the same for all the alloys.

Preparation of polyethyleneglycol (PEG) coatings for microencapsulation of charcoal

Polyethyleneglycols (PEGs) with their high solubility in water cannot normally be used as a coating material in aqueous solutions such as blood. A gamma-radiation procedure was therefore applied after coating charcoal granules with PEG in a non-aqueous phase, and an 80-90% insoluble polymer matrix on charcoal was obtained. PEGs with different molecular weights from 4000 to 300,000 were used for coating. The performance of this system was determined by using several test solutes, namely creatinine, uric acid, and vitamin B-12. It was observed that the pore size and structure of these membranes can be adjusted by changing the irradiation time and by using PEGs with different molecular weights. Thus, very high mass transfer rates can be achieved.