Exosome-mediated tumor metastasis: Biology, molecular targets and immuno-therapeutic options

Small extracellular vesicles called exosomes play a crucial part in promoting intercellular communication. They act as intermediaries for the exchange of bioactive chemicals between cells, released into the extracellular milieu by a variety of cell types. Within the context of cancer progression, metastasis is a complex process that plays a significant role in the spread of malignant cells from their main site of origin to distant anatomical locations. This complex process plays a key role in the domain of cancer-related deaths. In summary, the trajectory of current research in the field of exosome-mediated metastasis is characterized by its unrelenting quest for more profound understanding of the molecular nuances, the development of innovative diagnostic tools and therapeutic approaches, and the unwavering dedication to transforming these discoveries into revolutionary clinical applications. This unrelenting pursuit represents a shared desire to improve the prognosis for individuals suffering from metastatic cancer and to nudge the treatment paradigm in the direction of more effective and customized interventions.

Retrieval of long DNA reads from herbarium specimens

High-throughput sequencing of herbarium specimens' DNA with short-read platforms has helped explore many biological questions. Here, for the first time, we investigate the potential of using herbarium specimens as a resource for long-read DNA sequencing technologies. We use target capture of 48 low-copy nuclear loci in 12 herbarium specimens of Silene as a basis for long-read sequencing using SMRT PacBio Sequel. The samples were collected between 1932 and 2019. A simple optimization of size selection protocol enabled the retrieval of both long DNA fragments (>1 kb) and long on-target reads for nine of them. The limited sampling size does not enable statistical evaluation of the influence of specimen age to the DNA fragmentation, but our results confirm that younger samples, that is, collected after 1990, are less fragmented and have better sequencing success than specimens collected before this date. Specimens collected between 1990 and 2019 yield between 167 and 3403 on-target reads > 1 kb. They enabled recovering between 34 loci and 48 (i.e. all loci recovered). Three samples from specimens collected before 1990 did not yield on-target reads > 1 kb. The four other samples collected before this date yielded up to 144 reads and recovered up to 25 loci. Young herbarium specimens seem promising for long-read sequencing. However, older ones have partly failed. Further exploration would be necessary to statistically test and understand the potential of older material in the quest for long reads. We would encourage greatly expanding the sampling size and comparing different taxonomic groups.

Global prevalence of urinary tract infection in pregnant mothers: a systematic review and meta-analysis

OBJECTIVE

Urinary tract infection (UTI) is a prevalent infection during pregnancy that can lead to complications for both the mother and the foetus. The objective of this systematic review and meta-analysis is to determine the global prevalence of UTIs (both symptomatic and asymptomatic) during pregnancy, based on previous studies in this area. Furthermore, this study aims to identify any factors that contribute to heterogeneity in the prevalence of UTIs during pregnancy.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

This study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines on August 8, 2022. To conduct the systematic review and meta-analysis, a search was performed using the keywords "urinary tract system", "UTI", "pregnancy", and "gestation" was performed in several databases, including Web of Science (WoS), PubMed, Scopus, ScienceDirect, Embase, and Google Scholar, without a time limit until September 18, 2022. The analysis was performed using a random-effects model, and the heterogeneity of the studies was assessed using the I2 index. The Comprehensive Meta-Analysis software (Version 2) was used for data analysis.

RESULTS

The systematic review and meta-analysis of 27 studies, which included a total of 30,641 pregnant women, showed an overall prevalence of UTI (both symptomatic and asymptomatic) to be 23.9% (95% confidence interval: 16.2-33.8). Meta-regression analysis was conducted to examine the impact of two factors, namely study sample size and study year, on the heterogeneity of the meta-analysis. The results revealed that an increase in sample size, and the study year was associated with a decrease in the prevalence of UTI in pregnant women (P < 0.05).

CONCLUSION

The results of our study indicate a global prevalence of UTI in pregnant women to be 23.9%. Therefore, it is recommended that all pregnant women undergo regular UTI screening tests and receive prompt treatment if diagnosed with UTI. Early detection and treatment of UTI during pregnancy are crucial to prevent complications that may affect the health of both the mother and the foetus.

Saliency-Driven Hand Gesture Recognition Incorporating Histogram of Oriented Gradients (HOG) and Deep Learning

Hand gesture recognition is a vital means of communication to convey information between humans and machines. We propose a novel model for hand gesture recognition based on computer vision methods and compare results based on images with complex scenes. While extracting skin color information is an efficient method to determine hand regions, complicated image backgrounds adversely affect recognizing the exact area of the hand shape. Some valuable features like saliency maps, histogram of oriented gradients (HOG), Canny edge detection, and skin color help us maximize the accuracy of hand shape recognition. Considering these features, we proposed an efficient hand posture detection model that improves the test accuracy results to over 99% on the NUS Hand Posture Dataset II and more than 97% on the hand gesture dataset with different challenging backgrounds. In addition, we added noise to around 60% of our datasets. Replicating our experiment, we achieved more than 98% and nearly 97% accuracy on NUS and hand gesture datasets, respectively. Experiments illustrate that the saliency method with HOG has stable performance for a wide range of images with complex backgrounds having varied hand colors and sizes.

Cloning, overexpression, and structural characterization of a novel archaeal thermostable neopullulanase from Desulfurococcus mucosus DSM 2162

The main purpose of the present study is to introduce the biochemical characteristics of the industrial valuable thermostable pullulan degrading enzyme from Desulfurococcus mucosus DSM2162. Recombinant protein was purified by a combination of thermal treatment and affinity chromatography, with a yield of 15.94% and 7.69-fold purity. Purified enzyme showed the molecular mass of 55,787 Da with optimum activity at 70 °C and a broad range of pH (5.0-9.0) with kcat of 2150 min^-1 and Km of 6.55 mg.mL^-1, when using starch as substrate. The enzyme activity assay on various polysaccharide substrates revealed the substrate preference of pullulan > amylopectin > β cyclodextrin > starch > glycogen; therefore, it classified as a neopullulanase. The neopullulanase structural analysis by spectrofluorometer, FT-IR, and circular dichroism spectroscopy indicated the corporation of α-helix (47.3%) and β-sheet (31.6%) in its secondary structure. The melting temperature and specific heat capacity calculations using differential scanning calorimetry confirmed its extreme thermal stability. Further, salt-elevated concentrations resulted in oligomeric state dominancy without any significant influence on the starch-degrading ability. The newly cloned archaeal neopullulanase was with broad activity on polysaccharide substrates, with thermal and salt stability. Thus, the Desulfurococcus mucosus DSM2162 neopullulanase can be introduced as a good candidate to be used in carbohydrate industry.

The Modified Hospital Elder Life Program (HELP) in geriatric hospitalized patients in internal wards: A double-blind randomized control trial

Background

Hospital Elder Life Program (HELP) provides protocols based on factors for reducing delirium. Due to the lack of geriatric wards and aged care teams in Iran, it seems that some of the original HELP interventions need to be modified through a trial study. Hence, this study was conducted to determine whether the Iranian modified HELP could reduce delirium in geriatric hospitalized patients.

Methods

This double-blind randomized controlled trial was designed and conducted in a hospital at Kashan University of Medical Sciences in Iran. A total of 195 hospitalized patients aged ≥70 years, were 84 in the Intervention Group (IG) and 111 in the Control Group (CG). After assessing delirium risk factors, participants in the IG group received interventions based on the cognitive, vision/hearing, sleep, mobility, feeding, and hydration protocols by nursing students and the CG group received routine care.

Delirium incidence was assessed by the Confusion Assessment Method. Delirium incidence, cognitive and functional abilities, frailty, fall, and length of stay were outcomes.

Results

The mean age of the patients was 78.53(Standard Deviation = 5.87) years. Delirium incidence was higher in the CG comparing to IG (14.71% vs 3.66%).Significant reduction observed in risk incidence of delirium because of interventions [Odds Ratio:0.124, Confidence Interval: 0.03–0.48].

Conclusion

The modified HELP effectively reduced delirium rates in geriatric hospitalized patients.

Trial registration

This study was registered at the Iranian Registry of Clinical Trials IRCT20180910040995N1.

The emerging role of microRNA in regulating the mTOR signaling pathway in immune and inflammatory responses

The mechanistic/mammalian target of rapamycin (mTOR) is considered to be an atypical protein kinase that plays a critical role in integrating different cellular and environmental inputs in the form of growth factors, nutrients and energy and, subsequently, in regulating different cellular events, including cell metabolism, survival, homeostasis, growth and cellular differentiation. Immunologically, mTOR is a critical regulator of immune function through integrating numerous signals from the immune microenvironment, which coordinates the functions of immune cells and T cell fate decisions. The crucial role of mTOR in immune responses has been lately even more appreciated. MicroRNAs (miRNAs) are endogenous, small, noncoding single-stranded RNAs that act as molecular regulators involved in multiple processes during immune cells development, homeostasis, activation and effector polarization. Several studies have recently indicated that a range of miRNAs are involved in regulating the phosphoinositide 3-kinase/protein kinase B/mTOR (PI3K/AKT/mTOR) signaling pathway by targeting multiple components of this signaling pathway and modulating the expression and function of these targets. Current evidence has revealed the interplay between miRNAs and the mTOR pathway circuits in various immune cell types. The expression of individual miRNA can affect the function of mTOR signaling to determine the cell fate decisions in immune responses through coordinating immune signaling and cell metabolism. Dysregulation of the mTOR pathway/miRNAs crosstalk has been reported in cancers and various immune-related diseases. Thus, expression profiles of dysregulated miRNAs could influence the mTOR pathway, resulting in the promotion of aberrant immunity. This review summarizes the latest information regarding the reciprocal role of the mTOR signaling pathway and miRNAs in orchestrating immune responses.

Osteosarcoma: A comprehensive review of management and treatment strategies

Osteosarcoma, a bone cancer usually seen in children and young adults, is generally a high-grade malignancy presented by extreme metastases to the lungs. Osteosarcoma has a tendency for appearing in bones with rapid growth rate. The etiology of osteosarcoma is multifaceted and poorly understood. A molecular consideration of this disease will lead to a directed tumor treatment. The present treatment for osteosarcoma comprises of an arrangement of systemic chemotherapy and wide surgical resection. Survival rate is increased by the progress of destructive systemic chemotherapies. So, the development of new treatment approaches for metastatic osteosarcoma is essential. Immunomodulation has been used in clinical settings. Through targeting surface antigens expressed on tumor cells, particular antibodies and exploitation of cellular immunotherapy against sarcomas have been confirmed to be effective as cancer therapeutics. In this article, we have reviewed epidemiology, etiology, pathogenesis, diagnosis, and treatment of osteosarcoma and we have focused on different methods of immunotherapy including vaccines, cell-based immunotherapy, cytokines, and monoclonal antibodies.

Phylogeny and species delimitation in Silene sect. Arenosae (Caryophyllaceae): a new section

A putatively monophyletic group of annual Silene species is revised taxonomically and described as the new section S. sect. Arenosae. The species of this section were previously treated as a part of a widely circumscribed and polyphyletic S. sect. Rigidulae. Silene sect. Arenosae as circumscribed here consists of nine species. Members of the section show a predominantly E Mediterranean to SW Asian distribution pattern from Turkey southward to Egypt and eastward to Iran and Pakistan, although most of the species have a limited distribution range. The species of S. sect. Arenosae are characterized by narrowly lanceolate calyx teeth, which are often highly polymorphic, and lanceolate to oblanceolate (non-spathulate) basal leaves. The provided taxonomic revision is based on morphological characters and supported by phylogenetic analyses of two nuclear loci (nrITS and an intron of the RPB2 gene) and one chloroplast locus (the intron of the rps16 gene). The species descriptions are formalized using a novel implementation of the Prometheus Description Model.

Long-term immunogenicity of hepatitis B vaccine and impact of a booster dose on health care

Background: Accidental exposure to sharp instruments is an important problem for health care students. Thus, the aim of this study was to determine the rate of immunity in health care students 2 decades after national neonatal hepatitis B (HB) vaccination.

Methods: All junior students attending medicine, nursing and midwifery schools were screened for anti-HBs. One dose of hepatitis B vaccine was offered to all participants who did not have antibodies to HB surface antigen (anti-HBs) of > 10 IU/L; then, they were tested for anti-HBs after a month. The participants were classified into 3 groups: postboosting nonimmune, postboosting immune, and preboosting immune. Chi square test and ANOVA were used for data analysis.

Results: In the first step, 65.20% of participants did not show immunity, but after receiving a booster dose, only 6.0% remained nonimmune. The mean age of nonimmune students was significantly higher than that of students who had postboosting immune and preboosting immune status (p=0.001 and 0.002, respectively). Also, the mean injection time from last shot was higher in postboosting immune group compared to preboosting immune group (p<0.001). Also, prebooster anti-HBs level was significantly different among participants with suboptimal response and those who developed anamnestic response, indicating preserved immune memory (p=0.001).

Conclusion: High anamnestic response to HBV booster dose indicates sufficient immunity to HBV in the majority of health care students. However, identifying students who cannot respond to a booster dose of vaccine seems to be necessary at the beginning of health care courses.

Assessing the performance of remotely sensed landscape function indices in semi-arid rangelands of Iran

Appropriate rangeland management requires rangeland function analysis at broad scales. This study aimed to examine the potential of remotely sensed function indices extracted from Landsat data to evaluate the function of semi-arid rangelands in central Iran at the sub-basin scale. Three replicate 30-m transects were randomly placed in the dominant slope direction of 14 selected sub-basins. Various structural properties of vegetation (e.g. number and size of vegetation patches and interpatch lengths) and soil surface were scored based on the landscape function analysis (LFA) procedure. The obtained structural and function indices of the LFA, as well as field percent vegetation cover, were compared with the perpendicular distance vegetation index and remotely sensed function indices including proximity, lacunarity, leakiness index, and weighted mean patch size (WMPS). Remotely sensed function indices were found to be capable of discriminating rangeland landscapes with different conditions. Results showed that the structural properties of vegetation considered in the LFA could also be obtained through WMPS and proximity indices (R >0.76; P < 0.01). All indices, except for lacunarity, had significant correlations with percent vegetation cover and the strongest correlation was observed between WMPS and proximity. Our findings highlight the usefulness and efficiency of function indices derived from satellite data in the estimation of structural and functional properties of rangeland landscapes at the sub-basin scale.

Marital satisfaction and adherence to religion

Background: One of the most important determinants of health and marital satisfaction, the family and religious adherence can be effective because religion includes guidelines for life and providing a system of beliefs and values make these features can affect family life. Approach: This descriptive research - an analysis performed to assess the level of satisfaction of 47 questionnaires marital satisfaction questionnaire whose validity and reliability were evaluated and a couple of them asked to assess adherence to religion. The study population included 382 couples in Tehran that a cluster of 22 districts of Tehran were the selected. To analyze the data, ANOVA, Chi-square, and Pearson correlation coefficient using the software SPSS (version 22) became all tests were performed at the 5% level. Results: The data showed that the average age is 34 for women and 38 years for men and the majority of couples are in appropriate level in religiosity (40.5 percent). The results showed a main direct relation among religiosity and marital satisfaction of men and women (p ≤ 0.001). The correlation among religiosity and marital satisfaction of women r = 0.271 and this factor in men r = 0.200 was obtained indicating a direct relationship was significant. Conclusion: couples who were both committed to religion, their marital satisfaction score was more than couples without adherence to religion, and thus promoting religious beliefs and commitment can increase their marital satisfaction in couples.

Clinical response to a second uterine curettage in patients with low-risk gestational trophoblastic disease: a pilot study

OBJECTIVE

To determine the curative effect of a repeat uterine evacuation in patients with low-risk gestational trophoblastic neoplasia.

STUDY DESIGN

Patients with low-risk gestational trophoblastic neoplasia (GTN)(N=12), diagnosed according to the International Federation of Gynecology and Obstetrics 2002 guidelines, were enrolled in a prospective cohort study. Primary outcomes were need for chemotherapy after second uterine evacuation and number of chemotherapy courses needed to achieve complete remission.

RESULTS

Ten patients (83%) did not require chemotherapy and were cured bya second curettage. Two patients failed to respond to the second curettage and received single-agent chemotherapy with actinomycin-D (1.25 mg/m2 biweekly, slow intravenous administration). Both patients responded to chemotherapy as second-line therapy. A 100% remission rate was achieved, with no recurrence at the 1-year follow-up. One patient (8%) had a uterine perforation.

CONCLUSION

Second curettage has a favorable response rate. It seems reasonable to perform a second curettage in patients with low-risk GTN in settings where serum beta-hCG assay follow-up is highly reliable and available. However, its potential complications and inconvenience must be discussed critically with each patient.

Comparison of depression, anxiety, quality of life, vitality and mental health between premenopausal and postmenopausal women

OBJECTIVE

The purpose of this research was to investigate and compare the rates of depression, anxiety, quality of life, vitality and mental health between premenopausal and postmenopausal women.

METHOD

The sample included 218 women selected randomly from the cultural center of Tehran in November and December 2013 and was divided into two groups. The first group included 110 postmenopausal women (45-55 years old). One year had passed since their last monthly period and they had not used any hormones. The second group included 108 premenopausal women (35-45 years old) who had not yet experienced menopause. In order to assess data, three tests were used: the Zung Anxiety Self-Report scale, the Beck Depression Inventory and the Quality of Life questionnaire (SF-36). The gathered data were analyzed with the T-test for independent groups.

RESULTS

The results indicated that all five hypotheses were confirmed. There were significant differences between the scores of anxiety, depression, quality of life, vitality and mental health between the two groups.

CONCLUSION

Since menopausal women spend almost one-third of their long life in this situation, it can be useful to recognize the causes of these disorders in women and their influences on their families. We can also increase their motivation and self-efficacy in order to improve their quality of life.

Effects of Papaver rhoeas (L.) extract on formalin-induced pain and inflammation in mice

Stress amelioration can improve its metabolic as well as other side effects. In the present study, the effects of hydro-alcoholic extract of Papver rhoeas (L.) on formalin-induced pain and inflammation were investigated in male Swiss-Webster mice (20-25 g). Formalin injects in the plantar portion of mice hind paw and pain was studied for 60 min. The plant extract and other drugs were administered intraperitoneally 30 min before formalin. Experiments showed that administration of extract (25, 50 and 100 mg kg(-1)) could induced analgesia in a dose-response manner in both phases of formalin test. More over, the extract inhibits inflammation induced by formalin injection. Naloxone (4 mg kg(-1)), dextromethorphan (20 mg kg(-1)) and NG-nitro-L-arginine-methylester (L-NAME; 10 mg kg(-1)) reduced the extract analgesia in first but not late phase. Extract administration also increased plasma corticosterone level in dose-dependent manner. It could be concluded that Papaver rhoeas (L.) extract could inhibits acute phase of formalin test in mice by opioidergic, glutamatergic and nitricergic mechanisms. In addition, the extract can induce corticosterone plasma level which may be responsible for inhibition of inflammation and chronic phase of pain induced by formalin.

Survey of special needs in elderly people: a qualitative research

The only way for going to rehabilitation and social participation expansion in elderly people is the identification of their special needs in a scientific and accurate way. This study conducted in order to identify the special needs in elderly people.

This article is a part of a qualitative research with grounded theory method. 15 elderly of Tehran city that were selected through a purposeful sampling participated in study. The main method for collecting data was semi-structured interview that continued until theoretical saturation of information. Data was analyzed with Strauss & Corbin coding manner or continued comparison and the assessor’s viewpoints method is used for validity promotion of data. Totally, most important domains of special needs in aging group were: family and relatives, education, movement and transportation, building and places (houses and public places), social participation and occupation, amusement, health and treatment services, and people’s attitude toward their problems.

Those elderly people's special needs that are disabling are often caused by their characteristics and obstacles which are created by society. Therefore, resolving these man-made barriers such as non efficient systems and services, discriminatory policies, prejudice attitudes, etc will help them in the field of rehabilitation and individual independence enhancement.

Survey of special needs in physically disabled people: A qualitative research

After sanction of “the rights of disabled people convention” United Nations Organization have been stressed more on dealing with this group’s needs. Therewith, most of countries in the world have been committed in this field. Therefore with consideration of importance of identifying the needs in disabled people and making policies for them, this study conducted in order to identify the special needs in physically disabled people. This article is a part of a qualitative research with grounded theory method. 15 physically disabled people of Tehran were selected through a purposeful sampling participated in study. The main method for collecting data was semi-structured interview that continued until theoretical saturation of information. Data was analyzed with Strauss & Corbin coding manner or continued comparison and the assessor’s viewpoints method is used for validity promotion of data.

Totally, most important domains of special needs in disabled group were: family and relatives, education, movement and transportation, building and places (houses and public places), social participation and occupation, treatment and rehabilitation services, and people’s attitude toward their problems.

The results indicated that for promoting social participation and function independency in disabled people, should be emphasis on “equality of opportunities” in society rather than “disability”. Thus, public systems and services should be available equally for all, such as physical environments and places, housing, transport system, educational and vocational opportunities, and socio-cultural life like equipments for sport and amusement. Then, physically disabled people can reach to a life with more quality and same with others.

Prevalence and associated factors of persistent diarrhoea in Iranian children admitted to a paediatric hospital

To identify the frequency and associated factors of persistent diarrhoea in a paediatric hospital in Tehran, Islamic Republic of Iran, children admitted with acute diarrhoea were followed prospectively until resolution of the episode. Persistent diarrhoea developed in 19.6% of the 424 diarrhoea cases. Children with persistent diarrhoea were significantly younger than those with acute diarrhoea (15.3 versus 29.4 months). Enteroaggregative Escherichia coli was the most prevalent pathogen in both groups, but otherwise the profile of symptoms and isolated organisms was similar in the 2 groups. History of dietary change prior to admission and use of antibiotics and anticholinergic drugs in the acute phase were significantly higher in the persistent than acute diarrhoea cases.

Does group prenatal care affect satisfaction and prenatal care utilization in Iranian pregnant women?

BACKGROUND

The need to provide high quality prenatal care services, which take account of women's views and specifically address their need for information, support and communication, has been advocated and group prenatal care, had been suggested as one of the ways to achieve this objective. The purpose of this study was to examine the impact of group versus individual prenatal care on satisfaction and prenatal care use.

METHODS

This was a cluster-randomized controlled trial with the health center as the randomization unit that conducted in 2007. Satisfaction was measured through a standardized questionnaire, and the Kotelchuck Adequacy of Prenatal Care Utilization Index was used to measure prenatal care utilization.

RESULTS

We recruited 678 women (group prenatal care, (N= 344) and individual prenatal care, (N=334) in the study. Women in group prenatal care model were more satisfied than women in individual prenatal care model in all areas evaluated, including information, communication, co-ordination and quality of care. Group care women were significantly more likely to have adequate prenatal care than individual care women were (OR=1.35 95% CI=1.26-1.44).

CONCLUSIONS

Group prenatal care was associated with a significant improvement in client satisfaction and prenatal care utilization. This model of care has implications for the planning and provision of prenatal services within public health system, which is moving toward a better quality health care, and increasing use of services.

Socio-economic and medical determinants of low birth weight in Iran: 20 years after establishment of a primary healthcare network

OBJECTIVE

Establishment of a primary healthcare network in Iran has provided free and universal access to primary health care. Although the health status of Iranians has improved since this network was established, the low-birthweight rate has not decreased. The objective of the present study was to describe socio-economic and medical factors related to low birth weight in the context of free and universal access to primary health care.

DESIGN

Descriptive, hospital-based prospective study.

METHODS

Data about socio-economic, reproductive and prenatal condition of 4510 live singleton births from June to October 2004 were gathered using a standard questionnaire by interview and record review. The effect of these conditions on birth weight was investigated using a logistic regression model.

RESULTS

Of 4510 newborns, 305 (6.8%) were low birth weight. Among these low-birthweight newborns, there were 159 preterm and 146 term newborns. Mothers with a primary and secondary education [odds ratio (OR) 6.83, 95% confidence interval (CI) 2.35-7.34 and OR 4.81, 95%CI 1.95-6.37, respectively], who lived with farmer and unskilled worker husbands (OR 2.52, 95%CI 1.12-4.66 and OR 2.91, 95%CI 1.35-2.52, respectively), with a birth interval of 1 year or less (OR 3.54, 95%CI 1.80-5.95) and height less than 155cm (OR 1.82, 95%CI 1.12-3.31) were more likely to have low-birthweight infants.

CONCLUSION

In the context of free and universal access to health care, it is recommended that policy makers should place more emphasis on education as it imparts knowledge and thus influences dietary habits and birth-spacing behaviour. This will lead to a better nutritional status, particularly in dealing with pregnancy, resulting in lower rates of low birth weight.

Densitometric evaluation of skull and jaw bones after administration of thyroid hormones in rats

OBJECTIVES

An investigation was performed by use of optical densitometry to observe the effects of different doses of thyroid hormone on bone density of skull and jaw bones and to evaluate the relationship between T3, T4, thyroid stimulating hormone (TSH) serum levels and bone density.

METHODS

40 Sprague-Dawley rats were randomly divided into four groups with 10 rats in each (a control group that received 10 ml kg(-1) i.p. per day normal saline and three levothyroxine groups that received 5, 10, or 20 microg kg(-1) i.p. per day levothyroxine, respectively). Radiographs were taken of their skulls on days 3 and 16. At the end of the experimental period blood was drawn by intracardiac puncture and serum was analysed for thyroid hormones (T3 and T4) and TSH level. After that, optical density measurements were made on the radiographs of four selected points on the skull and jaw with a digital densitometer. Density measurements were analysed using the student's t-test, one way analysis of variance, Spearman correlation analysis and regression analysis.

RESULTS

Levothyroxine administration reduced bone density (P < or = 0.05) and increasing the dose of thyroid hormone produced a significant decrease of bone density (P < or = 0.05). The mandible was more susceptible to density changes compared with hard palate, skull and alveolar bone (P < or = 0.05).

CONCLUSIONS

Radiographs of the mandible can be utilized to characterize loss of bone density elsewhere. In addition this investigation indicated that optical densitometry is an inexpensive and low risk method for studying bone density.

The effect of thyroid hormone on orthodontic tooth movement in rats

The major goals of this study were to determine the effects of different doses of thyroxin on the rate of orthodontic tooth movement and the force-induced root resorption. In this study fifty male Sprague--Dawley rats were divided into five groups: a normal group with no intervention; a control group in which appliances were placed and 10 ml/kg i.p./day normal saline was injected; and three thyroxin groups in which appliances were placed and 5, 10 and 20/microgram/kg i.p./day L-thyroxin were administered, respectively. A fixed orthodontic appliance consisting of a 5 mm closed-coil spring was ligated between the maxillary incisor and maxillary first molar to deliver an initial force of 60 gm. The results showed that administration of 20/microgram/kg i.p./day L-thyroxin significantly increased the amount of orthodontic tooth movement (p < 0.001). The extent of root resorption as seen from scanning electron micrographs decreased with thyroxin administration.

Differentiation of hepatic cavernous hemangioma from metastases by rare sequence MR imaging

In this study, in order to differentiate cavernous hemangioma and hepatic metastases, rapid acquisition relaxation enhanced (RARE) sequence was used. First, in vivo measurements of T1, T2 relaxation times and proton density were obtained using T1, T2 calculation protocol (TOMIKON S50, 0.5T) and multipoint techniques. These measurements were made from regions of interest placed over the liver, spleen (because of similarity of relaxation time values between hepatic metastases and spleen) and cavernous hemangioma (HCH). Based on these intrinsic parameters, T2 curves signal intensity of three different tissues were constructed. At TE = 500 ms, the signal intensity of the liver and spleen has been near zero whereas in HCH, the signal intensity remained. As RARE sequence is very similar to spin echo (SE), by replacing effective TE(ETE) = 500 ms in the RARE equation, two dimensional contrast-to-noise ratio (CNR) contour plots were constructed demonstrating signal intensity contrast between liver-spleen, liver-Hemangioma for two different scan times (3 min, 7.5 s) and pulse timing. Then, optimal RARE factor and inter echo times were obtained in order to have maximum CNR between liver-Hemangioma and minimum CNR between liver-spleen. These optimal parameters were performed on ten normal and five persons with known HCH. Images showed that in both scan times (3 min, 7.5 s); the liver and spleen were suppressed whereas the HCH was enhanced. The image quality in the scan time of 3 min was better than the scan time of 7.5 s. Moreover, in this study, two different sequences were compared: i) Multi-slice single echo (MSSE) for T1 weighted image ii) RARE (ETE = 80 ms) for T2-weighted image. This comparison was done to show maximum CNR between liver-spleen (metastases) and to choose a better sequence for detecting metastases. CNR in the RARE sequence was more than in the MSSE sequence.

Thermal modeling in cylindrical coordinates using effective conductivity

Predictive thermometry, utilizing minimally invasive sampling techniques, is an essential ingredient in the development of hyperthermia treatment planning capabilities. The authors demonstrate a powerful, but simple approach toward predicting temperature distributions in tissues, based on analytic solution, using in cylindrical symmetry, of the heat diffusion equation. Conduction and localized perfusion effects are combined as an effective conductivity term, readily measurable, and parametrized in a general exponential form. The proposed approach allows a first-order approximation to modeling three typical situations: hypoxic or necrotic tumor core with homogeneously perfused periphery; highly perfused periphery (in rapidly growing tumors); or perfused central cover with a less well-supplied periphery (such as for some invasive tumors). The utility and strength of this approach is that it provides a rapid, accurate model of directly observing the technical quality to be expected for different heating methods, making it possible to optimally configure source distributions in a treatment planning setting.

Heating patterns produced by 434 MHz erbotherm UHF 69

Thermal distributions of 434 MHz Erbotherm H 69 hyperthermia/diathermy generators in tissue-equivalent medium have been investigated. Thermocouples were used to measure temperatures at a set of grid points. Cylindrical and abdominal phantoms were heated and sectioned after heating to measure the temperatures at depth. Results indicate that there is potential for heating deep-seated tumors. The distributions were influenced by the number, shape and geometry of the applicators employed.