Post-COVID-19 Brain [18F] FDG-PET Findings: A Retrospective Single-Center Study in the United States

BACKGROUND AND PURPOSE

The pathophysiology of neurologic manifestations of postacute sequelae of Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) infection is not clearly understood. Our aim was to investigate brain metabolic activity on [18F] FDG-PET/CT scans in patients with a history of coronavirus disease 2019 (COVID-19) infection before imaging.

MATERIALS AND METHODS

This retrospective study included 45 patients who underwent [18F] FDG-PET/CT imaging for any reason and had, at least once, tested positive for COVID-19 at any time before imaging. Fifteen patients had available [18F] FDG-PET scans obtained under identical conditions before the infection. A group of 52 patients with melanoma or multiple myeloma who underwent [18F] FDG-PET/CT were used as controls. Whole-brain 2-sample t test analysis was performed using SPM software to identify clusters of hypo- and hypermetabolism and compare brain metabolic activity between patients with COVID-19 and controls. Paired sample t test comparison was also performed for 15 patients, and correlations between metabolic values of clusters and clinical data were measured.

RESULTS

Compared with the control group, patients with a history of COVID-19 infection exhibited focal areas of hypometabolism in the bilateral frontal, parietal, occipital, and posterior temporal lobes and cerebellum (P = .05 uncorrected at the voxel level, family-wise error-corrected at the cluster level) that peaked during the first 2 months, improved to near-complete recovery around 6 months, and disappeared at 12 months. Hypermetabolism involving the brainstem, cerebellum, limbic structures, frontal cortex, and periventricular white matter was observed only at 2-6 months after infection. Older age, neurologic symptoms, and worse disease severity scores positively correlated with the metabolic changes.

CONCLUSIONS

This study demonstrates a profile of time-dependent brain PET hypo- and hypermetabolism in patients with confirmed SARS-CoV-2 infection.

Demographics, laboratory parameters and outcomes of 1061 patients with coronavirus disease 2019: a report from Tehran, Iran

We aimed to determine the characteristics of coronavirus disease 2019 (COVID-2019) among the Iranian population. In this study, we collected and analysed the demographics, laboratory findings and outcomes of patients with COVID-19 who were admitted to Masih Daneshvari Hospital in Tehran, Iran between 20 February 2020 and 2 April 2020. Among 1061 patients, 692 (65.2%) were male and the median age was 55 years (interquartile range (IQR), 44–66 years). Totally, 129 (12.2%) patients died during hospitalization in the ward or intensive care unit. From the remaining 932 individuals, 46 (5.0%) were admitted to the intensive care unit and 886 (95.0%) were hospitalized in the ward. Those patients who died were significantly older than those hospitalized in the ward (p < 0.001). The median absolute number of lymphocytes was 1.2 × 10³/μL (IQR 0.9 × 10³ to 1.6 × 10³/μL) and 708 (66.7%) patients had lymphopenia (absolute lymphocyte count <1500/μL). Among the laboratory tests, D-dimer, serum ferritin and albumin had the strongest correlations with mortality (r = 0.455, r = 0.412, r = –0.406, respectively; p < 0.001 for each one). In conclusion, laboratory findings could provide useful information with regard to the management of individuals with COVID-19.

Evaluation of the Effects of Acarbose on Weight and Metabolic, Inflammatory, and Cardiovascular Markers in Patients with Obesity and Overweight

Background:

Metabolic syndrome (MetS) refers to a cluster of risk factors for cardiovascular disease and type 2 diabetes. The aim of this study is to assess the effects of acarbose as an antihyperglycemic agent (drug) on late complications of MetS.

Methods:

This double-blind randomized clinical trial was done on patients with MetS admitted to Isfahan Endocrine and Metabolism Research Center. They were assigned randomly to two groups: A who received acarbose (n = 32) and group B who received a placebo (n = 42) for 6 months. Cardiovascular indexes including flow-mediated dilation (FMD), intima-media thickness (IMT), epicardial fat thickness (EFT), and C-reactive protein (CRP) were measured at baseline and 6 months after the treatment and compared between the two groups.

Results:

Post-intervention mean of weight (mean difference: −2.5 ± 0.89) and abdominal obesity (mean difference: −2.2 ± 0.64) in acarbose group were significantly decreased (P value < 0.001). High-density lipoprotein (HDL) level in acarbose group was significantly higher than control group (44.7 ± 7.6 vs 41.1 ± 6.4; P value = 0.043), while the other metabolic parameters were not significantly different between the two groups (P value > 0.05). In both groups, CRP and EFT decreased significantly after the intervention, and the levels of CRP, EFT, and IMT markers in the acarbose group were significantly lower than control group (P value < 0.05).

Conclusions:

The administration of acarbose in patients with MetS can decrease weight and abdominal obesity as well as the reduction of inflammatory and cardiovascular markers, including CRP, EFT, and IMT and also increases HDL.

Oral Magnesium Supplementation Improved Lipid Profile but Increased Insulin Resistance in Patients with Diabetic Nephropathy: a Double-Blind Randomized Controlled Clinical Trial

Low serum magnesium concentrations were associated with development of renal failure. We aimed to determine whether magnesium supplementation improves renal function, insulin resistance, and metabolic profiles in patients with diabetic nephropathy. A total of 80 hypomagnesemic patients diagnosed with type 2 diabetes and early-stage nephropathy were recruited. Subjects received either daily magnesium oxide or placebo for 12 weeks. Biochemical and anthropometric variables were measured. Physical activity and dietary intakes were also recorded. This study was approved by the ethics committee of Isfahan University of Medical Sciences and was registered on the Iranian Registry of Clinical Trials website (IRCT registration no. IRCT201404271485N12). Serum magnesium levels were not changed significantly. Although the supplementation did not influence glycemic indices, patients in the magnesium group had greater insulin resistance compared with the placebo group after intervention (0.3 ± 2.3 μIU/mL vs. - 0.04 ± 2.05, P = 0.04). No significant changes were observed in serum total cholesterol, triglycerides, HDL, LDL, and total cholesterol/HDL cholesterol ratio. Furthermore, magnesium did not affect inflammation, serum levels of creatinine, and blood urine nitrogen. However, a marginal decrease in microalbuminuria (- 3.1 ± 2.2 mg/L vs. - 14 ± 9.9, P = 0.09) was observed. Oral magnesium supplementation slightly improved microalbuminuria but resulted in increased insulin resistance in patients with diabetic nephropathy.

Brain and CSF Volumes in Fetuses and Neonates with Antenatal Diagnosis of Critical Congenital Heart Disease: A Longitudinal MRI Study

BACKGROUND AND PURPOSE

Fetuses and neonates with critical congenital heart disease are at risk of delayed brain development and neurodevelopmental impairments. Our aim was to investigate the association between fetal and neonatal brain volumes and neonatal brain injury in a longitudinally scanned cohort with an antenatal diagnosis of critical congenital heart disease and to relate fetal and neonatal brain volumes to postmenstrual age and type of congenital heart disease.

MATERIALS AND METHODS

This was a prospective, longitudinal study including 61 neonates with critical congenital heart disease undergoing surgery with cardiopulmonary bypass <30 days after birth and MR imaging of the brain; antenatally (33 weeks postmenstrual age), neonatal preoperatively (first week), and postoperatively (7 days postoperatively). Twenty-six had 3 MR imaging scans; 61 had at least 1 fetal and/or neonatal MR imaging scan. Volumes (cubic centimeters) were calculated for total brain volume, unmyelinated white matter, cortical gray matter, cerebellum, extracerebral CSF, and ventricular CSF. MR images were reviewed for ischemic brain injury.

RESULTS

Total fetal brain volume, cortical gray matter, and unmyelinated white matter positively correlated with preoperative neonatal total brain volume, cortical gray matter, and unmyelinated white matter (r = 0.5-0.58); fetal ventricular CSF and extracerebral CSF correlated with neonatal ventricular CSF and extracerebral CSF (r = 0.64 and 0.82). Fetal cortical gray matter, unmyelinated white matter, and the cerebellum were negatively correlated with neonatal ischemic injury (r = -0.46 to -0.41); fetal extracerebral CSF and ventricular CSF were positively correlated with neonatal ischemic injury (r = 0.40 and 0.23). Unmyelinated white matter:total brain volume ratio decreased with increasing postmenstrual age, with a parallel increase of cortical gray matter:total brain volume and cerebellum:total brain volume. Fetal ventricular CSF:intracranial volume and extracerebral CSF:intracranial volume ratios decreased with increasing postmenstrual age; however, neonatal ventricular CSF:intracranial volume and extracerebral CSF:intracranial volume ratios increased with postmenstrual age.

CONCLUSIONS

This study reveals that fetal brain volumes relate to neonatal brain volumes in critical congenital heart disease, with a negative correlation between fetal brain volumes and neonatal ischemic injury. Fetal brain imaging has the potential to provide early neurologic biomarkers.

An interlocked flexible piezoresistive sensor with 3D micropyramidal structures for electronic skin applications

The development of flexible pressure sensors with human-like sensing capabilities is an emerging field due to their wide range of applications from human robot interactions to wearable electronics. Piezoresistive sensors respond to externally induced mechanical stimuli through changes in their electrical resistance. The current state-of-the-art piezoresistive sensors are mainly constructed via dispersion of conductive nanofillers in an elastomer matrix making their performance strongly reliable on the degree of dispersion. Alternatively, changes in the contact area of conductive elastomers result in higher sensitivity and more tunable variables. Herein, an interlocked sensor comprising two flexible layers of 3D pyramidal microstructures is fabricated with a thin layer of carbon nanotubes deposited onto the micropatterns. The introduced array of micropyramids with varying height and pitch sizes allows for higher changes in the contact area upon applying an external load. The results indicate that the height and pitch of the structures together with a newly defined variable, the critical dimension, affect the sensor's sensitivity. An optimal performance is observed for minimized values of the critical dimension. Furthermore, to verify the obtained results, a finite-element-assisted analytical constriction-resistance model is used to capture the piezoresistive response of the sensor. The theoretical results show the high tracking ability of their experimental counterparts.

Predictive Control of the Blood Glucose Level in Type I Diabetic Patient Using Delay Differential Equation Wang Model

Because of increasing risk of diabetes, the measurement along with control of blood sugar has been of great importance in recent decades. In type I diabetes, because of the lack of insulin secretion, the cells cannot absorb glucose leading to low level of glucose. To control blood glucose (BG), the insulin must be injected to the body. This paper proposes a method for BG level regulation in type I diabetes. The control strategy is based on nonlinear model predictive control. The aim of the proposed controller optimized with genetics algorithms is to measure BG level each time and predict it for the next time interval. This merit causes a less amount of control effort, which is the rate of insulin delivered to the patient body. Consequently, this method can decrease the risk of hypoglycemia, a lethal phenomenon in regulating BG level in diabetes caused by a low BG level. Two delay differential equation models, namely Wang model and Enhanced Wang model, are applied as controller model and plant, respectively. The simulation results exhibit an acceptable performance of the proposed controller in meal disturbance rejection and robustness against parameter changes. As a result, if the nutrition of the person decreases instantly, the hypoglycemia will not happen. Furthermore, comparing this method with other works, it was shown that the new method outperforms previous studies.

Evaluation of endothelial function in exogenous subclinical hyperthyroidism and the effect of treatment

Background:

Subclinical hyperthyroidism (SHy) is a widespread condition in which cardiovascular manifestations are frequently occur, but there is still a debate about the vascular responsiveness in it. Measuring flow-mediated dilation (FMD) and intimae-media thickness (IMT) are used to evaluate endothelial function in these patients.

Materials and Methods:

Twenty-five patients with a diagnosis of exogenous SHy and 25 full matched healthy subjects were enrolled. At first FMD of brachial artery and IMT of common carotid artery were obtained from all the participants. In the second phase, in the second phase of study, the dosage of levothyroxine was reduced at least 25% of prior dosage, and this was continued until thyroid stimulating hormone became normal range. Measuring FMD and IMT was repeated after this intervention in the case group.

Results:

The mean age of case and control groups were 38.48 ± 12.05 and 36.72 ± 11.15 years, respectively. The mean of FMD in healthy people was dramatically higher than the subclinical hyperthyroid patients (P < 0.001) but no statistically significant difference was found for IMT (P = 0.459). After intervention in the case group, FMD was meaningfully increased (P < 0.001) but IMT of common carotid artery was not considerably changed (P = 0.491).

Conclusions:

This study demonstrated that FMD decreased in exogenous subclinical hyperthyroid patients which could be partially restored by treatment. These findings suggest that treatment of subclinical hyperthyroid state could improve endothelial dysfunction and at the end decreased the cardiovascular complications.

A constriction resistance model of conjugated polymer based piezoresistive sensors for electronic skin applications

Human intervention can be replaced through the development of tools resulting from utilization of sensing devices possessing a wide range of applications including humanoid robots or remote and minimally invasive surgeries. Similar to the five human senses, sensors interface with their surroundings to stimulate a suitable response or action. The sense of touch which arises in human skin is among the most challenging senses to emulate due to its ultra high sensitivity. This has brought forth novel challenging issues to consider in the field of biomimetic robotics. In this work, using a multiphase reaction, a polypyrrole (PPy) based hydrogel is developed as a resistive type pressure sensor with an intrinsically elastic microstructure stemming from three dimensional hollow spheres. It is shown that the electrical conductivity of the fabricated PPy based piezoresistive sensors is enhanced as a result of adding conductive fillers and therefore, endowing the sensors with a higher sensitivity. A semi-analytical constriction resistance based model accounting for the real contact area between the PPy hydrogel sensors and the electrode along with the dependency of the contact resistance change on the applied load is developed. The model is then solved using a Monte Carlo technique and its corresponding sensitivity is obtained. Comparing the results with their experimental counterparts, the proposed modeling methodology offers a good tracking ability.

Endothelial dysfunction in patients with subclinical hypothyroidism and the effects of treatment with levothyroxine

Background:

Subclinical hypothyroidism (SHT) may increase the risk of cardiovascular disease. We compared endothelial function between SHT patients and euthyroid individuals, and evaluated the effects of levothyroxine therapy on endothelial function in the patients.

Materials and Methods:

In a quasi-experimental study, flow-mediated dilatation (FMD) and intima-media thickness (IMT) were assessed in SHT patients and healthy controls (n = 25 in each group). Patients then received levothyroxine (50 μg/day) for 2 months, and the FMD and IMT assessments were repeated.

Results:

Patients and controls were similar in IMT (0.56 ± 0.09 vs. 0.58 ± 0.08 mm, P = 0.481), but FMD was lower in patients than in controls (4.95 ± 2.02 vs. 6.50 ± 2.57%, P = 0.011). A significant increase was observed in FMD (4.11 ± 2.37%, P = 0.001), but not in IMT (−0.004 ± 0.020 mm, P = 0.327), after levothyroxine therapy among the patients.

Conclusions:

Patients with SHT have endothelial dysfunction which responds to levothyroxine therapy. Randomized placebo-controlled trials are needed to confirm these findings.

Protein-energy Malnutrition in Goitrous Schoolchildren of Isfahan, Iran

BACKGROUND

Some studies have shown the possible role of protein-energy malnutrition (PEM) in persistence of endemic goiter in iodine replenished areas. The present study was conducted to assess the association between PEM and goiter in schoolchildren of Isfahan, Iran.

METHODS

In a cross-sectional study using multistage cluster random-sampling, 2331 schoolchildren with age ranged from 6-13 years old with a female to male ratio of 1.60 were enrolled. Thyroid size was examined by two endocrinologists for goiter detection. Children were considered goitrous if they had palpable or visible goiters according to World Health Organization (WHO)/United Nations children's Fund/International Council for the Control of Iodine Deficiency criteria. Weight and standing height were measured using the standard tools and anthropometric indices were calculated using the WHO AnthroPlus software developed by the World Health Organization. Height-for-age Z-scores (HAZ), weight-for-age Z-scores (WAZ) and body mass index (BMI) for age were calculated for each child. Children with a HAZ, WAZ or BMI-for-age of Z-score < -2.0 were classified as stunted, underweight or thin, respectively. Blood samples were drowned to measure serum thyroid hormones.

RESULTS

Overall, 32.9% of subjects were classified as goitrous. Weight, height, BMI, WAZ and BMI-for-age Z-score were significantly lower in children with goiter than in children who did not have goiter (P < 0.05). The prevalence of goiter in thin children was higher than that in non-thin ones (48.4 vs. 31.6%, odds ratio [OR]: 2.02, 95% confidence interval [CI]: 1.52-2.69, P < 0.001). Although 33.4% of non-stunted children were goitrous, 31% of stunted ones had goiter (P = 0.5). According to the logistic regression model taking sex and age as covariates, the only significant parameter affecting palpable goiter detection was thinness (OR = 2.13, 95% CI: 1.22-3.69, P < 0.001).

CONCLUSIONS

In the present study, we found a high prevalence of goiter in children who were malnourished. It seems that PEM may play a role in the still high prevalence of goiter in this region.

The effect of salsalate on biochemical factors and endothelial dysfunction of prediabetic patients: A randomized clinical trial

BACKGROUND

The beneficial effect of using nonacetylated salicylates such as salsalate on decreasing the speed of diabetes progression is a controversial issue. The aim of this study was to evaluate the effect of salsalate on metabolic-syndrome-associated parameters as well as the endothelial function of diabetic and impaired glucose tolerance patients.

MATERIALS AND METHODS

Patients were collected from Isfahan endocrinology research center referrals. Patients with impaired glucose tolerance diagnosis or newly diagnosed diabetes were enrolled in the study. Patients were randomized to receive 1.5 g salsalate (2 × 750 mg) BID or placebo twice a day for 3 months. After the mentioned period, all patients were recalled and complete examination was done; blood samples for biochemistry measurements were drawn (for measuring FBS, post prandial glucose, HbA1C, Total cholesterol, HDL, TG, LDL) and forearm flow-mediated dilation (FMD) was performed.

RESULTS

Forty patients were enrolled, 32 patients (80%) were female. Mean age of patients was 47.15 ± 6.67 years. FBS (fasting blood sugar) was shown to be significantly different between intervention and control subjects before or after treatment. FMD increased significantly in the intervention group (P = 0.004).

CONCLUSION

The study showed that salsalate decreased FBS levels of patients. It may also improve endothelial function as FMD increased significantly in the intervention group.

Late umbilical cord clamping, neonatal hematocrit and Apgar scores: a randomized controlled trial

OBJECTIVE

Based on current evidence, there is a little agreement on the best timing for after birth umbilical cord clamping. This study was designed to compare the impact of using two different times for cord clamping on hematocrit concentration and Apgar scores of the neonate.

STUDY DESIGN

Fifty-six healthy full-term vaginally born neonates were allocated to early (10 seconds after delivery) and late (3 minutes after delivery) umbilical cord clamping groups in this randomized clinical trial. We recorded the length of the 3rd stage of labor and Apgar score at 5 minutes. Infant's hematocrit was measured at 2 and 18 hours of age.

RESULTS

Neonatal hematocrit differed between the two groups. Late cord clamping group had greater hematocrit at 2 hours (45.5 ± 4 vs. 49.5 ± 4.4, P = 0.0003) and 18 hours (47.7 ± 5.5 vs. 52.9 ± 4.3, P = 0.0002). Apgar scores at 5 minutes (9.3 ± 0.6 vs. 9.4 ± 0.6, p = 0.5) and duration of delivery 3rd stage (10.2 ± 3.7 min vs. 8.9 ± 5 min, P = 0.2) did not differ between early and late cord clamping groups respectively.

CONCLUSION

Late cord clamping leads to a significant increase in the hematocrit of the neonate but it does not have effects on Apgar score and duration of the 3rd stage of labor.

The effect of acupressure on sleep quality in hemodialysis patients

OBJECTIVE

Our purpose was to investigate the effects of acupressure on sleep quality in hemodialysis patients.

DESIGN

Randomized clinical trial.

SETTING

The setting of the study was dialysis wards located in two university hospitals (Imam and Golestan) in Ahvaz, Iran.

INTERVENTIONS

48 end-stage renal disease patients on hemodialysis who scored 5 points or higher on the Pittsburgh Sleep Quality Index (PSQI) were enrolled to the study. Acupressure group received acupressure intervention on the Shenmen (He7) and He Gu (Li4) points in the hands and Sanyingjao (sp6) point in the feet for 4 weeks beside routine care and control group received only routine care.

MAIN OUTCOME MEASURES

subjective sleep quality, latency and duration, habitual sleep efficiency; sleep disturbances, daytime functional status, and use of sleeping medications.

RESULTS

The result indicated significant differences between the acupressure group and the control group after intervention in PSQI global scores (p<0.001) and all sleep quality indices between two groups after intervention: subjective sleep quality (p<0.001), sleep latency (p<0.001), sleep duration (p<0.001), sleep efficiency (p=0.006), sleep disturbance (p<0.001), the use of sleeping medication (p=0.028), and daytime dysfunction (p<0.001).

CONCLUSION

This study supports the effectiveness of acupressure in improving sleep quality of end-stage renal disease patients as a noninvasive therapy.

Thyroid disorders in children and adolescents with type 1 diabetes mellitus in isfahan, iran

OBJECTIVE

Studies in different populations have shown great variation in the prevalence of thyroid diseases in patients with type 1 diabetes mellitus (T1DM). Our aim was to study the prevalence of thyroid disorders such as autoimmunity of thyroid (AIT), thyroid dysfunction, and goiter in children and adolescents with T1DM, compared with age- and sex-matched healthy controls in Isfahan.

METHODS

One hundred patients with T1DM who were referred to Isfahan Endocrine and Metabolism Research Center and 184 healthy schoolchildren matched for age and sex were included. They were examined for goiter by two endocrinologists. Thyroid function test and serum thyroid antibodies (anti-TPO Ab and anti-Tg Ab) were measured.

FINDINGS

The prevalence of subclinical hypothyroidism was high in both groups (18%). T1DM patients had lower frequency of goiter (21% vs. 38%, P=0.001), and higher prevalence of positive AIT (22% vs. 8%, P=0.001), anti-TPO Ab positivity (19.3% vs. 5.3%, P=0.000), and anti-Tg Ab (11.1% vs. 6.4%, P=0.1) in comparison with the control group. Being positive for AIT in diabetic patients meant an odds ratio of 5 (CI 95%: 1.5-15.6) for thyroid dysfunction. There was no association between age, sex, duration of diabetes and HbA(1C) with serum anti-TPO Ab and anti-Tg Ab concentrations in this group.

CONCLUSION

Our results demonstrated the high prevalence of AIT and thyroid dysfunction in patients with T1DM. We suggest regular thyroid function and antibody testing in these patients.

Hyperuricemia after renal transplantation

BACKGROUND

Hyperuricemia is a common complication after kidney transplantation, and may adversely affect graft survival.

OBJECTIVE

To assess the prevalence of and predictors for development of hyperuricemia after renal transplantation.

MATERIALS AND METHODS

Hyperuricemia was defined as a serum uric acid concentration of at least 7.0 mg/dL in men and 6.0 mg/dL in women. From March 2008 to May 2010, uric acid concentration was measured in 12,767 blood samples from 2961 adult renal transplant recipients (64% male and 36% female patients).

RESULTS

Hyperuricemia was observed in 1553 patients (52.4%). The disorder frequently occurred in women (P=.003) and in patients with impaired renal graft function (P=.00). After adjustment for sex, serum creatinine concentration, diabetes mellitus, cyclosporine concentration, and dyslipidemia, only female sex (P=.03) and renal allograft dysfunction (P=.05) were associated with hyperuricemia after kidney transplantation.

CONCLUSION

Hyperuricemia is a common complication after kidney transplantation, and renal allograft insufficiency predisposes to higher uric acid concentration.

Hyperhomocysteinemia after kidney transplantation

OBJECTIVE

To determine the prevalence of hyperhomocysteinemia (plasma homocysteine[Hcy] concentration≥15 μmol/L) and evaluate its correlation with allograft function.

MATERIALS AND METHODS

The study included 159 stable renal transplant recipients (104 men and 55 women). The prevalence and severity of hyperhomocysteinemia were compared in the transplant recipients vs 72 patients (48 men and 24 women) receiving hemodialysis therapy.

RESULTS

The mean (SD; range) fasting total Hcy concentration was higher in the hemodialysis group compared with the renal transplantation group: 27.4 (18.3; 10-95) μmol/L vs 16.6 (9.5; 4.5-45.0) μmol/L (P=.00). Hyperhomocysteinemia occurred more frequently in patients receiving hemodialysis therapy (74% vs 49%). No significant correlation was observed between Hcy concentration and recipient sex, cyclosporine trough concentration and concentration at 2 days after dosing, dyslipidemia,cytomegalovirus infection, diabetes mellitus, or aspartate or alanine aminotransferase concentration. Multivariate regression analysis revealed that serum creatinine concentration (P=.02) was the major determinant of increased total Hcy concentration in renal transplant recipients.

CONCLUSION

A high prevalence of moderate hyperhomocysteinemia was observed in renal transplant recipients. There was no correlation between graft function and Hcy concentration.

The role of thyroid autoantibodies in the etiology of endemic goiter in schoolchildren of Isfahan, Iran

BACKGROUND

Eleven years after the initiation of universal salt iodization program in Iran, the prevalence of goiter is still high in some areas.

AIM

To investigate the role of thyroid autoimmunity in the etiology of residual goiter in schoolchildren of Isfahan, Iran.

MATERIAL AND METHODS

In a cross-sectional study, 2331 schoolchildren were selected by multi-stage random cluster sampling. Thyroid size was estimated in each child by inspection and palpation. Urinary iodine concentration (UIC), serum anti-thyroperoxidase antibody (anti-TPO Ab), and anti-thyroglobulin antibody (Anti-Tg Ab) were measured.

RESULTS

Overall, 32.9% of children had goiter. The median UIC was 1955.5 microg/dl. There was significant difference in prevalence of positive anti-TPO Ab in goitrous (grade 2) and non-goitrous children (9.7 vs 3.7%, p= 0.02). Goitrous children had higher prevalence of positive anti-Tg Ab than non-goitrous ones (15.1 vs 3.1%, p<0.001).

CONCLUSIONS

According to the present study, goiter is still a public health problem in this region. This study suggests that thyroid autoimmunity is among the contributors of goiter persistence after elimination of iodine deficiency in Isfahan.

Evaluation of liposomal and conventional formulations of octyl methoxycinnamate on human percutaneous absorption using the stripping method

The objective of this study was to determine the influence of vehicles on the penetration of octyl methoxycinnamate (OMC), as a UV absorber, to the stratum corneum by the stripping method. The experimental formulations consisted of a conventional o/w emulsion and multilamellar and small unilamellar liposomes (MLVs and SUVs) containing OMC. MLVs containing OMC were prepared by the fusion method and then converted to SUVs by probe sonication. Various formulations were then applied onto the midvolar forearms of six volunteers at a dose of 2 mg/cm2. After determined timepoints, the stripping method was conducted whereby 22 tape strips were applied and subsequently divided into different stripping groups. The sunscreen agent was assessed by HPLC while the SPF (sun protection factor) of the formulations was determined in human volunteers in accordance with the Australian standard. Overall the results indicate that skin accumulation of OMC in MLVs was significantly greater than in the o/w emulsion and SUVs. Furthermore, SUV's penetration into the deeper skin layers was significantly greater than MLV's and that of a conventional o/w emulsion. Also, higher amounts of OMC were recovered from the upper layers of the stratum corneum than from the deeper layers in all the formulations tested. Finally, the SPF of the liposomes containing OMC was slightly greater than that of the control lotions at a similar concentration of OMC. In conclusion, the result of this study indicates that an MLV prepared by the fusion method could be a better vehicle for OMC as a sunscreen since it has a slightly better SPF compared to a conventional formulation and more remains in the stratum corneum, reducing its penetration to the deeper layers.

Is spinal cord isolation a good model of muscle disuse?

The patterns of normal daily activity that are required to maintain normal skeletal muscle properties remain unknown. The present study was designed to determine whether spinal cord isolation can be used as a reliable experimental model of neuromuscular inactivity, that is, as a baseline for the absence of activity. Electromyograms (EMGs) were recorded from selected hindlimb muscles of unanesthetized rats over 24-hour periods before and 7, 30, 60, and 90 days after surgical isolation of the lumbar spinal cord. Our data indicate that some rat slow muscle fibers pre-surgery were activated for less than 3 hours per day. Spinal cord isolation (SI) reduced the mean daily integrated EMG (IEMG) and daily EMG duration in the primary slow extensor muscle (soleus) to <1% of control, and in the primary fast extensor muscles [medial gastrocnemius (MG) and vastus lateralis (VL)] to <2% of control. These parameters were decreased to <8% and 3% of control, respectively, in a primary fast flexor muscle, the tibialis anterior (TA). From 30 to 90 days post-SI, the mean amplitudes of the spontaneous EMG bursts were relatively normal in the soleus, increased approximately 2-fold in the MG and VL, and increased approximately 4-fold in the TA. Some evidence of the normal antagonistic flexor-extensor relationship was apparent in the brief periods of recorded activity post-SI. These results indicate that SI eliminates nearly all of the normal EMG activity in the hindlimb muscles in the presence of relatively normal muscle innervation and functional intraspinal neural circuitry.

Individual voxel-based analysis of gray matter in focal cortical dysplasia

High-resolution MRI of the brain has made it possible to identify focal cortical dysplasia (FCD) in an increasing number of patients. There is evidence for structural abnormalities extending beyond the visually identified FCD lesion. Voxel-based morphometry (VBM) has the potential of detecting both lesions and extra-lesional abnormalities because it performs a whole brain voxel-wise comparison. However, on T1-weighted MRI, FCD lesions are characterized by a wide spectrum of signal hyperintensity that may compromise the results of the segmentation step in VBM. Our purpose was to investigate gray matter (GM) changes in individual FCD patients using voxel-based morphometry (VBM). In addition, we sought to assess the performance of this technique for FCD detection with respect to lesion intensity using an operator designed to emphasize areas of hyperintense T1 signal. We studied 27 patients with known FCD and focal epilepsy and 39 healthy controls. We compared the GM map of each subject (controls and patients) with the average GM map of all controls and obtained a GM z-score map for each individual. The protocol being designed to achieve a maximal specificity, no differences in GM concentration were found in the control group. The z-score maps showed an increase in GM that coincided with the lesion in 21/27 (78%) patients. Five of the six remaining patients whose lesions were not detected by VBM presented with a strong lesion hyperintensity, and a significant part of their lesion was misclassified as white matter. In 16/27 (59%) patients, there were additional areas of GM increase distant from the primary lesion. Areas of GM decrease were found in 8/27 (30%) patients. In conclusion, individual voxel-based analysis was able to detect FCD in a majority of patients. Moreover, FCD was often associated with widespread GM changes extending beyond the visible lesion. In its current form, however, individual VBM may be unable to detect lesions characterized by strong signal intensity abnormalities.

In situ fluidization for peat bed rupture, and preliminary economic analysis

This study concerns in situ fluidization (ISF), a new remediation method with potential application to the remediation of NAPL and heavy metal contaminants, by their release from the fluidized zone generated by a water jet. The present study examines the effect of ISF on layers of peat, of significance owing to its role as an important NAPL and metal contaminant trap. Once trapped, such contaminants are not readily accessible by most remedial methods, due to the low permeability and diffusivity of the peat. A simple tank experiment is used to demonstrate rupture of a peat layer by ISF, with removal of the peat as elutriated fines and segregated peat chunks. The application of ISF in the field is then examined by three field trials in uncontaminated sands, in both saturated and unsaturated conditions. Fluidized depths of up to 1.9 m in the saturated zone (with refusal on a peat layer) and 2.5 m in the unsaturated zone (no refusal) were attained, using a 1.9-m-long, 50 mm diameter jet operated at 5-13 1 s(-1). Pulses of dark turbidity and shell fragments in the effluent indicated the rupture of peat and shelly layers. The experiments demonstrate the hydraulic viability of ISF in the field, and its ability to remove peat-based contaminants. The issues of appropriate jet design and water generation during ISF are discussed, followed by a preliminary economic analysis of ISF relative to existing remediation methods.