Influence of Temporal Variation in Wall Shear Stress on Intima‐Media Thickening in Arteriovenous Fistulae

Arteriovenous fistula (AVF) failure is mainly due to venous stenosis characterized by significant amount of intima‐media thickening (IMT), probably in the presence of negative (inward) remodeling. Our hypothesis is that the longitudinal changes in wall shear stress (WSS) within different configurations of AVF can influence remodeling factors (changes in luminal diameter (ΔD_h) and IMT) during its maturation process. D_h is an equivalent diameter for a noncircular conduit. A total of six AVFs with curved (C‐AVF; n = 3) and straight (S‐AVF; n = 3) configurations were created between the femoral artery and vein of three pigs, bilaterally. CT scans and ultrasounds were utilized to calculate local WSS at 2D (D: days), 7D, and 28D postsurgery. For each AVF, IMT was measured at four regions along the vein using morphometric analyses. At these regions, repeated measurements of WSS and luminal diameter of each AVF were obtained over time. The ΔD_h between 7D and 28D was significantly larger for C‐AVF than for S‐AVF (2.27 ± 0.67 mm vs. 0.02 ± 0.55 mm; p < 0.05). Also, at 28D the amount of IMT in C‐AVF (77.46 ± 7.10 units) was significantly greater (p < 0.05) when compared with S‐AVF (53.71 ± 8.23 units). These structural changes were accompanied by significantly different gradients of WSS over time (τ′) for C‐AVF (?0.56 ± 0.60 dyne/cm²/day) in comparison with S‐AVF (0.71 ± 0.39 dyne/cm²/day). Negative τ′ for C‐AVF corresponded to reduction in WSS level over time resulting in a physiological level of WSS at 28D (4.08 ± 5.08 dyne/cm²). In contrast, a positive τ′ for S‐AVF was associated with the increase in WSS levels over time causing high levels of WSS at 28D (36.68 ± 5.32 dyne/cm²). The decrease in WSS levels for the C‐AVF over time was associated with outward remodeling of the venous wall (favorable to maturation). In contrast, for S‐AVF, the increase in WSS levels over time was associated with inward remodeling and subsequently, venous stenosis. Thus, temporal gradients of WSS, which could be altered by the surgical configuration of AVF, may provide important information on the remodeling behavior of AVFs. Identification of an optimal AVF configuration, which results in a temporal decrease in WSS and an outward remodeling of the venous wall, may reduce AVF maturation failure.     

Preserving Parathyroid Gland Vasculature to Reduce Post-thyroidectomy Hypocalcemia

Background

The failure to preserve parathyroid function in patients who have undergone total thyroidectomy is of major concern, because hypocalcemia is difficult to prevent and remains a common postoperative complication. Here, we describe procedures designed to preserve the vasculature supplying the parathyroid glands and examine both recent outcomes and retrospective reports of results obtained prior to the application of these preservation techniques.

Methods

Our technique for preserving parathyroid function during thyroidectomy was adopted in 2009 and involves separating a relatively long segment of a vessel distally from the thyroid gland. We reviewed the medical records of 1,411 patients who underwent total thyroidectomy, with or without lateral neck dissection, at the Samsung Medical Center from January 2006 through June 2014 to determine outcomes. Patients were divided into three groups according to the time period during which the surgery took place: Group A, 2006–2008 (before the vasculature-preserving technique was applied); Group B, 2009–2011 (the time when the technique was first adopted); and Group C, 2012–2014 (more recent results of the technique). We analyzed the incidence of hypoparathyroidism in the three groups, as well as risk factors that influenced its development.

Results

The rates of transient and permanent hypoparathyroidism in Group A were 25.4 and 4.3 %, respectively. However, the incidence of hypoparathyroidism decreased significantly over time after the vasculature-preserving procedure was adopted. Transient hypoparathyroidism developed in 4.8 % of Group C patients, and only four (0.7 %) of the 565 patients in this group required calcium supplementation, despite the fact that a greater number of patients were included who underwent total thyroidectomy combined with lateral neck dissection. Although female sex and lateral neck dissection tended to increase the rate of transient hypoparathyroidism, multivariate analysis showed that the vasculature-preserving procedure was the only significant risk factor related to postoperative hypoparathyroidism.

Conclusion

The blood flow of the final branch to the parathyroid gland is mostly in the lateral-to-medial direction; therefore, mobilization and preservation of the vessels lateral to the gland is essential to prevent devascularization of the parathyroid gland.

     

Clinically distinguishing between appendicitis and right-sided colonic diverticulitis at initial presentation

PURPOSE: Most patients diagnosed with right-sided colonic diverticulitis complain of right lower quadrant pain, which is frequently confused for appendicitis and therefore may result in unnecessary emergency surgery. In this paper we intend to differentiate between right-sided colonic diverticulitis and appendicitis by initial presentation in the emergency department. MATERIALS AND METHODS: We retrospectively reviewed the medical records of 450 patients between January 1997 and July 2003. Among these patients, 92 with right-sided colonic diverticulitis were classified as group I; 268 patients with simple appendicitis were classified as group II; and 90 patients with perforated appendicitis were classified as group III. RESULTS: Prodromal symptoms were less common in group I (p < 0.05) than in the other groups. In comparing the location of maximal tenderness among groups, 19.6% of group I patients complained of maximal tenderness at a point lateral to McBurney's point, a greater percentage than those in groups II and III (p=0.002). Group I experienced less leukocytosis (10,913.8/mm(3)) than did groups II (13,238.3/mm(3)) and III (15,589.3/mm(3)). The percentage of segmented forms in the differential counts was also smaller in group I (73.6%) than in groups II (79.1%) and III (81.8%). In addition, the proportion of lymphocytes was larger in group I (17.7%) than in groups II (13.9%) and III (9.3%). CONCLUSION: Among patients complaining of right lower quadrant pain in an emergency setting, right-sided colonic diverticulitis must be considered in the following conditions to avoid unnecessary emergency operations: lack of prodromal symptoms, tenderness at a point lateral to McBurney's point, and absent or mild leukocytosis with a low fraction of segmented forms and a high fraction of lymphocytes in the CBC.     

Health service utilization,unmet healthcare needs,and the potential of telemedicine services among Korean expatriates

Background

With the significant growth of migration and expatriation, facilitated by increased global mobility, the number of Koreans living abroad as of 2016 is approximately 7.4 million (15% of the Korean population). Healthcare utilization or health problems, especially among expatriates in developing countries, have not been well researched despite the various health risks these individuals are exposed to. Consequently, we identified the health utilization patterns and healthcare needs among Korean expatriates in Vietnam, Cambodia, and Uzbekistan.

Methods

This cross-sectional survey examined 429 Korean expatriates living in Vietnam (n?=?208), Cambodia (n?=?60), and Uzbekistan (n?=?161) who had access to the Internet and were living abroad for at least 6?months. A 67-item questionnaire was used, and feedback was received via an online survey program. Stepwise logistic regression analyses were performed to evaluate factors associated with unmet healthcare needs and preferences of certain type of telemedicine.

Results

We found that 45.5% (195/429) of respondents had used medical services in their country of stay. Among those who visited health institutions >?3 times, the most popular choice was general hospitals (39.4%, 15/38); however, they initially visited Korean doctors’ or local doctors’ offices. The most essential criteria for healthcare service facilities was a “skilled professional” (39.3%, 169/429), 42% wanted a health program for chronic disease management, and 30% wanted specialized internal medicine. A substantial number wanted to access telemedicine services and were willing to pay for this service. They were particularly interested in experts’ second opinion (61.5%, 264/429) and quick, 24-h medical consultations (60.8%, 261/429). Having unmet healthcare needs and being younger was strongly associated with all types of telemedicine networks.

Conclusions

Nearly half of the expatriates in developing countries had unmet healthcare needs. Telemedicine is one potential solution to meet these needs, especially in developing countries.

     

Spontaneous regression of congenital corneal opacity

Graefe's Archive for Clinical and Experimental Ophthalmology - To determine the incidence of spontaneous regression of congenital corneal opacity (CCO) and identify clinical factors associated...     

External validation of the post-varicocele repair semen analysis nomogram to predict total motile sperm count: A multicenter study

Total motile sperm count is an important parameter for predicting the probability of natural pregnancy. We have externally validated the Samplaski's post-varicocele repair semen analysis nomogram to confirm the predictive accuracy of total motile sperm count. A total of 300 patients who had undergone varicocelectomy between July 2016 and July 2019 from 4 treatment centres were included in this validation cohort study. The predictive performance of the externally validated nomogram was revealed by applying the Pearson correlation coefficient (R = 0.328; 95% confidence interval (CI) 0.220–0.435; p < .001). Compared to Samplaski's nomogram result (R = 0.581; 95% CI 0.186–0.729), our study also revealed a statistically significant rate. However, it had a relatively lower correlation coefficient rate. Notably, the predicted total motile sperm count was lower than the observed post-varicocelectomy total motile sperm count. The calibration plot revealed that the discrepancy between the predicted and observed total motile sperm count was plausible. However, it had low explanatory power in this nomogram model. This validation study demonstrates that the post-varicocele repair Samplaski's nomogram predicts a relatively lower total motile sperm count than the observed count.     

Transabdominal near infrared oximetry of hypoxic stress in fetal sheep brain in utero

The feasibility of transabdominal near-infrared (NIR) spectroscopy for detecting and quantifying fetal hypoxia in utero is demonstrated in a pregnant ewe model. A frequency domain NIR spectroscopy probe, consisting of two detectors and six sources operating at three wavelengths (675, 786, and 830 nm), was placed on the maternal abdomen directly above the fetal head. Fetal hypoxia was indirectly induced through occlusion of uterine blood flow for approximately 3 min. NIR photon diffusion measurements were made during a baseline period, during hypoxia of the fetus, and during recovery. Fetal blood samples were drawn from the fetal brachial artery and jugular veins at several time points during the cycle. Seven hypoxic cycles were induced in a total of five pregnant ewes. The NIR measurements were analyzed by using a two-layer diffusion model to deconvolve the fetal blood saturation from that of the pregnant ewe. Fetal hypoxia was detected. Good agreement was found between fetal blood saturation determined by the transabdominal NIR method and arterial and venous fetal blood saturation quantified from fetal blood samples by using a hemoximeter.     

Acute Lower Respiratory Tract Infections in Soldiers,South Korea,April 2011–March 2012

During April 2011–March 2012, we retrospectively reviewed medical records for South Korea soldiers to assess the etiology and epidemiology of acute viral lower respiratory tract infections. Adenovirus was the most commonly identified virus (63.2%) and the most common cause of pneumonia (79.3%) and hospitalization (76.6%); 3 soldiers died of adenovirus-related illness.     

A new Centiloid method for 18F-florbetaben and 18F-flutemetamol PET without conversion to PiB

European Journal of Nuclear Medicine and Molecular Imaging - We developed a new method to directly calculate Centiloid (CL) units of 18F-florbetaben (FBB) and 18F-flutemetamol (FMM) without...