Pain perception: is there a role for primary somatosensory cortex?

Anatomical, physiological, and lesion data implicate multiple cortical regions in the complex experience of pain. These regions include primary and secondary somatosensory cortices, anterior cingulate cortex, insular cortex, and regions of the frontal cortex. Nevertheless, the role of different cortical areas in pain processing is controversial, particularly that of primary somatosensory cortex (S1). Human brain-imaging studies do not consistently reveal pain-related activation of S1, and older studies of cortical lesions and cortical stimulation in humans did not uncover a clear role of S1 in the pain experience. Whereas studies from a number of laboratories show that S1 is activated during the presentation of noxious stimuli as well as in association with some pathological pain states, others do not report such activation. Several factors may contribute to the different results among studies. First, we have evidence demonstrating that S1 activation is highly modulated by cognitive factors that alter pain perception, including attention and previous experience. Second, the precise somatotopic organization of S1 may lead to small focal activations, which are degraded by sulcal anatomical variability when averaging data across subjects. Third, the probable mixed excitatory and inhibitory effects of nociceptive input to S1 could be disparately represented in different experimental paradigms. Finally, statistical considerations are important in interpreting negative findings in S1. We conclude that, when these factors are taken into account, the bulk of the evidence now strongly supports a prominent and highly modulated role for S1 cortex in the sensory aspects of pain, including localization and discrimination of pain intensity.

Cortical activation by tactile and painful stimuli in hemispherectomized patients

Hemispherectomized patients are able to perceive tactile and painful stimuli on their nonparetic as well as paretic body halves. We have used functional MRI to study the cortical mechanisms underlying this preserved somatosensory capacity. Nonpainful brushing and painful heat were applied to the skin of the legs in four hemispherectomized patients and, for comparison, in four normal subjects. Cortical activation was studied with a 1.5 T scanner using a BOLD (blood oxygen level dependent) protocol. All patients rated both the brushing and the heat pain as almost equally intense on each leg and the ratings were similar to those in normals. Brushing on the nonparetic leg activated primary and secondary somatosensory cortices (S1 and S2) in all patients, similar to findings in normals. Brushing on the paretic leg activated S1 in two patients and S2 in one of these patients. Heat pain activated S2, insular cortex and anterior cingulate cortex to a similar degree for both legs, but the activation was weaker in the patients than in the normals. For the individual patient, there was generally no obvious correlation between cortical activation as studied with the BOLD technique and psychophysical performance. The findings from tactile stimulation of the nonparetic leg, that the activation was similar to the contralateral activation in normals, suggest that tactile information processing in the hemisphere contralateral to the stimulation is independent of the corpus callosum. In contrast, the pain activation for the nonparetic leg was weaker than in normals, suggesting that pain activation in the hemisphere contralateral to the stimulation is dependent on transcallosal information processing. The latter finding was corroborated by a subnormal capacity for pain localization on the nonparetic foot in two of the patients. The findings from stimulation of the paretic leg show that areas typically involved in the processing of tactile and painful stimuli can be activated by ipsilateral pathways directly from the periphery. The tactile-evoked ipsilateral S1 activation may be due to subcortical reorganization, since it was not observed in the normal subjects.

The importance of accurate repair of the orbicularis oris muscle in the correction of unilateral cleft lip

Most of the attempts and efforts in cleft lip repair have been directed toward the skin incision. The importance of the orbicularis oris muscle repair has been emphasized in recent years. The well-designed skin incision with simple repair of the orbicularis oris muscle has produced a considerable improvement in the appearance of the upper lip; however, the repaired upper lip seems to change its shape abnormally in motion and has a tendency to be distorted with age if the orbicularis oris muscle is not repaired precisely and accurately. Following the dissection of the normal upper lip and unilateral cleft lip in cadavers, we could find two different components in the orbicularis oris muscle, a superficial and a deep component. One is a retractor and the other is a constrictor of the lip. They have antagonistic actions to each other during lip movement. We also can identify these two different components of the muscle in the cleft lip patient during operation. We thought inaccurate and mixed connection between these two different functional components could make the repaired lip distorted and unbalanced, which would get worse during growth. By identification and separate repair of the two different muscular components of the orbicularis oris muscle (i.e., repair of the superficial and deep components on the lateral side with the corresponding components on the medial side), better results in the dynamic and three-dimensional configuration of the upper lip can be achieved, and unfavorable distortion can be avoided as the patients grow.(ABSTRACT TRUNCATED AT 250 WORDS)

Subtypes of major depression: latent class analysis in depressed Han Chinese women

BACKGROUND

Despite substantial research, uncertainty remains about the clinical and etiological heterogeneity of major depression (MD). Can meaningful and valid subtypes be identified and would they be stable cross-culturally?

METHOD

Symptoms at their lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾ 30 years, with recurrent DSM-IV MD. Latent class analysis (LCA) was performed in Mplus. RESULTS; Using the nine DSM-IV MD symptomatic A criteria, the 14 disaggregated DSM-IV criteria and all independently assessed depressive symptoms (n = 27), the best LCA model identified respectively three, four and six classes. A severe and non-suicidal class was seen in all solutions, as was a mild/moderate subtype. An atypical class emerged once bidirectional neurovegetative symptoms were included. The non-suicidal class demonstrated low levels of worthlessness/guilt and hopelessness. Patterns of co-morbidity, family history, personality, environmental precipitants, recurrence and body mass index (BMI) differed meaningfully across subtypes, with the atypical class standing out as particularly distinct.

CONCLUSIONS

MD is a clinically complex syndrome with several detectable subtypes with distinct clinical and demographic correlates. Three subtypes were most consistently identified in our analyses: severe, atypical and non-suicidal. Severe and atypical MD have been identified in multiple prior studies in samples of European ethnicity. Our non-suicidal subtype, with low levels of guilt and hopelessness, may represent a pathoplastic variant reflecting Chinese cultural influences.

The structure of the symptoms of major depression: exploratory and confirmatory factor analysis in depressed Han Chinese women

BACKGROUND

The symptoms of major depression (MD) are clinically diverse. Do they form coherent factors that might clarify the underlying nature of this important psychiatric syndrome?

METHOD

Symptoms at lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾30 years with recurrent DSM-IV MD. Exploratory factor analysis (EFA) and confirmatoryfactor analysis (CFA) were performed in Mplus in random split-half samples.

RESULTS

The preliminary EFA results were consistently supported by the findings from CFA. Analyses of the nine DSM-IV MD symptomatic A criteria revealed two factors loading on: (i) general depressive symptoms; and (ii) guilt/suicidal ideation. Examining 14 disaggregated DSM-IV criteria revealed three factors reflecting: (i) weight/appetite disturbance; (ii) general depressive symptoms; and (iii) sleep disturbance. Using all symptoms (n = 27), we identified five factors that reflected: (i) weight/appetite symptoms; (ii) general retarded depressive symptoms; (iii) atypical vegetative symptoms; (iv) suicidality/hopelessness; and (v) symptoms of agitation and anxiety.

CONCLUSIONS

MD is a clinically complex syndrome with several underlying correlated symptom dimensions. In addition to a general depressive symptom factor, a complete picture must include factors reflecting typical/atypical vegetative symptoms, cognitive symptoms (hopelessness/suicidal ideation), and an agitated symptom factor characterized by anxiety, guilt, helplessness and irritability. Prior cross-cultural studies, factor analyses of MD in Western populations and empirical findings in this sample showing risk factor profiles similar to those seen in Western populations suggest that our results are likely to be broadly representative of the human depressive syndrome.

Hemodynamics of the Fontan connection: an in-vitro study

The Fontan operation is one in which the right heart is bypassed leaving the left ventricle to drive the blood through both the capillaries and the lungs, making it important to design an operation which is hemodynamically efficient. The object here was to relate the pressure in Fontan connections to its geometry with the aim of increasing the hemodynamically efficiency. From CT or magnetic resonance images, glass models were made of realistic atrio-pulmonary (AP) and cavo-pulmonary (CP) connections in which the right atrium and/or ventricle are bypassed. The glass models were connected to a steady flow loop and flow visualization, pressure and 3 component LDA measurements made. In the AP model the large atrium and curvature of the conduit created swirling patterns, the magnitude of which was similar to the axial velocity. This led to an inefficient flow and a subsequent large pressure loss (780 Pa). In contrast, the CP connection with a small intra-atrial chamber had reduced swirling and a significantly smaller pressure loss (400 Pa at 8 l.min) and was therefore a more efficient connection. There were, however, still pressure losses and it was found that these occurred where there was a large bending of the flow, such as from the superior vena cava to the MPA and from the MPA to the right pulmonary artery.

Prevalence of common skin diseases and their associated factors among military personnel in Korea: a cross-sectional study

This study was conducted to clarify the prevalence of common skin diseases and their associated factors among military personnel in Korea. Four dermatologists visited adjacent military units and examined soldiers. A structured questionnaire that included questions about known skin diseases, demographic information, and questions for the Perceived Stress Index was completed for each participant. The soldiers that had been diagnosed with a skin disease answered one additional questionnaire (Skindex-29) which assess the influence of an individual's skin disease on daily life. Of 1,321 soldiers examined, 798 (60.4%) had one or more skin diseases. The three most common skin problems were acne (35.6%), tinea pedis (15.2%) and atopic dermatitis (5.1%). The diseases closely related to the period of military service were acne, tinea pedis, viral warts and corns. The diseases related to the amount of stress were atopic dermatitis, seborrheic dermatitis, and acne. The most troublesome skin diseases were atopic dermatitis, tinea cruris, and seborrheic dermatitis. These results demonstrated that the prevalence of skin disease among military personnel in Korea is very high, and that some of the skin disorders may have a significant influence on their daily lives.

An Easy-to-Use Machine Learning Model to Predict the Prognosis of Patients With COVID-19: Retrospective Cohort Study

Background

Prioritizing patients in need of intensive care is necessary to reduce the mortality rate during the COVID-19 pandemic. Although several scoring methods have been introduced, many require laboratory or radiographic findings that are not always easily available.

Objective

The purpose of this study was to develop a machine learning model that predicts the need for intensive care for patients with COVID-19 using easily obtainable characteristics—baseline demographics, comorbidities, and symptoms.

Methods

A retrospective study was performed using a nationwide cohort in South Korea. Patients admitted to 100 hospitals from January 25, 2020, to June 3, 2020, were included. Patient information was collected retrospectively by the attending physicians in each hospital and uploaded to an online case report form. Variables that could be easily provided were extracted. The variables were age, sex, smoking history, body temperature, comorbidities, activities of daily living, and symptoms. The primary outcome was the need for intensive care, defined as admission to the intensive care unit, use of extracorporeal life support, mechanical ventilation, vasopressors, or death within 30 days of hospitalization. Patients admitted until March 20, 2020, were included in the derivation group to develop prediction models using an automated machine learning technique. The models were externally validated in patients admitted after March 21, 2020. The machine learning model with the best discrimination performance was selected and compared against the CURB-65 (confusion, urea, respiratory rate, blood pressure, and 65 years of age or older) score using the area under the receiver operating characteristic curve (AUC).

Results

A total of 4787 patients were included in the analysis, of which 3294 were assigned to the derivation group and 1493 to the validation group. Among the 4787 patients, 460 (9.6%) patients needed intensive care. Of the 55 machine learning models developed, the XGBoost model revealed the highest discrimination performance. The AUC of the XGBoost model was 0.897 (95% CI 0.877-0.917) for the derivation group and 0.885 (95% CI 0.855-0.915) for the validation group. Both the AUCs were superior to those of CURB-65, which were 0.836 (95% CI 0.825-0.847) and 0.843 (95% CI 0.829-0.857), respectively.

Conclusions

We developed a machine learning model comprising simple patient-provided characteristics, which can efficiently predict the need for intensive care among patients with COVID-19.

Long-term exposure to air pollution and the blood lipid levels of healthy young men

BACKGROUND

There is insufficient evidence of an association between long-term exposure to air pollution and changes in blood lipid levels, and assessments may be influenced by residual confounding factors, such as socioeconomic status.

OBJECTIVES

To investigate the associations between long-term exposure to air pollution and blood lipid profiles while controlling for the risk of residual confounding factors.

METHODS

We conducted a study involving conscripted Korean soldiers to assess the associations between air pollution and blood lipid levels. The soldiers, who were randomly distributed among military units throughout the country, led homogenous lives and were subjected to health checkups 8-12 months post-enlistment. We analyzed data pertaining to those who enlisted and underwent health checkups in 2019 (n = 12,778) using linear mixed models. Additionally, we evaluated quantile-specific associations using quantile regression models. We also assessed interactions based on body mass index (BMI) at the time of enlistment (≥25.0 vs. < 25.0 kg/m²).

RESULTS

The linear mixed models revealed that a 10-µg/m³ increase in fine particulate matter ≤ 2.5 μm (PM_2.5) decreased high-density lipoprotein cholesterol (HDL-C) levels by -0.66% (95% confidence interval [CI]: -1.21, -0.10), and a 10-ppb increase in nitrogen dioxide (NO₂) increased total cholesterol (TC) levels by 1.04% (95% CI: 0.24, 1.84). In the quantile regression models, associations were also found at specific deciles. PM_2.5 exposure contributed to higher TC, NO₂ resulted in higher triglycerides and lower HDL-C, and ozone (O₃) led to lower HDL-C. The association between O₃ and TC differed according to BMI (p-value for interaction = 0.03); among those with a BMI ≥ 25.0 kg/m², a 10-ppb increase in O₃ increased TC by 1.09% (95% CI: 0.20, 1.09).

DISCUSSION

These results shed new light on the importance of controlling air pollution, which can contribute to abnormal blood lipid levels, an independent risk factor for cardiovascular disease.

Prediction of patients requiring intensive care for COVID-19: development and validation of an integer-based score using data from Centers for Disease Control and Prevention of South Korea

BACKGROUND

Unavailability or saturation of the intensive care unit may be associated with the fatality of COVID-19. Prioritizing the patients for hospitalization and intensive care may be critical for reducing the fatality of COVID-19. This study aimed to develop and validate a new integer-based scoring system for predicting patients with COVID-19 requiring intensive care, using only the predictors available upon triage.

METHODS

This is a retrospective study using cohort data from the Korean Centers for Disease Control and Prevention that included all admitted patients with COVID-19 between January 19 and June 3, 2020, in South Korea. The primary outcome was patients requiring intensive care defined as actual admission to the intensive care unit; at any time use of an extracorporeal life support device, mechanical ventilation, or vasopressors; and death. Patients admitted until March 20 were included for the training dataset to develop the prediction models and externally validated for the patients admitted afterward. Two logistic regression models were developed with different predictors and the predictive performance was compared: one with patient-provided variables and the other with added radiologic and laboratory variables. An integer-based scoring system was developed based on the developed logistic regression model.

RESULTS

A total of 5193 patients were considered, with 4663 patients included after excluding patients with age under 18 or insufficient data. For the training dataset, 3238 patients were included. Of the included patients, 444 (9.5%) patients required intensive care. The model developed with only the clinical variables showed an area under the curve of 0.884 for the validation set. The performance did not differ when radiologic and laboratory variables were added. Seven variables were selected for developing an integer-based scoring system: age, sex, initial body temperature, dyspnea, hemoptysis, history of chronic kidney disease, and activities of daily living. The area under the curve of the scoring system was 0.880.

CONCLUSIONS

An integer-based scoring system was developed for predicting patients with COVID-19 requiring intensive care, with high performance. This system may aid decision support for prioritizing the patient for hospitalization and intensive care, particularly in a situation with limited medical resources.

Pulmonary blood velocity profile variability in open-chest dogs: influence of acutely altered hemodynamic states on profiles, and influence of profiles on the accuracy of techniques for cardiac output determination

Clinical investigations focused on finding characteristics of noninvasively obtained measurements of pulmonary blood velocity that can be used to quantitate pulmonary blood flow and/or pulmonary pressure have often yielded results whose imprecision has been attributed to flow pattern variability. To determine flow pattern variability in an in vivo animal model in varying hemodynamic states, main pulmonary artery blood velocity waveforms were recorded in 17 dogs at 2-mm intervals along an anterior to posterior wall-oriented axis using a 20-MHz pulsed Doppler needle probe. Control data were obtained before the animals were subjected to altered flow (atrial level shunts) and pressure (10% O2 inhalation) states. Instantaneous velocity profiles were computed throughout the cardiac cycle. Estimates of pulmonary blood flow were obtained assuming an elliptical model of the pulmonary artery which allowed computation of velocity at all points in the cross section, based on the measured values along the axis. Model-based estimates were compared to measured values and estimates obtained in the traditional fashion, i.e., the product of centerline velocity and cross-sectional area. Results clearly showed marked interanimal variability, even in control states. Reverse flow in the posterior half of the vessel, which tended to become more pronounced with increased pulmonary artery pressure, was observed during late systole and early diastole. Elevated pulmonary blood flow tended to increase the maximum velocities along the anterior wall relative to midline velocities. Neither estimate of cardiac output yielded consistently accurate results (r = 0.77 for model-based method, r = 0.80 for area times central velocity method). Findings of this study, which highlight the dependency of waveform characteristics on sampling site, the large degree of intersubject variability, and the need for large or multiple sample volumes for pulmonary blood flow determination, help clarify inconsistencies observed by clinicians and suggest that future work with animal models will facilitate a greater understanding of the determinants of human pulmonary velocity waveforms.

Effects of chronically elevated pulmonary arterial pressure and flow on right ventricular afterload

The effects of pulsatile hemodynamics on right ventricle-pulmonary circulation interactions were studied in control lambs and in two lamb models of altered pulmonary hemodynamics induced at infancy: elevated pulmonary arterial pressure (PAP) was created by the infusion of monocrotaline pyrrole (MCTP), and elevated pulmonary arterial blood flow was obtained by the creation of an arteriovenous fistula (Shunt). High-fidelity PAP, midvessel Doppler blood velocity (PAV), and cardiac output (CO) were measured in open-chest, anesthetized lambs. PAV waveforms were normalized to match the measured CO. Measured pressure and flow signals were separated in the time domain into forward and backward components. Pulmonary input impedance and indexes quantifying the timing of the reflected wave pulse (beginning of reflected pulse, duration of reflected pulse in systole, and duration of reflected wave in diastole) were calculated for each group. Results indicate that in control animals the reflected wave returned late in systole and extended through much of diastole, thereby increasing diastolic pressure like a counterpulsation balloon. No significant differences in the timing indexes were found between Shunt and control animals. In the MCTP group, the reflected wave returned significantly earlier than normal with the peak reflected pulse occurring before valve closure. The resulting augmentation of systolic pressure and, therefore, large pulse pressure is consistent with pressure waveforms observed in clinical pulmonary hypertension. We conclude that early wave reflection exerts a detrimental effect in pulmonary hypertension by unfavorably loading the still-ejecting right ventricle.

The acute effects of pneumonectomy on pulmonary vascular impedance in the dog

Pulmonary vascular impedance is a measure of the pulsatile characteristic of pressure and flow that occurs in the proximal pulmonary arteries. Pulmonary vascular resistance (PVR) is most influenced by the distal circulation of the lung. This study was performed to evaluate the changes that occurred in pulmonary vascular impedance, as well as in other hemodynamic variables, following pneumonectomy by a closed-chest method in 10 anesthetized dogs. The following observations were made (numbers compare mean values for the 10 dogs before and after pneumonectomy): (1) PVR increased from 447 to 761 dyne sec cm-5 (p = .02); (2) the oscillatory work of the right ventricle increased from 1.23 to 1.76 J/min (p = .006); (3) the mean pulmonary artery pressure increased from 14 to 18.8 mm Hg (p = .0001); and (4) cardiac output and heart rate remained unchanged. Surprisingly, the estimated characteristic impedance (the impedance to oscillatory flow in the proximal bed) did not change significantly (279 to 296 dyne sec cm-5). This observation cannot be explained by the usual lumped compartmental models classically used to characterize the pulmonary vascular bed.

Three-dimensional visualization of pulmonary blood flow velocity profiles in lambs

For a better understanding of the characteristics of blood flow in the pulmonary artery, we constructed three-dimensional images of velocity profiles of blood flow in the pulmonary artery from pulsed Doppler ultrasound recordings in 14 lambs aged 28-40 days. In 8 lambs, pulmonary hypertension was created by the central venous injection of monocrotaline pyrrole. Six lambs served as unaltered controls. The velocity data were sampled in 2 mm increments along both an anterior-posterior axis and a right-left orthogonal axis in the main pulmonary artery. Using a computer-generated cross-sectional velocity matrix consisting of 0.25 mm square grids, the velocity of blood flow was estimated at each intersection. The cross-sectional velocity matrices were generated at 5 msec intervals during the entire cardiac cycle. In all animals, significant velocity reversal was detected near the posterior wall. In 7 of 14 animals, the peak forward velocity was located near the posterior wall. Three of 8 hypertensive models showed reacceleration during the mid-systolic phase at the center of the velocity waveform, but one reacceleration disappeared at a point only 2 mm away from the center of the vessel toward the posterior wall. Acceleration time correlated well with the mean pulmonary arterial pressure (PAP) (r = -0.85) and the log10 PAP (r = -0.86). Corrected acceleration time (acceleration time divided by the square root of the cardiac cycle length) also correlated with PAP (r = -0.78) and the log10 PAP (r = -0.81).

COVID-19 Outcome Prediction and Monitoring Solution for Military Hospitals in South Korea: Development and Evaluation of an Application

BACKGROUND

COVID-19 has officially been declared as a pandemic, and the spread of the virus is placing sustained demands on public health systems. There are speculations that the COVID-19 mortality differences between regions are due to the disparities in the availability of medical resources. Therefore, the selection of patients for diagnosis and treatment is essential in this situation. Military personnel are especially at risk for infectious diseases; thus, patient selection with an evidence-based prognostic model is critical for them.

OBJECTIVE

This study aims to assess the usability of a novel platform used in the military hospitals in Korea to gather data and deploy patient selection solutions for COVID-19.

METHODS

The platform's structure was developed to provide users with prediction results and to use the data to enhance the prediction models. Two applications were developed: a patient's application and a physician's application. The primary outcome was requiring an oxygen supplement. The outcome prediction model was developed with patients from four centers. A Cox proportional hazards model was developed. The outcome of the model for the patient's application was the length of time from the date of hospitalization to the date of the first oxygen supplement use. The demographic characteristics, past history, patient symptoms, social history, and body temperature were considered as risk factors. A usability study with the Post-Study System Usability Questionnaire (PSSUQ) was conducted on the physician's application on 50 physicians.

RESULTS

The patient's application and physician's application were deployed on the web for wider availability. A total of 246 patients from four centers were used to develop the outcome prediction model. A small percentage (n=18, 7.32%) of the patients needed professional care. The variables included in the developed prediction model were age; body temperature; predisease physical status; history of cardiovascular disease; hypertension; visit to a region with an outbreak; and symptoms of chills, feverishness, dyspnea, and lethargy. The overall C statistic was 0.963 (95% CI 0.936-0.99), and the time-dependent area under the receiver operating characteristic curve ranged from 0.976 at day 3 to 0.979 at day 9. The usability of the physician's application was good, with an overall average of the responses to the PSSUQ being 2.2 (SD 1.1).

CONCLUSIONS

The platform introduced in this study enables evidence-based patient selection in an effortless and timely manner, which is critical in the military. With a well-designed user experience and an accurate prediction model, this platform may help save lives and contain the spread of the novel virus, COVID-19.

The short head of the biceps femoris as a monitor for the free lateral thigh flap in pharyngoesophageal reconstruction

Free flaps are frequently used to reconstruct the defect following radical resection of pharyngoesophageal malignancy but postoperative monitoring of buried flaps is difficult. We have designed a monitoring-muscle flap using the short head of the biceps femoris muscle when using a free lateral thigh flap. The third and fourth perforators of the profunda femoris artery, the main vascular pedicle of the lateral thigh flap, pass through the short head of the biceps femoris. Partial excision of the short head of the biceps femoris muscle does not result in any functional disturbance of the leg, and the viability of the buried lateral thigh flap can be monitored by observing the exposed muscle through a small window in the neck. Between April and October 1998 five patients underwent pharyngoesophageal reconstruction by this method. The short head of the biceps femoris was used to monitor the main flap in three patients and to obliterate the dead space after neck dissection in two patients. There were no recipient-site complications such as fistula or infection and no disturbance of thigh function.

Head and neck reconstruction using lateral thigh free flap: flap design

Eleven lateral thigh free flaps were used in head and neck reconstruction, transferred on the basis of the second perforator as well as the third perforator of the profunda femoris artery. The lateral thigh free flap was useful and reliable in head and neck reconstruction and was versatile in flap design. Due to the wide cutaneous territory of the lateral thigh flap, the skin island could be designed freely in the lateral thigh region. Careful patient selection is mandatory for good results. The pinch test and an understanding of the variety of subcutaneous thicknesses in the lateral thigh region are helpful in designing a skin island of adequate thickness. Other considerations in flap design are discussed.

Diastolic shape of the right ventricle of the heart

BACKGROUND

Knowledge of right ventricular (RV) shape is important to the understanding of RV mechanical function and for the improvement of clinically important RV volume estimation techniques. Refinements to the simplest conceptions of RV shape are presented statistically here, based on a quantitative analysis of three-dimensional magnetic resonance (MR) images of excised lamb hearts.

METHODS

The passive shape of the heart in six freshly excised lamb hearts was studied with MR imaging with independent passive pressurization of both ventricles. Global features of shape were assessed, including measurement of short-axis, cross-sectional shape parameters associated with the pinched-arc model.

RESULTS

The slice-area x apex-base length was found to be highly correlated with the volume of the RV, with little sensitivity to the degree of filling of the ventricle or to the exact slice chosen (r = 0.987; n = 22 from five hearts). The RV was shown to follow a clockwise helical path around the left ventricle of 47 +/- 17 degrees, below the outflow tract, as seen from the apical view, progressing from the apex to the base. Based on the pinched-arc model, the anterior arc is shallower than the posterior arc, with a larger radius of curvature and a smaller angle between the arc and the septal axis. As the RV is passively filled, opposite changes in shape occur between the anterior and posterior regions tending to equalize their shapes.

CONCLUSIONS

A high degree of regularity of shape does exist in the RV and, thus, can be characterized effectively in terms of a representative cross-sectional shape and in terms of the changes in that shape proceeding from the base to the apex.

A Patient Self-Checkup App for COVID-19: Development and Usage Pattern Analysis

BACKGROUND

Clear guidelines for a patient with suspected COVID-19 infection are unavailable. Many countries rely on assessments through a national hotline or telecommunications, but this only adds to the burden of an already overwhelmed health care system. In this study, we developed an algorithm and a web application to help patients get screened.

OBJECTIVE

This study aims to aid the general public by developing a web-based application that helps patients decide when to seek medical care during a novel disease outbreak.

METHODS

The algorithm was developed via consultations with 6 physicians who directly screened, diagnosed, and/or treated patients with COVID-19. The algorithm mainly focused on when to test a patient in order to allocate limited resources more efficiently. The application was designed to be mobile-friendly and deployed on the web. We collected the application usage pattern data from March 1 to March 27, 2020. We evaluated the association between the usage pattern and the numbers of COVID-19 confirmed, screened, and mortality cases by access location and digital literacy by age group.

RESULTS

The algorithm used epidemiological factors, presence of fever, and other symptoms. In total, 83,460 users accessed the application 105,508 times. Despite the lack of advertisement, almost half of the users accessed the application from outside of Korea. Even though the digital literacy of the 60+ years age group is half of that of individuals in their 50s, the number of users in both groups was similar for our application.

CONCLUSIONS

We developed an expert-opinion-based algorithm and web-based application for screening patients. This innovation can be helpful in circumstances where information on a novel disease is insufficient and may facilitate efficient medical resource allocation.

Cognitive trio: relationship with major depression and clinical predictors in Han Chinese women

BACKGROUND

Previous studies support Beck's cognitive model of vulnerability to depression. However, the relationship between his cognitive triad and other clinical features and risk factors among those with major depression (MD) has rarely been systematically studied.

METHOD

The three key cognitive symptoms of worthlessness, hopelessness and helplessness were assessed during their lifetime worst episode in 1970 Han Chinese women with recurrent MD. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression.

RESULTS

Compared to patients who did not endorse the cognitive trio, those who did had a greater number of DSM-IV A criteria, more individual depressive symptoms, an earlier age at onset, a greater number of episodes, and were more likely to meet diagnostic criteria for melancholia, postnatal depression, dysthymia and anxiety disorders. Hopelessness was highly related to all the suicidal symptomatology, with ORs ranging from 5.92 to 6.51. Neuroticism, stressful life events (SLEs) and a protective parental rearing style were associated with these cognitive symptoms.

CONCLUSIONS

During the worst episode of MD in Han Chinese women, the endorsement of the cognitive trio was associated with a worse course of depression and an increased risk of suicide. Individuals with high levels of neuroticism, many SLEs and high parental protectiveness were at increased risk for these cognitive depressive symptoms. As in Western populations, symptoms of the cognitive trio appear to play a central role in the psychopathology of MD in Chinese women.

Induction of right ventricular hypertrophy with obstructing balloon catheter. Nonsurgical ventricular preparation for the arterial switch operation in simple transposition

BACKGROUND

Recently, a successful result with a rapid two-stage arterial switch operation (ASO) was reported for patients with transposition of the great arteries (TGA) with low left ventricular pressure. In this procedure, the interval between pulmonary arterial banding and ASO was approximately 1 week. This successful result indicates the possibility of a nonsurgical ventricular preparation procedure using an obstructing balloon catheter prior to ASO.

METHODS AND RESULTS

A 5F atrioseptostomy catheter was inserted directly into the main pulmonary artery in six lambs aged 20 to 38 days. After the chest was closed, the balloon was inflated twice a day for a period of 2 to 2.5 hours. This procedure was performed for 4 consecutive days. After the final inflation, the ratio of right ventricular weight to total ventricular weight was compared with that in an age-matched control group. After the final inflation, the peak systolic right ventricular pressure and the percentage of peak systolic right ventricular to peak systolic aortic pressure rose to 85.6 +/- 4.7 mm Hg (mean +/- 1 SD) and 79.6 +/- 8.6%, respectively. The percentages of the right ventricular weight to the total ventricular weight were significantly higher after the balloon inflation than those in the control group in terms of wet heart weight (29.5 +/- 1.2% versus 23.0 +/- 1.0%; P < .0001) and dry heart weight (27.0 +/- 2.0% versus 21.0 +/- 1.1%; P < .0001).

CONCLUSIONS

The myocardial mass in the right ventricle increased after 4 days of intermittently applied pressure overload. Nonsurgical preparation of the ventricle for ASO in TGA is feasible.

Parallel modified signed-digit arithmetic using an optoelectronic shared content-addressable-memory processor

Addition is the most primitive arithmetic operation in digital computation. Other arithmetic operations such as subtraction, multiplication, and division can all be performed by addition together with some logic operations. With the binary number system, addition speed is inevitably limited by the carry-propagation schemes. On the other hand, carry-free addition is possible when the modified signed-digit (MSD) number representation is used. We propose a novel optoelectronic scheme to handle the parallel MSD addition and subtraction operations. An optoelectronic shared content-addressable memroy is introduced. The shared content-addressable memory uses free-space optical processing to handle the large amount of parallel memory access operations and uses electronics to postprocess and derive logic decisions. We analyze the accuracy that the required optical hardware can deliver by using a statistical cross-talk-rate model that we propose. We also evaluate other important device and system performanceparameters, such as the memory capacity or the maximum number of parallel bits the adder can handle in terms of a given cross-talk rate at a certain repetition rate, the corresponding diffraction-limited memory density, and the system's power efficiency. To confirm the underlining operational principles of the proposed optoelectronic shared content-addressable-memory MSD adder, we design and perform initial experiments for handling 8-bit MSD number addition and subtraction and present the results.

Hepatic safety profile of fosamprenavir-containing regimens in HIV-1-infected patients with or without hepatitis B or C coinfection

PURPOSE

This post hoc analysis investigated the hepatic safety profile of fosampre-navir (FPV) in patients monoinfected with HIV or coinfected with HIV and hepatitis B (HbsAg positive) and/or hepatitis C (anti-HCV antibody positive).

METHODS

Data were pooled from 7 prospective, randomized clinical trials of FPV.

RESULTS

Baseline demographics were generally well-matched between the 205 coinfected (72% HCV, 24% HBV, 3% both) and 1,114 monoinfected patients in this analysis. At baseline, most regimens included ritonavir 100 mg (58%) or 200 mg (38%), and 73% of subjects were ART-naïve. Over 48 weeks, the rate of treatment-related serious adverse events was similar between the coinfected (8%; 16/205) and monoinfected (6%; 62/1114) groups, and the rate of treatment-related grade 2-4 adverse events was higher in the coinfected (38%; 77/205) compared with the monoinfected (29%; 320/1114) group. The percentage of patients with grade 3/4 liver enzyme elevations at any time through week 48 was 14% (ALT) and 12% (AST) in the coinfected group and 1% (both ALT and AST) in the monoinfected group. Median AST to platelet ratio index (APRI) scores decreased by 29% in both groups.

CONCLUSION

Liver enzyme elevations in coinfected patients treated with FPV with or without ritonavir appear generally similar to those reported for other second-generation protease inhibitors.