Clinical and radiographic evaluation of disc excision for lumbar disc herniation with and without posterolateral fusion

STUDY DESIGN

A prospective study evaluating the clinical and radiographic results in 95 patients with lumbar disc herniation.

OBJECTIVES

To evaluate the results of disc excision, with and without posterolateral fusion.

SUMMARY OF BACKGROUND DATA

The effect of posterolateral fusion on the outcomes and radiologic changes in patients with lumbar disc herniation has rarely been reported.

METHODS

Forty-four patients underwent disc excision, and 51 patients underwent disc excision and fusion. Clinical symptoms were evaluated using the Japanese Orthopaedic Association Back scores. All medical and surgical records were examined with regard to intraoperative blood loss, operation time, and other data. Preoperative and follow-up radiographs were analyzed to determine the spinal motion and disc height.

RESULTS

Clinical outcome was excellent or good in 73% of the nonfusion group and in 82% of the fusion group (P = 0.31). The reduction in lower back pain after surgery was greater in the fusion group. The rate of recurrent disc herniation at the surgical level in the nonfusion group increased, but intraoperative blood loss, operation time, length of hospital stay, and total cost of procedure were all significantly less in the patients undergoing disc excision alone than in the fusion group. The radiologic analysis provided evidence that the disc height at the level of disc excision and posterolateral fusion in the fusion group decreased with time, as in the nonfusion group. The changes in disc height and spinal motion were not related to the clinical results.

CONCLUSIONS

Although there is still controversy regarding the pros and cons of fusion in association with disc excision, there is seldom an indication for primary fusion for lumbar disc herniation.

Alternations in atrial natriuretic peptide release after DC cardioversion of non-valvular chronic atrial fibrillation

The response of atrial natriuretic peptide (ANP) release to haemodynamic influences after cardioversion of atrial fibrillation has not been fully examined. We measured plasma concentrations of ANP and assessed haemodynamic changes 60-120 min after DC cardioversion in 22 patients with non-valvular chronic atrial fibrillation. Passive leg elevation to enhance volume expansion was performed 60 min after DC cardioversion. Sinus rhythm was restored in 18 of the 22 patients (successful DC cardioversion group). The control group consisted of seven patients with non-valvular chronic atrial fibrillation who did not undergo DC cardioversion (atrial fibrillation control group). In the successful DC cardioversion group, the mean pulmonary artery wedge pressure decreased significantly 15 min after cardioversion (P < 0.05) and then remained unchanged. Plasma concentrations of ANP also decreased significantly 15 min after cardioversion (P < 0.05). Furthermore, there was an additional significant decrease in ANP levels for up to 60 min after cardioversion (P < 0.05 from 15 min). Passive leg elevation for 15 min led to an increase in the mean pulmonary artery wedge pressure (P < 0.01) and right atrial pressure (P < 0.05), but did not result in increased plasma concentrations of ANP (47.1 +/- 27.6 vs 43.9 +/- 34.4 pg.ml-1, mean +/- SD, P = ns). In the atrial fibrillation control group, passive leg elevation increased the mean pulmonary artery wedge pressure (P < 0.01), the mean right atrial pressure (P < 0.05) and plasma concentrations of ANP (139.9 +/- 85.8 vs 168.1 +/- 108.2, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of low-dose Beraprost sodium, a stable prostaglandin I2 analogue, on reperfusion injury to rabbit lungs

We investigated the effects of low-dose Beraprost sodium (BPS), a stable prostaglandin I2 (PGI2) analogue, on microvascular permeability and the plasma concentrations of thromboxane and adenosine 3',5'-cyclic monophosphate (cAMP) in blood-perfused rabbit lungs subjected to ischemia-reperfusion (I/R). After an ischemic insult for 2 h, saline as a vehicle, 3 pmol/L of BPS (BPS-1), 150 to 300 pmol/L of BPS (BPS-2), 900 pmol/L of BPS (BPS-3), or 60 micromol/L of indomethacin (IND) was administered into the reservoir, then the lungs were reperfused and reventilated for 1 h. Vascular permeability was assessed by determining the microvascular filtration coefficient (Kf, ml/min/mm Hg/100 g wet lung). I/R resulted in increases in vascular resistance, Kf, and thromboxane. BPS-2, BPS-3, and IND inhibited the increase in vascular resistance, and BPS-3 and IND attenuated the increases in Kf and thromboxane. BPS-3 increased, but IND decreased, the concentrations of cAMP in the perfusate. Perfusate thromboxane released after reperfusion was significantly correlated with Kf. We conclude that cyclooxygenase products play a critical role in I/R-induced lung vascular injury and that 900 pmol/L of BPS inhibits the production of thromboxane and enhances the permeability barrier via a cAMP-elevating effect. However, vasodilatory action of BPS may exacerbate the reperfused lung injury by increasing the flow through injured capillaries via inhibition of thromboxane-induced vasoconstriction.

Intermittent oversensing due to internal insulation damage of temperature sensing rate responsive pacemaker lead in subclavian venipuncture method

A 49-year-old male patient developed sensing failure (oversensing) 6 months after the implantation of a temperature sensing rate responsive pacemaker by the subclavian venipuncture method. Intermittent oversensing appeared in the sitting position, but did not appear in the supine position. Temperature telemetry showed an excessive fluctuation of the temperature data points while sitting and while doing a treadmill exercise test. Internal insulation damage was found approximately 31 cm from the distal tip of the explanted lead. The electrical resistance between one thermistor coil and the pacing coil changed from 9 kiloohms to 40 ohms when moderate pressure was applied to the outside lead in the fault area. This electrical shunt resulted from internal insulation damage that resulted from compression of the pacemaker lead between the first rib and the clavicle.

Effect of interstitial edema on lung lymph flow in goats in the absence of filtration

We tested the effect of interstitial edema on lung lymph flow when no filtration occurred. In 16 anesthetized open-thorax ventilated supine goats, we set pulmonary arterial and left atrial pressures to nearly zero and measured lymph flow for 3 h from six lungs without edema and ten with edema. Lymph flow decreased exponentially in all experiments as soon as filtration ceased. In the normal lungs the mean half time of the lymph flow decrease was 12.7 +/- 4.8 (SD) min, which was significantly shorter (P less than 0.05) than the 29.1 +/- 14.8 min half time in the edematous lungs. When ventilation was stopped, lymph flow in the edematous lungs decreased as rapidly as in the normal lungs. The total quantity of lymph after filtration ceased was 2.7 +/- 0.8 ml in normal lungs and 9.5 +/- 6.3 ml in edematous lungs, even though extravascular lung water was doubled in the latter (8.4 +/- 2.4 vs. 3.3 +/- 0.4 g/g dry lung, P less than 0.01). Thus the maximum possible clearance of the interstitial edema liquid by the lymphatics was 6.3 +/- 4.8%. When we restarted pulmonary blood flow after 1-2 h in four additional goats, lymph flow recovered within 30 min to the baseline level. These findings support the hypothesis that lung lymph flow originates mainly from alveolar wall perimicrovascular interstitial liquid and that the contribution of the lung lymphatic system to the clearance of interstitial edema (bronchovascular cuffs, interlobular septa) is small.

Reliability of extravascular lung thermal volume measurements by thermal conductivity technique in sheep

We tested the accuracy, sensitivity, and reproducibility of a new lung water computer, based on the thermal conductivity technique, in 22 anesthetized closed-chest ventilated sheep with different treatments: 1) controls (n = 8), 2) 0.05 ml/kg of oleic acid + 100 ml/kg of lactated Ringer solution (n = 6), and 3) airway instillation of saline [3.1 +/- 1.3 (SD) g/kg, n = 8]. After 4 h, we determined the extravascular lung water gravimetrically. We found a significant overall correlation between the final extravascular lung thermal volume and the gravimetric extravascular lung mass (P < 0.001). Although the average ratio of extravascular lung thermal volume to extravascular lung mass was 0.97 +/- 0.25 ml/g for all groups, the computer overestimated extravascular lung mass in controls by 10% (17 g) and underestimated it in sheep with oleic acid by 15% (95 g) and in sheep with airway instillation by 8% (37 g). The computer also underestimated the small quantities of saline placed via the airway in the alveolar space by 75% (61 g). Reproducibility of three consecutive measurements was 4.3% (SE). We conclude that the thermal conductivity technique has an ability to detect the baseline extravascular lung mass but has a poor ability to detect an accurate increment of the extravascular lung water under poor tissue perfusion in anesthetized ventilated sheep.

Pressure-volume relationships in the pulmonary "venous" system in living dogs

In this study, we examined the pressure-volume (P-V) relationships of the pulmonary "venous" (P'V') system in anesthetized living dogs, and assessed compliance by fitting the derived data of the P-V relationships to the exponential function. By definition, the P'V' system consists of the pulmonary veins and the left atrium. The pulmonary "venous" volume (P'V'V) was determined with our modified double indicator dilution method using a single injection and double sampling technique. The mean left atrial pressure (PLA) was measured directly. To observe sequential changes over a wide range of the P-V relationships, dogs were studied from the control state through the volume-loaded state with dextran. The P'V'V ranged from 3.4 to 12.2 ml X kg-1 and the PLA from 3.2 to 40.6 mmHg. We fitted the data of the P-V relationships (n = 24) to the exponential function, yielding an equation: P'V'V (ml X kg-1) = 19(1-0.833(e-0.017PLA(mmHg)). We then differentiated an above equation to estimate the slope of this curve (static compliance), giving the equation: dV/dP (ml X mmHg-1 X kg-1) = 0.269(e-0.017PLA(mmHg)). Therefore, at PLA of 10 mmHg (normal level), the compliance is 0.227 ml X mmHg-1 X kg-1. The compliance, obtained with an application of the present results in dogs to man, (disregarding expected species differences), coincides well with that in man determined with our indirect method.

Apoptosis in microvascular endothelial cells of perfused rabbit lungs with acute hydrostatic edema

We test the hypothesis that microvascular endothelial cells may undergo apoptosis in response to acute pulmonary venous hypertension. The isolated rabbit lungs were perfused in situ for 4 h with left atrial pressure of 0, 10, or 20 mmHg at a constant blood flow. Edema formation was monitored by lung weight gain. To assay for apoptosis, we performed agarose gel electrophoresis of DNA, in situ nick end labeling of DNA strand breaks, and electron microscopy. We also examined the levels of expression of Bcl-2, a suppressor of apoptosis, in microvascular endothelial cells using an immunohistochemical technique. In a vascular pressure-dependent fashion, we found apoptosis in endothelial cells of alveolar septal capillaries, as well as expression of Bcl-2 in arteriolar and venular endothelial cells. We conclude that acute pulmonary venous hypertension induces apoptosis in capillary endothelial cells but not in arteriolar and venular endothelial cells, suggesting that microvascular endothelial cell apoptosis is dependent on the levels of Bcl-2 expression and influences the formation or resolution of acute hydrostatic lung edema.

Increases in Urinary Enzyme Excretion in Rats Depleted of Glutathione Inhibited by Scavenger of Oxygen Free Radicals

Urinary excretion of enzymes by rats was assessed after glutathione (GSH) was depleted by treatment with a mixture of the GSH depletors D,L-buthionine-S,R-sulfoximine (BSO) and diethylmaleate (DEM). Renal GSH was low 2 h after treatment and later returned to the control level. The urinary excretion of gamma-glutamyltranspeptidase (gamma-GTP) and N-acetyl-beta-D-glucosaminidase (NAG) remained high for at least 3 d after the injection of BSO (100 mg/kg) and DEM (0.5 ml/kg), with no effect on the blood urea nitrogen level. N,N'-Dimethylthiourea (DMTU), a scavenger of oxygen free radicals, inhibited this increase in the urinary excretion of gamma-GTP. DMTU also inhibited the increase in cisplatin-induced NAG excretion caused by the GSH depletors. These results suggested that the urinary excretion of these enzymes is an index of renal tubular injury caused by short-term depletion of renal GSH, and that the generation of free radicals may be involved in renal tubular injury during GSH depletion or caused by cisplatin together with GSH depletors.

Impact of repetitive thought and processing mode on goal striving

BACKGROUND AND OBJECTIVES

Striving to attain personal goals is important for maintaining well-being. Previous research indicates that repetitive thoughts can influence the affect and cognition associated with personal goal strivings. Repetitive thought in the concrete-experiential processing mode improves affect and cognition after a negative event more than does repetitive thought in the abstract-analytic processing mode. We extend this prior work by examining whether repetitive thought directly influences the maintenance of personal goal strivings through a longitudinal survey.

METHODS

In Study 1, we examined the daily maintenance effect of repetitive thought on personal goal strivings using a multilevel analysis of 29 participants who reported their thoughts and goal strivings daily for one week. In Study 2, participants (N = 131) reported their thoughts and goal strivings over 10 weeks, and we examined the maintenance effect of repetitive thought on personal goal strivings every two weeks.

RESULTS

Highly repetitive thought in the abstract-analytic processing mode decreased the maintenance of short-term personal goal strivings in individuals with difficult goals. However, highly repetitive thought in the concrete-experiential processing mode increased the maintenance of long-term personal goal strivings in individuals with difficult goals.

LIMITATIONS

The study participants were university students; therefore, we cannot generalize the results to clinical populations or other age groups.

CONCLUSION

Interventions that increase repetitive thought in the concrete-experiential processing mode may be effective in facilitating long-term goal strivings in individuals attempting to overcome difficult situations and achieve important personal goals.

Application of respiratory heat exchange for the measurement of lung water

A noninvasive method for measuring pulmonary blood flow and lung mass (called airway thermal volume), based on the measurements of lung heat exchange with environment, is described. The lungs function as a steady-state heat exchange system, having an inner heat source (pulmonary blood flow) and an external heat sink (ventilation). Sudden changes in the steady-state condition, such as caused by hyperventilation of dry air, lead to a new steady state after a few minutes. The expired air temperature difference between the initial and final steady states is proportional to pulmonary blood flow, whereas the rate at which the new steady state is achieved is proportional to airway thermal volume. The method was tested in 20 isolated dogs lungs, 9 perfused goat lungs, and 27 anesthetized sheep. The expired air temperature fall during hyperventilation was inversely proportional to the perfusion rate of the isolated lungs, and half-time of the temperature fall was proportional to the lung tissue mass. Experiments in anesthetized sheep showed that the measured airway thermal volume is close to the total mass of the excised lungs, including its residual blood (r = 0.98). Pulmonary edema and fluid instillation into the bronchial tree increased in the measured lung mass.

Pretreatment with catalase or dimethyl sulfoxide protects alloxan-induced acute lung edema in dogs

We tested the preventive effects of catalase, an enzymatic scavenger of hydrogen peroxide, or dimethyl sulfoxide (DMSO), a hydroxyl radical scavenger, on intravenous alloxan-induced lung edema in four groups of pentobarbital sodium-anesthetized, ventilated dogs for 3 h: saline (20 ml.kg-1.h-1) infusion alone (n = 5), alloxan (75 mg/kg) + saline infusion (n = 5), catalase (150,000 U/kg) + alloxan + saline infusion (n = 5), or DMSO (4 mg/kg) + alloxan + saline infusion (n = 5). Catalase or DMSO significantly prevented the increase in plasma thromboxane B2 and 6-keto-prostaglandin F1 alpha over 3 h after alloxan and the accumulation of extravascular lung water after 3 h [3.95 +/- 0.52 (SE) g/g with catalase, 3.06 +/- 0.42 g/g with DMSO] but not early pulmonary arterial pressor response. An electron microscopic study indicated that catalase or DMSO significantly reduced the endothelial cellular damages after alloxan. These findings strongly suggest that hydrogen peroxide and hydroxyl radical are major mediators responsible for intravenous alloxan-induced edematous lung injury in anesthetized ventilated dogs.

Intracytoplasmic crystalloid structures in a malignant fibrous histiocytoma: ultrastructural and cytochemical study

Crystalloid structures were frequently observed in the cytoplasm of the tumor cells of a malignant fibrous histiocytoma arising in the left leg of a 71-year-old female. These structures were located in the cytoplasm of the fibroblastlike and histiocyte-like tumor cells. The structures consisted of an aggregate of dense granules without unit membrane. Neither glycoproteins nor polysaccharides were detected in these structures on sections stained with chromic acid-phosphotungstic acid or periodic acid-thiocarbohydrazide-silver proteinate. On sections from acrylate-embedded specimens, the structures were easily digested by trypsin and protease but were not sensitive to RNase. Although the significance and origin of these structures remain obscure, the results indicate that the crystalloid structures in the present study are mainly composed of proteinaceous substance.

The importance of ligand gated ion channels in sleep and sleep disorders

On average, humans spend about 26 years of their life sleeping. Increased sleep duration and quality has been linked to reduced disease risk; however, the cellular and molecular underpinnings of sleep remain open questions. It has been known for some time that pharmacological modulation of neurotransmission in the brain can promote either sleep or wakefulness thereby providing some clues about the molecular mechanisms at play. However, the field of sleep research has developed an increasingly detailed understanding of the requisite neuronal circuitry and key neurotransmitter receptor subtypes, suggesting that it may be possible to identify next generation pharmacological interventions to treat sleep disorders within this same space. The aim of this work is to examine the latest physiological and pharmacological findings highlighting the contribution of ligand gated ion channels including the inhibitory GABA_A and glycine receptors and excitatory nicotinic acetylcholine receptors and glutamate receptors in the sleep-wake cycle regulation. Overall, a better understanding of ligand gated ion channels in sleep will help determine if these highly druggable targets could facilitate a better night's sleep.

A problem in the measurements of pulmonary extravascular water volume by double indicator dilution method, using heat and dye--thermal diffusion into the left ventricular wall

Pulmonary extravascular water volume was obtained as the lung thermal volume (LTV) in mongrel dogs (n = 31) by double indicator dilution method, using negative heat and indocyanine green. We used a technic of one injection site (right atrium) and two sampling sites, i.e., pulmonary artery trunk and aortic root. In 13 dogs, cardiac outputs determined simultaneously from thermodilution curves in pulmonary artery trunk, aortic root and from dye dilution curve in aortic root, were in a good agreement with a coefficient of variation of +/- 12%. Lung thermal volume measured twice within a period of 5 minutes in 17 dogs, gave closely similar values with a coefficient of variation of +/- 9%. Lung thermal volume was 5.7 +/- 1.1 ml/kg (mean +/- SD) and corresponding "weighed lung water" (WLW), which was measured by destructive, direct method, was 5.0 +/- 1.0 ml/kg, the ratio of LTV to WLW (LTV/WLW) being 1.2 +/- 0.2 in control state. LTV/WLW ratio was 1.2 +/- 0.2 in 11 dogs loaded with dextran, and 1.1 +/- 0.1 in 6 dogs loaded with alloxan. Thus the lung thermal volume slightly exceeded WLW. In order to evaluate the extent to which the thermal diffusion into the left ventricular wall would cause LTV to slightly overestimate the pulmonary extravascular water volume, dye dilution curves and thermodilution curves were recorded simultaneously in the left atrium (LA) and aortic root (Ao) in a total of 25 runs in 5 dogs. The ratio of LTV obtained in LA to that in Ao was 0.9 +/- 0.1 (mean +/- SD). It was concluded that the pulmonary extravascular water volume was overestimated, by about 10% due to the thermal diffusion into the left ventricular wall.

Correction for apparent prolongation of mean transit time resulting from response time in a thermodilution system

We investigated a method of correcting an apparent prolongation in the measured mean transit time (MTT), resulting from the response time of the thermodilution system. We measured the mean response times (MRT) for five commercially available thermistor-tipped catheters by recording their step function response curves. MRT is the sum of the time from the point of step change to the point of the first detection of change in temperature (latency time) plus the time from the first detection to the point of 63.2% of full response (time constant). By using a flow loop model filled with saline through a mixing chamber, we recorded pairs of thermodilution curves simultaneously with pairs of catheters, and studied the influence of MRT on MTT over the constant flow rates of 1-6 L/min. The difference in MRT's (delta MRT, second) between a pair of thermodilution systems correlated with the difference in MTT's (delta MTT, second) between a corresponding pair of thermodilution curves, yielding an equation: delta MTT = 1.07 delta MRT = 0.04 (n = 72, r = 0.95), delta MTT/delta MRT = 1.02 +/- 0.18 (mean +/- SD). We conclude that an apparent prolongation of MTT due to response time is removable by subtracting MRT from measured MTT.

Insect water-specific aquaporins in developing ovarian follicles of the silk moth Bombyx mori: role in hydration during egg maturation

Egg formation in terrestrial insects is an absorptive process, accommodated not only by packing proteins and lipids into yolk but also by filling chorions with water. An osmotic swelling of ovarian follicles takes place during oocyte maturation. This study investigated the role of the aquaporin (AQP) water channel in the osmotic uptake of water during oogenesis in the silk moth Bombyx mori Linnaeus, 1758. Using the antibodies that specifically recognize previously characterized AQPs, two water-specific subtypes-AQP-Bom1 and AQP-Bom3-belonging to the Drosophila integral protein (DRIP) and Pyrocoelia rufa integral protein (PRIP) subfamilies of the insect AQP clade, respectively, were identified in the developing ovaries of B. mori. During oocyte growth, Bombyx PRIP was distributed at the oocyte plasma membrane, where it likely plays a role in water uptake and oocyte swelling, and may be responsible for oocyte hydration during fluid absorption by ovarian follicles. During the transition from vitellogenesis to choriogenesis during oocyte maturation, Bombyx DRIP expression became abundant in peripheral yolk granules underlying the oocyte plasma membrane. The restricted DRIP localization was not observed in non-diapause-destined follicles, where DRIP was evenly distributed in medullary yolk granules. There was no difference in PRIP distribution between diapause- and non-diapause-destined follicles. The diapause-destined oocytes encase DRIP protein in the peripheral yolk granules, where DRIP might be inert. This would be reflected in the metabolic arrest associated with diapause after fertilization and egg oviposition.

Do Self-Compassion Factors Affect Value-Based Behavior Promotion for Adolescents? The Context of Behavioral Activation

Behavioral activation has been shown to engender improvement of depressive symptoms. Behavioral activation specifically addresses behavioral patterns that maintain depressive symptoms and increases activation of rewarding behaviors based on a person’s own values. Nevertheless, behaving according to those values can be difficult. Consequently, discussing reduction in barriers to activation of value-based behaviors is important. Self-compassion might promote value-based behavior when a person confronts some obstacle. We evaluated differences in self-compassion and behavioral characteristics at high and low levels of value-based behaviors. Furthermore, we examined relations of self-compassion to value-based behaviors while considering activation, avoidance, and positive reinforcement in the context of behavioral activation. All 800 university student participants (415 women, 385 men; mean age=20.47years; age range 18–24years) in this study completed assessments. Descriptive statistics, MANOVA, and stepwise regression analysis relations elucidated their value-based behavior, self-compassion, and behavioral characteristics. Results suggest that participants who behaved according to values had high levels of self-kindness, common humanity, and mindfulness. Results of stepwise regression analyses suggest as a new finding that positive components of self-compassion (self-kindness, common humanity, and mindfulness) are related to value-based behaviors even when behavioral factors are considered in the context of behavioral activation.

A problem intrinsic to the measurements of the pulmonary extravascular water volume by the thermal-dye technic with the sampling site in the bifurcation of the aorta. Thermal equilibrium with the aortic wall

When estimating the pulmonary extravascular water volume (PEWV) as the lung thermal volume (LTV), by the double indicator dilution technic using heat and indocyanine green (ICG), a part of the left ventricular wall comes to the thermal equilibrium, and this leads to an overestimation of PEWV, when the samplings are made in the aortic root. In a previous study from this laboratory, this overestimation was approximately 10% of the measured LTV in the aortic root. In the present study, we evaluated the extent to which the thermal equilibrium with the aortic wall would cause LTV to slightly overestimate PEWV. For this purpose, we injected a mixture of the indicators into the right atrium, and recorded the indicator dilution curves at the bifurcation of the aorta (AB). We then compared this LTV with the one calculated from the indicator dilution curves recorded simultaneously in the aortic root (Ao). We obtained the following results: Firstly, the values of cardiac output (CO) from the dye dilution curve and from the thermodilution curve at two sites, Ao and AB, were all in agreement. Secondly, LTV estimated in Ao (LTVAo) and LTV estimated in AB (LTVAB) were not the same, and their relationships were: LTVAB = 1.21 X LTVAo + 0.44 (ml/kg), n = 32, (r = 0.98, p less than 0.001) A close agreement of CO determined at two sites indicated that there was virtually no loss of heat between the two sampling sites, Ao and AB. An excess of LTVAB over LTVAo came to about 20%, and this excess appeared to be ascribable to the incorporation of the thermally equilibrated "volume" of the aortic wall. This finding appeared to be a challenge to the validity of estimating LTV when sampling the indicators in the distal abdominal aorta.

Pulmonary blood volume and pulmonary extravascular water volume in men

In order to estimate the pulmonary blood volume between the pulmonary artery trunk and the left atrium (PBV PAT-LA), simultaneously with the pulmonary extravascular water volume (PEWV) in the chronically stable cardiac patients, we employed the double indicator dilution method using heat as a diffusible indicator and indocyanine green as a non-diffusible indicator. The PEWV was obtained as the extravascular lung thermal volume estimated in the aortic root (LTVAo). In the group of hemodynamically normal patients, in spite of ischemic heart disease (G-N, n = 22), the mean pulmonary artery wedge (PAW) pressure was 9.3 +/- 3.9 mmHg (mean +/- SD), PBVPAT-LA was 8.95 +/- 1.71 ml/kg, LTVAo was 5.71 +/- 1.37 ml/kg and PBVPAT-LA/LTVAo ratio was 1.64 +/- 0.44. In the group of hemodynamically slightly compromised patients with mitral stenosis (G-MS, n = 13), the mean PAW pressure was 14.2 +/- 2.6 mmHg, PBVPAT-LA was 11.12 +/- 2.86 ml/kg, LTVAo was 5.68 +/- 1.41 ml/kg and PBVPAT-LA/LTVAo ratio was 2.02 +/- 0.58. Between the two groups, LTVAo was not statistically significant, whereas the mean PAW pressure, PBVPAT-LA and PBVPAT-LA/LTVAo ratio were all significantly increased in G-MS (p less than 0.05). Neither PBVPAT-LA nor LTVAo correlated with the mean PAW pressure in both groups. From PBVPAT-LA/LTVAo ratio, fluid volume in the intravascular space was greater than that in the extravascular space in both groups. From LTVAo, PEWV in G-MS was identical with that in G-N, in spite of the elevated mean PAW pressure. Therefore, even in the patients with mitral stenosis, the interstitium in the lung is kept "dry" under conditions of the mean PAW pressure below 20 mmHg. The safety factors that prevent pulmonary edema, as evidenced in animal studies, seem to operate effectively in man.

Effects of acetylsalicylic acid on pulmonary vascular tone and membrane permeability in blood-perfused dog lung

We studied the effects of acetylsalicylic acid (ASA) on pressor response, microvascular filtration coefficient (Kf), extravascular lung water, and plasma concentrations of cyclooxygenase- and 5-lipoxygenase-derived products in 21 blood-perfused dog lungs with constant flow. The lungs were perfused for 1 h with an intrapulmonary injection of saline as vehicle (n = 5), a low dose of ASA [136 +/- 25 (SD) micrograms/ml perfusate; n = 5], a high dose of ASA (1,006 +/- 278 micrograms/ml perfusate; n = 6), or alloxan (1,000 mg; n = 5). Alloxan significantly increased Kf and extravascular lung water, whereas neither the low nor high dose of ASA increased Kf or extravascular lung water. The ASA-induced increase in vascular resistance did not correlate with the extent of the decrease in perfusate 6-keto-prostaglandin F1 alpha or the ratio of perfusate 6-ketoprostaglandin F1 alpha to thromboxane B2. Moreover, ASA did not enhance the generation of perfusate leukotrienes B4, D4, or E4. We conclude that pulmonary microvascular permeability is unaltered by ASA and that neither the decrease in plasma prostacyclin nor the increase in plasma sulfidopeptide leukotrienes may account for ASA-induced pulmonary vasoconstriction.

Trace of depression: network structure of depressive symptoms in different clinical conditions

Background

Psychopathological network model has received attention recently in the traditional debate about the continuity of depression. However, there is little evidence for comparing the network structure of depressive symptoms in several depressive states at different clinical stages. Through this study of a broad sample of patients with nonclinical to clinical depression, we examined differences in the network structure of depressive symptoms.

Methods

Four groups of participants, including cohorts of clinical depression (current depression, n  = 294; remitted depression, n  = 118) and nonclinical depression (subthreshold depression, N  = 184; healthy control, n  = 257), responded to Beck Depression Inventory-II (BDI-II). After adjusting for age and sex, the residual scores of the 21 BDI-II items were input into a regularized partial correlation network for each group. Then, the estimated edge strengths/densities and node characteristics were compared.

Results

Current depression has a discontinuous structure with a stronger and denser network of symptoms compared with nonclinical groups. Interestingly, remitted depression had improved to the level in healthy controls; however, it retained the same network structure as current depression, which indicates a trace of depression.

Conclusions

We found the traces of depression that remained even after the symptoms disappeared. This study might provide a novel framework for elucidating the development and formation of depression.

Effects of ventilation and pleural effusion on measurements of airway thermal volume and blood flow in dog lungs

We studied the effects of ventilation and pleural effusion on measurements of airway thermal volume (ATV) and pulmonary blood flow (PBF) by using the airway gas thermometry method of V. B. Serikov, M. S. Rumm, K. Kambara, M. I. Bootomo, A. R. Osmack, and N. C. Staub (J. Appl. Physiol. 72: 944-953, 1992) in 39 anesthetized dogs with or without lung edema or pleural effusion. To examine the differential effects of increased-pressure and increased-permeability lung edema on accuracy and sensitivity of ATV and PBF, two models of lung edema were induced by intravenous infusion of a Dextran 70 solution and alloxan monohydrate, respectively. Dogs were hyperventilated for 3 min by using a wide range of minute ventilation (VE) to produce two steady-state conditions of airway temperature. Higher levels of VE increased an estimated amount of ATV. The ATV produced by hyperventilation at VE values of 559, 158, and 72 ml.min-1.kg-1 was consistent with the gravimetric total lung mass, the blood-free wet lung weight, and the extravascular lung water volume, respectively. The coefficient of lung thermal conductivity, a practical index of the rate of heat conduction through tissue from lung vessels, was related to the ratio of the decrease in expired air temperature to VE, and estimated PBF was consistent with the thermodilution cardiac output. Pleural effusion had little effect on measurements of ATV and PBF. However, ATV and PBF showed increased variation in dogs with dextran-induced lung edema.