Significant Changes In Cross-sectional Area Research Articles

Application of ultrasound images-based radiomics in carpal tunnel syndrome: Without measuring the median nerve cross-sectional area.

By constructing a prediction model of carpal tunnel syndrome (CTS) based on ultrasound images, it can automatically and accurately diagnose CTS without measuring the median nerve cross-sectional area (CSA). A total of 268 wrists ultrasound images of 101 patients diagnosed with CTS and 76 controls in Ningbo NO.2 Hospital from December 2021 to August 2022 were retrospectively analyzed. The radiomics method was used to construct the Logistic model through the steps of feature extraction, feature screening, reduction, and modeling. The area under the receiver operating characteristic curve was calculated to evaluate the performance of the model, and the diagnostic efficiency of the radiomics model was compared with two radiologists with different experience. The 134 wrists in the CTS group included 65 mild CTS, 42 moderate CTS, and 17 severe CTS. In the CTS group, 28 wrists median nerve CSA were less than the cut-off value, 17 wrists were missed by Dr. A, 26 wrists by Dr. B, and only 6 wrists were missed by radiomics model. A total of 335 radiomics features were extracted from each MN, of which 10 features were significantly different between compressed and normal nerves, and were used to construct the model. The area under curve (AUC) value, sensitivity, specificity, and accuracy of the radiomics model in the training set and testing set were 0.939, 86.17%, 87.10%, 86.63%, and 0.891, 87.50%, 80.49%, and 83.95%, respectively. The AUC value, sensitivity, specificity, and accuracy of the two doctors in the diagnosis of CTS were 0.746, 75.37%, 73.88%, 74.63% and 0.679, 68.66%, 67.16%, and 67.91%, respectively. The radiomics model was superior to the two-radiologist diagnosis, especially when there was no significant change in CSA. Radiomics based on ultrasound images can quantitatively analyze the subtle changes in the median nerve, and can automatically and accurately diagnose CTS without measuring CSA, especially when there was no significant change in CSA, which was better than radiologists.

Histomorphological and inflammatory changes of white adipose tissue in gastrointestinal cancer patients with and without cachexia.

BackgroundDuring cancer cachexia, several alterations occur in peripheral tissues, and the adipose tissue may be involved during the catabolic state. We aimed at investigating histological rearrangement and infiltration of inflammatory cells in subcutaneous adipose tissue (SAT) of patients with cancer undergoing surgery, according to the presence/absence of cachexia.MethodsWe considered gastrointestinal cancer patients and controls with non‐malignant diseases undergoing surgery. We collected SAT samples and performed histomorphological analyses [cross‐sectional area (CSA) and per cent of fibrosis] and immunohistochemistry to characterize the inflammatory cells. By computed tomography (CT) scan, we calculated SAT and visceral adipose tissue (VAT).ResultsWe enrolled 51 participants (31 gastrointestinal cancer patients and 20 controls). In cancer patients, cachexia was present in 13/31 (42%). The CSA (μm2) of the adipocytes from SAT was reduced in cancer patients vs. controls (3148, inter‐quartile range 2574–3755 vs. 4474, inter‐quartile range 3654–5183) (P < 0.001), in particular in cachectic patients vs. non‐cachectic (median 2518 vs. median 3470) (P = 0.03) and in cachectic vs. controls (P < 0.001), as well as in non‐cachectic vs. controls (P = 0.04). The median per cent of fibrosis was higher in cancer patients vs. controls (9 vs. 3) (P = 0.0001), in particular in cachectic vs. non‐cachectic (13.35 vs. 7.13) (P = 0.03). We observed a higher number of macrophages (CD68) (P = 0.0001) and T lymphocytes (CD3) (P = 0.002) in SAT of cancer patients vs. controls, and the number of T lymphocytes was higher in cachectic vs. non‐cachectic patients (P = 0.025). Anorexic cancer patients showed in SAT a higher number of macrophages and T lymphocytes with respect to controls (P < 0.0001), whereas no difference was present between anorexic and non‐anorexic patients. At CT scan, cachectic patients showed lower VAT and SAT vs. non‐cachectic (VAT: 97.64 ± 40.79 vs. 212.53 ± 79.24, P = 0.0002; SAT: 126.27 ± 87.92 vs. 206.27 ± 61.93, P = 0.01, respectively). Cancer patients with low CSA, high degree of fibrosis, and high number of T lymphocytes presented with lower body mass index and lower SAT and VAT at CT scan (P ≤ 0.01).ConclusionsWe found histological alterations of SAT among gastrointestinal cancer patients and in particular significant changes in CSA, fibrosis, and inflammation when cachexia was present; the changes in histomorphological parameters of the adipocytes reflected alterations in adiposity at body composition analysis.

Low-Load Resistance Training Performed to Muscle Failure or Near Muscle Failure Does Not Promote Additional Gains on Muscle Strength, Hypertrophy, and Functional Performance of Older Adults.

Bergamasco, JGA, Gomes da Silva, D, Bittencourt, DF, Martins de Oliveira, R, Júnior, JCB, Caruso, FC, Godoi, D, Borghi-Silva, A, and Libardi, CA. Low-load resistance training performed to muscle failure or near muscle failure does not promote additional gains on muscle strength, hypertrophy, and functional performance of older adults. J Strength Cond Res 36(5): 1209-1215, 2022-The aim of the present study was to compare the effects of low-load resistance training (RT) protocols performed to failure (FAI), to voluntary interruption (VOL), and with a fixed low repetitions (FIX) on muscle strength, hypertrophy, and functional performance in older adults. Forty-one subjects (60-77 years) were randomized into one of the RT protocols (FAI, VOL, or FIX) and completed 12 weeks of RT at 40% of 1 repetition maximum (1RM), twice a week. The assessments included 1RM test, muscle cross-sectional area (CSA), rate of torque development (RTD), and functional performance (chair stand [CS], habitual gait speed [HGS], maximal gait speed [MGS], and timed up-and-go [TUG]). All protocols significantly increased 1RM values from Pre (FAI: 318.3 ± 116.3 kg; VOL: 342.9 ± 93.7 kg; FIX: 328.0 ± 107.2 kg) to Post (FAI: 393.0 ± 143.1 kg, 23.5%; VOL: 423.0 ± 114.5 kg, 23.3%; FIX: 397.8 ± 94.6 kg, 21.3%; p < 0.0001 for all groups). Regarding CS, all protocols showed significant improvements from Pre (FAI: 11.5 ± 2.4 seconds; VOL: 12.1 ± 2.5 seconds; FIX: 11.3 ± 1.1 seconds) to Post (FAI: 10.5 ± 1.1 seconds, -8.5%, p = 0.001; VOL: 10.3 ± 1.5 seconds, -15.1%, p = 0.001; FIX: 11.0 ± 1.1, -3.2%, p = 0.001). Habitual gait speed values increased significantly from Pre (FAI: 1.3 ± 0.2 m·s-1; VOL: 1.3 ± 0.1 m·s-1; FIX: 1.3 ± 0.1 m·s-1) to Post (FAI: 1.4 ± 0.2 m·s-1, 2.5%, p = 0.03; VOL: 1.4 ± 0.2 m·s-1, 5.2%, p = 0.036; FIX: 1.4 ± 0.1 m·s-1, 5.7%, p = 0.03). No significant differences between protocols were found (p > 0.05). In addition, there were no significant changes in CSA, RTD, MGS, and TUG for any protocols (p > 0.05). In conclusion, low-load RT performed without muscle failure promotes significant improvements in muscle strength and some parameters of functional performance in older adults.

Abstract 140: Vascular Structure in Brain: Lack of Small Vessel Recovery Following Hypertension

Vascular remodeling is a feature of small vessel disease (SVD), predictive of vascular events, brain injury, and cognitive decline. Hypertension alters vascular structure including diameter and cross-sectional area (CSA) of the vessel wall. While effects of hypertension on large arteries have been studied relatively widely, detailed quantification, including recovery from hypertension in microvessels, is rare. Previously, angiotensin II (Ang II)-dependent hypertension produced increased CSA but reduced internal diameter (ID) of cerebral arterioles (inward remodeling) in brain. Because cerebral arterioles are targets of SVD, we examined the hypothesis that brain microvessels can recover from hypertension after return of mean arterial pressure (MAP) to normal levels. MAP was measured using radiotelemetry in adult male C57BL6J mice at baseline, during infusion of vehicle or Ang II (1.4 mg/kg per day using osmotic mini-pumps) for 28 days, and during a 28 day recovery period (n=5 in each group). Prior to treatment, MAP was similar in both groups, with MAP remaining stable in vehicle treated mice. With Ang II treatment, MAP began to rise on day 3, steadily increasing until day 28. On day 30, MAP began to decrease, reaching levels seen with vehicle on days 46-47. In anesthetized mice, we measured pressure, diameter, and CSA of the vessel wall in maximally dilated arterioles (baseline diameter of 62±3 microns) at 1, 3, 7, 14, 28, and 56 days after pump implantation (n=7-9 in each group). At day 1, ID and CSA were similar in both groups. With vehicle, there was no significant change in CSA or ID at any time point. With Ang II, CSA increased at day 7 and was maintained at days 14 and 28 (P=0.023). ID did not change at day 3 or 7, but was reduced (by ~15%, P=0.011) at 14 and 28 days. During recovery (day 56), CSA returned 63% of the way to normal (compared to vehicle), while ID remained at day 14 and 28 values. In conclusion, CSA changed rapidly during hypertension onset and largely recovered with a reduction in MAP. Inward remodeling developed slowly and did not recover after return of MAP to control levels. The lack of recovery after hypertension has implications for the impact of SVD including hypoperfusion, impaired vasodilation, and augmented injury during ischemia.

Effects of neuromuscular electrical stimulation training on muscle size in collegiate track and field athletes

The purpose of this study was to examine the effects of neuromuscular electrical stimulation training for 12 weeks on the abdominal muscle size in trained athletes. Male collegiate track and field athletes participated in the present study and were randomly allocated to either training or control groups. Eleven participants of the training group completed a 60-session training program over a 12-week period (23 min/session, 5 days/week) involving neuromuscular electrical stimulation (mostly 20 Hz) for the abdominal muscles in addition to their usual training for the own events. The participants of the control group (n = 13) continued their usual training. Before and after the intervention period, cross-sectional areas of the rectus abdominis and abdominal oblique muscles (the internal and external obliques and transversus abdominis) and subcutaneous fat thickness were measured with magnetic resonance and ultrasound imaging. There were no significant changes in cross-sectional area of the rectus abdominis or abdominal oblique muscles or in subcutaneous fat thickness in the training or control groups after the intervention period. The change in cross-sectional area of the rectus abdominis in each participant was not significantly correlated with pre-training cross-sectional area and neither was the mean value of fat thickness at pre- and post-training. These results suggest that low-frequency (20 Hz) neuromuscular electrical stimulation training for 12 weeks is ineffective in inducing hypertrophy of the abdominal muscles in trained athletes, even when they have a thin layer of subcutaneous fat.

Abstract P3004: Brain Microvascular Structure During Hypertension: Temporal Changes and Recovery Support Distinct Arteriolar Mechanisms

Hypertension alters vascular structure including diameter, cross-sectional area (CSA), and stiffness of the vessel wall. Inward remodeling is a feature of small vessel disease (SVD), predictive of vascular events and cognitive decline. While effects of prevention of hypertension on large arteries have been studied widely, quantification of temporal changes and recovery from hypertension in microvessels is rare. Previously, angiotensin II (Ang II)-dependent hypertension produced increased CSA but reduced internal diameter (ID) of maximally dilated arterioles (inward remodeling) in brain. Because cerebral arterioles are targets of SVD, we examined time course and whether microvessels recover from hypertension. Mean arterial pressure (MAP) was measured using radiotelemetry in adult male C57BL6J mice prior to, during infusion of vehicle or Ang II (1.4 mg/kg per day using osmotic mini-pumps) for 28 days, and a 28 day recovery period. Prior to treatment, MAP was similar in both groups. Throughout recording, MAP was stable in vehicle treated mice. With Ang II, MAP began to rise on day 3, steadily increasing until day 28. On day 30, MAP began to decrease, reaching levels seen with vehicle on days 46-47. In anesthetized mice, we measured pressure, diameter, and CSA of the vessel wall (histologically) in maximally dilated arterioles (baseline diameter of 63±1 microns) at 1, 3, 7, 14, 28, and 56 days after pump implantation (n=7-9 in each group). At day 1, ID and CSA were similar in both groups. With vehicle, there was no significant change in CSA or ID at any time point. With Ang II, CSA increased at day 7 and was maintained at days 14 and 28 (P=0.023). ID did not change at day 3 or 7, but was reduced (by ~15%, P=0.011) at 14 and 28 days. During recovery (day 56). CSA returned 63% of the way to normal (compared to vehicle), while ID remained at day 14 and 28 values. In conclusion, CSA changed rapidly during hypertension onset and largely recovered with a reduction in MAP. Inward remodeling developed slowly and did not return to vehicle levels with MAP. The lack of recovery of ID after a period of hypertension has implications for the impact of SVD including hypoperfusion, impaired vasodilation, and augmented injury during ischemia.

Changes in lower extremity blood flow during advancing phases of pregnancy and the effects of special footwear.

Background During pregnancy, a number of changes affecting venous blood flow occur in the circulatory system, such as reduced vein wall tension or increased exposure to collagen fibers. These factors may cause blood stagnation, swelling of the legs, or endothelial damage and consequently lead to development of venous disease. Objectives The aim of this study is to evaluate the effect of special footwear designed to improve blood circulation in the feet on venous blood flow changes observed during advancing phases of pregnancy. Methods Thirty healthy pregnant women participated in this study at 25, 30, and 35 weeks of gestation. Participants were allocated at random to an experimental group (n = 15) which was provided with the special footwear, or a control group (n = 15). At each data collection session, Doppler measurements of peak systolic blood flow velocity and cross-sectional area of the right popliteal vein were performed using a MySonoU6 ultrasound machine with a linear transducer (Samsung Medison). The differences were compared using Cohen’s d test to calculate effect size. Results With advancing phases of pregnancy, peak systolic velocity in the popliteal vein decreased significantly in the control group, whereas it increased significantly in the experimental group. No significant change in cross-sectional area was observed in any of the groups. Conclusions Findings in the experimental group demonstrated that wearing the footwear tested may prevent venous blood velocity from reducing during advanced phases of pregnancy. Nevertheless, there is a need for further investigation of the beneficial effect on venous flow of the footwear tested and its application.

Muscle sparing in muscle RING finger 1 null mice: response to synthetic glucocorticoids

Skeletal muscle atrophy occurs under a variety of conditions and can result from alterations in both protein synthesis and protein degradation. The muscle-specific E3 ubiquitin ligases, MuRF1 and MAFbx, are excellent markers of muscle atrophy and increase under divergent atrophy-inducing conditions such as denervation and glucocorticoid treatment. While deletion of MuRF1 or MAFbx has been reported to spare muscle mass following 14 days of denervation, their role in other atrophy-inducing conditions is unclear. The goal of this study was to determine whether deletion of MuRF1 or MAFbx attenuates muscle atrophy after 2 weeks of treatment with the synthetic glucocorticoid dexamethasone (DEX). The response of the triceps surae (TS) and tibialis anterior (TA) muscles to 14 days of DEX treatment (3 mg kg(-1) day(-1)) was examined in 4 month-old male and female wild type (WT) and MuRF1 or MAFbx knock out (KO) mice. Following 14 days of DEX treatment, muscle wet weight was significantly decreased in the TS and TA of WT mice. Comparison of WT and KO mice following DEX treatment revealed significant sparing of mass in both sexes of the MuRF1 KO mice, but no muscle sparing in MAFbx KO mice. Further analysis of the MuRF1 KO mice showed significant sparing of fibre cross-sectional area and tension output in the gastrocnemius (GA) after DEX treatment. Muscle sparing in the MuRF1 KO mice was related to maintenance of protein synthesis, with no observed increases in protein degradation in either WT or MuRF1 KO mice. These results demonstrate that MuRF1 and MAFbx do not function similarly under all atrophy models, and that the primary role of MuRF1 may extend beyond controlling protein degradation via the ubiquitin proteasome system.

The α7β1-integrin increases muscle hypertrophy following multiple bouts of eccentric exercise

Mechanical stimuli increase skeletal muscle growth in a mammalian target of rapamycin (mTOR)- and p70(S6K)-dependent manner. It has been proposed that costameric proteins at Z bands may sense and transfer tension to these initiators of protein translation, but few candidates have been identified. The purpose of this study was to determine whether a role exists for the α(7)-integrin in the activation of hypertrophic signaling and growth following eccentric exercise training. Five-week-old, wild-type (WT) and α(7)BX2-integrin transgenic (α(7)Tg) mice were randomly assigned to one of two groups: 1) sedentary (SED), or 2) exercise training (EX). Exercise training consisted of downhill running 3 sessions/wk for 4 wk (-20°, 17 m/min, 30 min). Downhill running was used to induce physiological mechanical strain. Twenty-four hours following the final training session, maximal isometric hindlimb plantar flexor force was measured. Gastrocnemius-soleus complexes were collected for further analysis of signaling changes, which included AKT, mTOR and p70(S6K), and muscle growth. Despite increased p70(S6K) activity in WT/EX, no significant changes in cross-sectional area or force were observed in WT/EX compared with WT/SED. AKT, mTOR, and p70(S6K) activation was higher, and whole muscle hypertrophy, relative muscle weight, myofibrillar protein, and force were significantly elevated in α(7)Tg/EX compared with α(7)Tg/SED. A marked increase in average myofiber cross-sectional area was observed in α(7)Tg/EX compared with all groups. Our findings demonstrate that the α(7)β(1)-integrin sensitizes skeletal muscle to mechanical strain and subsequent growth. Thus the α(7)β(1)-integrin may represent a novel molecular therapy for the treatment of disuse muscle atrophy.

Remodeling in peripheral vein graft revisions: serial study with three-dimensional ultrasound imaging.

Remodeling of vein grafts in the lower limb can lead to stenotic lesions that threaten long-term graft patency. Progressive changes in vein graft geometry were measured at sites of repaired stenoses with three-dimensional (3D) ultrasound imaging. Ten vein graft revisions with patch angioplasty were followed up for 31 to 47 weeks. Four revisions were at valve sites, and six were at sites of diffuse intimal hyperplasia. Sets of spatially registered two-dimensional (2D) cross-sectional ultrasound images were assembled to create 3D computer models of each vein graft. Cross-sectional area measurements in planes normal to the vessel center axis were calculated from the 3D surface reconstructions. Data sets from serial studies were registered in a common coordinate system, and cross-sectional area measurements were compared at matched sites. Three of the four vein graft revisions at valve sites changed by less than 18%, and one decreased in cross-sectional area by 61%. Five of the six revisions at sites of diffuse intimal hyperplasia demonstrated significant decreases in lumen area ranging from 26% to 61%, and one revision exhibited no significant change in cross-sectional area. Reproducibility of the cross-sectional area measurements derived from the 3D imaging technique was 6.9%. Sequential area measurements from 3D ultrasound scans demonstrated different remodeling patterns and rates of change among revision sites within the vein grafts. Lumen narrowing documented with 3D scanning was not associated with consistent flow velocity changes on conventional duplex graft surveillance scans.

Changes in venous lumen size and shape do not affect the accuracy of volume flow measurements in healthy volunteers and patients with primary chronic venous insufficiency

The purpose of this study was the analysis of the rapid changes in the size and shape of the peripheral vein and the associated changes in blood flow velocities and the estimation of their effect on the reliability of the ultrasound scan volume flow (VF) measurements. Ten patients with primary chronic venous insufficiency and 10 healthy volunteers were studied. Two duplex scanners were used simultaneously: one for the velocity measurements in longitudinal plane and another for the cross-sectional area (CSA) measurements in transverse plane during quiet respiration, Valsalva's maneuver (VM), pneumatic cuff compression-decompression, and active dorsiflexion. The patients underwent examination in standing and 15-degrees reverse Trendelenburg's (RT) positions. VF was calculated on the basis of real-time CSA and velocity values. Rapid changes in the CSA as much as 130% for 0.2 seconds were observed. In most cases, the changes in CSA and the flow velocity were inversely related, which resulted in near constant VF. With the exception of VM in the RT position, the difference between real-time VF and mean VF was not significant (P >.05). In the RT position, significant changes in CSA were observed during and immediately after VM. These changes resulted in 23% +/- 15% changes in outflow (both groups) and in 24% +/- 13% changes in reflux (chronic venous insufficiency group). The CSA of the peripheral vein and the flow velocities undergo rapid changes during time intervals of a fraction of a second. The vein can have a noncircular cross-section. To minimize the potential error, VF measurements should be performed during quiet respiration or with cuff compression-decompression. With these conditions, the rapid changes in velocities and CSA do not significantly affect the accuracy of VF measurements because of their inverse relation. CSA should be measured planimetrically, or the site of the measurements should be where the vein is close to a circular shape.

The effect of submaximal eccentric isokinetic training on strength and cross sectional area of the human achilles tendon

This study was designed to investigate the effects of six weeks submaximal eccentric training on concentric and eccentric isokinetic peak torque and cross sectional area (CSA) (muscle and tendon) of calf muscle. Six men and four women volunteered as subjects for this study. Peak torque values for plantar flexion were determined at 30°/s, 60°/s and 90°/s (concentric and eccentric) using a Cybex® Norm before the training, 3 weeks after the beginning and at the end of the sixth week. Following training, peak torque increased in the concentric and eccentric modes in both the trained (p < 0.001) and untrained (p < 0.01) side. No significant change in CSA was noted. The results of this study indicate that after 6 weeks of submaximal eccentric training the strength gained was not completely specific to the contraction type used in training. Transfer of training took place. Neither muscle nor tendon hypertrophy was observed, suggesting the involvement of neural adaptation.

Effects of Unilateral Concentric-Only Dynamic Constant External Resistance Training on Quadriceps Femoris Cross-Sectional Area

ABSTRACT The purposes of this investigation were to determine the effects of unilateral eccentric-only dynamic constant external resistance (DCER) training on the cross-sectional area (CSA) and strength of the trained and contralateral quadriceps femoris muscles. Sixteen young men (age 24.4 ± 3.7 yrs) volunteered to serve as subjects and were divided into a training (Tr) group and a control (Con) group. The Tr group trained the nondominant limb with eccentric-only leg extension DCER exercise 3 times a week for 8 weeks. Pretraining and posttraining CSA and strength measurements for both the trained and contralateral limbs were determined for all subjects using magnetic resonance imaging scans and eccentric DCER strength tests, respectively. The results indicated there was no significant change in CSA of any muscles of the quadriceps femoris of either the trained or contralateral limb. There was, however, a significant increase in the eccentric DCER strength of both the trained (29%) and contralateral (17%) limbs. The strength changes that were unaccompanied by hypertrophy suggest a neural adaptation.

Effects of Unilateral Concentric-Only Dynamic Constant External Resistance Training on Quadriceps Femoris Cross-Sectional Area

ABSTRACT The purposes of this investigation were to determine the effects of unilateral eccentric-only dynamic constant external resistance (DCER) training on the cross-sectional area (CSA) and strength of the trained and contralateral quadriceps femoris muscles. Sixteen young men (age 24.4 ± 3.7 yrs) volunteered to serve as subjects and were divided into a training (Tr) group and a control (Con) group. The Tr group trained the nondominant limb with eccentric-only leg extension DCER exercise 3 times a week for 8 weeks. Pretraining and posttraining CSA and strength measurements for both the trained and contralateral limbs were determined for all subjects using magnetic resonance imaging scans and eccentric DCER strength tests, respectively. The results indicated there was no significant change in CSA of any muscles of the quadriceps femoris of either the trained or contralateral limb. There was, however, a significant increase in the eccentric DCER strength of both the trained (29%) and contralateral (17%) limbs. The strength changes that were unaccompanied by hypertrophy suggest a neural adaptation.

Venous hemodynamic changes during laparoscopic cholecystectomy.

Virchow's triad of venous stasis, vessel wall damage, and hypercoagulability cites three factors that predispose to the formation of venous thrombosis. The pneumoperitoneum created during laparoscopic surgery results in an intraabdominal pressure that exceeds the pressure of venous blood return from the legs. This may alter venous hemodynamics enough to result in venous stasis in the legs, thus increasing the risk of thrombus formation. Duplex ultrasound was used to measure the diameter and venous flow volume of the common femoral vein during laparoscopic cholecystectomy. Measurements were obtained at three different times: after induction of anesthesia but prior to creation of pneumoperitoneum, during pneumoperitoneum, and after abdominal deflation but prior to reversal of anesthesia. After insufflation of the abdomen, the mean cross-sectional area of the common femoral vein increased (0.83 to 1.15 cm2; p = 0.0024) and the venous flow decreased (11.00 to 6.06 cm3/sec; p = 0.0008). After deflation of the abdomen, there was no significant change in cross-sectional area of the common femoral vein, but there was an increase in venous flow (6.06 to 9.94 cm3/sec; p = 0.0005). Abdominal insufflation during laparoscopic cholecystectomy results in dilation of and decreased flow in the common femoral vein. After deflation of the abdomen, flow in the vein returns to baseline levels.

Changes in the bovine teat canal during the nonlactating period and early lactation, as measured by teat canal impressions

Summary Changes in dimensions of impressions of the lumen of the teat canals of 13 cows were examined at 17 intervals during the nonlactating period and early lactation. Impressions were made of teats of 2 diagonally opposed quarters of each cow, using dental impression material. Impression length was measured and cross sections of the impressions at the proximal (distal to Furstenburg rosette), distal (proximal to the teat orifice), and middle (midway between the 2), portions of the teat canal were prepared. Cross sections were photographed and enlarged, and circumference and area were determined by use of planimetry. Effects of making repeated impressions during the nonlactating period and early lactation on new infection rates and somatic cell counts were also assessed. Mean length of teat canal impressions decreased between days 0 and 3 of involution and during the prepartum periods. Depending on the level from which they were taken, cross-sectional areas of impressions tended to increase or increased significantly during the period of involution and again in the prepartum period. Significant changes in cross-sectional area were not observed during early lactation. Changes in circumference of proximal, middle, and distal cross sections followed trends similar to area measurements, but were more variable and differences were less statistically significant. On the basis of our findings, we suggest that heightened susceptibility to new infection during mammary involution and the prepartum period may be attributable, in part, to changes in the patency of the teat canal. Making impressions repeatedly throughout the nonlactating period and early lactation did not affect the number of new intramammary infections.

The role of hemoglobin in arterial narrowing after subarachnoid hemorrhage

A porcine model for subarachnoid hemorrhage has been developed to allow the selective application of blood and its components to cerebral arteries. Whole blood was centrifuged to produce two fractions consisting of washed erythrocytes (red blood cells, RBC's) and white blood cells (WBC) plus platelet-rich plasma (PRP); the RBC fraction was subsequently separated into hemoglobin (Hb)-containing cytosol and erythrocyte membranes. Each fraction was selectively applied to the middle cerebral artery (MCA) of pigs for 10 days; after which, vessels were perfusion-fixed and examined by light and transmission electron microscopy and immunohistochemical studies. By morphometric analysis, a marked reduction in the MCA lumen cross-sectional area was observed after selective application of RBC's or Hb/cytosol but not of WBC/PRP or erythrocyte membranes. In both RBC- and Hb/cytosol-treated vessels, luminal narrowing was associated with a differential increase in vessel wall thickness of the ventral (subarachnoid) compared to the dorsal (brain) aspect of the artery, but no significant change in cross-sectional area of the vessel wall. After 10 days of exposure to RBC's or Hb/cytosol, there was a spectrum of ultrastructural changes in the vessel wall comparable to those seen after periadventitial application of whole blood. Selective application of commercially available Hb to MCA produced similar structural and morphometric changes. The degree of luminal narrowing after exposure to whole blood or RBC's was proportional to the volume of the erythrocyte mass adjacent to the vessel at sacrifice. These data suggest that arterial narrowing after SAH is mediated by mechanisms related to prolonged exposure of the vessel wall to hemoglobin or its catabolites from lysing subarachnoid erythrocytes.