Laminin-α4 Negatively Regulates Adipocyte Beiging Through the Suppression of AMPKα in Male Mice

Laminin-α4 (LAMA4) is an extracellular matrix protein implicated in the regulation of adipocyte differentiation and function. Prior research describes a role for LAMA4 in modulating adipocyte thermogenesis and uncoupling protein-1 (UCP1) expression in white adipose; however, the mechanisms involved are poorly understood. Here, we describe that Lama4 knockout mice (Lama4-/-) exhibit heightened mitochondrial biogenesis and peroxisome proliferator-activated receptor γ coactivator-1 (PGC-1) expression in subcutaneous white adipose tissue (sWAT). Furthermore, the acute silencing of LAMA4 with small interfering RNA in primary murine adipocytes was sufficient to upregulate the expression of thermogenic markers UCP1 and PR domain containing 16 (PRDM16). Silencing also resulted in an upregulation of PGC1-α and adenosine 5'-monophosphate-activated protein kinase (AMPK)-α expression. Subsequently, we show that integrin-linked kinase (ILK) is downregulated in the sWAT of Lama4-/- mice, and its silencing in adipocytes similarly resulted in elevated expression of UCP1 and AMPKα. Last, we demonstrate that treatment of human induced pluripotent stem cell-derived thermogenic adipocytes with LAMA4 (LN411) inhibited the expression of thermogenic markers and AMPKα. Overall, our results indicate that LAMA4 negatively regulates a thermogenic phenotype and pathways involving mitochondrial biogenesis in adipocytes through the suppression of AMPKα.

Laminin-α4 Is Upregulated in Both Human and Murine Models of Obesity

Obesity affects nearly one billion globally and can lead to life-threatening sequelae. Consequently, there is an urgent need for novel therapeutics. We have previously shown that laminin, alpha 4 (Lama4) knockout in mice leads to resistance to adipose tissue accumulation; however, the relationship between LAMA4 and obesity in humans has not been established. In this study we measured laminin-α chain and collagen mRNA expression in the subcutaneous white adipose tissue (sWAT) of mice placed on chow (RCD) or 45% high fat diet (HFD) for 8 weeks, and also in HFD mice then placed on a "weight loss" regimen (8 weeks HFD followed by 6 weeks RCD). To assess extracellular matrix (ECM) components in humans with obesity, laminin subunit alpha mRNA and protein expression was measured in sWAT biopsies of female control subjects (BMI<30) or subjects with obesity undergoing bariatric surgery at the University of Chicago Medical Center (BMI>35) both before and three months after surgery. Lama4 was significantly higher in sWAT of HFD compared to RCD mice at both the RNA and protein level (p<0.001, p<0.05 respectively). sWAT from human subjects with obesity also showed significantly higher LAMA4 mRNA (p<0.01) and LAMA4 protein expression (p<0.05) than controls. Interestingly, even though LAMA4 expression was increased in both humans and murine models of obesity, no significant difference in Lama4 or LAMA4 expression was detected following short-term weight loss in either mouse or human samples, respectively. From these results we propose a significant association between obesity and elevated LAMA4 expression in humans, as well as in mouse models of obesity. Further studies should clarify the mechanisms underlying this association to target LAMA4 effectively as a potential therapy for obesity.

Laminins in metabolic tissues

Laminins are extracellular matrix proteins that reside in the basement membrane and provide structural support in addition to promoting cellular adhesion and migration. Through interactions with cell surface receptors, laminins stimulate intracellular signaling cascades which direct specific survival and differentiation outcomes. In metabolic tissues such as the pancreas, adipose, muscle, and liver, laminin isoforms are expressed in discrete temporal and spatial patterns suggesting that certain isoforms may support the development and function of particular metabolic cell types. This review focuses on the research to date detailing the expression of laminin isoforms, their potential function, as well as known pathways involved in laminin signaling in metabolic tissues. We will also discuss the current biomedical therapies involving laminins in these tissues in addition to prospective applications, with the goal being to encourage future investigation of laminins in the context of metabolic disease.

Laminin-α4 Is Uniquely Upregulated in Subcutaneous White Adipose Tissue in Murine and Human Models of Obesity

As research into the adipocyte microenvironment has advanced, it is becoming more widely accepted that the extracellular matrix (ECM) contributes to adipocyte dysfunction. The majority of current published work focuses on the role of collagens in metabolic disease while less emphasis has been placed on the contribution of laminins, an important component of the adipocyte basement membrane. Laminins are trimeric ECM proteins composed of α, β, and γ chains. The α chains contain sites which can interact with cell surface receptors and is considered the driver of tissue-specific expression and specialized signaling. Our group has shown that the laminin-α4 (LAMA4) chain, which is highly expressed in mature adipocytes, plays a role in adipocyte function and thermogenesis in mice (1). In this study we investigate the relationship between laminin α chain expression and obesity by assessing gene expression of LAMA1-5 in subcutaneous white adipose tissue (sWAT) from mice fed chow (RCD) and 45% high fat diet (HFD) for 8 weeks. Expression of LAMA2 and LAMA4 was significantly increased in the HFD sWAT compared to chow (6.1 fold, p=0.01 and 4.9 fold, p=0.001 respectively), however LAMA4 displayed a much stronger positive correlation with weight (R²=0.697) than did LAMA2 (R²=0.382). In order to validate the relevance of these findings in human models of obesity, we evaluated gene expression of LAMA2, LAMA4, and LAMA5 in sWAT biopsies from non-diabetic adult females with obesity (class II or higher). sWAT samples from obese subjects exhibited 4.5 fold higher LAMA4 expression (p=0.0089) than samples from non-obese control subjects, suggesting that the LAMA4 chain may play an important role in human obesity. Lastly we examined changes in sWAT LAMA4 expression following a period of weight loss in obese mice and in human subjects after bariatric surgery, and found that LAMA4 expression levels remain largely unchanged in both cases. In this study we demonstrate the relationship between LAMA4 expression and obesity and present findings that can be extended to human models of obesity.

Reference: (1) Vaicik et al., Endocrinology. 2018 Jan;159(1):356–67.

Integrins and extracellular matrix proteins modulate adipocyte thermogenic capacity

Obesity and the metabolic disease epidemic has led to an increase in morbidity and mortality. A rise in adipose thermogenic capacity via activation of brown or beige fat is a potential treatment for metabolic diseases. However, an understanding of how local factors control adipocyte fate is limited. Mice with a null mutation in the laminin α4 (LAMA4) gene (KO) exhibit resistance to obesity and enhanced expression of thermogenic fat markers in white adipose tissue (WAT). In this study, changes in WAT extracellular matrix composition in the absence of LAMA4 were evaluated using liquid chromatography/tandem mass spectrometry. KO-mice showed lower levels of collagen 1A1 and 3A1, and integrins α7 (ITA7) and β1 (ITB1). ITA7-ITB1 and collagen 1A1-3A1 protein levels were lower in brown adipose tissue compared to WAT in wild-type mice. Immunohistochemical staining confirmed lower levels and different spatial distribution of ITA7 in KO-WAT. In culture studies, ITA7 and LAMA4 levels decreased following a 12-day differentiation of adipose-derived stem cells into beige fat, and knock-down of ITA7 during differentiation increased beiging. These results demonstrate that extracellular matrix interactions regulate adipocyte thermogenic capacity and that ITA7 plays a role in beige adipose formation. A better understanding of the mechanisms underlying these interactions can be used to improve systemic energy metabolism and glucose homeostasis.

A 3D human adipose tissue model within a microfluidic device

An accurate in vitro model of human adipose tissue could assist in the study of adipocyte function and allow for better tools for screening new therapeutic compounds. Cell culture models on two-dimensional surfaces fall short of mimicking the three-dimensional in vivo adipose environment, while three-dimensional culture models are often unable to support long-term cell culture due, in part, to insufficient mass transport. Microfluidic systems have been explored for adipose tissue models. However, current systems have primarily focused on 2D cultured adipocytes. In this work, a 3D human adipose microtissue was engineered within a microfluidic system. Human adipose-derived stem cells (ADSCs) were used as the cell source for generating differentiated adipocytes. The ADSCs differentiated within the microfluidic system formed a dense lipid-loaded mass with the expression of adipose tissue genetic markers. Engineered adipose tissue showed a decreased adiponectin secretion and increased free fatty acid secretion with increasing shear stress. Adipogenesis markers were downregulated with increasing shear stress. Overall, this microfluidic system enables the on-chip differentiation and development of a functional 3D human adipose microtissue supported by the interstitial flow. This system could potentially serve as a platform for in vitro drug testing for adipose tissue-related diseases.

SMRT Regulates Metabolic Homeostasis and Adipose Tissue Macrophage Phenotypes in Tandem

The Silencing Mediator of Retinoid and Thyroid Hormone Receptors (SMRT) is a nuclear corepressor, regulating the transcriptional activity of many transcription factors critical for metabolic processes. While the importance of the role of SMRT in the adipocyte has been well-established, our comprehensive understanding of its in vivo function in the context of homeostatic maintenance is limited due to contradictory phenotypes yielded by prior generalized knockout mouse models. Multiple such models agree that SMRT deficiency leads to increased adiposity, although the effects of SMRT loss on glucose tolerance and insulin sensitivity have been variable. We therefore generated an adipocyte-specific SMRT knockout (adSMRT-/-) mouse to more clearly define the metabolic contributions of SMRT. In doing so, we found that SMRT deletion in the adipocyte does not cause obesity-even when mice are challenged with a high-fat diet. This suggests that adiposity phenotypes of previously described models were due to effects of SMRT loss beyond the adipocyte. However, an adipocyte-specific SMRT deficiency still led to dramatic effects on systemic glucose tolerance and adipocyte insulin sensitivity, impairing both. This metabolically deleterious outcome was coupled with a surprising immune phenotype, wherein most genes differentially expressed in the adipose tissue of adSMRT-/- mice were upregulated in pro-inflammatory pathways. Flow cytometry and conditioned media experiments demonstrated that secreted factors from knockout adipose tissue strongly informed resident macrophages to develop a pro-inflammatory, MMe (metabolically activated) phenotype. Together, these studies suggest a novel role for SMRT as an integrator of metabolic and inflammatory signals to maintain physiological homeostasis.

APP-Mediated Signaling Prevents Memory Decline in Alzheimer's Disease Mouse Model

Amyloid precursor protein (APP) and its metabolites play key roles in Alzheimer's disease (AD) pathophysiology. Whereas short amyloid-β (Aβ) peptides derived from APP are pathogenic, the APP holoprotein serves multiple purposes in the nervous system through its cell adhesion and receptor-like properties. Our studies focused on the signaling mediated by the APP cytoplasmic tail. We investigated whether sustained APP signaling during brain development might favor neuronal plasticity and memory process through a direct interaction with the heterotrimeric G-protein subunit Gα_S (stimulatory G-protein alpha subunit). Our results reveal that APP possesses autonomous regulatory capacity within its intracellular domain that promotes APP cell surface residence, precludes Aβ production, facilitates axodendritic development, and preserves cellular substrates of memory. Altogether, these events contribute to strengthening cognitive functions and are sufficient to modify the course of AD pathology.

The Absence of Laminin α4 in Male Mice Results in Enhanced Energy Expenditure and Increased Beige Subcutaneous Adipose Tissue

Laminin α4 (LAMA4) is located in the extracellular basement membrane that surrounds each individual adipocyte. Here we show that LAMA4 null (Lama4-/-) mice exhibit significantly higher energy expenditure (EE) relative to wild-type (WT) mice at room temperature and when exposed to a cold challenge, despite similar levels of food intake and locomotor activity. The Lama4-/- mice are resistant to age- and diet-induced obesity. Expression of uncoupling protein 1 is higher in subcutaneous white adipose tissue of Lama4-/- mice relative to WT animals on either a chow diet or a high-fat diet. In contrast, uncoupling protein 1 expression was not increased in brown adipose tissue. Lama4-/- mice exhibit significantly improved insulin sensitivity compared with WT mice, suggesting improved metabolic function. Overall, these data provide critical evidence for a role of the basement membrane in EE, weight gain, and systemic insulin sensitivity.

Loss of presenilin function is associated with a selective gain of APP function

Presenilin 1 (PS1) is an essential γ-secretase component, the enzyme responsible for amyloid precursor protein (APP) intramembraneous cleavage. Mutations in PS1 lead to dominant-inheritance of early-onset familial Alzheimer’s disease (FAD). Although expression of FAD-linked PS1 mutations enhances toxic Aβ production, the importance of other APP metabolites and γ-secretase substrates in the etiology of the disease has not been confirmed. We report that neurons expressing FAD-linked PS1 variants or functionally deficient PS1 exhibit enhanced axodendritic outgrowth due to increased levels of APP intracellular C-terminal fragment (APP-CTF). APP expression is required for exuberant neurite outgrowth and hippocampal axonal sprouting observed in knock-in mice expressing FAD-linked PS1 mutation. APP-CTF accumulation initiates CREB signaling cascade through an association of APP-CTF with Gαs protein. We demonstrate that pathological PS1 loss-of-function impinges on neurite formation through a selective APP gain-of-function that could impact on axodendritic connectivity and contribute to aberrant axonal sprouting observed in AD patients.

DOI:http://dx.doi.org/10.7554/eLife.15645.001

One of the hallmarks of Alzheimer’s disease is the accumulation within the brain of sticky deposits called plaques. These plaques form from clumps of molecules called amyloid-beta peptide. An enzyme called gamma-secretase generates the amyloid-beta peptide, by cutting it from a membrane-associated protein called APP. This enzyme consists of multiple subunits, and a mutation in one of these – presenilin-1 – causes a particularly severe form of Alzheimer’s disease.

For decades, research into Alzheimer’s disease has focused on the harmful effects of amyloid-beta peptides and plaques. However, Deyts et al. now argue that the protein that gives rise to amyloid-beta peptides has a more direct role in Alzheimer’s disease than previously thought. Specifically, APP may contribute to the harmful effects of the presenilin-1 mutations.

By studying genetically modified mice carrying a human presenilin-1 mutation, Deyts et al. show that some of these animals’ nerve cells grow abnormally. Their cell bodies sprout too many branches, while their nerve fibers – which carry electrical signals away from the cell body – become too long. These abnormalities resemble changes seen in the brain in Alzheimer’s disease. Unexpectedly, however, deleting the gene for APP in the presenilin-1 mutant mice prevents the changes from occurring. This suggests that APP must be present for the presenilin-1 mutation to exert this unwanted effect.

An increase in APP-driven signaling within cells seems to trigger the observed abnormalities in nerve cells. The presenilin-1 mutation modifies how gamma-secretase cuts APP at the cell membrane to produce amyloid-beta peptides. This frees up the APP to instead interact with signaling cascades inside the cell. Given that gamma-secretase is a key therapeutic target in Alzheimer’s disease, further work is needed to explore the implications of these protein interactions for potential treatments.

DOI:http://dx.doi.org/10.7554/eLife.15645.002

Breast elastography: A literature review

Breast elastography is a new sonographic imaging technique which provides information on breast lesions in addition to conventional ultrasonography (US) and mammography. Elastography provides a noninvasive evaluation of the stiffness of a lesion. Today, two technical solutions are available for clinical use: strain elastography and shear wave elastography. Initial evaluations of these techniques in clinical trials suggest that they may substantially improve the possibility of differentiating benign from malignant breast lesions thereby limiting recourse to biopsy and considerably reducing the number of benign breast biopsy diagnoses. This article reviews the basics of this technique, how to perform the examination, image interpretation and the results of major clinical studies. Although elastography is easy to perform, training and technical knowledge are required in order to obtain images permitting a correct interpretation. This paper will highlight the technique and point out common pitfalls.

Breast elastography is a new sonographic imaging technique which provides information on breast lesions in addition to conventional ultrasonography (US) and mammography. Elastography provides a noninvasive evaluation of the stiffness of a lesion. Today, two technical solutions are available for clinical use: strain elastography and shear wave elastography. Initial evaluations of these techniques in clinical trials suggest that they may substantially improve the possibility of differentiating benign from malignant breast lesions thereby limiting recourse to biopsy and considerably reducing the number of benign breast biopsy diagnoses. This article reviews the basics of this technique, how to perform the examination, image interpretation and the results of major clinical studies. Although elastography is easy to perform, training and technical knowledge are required in order to obtain images permitting a correct interpretation. This paper will highlight the technique and point out common pitfalls.

A new method to assess the fluidodynamic behaviour of an angiographic contrast agent

PURPOSE

To propose a new method for the assessment of the fluidodynamic behaviour of angiographic contrast agents. The method enables measurement of the spatial distribution and time dependence of the contrast agent along a pseudo-vessel on images obtained with an X-ray image intensifier.

MATERIAL AND METHODS

A particular phantom was devised consisting of a plexiglas box with an insert into which a latex tube with a 0.4 cm in diameter was placed in order to simulate the tortuous flow of a blood vessel. The box, which is filled with water to simulate the thickness of a normal patient, is connected to an injection and pumping system which serve to keep the contrast agent flowing in the pseudo-vessel tube. The pseudo-vessel tube was filled with plain water in one case and with saline solution in another case to assess their different dilution capabilities. The phantom and the flow of contrast agent were imaged with a conventional X-ray image intensifier system and the images were stored in digital format during 35 second acquisitions at a speed of 4 frames per second; for any frame it is possible to measure the mathematical contrast in any position in the image. Further, a diagram showing the time dependence of the spatial distribution of the mathematical contrast is proposed. The X axis shows the spatial distribution of the mathematical contrast, whereas the Y axis shows its temporal variation with a gray level proportional to the mathematical contrast value. By building an horizontal profile of this diagram one can obtain the spatial distribution at a fixed time, while by building a vertical profile one can obtain the temporal variation at a fixed point. Several different contrast agents were so tested.

RESULTS

The proposed method allows different fluido-dynamic behaviour patterns of contrast agents and flowing media to be shown. Owing to the different chemical characteristics of water and saline solution these media have different dilution capabilities (higher for water) and this is well demonstrated by the diagram profiles obtained for each. The system has also allowed the detection of a particular behaviour of some contrast agents, whose spatial distribution was non uniform even in the last frames, thus showing a tendency to maintain their bolus-nature over time. An interesting feature which can be noticed in all the temporal profiles is the presence of a "pre-bolus", i.e. the contrast is higher at the very beginning of the flow, then decreases and after some time starts to increase again. Though the initial contrast value obviously depends on the iodine concentration employed, the method shows the contrast variation as a function of time is different for different contrast agents.

CONCLUSIONS

The method and the equipment proposed provide a good description of the fluidodynamic behaviour of different contrast agents, but do not constitute a reference method for testing haemodynamic behaviour which, "in vivo", is obviously affected by several other chemical and metabolic factors. However, the method allows evaluation of the contrast agents from a physical and fluidodynamic point of view, showing that the iodine content is not the only feature affecting their behaviour. The method can be used in quality control to test the constancy of the physical behaviour of different contrast agents.

[Feasibility of the use of elastographic techniques with ultrasound in the diferentiation of different tissues]

PURPOSE

To investigate the feasibility of distinguishing different tissues by detecting their different elastic properties when mechanically stimulated with an ultrasound wide beam.

MATERIAL AND METHODS

A tissue-mimicking material phantom was placed in a water filled box. Two devices (Teuco Hydrosonic) emitting two US beams (3.2 MHz) were placed on two opposite walls of the box. The US beams had a circular diameter of about 10 cm; their intensity could be set by varying the power voltage applied to the device from 0 to 12 V. The US beams caused a mechanical stimulation of both the phantom and the water surrounding it. An ATL HDI 5000 scanner was used in order to acquire tissue Color Doppler images using the fundamental frequency (Tissue Doppler Imaging, TDI), and the second harmonic (Harmonic Tissue Doppler Imaging, HTDI). The images allowed to visualize, using a color scale, the vibrational status of both the phantom and the water surrounding it. Both fundamental and second harmonic images were taken using different power values supplied to the stimulation device, with the voltage ranging from 0 to 12 V. In order to quantify the vibrational status of the water and of the tissue-mimicking phantom two Regions Of Interest (ROI) were taken on the images. A parameter describing the "color amount" in each ROI and defined by an appropriate mathematical function was proposed.

RESULTS

Differences between the values of the "color amount" parameter in the phantom and in water were statistically significant both at the fundamental frequency and at second harmonic imaging, and for each positive value of the voltage of the power supplied to the device for the stimulation. Also the differences between the parameter "color amount" at the fundamental frequency and second harmonic imaging were statistically significant; the differences were found for both water and phantom and for any positive voltage. The correlation between the intensity of the stimulation (voltage) and the "color amount" parameter is statistically significant with the second harmonic technique in the phantom, nearly significant with the second harmonic technique in water and not significant in the other cases.

CONCLUSIONS

It is possible to try to characterize a tissue by analyzing its elastic properties when an ultrasound wide beam mechanically stimulates it. The most promising technique consists in acquiring images using Harmonic Tissue Doppler Imaging, (HTDI) and measuring the vibrational status by using the "color amount" parameter proposed.

[Study of ultrasonographic image textures with second-order statistical methods]

BACKGROUND

We report the sonographic image texture of the neonatal heart in different stages of development by calculating numerical parameters extracted from the gray scale cooccurrence matrix. To show pixel values differences and enhance texture structure, images were equalized, and then the gray level range was reduced to 16 to allow for sufficiently high occupancy frequency of the cooccurrence matrix.

MATERIALS AND METHODS

We measured B-mode US images, all acquired with the same unit, using the same setup (gain, frequency, constant TGC). For each case measurements were made on 3 diastolic images by selecting a 32 x 64 pixel on the interventricular septum ROI. This procedure was applied to 3 different examinations made at birth, at 3 days, and after a month of life. For each 8 bit image we obtained a coocurrence matrix by sampling adjacent pixels at 0 degree, from which we calculated entropy; then the images were equalized and converted to 4 bit format; on these processed images we calculated 4 gray scale coocurrence matrix samplings adjacent pixels at angles of 0 degree, 45 degrees, 90 degrees, and 180 degrees. Parameters obtained from different angles cooccurrence matrix were averaged to get a numerical parameter independent of sampling angles.

RESULTS

The one-way analysis of variance and Student's "t"-test were performed on the parameters obtained from 3 different examinations and the differences among different developmental stages are 95% significant. No significance was obtained comparing images at birth with those at 3 days.

CONCLUSIONS

Differences are so little significant that they may be due to different factors affecting image texture and the variability introduced by manual ROI positioning; therefore no definitive conclusions can be drawn as to considering this kind of analysis capable of discriminating different stages of myocardial development. To apply this analysis to routine US examinations, different correction factors for range, azimuth, and focal dependence of texture must be considered.

Diagnosis of pelvic masses with transabdominal color Doppler, CA 125 and ultrasonography

BACKGROUND

The objective of this study was to test the accuracy of transabdominal color Doppler imaging in the prediction of malignancy of adnexal tumors when integrated in combination with CA 125 levels and two-dimensional ultrasound.

METHODS

We considered 129 consecutive patients with a suspected adnexal mass at clinical examination and transabdominal and transvaginal two-dimensional ultrasound. Serum CA 125 was measured in all cases. All the patients underwent color Doppler imaging to measure the Resistance index of the tumor associated blood flow profile and then surgery and histologic diagnosis.

RESULTS

The median age of the patients was 44 years (range 12-91), 64.3% were premenopausal and the prevalence of malignancy was 28.7%. The sensitivity of color Doppler mapping was 75.7%, specificity 71.7%, positive predictive value 68.3% and negative predictive value 93.0%, compared with 75.7%, 68.5%, 49.1% and 87.5% for CA 125 and 83.8%, 83.7%, 67.4% and 92.8% for two-dimensional ultrasound. Blood flow was undetectable by color Doppler imaging in 17 of the 129 cases (13.2%). In 55 patients with three concordant tests, the positive and negative predictive values were 100%. When CA 125 values and two dimensional ultrasound results were discordant (35 patients), the color Doppler diagnosis was correct in 88.6% of the cases (93% in premenopausal women).

CONCLUSION

Color Doppler imaging alone is not better than two-dimensional ultrasound in predicting malignancy of pelvic masses. Its use together with CA 125 and two-dimensional ultrasound may improve the accuracy of predictions when the three tests are concordant or when the other two are discordant.

Percutaneous cervical diskectomy: preliminary experience

We assessed the feasibility of percutaneous treatment of a cervical herniated disc. In the lumbar region, the surgical instrument for percutaneous diskectomy passes only through the paravertebral muscles, while in the cervical region there is considerable risk of nervous, parenchymal and vascular lesions. Moreover, open surgery for cervical herniated nucleus pulposus is a well-established, low-risk procedure, with little risk of epidural fibrosis, the main complication of lumbar open surgery; a percutaneous procedure should therefore have a low morbidity rate. A safe percutaneous approach to cervical discs could be useful for biopsy and for treatment of high-risk patients for general anaesthesia. We treated 15 patients with cervical herniated nucleus pulposus; all gave informed consent and refused or were not eligible for open surgery. We used the Nucleotome described for treatment of lumbar herniated discs; except for the first three cases, we used colour Doppler sonography to detect hazardous structures in the path of the probe. We had one complication, a cervical haematoma due to damage to the inferior thyroid artery, prior to the use of ultrasound.

[Color Doppler ultrasonography versus angiography in leg aneurysms]

The authors compared color-Doppler US with angiographic findings in the study of peripheral lower limbs aneurysms. Twelve cases were observed over a 2-year period of time. In each case, the combination of B-mode and color-Doppler US permitted the accurate evaluation of the aneurysm and of the possible compression of adjacent vessels. Angiography, which was considered the gold standard, detected only 8 of 12 cases; in 3 of 8 cases, the actual diameter of the aneurysm was under estimated. The simultaneous visualization of vessel wall and of intraluminal blood flow proved color-Doppler US to be superior to the gold standard in these cases. The authors conclude that color-Doppler US may become the new reference standard in the diagnosis and follow-up of peripheral aneurysms.

Percutaneous Sclerotherapy of Varicocele: Personal Experience

The Authors describe their experience regarding 80 cases of selective phlebography of the spermatic vein in men with varicocele. Percutaneous transvenous retrograde sclerotherapy of the internal spermatic vein was performed in 78 patients (type 1 and type 3 according to Coolsaet). Follow-up colour-doppler 1 month after sclerotherapy revealed a persistent varicocele in only 3% of cases. The Authors present the advantages of percutaneous sclerotherapy.

[Role of echography in the diagnosis of ovarian tumors]

The role of sonography is evaluated in the diagnosis of ovarian tumors. Real-time US proves more sensitive than gynecological examination in the diagnosis of ovarian diseases. As yet, however, no correlation has been found between histological findings and US appearance. An accurate review of the relative literature and of our results lead us to the conclusion that sonography does not significantly affect the early diagnosis of ovarian tumors.

[Differential diagnosis of hematoma, pulsating hematoma and pseudoaneurysm of the femoral artery using color Doppler]

Color Doppler and Duplex Doppler US were employed on 4 patients with clinically suspected pseudoaneurysms as a complication of femoral artery puncture after cardiac catheterization. Pseudoaneurysms were identified with Color Doppler US and their typical appearance was confirmed. The grey-scale findings did not allow an adequate differentiation between hematoma and pulsed hematoma without fibrous encapsulation: only Color Doppler US easily detected the track between damaged artery and blood collection and allowed a sample to be obtained for pulsed Doppler examination. Color Doppler US allowed an accurate and non-invasive diagnosis of groin masses after femoral artery catheterization.

[Echo-guided renal biopsy in patients with a medical nephropathy]

Ninety-five percutaneous renal biopsies under ultrasound guidance were performed on 89 patients with nephrologic diseases. Accurate diagnosis was reached in 93% of cases at the first biopsy, and the figure increased to 100% after a second biopsy. The use of 18 and 16 gauge needles allowed correct histological diagnosis in 95% of patients, and satisfactory histology in the extant 5%. US guidance and the use of 18 and 16 gauge needles reduced the complications related to renal biopsy: in fact, severe hematuria occurred in 2 cases only.

Transcatheter embolization of hypogastric arteries as an aid or alternative to surgery in the management of life-threatening pelvic haemorrhage

Transcatheter embolization for uncontrollable haemorrhage from pelvic organs was performed in 27 patients (12 women, 15 men) as an aid or alternative to surgery. The advantages and peculiarities of different embolic materials employed, and methods for managing intractable haemorrhage are discussed.