MR pyelography in 115 patients with a dilated renal collecting system

Purpose: To evaluate the accuracy of MR pyelography in the assessment of hydroureteronephrosis.

Material and Methods: One hundred and fifteen patients, with variable degree of hydroureteronephrosis demonstrated by US and urography were subjected to MR pyelography obtained by means of two ultra-fast sequences.

Results: Of the 228 kidneys examined, the collecting systems of 130 kidneys were dilated and correctly identified on MR pyelography, with only 2 false-positive results. The specificity of MR pyelography in detecting hydronephrosis was 98%. Accuracy in revealing level of obstruction was 100%. Sensitivity in detecting stones, strictures and congenital ureteropelvic junction obstructions was respectively 68.9%, 98.5% and 100%.

Conclusion: MR pyelography can rapidly and accurately depict the morphological features of dilated urinary tracts with information regarding the degree and level of obstruction, without using contrast medium or ionizing radiation.

HIGH-MOBILITY GROUP BOX 1 IN ALLERGIC AND NON ALLERGIC UPPER AIRWAY INFLAMMATION

High mobility group box 1, an evolutionary ancient protein conserved in the eukaryotic kingdom, exerts intra- and extra- cellular functions, orchestrating a homeostatic defensive response in challenged tissues. Its action associated with various inflammatory cells is essential for the occurrence, progression, and persistence of asthma, rhinitis, and nasal polyposis. The recent discovery of High mobility group box 1, as a critical mediator of inflammation, stimulated an increasing interest in the field of inflammation research, suggesting new therapies for atopic and non-atopic inflammatory processes.

Proton magnetic resonance spectroscopy (H-MRS) in chronic schizophrenia. A single-voxel study in three regions involved in a pathogenetic theory

The cognitive dysmetria theory suggests a disconnectivity between the dorsolateral prefrontal cortex, thalami and vermis to explain the pathophysiology of schizophrenia. This study investigated the metabolic integrity of this neurologic circuit in patients with schizophrenia using proton magnetic resonance spectroscopy (H-MRS). Twenty-two patients with schizophrenia and twelve control subjects were studied. Metabolites concentrations were evaluated by a single-voxel technique in the prefrontal cortex, thalami and vermis. To our knowledge, this is the first H-MRS experience with concomitant evaluation of these regions in schizophrenic patients. We found no significant statistical difference in N-AA, Cho and Cr absolute concentrations and N-AA/Cho, N-AA/Cr and Cho/Cr ratios between the schizophrenic patients and control group. At the vermis, we found a constant spectrum with low levels of N-AA and higher levels of Cho and Cr. Our experience does not clearly support or refute the cognitive dysmetria theory. The consistency of metabolic findings in the cerebellar vermis could represent an important datum, highlighting the specificity of metabolic and functional activity in this region.

Arteriovenous fistula of the mandible simulating an odontogenic cyst. A case report

SUMMARY

We describe a rare case of mandibular highflow arteriovenous malformation (AVM) mimicking an odontogenic cyst in a young man. The diagnosis of mandibular AVM was made by CT angiography and confirmed by digital subtraction angiography. CT scan showed the extent of mandibular bone alteration and a double enlarged mandibular canal on the same side. An AVM containing a large aneurysm was demonstrated by CT angiography.The mandibular AVM was successfully treated by endovascular therapy with Guglielmi detachable coils. On panoramic radiogram, mandibular AVMs can appear as cystic lesions without pathognomonic features. Several benign and malignant tumours of this anatomical region must be considered in the differential diagnosis.We emphasize the radiological sign of double enlarged mandibular canal and the diagnostic role of CT, particularly CT angiography, to discriminate a mandibular AVM from neoplastic entities of this region, sparing the risks of a needle biopsy.

SDH Mutations in Patients Affected by Paraganglioma Syndromes: A Personal Experience

Mutations in genes encoding mitochondrial succinate dehydrogenase (SDH) are frequently involved in the development of neural crest-derived (NCD) tumors, such as pheochromocytomas (PHEOs) or paragangliomas (PGLs). In this study we report the results of sequencing analysis in leukocyte DNA of patients affected by PHEO/PGL who turned out to be SDH mutation carriers. A nonsense germline heterozygous mutation (Q109X) was found in the exon 4 of the SDHD gene in the index cases of six unrelated families affected by PHEO/PGL. Haplotype analysis showed the presence of a founder effect. Affected patients showed high clinical variability, ranging from monolateral to bilateral glomus tumors, variably associated or not with PGLs or PHEOs. A novel missense SDHD variant, T112I, was also found in one of our families. A new missense G106D mutation, involving a highly conserved amino acid, was found in two sisters affected by bilateral glomus tumors. A P81L mutation associated with abdominal and head and neck PGL was detected in three families. A G12S variant of the SDHD gene was found in one patient affected by a PHEO. The finding of this variant in 3 of 100 control subjects suggests that it is a polymorphism and not a mutation. A novel IVS2-1G>T variant was found at intron 2 of SDHD gene in one patient affected by a glomus tumor. All the tumors associated with SDHD mutations were benign. Conversely, the only mutation we found in SDHB gene (IVS3+1G>A) was associated with a malignant PHEO.

Role of coronal oblique reconstruction as a complement to CT study of the temporal bone: normal anatomy

PURPOSE

The purpose of this study was to demonstrate the usefulness of coronal oblique multiplanar reconstruction computed tomography (MPR CT) reformation parallel to the basal turn of the cochlea in the evaluation of the retrotympanum and hypotympanum to complete the standard CT examination of the temporal bone obtained with axial and coronal images.

MATERIALS AND METHODS

We studied 30 patients aged 18-79 years for a total of 60 normal petrous pyramids. All examinations were performed on a multislice CT (MSCT) scanner (Sensation 16, Siemens, Erlangen, Germany) with axial volumetric acquisition and completed with reformations of coronal and coronal-oblique images. MSCT scan parameters for axial acquisition were set as follows: 0.75-mm scan collimation, FOV 300 mm, 170 mAs. Axial images were reconstructed at 0.7-mm thickness and with a reconstruction increment of 0.5 mm using a high-resolution bone algorithm.

RESULTS

Coronal oblique MPR CT reformations provided additional information with respect to standard CT images in all cases. In particular, they enabled measurement of the craniocaudal and laterolateral diameters of the sinus tympani. In all cases, there was optimal visualisation of the ponticulus and subiculum. Analysis of the pyramidal eminence was improved thanks to its visualisation in profile. Moreover, we obtained an optimal representation of the hypotympanum, which was always exhaustively explored with only one reconstruction. Finally, in all cases, it was possible to identify the facial nerve canal and main vascular structures and to measure the distance between these and the sinus tympani, pyramidal eminence and hypotympanum. The coronal oblique CT reformation was of no advantage in the evaluation of the fossa of the oval window and the niche of the round window.

CONCLUSIONS

Coronal oblique MPR CT reformation should not be considered an alternative to the standard CT examination, but it can represent a valid integration to provide additional information on particularly crucial districts characterised by frequent involvement of inflammatory and/or expansile disease and because of their difficult endoscopic approach. Moreover, it can represent a meaningful aid to optimise surgical planning thanks to its different perspectives of observation.

Cerebral angiography in the rat with mammographic equipment: a simple, cost-effective method for assessing vasospasm in experimental subarachnoid haemorrhage

We report quantification of vasospasm following subarachnoid haemorrhage (SAH) and the effect of a new antivasospastic free radical scavenger (AVS) in rats, using an angiographic technique developed in our laboratory. We acquired single-exposure angiograms with mammographic equipment, using a 0.1 mm diameter focal spot and single-emulsion mammographic films. Contrast medium was injected through a PE50 catheter in the common carotid artery, after the external carotid artery had been ligated to divert flow towards the internal carotid artery territory. Measurements of the M1 and A1 segments and of the middle third of the basilar artery were made by projecting the angiograms directly as slides and using the endovascular catheter as an internal reference. We tested the technique on 40 male albino Sprague-Dawley rats divided into four groups: sham-operated+saline, SAH+saline, sham-operated+AVS and SAH+AVS. We were able to measure the diameter of the principal intracranial arteries in all the animals. With our technique, which is cost-effective when compared to many of those reported recently, we could detect intracranial vasospasm in all untreated rats with SAH, and confirm antivasospastic effects of AVS.

Ossifying lipoma of the parapharyngeal space: CT and MRI findings

Ossifying lipomas independent of bone tissue are very rare. A literature review revealed that only few cases of ossifying lipoma independent of bone tissue have been reported. None of the cases have been reported in the international radiology literature. In addition, there are no reports concerning the MRI features of this entity. We describe CT and MRI findings in a case of ossifying lipoma of the parapharyngeal space.

MR white lung sign: incidence and significance in pulmonary consolidations

PURPOSE

The presence of a pulmonary consolidation with a signal intensity comparable with that of the static fluid on heavily T2-weighted MR images has been named the "MR white lung sign." This sign has been described in mucinous bronchioloalveolar carcinoma (BAC). Our purpose was to establish the frequency and significance of this sign in pulmonary consolidations of varied causes.

METHOD

In this prospective study, 83 patients with pulmonary consolidation underwent MR examination between January and December 1999. Segmental or lobar consolidations were due to pneumonia without central obstruction (n = 22), pneumonitis with central obstruction (n = 21), cicatricial atelectasis (n = 8), passive atelectasis (n = 10), radiation pneumonitis (n = 8), mucinous BAC (n = 5), infarction (n = 3), bronchiolitis obliterans organizing pneumonia (n = 3), nonmucinous BAC (n = 2), and lymphoma (n = 1). The MR white lung sign was considered present when the signal intensity of a pulmonary consolidation was comparable with that of the static fluid on heavily T2-weighted images obtained with MR hydrography sequences. Interobserver agreement, sensitivity, and specificity of the white lung sign in diagnosing mucinous BAC were calculated.

RESULTS

The MR white lung sign was present in 7 (8%) of 83 consolidations, including 5 (100%) of 5 cases of mucinous BAC and 2 (10%) of 21 cases of obstructive pneumonitis. The frequency of the white lung sign was 100% in mucinous BAC and 2.6% in consolidations due to other causes. The difference was statistically significant (p < 0.05).

CONCLUSION

The white lung sign is an uncommon finding in pulmonary consolidations evaluated with heavily T2-weighted sequences. However, the sign is characteristic of mucinous BAC and adds specificity to the radiologic diagnosis.

Perineural spread in a case of sinonasal sarcoidosis: case report

We report a case of sinonasal sarcoidosis with perineural spread along the trigeminal and vidian nerves in which primarily MR imaging but also CT allowed excellent visualization of this infiltration.

Gallbladder duplication: MR cholangiography demonstration

Gallbladder duplication is a rare anatomic malformation. We present a case of gallbladder duplication in a patient who underwent laparoscopic cholecystectomy in which breath-hold magnetic resonance cholangiography showed the biliary anomaly, allowing a correct preoperative differentiation of the specific type of duplication.

Norepinephrine reuptake is impaired in skeletal muscle of hypertensive rats in vivo

Certain forms of experimental hypertension are characterized by organ-specific alterations of catecholaminergic pathways. The purpose of this study was to evaluate, in the same awake and freely moving normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) before and after the development of arterial hypertension, the norepinephrine (NE) turnover and, in particular, the neuronal NE reuptake activity that ends its effects once released from nerve terminals, in subcutaneous adipose tissue and in skeletal muscle, whose sympathetic efferents are respectively independent or dependent from baroreflexes. Plasma and tissue interstitial NE and 3,4-dihydroxyphenylethylene glycol (DHPG), its major deaminated metabolite, were measured before and after blockade of NE reuptake by tissue perfusion of desipramine through microdialysis probes. Arterial pressure and plasma NE in SHR were similar to those in WKY at 5 weeks of age but increased at 16 weeks of age. In contrast, plasma DHPG was already higher in young SHR. Basal interstitial NE and DHPG were increased in both tissues of young and old SHR compared with age-matched WKY. Desipramine induced a higher rise of interstitial NE in SHR of both ages, with a lesser increase in the skeletal muscle of old compared with young SHR. These results indicate an increased NE turnover in prehypertensive and hypertensive SHR in both baroreflex-dependent and -independent tissues, not shown by plasma NE levels in young SHR. In the skeletal muscle, where sympathetic efferents are baroreflex dependent, the reduced interstitial NE reuptake contributes to the higher availability of interstitial NE for postsynaptic effects in old SHR.

[Doppler power with contrast media in the characterization of renal masses]

PURPOSE

To report the results of a prospective study investigating the potentials of contrast-enhanced power Doppler in the diagnosis of expansive renal lesions.

MATERIAL AND METHODS

From 1997 to October 30, 1999, we studied 59 expansive renal lesions (28 malignant, 31 benign) in 48 patients (mean age 55 years, range 10-79) with power Doppler US before and after the administration of an echo-enhancing agent (Levovist, Schering AG, Berlin, Germany). We identified 5 patterns of vascular architecture of the lesions, both before and after contrast agent administration, following the classification by Jinzaki e Coll.

RESULTS AND DISCUSSION

Power Doppler US showed vascular structures in 34 patients. The administration of Levovist revealed vessels in 12/25 lesions which had none at baseline studies and in 6 cases vascularity was particularly evident. Color signals were enhanced in all the 34 vascularized lesions, which allowed better definition of vascular patterns. The characterization of vascular patterns with baseline power Doppler US helped improve diagnostic accuracy compared to gray-scale US (58% versus 32%) for hyperechoic lesions, complex cysts and pseudomasses. Independent of contrast agent administration, the integration of gray-scale and power Doppler modes increased diagnostic accuracy even further (76% correct diagnoses).

CONCLUSIONS

In our series, the US contrast agent did not increase the diagnostic accuracy of power Doppler in the differential diagnosis of hyperechoic renal lesions; conversely, Levovist can be advantageous for the characterization of suspected pseudomasses and complex cysts.

Magnetic resonance imaging of bronchioloalveolar carcinoma

The purpose of this study is to describe the magnetic resonance (MR) features of bronchioloalveolar carcinoma. MR examinations of 18 patients with proven bronchioloalveolar carcinoma were reviewed. Detection at computed tomography (CT) and pathologic confirmation were the entry criteria. Nine patients had a solitary nodule, three patients a lobar consolidation, and six patients had diffuse disease. For each patient, both breath-hold T2-weighted fast spin-echo, and breath-hold T1-weighted gradient-echo images, before and after injection of gadolinium, were available. Nine patients with pulmonary consolidation or diffuse disease had also heavily T2-weighted MR imaging (Haste or TSE 240; Siemens, Erlangen, Germany). MR imaging showed pulmonary abnormalities in 17 of 18 patients. Unenhanced T1-weighted and T2-weighted images depicted tumor in 16 of 18 patients. Contrast-enhanced T1-weighted images showed tumor in 17 of 18 patients. In no case did MR imaging depict abnormalities corresponding to the ground-glass opacities seen on CT scans. In three patients with mucinous bronchioloalveolar carcinoma, heavily T2-weighted images showed lesions isointense with respect to static fluid of the human body. In conclusion, the ability of MR imaging in detecting small nodules and ground-glass opacities is limited. However, heavily T2-weighted sequences are able to show the presence of mucin. This is useful information because mucinous bronchioloalveolar carcinoma carries a poor prognosis.

Hypertension as an etiopathological factor in the development of cerebral atrophy in hemodialyzed patients

Twenty-five patients on long-term regular hemodialysis treatment (RDT) at our dialysis unit who underwent diagnostic cerebral computed tomography (CCT) participated in a study aimed at clarifying the pathogenesis of cerebral atrophy occasionally found at their original scan. The upper age limit was 55 years to exclude the physiological involutive brain changes occurring with age. Cerebral atrophy (CA), as defined morphologically (enlargement of cerebral sulci or an increased Evan's Index), was detected in all cases. Seventeen patients underwent magnetic resonance imaging (MRI) to define possible white matter changes more accurately. No significant correlation was found between the degree of atrophy and the following uremia-altered hematoseric parameters: creatinine, hematocrit, cholesterol, triglyceridemia, albumin, PTH, calcium, inorganic phosphate. There was no correlation between degree of atrophy and number of months the patients had been on RDT or time that passed between the finding of a creatinine clearance <30 ml/min and the start of RDT. Very high correlations were found between the degree of CA and predialytic blood pressure values, and between CA and the duration of hypertension (n = 13, r = 0.66, p < 0.013). Thus, hypertension seems to be an early cause of cerebral parenchymal damage in RDT patients, and should be promptly corrected.

Regional sympathetic activity in pre-hypertensive phase of spontaneously hypertensive rats

Imbalances in central and peripheral sympathetic nervous system (SNS) activity have been observed in essential and experimental hypertension. This study was carried out in order to evaluate SNS activity in two distinct tissue types of spontaneously hypertensive rats (SHR), compared to Wistar-Kyoto normotensive (WKY) rats, in the pre-hypertensive phase (4-5 weeks of age). Interstitial concentrations of norepinephrine (NE) and other catecholamines were measured by microdialysis in striated muscle, whose tone is controlled by baroreflexes, and in the subcutaneous adipose tissue where sympathetic output mainly controls metabolism. Two groups of SHR and WKY male rats were studied, aged 4-5 weeks, with a mean body weight of 92 and 86 g respectively. Systolic blood pressure (SBP, tail-cuff) values were 113 mm Hg (SD +/- 6.2) in SHR and 108 mm Hg (SD +/- 7.3) in WKY rats (p=0.28,t test). Two microdialysis probes were positioned in the subcutaneous fatty tissue and in the striated muscle of the parascapular region and perfused with Ringers' solution. The dialysate was collected every thirty minutes for 3 hours and analyzed in HPLC-ED to determine the content of NE and other catecholamines. Interstitial levels of NE were higher in SH than in WKY rats in both tissues. Mean NE values from subcutaneous adipose tissue in 4-5 week-old SHR were 1162 +/- 193 pg/ml compared to 496 + 188 pg/ml in WKY rats (p<0.001, t test). Muscle tissue NE levels in SHR were 1241 +/- 337 pg/ml vs. 521 +/- 138 pg/ml in WKY rats (p<0.001, t test). Plasma NE concentrations (279 +/- 61 pg/ml in SHR vs 246 + 69 pg/ml in WKY P = 0.65, t test) were not significantly different between the two strains at this young age. These findings suggest SNS hyperactivity in young SHR, though still normotensive, possibly dissociated from regional components of regulation (baroreceptor control in striated muscle and metabolic control in subcutaneous adipose tissue).

Effects of reduced preload on diastolic filling in essential hypertensive patients with increased left ventricular mass

Doppler-derived indices of diastolic filling are widely used in the routine evaluation of essential hypertensives. However, these indices are affected by loading conditions and systolic performance. This study aimed at monitoring the transmitral flow pattern and indices of left ventricular systolic function during acute nonpharmacological isolated reduction of preload in essential hypertensives with left ventricular hypertrophy. Nine essential hypertensive patients with left ventricular hypertrophy and nine age- and sex-matched normotensive controls underwent echocardiographic and Doppler evaluation of both systolic function and diastolic filling indices at baseline and during lower body suction at -40 mm Hg. Lower body suction caused a similar decrease in end-diastolic volume index, stroke volume index, and midwall fractional shortening in the normotensives and hypertensives. Circumferential end-systolic stress was unaffected in both groups. Acceleration time of early diastolic filling and isovolumic relaxation time increased in the normotensives but not in the hypertensives. Deceleration time of early diastolic filling increased in both groups. The ratio of peak velocities during early filling and at atrial contraction decreased in the normotensives, whereas it was unchanged in the hypertensives; this was due to the fact that early filling velocity decreased in both groups, whereas peak velocity at atrial contraction decreased only in the hypertensives. We conclude that Doppler-derived diastolic filling indices are not affected by a reduction of preload in essential hypertensives with left ventricular hypertrophy.

[The relationship between regional sympathetic activity and the onset of arterial hypertension in spontaneously hypertensive rats]

Several studies on spontaneously hypertensive rats (SHR) have demonstrated increased activity of the sympathetic nervous system (SNS). Using microdialysis, we have observed a greater release of norepinephrine (NE) into the interstitia of striated muscle, than that observed in control Wistar-Kyoto (WKY) rats in the prehypertensive phase. We confirmed these results in the subcutaneous adipose tissue where the sympathetic output controls metabolism. This study was carried out in order to evaluate SNS activity in two district tissue types conducted during both the prehypertensive phase (4-5 weeks of age) and the established hypertensive phase (15-16 weeks of age). Interstitial concentrations of NE were measured by microdialysis in striated muscle and subcutaneous adipose tissue. Two groups of rats were studied. Each group was made up of 8 subjects, SHR and WKY, males of 4-5 weeks of age with a mean body weight of 80 and 75 g respectively. Arterial systolic pressure (tail-cuff) values were 106 mmHg (standard deviation +/-8.2) in SHR and 101 mmHg (standard deviation +/-6.9) in WKY rats (NS). Two microdialysis probes were positioned in the subcutaneous fatty tissue and in the striated muscle of the parascapular region and perfused with Ringers' solution. The dialysate was collected every 30 min for 150 min and analyzed in high-performance liquid chromatography-every day. The content of NE and other catecholamines was determined. The same animals in both groups were reevaluated at 15-16 weeks of age. The mean body weight at this time was 246 g for the SHR and 289 g for the WKY rats. Arterial systolic pressure was 161 mmHg (standard deviation +/-13.3) and 108 mmHg (standard deviation +/-15.6) respectively (p < 0.01, Student's t test). Interstitial levels of NE were higher in SHR than in WKY rats in both tissues examined in the prehypertensive phase and in the established hypertensive phase. Mean NE values from subcutaneous adipose tissue in 4-5 week-old SHR were 1362.1 +/- 181.3 pg/ml compared to 479.0 +/- 162.3 pg/ml in WKY rats (p < 0.001, Student's t test). Muscle tissue NE levels in SHR were 1292.7 +/- 319.1 vs 536.3 +/- 146.7 pg/ml in WKY rats (p < 0.001, Student's t test). Values from the same rats at 15-16 weeks of age were 1405.0 +/- 148.3 pg/ml in SHR compared to 501.6 +/- 131.2 pg/ml in fatty tissue from WKY rats and 1893.7 +/- 214.6 vs 502.0 +/- 118.8 pg/ml in muscle tissue from the respective groups (p < 0.001, Student's t test). Significant differences (p < 0.01, Student's t test) were also observed in mean NE values in striated muscle tissue during the developing phase of hypertension. These findings document SNS hyperactivity in SHR when compared to WKY normotensive controls. This increase in SNS activity was observed in both the prehypertensive phase and in the established hypertensive phase indicating a complete disassociation from regional components of regulation (baroreceptor control and metabolic control), at least in the prehypertensive phase. These results may suggest as alteration in primitive sympathetic central outflow. Higher interstitial NE concentrations in the muscle tissue from SHR during the hypertensive phase compared to levels of young animals that are still normotensive, reveal an interesting pathophysiological aspect for the development of arterial hypertension.

Therapeutic infiltration of the facet joint in minor intervertebral disease

SUMMARY

A CT-guided infiltration technique of the facet joints was employed on a group of 20 patients suffering from sciatica without any signs ofmorphostructural alteration of the facet joints, secondary to Minor Intervertebral Disease (MID). The typical flouroscopically guided intra-articular facet arthrography has been substituted by a CT-guided technique that privileges therapy rather than diagnosis. The study involved 20 patients between 29 and 57 years of age (average 44.5), of both sexes (16 females and four males). The average time which elapsed from onset of symptomatology was 9.5 months. At seven days after the first treatment subjective results were considered excellent by 11 patients (55%), good by one (5%) and satisfactory by one (5%). Six out of20 patients (30%) failed to gain any relief of symptoms. Only one patient (5%) had a worsening of pain. Clinical evaluation by the physician at the same time showed a good result in 11 patients (55%), satisfactory in two (10%). In six patients (30%) the symptomatology was unchanged. At 4 months the subjective results were excellent in three (15%), good in six (30%) and satisfactory in two (10%) . Nine (45%) had no positive results. The clinical examination was excellent in tWo (10%), good in seven (35%), satisfactory in two (10%) and without any relief of symptomatology in nine (45%). These results encourage the use of CT-guided infiltration that, together with the small amount of contrast medium injected into the joint space, make it a safe technique for patients, avoiding or reducing complications.

Progression of cerebral atrophy in patients on regular hemodialysis treatment: long-term follow-up with cerebral computed tomography

Fifteen patients (10 males, 5 females) on regular hemodialysis treatment (average age 43.6 +/- 4.0 years, average time on dialysis 100.7 +/- 62.8 months) underwent cerebral computed tomography between 1981 and 1984. Ten patients showed mild cerebral atrophy (CA) on the basis of cortical sulci exceeding 3 mm in breadth and an Evans ratio exceeding 0.31, for a total of 14 degrees of CA (mean 0.9 +/- 1). The same 15 patients underwent a second cerebral computed tomography during 1991/92 (101 +/- 23.7 months later). At that time, the patients exhibited a degree of CA of 2.6 +/- 1.4, for a total of 39 degrees with an overall increase of 25 degrees. Since CA is not detected before the age of 55 years in the normal population, we conclude that the CA in this patient group can only be attributed to uremia-related pathology and that it tends to worsen as regular hemodialysis treatment continues. Nevertheless, no evident cognitive, affective, or behavioural changes were verified in these patients. To our knowledge, this is the first presentation of radiologically documented progression of CA in the same patient population over time.

Treatment of biguanide-induced lactic acidosis: reproposal of the "physiological" approach and review of the literature

We report a case of severe biguanide-induced lactic acidosis which did not respond to symptomatic alkali treatment via either intravenous bicarbonate infusion or bicarbonate-dialysis. We thus initiated a therapeutic strategy based on insulin and thiamine only in order to reactivate the pyruvate oxidative pathway, in which both drugs play important roles as cofactors. This original "physiological" approach proved effective, and further alkali administration was unnecessary. Our results prompted a review of the literature on the treatment of biguanide-induced lactic acidosis, a situation in which the absence of precise therapeutic rules can undoubtedly affect both the evolution and the prognosis of the syndrome.

[The treatment of arterial hypertension in diabetes mellitus. Choices and problems]

Recent studies indicate that arterial hypertension in diabetes mellitus is a paramount pathogenetic step in the evolution and acceleration of diabetic macro- and microangiopathy and in particular in the development of nephropathy and uremia. This paper deals with the clinical problems of antihypertensive treatment in diabetic patients and discusses the antihypertensive repertory with the aim at determining the best drug choice in the individual case. In the light of our present pathophysiologic knowledges of the intrarenal effects of the various classes of antihypertensive drugs the possibility of preventing diabetic nephropathy is discussed.

[The pathogenesis of arterial hypertension in diabetes mellitus and its role in nephropathy]

This paper synthesizes the pathogenic steps of arterial hypertension in diabetes mellitus: hyperosmolarity due to the hyperglycemia and increased sodic tubular reabsorption accounting for the expansion of the extracellular volume with hypervolemia; abnormalities of the ionic membrane pumps leading to abnormal intracellular calcium distribution, thereby inducing an increased vascular tone; atypical vasomotor reactivity to cathecolamines; modifications of the renin-angiotension-aldosterone system. The pathophysiological derangements by which hypertension could induce nephropathy are examined: the vasodilatation which can be detected from the onset of diabetes, may be a determinant in the transmission of systemic hypertension to the glomerular microcirculation with resulting enhancement of the hydrostatic transglomerular pressure gradient (i.c. the major factor producing glomerular injury), glomerular plasmatic flow and filtration rate. The nephron hyperfiltration increases the movement of plasmatic proteins across the glomerular capillary wall with subsequent mesangial hyperactivity and sclerosis. Antihypertensive treatment in diabetes follows general guidelines and it should be instituted even in the case of microhypertension being facilitated in this setting the appearance of microalbuminuria i.e. the starting point of nephropathy. Even if experimental studies are to favor ACE inhibitors as the first-line drugs for abating glomerular hypertension by mitigation of the direct effect of angiotensin II on the efferent arteriolar tone, clinical observations suggest that, regardless of type of treatment, the normalization of systemic arterial pressure, by reversing glomerular hypertension may be effective in preventing diabetic nephropathy.

[Current approach in the prevention and treatment of diabetic nephropathy]

Diabetic renal microangiopathy accounts for enormous morbidity and mortality, particularly in patients who develop diabetes in childhood or early youth; in the last few years its pathogenesis has been therefore extensively studied, aiming to prevent renal complications or at least of slowing down its progression toward uremia. Though not always in accordance with theoretical expectations, the results of clinical trials have nevertheless widened our therapeutic possibilities; in fact, besides the attainment of an optimal metabolic control, other possible interventions include a careful correction of albeit minimal elevations in arterial pressure; the interference with intrarenal hemodynamic parameters; the correction of insulin-independent metabolic pathways, abnormally activated in the diabetic, such as non enzymatic glycation and polyol pathway; the treatment of endothelial and platelet alterations; the improvement of the rheologic properties of blood.

[The physiopathologic bases of the neurotoxicity of phosphorus chelating agents containing soluble aluminum salts in patients with renal insufficiency]

To what extent can damage to the central and peripheral nervous systems be ascribed to chronic aluminum (Al) intoxication taken as a chelating agent for phosphorus, to limit hyperphosphatemia in uremic patients? Since Al is normally eliminated by the renal route, its accumulation in uremia has to be ascribed to a reduced or abolished renal clearance of the metal, which results in preferential toxicity for certain tissues, especially nervous tissue, which shows difficulty in eliminating Al, even after intake has been stopped. This review discusses, on the basis of toxicologic, experimental and clinical data, the possible pathogenic steps of Al neurotoxicity in uremia, considering: the damage to axonal transport in which Al intoxication tends to affect the components of the cytoskeleton, the polymerization phase of the alpha and beta tubulin constituents of neurotubules, and the normal translocation of neurofilaments from the perikaryon to more distal positions of the axon; the abnormalities in the brain pool of adrenergic, cholinergic and GABA neurotransmitters; the increase in permeability and changes in perm-selectivity of the blood-brain-barrier, with further loss of neurotransmitters and with acquisition, from the systemic circulation, of neurotransmitter-like substances such as hormones, monoamines and peptides, which may adversely modulate synaptic and membrane functions; the cerebral energy metabolism and particularly the hexokinase reaction, by Al replacement of the Mg-ion in the Mg-ATP complex, so that phosphorylation of glucose to G6P is blocked; the interaction of Al with calmodulin by displacement of the Ca-ion and subsequent formation of a stable Al-calmodulin complex with a cytotoxic effect due to the increase in the intracellular calcium concentration.(ABSTRACT TRUNCATED AT 250 WORDS)