New in vivo measurements of pressures in the intervertebral disc in daily life.

STUDY DESIGN: We conducted intradiscal pressure measurements with one volunteer performing various activities normally found in daily life, sports, and spinal therapy. OBJECTIVES: The goal of this study was to measure intradiscal pressure to complement earlier data from Nachemson with dynamic and long-term measurements over a broad range of activities. SUMMARY OF BACKGROUND DATA: Loading of the spine still is not well understood. The most important in vivo data are from pioneering intradiscal pressure measurements recorded by Nachemson during the 1960s. Since that time, there have been few data to corroborate or dispute those findings. METHODS: Under sterile surgical conditions, a pressure transducer with a diameter of 1.5 mm was implanted in the nucleus pulposus of a nondegenerated L4-L5 disc of a male volunteer 45-years-old and weighing 70 kg. Pressure was recorded with a telemetry system during a period of approximately 24 hours for various lying positions; sitting positions in a chair, in an armchair, and on a pezziball (ergonomic sitting ball); during sneezing, laughing, walking, jogging, stair climbing, load lifting during hydration over 7 hours of sleeping, and others. RESULTS: The following values and more were measured: lying prone, 0.1 MPa; lying laterally, 0.12 MPa; relaxed standing, 0.5 MPa; standing flexed forward, 1.1 MPa; sitting unsupported, 0.46 MPa; sitting with maximum flexion, 0.83 MPa; nonchalant sitting, 0.3 MPa; and lifting a 20-kg weight with round flexed back, 2.3 MPa; with flexed knees, 1.7 MPa; and close to the body, 1.1 MPa. During the night, pressure increased from 0.1 to 0.24 MPa. CONCLUSIONS: Good correlation was found with Nachemson's data during many exercises, with the exception of the comparison of standing and sitting or of the various lying positions. Notwithstanding the limitations related to the single-subject design of this study, these differences may be explained by the different transducers used. It can be cautiously concluded that the intradiscal pressure during sitting may in fact be less than that in erect standing, that muscle activity increases pressure, that constantly changing position is important to promote flow of fluid (nutrition) to the disc, and that many of the physiotherapy methods studied are valid, but a number of them should be re-evaluated.

Noncalcified pulmonary hamartomas: computed tomography enhancement patterns with histologic correlation.

The objective of this study was to correlate contrast-enhanced computed tomography images of noncalcified hamartomas with histologic specimens to find specific computed tomography enhancement patterns. Over 4 years, 30 noncalcified hamartomas were surgically resected. Enhanced computed tomography images of these hamartomas were reviewed and correlated with histologic findings. Contrast-enhancing septa were present in 24 of 30 hamartomas (80%). Five hamartomas (15%) showed a nonspecific enhancement pattern. The presence of an air bronchogram was a rare finding (5%). Comparison between computed tomography images and pathologic specimens showed that areas with less enhancement corresponded to cartilagineus tissue, and enhancing septa corresponded to loose connective tissue within the cartilagineus core. The rare finding of an air bronchogram corresponded to bronchial epithelium within cartilagineus tissue.

The challenge of solitary pulmonary nodules: HRCT evaluation.

Both enhancement and morphologic analysis have been shown important in the HRCT study of solitary pulmonary nodules (SPNs). In our prospective study, 25 adult patients with benign (N = 8) or malignant (N = 17) SPNs were examined before and after contrast agent. We obtained three serial thin section CT scans every 60 s after the onset of the injection of contrast material. All 17 malignant nodules did enhance very significantly (P < 0.001). Benign nodules did not enhance significantly (P > 0.05). Using 20 HU as a threshold for positivity of the contrast test, our sensitivity was 100%, specificity was 74%, positive predictive value was 89.5%, negative predictive value was 100%, and accuracy was 92%; test bias was 1.118. In our opinion, HRCT evaluation of SPNs is the most widely available tool to save cost and decline in morbidity in management.

[Elastic system in human gingiva in health and periodontal disease]. / Sistema elástico en encias humanas con salud y enfermedad paradencial.

We processed 28 samples of human gingiva in health or paradential illness, of 15 patients between 20 to 67 years old. In 306 histologies cuts we made different staining to light microscope. We analyzed presence, distribution, diameter and relations of the elastic, elaunin and oxytalan fibers. The patron of distribution fibrilar of the elastic system gingival was different than other zones of the body. The description had made in three zones of the gingival connective tissue: deep, subpapilar and papilar zones. The elastic fibers had less numerous and larger diameter than the elaunin y oxytalan ones. Their repair was irregular. The elaunin followed the colagen fibers. The oxytalan formed delicates nets in the lodge of connective tissue, inflamatories infiltrates and interfibrilar spaces. They came to the basal membrane perpendicularly or oblicualy, isolated or in little bundles. The fibers of elastic system increased principaly in inflamed gingiva of teeth with overburden, though they supported the low proportion that exist at health gingiva. They appeared at the little vases wall and were increased at zones next to edentate spaces. The analogy and close entail between the elaunin and oxytalan fibers to colagen ones, made think in a relation of reenforcement of colagen, increased at paradential illness.

Acquired selective factor X deficiency in acute nonlymphocytic leukemia.

A case of acute nonlymphocytic leukemia (ANLL) and selective acquired FX deficiency at presentation is reported. The deficiency was not corrected by the infusion of fresh frozen plasma, but the patient's plasma had no neutralizing activity in vitro. The cause of the deficiency is unknown.

Sorting of two polytopic proteins, the gamma-aminobutyric acid and betaine transporters, in polarized epithelial cells.

The gamma-aminobutyric acid transporter (GAT-1) isoform of the gamma-aminobutyric acid and the betaine (BGT) transporters exhibit distinct apical and basolateral distributions when introduced into Madin-Darby canine kidney cells (Pietrini, G., Suh, Y. J., Edelman, L., Rudnick, G., and Caplan, M. J. (1994) J. Biol. Chem. 269, 4668-4674). We have investigated the presence of sorting signals in their COOH-terminal cytosolic domains by expression in Madin-Darby canine kidney cells of mutated and chimeric transporters. Whereas truncated GAT-1 (DeltaC-GAT) maintained the original functional activity and apical localization, either the removal (DeltaC-myc BGT) or the substitution (BGS chimera) of the cytosolic tail of BGT generated proteins that accumulated in the endoplasmic reticulum. Moreover, we have found that the cytosolic tail of BGT redirected apical proteins, the polytopic GAT-1 (GBS chimera) and the monotopic human nerve growth factor receptor, to the basolateral surface. These results suggest the presence of basolateral sorting information in the cytosolic tail of BGT. We have further shown that information necessary for the exit of BGT from the endoplasmic reticulum and for the basolateral localization of the GBS chimera is contained in a short segment, rich in basic residues, within the cytosolic tail of BGT.

Axonal neuropathy associated with interferon-alpha treatment for hepatitis C: HLA-DR immunoreactivity in Schwann cells.

A 44-year-old man developed a peripheral neuropathy during treatment with interferon-alpha for chronic hepatitis C. The onset was insidious, beginning symmetrically in the hands with paresthesia. Neurophysiological investigation revealed a predominantly sensory axonal neuropathy. A sural nerve biopsy confirmed primary axonal damage. Immunofluorescence studies showed increased expression of HLA-DR molecules prevalently on Schwann cells of non-myelin-forming type.

[Computerized tomography in the evaluation of the larynx after surgical treatment and irradiation]. / Valutazione mediante tomografia computerizzata della laringe dopo trattamento chirurgico e irradiazione.

INTRODUCTION: The follow-up of the patients submitted to surgery for laryngeal carcinoma requires both clinical and CT examinations, particularly in the cases at high risk of recurrence. Our series consisted of 72 laryngeal carcinoma patients operated on and regularly followed-up with CT to distinguish relapse from normal or abnormal postoperative changes. MATERIALS AND METHODS: Seventy-two laryngeal carcinoma patients were submitted to surgery: total laryngectomy was performed in 33 cases, supraglottic laryngectomy in 16 cases, Labayle subtotal laryngectomy in 18 cases and Mayer Piquet subtotal laryngectomy in 5 cases. The patients were followed-up postoperatively with CT and 94 examinations were performed in all; pathology was performed in all the cases with radiologic suspicion of recurrence (19 patients) and further clinical examinations were performed to exclude recurrence in the 14 cases where imaging findings were questionable. RESULTS AND DISCUSSION: Local recurrences were confirmed in 16 of 19 patients with positive CT findings. Radiologically, the recurrence appeared as an irregular thickening of the pharyngo-laryngeal wall with inhomogeneous density after i.v. contrast agent infusion. The patients submitted to total or supraglottic laryngectomy recurred most often at the cranial site of resection (5/6 cases), those submitted to Labayle surgery at the mucosa adjacent to the cricoarytenoid unit (3/3 cases) and those submitted to Mayer Piquet surgery in the supraglottic region. Two more patients submitted to emergency tracheotomy recurred at this level. Lymph node recurrences were found in 6 total laryngectomy patients. Misinterpretations were most frequently due to postirradiation changes (5 of 14 cases) or to atypical postoperative images (4/14 cases). Three more patients presented a secondary lesion misinterpreted as a relapse. CONCLUSIONS: Our results confirm the role of CT in the follow-up of the patients operated on for laryngeal carcinoma when CT findings are closely correlated with clinical and endoscopic results, permitting to correctly assess the extent of relapse and possible nodal spread.

[The solitary pulmonary nodule: the preliminary results in differential diagnosis by high-resolution computed tomography with a contrast medium]. / Il nodulo polmonare solitario: risultati preliminari sulla diagnosi differenziale mediante Tomografia Computerizzata con alta risoluzione con mdc.

INTRODUCTION: High-resolution computed tomography (HRCT) with iodinated contrast material has been used by many authors to study solitary pulmonary nodules (SPNs). The degree of enhancement was correlated with the nodule malignancy. MATERIAL AND METHODS: Forty adult patients were examined, before and after contrast agent administration, with incremental dynamic CT. We selected 22 patients with SPNs (3-30 mm phi, except one with 40 mm phi). The CT numbers of the inner nodule were calculated before and 1, 2 and 3 minutes after the i.v. administration of a weight-related dose (1.5 mL/kg/min) of nonionic iodinated contrast agent. A dose of 100 mL contrast agent was used in the first 6 patients. The difference in CT numbers between unenhanced images and the images with maximum enhancement (max. attenuation) was also calculated. RESULTS: Histologic diagnoses included 4 tuberculomas, 3 hamartomas and 15 malignant tumors (9 adenocarcinomas, 5 squamous cell carcinomas and 1 non-Hodgkin lymphoma). The CT numbers (in Hounsfield units, HU) of malignant nodules ranged 12-31 HU (mean: 21.5 HU) before contrast agent administration; the "long-standing" tuberculomas ranged 11-22 HU (mean: 16.5 HU) and the hamartomas had a mean density of 10.5 HU. We excluded for the study two "fresh" tuberculomas, one of which was surrounded by a low-attenuation infiltrate (the halo sign). We selected a threshold value of 20 HU on enhanced CT images to distinguish malignant (> or = 20 HU) from benign (< or = 20 HU) nodules. All lung cancers had complete enhancement (mean density: 35.5 HU). With 20 HU as the threshold value for a positive test, sensitivity was 100%, specificity 85.7%, positive predictive value 93.8% and negative predictive value 100%; test bias was 1.067. CONCLUSION: Positron emission tomography (PET) with 2-[fluorine-18] fluoro-2-deoxy-D glucose is reported to be as accurate as enhanced HRCT, but it does not provide accurate morphological information, is not widely available and it is quite expensive: therefore, in our opinion, CT should be preferred. After examining over 100 patients, we may use our results in the decision analysis comparing surgical risk with cancer risk.