Partial percutaneous discectomy for treatment of thoracolumbar disc protrusion: retrospective study of 331 dogs.

OBJECTIVES: To determine retrospectively the prognosis and outcome for dogs diagnosed with thoracolumbar intervertebral disc disease treated with partial percutaneous discectomy (PPD). METHODS: Three hundred and thirty-one dogs presenting with symptoms of thoracolumbar intervertebral disc disease from 1998 to 2003 were treated with PPD. Diagnosis and location of intervertebral disc disease was confirmed by clinical examination, radiography, myelography and magnetic resonance imaging. PPD was performed via fluoroscopy-guided removal of a 5 mm bore cylinder out of the central intervertebral space. RESULTS: Clinical success after surgery was achieved in 159 (88.8 per cent) grade II to IV patients and 58 (38.2 per cent) grade V patients. The mean (sd) time from percutaneous discectomy to first improvement was 8.3 (13.2) days. CLINICAL SIGNIFICANCE: The PPD approach to the thoracolumbar spine involves minor trauma (yielding rapid recovery) and less pain, and produces results comparable with open fenestration. Consequently, this simple minimal invasive technique can be recommended as an alternative to the technique of fenestration and can be easily performed in addition to open surgical decompression techniques or prophylactically. However, it is not a replacement for surgical treatment in dogs with thoracolumbar disc disease that require removal of disc fragments causing spinal cord or nerve root compression.

Treatment of 10 dogs with discospondylitis by fluoroscopy-guided percutaneous discectomy.

Ten dogs suffering from discospondylitis were treated by percutaneous discectomy and local and systemic antibiotic therapy. With fluoroscopic guidance, a cylinder 5 mm in diameter was removed from the centre of the intervertebral space, yielding a fenestration and decompressing the disc without producing any spinal instability. The causative bacteria were identified in nine of the 10 biopsy specimens, but in only three urine cultures and four blood cultures. In two cases, the antibiotics used initially had to be changed owing to the organisms' antibiotic resistance. The clinical signs of the dogs improved markedly after two to nine days (mean 4.2 days) and had resolved completely after five to 14 days (mean 9.1 days). In all the cases the disease could be classified histologically as either acute or chronic, and the disease was classified as chronic in one dog. No side effects were observed.

Comparison of intravenous coronary angiography using synchrotron radiation with selective coronary angiography.

Intravenous coronary angiography with synchrotron radiation is a novel and minimally invasive technique for coronary imaging. At the Hamburger Synchrotronstrahlungslabor HASYLAB at DESY, a dedicated angiography system has been developed, which has been shown to provide detailed images of coronary artery segments. For each scan, two monochromatic X-ray images below and above the K-edge of iodine were recorded simultaneously. The two images were subtracted logarithmically to produce a maximal contrast enhancement of the iodine. To date, the procedure has been carried out on 379 outpatients. No complications occurred during or after the angiographic procedure, and hospitalization was not required in any subject. The acceptance by patient is extremely high. Five outside reviewers, blinded as to the clinical data or prior angiographic interpretation, reviewed the images for the presence or absence of 70% or more occlusion of a vessel. They reached a sensitivity of 79% and a specificity of 99%. The study has demonstrated that the synchrotron method has satisfactory sensitivity and very high specificity for severe stenoses. The new method has several advantages over magnetic resonance imaging (MRI), electron beam computed tomography (EBCT), and multi-slice computed tomography (MSCT). Neither vascular calcification (CT) nor the presence of metal stents (MRI) impairs the evaluation of perfusion of segments of the coronary arteries. Furthermore, the spatial resolution is three or four times higher using synchrotron angiography, and problems due to respiratory motion are eliminated.

Intravenous coronary angiography using synchrotron radiation: technical description and preliminary results.

BACKGROUND: Standard coronary angiography requires an arterial access and catheters; intravenous coronary angiography may image coronary arteries noninvasively and without catheters. The aim of this study was the assessment of the diagnostic accuracy of intravenous coronary angiography validated by selective coronary angiography. METHODS: Seventy outpatients (80% males, mean age 62 +/- 8 years) underwent both standard and intravenous coronary angiography after a previous coronary intervention. Intravenous coronary angiography was performed within 6 weeks before or after selective coronary angiography. Two different projections were used to obtain 6-8 sequences per patient. Images were taken after injection of the contrast agent into the brachial vein or into the superior vena cava. During image acquisition, patients were moved through the scanning beam on a special chair. Thereafter, images were evaluated and compared to selective coronary angiograms for the following criteria: no stenosis, subsignificant stenosis (< 70%), significant stenosis (> or = 70%), and occlusion. RESULTS: One hundred eighty-seven target vessels were analyzed. In 50 target vessels one or more stents had been implanted. Seventeen target vessels were not analyzable due to inadequate image quality. The sensitivity of intravenous coronary angiography for the detection of lesions was 80% and the specificity was 95%. The sensitivity for the detection of significant lesions in the left anterior descending coronary artery was 84% (specificity 93%), in the left circumflex coronary artery 67% (specificity 90%), in the right coronary artery 85% (specificity 97%), and in bypass grafts 85% (specificity 97%). No complications were observed. CONCLUSIONS: Intravenous coronary angiography is efficacious and safe and allows quantification of lesions of the coronary arteries and of bypass vessels. Further advances in image processing are needed to improve sensitivity especially in the left circumflex coronary artery.

[Intravenous coronary angiography with synchrotron radiation]. / Intravenöse Koronarangiographie mit Synchrotronstrahlung.

INTRODUCTION: Coronary artery disease still remains the primary cause of death in the western industrialized world. Although the clinical value of selective coronary angiography (SCA) is beyond dispute, the associated risk of an invasive approach, the inherent costs and the necessary hospitalization have lead to the development and investigation of novel non-invasive techniques for coronary imaging. Intravenous coronary angiography (ICA) has been shown to permit non-invasive imaging of the coronary arteries. METHODS: In 66 pts (80% male, age 62 (+/- 8.5 yrs) after interventional therapy/CABG operation, ICA and a SCA were carried out within a time interval of < 6 weeks. After determination of the individual circulation time, contrast media (370 mg iodine/ml, 15 ml/s, 21 ml) was injected via a sheath in the cubital vein while the patient was sitting in an upright position in a specially designed scanning chair. In two different projections 6-8 images/patient were obtained for further image processing and evaluation. 182 target vessels had to be evaluated (LAD 55, Cfx 21, RCA 54, Grafts 52). In 50 target vessels one or more stents were implanted. RESULTS: 182 target vessels were evaluated according to the following criteria: no stenosis, < 70%, > = 70%, occlusion. Evaluation of the ICA and SCA images was performed by two independent investigators. Due to poor image quality, 17 vessels were not evaluated. The ICA findings were compared to that of SCA. For the LAD a sensitivity of 84% (specificity 93%), for the RCA a sensitivity of 85% (specificity 97%), for the Cfx a sensitivity of 67% (specificity 90%), and for grafts a sensitivity of 85% (specificity 97%) was calculated. CONCLUSION: ICA proved to be a feasible and safe technique for follow-up after coronary intervention/CABG operation on an outpatient basis. Evaluation of stents and severe calcification is possible. A good image quality provided, LAD RCA and grafts can be evaluated with an acceptable sensitivity and specificity. Due to superimpositioning the low sensitivity for the Cfx has to be compensated by further image processing.

[Radioiodine therapy in veterinary medicine: treatment of hyperthyroidism in a cat]. / Die Radioiodtherapie in der Veterinärmedizin: Behandlung der Schilddrüsenüberfunktion bei einer Katze.

A nine-year-old cat with symptoms of a distinct hyperthyroidism was presented at the University Hospital of the RWTH Aachen. The clinical symptoms as well as the diagnostic procedures performed at the hospital confirmed the diagnosis. After five weeks of thyreostatic medication a regular metabolism of the thyroid gland was established, followed by a radioiodine therapy with 70.3 MBq 131-iodine. Subsequently, the cat was hospitalized for two days before it could be released in good condition. Six weeks after treatment the former drastically reduced weight of the cat recovered to near normal. Even though the chemical analysis detected a discrete hyperthyroidism, clinical symptoms were no longer prominent. Three months after treatment, the final examination showed a regular metabolism of the thyroid gland without a specific thyroidal medication. The presented case illustrates that radioiodine therapy is a safe and efficient treatment of thyroidal dysfunctions in veterinary medicine.

[Sensory innervation of the hip joint capsule in dogs]. / Die sensible Innervation der Capsula articularis coxae beim Hund.

The innervation of the canine hip joint has become increasingly important in the treatment of hip dysplasia and hip arthrosis, since investigations proved that simple removal of periosteum around attachment of hip joint capsule, called denervation results in an instant analgesia and allows the dog to regain joyful freedom of movement. A macroscopic-anatomic examination of 16 canine hips furnished new findings and knowledge in the field of veterinary medicine on the sensitive innervation of the canine hip joint capsule. Accordingly, the craniolateral area of hip joint capsule is innervated by rami articulares of N. glutaeus cranialis, the caudolateral area by rami articulares of N. ischiadicus and the medial area by rami articulares of N. femoralis.

The influence of heat shock protein 70 induction on hemodynamic variables in a porcine model of recurrent endotoxemia.

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an attenuation of hemodynamic alterations and an altered pattern of inflammatory mediator release. Therefore, we measured main hemodynamic variables such as systemic and pulmonary artery pressure, cardiac output, heart rate, central venous pressure, and pulmonary artery wedge pressure, as well as the time-course of thromboxane-B2, 6-keto-PGF1 alpha, and interleukin 6 formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Circ Shock 35:237-244, 1991). Induction of the stress response was carried out by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenaspartate) = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 (HSP70) expression in the lungs, liver, and kidneys and significantly increased plasma levels of interleukin 6, 6-keto-PGF1 alpha, and thromboxane-B2, compared with untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators compared with the untreated group. Hemodynamic data presented significantly decreased peak pulmonary artery pressure and pulmonary vascular resistance index values, significantly increased systemic artery pressure and systemic vascular resistance index values, and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of HSP70 by Zn2+ attenuates the liberation of inflammatory mediators, as well as the course of hemodynamic variables due to LPS.

Induction of heat shock protein 70 by zinc-bis-(DL-hydrogenaspartate) reduces cytokine liberation, apoptosis, and mortality rate in a rat model of LD100 endotoxemia.

A prospective, randomized model of LD100/24 h endotoxemia was performed in male Wistar rats (n = 26; 250-300 g). The animals were divided into four groups: Group I (n = 5; saline treatment only), Group II (n = 5; Zn2+ treatment only), Group III (n = 8; saline pretreatment, lipopolysaccharide (LPS) treatment), and Group IV (n = 8; Zn2+ pretreatment, LPS treatment). Zn2+ pretreatment was carried out by intraperitoneal injection of 50 mg/kg zinc-bis-(DL-hydrogenaspartate) (10 mg/kg Zn2+). LD100/24 h endotoxemia was induced by intraperitoneal administration of 20 mg/kg LPS of the Escherichia coli strain WO111:B4. Tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 were detected by enzyme-linked immunosorbent assay (ELISA). HSP70 expression in the lungs, the liver, and the kidneys was determined by immunohistochemistry, Western blotting, and an HSP70 ELISA. Apoptosis was also detected by an in situ apoptosis detection kit (TUNEL) and a cell death detection ELISA, respectively. This rat model of endotoxemia proves the close relationship between HSP70 expression, cytokine liberation, and development of apoptosis. The data demonstrate that: 1) Zn2+ is a potent inducer of HSP70 expression; 2) the application of Zn2+ leads to slightly increased cytokine plasma levels; and 3) the manipulation of the heat shock response by Zn2+ significantly increases the survival rate after LD100 endotoxemia. Enhanced survival rate in animals pretreated with Zn2+ may be explained by increased tissue levels of HSP70, a subsequent significantly decreased liberation of the proinflammatory cytokines after LPS challenge, and a significantly decreased rate of apoptosis.

Influence of heat shock protein 70 and metallothionein induction by zinc-bis-(DL-hydrogenaspartate) on the release of inflammatory mediators in a porcine model of recurrent endotoxemia.

The manipulation of stress gene expression by heavy metals provides protection against the lethal effects of endotoxemia in murine models of septic shock. Recent in vitro studies with alveolar macrophages or monocytes show that induction of the stress response in these cells is followed by a decreased liberation of major cytokines [tumor necrosis factor-alpha (TNF alpha) and interleukin-1 (IL-1)] after endotoxin challenge. These findings suggest that the increased resistance to endotoxin in vivo after stress protein induction could be explained by an altered pattern of inflammatory mediator release. Therefore, we measured the time course of thromboxane-B2 (TxB2), 6-keto-PGF1 alpha, platelet activating factor (PAF), TNF alpha, interleukin-1 beta (IL-1 beta), and interleukin-6 (IL-6) formation with and without induction of the stress response in an established porcine model of recurrent endotoxemia (Klosterhalfen et al., Biochem Pharmacol 43: 2103-2109, 1992). Induction of the stress response was done by a pretreatment with Zn2+ (25 mg/kg zinc-bis-(DL-hydrogenasparate = 5 mg/kg Zn2+). Pretreatment with Zn2+ prior to lipopolysaccharide (LPS) infusion induced an increased heat shock protein 70 and metallothionein expression in the lungs, liver, and kidneys and increased plasma levels of TNF alpha, IL-1 beta, IL-6, and TxB2 as opposed to untreated controls. After LPS infusion, however, pretreated animals showed significantly decreased peak plasma levels of all mediators as opposed to the untreated group. The time course of mediator release was identical with the decreasing and increasing three peak profiles described previously. Hemodynamic data presented significantly decreased peak pulmonary artery pressures and significantly altered hypodynamic/hyperdynamic cardiac output levels in the pretreated group. In conclusion, the data show that the induction of stress proteins by Zn2+ could be a practicable strategy to prevent sepsis.

Differentiation of spontaneous canine breast tumors using dynamic magnetic resonance imaging with 24-Gadolinium-DTPA-cascade-polymer, a new blood-pool agent. Preliminary experience.

RATIONALE AND OBJECTIVES: The author assess the enhancement characteristics over time of spontaneous breast tumors in dogs comparing gadopentetate dimeglumine with a new blood-pool agent (24-gadolinium [Gd]-DTPA-cascade polymer). METHODS: Eighteen dogs with spontaneous breast tumors (5 carcinomas, 4 adenomas, and 9 benign mixed-tissue tumors) underwent dynamic magnetic resonance imaging after intravenous injection of gadopentetate dimeglumine and the blood-pool agent. Signal intensity time curves were followed up to 30 minutes after injection of both agents in the same animal. A nonlinear fitting routine enabled calculation of the delivery and clearance half lives of the contrast agent kinetics in each tumor. RESULTS: For gadopentetate dimeglumine, a fast signal increase was found immediately after intravenous injection, with a subsequent signal decay in all tumors. No difference was observed between the enhancement kinetics of different tumor types after gadopentetate dimeglumine application. Similar kinetics were found in benign lesions after injection of the blood-pool agent. However, in carcinomas the blood-pool agent displayed a slower delivery, delayed peak enhancement, and slower tumor tissue clearance or even a signal plateau of more than 30 minutes. CONCLUSIONS: Dynamic magnetic resonance imaging of breast neoplasms using a blood-pool agent may help to better differentiate between benign and malignant lesions because it demonstrates the enlarged interstitial space and increased capillary permeability in carcinomas.

Intravenous coronary angiography with dichromography using synchrotron radiation.

Dichromography represents a digital subtraction angiography mode based on energy substraction which allows imaging of fast moving subjects like the heart. For logarithmic subtraction 2 images with X-rays just below and above the iodine K-edge (33.17 keV) are simultaneously obtained in a line scan mode. Monochromatic X-rays of sufficient intensity to visualize coronary arteries of 1 mm diameter with extremely low iodine concentrations (1 mg/cm2) after venous injection is only provided by synchrotron radiation. The system NIKOS (non-invasive coronary arteriography with synchrotron radiation) at the Deutsches Elektronen Synchrotron (DESY) consists of 6 components: a wiggler, a monochromator, a safety system, a scanning device, a detector and a computer system. After experimental studies in dogs patients are imaged since 1990. Initial results demonstrate feasibility and safety of synchrotron radiation coronary angiography. Large scale studies are designed to further evaluate sensitivity and specificity. When compact synchrotron radiation sources become available, this technique could be used for follow-up studies and for evaluation of certain high coronary risk populations.

[The MRT of osteophytosis in experimental gonarthrosis]. / MRT der Osteophytose bei experimentellen Gonarthrosen.

PURPOSE: The value of MRI for the detection of knee osteophytosis was determined in an animal osteoarthritis model. METHODS: 10 dogs with experimentally induced unilateral osteoarthritis of the knee were investigated with MRI including 2-D-spin echo (SE) and 3-D-gradient echo (GE) imaging. The results were correlated with gross and histopathologic findings and with radiography. RESULTS: Osteophyte formation appeared early in the osteoarthritic process. Pathological analysis yielded 65 osteophytes. With 3-D-GE imaging, 91% of the osteophytes were detected, while 68% were visible on 2-D-SE images. With two-level radiography, 43% of the osteophytes were diagnosed. Additional use of tunnel view and conventional tomography increased the detection rate to 65%. Independent of the imaging technique, MRI revealed three different signal patterns of the osteophyte bone structure. Compared with the histologically evident fat marrow content and the grade of bone sclerosis, best agreement was achieved with 2-D-SE sequences. However, a discrepancy remained in 22%. A fibrocartilaginous layer at the osteophyte surface could be delineated especially on 3-D-GE images. CONCLUSIONS: MRI provides the highest standard in non-invasive diagnosis of osteophytes in the knee. 3-D-GE imaging in particular can demonstrate early and small osteophyte formation.

[MRI of the hyaline knee joint cartilages. Animal and clinical studies]. / MRT des hyalinen Kniegelenkknorpels. Tierexperimentelle und klinische Untersuchungen.

The value of MR imaging for the detection of hyaline cartilage lesions using 2-D spin-echo and 3-D gradient-echo imaging was evaluated in an animal experiment in 10 dogs and in a clinical study in 30 patients. MR imaging findings were compared with histopathological and arthroscopy findings, respectively. Using MRI neither grade I nor grade II hyaline cartilage lesions were detectable. In the animal experiments 77% of grade III lesions and all the grade IV lesions were seen. However, in the clinical study only about the half of grade III and IV lesions were detected. 3-D gradient-echo MR imaging was superior to 2-D spin-echo imaging (p < 0.001), while 3-D FLASH and 3-D FISP did not differ significantly in the detection rate (p < 0.34). 3-D gradient-echo MR imaging seems to be the best method for the delineation of high grade cartilage lesions. However, early stages of cartilage degeneration are invisible even with this imaging modality.

[Floating intracardiac metastasis]. / Flottierende intrakardiale Metastase.

Two years after the removal of an embryonic testicular tumour from a now 26-year-old man, his general health deteriorated and a holosystolic murmur was heard over the tricuspid valve area. A chest X-ray film demonstrated lung metastases. Biochemical tests were within normal limits, but the human chorionic gonadotrophin level was elevated to 81,030 mU/ml. Echocardiography revealed mild tricuspid regurgitation and a floating mass between the right atrium and ventricle, in contact with the tricuspid valve. The described findings did not support the diagnosis of embolus or inflammatory vegetation. Because of the danger of embolization and obstruction of the pulmonary outflow tract the mass was removed surgically. Enzyme-histological examination identified the tissue as a metastasis of the testicular tumour. The patient's condition at first improved, but he soon died of bleeding from the lung which was infiltrated by trophoblast-containing metastases of the testicular tumour.

Effect of dobutamine on pulmonary gas exchange in patients with severe heart failure.

Twenty patients (two female, 18 male, mean age 57 +/- 11 years) with severe heart failure NYHA IV (7 coronary artery disease, 13 congestive cardiomyopathy) were treated with 8.8 +/- 1.7 micrograms.kg-1 x min-1 of dobutamine. Pulmonary gas exchange was analysed by withdrawal of blood samples from a central venous catheter and a radial artery cannula. Dobutamine increased SvO2 from 58.7 +/- 11.2% to 72.2 +/- 6.3% (P = 0.0001) and decreased avDO2 from 7.7 +/- 2.45 Vol% to 4.97 +/- 1.34 Vol% (P = 0.0001). PaO2 and PaCO2 were not changed. Qs/Qt increased slightly from 9.1 +/- 8.3% to 11.3 +/- 6.4% (P = 0.035). Cardiac index increased by 51% (P = 0.0001), pulmonary capillary wedge pressure decreased by 28% (P = 0.0001). In patients with severe heart failure, dobutamine improved haemodynamics without detrimental effects on arterial oxygen concentration.

[Cardiovascular risk factors and restenosis after PTCA]. / Kardiovaskuläre Risikofaktoren und Restenosierung nach PTCA.

We prospectively investigated the influence of the cardiovascular risk factors hypercholesterolemia, smoking, diabetes mellitus, and arterial hypertension on the occurrence and extent of restenosis after successful coronary dilatation (PTCA). Of the 103 patients included in the study, control coronary angiography was obtained in 75 (73%) after 173 +/- 117 days. The restenosis rate (82 stenoses), defined as greater than or equal to 50% loss of initial gain in percent diameter stenosis, was 37%. Older age, male gender, and a history of diabetes mellitus were associated with a significantly increased mean extent of restenosis (p less than 0.05). In patients with hypertension, the initial success of dilatation was less than in controls without hypertension (p less than 0.05), and restenosis tended to be enhanced (p = 0.06). The risk of restenosis was unaffected by smoking and the presence of hypercholesterolemia. In spite of the mostly insignificant influence of single cardiovascular risk factors, the extent of restenosis clearly increased with the number of risk factors.

Residual platelet function under acetylsalicylic acid and the risk of restenosis after coronary angioplasty.

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) was shown not to be preventable by antiplatelet therapy; residual platelet function under treatment with platelet inhibitors could be one cause of this. Therefore, in a prospective investigation, residual platelet function was assessed in 98 patients treated with acetylsalicylic acid (ASA) on three occasions during the first 3 months after successful PTCA. Control cardiac catheterization was obtained in 75 of these patients (77%) with 82 dilated stenoses 173 +/- 117 days after PTCA. Restenosis, defined as diameter stenosis greater than or equal to 50% at control angiography, occurred in 41% of the dilated vessels, and 43% of patients experienced restenosis in at least one vessel. The in vitro platelet aggregatory response to either ADP (0.5, 1, and 10 microM) or collagen (1 and 5 mg/L) as aggregating agents did not differ between patients with and without restenosis. In addition, neither the collagen-stimulated in vitro synthesis of thromboxane nor the basal or prostaglandin E1-stimulated concentrations of cyclic AMP in platelet-rich plasma (PRP) was different in the two groups. There was no significant correlation between any of the parameters of platelet function assessed and the change in coronary luminal diameter observed between immediately after PTCA and control coronary angiography. The mean dose of ASA ingested during follow-up was also not a determinant of the occurrence of restenosis. Thus, residual platelet function under treatment with ASA as measured in vitro in this study, did not influence the occurrence of restenosis after successful PTCA.

Experimental hyaline cartilage lesions: two-dimensional spin-echo versus three-dimensional gradient-echo MR imaging.

The value of magnetic resonance (MR) imaging, with two-dimensional (2D) spin-echo and FISP (fast imaging with steady-state precession) and FLASH (fast low-angle shot) three-dimensional (3D) gradient-echo sequences, for the detection of hyaline cartilage defects of the femoral condyle and the tibial plateau, was investigated in an animal model. In eight dogs, the anterior cruciate ligament was transected in one knee joint, resulting in rapid development of osteoarthritis with degeneration of the hyaline cartilage. At autopsy, 24 cartilage lesions were found, which were classified into four grades. The overall detection of cartilage lesions with MR imaging was poor. Only five of the 24 lesions were visible on 2D spin-echo images, while 11 of 24 were visible on 3D FISP images and 15 of 24 were seen on 3D FLASH images. The best results were obtained in advanced stages of cartilage degeneration, involving ulceration and complete abrasion of the cartilage layer. Signal loss or signal intensity increase in the cartilage layer was seen inconsistently in grades 3 and 4 degeneration. In this animal model, 2D spin-echo imaging was inadequate for the diagnosis of hyaline cartilage lesions, while 3D gradient-echo imaging permitted satisfactory diagnosis in only grade 4 cartilage disease.

Age, cardiovascular risk factors and coronary heart disease as determinants of platelet function in men. A multivariate approach.

Older age, the cardiovascular risk factors and arteriosclerosis have been reported to be associated with stimulated platelet function. To evaluate the relative importance of these factors in determining platelet function, a cross-sectional multivariate study in 191 men, 113 healthy subjects and 78 patients with angiographically documented coronary heart disease, was performed. In healthy subjects, stepwise multiple linear regression identified age to be a major determinant of platelet aggregability. After induction with both ADP and collagen the platelet aggregatory response markedly increased with age. In the patients, platelet function was not age dependent. In multivariate analysis of variance, neither smoking status nor hypercholesterolemia (greater than or equal to 240 mg/dl) were determinants of platelet function in either group. An increase in systolic blood pressure was associated with slightly more inhibited ADP induced aggregation in both healthy subjects and patients with coronary heart disease. In patients compared to healthy subjects, aggregation after induction with ADP and collagen was markedly enhanced and the in vitro formation of thromboxane after collagen stimulation increased. Thus, by multivariate analysis, age and the presence or absence of coronary heart disease were found to be major determinants of platelet function. In contrast, the cardiovascular risk factors smoking, hypercholesterolemia and hypertension were associated with only minor or no alterations of platelet function.