Two conformational polymorphs of 4-methylhippuric acid.

4-Methylhippuric acid {systematic name: 2-[(4-methylbenzoyl)amino]ethanoic acid}, a p-xylene excreted metabolite with a backbone containing three rotatable bonds (R-bonds), is likely to produce more than one stable molecular structure in the solid state. In this work, we prepared polymorph I by slow solvent evaporation (plates with Z' = 1) and polymorph II by mechanical grinding (plates with Z' = 2). Potential energy surface (PES) analysis, rotating the molecule about the C-C-N-C torsion angle, shows four conformational energy basins. The second basin, with torsion angles near -73°, agree with the conformations adopted by polymorph I and molecules A of polymorph II, and the third basin at 57° matched molecules B of polymorph II. The energy barrier between these basins is 27.5 kJ mol-1. Superposition of the molecules of polymorphs I and II rendered a maximum r.m.s. deviation of 0.398 Å. Polymorphs I and II are therefore true conformational polymorphs. The crystal packing of polymorph I consists of C(5) chains linked by N-H...O interactions along the a axis and C(7) chains linked by O-H...O interactions along the b axis. In polymorph II, two molecules (A with A or B with B) are connected by two acid-amide O-H...O interactions rendering R22(14) centrosymmetric dimers. These dimers alternate to pile up along the b axis linked by N-H...O interactions. A Hirshfeld surface analysis localized weaker noncovalent interactions, C-H...O and C-H...π, with contact distances close to the sum of the van der Waals radii. Electron density at a local level using the Quantum Theory of Atoms in Molecules (QTAIM) and the Electron Localization Function (ELF), or a semi-local level using noncovalent interactions, was used to rank interactions. Strong closed shell interactions in classical O-H...O and N-H...O hydrogen bonds have electron density highly localized on bond critical points. Weaker delocalized electron density is seen around the p-methylphenyl rings associated with dispersive C-H...π and H...H interactions.

Massive rise in thyroglobulin with adult respiratory distress syndrome after embolisation of thyroid cancer metastasis.

A patient with long-standing metastatic disease from a well differentiated papillary cell carcinoma of the thyroid underwent embolisation of a painful large sacral metastasis. Following embolisation she had a massive rise in circulating serum thyroglobulin (Tg) levels coinciding with the development of adult respiratory distress syndrome (ARDS) on the tenth day without any other obvious cause. The patient subsequently recovered. The time course suggests that ARDS in this case might have resulted from aggregation of Tg molecules in the pulmonary microcirculation.

A prospective study of soft-tissue ultrasonography in sickle cell disease patients with suspected osteomyelitis.

AIM: A prospective study was done to assess the accuracy of soft tissue ultrasonography in patients with sickle cell disease (SCD) presenting with suspected osteomyelitis. MATERIALS AND METHODS: Thirty-one SCD patients had soft tissue ultrasonography on 38 occasions (18 men, 13 women; mean age 8.2 years). The initial ultrasonographic signs and diagnosis were compared with the final clinical diagnosis, which was based on clinical progress and scintigraphy. RESULT: The overall sensitivity of ultrasound in diagnosing osteomyelitis was 74% with a specificity of 63%. The principal ultrasonographic finding of subperiosteal fluid was present in 14 (74%) patients with osteomyelitis and seven (37%) patients without infection. A finding of a subperiosteal fluid depth of 4 mm or more was significantly associated with osteomyelitis (P < 0.01). CONCLUSION: Ultrasonography should be the initial investigation in SCD patients if osteomyelitis is suspected clinically. In such a clinical setting, a finding of 4 mm depth or more of subperiosteal fluid appears to be diagnostic. Previous statements that the presence of any subperiosteal fluid indicates infection are shown to be inaccurate. Patients with less than 4 mm of subperiosteal fluid require further imaging or aspiration to establish the diagnosis of osteomyelitis.

Thoracic ectopic kidney in an adult.

We are presenting an adult patient with a rare form of renal ectopy. Our patient had a thoracic kidney with complications. He presented with symptoms unrelated to the urinary system and his chest x-ray showed an intrathoracic mass presenting just above the diaphragm. An excretory urogram may be necessary for the diagnosis in such patients with similar chest x-ray findings.

CT features of olivopontocerebellar atrophy in children.

Between 1990 and 1992, 14 children were seen in whom a clinical diagnosis of olivopontocerebellar atrophy (OPCA) had been made. The majority of patients presented with cerebellar ataxia and hypotonia. Five children had a family history of a similar illness in first-degree relatives. All cases had undergone clinical and neurologic examinations, routine laboratory tests and cranial CT. CT features were graded to quantitate the degree of atrophy in each cerebellar hemisphere, vermis and brain stem. All patients had varying degrees of atrophic changes of cerebellum, brain stem and cerebrum. These CT features appear to be distinctive enough to enable the diagnosis of OPCA to be made.

A new technique for nonsurgical repair of peripheral pseudoaneurysm.

Peripheral vascular lesions may be inaccessible to treatment using catheter techniques. Ultrasound imaging in combination with Doppler may identify such lesions and provide possibilities for image-guided compression, injection of embolizing material by direct puncture, or both.

A double-blind study of iopromide 300 for peripheral arteriography. Results of a multi-institutional comparison of iopromide with iohexol and iopamidol.

RATIONALE AND OBJECTIVES: The use of nonionic contrast media for peripheral angiography has been well established in various reports. These agents provide the clinical benefit of decreased pain and heat sensations thought to be a function of osmolality, viscosity, and vasodilation. Iopromide is a new nonionic contrast medium that has been extensively studied for both intravenous (i.v.) and intraarterial indications. This study compares iopromide with similar concentrations of two other nonionic agents to evaluate their efficacy, tolerance, and adverse effects in peripheral angiography. METHODS: Two prospective, double-blind, randomized comparative clinical trials compared the safety profile, tolerance, and diagnostic quality of iopromide with two control drugs, iopamidol and iohexol. Eighty-one patients received iopromide, 19 received iohexol, and 40 received iopamidol. The trials evaluated potential changes in routine hematologic, biochemical, and renal function studies up to 72 hours after completion of the studies. Efficacy evaluation was performed by a physician who was blinded to the contrast used. Tolerance and adverse effects were determined by questionnaire, direct observation, and chart review. RESULTS: Demographic parameters were comparable among the three study sites. There was no difference in vessel visualization or diagnostic quality of the examination among the three agents. Minor adverse events occurred in all groups. Serious adverse events were, in almost all instances, thought to be secondary to factors other than the contrast media administered. CONCLUSIONS: This study confirms the safety and efficacy of iopromide (300 mg I/mL) for peripheral arteriography. Its safety and efficacy profiles are comparable with those of iopamidol and iohexol at similar concentrations and dosage.

Angioplasty gives good results in critical lower limb ischaemia. A 5-year follow-up in patients with known ankle pressure and diabetic status having femoropopliteal dilations.

137 consecutive patients with known ankle pressures and diabetic status had attempted femoro-popliteal dilatation for lower limb ischaemia in an English provincial teaching hospital. All except one were followed until failure or death to assess survival and amputation rates. Non-diabetic patients with critical limb ischaemia had a 5 year survival rate of 62.2% (SE 17.1) compared to 50.5% (SE 7.0) for claudicants, with no significant difference on logrank testing. Diabetics had a relative risk of amputation of 11.2 compared to nondiabetics. Patients with pre-treatment ankle pressures of 50 mm or less had a relative risk of amputation of 2.6 compared to those with higher resting pressures. It is concluded that angioplasty should be the treatment of first choice in critical lower limb ischaemia whenever it is technically possible. Including patients with rest pain in the critical ischaemia group does not significantly affect cumulative patency rates.

Audit of quality in a radiological department--a pilot study.

As part of the development of an auditing system for this department, a pilot study was designed to audit the quality of the product leaving the department. One hundred and six patient investigations were reviewed. For each investigation 26 items which were considered to reflect the quality of information on the request card, the films, the report and the condition of the film packets were assessed using a simple scoring system. Overall performances for various aspects of the departmental 'product', and for groups of staff within the department, were derived from these scores. Several problem areas were identified. Individual items were then scrutinized for recurring low scores and where scores fell outside a predetermined range steps were taken to improve standards. The scoring system developed is simple, easy and effective in use. It is considered that audit of quality is worthwhile and should be extended to become a routine part of departmental management.

Failure of peripheral arterial balloon angioplasty: does platelet deposition play a role?

The pathophysiological response to peripheral percutaneous transluminal balloon angioplasty in 20 patients was investigated using 111-Indium labelled platelets. Platelet deposition was quantified by measuring the degree of radioactivity uptake at angioplasty and control sites using a computer linked system and expressing the uptake as a ratio of angioplasty/control. Following platelet labelling, scans were performed before angioplasty and at 1, 24 and 48 h after angioplasty. To assess patency of the angioplasty, ankle brachial Doppler pressure indices were performed and supported by repeat angiograms if doubt of patency existed. All patients were followed-up at 1 week, 1 month and 6 months to correlate the degree of early platelet uptake with failure. The mean +/- sem platelet radioactivity ratio at the angioplasty site increased from 1.1 +/- 0.1 prior to the procedure to a peak of 2.1 +/- 0.3 at 1 h (p less than 0.01), 1.6 +/- 0.2 at 24 h (p less than 0.05), and 1.7 +/- 0.3 at 48 h (p less than 0.05). Angioplasties that failed within 6 months tended to have a higher maximum early platelet uptake (3.1 +/- 0.6) compared to successful angioplasties (1.9 +/- 0.3) but the difference was not significant in the numbers studied. This study provides a suitable model to assess the role of platelet accumulation in angioplasty failure and the influence of various antiplatelet regimes.

Fracturing and stretching of angioplasty balloon catheters under bending with tension.

Eight catheters from five manufacturers have been subjected to tests which combined bending and tension. Three failure mechanisms have been identified. These included separation of the balloon from its proximal attachment to the shaft, fracture of the shaft at its junction with the balloon, and undue ductility of the shaft. It is concluded that good catheter design should ensure that there is no sudden change in stiffness along the length of the catheter, and that the optimum relationship of ductility to stiffness has not yet been defined for catheters. Recommendations relating to these characteristics could be included in the British Standards relating to angioplasty balloon catheters.

Complications in percutaneous transluminal angioplasty: relationships with patient age.

Five hundred consecutive attempted lower limb angioplasties for ischaemic disease (370 patients, mean age 65.6 years, range 33-91 years) were reviewed. Significant complications occurred in 44 cases (8.8%). Nine patients (1.8%) underwent emergency surgery related to a complication. A further 12 patients (2.4%) underwent elective surgery related to a complication. In addition, four patients died within 30 days of the procedure; one following surgery performed because of a complication of angioplasty, one following a myocardial infarction, one following severe bleeding associated with subsequent thrombolytic therapy and one during emergency surgery related to a complication of angioplasty. A correlation was found between complication rate and age. This relationship was independent of the approach to, the position of, and the severity of the treated lesion. Elderly patients are at increased risk of complication in lower limb angioplasty.

Fate of patients undergoing transluminal angioplasty for lower-limb ischemia.

A prospective study of 370 patients who underwent 500 percutaneous transluminal angioplasties (PTAs) for lower-limb ischemia over a 7-year period was performed. A 97% follow-up rate was achieved. The first PTA was successful in 188 patients (51%). Of the failures, 31% were failed attempts at dilation and 73% occurred within 1 month of intervention. Of the patients with failed PTA, 39% underwent bypass surgery and 24% underwent amputation. The 30-day mortality rate was 3%, with 1% of the deaths attributed to PTA. The survival rate at 5 years for the successes was double that for the failures (P less than .0005). The best results were in femoropopliteal stenoses with two or three patent calf vessels (cumulative patency rate, 78% at 3 years) and the worst in femoropopliteal occlusions with one or no patent calf vessels (cumulative patency rate, 25% at 3 years). Log rank tests on the life-table data were used to show factors favoring a good outcome. It is concluded that PTA is the treatment of first choice in suitable patients and, although the failure of intervention in critical ischemia has a significant risk, it is a valuable addition to the therapeutic options in patients with little chance of surgical treatment.

Role of duplex scanning in the selection of patients for carotid endarterectomy.

A retrospective review of 63 patients undergoing duplex scanning and angiography for suspected carotid artery disease was performed to evaluate the need for routine angiography before carotid endarterectomy. A consultant surgeon (M.H.) made a simulated management decision on the basis of a clinical summary and a duplex scan report. Twenty-four patients were selected for surgery without angiography; duplex scanning had a sensitivity of 100 per cent and a specificity of 90 per cent in the detection of internal carotid artery stenosis. In two cases duplex scanning misdiagnosed a total occlusion as a critical stenosis. Eighteen patients failed to meet the criteria for surgery and were referred for angiography. Twenty-one patients were selected for conservative treatment on the basis of the duplex scan report. Combining the surgical and conservative groups (45 patients), duplex scanning had a sensitivity of 96 per cent and specificity of 95 per cent for the detection of stenosis greater than 50 per cent. In the identification of a total occlusion, duplex scanning had a poor sensitivity of 50 per cent. These results suggest that routine angiography before carotid endarterectomy is unnecessary in selected patients but that a suspected occlusion should be confirmed by angiography.

Randomized trial of laser-assisted passage through occluded femoro-popliteal arteries.

A randomized trial was carried out in patients with occlusions of the femoro-popliteal artery to compare the passage of metal-tipped optical fibres with guide wires and catheters through the occlusions, prior to balloon angioplasty. The study was in a provincial English teaching hospital providing a vascular service for the area. Fifty patients were entered; 25 into the "laser" group and 25 into the "control" group. End points were (a) the success in passage through the occlusion and (b) the outcome 1 month after passage. Comparison of the groups showed no appreciable difference between the two methods with regard to age, sex, symptoms, incidence of diabetes, or previous myocardial infarctions. Successful passage through the occlusion followed by dilatation was achieved in 18 (72%) patients in the laser group and 20 (80%) in the control group. After 1 month, 13 (52%) arteries in the laser group were patent compared to 13 (57%) in the control group. Confidence limits for the difference in success of passage are -15% to +31%, and -24% to +33% for patency after 1 month. Since these limits include zero, it is unlikely that a longer trial would alter the difference between the two methods. The results suggest that the laser system currently in use is no better than conventional methods.