The influence of the peptide chain on the kinetics and stability of microperoxidases

Microperoxidases with increasing lengths of the peptide attached to the heme moiety have been isolated after proteolytic digestion of horse-heart cytochrome c (microperoxidases 6, 8, and 11) and of cytochrome c550 from Thiobacillus versutus (microperoxidase 17). The different microperoxidases catalyze the H2O2-dependent para-hydroxylation of aniline relatively efficiently but are rapidly inactivated under turnover conditions. The horse-heart cytochrome-c-derived microperoxidases have identical values for Vmax but show a decrease of the K(m) for aniline and a higher stability when the attached peptide is longer. The kinetic constants obtained for microperoxidase 17, differ markedly from the microperoxidases derived from horse-heart cytochrome c. Possible factors underlying the observed differences are discussed.     

Single photon emission computed tomography-EEG relations in temporal lobe epilepsy

The role of single photon emission computed tomography (SPECT) as an independent confirmation test in presurgical evaluation of medically intractable temporal lobe epilepsy has not been critically investigated. Because spreading ictal discharges may cause a concomitant increase of cerebral blood flow in remote cerebral regions, a careful analysis of peri-injection EEG patterns and their relation to ictal SPECT may be important in evaluating the reliability of ictal SPECT. Both interictal and ictal EEG and SPECT were reviewed in 19 patients with temporal lobe epilepsy who achieved a successful seizure outcome after surgery. Patients were divided into unitemporal and bitemporal groups according to the lateralization of interictal epileptiform discharges (IED). Ictal EEG features were classified into lateralized and nonlateralized groups. The concordance between SPECT and EEG lateralizations was examined in each patient and correlated to the documented epileptogenic temporal lobe. Interictal SPECT correctly lateralized in eight of nine patients with unitemporal IED and in five of 10 patients with bitemporal IED. Ictal SPECT was highly concordant with the peri-injection ictal EEG but correctly lateralized the epileptogenic region in only 11 of 19 patients. When both pre- and postinjection EEG epochs lateralized ipsilaterally, all ictal SPECT images showed concordant lateralization. If pre- and postinjection EEG epochs were either different in lateralization or nonlateralization, ictal SPECT images often showed complex patterns of cerebral perfusion with a high incidence of false lateralization. Interictal SPECT was more sensitive and reliable in patients with unitemporal IED than in patients with bitemporal IEDs. Ictal SPECT was closely related with peri-injection EEG epochs but with frequent false lateralization. The role of ictal SPECT as an independent confirmation test in presurgical evaluation should be reappraised.     

Usefulness of argyrophilic nucleolar organizer regions score to differentiate suspicious malignancy in pulmonary cytology

OBJECTIVE: Pulmonary cytologic specimens reported as "suspicious for malignancy" pose problems in clinical management. Silver staining for argyrophilic nucleolar organizer regions (AgNOR) has proved useful in making a cytopathologically differential diagnosis between benign and malignant cells. This study aimed to evaluate the usefulness of AgNOR score in the diagnosis of pulmonary cytologic specimens deemed inconclusive by conventional staining methods. METHODS: Pulmonary cytologic specimens initially reported as suspicious for malignancy with Papanicolaou or May-Grünwald-Giemsa (MGG) staining obtained from 35 proved cases were destained then restained using the AgNOR technique. Another 35 cases with clear cytologic diagnosis were also examined for comparison. The median number of dots, defined as the AgNOR score, was used to differentiate malignant from benign specimens. RESULTS: Malignant cases had significantly higher AgNOR scores than benign ones (p<0.001). There were no significant differences among smears previously stained with Papanicolaou or MGG method, among specimens obtained via bronchoscopic brushing, fine-needle aspiration of lung or pleural effusion, or among subgroups of malignant diseases. Based on the results of our previous study, the cutoff value of the AgNOR score to differentiate benignancy from malignancy was set at 6. At this setting, the sensitivity and specificity of AgNOR score were 88% and 80%, respectively, in aiding a differential diagnosis of pulmonary cytologic specimens initially classified as suspicious for malignancy. For those cases with a clear cytologic diagnosis, the sensitivity and specificity of AgNOR score were 92% and 100%, respectively. For all cases, the sensitivity of AgNOR score was 90% and the specificity was also 90%. CONCLUSIONS: The AgNOR score is of value in aiding a differential diagnosis between benign and malignant lesions in pulmonary specimens with equivocal cytologic features.     

Risk factors for delayed graft function in cadaveric kidney transplantation: a prospective study of renal function and graft survival after preservation with University of Wisconsin solution in multi-organ donors. European Multicenter Study Group

BACKGROUND: Delayed graft function (DGF) remains an important complication in renal transplantation. In this multicenter study, we investigated the influence of donor and recipient factors on the occurrence of DGF and DGF's effect on long-term graft survival. METHODS: A total of 547 transplanted kidney allografts, retrieved from multi-organ donors, were analyzed, and results were compared with literature on kidney-only donors. RESULTS: Median follow-up of patients without graft failure was 3.4 years. Twenty-four percent of the recipients developed DGF. In univariate analysis, the following factors significantly increased the incidence of DGF: (a) among the donor factors, mean creatinine level >120 micromol/L and prolonged cold ischemia time (CIT); and (b) among the recipient factors, previous transplant(s), no intraoperative use of mannitol, poor quality of reperfusion, absence of intraoperative diuresis, and pretransplant anuria or oliguria. After stepwise logistic regression, donor age, CIT, recipient's number of previous transplants, and intraoperative diuresis proved to be of independent prognostic value for the occurrence of DGF. Overall graft survival was 91%, 87%, and 72% at 3 months, 1 year, and 4 years after transplantation, respectively. In case of DGF, graft survival was approximately 10% lower when compared with cases with immediate graft function (P<0.001). No difference in incidence of DGF was found between grafts of multi-organ donors and kidney-only donors. CONCLUSIONS: DGF results in an approximately 10% higher rate of graft failure. DGF incidence can be reduced by the administration of mannitol during transplantation, which minimizes CIT and optimizes donor management. Grafts from multi-organ donors and kidney-only donors appear to be of equal quality.     

Value of Doppler color ultrasonography in diagnosis of arterial occlusive disease of the lower extremity. A direct comparison with percutaneous angiography

A Direct Comparison with Percutaneous Angiography: AIM: To compare colour-coded Doppler sonography (CCDS) with conventional angiography in severe occlusive vascular disease of the lower limb. METHODS: In 55 patients 1141 vessel segments were evaluated, 700 of them with atheromatous plaques, 270 with stenoses, 208 with occlusions and 6 with aneurysms. RESULTS: Deeper-seated vessels such as the abdominal aorta, the pelvic arteries, the superficial femoral artery at the level of the adductor canal and parts of the lower leg arteries are less accessible for direct CCDS. Many pathological changes however can be diagnosed indirectly by changes in the spectral wave form distal to the lesion. In superficial vascular segments (the common femoral artery, the profunda femoris artery, the superficial femoral artery above the adductor canal and the popliteal artery) image quality was excellent, more pathological changes were found, and the degree of stenosis was better estimated in comparison to angiography. CONCLUSION: The value of CCDS in patients with intermittent claudication is limited to those who have been examined with angiography e.g. before angioplasty, to follow-up examinations after vascular dilatation or surgery and to supplementary visualisation after angiography especially in readily accessible (superficial) vascular segments.