M-score and wound healing assessment of two nonantibiotic topical gel treatments of active digital dermatitis lesions in dairy cattle

This open-label, randomized clinical trial with positive control compared the treatment of active digital dermatitis (DD) lesions (stages M1, M2, and M4.1) on dairy cattle hind feet with an enzyme alginogel or a copper and zinc chelate gel (coppergel). Upon recruitment (d 0), active DD lesions were cleaned, photographed, treated, and bandaged. This procedure was repeated on d 3 and d 7, with treatment and bandaging discontinued for those lesions that had transitioned to the M0, M3, or M4 stage on d 7. Day 10 was considered the end of the treatment trial, and all recruited feet were cleaned and photographed. Treatment effect of the 2 products was assessed not only using the M-score but also using general wound healing progress criteria. Improvement of M-score was defined as transition to M0, M3, or M4 stages, or to lesions with a smaller ulcerative area (e.g., M2 stage to M1 stage). Lesions with improved wound healing had at least one of the following criteria when compared with the previous observation: decreased defect size, healthier granulation tissue color (pink-red instead of purple-grayish), more regular aspect of granulation tissue surface, wound contraction, or epithelization starting from the surrounding skin. Both primary outcomes were assessed using a multivariable logistic regression analysis. Lesions treated with the enzyme alginogel had a decreased adjusted odds ratio for M-score improvement (aOR: 0.04; 95% confidence interval: 0.01-0.11). Lesions treated with the coppergel mostly transitioned to chronic lesions, whereas lesions treated with the enzyme alginogel mostly remained active lesions. The wound healing progress of almost 70% of the lesions treated with coppergel could not be scored, for the greater part due to the presence of crust materials. With these unscorable lesions classified as "improved," there was no treatment effect on wound healing progress (aOR: 0.99; 95% confidence interval: 0.34-3.05), whereas with unscorable lesions classified as "not improved," the enzyme alginogel outperformed the coppergel with regard to wound healing progress (aOR: 2.48; 95% confidence interval: 1.07-5.79). None of the products used in our study achieved high cure rates (transition to the M0 stage) for active DD lesions. Low cure rates of topical treatment of DD, together with the important role of chronic lesions in the epidemiology of DD, indicate that future research should investigate how to achieve successful wound management of DD lesions, thereby mitigating pain associated with the lesions and reducing both transmission and prevalence of DD within herds.

Combined versus single treatment regimens for keloid therapy using serial intralesional corticosteroid injections, surgical excision, silicone- and/or cryotherapy

Efficacy comparison of several regimens in treating keloids as combined or standalone therapies could provide essential information for selecting appropriate therapy. This study retrospectively evaluated the treatment efficacy of corticosteroid injections, excision, silicone, cryotherapy, or combinations of these for treating keloids. Additionally, the use of corticosteroid injection schemes and combined cryotherapy regimens were analysed.

Retrospective chart analysis was performed on 204 keloids treated patients at the plastic surgery department of the Máxima Medical Centre between 2009 and 2018. The patient's age, gender, treatment, anatomic location, scar aetiology, previous therapy, scar recurrence, additional therapy, and follow-up duration were retrieved. Treatment efficacy was assessed through treatment failure, defined by the recurrence or lack of response. Kaplan–Meier and Cox survival analyses were performed to compare treatment efficacy between the different regimens.

Monotherapies exhibited a significantly higher chance of treatment failure (HR 2.4, 95% CI 1.4–4.2, p<0.05) when compared to combined therapies.

Sporadic corticosteroid injections demonstrated more treatment failure overall (HR 3.5 95% CI 1,6–7,3; p=0.001), but did not differ significantly from injection schemes.

Combined cryotherapy efficacy did not differ significantly from the other combined regimens (HR 1,6 95% CI 0,5–5,1; p=0.401).

Combined therapies exhibited clear superiority over monotherapies. Sporadic corticosteroid injections demonstrated inferior results compared to all other therapies. Combined cryotherapy cases were insufficient, and more data are required for proper assessment. Future prospective assessments of corticosteroid injection schemes and combined regimens are warranted.

Usefulness of language and memory testing during intracarotid amobarbital testing: observations from an fMRI study

BACKGROUND

Several procedures for testing language lateralization and memory function exist during the intracarotid amobarbital test (IAT). The use of functional magnetic resonance imaging (fMRI) gives the opportunity to assess the validity of some of these procedures, or at least to inspect the neuronal correlates. A comprehensive fMRI protocol was tested, aimed at addressing aspects of lateralization of language, as well as testing memory in relation to activation of mesiotemporal regions. Here we report observations with possible consequences for the current IAT procedures.

MATERIALS AND METHODS

The protocol consisted of three language tasks (overt naming, semantic decision and silent word generation) and two memory tasks (encoding and retrieving visual scenes). The paradigms used a block-related procedure in nine right-handed normal volunteers. During the procedure dynamic weighted full brain images were acquired which are sensitive to the blood oxygenation activation effect.

RESULTS

Encoding showed symmetrical bilateral activation in the mesiotemporal regions, specifically the hippocampus, parahippocampal gyrus and fusiform gyrus. With a retrieval task activation of the mesiotemporal areas was restricted to the posterior hippocampal area. Overt object naming showed results, similar to encoding tasks with bilateral activation of hippocampal areas. Silent word generation showed much stronger ability to lateralize than the other two language-related tasks and especially object naming.

CONCLUSION

Activation revealed by fMRI activation shows that IAT procedures, using active semantic language processing or comprehensive procedures with multiple language tasks have the highest guarantee for individual activation lateralization. Simple object naming does not guarantee a lateralized language fMRI activation pattern. Of the different memory procedures during IAT, the procedures (Interview and the Montreal) demanding encoding processing will be related to larger areas of bilateral hippocampal activation than procedures (Seattle) exclusively requiring retrieval. Moreover, tasks using recognition of previously presented language items (naming objects) are equally effective for assessing hippocampal activation compared with presenting separate memory items.

Long-term effects of 24-month treatment with vagus nerve stimulation on behaviour in children with Lennox-Gastaut syndrome

The long-term effects of vagus nerve stimulation (VNS) on behaviour were studied in 19 children with Lennox-Gastaut syndrome. We used the following stimulation parameters: output current: 112 to 2mA; signal frequency: 30Hz frequency; signal pulse width: 500&mgr;s; signal 'on and off' time: 30s 'on,' 3min 'off.' The test battery consisted of cognitive tests assessing mental age and quality of life measurements assessing independency, behavioural problems, and mood. The results show relatively small changes in the behavioural outcomes, concurrent with the modest effects of VNS on seizure frequency (an average of 20.6% seizure reduction). When baseline measurements are compared with the follow-up measures, neither the cognitive measure nor the quality of life measures show any deterioration and the cognitive measure (mental age) showed mild positive changes (gain of 4.2 months mental age during the follow-up period). None of the changes were statistically significant. Treatment effect was most prominent in the group with the highest mental age at baseline, which suggests that mental retardation is a negative prognostic factor for VNS treatment. Moreover, in this specific patient group, treatment effect did not increase with treatment duration. Some evidence during follow-up suggests a direct positive effect of VNS on behavioural function, independent of changes in seizure frequency. Long-term treatment with VNS is not associated with adverse behavioural effects. Mental retardation is a negative prognostic factor for the efficacy of VNS.

Developing a comprehensive presurgical functional MRI protocol for patients with intractable temporal lobe epilepsy: a pilot study

Our aim was to put together and test a comprehensive functional MRI (fMRI) protocol which could compete with the intracarotid amytal (IAT) or Wada test for the localisation of language and memory function in patients with intractable temporal lobe epilepsy. The protocol was designed to be performed in under 1 h on a standard 1.5 tesla imager. We used five paradigms to test nine healthy right-handed subjects: complex scene-encoding, picture-naming, reading, word-generation and semantic-decision tasks. The combination of these tasks generated two activation maps related to memory in the mesial temporal lobes, and three language-related maps of activation in a major part of the known language network. The functional maps from the encoding and naming tasks showed typical and symmetrical posterior mesial temporal lobe activation related to memory in all subjects. Only four of nine subjects also showed symmetrical anterior hippocampal activation. Language lateralisation was best with the word generation and reading paradigms and proved possible in all subjects. The reading paradigm enables localisation of language function in the left anterior temporal pole and middle temporal gyrus, areas typically resected during epilepsy surgery. The combined results of this comprehensive f MRI protocol are adequate for a comparative study with the IAT in patients with epilepsy being assessed for surgery.

Patient and occupational dose in neurointerventional procedures

Neurointerventional procedures can involve very high doses of radiation to the patient. Our purpose was to quantify the exposure of patients and workers during such procedures, and to use the data for optimisation. We monitored the coiling of 27 aneurysms, and embolisation of four arteriovenous malformations. We measured entrance doses at the skull of the patient using thermoluminescent dosemeters. An observer logged the dose-area product (DAP), fluoroscopy time and characteristics of the digital angiographic and fluoroscopic projections. We also measured entrance doses to the workers at the glabella, neck, arms, hands and legs. The highest patient entrance dose was 2.3 Gy, the average maximum entrance dose 0.9+/-0.5 Gy. The effective dose to the patient was estimated as 14.0+/-8.1 mSv. Other average values were: DAP 228+/-131 Gy cm(2), fluoroscopy time 34.8+/-12.6 min, number of angiographic series 19.3+/-9.4 and number of frames 267+/-143. The highest operator entrance dose was observed on the left leg (235+/-174 microGy). The effective dose to the operator, wearing a 0.35 mm lead equivalent apron, was 6.7+/-4.6 microSv. Thus, even the highest patient entrance dose was in the lower part of the range in which nonstochastic effects might arise. Nevertheless, we are trying to reduce patient exposure by optimising machine settings and clinical protocols, and by informing the operator when the total DAP reaches a defined threshold. The contribution of neurointerventional procedures to occupational dose was very small.

Catheter-related epidural abscesses -- don't wait for neurological deficits

Epidural abscess is a rare but serious complication of epidural anesthesia for peri- and postoperative analgesia. It is feared because of possible persistent neurological deficits. Epidural abscess presents mostly with a classic triad of symptoms: back pain, fever and variable neurological signs and symptoms. When neurologic signs or symptoms develop, MRI scanning is the diagnostic procedure of choice. The therapy of choice is intravenous antibiotics for more than 4 weeks with or without a laminectomy or drainage. In the present paper we describe three patients with epidural abscesses presented during a time period of 1 year in our hospital. In each case, patients developed local signs of infection and systemic signs, but no neurological symptoms. Based on these cases and a review of the literature, we propose that MRI scanning should be strongly considered when patients present with systemic and local signs, even in the absence of neurological deficits.

Effects of 6 months of treatment with vagus nerve stimulation on behavior in children with lennox-gastaut syndrome in an open clinical and nonrandomized study

The effect of vagus nerve stimulation (VNS) on behavior outcomes was studied in 16 children with Lennox-Gastaut syndrome. We used the following stimulation parameters: output current, 11 2 to 2 mA; signal frequency, 30 Hz; signal pulse width, 500 microseconds; signal on and off times, 30 seconds on and 3 minutes off. The test battery consisted of cognitive tests measuring mental age, attention, language, psychomotor function, and cognitive style, and quality-of-life measurements assessing independence, behavioral problems, symptoms of pervasive development disorders (PDDs) and mood. The results show relatively small changes in behavioral outcomes concurrently with modest effects on seizure frequency (an average of 26.9% seizure reduction). When baseline and endpoint measurements are compared none of the cognitive measures show any deterioration and three of five cognitive measures show slight positive changes. Among the quality-of-life measures, one measure showed a slight worsening of scores and three showed slight improvement. When the group is divided into subgroups on the basis of treatment effect the most prominent improvements are observed in the group without any effects of VNS on seizure frequency. These patients gained, on average, 9.5 months in mental age and showed more independent behavior, mood improvements and fewer PDD symptoms. This suggests an effect of VNS on behavioral function independent of changes in seizure frequency.

CT study of craniovertebral rotation in whiplash injury

The present study investigates the diagnostic value of rotatory computed tomography (CT) examinations in normal subjects and patients with whiplash associated disorders (WAD), with the aim of reproducing earlier findings of rotatory CT studies. Forty-seven WAD patients with persistent complaints after a rear-end collision (non-cranial contact acceleration/deceleration trauma) were enrolled in this study. To guarantee a maximally homogeneous study population, only WAD patients with a marked passive cervical retroflexion restriction were included. Transversal CT slices in left and right rotation were made for all cervical levels (the skull included). CT slices in neutral position were used to reconstruct partially depicted vertebrae. Absolute rotatory values were estimated according the method of Penning and Dvorak. For all levels the relative rotatory (RR) value was calculated by dividing absolute rotation values of a particular cervical level by the corresponding total cervical rotation. The measuring error was estimated by comparing the findings of two separately performed measuring procedures. Two age groups of WAD patients were formed. A younger group was matched for age with 26 normal healthy volunteers (the original data of an earlier study). The use of neutral CT slices for reconstruction of a partially depicted cervical vertebra resulted in a measurement error of 1.9 degrees at the level of C0/C1 (occiput/atlas) and 3.5 degrees at C1/C2. Suspected hypermobility as defined by Dvorak was rare in our WAD patients (6.4% C0/C1 and 10.6% C1/C2). RR values at C0/C1 were significantly larger in 79% of the WAD patients. Discriminant analysis of the RR values showed 80% correctly classified WAD patients. Only 11.5% of the normal subjects were classified as false-positive. Since no hypermobility was found at C1/C2, a traumatic lesion of the alar ligaments is less likely. It was concluded that the use of absolute rotation values in rotatory CT scan procedures has a low diagnostic value in WAD patients. Excessive RR values were only found at C0/C1. A traumatic lesion of the ligaments at C0/C1, which prevent vertical translation of the skull with regard to the atlas, is hypothesised. The results of the discriminant analysis of the RR values make this method applicable for the individual WAD patient in daily practice.

Helmet versus nonhelmet treatment in nonsynostotic positional posterior plagiocephaly

A total of 105 infants with nonsynostotic posterior plagiocephaly were treated using a helmet or by head positioning. Effect of treatment was scored using a cosmetic outcome score (0-10 points) assigned by the parents. The onset of the observed skull deformity correction was not different for the helmet vs. nonhelmet treatment. Improvement was significantly better and faster in the helmet group compared with nonhelmet treatment (p < 0.01 and p < 0.001, respectively).

A controlled study of temporal lobe structure volumes and P300 responses in schizophrenic patients with persistent auditory hallucinations

Recent studies of cerebral pathology in patients with schizophrenia have focused on symptomatological and electrophysiological correlates of reduced temporal lobe structure volumes. Volume deficits of the left superior temporal gyrus have been correlated with auditory hallucinations as well as to left-sided P300 amplitude reduction. However, caution is needed to interpret correlational data as evidence of a specific relationship. Therefore, a controlled study was undertaken on schizophrenic patients with and without auditory hallucinations. MRI-defined volumes of the left superior temporal gyrus and other temporal lobe structures were quantified from 3-mm coronal slices in 15 schizophrenic patients with chronic auditory hallucinations (hallucinators), 15 schizophrenic patients without auditory hallucinations (nonhallucinators) and 17 healthy controls. In all subjects a simple oddball paradigm was used to elicit P300 responses at temporal and centro-parietal electrode sites. No evidence was found for volume reductions of temporal lobe structures in the combined patient group compared with controls, or in the hallucinators compared with the nonhallucinators. The patients did show left P300 amplitude reduction compared with controls, particularly in the hallucinator group. Correlations between volumes of left temporal lobe structures and left P300 amplitudes were low and not significant. The results of the present study do not indicate that auditory hallucinations and associated abnormal electrophysiological activity are the consequence of atrophy of localized temporal lobe structures. However, replication in a larger sample of subjects is needed before firm conclusions can be drawn.

The value of skull radiography in patients with head trauma

This study assesses the value of skull X-ray after a skull fracture for predicting intracranial hematoma. Patients with a skull injury were divided into three risk groups, based on the history and examination findings. The records of 1218 patients were studied. In the risk group, the existence of a skull fracture and the development of intracranial hematoma were determined. Not a single hematoma was found in the low-risk group. Hence, skull radiography had no significance in this group. In the moderate-risk group two patients had an intracranial hematoma; one patient had a skull fracture. Negative skull radiography therefore did not fully exclude intracranial complications. There were many patients with an intracranial hematoma in the high-risk group, in the presence or not of a skull fracture. CT imaging is the best method for obtaining the diagnosis of intracranial hematoma in this group. In conclusion, plain skull X-rays are of little value in patients with acute head trauma.

Isolated hemiataxia after supratentorial brain infarction

Acute isolated hemiataxia is in most cases due to infratentorial (cerebellar) stroke. It has only twice been described in supratentorial stroke--namely, after thalamic infarction and a capsular haemorrhage. Three patients with isolated hemiataxia after a supratentorial brain infarct are described. These patients were seen in a period of five years during which 899 patients with a first supratentorial brain infarct were registered. Clinically the hemiataxia was of the cerebellar type. In two patients, CT and MRI showed a small, deep (lacunar) infarct restricted to the posterior limb of the internal capsule, a site not previously reported in isolated hemiataxia. The third patient had a small, deep (lacunar) infarct in the thalamus extending into the adjacent posterior limb of the internal capsule. Isolated hemiataxia after a supratentorial brain infarct is a very rare clinical stroke syndrome. The cerebellar type hemiataxia was most likely caused by interruption of the cerebellar pathways at the level of the internal capsule. Our cases confirm prior observations that the cerebellar pathways run through the posterior part of the posterior limb of the internal capsule separately from the motor and sensory pathways.

Lysines 72, 80 and 213 and aspartic acid 210 of the Lactococcus lactis LacR repressor are involved in the response to the inducer tagatose-6-phosphate leading to induction of lac operon expression

Site-directed mutagenesis of the Lactococcus lactis lacR gene was performed to identify residues in the LacR repressor that are involved in the induction of lacABCDFEGX operon expression by tagatose-6-phosphate. A putative inducer binding domain located near the C-terminus was previously postulated based on homology studies with the Escherichia coli DeoR family of repressors, which all have a phosphorylated sugar as inducer. Residues within this domain and lysine residues that are charge conserved in the DeoR family were changed into alanine or arginine. The production of the LacR mutants K72A, K80A, K80R, D210A, K213A and K213R in the LacR-deficient L.lactis strain NZ3015 resulted in repressed phospho-beta-galactosidase (LacG) activities and decreased growth rates on lactose. Gel mobility shift assays showed that the complex between a DNA fragment carrying the lac operators and LacR mutants K72A, K80A, K213A and D210A did not dissociate in the presence of tagatose-6-phosphate, in contrast to wild type LacR. Other mutations (K62A/K63A, K72R, K73A, K73R, T212A, F214R, R216R and R216K) exhibited no gross effects on inducer response. The results strongly suggest that the lysines at positions 72, 80 and 213 and aspartic acid at position 210 are involved in the induction of lac operon expression by tagatose-6-phosphate.

Impaired fibrinolysis in cyclosporine-treated renal transplant patients. Analysis of the defect and beneficial effect of fish-oil

Cyclosporine treatment has been associated with thrombotic vascular complications. We investigated the activity of the fibrinolytic system and its capacity to respond upon DDAVP stimulation in a group of 20 cyclosporine-treated patients as compared with a group of 9 azathioprine-treated patients. Furthermore, the effect of the administration of fish-oil to these patients on the endogenous fibrinolytic activity was studied in a double-blind randomized, placebo-controlled cross-over study. The cyclosporine-treated patients showed a significantly reduced plasminogen activator activity and plasmin generation response upon the infusion of DDAVP as compared with the azathioprine group. In the cyclosporine group 60% of the patients had an impaired fibrinolytic response, whereas this was found in only 11% of the azathioprine-treated patients (P < 0.05). The impairment of the endogenous fibrinolysis activity could be attributed either to a defective release of plasminogen activator from the vessel wall (67% of patients) or to high plasma levels of plasminogen activator inhibitor 1 (33% of patients). Administration of fish-oil resulted in a significant improvement of the impaired fibrinolysis in the cyclosporine group. Particularly, in patients with a defective release of plasminogen activator from the vessel wall, fish-oil treatment resulted in a normalization of the fibrinolytic activity. These results indicate that cyclosporine treatment induces an impaired fibrinolysis that may contribute to the frequent occurrence of thromboembolic complications and eventually the impairment of renal function in cyclosporine-treated patients. The beneficial effect of the administration of fish-oil on the endogenous fibrinolysis may result in a reduction of the adverse events associated with cyclosporine treatment.

[Is skull radiography indicated in patients with head injuries?]

The value of the radiographic finding of a skull fracture in predicting intracranial haematoma is assessed in this study. Patients with a skull injury can be divided into three risk groups, based on the history and examination findings. The low-risk group includes patients who are asymptomatic or have scalp haematoma, lacerations, headache or dizziness. The moderate-risk group includes patients who have posttraumatic amnesia and/or alcohol intoxication and those who are suspected of having a skull fracture. The patients in the high-risk group have clear symptoms and signs such as depressed level of consciousness or focal neurological signs. The records of 1218 patients were studied. The risk group, the existence of a skull fracture and development of intracranial haematoma were determined. Not a single haematoma was found in the low-risk group. Therefore skull radiography had no significance in this group. In the moderate-risk group two patients had an intracranial haematoma, of whom one patient had a skull fracture. Negative skull radiography therefore did not fully exclude intracranial complications. There were many patients with an intracranial haematoma in the high-risk group, both in the presence and the absence of a skull fracture. CT scanning is the best method of detecting an intracranial haematoma in this group.

Functional significance of the morphology and micromechanics of collagen fibres in relation to partial rupture of the superficial digital flexor tendon in racehorses

The high incidence of partial rupture of the superficial digital flexor tendor in the equine athlete represents a major cause for concern in the racing industry. Frequently, the lesion is localised to the central core of the tendon. This study tested the hypothesis that the site specific structural failure results from differences in the collagen fibre morphology and associated micromechanics between central and peripheral regions of the tendon. Bundles of collagen fibres were dissected from central and peripheral sites in the mid-metacarpal region of the tendon. Crimp morphology was quantified by polarised light microscopy and mechanical characteristics determined using a fibre tensometer. In older horses, centrally located fibres showed significantly lower values for crimp angle, crimp length and toe limit strain than seen peripherally. There were no significant differences in these features between corresponding sites in the younger horses. No significant difference between sites was found in elastic modulus in either group. These data indicate a non-uniform functional stress distribution which may result from ageing or be related to the exercise history as a feature of accumulated damage. These observations may explain the location of central core lesions seen on clinical examination.

X-linked hydrocephalus

We report on a family with X-linked hydrocephalus: progressive increase in head circumference (OFC) led to the diagnosis in 3 patients; however, in 5 with normal OFC, the initial diagnosis had been "nonspecific" mental retardation, until identification of relatedness between 3 macrocephalic boys suggested segregation of a major Mendelian gene. Moderate to severe hydrocephaly was present in all macrocephalic patients and in 3 of the 5 with normal OFC, but CT-scan of the brain did not show aqueductal stenosis in any of them. We stress the importance of a brain CT-scan in every male with "nonspecific" mental retardation, especially in cases with X-linked inheritance, because confirmation of X-linkage has important genetic counseling consequences.

HLA regulates postrenal transplant CML nonreactivity

Previous studies have shown that lymphocytes from renal allografted patients with a good functioning graft display donor-specific cell-mediated lympholysis nonreactivity (CML-NR) in vitro. To define whether the HLA system influences the occurrence of the CML-NR, immunogenetic studies were carried out. Posttransplant lymphocytes derived from CML-NR patients were stimulated in vitro with lymphocytes from unrelated healthy blood donors, who were selected for the presence or absence of kidney donor-specific HLA antigens. The presentation of kidney donor-specific HLA-B (and -C) antigens on the lymphocytes of unrelated blood donors resulted in cytolytic nonresponsiveness, whereas presentation of the kidney donor-specific HLA-A locus antigens on lymphocytes of the unrelated blood donors revealed no cytolytic nonresponsiveness. The results, as displayed by posttransplant lymphocytes of renal allografted patients, demonstrate that the kidney donor HLA-B (and -C) antigens are responsible for the in vitro-observed, donor-specific CML-NR. Consequently, presentation of cells from panel members matched to the kidney donor at the HLA-B locus suppresses the response towards HLA-A locus antigens. The in vitro-observed cytolytic nonresponsiveness appeared not to be due to an absence of specific cytotoxic T lymphocytes, because the nonresponsiveness can be abrogated by addition of exogenous IL 2.

HLA regulates postrenal transplant CML nonreactivity

Previous studies have shown that lymphocytes from renal allografted patients with a good functioning graft display donor-specific cell-mediated lympholysis nonreactivity (CML-NR) in vitro. To define whether the HLA system influences the occurrence of the CML-NR, immunogenetic studies were carried out. Posttransplant lymphocytes derived from CML-NR patients were stimulated in vitro with lymphocytes from unrelated healthy blood donors, who were selected for the presence or absence of kidney donor-specific HLA antigens. The presentation of kidney donor-specific HLA-B (and -C) antigens on the lymphocytes of unrelated blood donors resulted in cytolytic nonresponsiveness, whereas presentation of the kidney donor-specific HLA-A locus antigens on lymphocytes of the unrelated blood donors revealed no cytolytic nonresponsiveness. The results, as displayed by posttransplant lymphocytes of renal allografted patients, demonstrate that the kidney donor HLA-B (and -C) antigens are responsible for the in vitro-observed, donor-specific CML-NR. Consequently, presentation of cells from panel members matched to the kidney donor at the HLA-B locus suppresses the response towards HLA-A locus antigens. The in vitro-observed cytolytic nonresponsiveness appeared not to be due to an absence of specific cytotoxic T lymphocytes, because the nonresponsiveness can be abrogated by addition of exogenous IL 2.

Interpretation of nuclear magnetic resonance tomograms of the brain

Nuclear magnetic resonance tomography is an imaging method based on the magnetic resonance behavior of protons, as they occur predominantly in tissue water or in fatty acids. This behavior, as characterized by the relaxation times T1 and T2, is determined by the chemical and physical environment of the protons. The relaxation properties of the tissue can be accentuated by selection of the appropriate pulse sequence. Interpretation of the images requires an understanding of the principles of the technique with which the relaxation times are expressed in the images, and acquaintance with the composition of the tissue in terms of relaxation properties (as in computerized tomography, tissue composition is expressed as attenuation coefficients).