Biomedical subjects
J Pyhtinen
Publications and source records attributed to J Pyhtinen.
Dopamine transporters increase in human brain after alcohol withdrawal.
Dopaminergic transmission has been suggested to be a main mechanism mediating reinforcement, withdrawal and craving associated with alcohol addiction. We measured here striatal dopamine (DA) transporter binding from 27 alcoholics within 4 days after cessation of prolonged heavy drinking and after a 4-week period of abstinence with single photon emission computed tomography (SPECT) using a cocaine analogue, iodine-123-beta-CIT. Controls were 29 healthy volunteers. Blind quantitative analyses of the SPECT data revealed markedly lower DA transporter binding in alcoholics on admission for detoxification than in the non-alcoholic controls. After a 4-week period of abstinence DA transporter binding increased significantly in the alcoholics (P<0.0001) reaching the levels of the healthy controls. The most substantial recovery in DA transporter binding occurred during the first 4 days of abstinence. The data indicate that prolonged heavy drinking decreases DA transporter binding and disturbs synaptic dopamine transport. This may sensitize alcoholics to dopaminergic transmission, which may lead to early relapse after ethanol withdrawal.
A longitudinal magnetic resonance imaging study of the brain in survivors in childhood acute lymphoblastic leukemia.
BACKGROUND: The objective of this study was to evaluate changes in magnetic resonance imaging (MRI) of the brain in children with acute lymphoblastic leukemia (ALL) during the first 5 years after the cessation of therapy and to correlate MRI abnormalities with neuropsychologic outcome. METHODS: Thirty-two children with ALL were studied at the end of treatment and 5 years later by brain MRI and the results were compared with the neuropsychologic findings. Fifteen patients had received chemotherapy alone and 17 had received chemotherapy plus cranial radiation. RESULTS: MRI of the brain was abnormal in 6 of 30 patients at the end of treatment and in 8 of 32 patients 5 years later. White matter changes (WMC) were found in 3 patients at the end of treatment and in 4 patients 5 years later. Two patients had developed new mild changes, whereas in one case WMC had normalized during the follow-up. Two patients had old hemorrhages or calcifications at each examination, with some improvement after follow-up, although one case revealed a new calcification or hemorrhage. Signs of cortical atrophy were observed in five patients at both evaluations. The patients with abnormal MRI findings did not differ significantly in their performance in the neuropsychologic tests from the patients with normal MRI findings, but the two patients with persistent WMC had a depression of verbal functions. CONCLUSIONS: Abnormalities in brain MRI were infrequent at the end of treatment for childhood ALL and 5 years later. They did not appear to correlate significantly with neuropsychologic outcome. Brain MRI is not very informative as a routine follow-up method during the first 5 years after treatment.
Intracranial arterial dissection.
We review the angiographic and CT findings, precipitating factors and clinical features in nine patients with ten intracranial arterial dissections. The internal carotid artery was involved in five cases, the vertebral artery in four and the posterior inferior cerebellar artery in one. Angiography revealed irregular stenosis in four cases, irregular stenosis and a pseudoaneurysm in two, irregular stenosis and irregular dilatation in one, arterial occlusion in two and a pseudoaneurysm in one. CT demonstrated an infarct in four cases, a dense middle cerebral artery in two and subarachnoid haemorrhage in one. A possible precipitating factor was identified in five cases. Six patients recovered well, while three had persisting neurological deficits.
The helical three-dimensional CT in the diagnosis of torticollis with occipitocondylar hypoplasia.
Congenital anomalies of the atlanto-occipital and atlantoaxial joints are rare. Those most commonly reported are atlantoaxial instability, basilar impression, anomalies of the odontoid process, laxity of the transverse atlantal ligament and atlanto-occipital fusion. Occipital condylar hypoplasia is infrequent and difficult to recognise. We recently diagnosed it using helical 3D CT in association with torticollis in two patients. The first patient had a several year history of torticollis. The second patient had acute cervical lymphadenitis associated with post-operative torticollis. 3D CT distinctly revealed atlantoaxial subluxation with hypoplasia of the occipital condyles in both cases.
Densities and sizes of main masticatory muscles in patients with internal derangements of temporomandibular joint obtained by computed tomography.
Computed tomography (CT), due to its excellent resolution capacity, is a suitable method to examine the soft and bony structures of the masticatory system. The aim of this study was to compare densities and sizes of the masseter and medial and lateral pterygoid muscles obtained by CT between the symptomatic and asymptomatic side in patients with internal derangement of the temporomandibular joint (TMJ). The aim was also to correlate these variables to sex and age, duration of the symptoms, diagnosis and dentition. The material consisted of 33 patients (26 women, 7 men, mean age 37 years, range 14-74 years) whose TMJs were examined by CT and whose coronal CT scans were available. Diagnosis in the symptomatic TMJ was confirmed in operation. No statistically significant difference was seen in mean densities and sizes of the masticatory muscles between the symptomatic and asymptomatic side. The duration of the symptoms, however, correlated positively to the density of the lateral pterygoid muscles in patients with complete dentition. The age of the patients in this group correlated negatively to the size of the masseter muscles. It can be concluded that patients with internal derangements of TMJ with a long duration of symptoms have structural changes in their masticatory muscles which are detectable by CT.
Effect of edentulousness on mandibular size and condyle-fossa position.
Modern imaging methods make possible the more precise examination of the complicated bony structure of the temporomandibular joint (TMJ) and the performance of cephalometric analysis. The aim of our study was to analyse the effect of edentulousness on the mandibular size and the condyle-fossa position using roentgencephalograms and axial computed tomography (CT) scans. The study group consisted of 20 edentulous patients (14 women, six men, mean age 60 years) whose mean period of edentulousness was 20 years (range 3-34 years). A CT examination of their TMJs was performed and roentgen-cephalograms in 16 of this group were taken after prosthetic treatment. Sixteen dental students were chosen according to sex as controls. Earlier CT scans of 49 dentate subjects of both sexes were used as controls for the analysis of bicondylar asymmetry. The position of the glenoid fossa was more anterior in edentulous subjects than in dentate ones and its anterior position correlated significantly (P < 0.02) with the period of edentulousness, a finding which has not been confirmed before. It can be concluded that the fossa is a remodelling unit as a part of the functional entity when the function is altered dramatically as in the case of edentulous patients.
Psychological findings in preterm children related to neurologic status and magnetic resonance imaging.
OBJECTIVE: Preterm children experience learning disabilities more often than full-term children, but detailed information on their neuropsychological and neurologic determinants is lacking. We therefore examined these problems more closely and also studied if clinical neurologic examination and/or magnetic resonance imaging (MRI) can be used as tools to screen the preterm children at risk for these problems. METHODS: In a population-based study, the psychological performance of 42 preterm children with a birth weight <1750 g and of their matched controls was assessed at 8 years of age and the findings were then related to clinical neurologic examination and MRI. Learning disabilities of these children, reported by the teachers, were also studied. RESULTS: The cognitive ability of the preterm children, although in the normal range, was significantly lower than that of the control children. They performed particularly poorly in tasks requiring spatial and visuoperceptual abilities, which were associated with the finding of periventricular leukomalacia in MRI, especially with posterior ventricular enlargement. The preterm children with minor neurodevelopmental dysfunction (MND) had the most problems in neuropsychological tests, whereas the clinically healthy preterm children and those with cerebral palsy had fewer problems. The problems of MND children emerged in the domain of attention. They also experienced the most problems at school. CONCLUSIONS: Visuospatial problems were associated with periventricular leukomalacia in MRI, but learning disabilities were most frequent among the preterm children with minor neurologic abnormalities. We recommend closer follow-up of preterm children with MND.
Magnetic resonance imaging of periventricular leukomalacia and its clinical correlation in children.
The prevalence of periventricular leukomalacia and its association with clinical neurological signs in school-age preterm children are unknown. We matched 42 eight-year-old children who were born before term with birth weights lower than 1,750 gm (mean, 1,410 gm; gestational age, 31 weeks) with 42 children who were born at term and of normal birth weight, to compare clinical neurological status and magnetic resonance imaging findings. Of the children born prematurely, 9.5% had cerebral palsy and 31% had minor neurological dysfunction whereas 9% of the children born at term had minor neurological dysfunction and none had cerebral palsy. Deviations in tongue movements, heel walking. Fogs test results, and finger opposition, as well as behavioral disturbances, differentiated the preterm from the full-teem group. The prevalence of periventricular leukomalacia among all children born prematurely was 32%. It was observed in all children with cerebral palsy, in 25% with minor neurological dysfunction, and in 25% of the clinically healthy preterm children. None of the children born at term had evidence of periventricular leukomalacia. Children with periventricular leukomalacia especially demonstrated poor performance on heel walking and Fogs test. Though commonly found in preterm children, periventricular leukomalacia is not uniformly associated with abnormal neurological findings. A thorough neurological examination is a better predictor of later developmental problems than is magnetic resonance imaging.
Cerebral abscess with multiple rims of MRI.
We present a patient with multiple brain abscesses caused by Nocardia asteroides. On T2-weighted MRI, multiple concentric rims were seen in the abscess, which could be a finding specific for infection. The rims may be due to organization of the necrotic debris and phagocytoses by macrophages in the capsule.
Brain perfusion after treatment of childhood acute lymphoblastic leukemia.
UNLABELLED: Children with acute lymphoblastic leukemia (ALL) have impairment in their neuropsychological functioning and morphological changes in their brain after cranial irradiation and chemotherapy. The aim of this study was to identify possible brain perfusion defects caused by different types of treatment and their association with abnormalities in cerebral MRI and neuropsychological and clinical neurological findings. METHODS: Twenty-five consecutive children with ALL at the cessation of chemotherapy or after 1 yr were included. All of the children were given intravenous and intrathecal methotrexate for central nervous system therapy, 13 of them received cranial radiation therapy. Brain SPECT, cerebral MRI, clinical neurological and neuropsychological evaluations were performed. RESULTS: Eleven of the 25 patients (44%) had brain perfusion defects in SPECT, eight of whom were treated with chemotherapy alone, and three received cranial irradiation. Two patients had small bilateral white matter changes on MRI; their brain SPECT scans were abnormal, although the findings were not related. Impairment of neuropsychological functioning was found in 86% of the patients tested. No significant difference between the patients with abnormal and normal SPECT were found. Those patients with abnormal SPECT were younger than those with normal SPECT and had received more frequent intravenous methotrexate infusions. CONCLUSION: Brain SPECT detected perfusion defects that had occurred after treatment for childhood ALL. These defects may be related to frequent administration of a combination of intravenous and intrathecal methotrexate and/or young age.
Influence of antineoplastic therapy on function of the masticatory system, tooth development, and cariogenic status: a case report.
Antineoplastic therapy causes developmental disturbances in the dental enamel and root if children are treated during tooth development. Increased caries activity has also been reported. The effect of anticancer therapy on the function of the masticatory system (i.e. jaws, dentition, masticatory muscles) is not well known. A case report of a 9-year-old girl with right auricular rhabdomyosarcoma is presented. She received irradiation of 50 Gy to the right auricular area and chemotherapy. A year and a half after cessation of cancer therapy, she was disease free and the clinical stomatognathic examination combined with electromyogram (EMG) registration of the masseter and temporal muscles and magnetic resonance imaging (MRI) examination of the temporomandibular joints (TMJ) revealed a strongly restricted mouth opening capacity, painful right TMJ, and flattened head of the right mandibular condyle. Muscle atrophy in the right masseter muscle was clearly visible but EMG activities of the masseter and temporal muscles, however, were higher on the right than on the left. More severe developmental defects, and worse gingival and cariological health were observed on the right side than on the left side. She developed 12 carious lesions and all the lesions were on the right maxilla or mandible or on anterior teeth. The left side was not affected. Intensive prophylactic dental care after cancer treatment is important in order to prevent caries and gingival inflammation. Stomatognathic treatment (i.e. management of occlusal and dysfunctional problems) may improve the mouth opening capacity and relieve pain.
Minor changes on cranial MRI during treatment in children with acute lymphoblastic leukaemia.
Cranial MRI was used to study treatment-related changes in children undergoing therapy for acute lymphoblastic leukaemia (ALL) or lymphoma. Nineteen children (18 with ALL, 1 with lymphoma) underwent MRI at the beginning of treatment and at intervals during it, to a total of 105 imaging studies and a minimum of 3 per case. Nine patients had finished all therapy, all received consolidation treatment. No patient had central nervous system (CNS) leukaemia at diagnosis or developed a CNS relapse. Mild treatment-related white matter changes were observed in only 2 patients after consolidation therapy with three 5 g/m2 pulses of intravenous methotrexate. Transient enlargement of the ventricles and cortical sulci was observed in 13 patients, always temporally related to steroid treatment. These preliminary data suggest that treatment-related white matter changes are rare and no routine MRI follow-up is needed during treatment in asymptomatic children after a baseline assessment.
Imaging in optic nerve coloboma.
Explore the source record for details and available documents.
A difficult diagnosis of gliomatosis cerebri.
Gliomatosis cerebri, a rare condition, requires clinical, radiological and pathological correlation for diagnosis. Mental and personality changes are the most common presenting symptoms with or without focal neurological signs. The widespread nature of the disease is revealed by CT or MRI. The shape of the brain may be maintained and pathological gross examination may be unremarkable or show hypertrophy without evident tumour. Microscopic examination reveals infiltration of the brain by variably differentiated neoplastic glial cells. We present a patient with gliomatosis cerebri in whom we experienced difficulties with diagnosis. The literature is reviewed and the diagnostic features summarised.
Chronic encapsulated intracerebral haematomas.
We present four patients with uncommon encapsulated intracerebral haematomas (ICH). Because of ring enhancement, three were incorrectly diagnosed as gliomas and operated upon. In one case the diagnosis of chronic ICH was made on MRI. MRI can be used to demonstrate that a lesion is only a haematoma and is valuable in follow-up and in differentiating these haematomas from neoplasms. Angiography may reveal a vascular malformation which may be the reason for repeated bleeding, which may lead to encapsulation. The mechanism, however, remains unclear in most cases.
Increase of blood NAD+ and attenuation of lactacidemia during nicotinamide treatment of a patient with the MELAS syndrome.
Decreased activity of complex I (NAD:ubiquinone oxidoreductase) is the most frequent biochemical finding associated with mutation at the base pair 3243 of the mitochondrial DNA. The mutation has been previously shown to lead to a defective translation. We hypothesized that due to an imperfect assembly of complex I subunits the substrate affinity of this enzyme may be lowered and this may be counteracted by increasing the mitochondrial NAD+NADH concentration. Therefore, we studied the effect and mechanism of action of nicotinamide treatment in a MELAS patient with the base pair 3243 mutation. Nicotinamide treatment was initiated after his first stroke-like episode. The blood NAD concentration (representing the intracellular concentration in erythrocytes) increased linearly being 24-fold at 6 weeks of treatment. Blood lactate and pyruvate concentration decreased by 50% within three days and 24 h urine lactate content within 2 weeks and we observed a clinical improvement together with a decrease in the lesion volume in magnetic resonance imaging within the first month. The cellular NAD increase upon nicotinamide administration was probably universal, because it occurred in a time and dose-dependent manner in cultured fibroblasts from both the patient and the controls. Alleviation of the lactate accumulation during the nicotinamide treatment suggests that an increase in the cellular NAD+NADH concentration leads to enhancement of the oxidation of reducing equivalents. However, the Km of complex I for NADH in skeletal muscle from the patient was similar to that of controls. This may indicate that physiologically mitochondrial complex I operates at non-saturating substrate concentration, and this may explain the effect of nicotinamide treatment.
Clinical and computed tomographic findings in costochondral grafts replacing the mandibular condyle.
PURPOSE: The aim of this study was to evaluate by computed tomography (CT) and clinically the structure and function of costochondral grafts (CCG) used to replace the mandibular condyles. MATERIAL AND METHODS: CT and clinical examination were performed in 11 patients with CCGs (9 female, 2 male; mean age at surgery, 25 years; range, 9 to 44 years) approximately 4.5 years after surgery (range, 5 months to 10.5 years). One mandibular condyle was replaced in six patients and two in five patients. RESULTS: Facial asymmetry was observed in two cases and palpation tenderness of the TMJs or clicking and crepitation were found in 10 of 16 operated TMJs. In three cases coronal CT scans showed the graft to be situated laterally in the mandibular fossa, and lateral overgrowth of the graft was seen in three cases. In two cases, coronal CT slices showed that a new fossa had developed. In most cases translatory movement of the graft was minimal. The graft was either partially or almost completely mineralized, especially in cases with longer follow-up. CONCLUSIONS: Most of the patients in this study seemed to have benefitted from replacement of the deformed mandibular condyle with a CCG as estimated by improved range of mandibular movements and decreased symptoms. There were some problems related to unpredictable growth and location of the graft, as well as restricted movement of the replaced condyle. In the future, care should be taken to ensure proper postoperative functional therapy and to examine the role of cartilage thickness on future growth in young patients.