The compensatory ‘rebound’ of reactive astrogliosis: glial fibrillary acidic protein immunohistochemical analysis of reactive astrogliosis after a puncture wound to the brain of rats with portocaval anastomosis

Summary This study was designed to compare the degree of reactive astrogliosis occurring around a puncture wound in the brain of normal rats and at different intervals after a similar puncture wound in rats with a portocaval anastomosis. The gliosis was evaluated by the number of astrocytes, the thickness of their processes and the intensity of the glial fibrillary acidic protein immunoreactivity. After the puncture wound in the brain of rats with a portocaval anastomosis, the gliosis varied at different intervals being: (1) decreased at 10 days, (2) markedly increased at 5 weeks and (3) significantly decreased at 8, 12, and 16 weeks. These findings suggest that 5 weeks after portocaval anastomosis, an active proliferation of the metabolically altered astrocytes occurs with heightened synthesis of glial fibrillary acidic protein in the period of adaptive compensation, the so-called compensatory rebound. At 8 weeks or more after portocaval anastomosis, these altered astrocytes were considered to be in the phase of decompensation and incapable of maintaining the reactive response which occurred in normal rats. The compensatory rebound and decompensatory decline illustrate the dynamic plasticity of the reactive astrogliosis.Supported by grant from the National Foundation of Natural Sciences No. 386-0956. This paper was read at the XIth International Congress of Neuropathology, September 7, 1990 in Kyoto, Japan     

FLT3-TKD mutation in childhood acute myeloid leukemia.

Mutations of receptor tyrosine kinases are implicated in the constitutive activation and development of human hematologic malignancies. An internal tandem duplication (ITD) of the juxtamembrane domain-coding sequence of the FLT3 gene (FLT3-ITD) is found in 20-25% of adult acute myeloid leukemia (AML) and at a lower frequency in childhood AML. FLT3-ITD is associated with leukocytosis and a poor prognosis, especially in patients with normal karyotype. Recently, there have been three reports on point mutations at codon 835 of the FLT3 gene (D835 mutations) in adult AML. These mutations are located in the activation loop of the second tyrosine kinase domain (TKD) of FLT3 (FLT3-TKD). The clinical and prognostic relevance of the TKD mutations is less clear. To the best of our knowledge, there has been no report to describe FLT3-TKD mutations in childhood AML. In this pediatric series, FLT3-TKD mutations occurred in three of 91 patients (3.3%), an incidence significantly lower than that of FLT3-ITD (14 of 91 patients, 15.4%) in the same cohort of patients. None of them had both FLT3-TKD and FLT3-ITD mutations. Sequence analysis showed one each of D835 Y, D835 V, and D835 H. Of the three patients carrying FLT3-TKD, two had AML-M3 with one each of L- and V-type PML-RARalpha, and another one had AML-M2 with AML1-ETO. None of our patients with FLT3-TKD had leukocytosis at diagnosis. At bone marrow relapse, one of the four patients examined acquired FLT3-ITD mutation and none gained FLT3-TKD mutation.     

Auditing paediatric diabetes care and the impact of a specialist nurse trained in paediatric diabetes

AIMS: To define outcome measures for auditing the clinical care of children and adolescents with insulin dependent diabetes mellitus (IDDM) and to assess the benefit of appointing a dedicated paediatric trained diabetes specialist nurse (PDSN). METHODS: Retrospective analysis of medical notes and hospital records. Glycaemic control, growth, weight gain, microvascular complications, school absence, and the proportion of children undergoing an annual clinical review and diabetes education session were assessed. The effect of the appointment of a PDSN on the frequency of hospital admission, length of inpatient stay, and outpatient attendance was evaluated. RESULTS: Children with IDDM were of normal height and grew well for three years after diagnosis, but grew suboptimally thereafter. Weight gain was above average every year after diagnosis. Glycaemic control was poor at all ages with only 16% of children having an acceptable glycated haemoglobin. Eighty five per cent of patients underwent a formal annual clinical review, of whom 16% had background retinopathy and 20% microalbuminuria in one or more samples. After appointing the PDSN the median length of hospital stay for newly diagnosed patients decreased from five days to one day, with 10 of 24 children not admitted. None of the latter was admitted during the next year. There was no evidence of the PDSN affecting the frequency of readmission or length of stay of children with established IDDM. Non-attendance at the outpatient clinic was reduced from a median of 19 to 10%. CONCLUSIONS: Outcome measures for evaluating the care of children with IDDM can be defined and evaluated. Specialist nursing support markedly reduces the length of hospital stay of newly diagnosed patients without sacrificing the quality of care.     

Phenotypic diversity in siblings with partial androgen insensitivity syndrome

The androgen insensitivity syndrome is a heterogeneous disorder with a wide spectrum of phenotypic abnormalities, ranging from complete female to ambiguous forms that more closely resemble males. The primary abnormality is a defective androgen receptor protein due to a mutation of the androgen receptor gene. This prevents normal androgen action and thus leads to impaired virilisation. A point mutation of the androgen receptor gene affecting two siblings with partial androgen insensitivity syndrome is described. One had cliteromegaly and labial fusion and was raised as a girl, whereas the other sibling had micropenis and penoscrotal hypospadias and was raised as a boy. Both were shown to have the arginine 840 to cysteine mutation. The phenotypic variation in this family is thus dependent on factors other than abnormalities of the androgen receptor gene alone.     

Cell cycle effects of antifolate antimetabolites: implications for cytotoxicity and cytostasis

 Purpose: Cell cycle-related events in CCRF-CEM lymphocytic leukemia cells were examined subsequent to inhibition of thymidylate synthase (TS) or GAR formyltransferase (GARFT) and prior to cell death or stasis. Methods: Cell populations were treated with the GARFT inhibitors 6R-5,10-dideazatetrahydrofolate (lometrexol) or LY309887, the TS inhibitor ZD1694, or the multitargeted antifolate LY231514. DNA content, nucleoside precursor incorporation and proliferating cell nuclear antigen (PCNA) expression as functions of drug treatment were assessed by multiparameter flow cytometry. Cellular respiration was measured by MTT analysis and apoptosis was detected by extraction of DNA fragments. Results: Cell populations treated for up to 96 h with lometrexol or LY309887 did not replicate and maintained a cell cycle distribution with distinct G₁, S and G₂/M regions. The number of S phase cells in treated populations was slightly elevated relative to control as measured by DNA content and PCNA. However, these cells were unable to incorporate 5-bromodeoxyuridine (BrdU). Throughout treatment, cells incubated with GARFT inhibitors maintained intact membranes and respired at a level comparable to untreated cells. In contrast, ZD1694 as well as LY231514, induced synchronization of the treatment population at the G₁/S interface within 12 h of drug addition. This was followed by synchronous entry of the population into S phase. After 24 h of treatment, more than 90% of the cells were capable of incorporating BrdU and stained positive for PCNA. DNA fragmentation occurred in cells treated with ZD1694 or LY231514 but not in those treated with GARFT inhibitors. In addition, the viable cells remaining after 24–48 h of treatment with ZD1694 or LY231514 were respiring at twice the level of untreated cells. Conclusion: These results demonstrate that the distinct endpoints of GARFT and TS inhibition are preceded by distinct cell cycle and metabolic alterations. Received: 1 April 1996 / Accepted: 5 September 1996     

Immunobiology of T helper cells and antigen-presenting cells in autoimmune thrombocytopenic purpura (ITP)

Autoimmune thrombocytopenic purpura (AITP) is a bleeding disease in which autoantibodies are directed against the individual's own platelets, resulting in enhanced Fc-mediated platelet destruction by macrophages in the reticuloendothelial system. Most research in AITP has focused on characterization of the autoantibodies, while little has been devoted to the cellular immune mechanisms leading to autoantibody production. This report summarizes the current state of the literature and argues that enhanced T helper cell/antigen-presenting cell interactions in patients with AITP are the primary stimulus for the development of antiplatelet autoantibody production. Understanding these events is important for eventually identifying disease-initiating platelet autoantigens and ultimately developing specific immunotherapies for AITP.     

Frequency of bitemporal independent interictal epileptiform discharges in temporal lobe epilepsy

PURPOSE: Bitemporal interictal epileptiform discharges (IEDs) occur in < or =42% of scalp EEGs in patients with temporal lobe epilepsy (TLE) studied with routine EEGs or partial analysis of long-term recordings. METHODS: Twenty-eight patients with TLE demonstrating exclusively unilateral temporal IEDs on routine EEGs underwent 24-h continuous recording. The entire record was visually inspected for epileptiform discharges. We used continuous EEG to assess the significance of long-term recording in detecting bilateral IEDs. RESULTS: Twenty-two patients had left temporal IEDs; 21 had right temporal IEDs. Seventeen (61%) patients had IEDs originating from both the right and left temporal lobes. The probability of detecting bilateral independent IEDs was correlated with the duration of continuous EEG recording. There was no correlation between the number of IEDs originating from one side and the probability of detecting independent IEDs on the other side. The frequencies of IEDs were not correlated with the length of time since onset of epilepsy. CONCLUSIONS: The findings suggest that when long-term recordings are performed, the incidence of bilateral discharges in TLE is higher than previously reported in the literature and supports the view that TLE is commonly a bilateral disease.     

Biomechanical comparison for different configurations of tension band wiring techniques in treating an olecranon fracture

BACKGROUND: The aim of this study was to compare the superiority between the newly designed modified AO tension band wiring technique and the traditional modified AO tension band wiring technique in treating an olecranon fracture. METHODS: Eight pairs of fresh cadaveric ulnae were tested biomechanically. After transverse osteotomy of the olecranon, all left ulnae were fixed by the traditional modified AO technique with two Kirschner wires inserted through the anterior ulnar cortex and all right ulnae by the new technique with two Kirschner wires inserted into the marrow cavity from the olecranon to the ulnar styloid process. All specimens were tested by the Material Testing System machine to evaluate fragment displacement and the maximal failure load. A dual linear variable displacement transducer was used to measure relative minimal displacement. RESULTS: There was no significant difference between the techniques. The maximal failure load by either technique was more than 80 kg. Even at testing failure, no Kirschner wires migrated proximally. CONCLUSION: The new technique may be applied widely to treat all olecranon fractures, because it is a technically easier and safer technique. Less than 5.5-kg loads could be permitted in daily activity postoperatively. A single tolerable loading weight should not exceed 8 kg. Kirschner wires will not migrate proximally, despite increased joint loading. Clinically, this study may confirm indirectly the hypothesis that proximal migration of Kirschner wires was mainly due to triceps traction.