Fulminant myasthenia gravis manifested after removal of anterior mediastinal tumor

Myasthenia gravis developed in a 35-year-old man after removal of an encapsulated anterior mediastinal tumor that was preoperatively diagnosed as a teratoma based on a computed tomographic image. Postoperative pathologic diagnosis of the excised tumor was thymoma. The patient was in crisis after the initiation of immunosuppressive treatment. The therapy was changed to immunoadsorbent perfusion therapy because of concurrent severe pneumonia and an extremely high serum concentration of anti-acetylcholine receptor antibodies. Respiratory support was necessary for 2 months after reoperation.     

Optimization of thin-foil based phosphor screens for CCD imaging in TEM in the voltage range of 80-400 kV

The voltage dependence characteristics of thin-foil based phosphor screens in the thickness range of approximately 10-60 microns are examined for CCD imaging in transmission electron microscopy (TEM) in the voltage range of 80-400 kV. The brightest screen is obtained with a P20 layer of about 12 microns at 80 kV, and a thicker screen lowers both the screen brightness and resolution. The thickness of the brightest screen is higher at higher voltage, but other considerations for a practical CCD imaging system suggest that the P20 layer should not be greater than approximately 18 microns for the voltage range stated above.     

Kinetics and mechanism of an NADPH-dependent succinic semialdehyde reductase from bovine brain

An NADPH-dependent succinic semialdehyde reductase has been purified from bovine brain by several chromatographic procedures. The preparation appeared homogeneous on SDS/PAGE. The enzyme is a monomeric protein with a molecular mass of 28 kDa. A number of properties of the bovine brain enzyme, such as substrate specificity, specific activity, molecular mass, optimum pH, amino acid composition, and kinetic parameters, have been determined and compared with those reported for preparations from other sources. The results indicate that the enzyme isolated from bovine brain in the present study is different from those reported for preparations from other sources. The inhibition kinetic patterns obtained when the products of the reaction or substrate analogs are used as inhibitor of the reaction catalyzed by the enzyme are consistent with an ordered sequential mechanism involving the formation of an intermediate ternary complex and in which NADPH is the first substrate to bind the enzyme.     

Immunohistoselective sequencing (IHSS) of p53 tumor suppressor gene in human oesophageal precancerous lesions

Accumulation of p53 protein occurs in human oesophageal precancerous lesions and even in near-normal oesophageal epithelium. In some instances, p53 gene mutations have been detected. In many of the cases of p53 protein accumulation in early lesions, however, p53 mutations were not detected due to either the lack of mutation or the low abundance of cells with a mutation. In order to enrich p53 immunostain-positive cells for single strand conformation polymorphism (SSCP) analysis and DNA sequencing, an immunohisto-selective sequencing (IHSS) method was developed. Anti-p53 antibody-peroxidase stained oesophageal tissue sections were subjected to ultraviolet (UV) irradiation to damage the DNA in p53 immunostain-negative cells. The immunostain protected p53 immunostain-positive cells from the UV light and thus preserved the DNA in those cells for PCR amplification. Comparison of the SSCP results from sections with and without UV treatment showed that the IHSS method selectively enriched p53 immunostain-positive cells. With this method, we could analyse mutations in samples with as few as 30 p53 immunostain-positive cells per tissue section. Analysis was carried out on tissues with precancerous lesions from six surgically-resected oesophageal specimens and 13 oesophageal biopsies from symptom-free subjects. The results of mutation analysis for some of the samples were confirmed by microdissection to enrich the p53-positive cells. The mutations in tissues with precancerous lesions were compared with those in the corresponding squamous cell carcinomas. The IHSS method is shown to be a simple and effective way to analyse mutations in p53 immunostain-positive cells. IHSS may also be a general method for molecular analysis of biological specimens after immunohistochemical staining.     

Proton MR spectroscopy after acute central nervous system injury: outcome prediction in neonates, infants, and children

PURPOSE: To evaluate the usefulness of proton magnetic resonance (MR) spectroscopy in predicting 6-12-month neurologic outcome in children after central nervous system injuries. MATERIALS AND METHODS: Localized single-voxel, 20-msec-echo-time MR spectra (including N-acetylaspartate [NAA], choline [Ch], creatine and phosphocreatine [Cr]) were obtained in the occipital gray matter in 82 patients and 24 control patients. Patient age groups were defined as neonates (< or = 1 month [n = 23]), infants (1-18 months [n = 31]), and children (> or = 18 months [n = 28]). Metabolite ratios and the presence of lactate were determined. Linear discriminant analysis-with admission clinical data, proton MR spectroscopy findings, and MR imaging score (three-point scale based on severity of structural neuroimaging changes)-was performed to help predict outcome in each patient. Findings were then compared with the actual 6-12-month outcome assigned by a pediatric neurologist. RESULTS: Outcome on the basis of proton MR spectroscopy findings combined with clinical data and MR imaging score was predicted correctly in 91% of neonates and in 100% of infants and children. Outcome on the basis of clinical data and MR imaging score alone was 83% in neonates, 84% in infants, and 93% in children. The presence of lactate was significantly higher in patients with poor outcome than in patients with good-moderate outcomes in all three age groups (neonates, 38% vs 5%; infants, 87% vs 5%; children, 64% vs 10% [chi 2 test, P < .02]). In children with poor outcomes, NAA/Cr ratios were significantly lower in infants (P = .006) and children (P < .001), and NAA/Ch ratios were significantly lower in infants (P = .001) and neonates (P = .05). CONCLUSION: Findings at proton MR spectroscopy helped predict long-term neurologic outcomes in children after central nervous system injury.     

The relationship between serum and saliva erythropoietin concentrations in adults, full-term and premature infants

Not only thyroid adenomas and carcinomas, but also the majority of single and well delimited goiter nodules, even if morphologically heterogeneous, are of clonal origin. However, it is still unknown whether the nodules of rapidly growing, recurrent goiters are clonal or polyclonal. We investigated by PCR-based analysis of exon 1 of the human androgen receptor gene clonality of nodules grown in recurrent multinodular goiters (MNG) of 14 female patients. The total goiter volume varied widely between 15 ml and 170 ml. The mean age of patients undergoing surgery for recurrent goiter at the time of their first operation was significantly lower with 34.6 +/- 10.9 yr in comparison to 50 consecutive patients who were operated for MNG for the first time (53.7 +/- 13.5 yr). The interval between first and recurrent operation was 18 +/- 8.5 yr. The mean volume of well circumscribed nodules selected for the present investigation was 3.8 +/- 1.4 ml. Assessment of clonality in at least 2 samples of each lesion revealed a polyclonal pattern in 10 out of 14 nodules, whereas only 3 nodules were clonal and in one case the result remained unclear. The unexpected finding that most nodules within MNG, that had re-grown after a first subtotal thyroidectomy, were of polyclonal rather than clonal composition, suggests that these lesions are generated by de novo-proliferation of cohorts of differing thyrocytes sharing the common trait of an exceedingly high intrinsic growth rate or alternatively, by unknown growth stimulating molecular events acting focally on clusters of cells derived from different ancestors. In addition, the relatively young age of patients with recurrent MNG at the time of their first surgery and the comparatively short interval between first and second operation point to a genetic element in the occurrence of growth-prone thyrocytes.     

One-stage versus two-stage Soave pull-through for Hirschsprung's disease in the first year of life

Several investigators have reported good results after a one-stage Soave procedure without a stoma for infants with Hirschsprung's disease. The authors reviewed their concurrent experience with the one- and two-stage approaches, comparing the two groups with respect to rate of complications and clinical outcome. Over a 3-year period, 36 infants with colonic Hirschsprung's disease presenting in the first year of life were treated with a Soave pull-through. Thirteen had a one-stage pull-through, and 23 had a two-stage procedure using an initial stoma. There was no difference with respect to median age at time of diagnosis, median follow-up period, length of aganglionosis, or male:female ratio between the groups. The incidences of major complications such as small bowel obstruction, segmental or acquired aganglionosis, anastomotic leak, and malabsorption were equal between the two groups. However, 13% of the two-stage patients required revision of the stoma. All major complications in the one-stage group were in those who weighed less than 4 kg at the time of surgery. Minor complications such as wound infection, perianal excoriation, and need for repeated dilatation were similar between the groups, but minor stoma-related complications (prolapse or retraction) occurred in 26% of the two-stage infants. When complications were stratified using a more sophisticated scale of severity, no significant difference was found between the groups. The overall complication rate was 1.5 events per patient in the one-stage group and 2.0 events per patient in the two-stage group. This small difference was related to the presence of a stoma in the two-stage group. Overall, 10 of 12 survivors in the one-stage group and 22 of 23 in the two-stage group were doing well, with normal bowel function noted on long-term follow-up (mean period, of 14 and 19 months, respectively). Both one- and two-stage approaches were associated with a significant complication rate, although long-term outcome was excellent in both groups. The higher complication rate in the two-stage group was attributable to the presence of a stoma. For small infants, it may be beneficial to delay the one-stage pull-through until weight exceeds 4 kg.