High-dose methamphetamine treatment alters presynaptic GABA and glutamate immunoreactivity

The goal of this study was to determine if high-dose methamphetamine treatment altered presynaptic immunoreactivity for the amino acid neurotransmitters GABA and glutamate within the basal ganglia. Methamphetamine (15 mg/kg every 6 h, four doses) treatment in rats resulted in severe hyperthermia and a long-lasting (four weeks) depletion of striatal dopamine content (>80%). Severe dopamine loss correlated with a decrease in the density of presynaptic immunolabeling for GABA one week post-drug, and an increase after four weeks. Although no changes were seen in presynaptic striatal glutamate immunoreactivity, there was a significant increase in the percentage of glutamate-immuno-positive terminals associated with perforated postsynaptic densities. Rats given the same dose of methamphetamine but prevented from becoming hyperthermic showed less severe dopamine depletions and a lack of ultrastructural or immunocytochemical changes. In addition, induction of hyperthermia in the absence of drug decreased immunolabeling within mitochondria, but had no effect on dopamine content, morphology or nerve terminal immunoreactivity. Altered presynaptic GABA immunolabeling and terminal size were found in both the striatum and globus pallidus, suggesting that dynamic changes occur in the striatopallidal pathway following methamphetamine-induced dopamine loss. In addition, ultrastructural changes in glutamate-positive synapses which have been correlated with increased synaptic activity were found. These results are similar to changes in GABA and glutamate synapses that follow nigrostriatal dopamine loss in 6-hydroxydopamine-lesioned animals and in Parkinson's disease, and provide the first direct evidence that methamphetamine-induced dopamine loss alters the GABAergic striatopallidal pathway. Exposure to either methamphetamine or prolonged hyperpyrexia decreased mitochondrial Immunoreactivity, indicating that hyperthermia may contribute to methamphetamine toxicity by affecting energy stores.     

Repair of coarctation of the aorta in children: postoperative morphology

To determine the morphologic sequelae after surgical repair of coarctation of the aorta, the authors retrospectively reviewed angiograms and hemodynamic and clinical data on 215 patients who underwent cardiac catheterization after surgical repair of coarctation of the aorta during a 13-year period. Ninety-seven patients (45%) underwent coarctation resection with end-to-end anastomosis; 92 (43%), subclavian-flap angioplasties; and 26 (12%), synthetic-patch repairs. Sixty-four patients (30%) had an "aneurysm," defined as a measurement ratio of repair site to diaphragmatic aorta greater than 1.5. Transverse-arch or isthmic hypoplasia or recoarctation was detected in 86 patients (40%) and was most commonly associated with septal defects or obstruction of the left ventricular outflow tract. Pullback systolic pressure gradients at catheterization were significantly higher (P = .0001) in the patients with transverse-arch hypoplasia and recoarctation than in those with ratios of transverse arch to diaphragmatic aorta greater than 0.9. Significant postoperative arch obstructions can be predicted with measurement ratios on the basis of the diameter of the abdominal aorta.     

A comparison of some robust eigenvalue assignment techniques

Three techniques for robust eigenvalue assignment are presented. The first is well known and is based on iteratively assigning the closed-loop eigenvectors so as to be maximally orthogonal to one another. The second has been recently presented by the authors and is an improvement of the first which gives better results for problems where complex-conjugate eigenvalue pairs are to be assigned. The final method is new and is founded on the iterative replacement of the current closed-loop eigenvector matrix with a new matrix which is the projection of the columns of the nearest orthogonal matrix into the allowable eigenvector subspaces. Some numerical examples are given which are used to illustrate the improved results obtained using the second technique in place of the first and to compare these with the performance of the last algorithm which is based on an alternative approach.     

Preoperative Factors of Endometrial Carcinoma in Patients Undergoing Hysterectomy for Atypical Endometrial Hyperplasia

ObjectiveTo identify clinicopathological preoperative factors associated with concurrent endometrial carcinoma in patients undergoing surgical management of atypical endometrial hyperplasia.MethodsThe records of all patients who underwent hysterectomy for preoperatively diagnosed atypical endometrial hyperplasia at a tertiary care hospital from April 2017 to April 2020 were retrospectively reviewed. Clinicopathological characteristics of patients were extracted. Patients who did not undergo hysterectomy or who had evidence of simple hyperplasia or carcinoma on initial biopsy were excluded. Univariate analysis was performed. A multivariate regression model for progression to endometrial carcinoma was developed.ResultsA total of 126 patients were included. Of these patients, 19 (15.1%) had a final diagnosis of endometrial carcinoma, whereas 86 (68.2%) retained the diagnosis of atypical endometrial hyperplasia and 21 (16.7%) were found to have no residual atypical endometrial hyperplasia. The odds of a patient being diagnosed with endometrial carcinoma were 6.1 times higher (95% CI 1.32–27.68) if they had an endometrial stripe thickness >1.1 cm and 13.5 times higher (95% CI 3.56–51.1) if there was histological suspicion of carcinoma. The odds of a patient being diagnosed with endometrial carcinoma were significantly lower if the patient had an initial diagnosis of atypical endometrial hyperplasia in a polyp (OR 0.07; 95% CI 0.02–0.34).ConclusionOur results suggest that an endometrial stripe thickness >1.1 cm, a histological suspicion of carcinoma on preoperative pathology, and the absence of polyp involvement on initial diagnosis are the strongest predictors of endometrial carcinoma at the time of hysterectomy in patients with atypical endometrial hyperplasia.     

Rapidly Involuting Congenital Hemangioma: Clinical and Histopathologic Features

We define the histopathologic findings and review the clinical and radiologic characteristics of rapidly involuting congenital hemangioma (RICH). The features of RICH are compared to the equally uncommon noninvoluting congenital hemangioma (NICH) and common infantile hemangioma. RICH and NICH had many similarities, such as appearance, location, size, and sex distribution. The obvious differences in behavior served to differentiate RICH, NICH, and common infantile hemangioma. Magnetic resonance imaging (MRI) of the three tumors is quite similar, but some RICH also had areas of inhomogeneity and larger flow voids on MRI and arterial aneurysms on angiography. The histologic appearance of RICH differed from NICH and common infantile hemangioma, but some overlap was noted among the three lesions. RICH was composed of small-to-large lobules of capillaries with moderately plump endothelial cells and pericytes; the lobules were surrounded by abundant fibrous tissue. One-half of the specimens had a central involuting zone(s) characterized by lobular loss, fibrous tissue, and draining channels that were often large and abnormal. Ancillary features commonly found were hemosiderin, thrombosis, cyst formation, focal calcification, and extramedullary hematopoiesis. With one exception, endothelial cells in RICH (as in NICH) did not express glucose transporter-1 protein, as does common infantile hemangioma. One RICH exhibited 50% postnatal involution during the 1st year, stopped regressing, was resected at 18 months, and was histologically indistinguishable from NICH. In addition, several RICH, resected in early infancy, also had some histologic features suggestive of NICH. Furthermore, NICH removed early (2–4 years), showed some histologic findings of RICH or were indistinguishable from RICH. We conclude that RICH, NICH, and common infantile hemangioma have overlapping clinical and pathologic features. These observations support the hypothesis that these vascular tumors may be variations of a single entity ab initio. It is unknown whether the progenitor cell for these uncommon congenital vascular tumors is the same as for common infantile hemangioma. This study was presented in part at the Spanish Society of Plastic and Reconstructive Surgery Meeting, Tenerife, Spain, May 3, 2000 and the Vascular Anomalies 2001 Symposium, New York University Medical Center, New York, NY, May 18, 2001.     

Prophylactic antibiotics after urodynamics in women: a decision analysis

The objective of this paper is to compare the risks and benefits of antibiotics to prevent urinary tract infection (UTI) after urodynamics. We developed a decision analytic model to compare the use of prophylactic antibiotics with no antibiotic use after urodynamics to prevent UTI. Risks and benefits were estimated from the literature and by consensus. The main outcome measure was the occurrence of UTI. Secondary outcomes were the development of adverse events and possible sequelae. One-way sensitivity analyses estimated the effect of varying each characteristic through its range while all other characteristics were fixed at their baseline values. The effectiveness of prophylaxis after urodynamics was a reduction of UTI from 9.2 (no antibiotics) to 5.3% (antibiotics). One-way sensitivity analysis of the probability of UTI without prophylaxis yielded a threshold infection rate of 10%, below which, the strategy of no prophylaxis was favored. In this model, prophylactic antibiotics after urodynamics are not beneficial until the rate of UTI without antibiotics exceeds 10%.