Biallelic mutations in mitochondrial tryptophanyl-tRNA synthetase cause Levodopa-responsive infantile-onset Parkinsonism.

Mitochondrial aminoacyl-tRNA synthetases (mtARSs) are essential, ubiquitously expressed enzymes that covalently attach amino acids to their corresponding tRNA molecules during translation of mitochondrial genes. Deleterious variants in the mtARS genes cause a diverse array of phenotypes, many of which involve the nervous system. Moreover, distinct mutations in mtARSs often cause different clinical manifestations. Recently, the gene encoding mitochondrial tryptophanyl tRNA synthetase (WARS2) was reported to cause 2 different neurological phenotypes, a form of autosomal recessive intellectual disability and a syndrome of severe infantile-onset leukoencephalopathy. Here, we report the case of a 17-year-old boy with compound heterozygous mutations in WARS2 (p.Trp13Gly, p.Ser228Trp) who presented with infantile-onset, Levodopa-responsive Parkinsonism at the age of 2 years. Analysis of patient-derived dermal fibroblasts revealed decreased steady-state WARS2 protein and normal OXPHOS content. Muscle mitochondrial studies suggested mitochondrial proliferation without obvious respiratory chain deficiencies at the age of 9 years. This case expands the phenotypic spectrum of WARS2 deficiency and emphasizes the importance of mitochondrial protein synthesis in the pathogenesis of Parkinsonism.

Disruption of the cyclic AMP phosphodiesterase-4 (PDE4)-HSP20 complex attenuates the ß-agonist induced hypertrophic response in cardiac myocytes.

The small heat shock protein HSP20 is known to be cardioprotective during times of stress and the mechanism underlying its protective abilities depends on its phosphorylation on Ser16 by PKA (protein kinase A). Although the external stimuli that trigger Ser16 phosphorylation have been well studied, the events that modulate spatial and temporal control of this modification remain to be clarified. Here, we report that inhibition of cAMP phosphodiesterase-4 (PDE4) induces the phosphorylation of HSP20 in resting cardiac myocytes and augments its phosphorylation by PKA following ß-adrenergic stimulation. Moreover, using peptide array technology, in vitro binding studies, co-immunoprecipitation techniques and immunocytochemistry, we show that HSP20 binds directly to PDE4 within a region of the conserved catalytic domain. We also show that FRET-based, genetically-encoded cAMP reporters anchored to HSP20 exhibit a larger response to PDE4 inhibition compared to free cytosolic cAMP reporters, suggesting that the interaction with PDE4 is crucial in modulating the highly localised pool of cAMP to which HSP20 is exposed. Using information gleaned from peptide array analyses, we developed a cell-permeable peptide that serves to inhibit the interaction of PDE4 with HSP20. Disruption of the HSP20-PDE4 complex, using this peptide, suffices to induce phosphorylation of HSP20 by PKA and to protect against the hypertrophic response measured in neonatal cardiac myocytes following chronic ß-adrenergic stimulation.

Clinical use of the self-expanding metallic stent in the management of colorectal cancer.

PURPOSE: This report describes our experience with the use of self-expanding metallic stents (SEMS) in the management of obstructing colorectal cancer. METHODS: A retrospective chart review of all patients undergoing placement of SEMS between May 1997 and January 2000 was performed. RESULTS: Insertion of SEMS was attempted in 12 patients. Successful stent placement was achieved in 10 of the 12 patients. The locations of lesions were hepatic flexure (2), splenic flexure (1), left colon (1), sigmoid colon (4) and rectum (4). The intended uses of SEMS were for palliation in 3 patients and as a bridge to elective surgery in 9. In the latter group, SEMS placement allowed for preoperative bowel preparation in 4 patients and administration of neoadjuvant therapy prior to elective surgery in 2 patients. One patient died prior to definitive surgery. Stent placement was unsuccessful in 2 patients. Three SEMS-related complications occurred; 1 stent migrated and 1 stent obstructed secondary to tumor ingrowth. One patient died 13 days after stent placement and colonic decompression. CONCLUSION: SEMS represent a useful tool in the management of obstructing colorectal neoplasms. As a bridge to surgery, SEMS provide time for a complete preoperative evaluation and a mechanical bowel preparation and may obviate the need for fecal diversion or on-table lavage. It may also allow for time to administer neoadjuvant therapy when indicated. As a palliative measure, SEMS can eliminate the need for an operation.

Colorectal cancer in hereditary breast cancer kindreds.

PURPOSE: This study compared characteristics of colorectal cancer between families with dominant breast cancer inheritance and the general population. The cumulative incidence of colorectal cancer was also studied in genetically determined breast cancer syndrome subjects with BRCA1 and BRCA2 mutations and compared with the general population. METHODS: Subjects included 42 patients with colorectal cancer from 32 clinically determined hereditary breast cancer kindreds based on the autosomal dominant inheritance of breast cancers and early age of onset. The general population colorectal cancer cohort was composed of 755 patients from a tumor registry. Lifetime risk of colorectal cancer was determined in 164 BRCA1 and 88 BRCA2 gene mutation carriers and compared with the general population. Mean age of colorectal cancer onset, anatomic site distribution, histologic stage at presentation, and five year stage-stratified survival rates were compared between clinically determined hereditary breast cancer family members and the general population. RESULTS: The lifetime risk of colorectal cancer in male BRCA1 and BRCA2 mutation carriers was 5.6 percent, which was not different from 6 percent in males from the general population. Likewise, the lifetime colorectal cancer risk in female BRCA1 and BRCA2 mutation carriers was 3.2 percent, which was not different from 5.9 percent in females from the general population. Mean age of onset +/- standard error for patients with colorectal cancer was 60 +/- 2 years for hereditary breast cancer kindreds compared with 67 +/- 0.4 years for the general population (P = 0.0004). Colorectal cancer site distribution did not vary between hereditary breast cancer and the general population. Overall colorectal cancer stage distribution was significantly different, with more Stage I and fewer Stage IV cancers in subjects with hereditary breast cancer compared with the general population (P = 0.01). Overall five year stage-stratified colorectal cancer survival rate +/- standard error was 66 +/- 8 percent for hereditary breast cancer kindreds and 46 +/- 2 percent for the general population (P = 0.023). CONCLUSION: Lifetime cumulative colorectal cancer incidence in subjects with BRCA1 and BRCA2 gene mutations was not different from the general population. However, significant differences in colorectal cancer were noted between hereditary breast cancer family members and the general population. Hereditary breast cancer-associated colorectal cancer had an earlier age of onset, lower tumor stage, and better survival rate than the general population. Except for age of onset, colorectal cancer in hereditary breast cancer kindreds exhibited more favorable characteristics than colorectal cancer in the general population.

Use of preoperative ultrasound staging for treatment of rectal cancer.

INTRODUCTION: Transrectal ultrasound is the standard method for preoperative staging of rectal cancer. This study reviews the accuracy of transrectal ultrasound staging for T3 disease and its use in the selection of patients for neoadjuvant chemoradiation. METHODS: One hundred seventeen patients underwent preoperative transrectal ultrasound evaluation for rectal cancer. Accuracy of transrectal ultrasound was evaluated among 70 patients not receiving preoperative chemoradiation. Forty-seven patients received neoadjuvant chemoradiation based on transrectal ultrasound results. Tumor downstaging and early recurrence were evaluated among 45 of 47 patients receiving neoadjuvant chemoradiation. RESULTS: Among 70 nonirradiated patients, 19 were pathologic Stage pT3. Transrectal ultrasound correctly identified 18 of 19 patients with Stage pT3 (sensitivity, 94.7 percent). Transrectal ultrasound correctly identified 44 of 51 patients with less than pT3 disease (specificity, 86.3 percent). After preoperative chemoradiation in 45 patients with ultrasound Stage uT3 or uT4 tumors, 56 percent of them experienced a reduction in T stage. Residual nodal disease was found in 31 percent of patients. A complete pathologic response with no residual disease at operation was observed in 22 percent of patients. During a median follow-up period of 21 months after diagnosis, seven patients experienced a recurrence of their disease at a median of 12 months after diagnosis. Five of seven patients with recurrence were among a subgroup of ten patients who both failed to downstage T and had residual nodal disease at operation. CONCLUSION: Transrectal ultrasound is an accurate modality for selecting patients for neoadjuvant treatment. Preoperative chemoradiation produced downstaging in 56 percent of patients. Factors related to early recurrence included residual nodal disease and failure to downstage T after neoadjuvant chemoradiation.

Evaluation of monoclonal antibody-based capture enzyme immunoassays for detection of specific antibodies to measles virus.

Monoclonal antibodies to the hemagglutinin protein, fusion protein, phosphoprotein, matrix protein, and nucleoprotein of measles virus were evaluated as detector antibodies in capture enzyme immunoassays (EIAs) for the detection of specific serum immunoglobulin G (IgG), IgA, and IgM antibodies to measles virus. A pool of monoclonal antibodies to hemagglutinin protein and nucleoprotein proved optimal and was further evaluated. Specific IgM was detected in 97% of adolescents with clinical measles, 97% of infants 3 weeks postvaccination, and less than 1% of normal serum specimens. Specific IgA antibodies were found in 97% of adolescents with clinical measles, 97% of infants 3 weeks postvaccination, and less than 1% of normal serum specimens. Specific IgA antibodies were found in 97% of clinical measles cases and vaccinees, in 26% of healthy persons, and in 36% of infants 8 months postvaccination; consequently, IgA antibodies were not a useful indicator of recent measles infection. A significant increase in IgG antibodies between paired specimens was detected in 92% of clinical cases and all vaccinees. Only 59% of infant specimens had persistent IgG antibodies as detected by capture EIA at 8 months postvaccination, whereas all specimens had antibodies as detected by hemagglutination inhibition and plaque neutralization. An alternative indirect EIA, in which antigen was directly absorbed to the solid phase, was more sensitive than the capture design, detecting IgG antibodies in all infants postvaccination. When standardized with a microneutralization assay for the detection of persistent antibodies, the indirect IgG EIA gave predictive values for positive and negative tests exceeding 90%. Our capture IgM and indirect IgG EIAs provide a practical combination of serologic tests for the determination of acute measles virus infection and past exposure to measles virus or vaccine, respectively.

Distribution of cytochrome P-450 monoxygenase enzymes in the nasal mucosa of hamster and rat.

Deposition of inhaled particulates onto the respiratory mucosa is relatively great in that portion of the nasal cavity unprotected by ciliated, goblet, or keratinized superficial cells. The cytochrome P-450 system is an important enzyme system involved in the biotransformation of xenobiotics into metabolites that are more readily absorbed. To examine the transitional region caudal to the nasal vestibule, nasal tissues of hamster and rat were prepared for immunocytochemistry. Blocks of tissue representing four levels along the long axis of the nasal cavity were examined. Paraffin sections were processed through the avidin-biotin peroxidase procedure, with diaminobenzidine tetrahydrochloride as the chromagen. Enzyme localization was accomplished through the use of antibodies for three rabbit cytochrome P-450 isozymes; 2, 5, and 6 (subfamilies IIB, IVB, and IA, respectively); and for rabbit NADPH-cytochrome P-450 reductase. Enzyme distribution was similar in both hamster and rat nasal tissues except in cells of striated and intercalated ducts of nasal glands and in cells of the nasolacrimal duct where immunoreactivity was greater in the hamster. Immunoreactivity for reductase and isozyme 2 was intense in nonciliated cells lining the nonolfactory epithelium, in sustentacular cells of the olfactory epithelium, and in acinar cells of olfactory glands. Distribution of reaction products to isozyme 5 and 6 were similar to but not so intense as those of reductase and isozyme 2. Reaction products for reductase and isozyme 2 occurred generally in the same cellular and intracellular regions with the following exceptions: isozyme 2 was more concentrated in cells of striated ducts and of the nasolacrimal duct, and reductase was more abundant in intercalated ducts of nasal glands.(ABSTRACT TRUNCATED AT 250 WORDS)

[Synthesis of 1-substituted nitroimidazoles and its evaluation as radiosensitizing agents]. / Síntesis de nitroimidazoles 1-sustituidos y su evaluación como radiosensibilizantes.

The synthesis of various substituted nitroimidazoles with lipophilic and hydrophilic side chains as potential radiosensitizing agents is described. The starting material employed was 4(5)-nitroimidazole, which was alkylated via the sodium salt with various chloro-methylated, substituted alcohols and esters, in order to obtain analogues of misonidazole, metronidazole and desmethylmisonidazole of known radiosensitizing and bactericidal activity. Some final products were assayed for their radiosensitizing properties giving negative results under the testing conditions used.

Structure and organization of the subepithelial microvasculature in the canine nasal mucosa.

To quantitatively characterize the epithelial microvasculature in the transitional nasal mucosa of the dog, septal, dorsal conchal, and ventral conchal tissues were prepared for light microscopy. Subsequent to the drilling of orientation holes perpendicularly into the epithelium, serial 1.0-micron sections were cut parallel to the epithelial plane. A computerized data acquisition system was used in which the sections were aligned and the lumen/wall interfaces of capillaries digitized. Information stored in the program included the position of capillaries, their diameter, their major axis length, and the angle between their major axis and the X axis of the coordinate system. The intraepithelial capillary loops constituted 9% of the epithelial volume, and had a surface area of 31.18 mm2/mm3 of epithelium, and a length of 1055 mm/mm3 of tissue. Their diameters ranged from 9.1 to 11.3 microns for the three tissues sampled. The distances between afferent and efferent limbs of capillary loops were 4.4, 4.5, and 13.8 microns for nasal septum, alar fold, and dorsal concha, respectively. Additional analyses indicated that capillary loops were neither arranged in rows nor oriented to airflow. Rather than conducting heat to the luminal surface, the primary function of these vessels may be to transport cells and/or cytokines to and from a specialized epithelium, one that is adapted to metabolizing contaminants deposited during breathing.