Tonsil cryptolysis usingCO2 Swiftlase

Treatment for inflammation of the tonsils has taken a variety of therapeutic forms over the years, ranging from the application of iodine and massage in the preantibiotic era to the tonsillectomy, which prevails today. The architecture of the cryptic tonsil, its clinical implications, and the rationale for a conservative, yet effective treatment modality focusing on the tonsillar crypts are addressed in this article. Also described are the procedures and results of a retrospective clinical study in which conventional tonsillectomy was compared with CO₂ SwiftLase cryptolysis. Although our observations are not based on a prospective, controlled study, the information disseminated here may be useful to otolaryngologists who routinely perform tonsillectomy in their practice, using conventional surgical dissection methods or the CO₂ laser. According to our experience with a population of 120 patients, cryptolysis offers some clear advantages, particularly when performed with the SwiftLase apparatus. The procedure can be performed safely in an ambulatory surgery or office setting under local anesthesia. The cooperative patient avoids the cost and risks of general anesthesia. Limited tissue destruction significantly reduces operative and postoperative complications, discomfort, and recovery time. To conclude, CO₂ SwiftLase cryptolysis is a safe and cost-effective method of treating tonsil pathology without unnecessary sacrifice of the organ, and undue risks and expenses to the patient.^11,12     

Cellular and molecular characteristics of an immortalized ataxia-telangiectasia (group AB) cell line

Ataxia-telangiectasia (A-T) is a multisystem hereditary disease featuring neurodegeneration, immunodeficiency, extreme cancer proneness, chromosomal instability, and radiosensitivity. A-T is found in many ethnic groups, and is genetically heterogeneous: four complementation groups have been identified in A-T so far. Attempts to isolate the A-T gene are based in part on gene transfer experiments, using permanent A-T fibroblast lines, obtained by transformation with SV40. "Immortalization" of A-T primary diploid fibroblasts using SV40 is difficult, possibly because of the chromosomal instability of these cells. The number of currently available permanent A-T fibroblast lines is small, and not all of them have been assigned to specific complementation groups. Using the assay of X-ray induced inhibition of DNA synthesis, we have assigned the A-T strain AT22IJE to complementation group AB. Origin-defective SV40 was used to transfect these cells, and one transformant (AT22IJE-T), which survived crisis, was found to have the typical characteristics of permanent cell lines obtained in this way. "In-gel renaturation" analysis did not show any DNA amplification of high degree in AT22IJE-T. Cytogenetic analysis showed considerable chromosomal instability in the new cell line, and medium conditioned by these cells contained the clastogenic activity which is characteristic of the parental strain as well. Other parameters of the "cellular A-T phenotype" have also been retained in the immortalized cells: hypersensitivity to the lethal effects of X-rays and neocarzinostatin, as well as "radioresistant" DNA synthesis. However, the sensitivity of AT22IJE-T to both DNA-damaging agents is less pronounced than that of the parental cells. The capacity of the cells for uptake of foreign DNA was tested by introducing into them the plasmid pRSVneo, using three different transfection methods. Satisfactory frequency of G418-resistant transfectants (0.66%) was achieved using a protocol recently published by Chen and Okayama (Mol. Cell Biol., 7: 2745-2752, 1987), which was found to be superior to the traditional calcium phosphate transfection method and to the polybrene-based method.     

The value of sperm pooling and cryopreservation in patients with transient azoospermia or severe oligoasthenoteratozoospermia.

BACKGROUND: A transient state of azoospermia may occur due to toxic, environmental, infectious or iatrogenic conditions. Finding sperm in the ejaculate of such patients is often unpredictable and may be critical in IVF treatment. In the present study, the approach of pooling and cryopreservation of sperm is evaluated. Cryopreservation was performed in a unique group of patients in whom no sperm had been found in at least one previous sperm examination and in patients diagnosed as suffering from non-obstructive azoospermia in whom, occasionally, sperm were found. METHODS: A total of 157 semen pooling and cryopreservation procedures in 53 patients was performed between January 1998 and December 2000 in our centre. Forty five of these patients underwent an IVF-ICSI treatment during the study period. In 32 patients, fresh sperm were used to perform ICSI. In 13 patients no sperm were available, and the previously frozen sperm were used. RESULTS: Using our pooling system, 13 IVF-ICSI cycles were rescued. In seven patients with a previous testicular biopsy due to azoospermia, sperm cryopreservation was possible. Overall, 13 pregnancies (10 deliveries, two ongoing pregnancies and one missed abortion) were achieved. CONCLUSION: The introduction of semen banking for patients with transient azoospermia may increase the chance of pregnancy using their own sperm.     

Defective potassium currents in ataxia telangiectasia fibroblasts

Similarities exist between the progressive cerebellar ataxia in ataxia telangiectasia (AT) patients and a number of neurodegenerative diseases in both mouse and man involving specific mutations in ion channels and/or ion channel activity. These relationships led us to investigate the possibility of defective ion channel activity in AT cells. We examined changes in the membrane potential of AT fibroblasts in response to extracellular cation addition and found that the ability of AT fibroblasts to depolarize in response to increasing concentrations of extracellular K⁺ is significantly reduced when compared with control fibroblasts. Electrophysiological measurements performed with a number of AT cell lines, as well as two matched sets of primary AT fibroblast cultures, reveal that outward rectifier K⁺ currents are largely absent in AT fibroblasts in comparison with control cells. These K⁺ current defects can be corrected in AT fibroblasts transfected with the full-length ATM cDNA. These data implicate, for the first time, a role for ATM in the regulation of K⁺ channel activity and membrane potential.     

The complete sequence of the coding region of the ATM gene reveals similarity to cell cycle regulators in different species

Ataxia-telangiectasia (A-T) is an autosomal recessive disorderinvolving cerebellar degeneration, immunodeficiency, radiationsensitivity, and cancer predisposition. A-T heterozygotes aremoderately cancer prone. The A-T gene, designated ATM, was recentlyidentified in our laboratory by positional cloning, and a partialcDNA clone was found to encode a polypeptide with a PI-3 kinasedomain. We report here the molecular cloning of a cDNA contigspanning the complete open reading frame of the ATM gene. Thepredicted protein of 3056 amino acids shows significant sequencesimilarities to several large proteins in yeast, Drosophilaand mammals, all of which share the PI-3 kinase domain. Manyof these proteins are involved in the detection of DNA damageand the control of cell cycle progression. Mutations in theirgenes confer a variety of phenotypes with features similar tothose observed in human A-T cells. The complete sequence ofthe ATM gene product provides useful clues to the function ofthis protein, and furthers understanding of the pleiotropicnature of the A-T mutations.     

Predominance of null mutations in ataxia-telangiectasia

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency, chromosomal instability, radiosensitivity and cancer predisposition. The responsible gene, ATM, was recently identified by positional cloning and found to encode a putative 350 kDa protein with a Pl 3-kinase-like domain, presumably involved in mediating cell cycle arrest in response to radiation-induced DNA damage. The nature and location of A-T mutations should provide insight into the function of the ATM protein and the molecular basis of this pleiotropic disease. Of 44 A-T mutations identified by us to date, 39 (89%) are expected to inactivate the ATM protein by truncating it, by abolishing correct initiation or termination of translation, or by deleting large segments. Additional mutations are four smaller in-frame deletions and insertions, and one substitution of a highly conserved amino acid at the Pl 3-kinase domain. The emerging profile of mutations causing A-T is thus dominated by those expected to completely inactivate the ATM protein. ATM mutations with milder effects may result in phenotypes related, but not identical, to A-T.      

Duchenne muscular dystrophy and idiopathic hyperCKemia segregating in a family

A 7-month-old boy with gross motor delay and failure to thrive presented with rhabdomyolysis following an acute asthmatic episode. During hospitalization an electrocardiographic conversion to a Wolff-Parkinson-White type 1 (WPW) pattern took place. Duchenne muscular dystrophy (DMD) was suspected based on elevated creatine kinase (CK) serum levels, muscle biopsy, and family history. The diagnosis was confirmed by molecular analysis, which documented a deletion corresponding to cDNA probe 1-2a in the dystrophin gene, in the propositus and in an affected male cousin of his mother. “Idiopathic” hyperCKemia was found in the propositus, his father, and 5 of his relatives. We suggest that the unusually early and severe manifestations of DMD in this patient may be related to the coincidental inheritance of the maternal DMD gene and of a paternal gene, causing hyperCKemia. © 1995 Wiley-Liss, Inc.     

Neurological Manifestations of COVID-19 Feature T Cell Exhaustion and Dedifferentiated Monocytes in Cerebrospinal Fluid

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