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Specialized scanning ion-conductance microscope for imaging of living cells.

A specialized scanning ion conductance microscope (SICM) for imaging living cells has been developed from a conventional patch-clamp apparatus, which uses a glass micropipette as the sensitive probe. In contrast with other types of scanning probe microscope, the SICM probe has significant advantages for imaging living cells: it is most suitable for imaging samples immersed in water solutions; and since the probe senses ion current and does not need physical contact with the sample during the scan, any preliminary preparation of cells (fixation or adherence to a substrate) is unnecessary. We have successfully imaged murine melanocytes in growth medium. The microscope images the highly convoluted surface structures without damaging or deforming them, and reveals the true, three-dimensional relief of the cells. This instrument has considerable ability to operate, potentially simultaneously, in applications as diverse as real-time microscopy, electrophysiology, micromanipulation and drug delivery.

Animals↗

Development of a new, highly sensitive zona pellucida binding assay using a bioluminescence-enhanced detection system.

To date, two different zona binding assays have been described in the literature. Both assays, however, require a large quantity of human zonae which vary immensely in quality. Furthermore, an inverted microscope with micromanipulation equipment is necessary, which makes both assays relatively complicated and time-consuming, and requires skilled staff. Therefore, we developed a new, highly sensitive zona binding assay using a bioluminescence-enhanced system which employs a pool of solubilized zona pellucida and is easier for routine use. In the detection system, light emission by the luciferin-luciferase system is measured. Because of the limited availability of human zonae pellucidae, this new assay was first developed in the porcine system. The new bioluminogenic substrate D-luciferin-O-beta-galactopyranoside (Lu-Gal) was synthesized, purified and characterized. Synthesis of Lu-Gal resulted in purity better than 99.998%. Analytical data and spectra were appropriate. In terms of the kinetic data, Lu-Gal is a highly sensitive and specific substrate for beta-galactosidase. Using the given chemical conditions, nonlabelled zonae bound competitively to boar spermatozoa, which resulted in a high sensitivity and specificity. By the addition of 10 nonlabelled zonae, the binding of labelled zonae was almost completely inhibited. Corresponding results were obtained when the bioluminescent system was compared with the hemizona assay. On the other hand, spermatozoa of other species (bull, hamster and man) showed only low binding to the porcine zonae or none at all. Competitive displacement was not observed, indicating the inter-species specificity of the assay.

Animals↗

Chromosomal anomalies in human gametes and pre-implantation embryos, and their potential effect on reproduction.

This paper reviews the latest data on chromosomal abnormalities in human gametes and embryos. A close relationship between such anomalies and reproduction failure in humans has been postulated, thereby underscoring the importance of ongoing studies into the mechanisms leading to anomalies. Until recently, knowledge of chromosomal anomalies in human gametes and embryos has been limited. Newly developed strategies (in vitro fertilization combined with micromanipulation techniques followed by multicolour fluorescence in situ hybridization, and PCR analyses) allow precise investigation of this problem. This review of the available information on the etiology of chromosomal anomalies indicates that some of the genetic anomalies in human gametes and early embryos result in reproductive failure.

Chromosome Aberrations↗

Phylogeny and in situ identification of a morphologically conspicuous bacterium, Candidatus Magnospira bakii, present at very low frequency in activated sludge.

A morphologically conspicuous bacterium that constituted a very small fraction (< 0.01%) of the total microbial community of activated sludge was enriched and analysed phylogenetically by a combination of cultivation-independent molecular and physical methods. The large, corkscrew-shaped, filamentous bacteria were first detected in municipal activated sludge by light microscopy owing to their unusual rotating gliding motility. Various attempts at microbiological enrichment and pure culture isolation with traditional techniques failed, as did attempts to retrieve the morphotype of interest by micromanipulation. In situ hybridization with the group-specific, rRNA-targeted oligonucleotide probe CF319a indicated a phylogenetic affiliation to the Cytophaga-Flexibacter group of the Cytophaga-Flavobacterium-Bacteroides phylum. Based on strong morphological resemblance to members of the genus Saprospira, additional 16S rRNA-targeted oligonucleotides with more narrow specificity were designed and evaluated for in situ hybridization to the morphotype of interest. Flow cytometric cell sorting based on the fluorescence conferred by probe SGR1425 and forward scatter enabled a physical enrichment of the helical coiled cells. Subsequent polymerase chain reaction (PCR) amplification of 16S rDNA fragments from whole fixed sorted cells with a primer pair based on probes CF319a and SGR1425 resulted in the retrieval of 12 almost identical partial 16S rDNA fragments with sequence similarities among each other of more than 99.2%. In situ hybridizations proved that the sequences that showed the highest similarity (88.4%) to the 16S rRNA of Saprospira grandis were indeed retrieved from the corkscrew-shaped filaments. The bacterium is likely to be a member of a genus of which no species has been cultured hitherto. It was consequently tentatively named 'Magnospira bakii' and has the taxonomic rank of Candidatus Magnospira bakii, as the ultimate taxonomic placement has to await its cultivation. In this study, it was demonstrated that even bacteria occurring at very low frequencies in highly complex environmental samples can be retrieved selectively without cultivation for further molecular analysis.

Cloning, Molecular↗

Real-time measurement of electrically evoked extracellular dopamine in the striatum of freely moving rats.

The real-time measurement of electrically evoked dopamine was established in brain extracellular fluid of freely moving rats. Dopamine was monitored by fast-scan cyclic voltammetry at carbon fiber microelectrodes lowered into the striatum by means of a detachable micromanipulator. A stimulating electrode, previously implanted in the substantia nigra, was used to evoke striatal dopamine efflux. Evoked extracellular dopamine was both current and frequency dependent. When low current intensities (+/-125 microA) and frequencies (10-20 Hz) were applied, detectable levels of dopamine were elicited without a perceptible behavioral response. Reproducible concentrations of extracellular dopamine could be evoked in the same rat for at least 2 months. These concentrations, moreover, were significantly higher in freely moving rats compared with rats anesthetized with Equithesin. Analysis of measured curves for dopamine uptake and release rates revealed that anesthesia inhibits release but does not affect uptake. It is concluded that (a) fast-scan cyclic voltammetry at carbon fiber microelectrodes is a viable technique for the measurement of electrically evoked dopamine in brain extracellular fluid of freely moving rats, (b) it is possible to determine in situ rate constants for dopamine release and uptake from these temporally and spatially resolved measurements of levels of dopamine, and (c) transient changes in extracellular dopamine levels elicited by electrical stimulation are affected by anesthesia.

Anesthesia↗

Microanatomical compartments of clonal and reactive T cells in mycosis fungoides: molecular demonstration by single cell polymerase chain reaction of T cell receptor gene rearrangements.

Mycosis fungoides (MF) is a cutaneous T cell lymphoma, clinically characterized by patches, plaques and tumors occurring in successive stages of the disease. In early MF, an infiltrate consisting of mainly reactive T cells is seen in the papillary dermis while tumor cells are mostly confined to the epidermis. By contrast, later stages show nodular infiltrates formed mostly of tumor cells in the dermis while the epidermis is relatively devoid of tumor cells; however, knowledge of the localization of clonal T cells has been based on histomorphologic features and immunohistochemical stainings visualizing certain V-beta subfamilies of the T cell receptor (TCR). As these techniques do not allow for an unequivocal identification of clonal tumor cells, we used micromanipulation and single cell PCR amplifying the TCR chain gene rearrangement. A total number of 387 single T cells was isolated from six skin biopsies in five patients in patch, plaque, and tumor stages. Of these, 180 T cells were picked from the epidermis and 207 from the dermal infiltrate. The rearranged TCR-gamma DNA could be sequenced from 181 of 387 T cells. In three of six patients representing all three stages, epidermal T cells with a clonal rearrangement could be amplified. In early plaque stage a higher degree of epidermal T lymphocytes was found than in initial patch, later plaque, and tumor stages with an inverse distribution found for reactive T lymphocytes. In two patients a biallelic rearrangement was demonstrated that had not been detected in prior PCR analysis from blood and skin samples. These data show that clonal (neoplastic) and non-clonal (reactive) T lymphocytes in MF preferentially infiltrate different microanatomical compartments of the skin, depending on the stage of disease. The microanatomically distinct localization of reactive and clonal T cells suggests that the absence of direct contact between tumor and host-defense lymphocytes may contribute to tumor persistence and progression in epidermis, peripheral blood, and deep dermal tumor cell nests, respectively.

Aged↗

High-resolution autoradiographic studies of comparative nucleologenesis and genome reactivation during early embryogenesis in pig, man and cattle.

Using high-resolution autoradiography, simultaneous studies of ultrastructure and nucleic acid dynamics were performed during nucleologenesis in early porcine, human and bovine embryos. In contrast to the early genome activation known to occur during the second cell cycle in the mouse, the onset of rRNA synthesis detected by (5-3H) uridine incorporation in the nucleolar compartment is delayed by cleavage of one cell cycle (to the third cell cycle) in the early pig embryo and by two cell cycles (to the fourth cell cycle) in human and cattle embryos. Extranucleolar RNA synthesis, as detected by nucleoplasm labelling, generally started shortly before rRNA synthesis. The timing of nucleolar labelling was well correlated with the penetration of embryonic DNA into the nucleolus precursor body and with nucleolus structure differentiation. Ultrastructural and/or autoradiographic techniques are suggested for the study of the onset of embryonic transcription, e.g. in embryos "reconstructed" by micromanipulation.

Animals↗

Fetal cells in cervical mucus and maternal blood.

Research in developing effective and accurate methods for non-invasive prenatal diagnosis has focused on two main techniques: the retrieval of trophoblast cells from the cervix and the enrichment of fetal erythroblasts from the blood of pregnant women. The isolation of fetal cells by both approaches has permitted the identification of fetal aneuploidies by the use of fluorescence in-situ hybridization (FISH) with appropriate probes, as well as fetal single gene disorders by polymerase chain reaction (PCR). In the latter instance, it has been shown that in order to attain the high degree of specificity required for prenatal diagnosis, it is necessary to analyse single fetal cells isolated by micromanipulation. This practice has permitted the successful characterization of fetal rhesus status, haemoglobinopathies, Duchenné's muscular dystrophy and spinal muscular atrophy, amongst others.Further developments include investigations into whether the diagnostic potential of fetal cells retrieved by either method can be expanded by the possible culturing of such cells, as well as the possibility of performing successive rounds of FISH and PCR by the recycling of isolated fetal cells.A novel observation that our group has made is that the traffic of fetal cells is enhanced in pregnancies affected by the pregnancy related disorder, pre-eclampsia. Our subsequent investigations have shown that this elevation in fetal cell traffic may serve as an early marker for those pregnancies at risk for this disorder.A very recent exciting discovery has been that free extracellular fetal DNA can be detected in the plasma and serum of pregnant women, which may permit the rapid and accurate detection of uniquely fetal loci, such as the fetal rhesus D gene in rhesus D negative pregnant women.

Cervix Mucus↗

Effect of acetazolamide on the optic disc oxygenation in miniature pigs.

BACKGROUND: The purpose of our study was to evaluate the variations of the optic disc PO (2) during normoxia and hyperoxia (100 % O (2)), before and after intravenous administration of acetazolamide. MATERIAL AND METHODS: PO (2) measurements were obtained at intervascular areas of the optic disc in 11 anaesthetized miniature pigs using oxygen-sensitive microelectrodes introduced through the vitreous cavity by a micromanipulator. PO (2) was measured continuously during 10 minutes under systemic normoxia and systemic hyperoxia. Oxygen measurements were repeated under these conditions after intravenous injection of acetazolamide (bolus of 500 mg) in 8 animals. RESULTS: In systemic hyperoxia, the optic disc PO (2) increased moderately (DeltaPO (2) = 4.7 +/- 2.5 mmHg; p < 0.001; n = 11) in parallel with systemic PaO (2). Acetazolamide led to a slow and progressive increase in the optic disc PO (2) (DeltaPO (2) = 2.1 +/- 1.7 mmHg; p > 0.1; n = 8 after 10 min, while DeltaPO (2) = 4.3 +/- 3.2 mmHg; p < 0.05; n = 8 after 30 min), in parallel with a slow and progressive increase in systemic PaCO (2). The optic disc PO (2) increased much more significantly after injection of acetazolamide under systemic hyperoxia (DeltaPO (2) = 13.3 +/- 3.1 mmHg; p < 0.001; n = 8). CONCLUSIONS: Systemic hyperoxia alone is not sufficient to increase substantially the optic disc PO (2) in miniature pigs due to a vasoconstrictor effect. Intravenous injection of acetazolamide can increase the optic disc PO (2) progressively, due to a vasodilatory effect of elevated systemic PaCO (2). The association of acetazolamide injection with systemic hyperoxia can further improve the oxygenation of the optic disc.

Acetazolamide↗

[Successful outcome of "intracytoplasmic sperm injection" (ICSI) within the scope of in vitro fertilization].

Poor function of spermatozoa accounts for half of all human infertility. "Intracytoplasmic sperm injection" (ICSI) is a new micromanipulatory method for the treatment of male infertility. "ICSI" was performed in cases of oligoasthenozoospermia in 12 IVF cycles, obtaining a fertilisation rate of 71.2% of all micromanipulated oocytes. So far four ongoing pregnancies occurred. Thus "Intracytoplasmic sperm Injection" represents a new encouraging technique to conceive, even in cases of severe male infertility.

Adult↗

[Partial endoscopic resections with CO2 laser in laryngeal cancer. I. Resection techniques].

The laser surgical technique as used in more than 250 laryngeal carcinomas since 1979 is described. The CO2 laser is always used as a cutting instrument and not to vaporize the tumour, since this would not enable a control of complete tumour removal. The vaporisation technique is used only in combination with the cutting technique for laser surgical debulking of large laryngeal tumours. Five cutting techniques are differentiated: 1) excisional biopsy; 2) excision of the tumour in several portions; 3) incision of large tumours for staging purposes; 4) palliative excision of primary tumours in inoperable lymph node metastases; 5) palliative reduction of large tumours (debulking). T1a vocal cord carcinomas and circumscribed carcinomas of the border of the epiglottis are resected by means of a so-called excisional biopsy. This means that the tumour is resected in toto with a small line of adjoining healthy tissue. For the removal of large carcinomas of the vocal cord, or of tumours that cross the anterior commissure, or of larger supraglottic tumours, an unusual technique is employed. The tumorous tissue is cut with the laser and resected in several fragments. This may seem to contradict current oncological principles and is only possible because of laser-specific tissue reactions. When using a modern micromanipulator (711 Acuspot, Sharplan, London; diameter of the laser beam: 0.25 mm at 400 mm working distance) at low power levels (1-2 watts) and continuous wave mode, very slight or no bleeding is caused on the surface of the dissected tissue allowing differentiation between tumour and healthy tissue with the operating microscope.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗

[Constitutional release of nitrogen monoxide (NO) by the retina of the minipig is a major determinant of arteriolar basic tonus in the internal retina].

PURPOSE: NO is a nonpolar gas, which diffuses across cell membranes in an isotropic fashion. In relatively large arteries NO has been identified as the endothelium-derived releasing factor and the current hypothesis is that NO controls the vascular tone. We are investigating an alternative hypothesis proposing that the retinal tissues surrounding the arterioles contribute in the process of NO production. METHODS: We performed flicker light stimulation in anesthetized minipigs (hypnodyl 100 mg/hr, tubocurarine 0.1 mg/hr und N2O) in steady-state of normoxia-normocapnia. An NO-microprobe mounted on a micromanipulator was introduced into the eye through the pars plana and positioned on the preretinal space in a zone free of visible vessels. Preretinal NO gradient and recording of NO release variations in response to flicker light stimulation were performed so as periarteriolar microinjections of nitro-L-arginine. RESULTS: When advancing the NO-probe from the vitreous towards the retina we recorded an NO-gradient corresponding to an efflux of 7.1 pMol x min-1 x cm-2 (N = 9). With the microprobe positioned close to the retina and after 60 min dark adaptation we recorded a mean increase in NO release of 1.59 muMol +/- 0.13 SE. After periarteriolar microinjection of nitro-Larginine we recorded a transitory reversible vasoconstriction. CONCLUSIONS: These results indicate that a process occurring in the extravascular tissue of the retina modulates the production of NO and that constitutional NO release by the retina is a major determinant of the basal retinal arteriolar tone.

Animals↗

[193 excimer laser trepanation in perforating keratoplasty. Report of 70 patients].

BACKGROUND: In penetrating keratoplasty, trephination with the 193 nm excimer laser may help avoid the differences in the deformation of the donor and recipient wound margins which occur with the conventional procedure. By varying the shape of the "open metal mask", other cut configurations can be achieved besides circular. Thus, "vertical tilt" and "horizontal torsion", both potential reasons for persistent long-term astigmatism after PK, may be minimized. Following experimental studies, the authors present the results obtained in their first 70 consecutive patients. PATIENTS AND METHODS: 38 women and 32 men were treated (mean age 60.6 years, range 17 to 89 years). Indications were corneal processes without vascularization: Fuchs' dystrophy (n = 32), other stromal dystrophies (n = 5), secondary corneal endothelial decompensation (n = 6), keratoconus (n = 15), nonvascularized corneal scars (n = 4) and miscellaneous (n = 8 ). We used elliptical metal masks with/without orientation teeth and circular masks with four and eight orientation teeth, respectively. The HeNe aiming beam was manually controlled by a micromanipulator ("joystick"). The technical data of the laser were as follows: spot mode, 1.5 x 1.5 mm; repetition rate 30/sec and 25/sec, respectively; pulse energy 15-25 mJ; mean number of pulses 6407 (recipient) and 9150 (donor). With an elliptical outline, wound closure was usually achieved with single sutures. With a circular outline with orientation teeth, wound closure was most commonly achieved with a double running suture. Patients were prospectively documented using modified Erlangen record sheets. Follow-up ranged from 3 months to 3.4 years (mean 11.4 months). RESULTS: With two exceptions, penetration of the anterior chamber with the 193 nm excimer laser was accomplished without deformation of the cut edges. The elliptical outline facilitated fitting of the graft into the recipient wound bed, and the orientation teeth made fitting even easier. Initial intraoperative complications due to excessive laser energy densities included minor thermally induced corneal alterations caused by the heat of the metal mask and in a few cases minimal iris bleeding during corneal penetration. The median duration of re-epithelialization was two days. Wound healing was without complications. In particular, no primary graft insufficiency and no unexpected effects in donor or recipient corneas, iris, lens or posterior segments were observed. Postoperative complications were one corneal ulcer caused by premature fitting of an extended-wear contact lens and two immunologic graft reactions (3%). Mean astigmatism after suture removal was 4.6 D with an elliptical outline, and 3.9 D after trephination with orientation teeth and with the sutures in situ. CONCLUSION: Non-mechanical, "non-thermal" trephination with elliptical and circular metal masks with orientation teeth represents a viable alternative to knife trephination in penetrating keratoplasty. No unexpected complications such as disturbances of wound healing were seen. Further studies are needed to determine the effect on residual long-term astigmatism after suture removal.

Adolescent↗

Optimized evaluation of a pulsed 2.09 microns holmium:YAG laser impact on the rat brain and 3 D-histomorphometry of the collateral damage.

Since more than 20 years CO2 and Nd:YAG lasers are established in the microsurgery of the nervous system. CO2 lasers can be used handheld, but may be focused on the target area by mirror optics and sideports of the operating microscope's micromanipulator. Nd:YAG lasers have the disadvantage of deep penetration into the brain and provocation of a large collateral damage. The need is for a fibre conducted solid system for surgery in delicate areas as for brain stem surgery. Fibre conduction of near infrared lasers allows better exposure of the target area compared to hollow wave guides or mirror equipment. Fibres can be tapered and modified according to the purpose. The holmium:YAG (Ho:YAG) laser has acquired interest by introducing the system into microsurgery of parenchymal tissue. They have not been proven yet sufficiently for neurosurgical tasks. The effort to minimalize the collateral tissue damage has to be maximalized in the surgery of nervous tissue and functional low redundant brain stem or spinal cord tissue. Volumetric data may be more precise in comparison to depth and width data of the laser lesion even when the different levels of the tissue interaction have to be analyzed for estimation of the real side effects in nervous tissue. We have used 50-800 ml delivered Ho:YAG single pulses in cortical areas of Sprague-Dawley rats and investigated the different lesion zones by volumetric data. The functional lesion zone was detected and measured by immunohistological staining of the heat shock protein HSP 72. For further reduction of the focus area, we have used tapered 400 to 200 microns fibres.

Animals↗

Origin of nodular lymphocyte-predominant Hodgkin's disease from a clonal expansion of highly mutated germinal-center B cells.

BACKGROUND: The atypical cells of nodular lymphocyte-predominant Hodgkin's disease, designated lymphocytic and histiocytic (L&H) cells, have a B-cell phenotype. To clarify the clonality of these cells, we studied rearranged immunoglobulin genes for the variable region of the heavy chain (V[H] genes) in individual L&H cells from 11 patients with nodular lymphocyte-predominant Hodgkin's disease. We also studied the expression of immunoglobulin light chains by those cells in six of the same patients. METHODS: Single CD20+ L&H cells were isolated from frozen sections by a technique of micromanipulation. The rearranged V(H) genes of these cells were amplified by the polymerase chain reaction (PCR), sequenced, and compared with germ-line V(H) genes. Immunoglobulin light-chain messenger RNA (mRNA) was detected by in situ hybridization. RESULTS: Of 615 L&H cells isolated from all the frozen sections, 160 yielded PCR products. In each of the 11 patients, the L&H cells that could be evaluated had identically rearranged V(H) genes, whether they were isolated from the same nodule, different nodules, or different blocks of tissue. All the V(H) sequences derived from the L&H cells were highly mutated (7.5 to 27.2 percent). In two cases the coding capacity of the V(H) genes was completely or partially disrupted by mutations. Intraclonal diversity was found in six cases, and monotypic immunoglobulin light-chain mRNA was found in six. CONCLUSIONS: The L&H cells of nodular lymphocyte-predominant Hodgkin's disease represent a monoclonal expansion of B cells. The high load of V(H) gene mutations and signs of intraclonal diversity suggest a relation between L&H cells and germinal-center B cells at the centroblastic stage of differentiation.

B-Lymphocytes↗

Clonality in nodular lymphocyte-predominant Hodgkin's disease.

BACKGROUND: There is general agreement that lymphocytic and histiocytic (L&H) cells, the variants of Reed-Sternberg cells in nodular lymphocyte-predominant Hodgkin's disease, belong to the B-cell lineage. However, the clonality of L&H cells remains controversial. METHODS: We used complementarity-determining region 3 (CDR3) of the immunoglobulin heavy-chain gene as a clonal marker to study individual L&H cells isolated by micromanipulation from tissue sections of five patients with nodular lymphocyte-predominant Hodgkin's disease. The heavy-chain CDR3 of each cell was amplified by the polymerase chain reaction. The products were analyzed by gel electrophoresis, and representative amplification products from each patient were sequenced. RESULTS: L&H cells whose heavy-chain CDR3 was related, indicating the presence of a clonal population, were detected in all five patients and were the dominant population in three. In four of the five patients, members of the clone were found in different nodules in the tissue section, different tissue blocks from the same tumor, or different lymph nodes from the same patient. The CDR3 sequences in each clone frequently contained nucleotide substitutions indicative of intraclonal mutation. CONCLUSIONS: Clonal populations of L&H cells occur in nodular lymphocyte-predominant Hodgkin's disease. Intraclonal variation in nucleotide sequences suggests that hypermutation of the heavy-chain CDR3 continues to occur among the clonal progeny.

B-Lymphocytes↗

Identification of common germinal-center B-cell precursors in two patients with both Hodgkin's disease and non-Hodgkin's lymphoma.

BACKGROUND: Hodgkin's disease and non-Hodgkin's B-cell lymphoma occasionally occur in the same patient. The identification of a common precursor of the two types of lymphoma would show definitively that Reed-Sternberg cells originate from B cells. METHODS: We studied lymphomas from two patients, one with a composite lymphoma (classic Hodgkin's disease and a follicular lymphoma in the same lymph node) and the other with a T-cell-rich B-cell lymphoma that was followed by classic Hodgkin's disease. Single Reed-Sternberg cells and non-Hodgkin's lymphoma cells from frozen sections were micromanipulated. The rearranged immunoglobulin variable-region genes (V genes) of the heavy and light chains were amplified by the polymerase chain reaction from genomic DNA and sequenced. RESULTS: In both patients, the Reed-Sternberg cells were related clonally to the non-Hodgkin's lymphoma B cells. The V genes carried somatic mutations (a hallmark of germinal-center B cells and their descendants). In both patients, some somatic mutations were shared by the Reed-Sternberg and non-Hodgkin's lymphoma cells, whereas other somatic mutations were found exclusively in one or the other cell type. CONCLUSIONS: In two patients with classic Hodgkin's disease and non-Hodgkin's B-cell lymphoma, we identified a common B-cell precursor, probably a germinal-center B-cell, for both lymphomas. This finding suggests that the two types of lymphoma underwent both shared and distinct transforming events and provides proof of the B-cell derivation of Reed-Sternberg cells in classic Hodgkin's disease.

Aged↗

A new laser treatment for vocal cord papilloma--585-nm pulsed dye.

OBJECTIVES: Microvascular targeting with the 585- nm pulsed dye laser (PDL) may provide a new form of therapy to control symptoms caused by recurrent respiratory papillomatosis (RRP). METHODS: Ten patients with RRP underwent 13 procedures under general anesthesia with the 585-nm PDL. A micromanipulator (11 procedures) and a flexible nasolaryngoscope (2 procedures) were used to deliver the laser pulses. Patients were followed postoperatively according to protocol. RESULTS: Clinical examination revealed regression of papillomas in all patients. Seven patients had complete regression after PDL surgery, and 2 patients had partial response to treatment. One patient was lost to follow-up. No complications were present during this prospective nonrandomized pilot study. CONCLUSION: Patients treated with PDL experienced regression of their papillomas. PDL may provide patients with RRP with an alternative treatment without the risks associated with CO(2) laser surgery. This procedure also has potential to be delivered on an outpatient basis with flexible fiberoptic laryngoscopes.

Adult↗