Biomedical subjects

M A Weiss

Publications and source records attributed to M A Weiss.

At least 37 records · Page 2Linked to original sources

PubMed2000

Treatment of poikiloderma of Civatte with an intense pulsed light source.

BACKGROUND: Effective treatment of poikiloderma of Civatte combines elimination of both the vascular and pigmented components simultaneously. A broad spectrum, noncoherent, intense pulsed light (IPL) source delivers multiple wavelengths with software controlled pulse durations and sequencing, which permits treatment of both vascular and pigmented lesions simultaneously. OBJECTIVE: To determine response and side effects of poikiloderma of Civatte of the neck and chest when treated by IPL. METHODS: One hundred and thirty-five patients randomly selected with typical changes of poikiloderma of Civatte on the neck and/or upper chest were treated with one to five treatments using IPL. RESULTS: Clearance of more than 75% of telangiectasias and hyperpigmentation comprising poikiloderma was observed. The incidence of side effects was 5%, including pigment changes. In many cases, improved skin texture was noted both by physician and patient. CONCLUSION: IPL is an effective mode of therapy for poikiloderma of Civatte. It offers a reduction of pigment and telangiectasias with a low risk profile. Additional benefits include subjective changes of improvement in skin texture.

Adult↗

PubMed2000

A phase I and II study of pentostatin (Nipent) with cyclophosphamide for previously treated patients with chronic lymphocytic leukemia.

Purine analogs and alkylating agents are the most active drugs in the treatment of patients with chronic lymphocytic leukemia (CLL). Although fludarabine is the most widely tested purine analog in CLL, myelosuppression has limited its use in combination chemotherapy regimens. Because pentostatin (Nipent; SuperGen, San Ramon, CA), a related purine analog with proven activity in CLL, has less myelosuppression, we postulated that it would prove advantageous and could be more readily combined with alkylating agents. We are conducting a phase I/II trial of combination chemotherapy with pentostatin and cyclophosphamide for previously treated patients with CLL. Patients need to have Rai high-risk disease or "active" intermediate-risk disease. The treatment regimen consists of a fixed dose of pentostatin (4 mg/m2) combined with an increasing dose of cyclophosphamide. We plan to treat cohorts of three patients each at cyclophosphamide dose levels of 600, 900, 1,200, 1,500, and 2,000 mg/m2. Cycles will be repeated every 21 days. If unacceptable toxicity is encountered at one dose level, then three additional patients (total of six patients) will be accrued to that dose level before further dose escalations will be permitted. A second instance of unacceptable toxicity will close that dose level and identify the preceding level as the phase II dose. Additional patients will be accrued to the phase II dose level to better assess response. Supportive measures include the use of granulocyte colony-stimulating factor (5 microg/kg/d) to limit neutropenia. Sulfamethoxazole/trimethoprim will be given as prophylaxis against Pneumocystis carinii pneumonia and acyclovir will be administered as prophylaxis for herpes zoster. Response will be assessed according to standard criteria, and flow cytometry and fluorescent in situ hybridization will be used to assess for minimal residual disease in patients with trisomy 12.

Acyclovir↗

PubMed1999

Hair removal with a non-coherent filtered flashlamp intense pulsed light source.

BACKGROUND AND OBJECTIVE: To evaluate the effects on disruption of hair growth of the non-coherent filtered flashlamp intense pulsed light (IPL) source. MATERIALS AND METHODS: Twenty-eight sites on 23 patients with Fitzpatrick type I-III were enrolled using a single treatment IPL followed for three months post-treatment. Another 56 on 48 patients with Fitzpatrick skin types I-V randomly enrolled for two treatments one month apart and followed for six months. STUDY DESIGN: Prior to beginning treatment and at each follow-up visit hair counts were obtained by averaging three 1-cm2 areas on a clear acetate template placed over the skin. Repeat hair counts and photographs were obtained at 2, 4, 8, and 12 weeks for the single treatment protocol and at additional 4, 5, and 6 months for the double treatment protocol. Parameters utilized were a 2.8-3.2 millisecond pulse duration typically for three pulses with thermal relaxation intervals of 20-30 milliseconds with a total fluence of 40-42 J/cm2. RESULTS: For the double treatment protocol hair clearance of 64% was achieved immediately following the second treatment. By week 8 reduction of hair counts was 42%. At 6 months, hair counts were reduced by 33%. CONCLUSIONS: Non-coherent IPL is an effective modality for long-term hair removal. IPL is safe with minimal side effects of epidermal injury or pigmentation change.

Female↗

PubMed1999

Periorbital skin resurfacing using high energy erbium:YAG laser: results in 50 patients.

OBJECTIVE: To evaluate Erbium:YAG regional periorbital laser resurfacing clinically and histologically. STUDY DESIGN/MATERIALS AND METHODS: Photographic evaluation before and after Erbium:YAG resurfacing with histologic evaluation of depth of injury. SETTING: Group private single specialty practice. PATIENTS: Fifty patients in the age range of 35-62 years, Fitzpatrick skin types I-III were treated using Erbium:YAG for regional resurfacing of periorbital rhytides. OUTCOME MEASURES: Patients were seen at days 1, 2, 3, 7, 14, 28, and at six months and one year. Photographs were obtained prior to application of topical anesthesia and were utilized to judge improvement of rhytides at all time intervals. Additional photographs were taken at each follow-up visit and the results judged by an independent investigator. Results were graded into five categories at all treatment intervals: no improvement, mild (grade 1: up to 25%), moderate (grade 2: 25-50%), good (grade 3: 50-75%, or excellent (grade 4: 75-100%). For histologic evaluation of depth of ablation and thermal injury one, two, and three passes at 21.2 J/cm2 were performed on four patients. RESULTS: Re-epithelization in the periorbital region was rapid with a mean duration of 2.65 days. Erythema ranged from a longest of six weeks to the shortest of seven days with a mean duration of 15.4 days. Evaluation of clinical results revealed that at two weeks mean improvement was 2.15 (between moderate and good). At four weeks further improvement was noted with a mean of 2.62. By six months, mean improvement score increased to 2.94. Minimal further improvement was noted between six months and one year with a mean improvement score of 3.02 (good to excellent). Histology revealed complete removal of the epidermis with one to three passes. Dermal ablation of 5-10 microns accompanied by small increases (5-10 microns) in dermal thermal injury occurred with each subsequent pass. CONCLUSIONS: We conclude that high energy Erbium:YAG periorbital resurfacing is a safe and effective modality which achieves substantial therapeutic effect. Most patients achieve approximately 75% improvement. Erythema fades quickly, reepithelization is rapid and side effects are minimal.

Adult↗

PubMed1999

Post-sclerotherapy compression: controlled comparative study of duration of compression and its effects on clinical outcome.

BACKGROUND: Although much has been published on the effects of compression on the venous system, relatively few studies address the duration of compression following sclerotherapy of telangiectatic webs associated with reticular veins. OBJECTIVE: To perform a controlled study comparing the effects of different durations of compression following sclerotherapy of reticular veins and telangiectasias in similar locations. METHOD: This study consisted of a total of 40 patients, 30 patients who received compression therapy and 10 control patients who did not receive compression therapy. The compression group consisted of 10 in each of three duration groups: 3 days, 1 week, and 3 weeks. Patients were evaluated at 1 week, 2 weeks, 6 weeks, 12 weeks, and 24 weeks for degree of improvement and side effects. RESULTS: The three compression groups showed significantly greater improvement at 6 weeks (p = .004). There was a strong correlation between the length of time compression was applied and degree of improvement at 6 weeks, 12 weeks, and 24 weeks of clinical follow-up; r = .74, p = .0006, r = .59, p = .006, r = .66, p = .0001, respectively. The patients treated with compression for 3 days and 1 week had more improvement than the control patients while the patients treated for 3 weeks of continuous compression had the most improvement. In terms of side effects, the 1 week and 3 week compression groups experienced the least amount of post-sclerotherapy hyperpigmentation. CONCLUSIONS: Compression enhances the results following sclerotherapy in a statistically significant way and is directly correlated with duration of compression. Three weeks of continuous compression leads to the best results, although even 3 days of compression results in greater improvement than no compression. Compression leads to a statistically significant reduction of post-sclerotherapy hyperpigmentation.

Adult↗

PubMed1999

Early clinical results with a multiple synchronized pulse 1064 NM laser for leg telangiectasias and reticular veins.

BACKGROUND: The 1064 nm wavelength penetrates tissue and blood vessels with little absorption by melanin. OBJECTIVE: To perform a study examining the effects of 1064 nm laser used in pulses from 4 msec to 16 msec on leg telangiectasias ranging in size from 0.5 to 3 mm. METHOD: In this initial trial, 50 sites on 30 patients were enrolled and treated with a multiple synchronized pulse laser at 1064 nm. The primary parameter utilized was a single 10-16 msec pulse. Improvement was judged by comparison of digital images at 1 month, 2 months, and 3 months posttreatment. Improvement was judged, based on size and number of vessels remaining. Side effects were noted as present or absent at each visit. RESULTS: Immediate contraction or darkening followed by urtication and visible total vessel closure as indicated by absence of blanching and visual elimination of the vessel border occurred in most of the treated sites. Two 3 mm diameter vessels were confirmed to be closed without flow by Duplex ultrasound visualization, using a 10 MHz transducer. Bruising from vessel rupture was seen in approximately 50% of the cases. No epidermal injury was noted in any sites, even in Fitzpatrick skin Types IV. At 3 months follow-up, 75% improvement was noted at treatment sites. CONCLUSIONS: Initial clinical results with a new multiple synchronized pulsed 1064 nm laser indicate that this longer wavelength supplied at pulses of up to 16 msec appears to be a valuable modality for immediate closure and subsequent elimination of leg ectatic veins. Epidermal injury is unlikely, as the near infrared wavelength has minimal interaction with melanin.

Follow-Up Studies↗

PubMed1998

Cell-associated pentosidine as a marker of aging in human diploid cells in vitro and in vivo.

Cellular aging is characterized by alterations at both the morphological and molecular levels, some of which are decreased mitotic rate, increased cytoplasmic vacuolization, and changes in intrinsic cellular constituents (Stanulis-Praeger, 1987. Mech. Ageing Dev. 38, 1-48). In the present investigation, glycoxidation is studied as a marker for cellular aging by measuring cell-associated pentosidine levels in human skin fibroblasts as a function of replicative life span and in human peripheral blood T lymphocytes as a function of chronological age. Fibroblasts were isolated from culture by detachment/centrifugation while lymphocytes were isolated from blood by a Ficoll-Paque/Lympho-Kwik T-Cell Prep technique. Pentosidine levels were measured in acid-hydrolyzed cell pellet suspensions by high-pressure liquid chromatography. Results show that pentosidine was detected in early and late cultured reticular and papillary fibroblasts. Pentosidine, expressed as either protein, DNA, or cell number, significantly (P < 0.0006) increased with in vitro passage and was significantly (P < 0.01) related to cell proliferation as measured by cell density and cell doublings per day during culture. Cell-associated pentosidine was measured in T lymphocytes isolated from healthy, diabetic, and uremic individuals. In healthy controls, levels significantly (P < 0.0003) increased with age. In uremic individuals, a large variation was observed with many values above the 95% confidence intervals determined for controls. Since a previous study showed that plasma pentosidine in healthy subjects does not increase with age, these results suggest that cellular turnover perhaps coupled to a deterioration in cellular anti-glycoxidation defensive mechanisms play a substantial role in explaining increased pentosidine concentrations during cellular aging.

Arginine↗

PubMed1998

High-resolution structure of an archaeal zinc ribbon defines a general architectural motif in eukaryotic RNA polymerases.

BACKGROUND: Transcriptional initiation and elongation provide control points in gene expression. Eukaryotic RNA polymerase II subunit 9 (RPB9) regulates start-site selection and elongational arrest. RPB9 contains Cys4 Zn(2+)-binding motifs which are conserved in archaea and homologous to those of the general transcription factors TFIIB and TFIIS. RESULTS: The structure of an RPB9 domain from the hyperthermophilic archaeon Thermococcus celer was determined at high resolution by NMR spectroscopy. The structure consists of an apical tetrahedral Zn(2+)-binding site, central beta sheet and disordered loop. Although the structure lacks a globular hydrophobic core, the two surfaces of the beta sheet each contain well ordered aromatic rings engaged in serial edge-to-face interactions. Basic sidechains are clustered near the Zn(2+)-binding site. The disordered loop contains sidechains conserved in TFIIS, including acidic residues essential for the stimulation of transcriptional elongation. CONCLUSIONS: The planar architecture of the RPB9 zinc ribbon-distinct from that of a conventional globular domain-can accommodate significant differences in the alignment of polar, non-polar and charged sidechains. Such divergence is associated with local and non-local changes in structure. The RPB9 structure is distinguished by a fourth beta strand (extending the central beta sheet) in a well ordered N-terminal segment and also differs from TFIIS (but not TFIIB) in the orientation of its apical Zn(2+)-binding site. Cys4 Zn(2+)-binding sites with distinct patterns of polar, non-polar and charged residues are conserved among unrelated RNAP subunits and predicted to form variant zinc ribbons.

Amino Acid Sequence↗

PubMed1998

Transcriptional activator-coactivator recognition: nascent folding of a kinase-inducible transactivation domain predicts its structure on coactivator binding.

A model of transcriptional activator-coactivator recognition is provided by the mammalian CREB activation domain and the KIX domain of coactivator CBP. The CREB kinase-inducible activation domain (pKID, 60 residues) is disordered in solution and undergoes an alpha-helical folding transition on binding to CBP [Radhakrishan, I., Perez-Alvarado, G. C., Parker, D., Dyson, H. J., Montminy, M. R., and Wright, P. E. (1997) Cell 91, 741-752]. Binding requires phosphorylation of a conserved serine (RPpSYR) in pKID associated in vivo with the biological activation of CREB signaling pathways. The CBP-bound structure of CREB contains two alpha-helices (designated alphaA and alphaB) flanking the phosphoserine; the bound structure is stabilized by specific interactions with CBP. Here, the nascent structure of an unbound pKID domain is characterized by multidimensional NMR spectroscopy. The solubility of the phosphopeptide (46 residues) was enhanced by truncation of N- and C-terminal residues not involved in pKID-CBP interactions. Although disordered under physiologic conditions, the pKID fragment and its unphosphorylated parent peptide exhibit partial folding at low temperatures. One recognition helix (alphaA) is well-defined at 4 degreesC, whereas the other (alphaB) is disordered but inducible in 40% trifluoroethanol (TFE). Such nascent structure is independent of serine phosphorylation and correlates with the relative extent of engagement of the two alpha-helices in the pKID-KIX complex; whereas alphaA occupies a peripheral binding site with few intermolecular contacts, the TFE-inducible alphaB motif is deeply engaged in a hydrophobic groove. Our results support the use of TFE as an empirical probe of hidden structural propensities and define a correspondence between induced fit and the nascent structure of peptide fragments.

Amino Acid Sequence↗

PubMed1998

Mini-proinsulin and mini-IGF-I: homologous protein sequences encoding non-homologous structures.

Protein minimization highlights essential determinants of structure and function. Minimal models of proinsulin and insulin-like growth factor I contain homologous A and B domains as single-chain analogues. Such models (designated mini-proinsulin and mini-IGF-I) have attracted wide interest due to their native foldability but complete absence of biological activity. The crystal structure of mini-proinsulin, determined as a T3R3 hexamer, is similar to that of the native insulin hexamer. Here, we describe the solution structure of a monomeric mini-proinsulin under physiologic conditions and compare this structure to that of the corresponding two-chain analogue. The two proteins each contain substitutions in the B-chain (HisB10-->Asp and ProB28-->Asp) designed to destabilize self-association by electrostatic repulsion; the proteins differ by the presence or absence of a peptide bond between LysB29 and GlyA1. The structures are essentially identical, resembling in each case the T-state crystallographic protomer. Differences are observed near the site of cross-linking: the adjoining A1-A8 alpha-helix (variable among crystal structures) is less well-ordered in mini-proinsulin than in the two-chain variant. The single-chain analogue is not completely inactive: its affinity for the insulin receptor is 1500-fold lower than that of the two-chain analogue. Moreover, at saturating concentrations mini-proinsulin retains the ability to stimulate lipogenesis in adipocytes (native biological potency). These results suggest that a change in the conformation of insulin, as tethered by the B29-A1 peptide bond, optimizes affinity but is not integral to the mechanism of transmembrane signaling. Surprisingly, the tertiary structure of mini-proinsulin differs from that of mini-IGF-I (main-chain rms deviation 4.5 A) despite strict conservation of non-polar residues in their respective hydrophobic cores (side-chain rms deviation 4.9 A). Three-dimensional profile scores suggest that the two structures each provide acceptable templates for threading of insulin-like sequences. Mini-proinsulin and mini-IGF-I thus provide examples of homologous protein sequences encoding non-homologous structures.

Amino Acid Sequence↗

PubMed1998

RNA recognition by arginine-rich peptide motifs.

A ubiquitious class of RNA-binding proteins is distinguished by an arginine-rich motif. Such proteins function in transcription, translation, RNA trafficking, and packaging. Peptide models are derived from viral regulatory proteins, including the virulence factors Tat and Rev of mammalian immunodeficiency viruses. Structures of model peptide-RNA complexes exhibit diverse strategies of recognition based in each case on structural transitions. Induced RNA structures contain noncanonical elements such as purine-purine mismatches, base triples, and flipped bases. Such elements enlarge and extend the RNA major groove to create specific peptide-binding pockets and surfaces. The repertoire of bound peptide structures--beta-hairpin, alpha-helix, and helix-bend-helix-reflects the diversity of induced RNA architectures. This repertoire, reminiscent of primordial exon-encoded peptides, may recapitulate early events in the transition between RNA and protein worlds. Peptide-directed changes in modern RNA structures can provide a mechanism of signaling in higher-order RNA-protein assemblies.

Arginine↗

PubMed1998

RNA-mediated signaling in transcription.

Structures of phage transcriptional antitermination complexes define novel motifs for recognition of RNA hairpins by arginine-rich peptides. A bent alpha-helix in each case follows the contour of an induced GNRA-like fold. A phage-specific pattern of base pairing, base stacking and base flipping underlies biological specificity and permits engagement with RNA polymerase. The structures suggest a mechanism of RNA-mediated signaling in transcriptional regulation.

Amino Acid Sequence↗

PubMed1998

A phase I trial of a single high dose of idarubicin combined with high-dose cytarabine as induction therapy in relapsed or refractory adult patients with acute lymphoblastic leukemia.

Relapsed or refractory adult acute lymphoblastic leukemia (ALL) carries a grave prognosis. The most promising strategy for curing these patients is through re-induction chemotherapy followed by successful allogeneic transplant. We studied a new high-dose induction regimen in order to improve the outcome for these patients. Eighteen adult patients with relapsed/refractory ALL were treated on a phase I study of high-dose cytarabine combined with a single escalating dose of idarubicin. Five patients had primary refractory disease and 13 were treated in refractory relapse. Nine patients (50%) had Ph+ ALL. The induction regimen was cytarabine 3 g/m2/day intravenously days 1-5 and idarubicin as a single intravenous dose on day 3. G-CSF 5 microg/kg subcutaneously every 12 h was started on day 7. The initial idarubicin dose was 20 mg/m2 with dose escalations of 10 mg m2. Cohorts of three patients were treated at each idarubicin dose level. Unacceptable toxicity was encountered at 50 mg/m2 with one death from infection and one death from cardiotoxicity in a patient with significant prior anthracycline exposure. There were no instances of grade 4 non-hematologic toxicity encountered at idarubicin doses of 20 mg/m2, 30 mg/m2, or 40 mg/m2. The data suggest a dose-response relationship for increasing doses of idarubicin with 0/3 complete responses (CR) at 20 mg/m2, 1/3 CR at 30 mg/m2, and 7/12 (58%) CR at idarubicin doses > or = 40 mg/m2. We conclude that concomitant administration of cytarabine 3 g/m2/day x 5 and high-dose idarubicin at 40 mg/m2 as a single dose on day 3 can be administered safely to patients with refractory and relapsed ALL.

Adult↗

PubMed1997

RNA recognition by a bent alpha-helix regulates transcriptional antitermination in phage lambda.

A novel RNA recognition motif is characterized in an arginine-rich peptide. The motif, derived from lambda transcriptional antitermination protein N, regulates an RNA-directed genetic switch. Its characterization by multidimensional nuclear magnetic resonance (NMR) demonstrates specific RNA-dependent folding of N- and C-terminal recognition helices separated by a central bend. The biological importance of the bent alpha-helix is demonstrated by mutagenesis: binding is blocked by substitutions in the N peptide or its target (the boxB RNA hairpin) associated in vivo with loss of transcriptional antitermination activity. Although arginine side chains are essential, the peptide is also anchored to boxB by specific nonpolar contacts. An alanine in the N-terminal helix docks in the major groove of the RNA stem whereas a tryptophan in the C-terminal helix stacks against a purine in the RNA loop. At these positions all 19 possible amino acid substitutions have been constructed by peptide synthesis; each impairs binding to boxB. The pattern of allowed and disallowed substitutions is in accord with the results of random-cassette mutagenesis in vivo. The helix-bend-helix motif rationalizes genetic analysis of N-dependent transcriptional antitermination and extends the structural repertoire of arginine-rich domains observed among mammalian immunodeficiency viruses.

Amino Acid Sequence↗

PubMed1997

An RNA enhancer in a phage transcriptional antitermination complex functions as a structural switch.

Antitermination protein N regulates the transcriptional program of phage lambda through recognition of RNA enhancer elements. Binding of an arginine-rich peptide to one face of an RNA hairpin organizes the other, which in turn binds to the host antitermination complex. The induced RNA structure mimics a GNRA hairpin, an organizational element of rRNA and ribozymes. The two faces of the RNA, bridged by a sheared GA base pair, exhibit a specific pattern of base stacking and base flipping. This pattern is extended by stacking of an aromatic amino acid side chain with an unpaired adenine at the N-binding surface. Such extended stacking is coupled to induction of a specific internal RNA architecture and is blocked by RNA mutations associated in vivo with loss of transcriptional antitermination activity. Mimicry of a motif of RNA assembly by an RNA-protein complex permits its engagement within the antitermination machinery.

Amino Acid Sequence↗

PubMed1997

Putative folding pathway of insulin-like growth factor-I.

Insulin-like growth factor-I (IGF-I) has three disulfide bonds and refolding of the fully reduced molecule generates varying ratios of correctly (PII) and incorrectly (PI) folded forms via several intermediates. All of the intermediates have the disulfide bond between Cys18 and 61 formed, indicating that formation of this disulfide is the first step in refolding. In order to further understand the refolding pathway, two intermediate froms, PIII with the additional disulfide Cys(6/47) formed and PIIIa with Cys(6/48) formed, were isolated. The oxidation of the remaining Cys48 and 52 in PIII and Cys47 and 52 in PIIIa would lead to PI and PII, respectively; however, air oxidation of these resulted in a rapid reshuffling into other intermediates as well as folding into the fully oxidized forms, and this occurred whether refolding was started with PIII or PIIIa. When oxidation occurred in the presence of an excess of oxidized glutathione, the predominant species generated were various glutathione adducts regardless of the initial intermediate form, indicating that formation of the last disulfide bond is not a favorable process relative to disulfide exchange when excess disulfides from oxidized glutathione are present. Interestingly, if 80 microM copper sulfate, an oxidant, is added to the refolding buffer, PIII resulted in formation of the PI form alone, whereas PIIIa resulted in the PII form alone. It was concluded from these results that the intermediate forms of IGF-1 can rapidly reshuffle between different disulfide structures, and that formation of the last disulfide bond is not as favorable a process as the conversion to other intermediates. The oxidation to form the last disulfide bond in PIII or PIIIa is accelerated and hence the interconversion to other intermediates is kinetically minimized only in the presence of copper sulfate. It appears, therefore, that the two intermediate forms, PIII and PIIIa, are the precursors of the corresponding fully oxidized forms, but their conversions are not energetically a favorable process.

Chromatography, High Pressure Liquid↗

PubMed1997

Electrostatics and hydration at the homeodomain-DNA interface: chemical probes of an interfacial water cavity.

Electrostatics and hydration of a homeodomain-DNA complex are dissected by chemical modification. Selective neutralization of phosphate charges by methylphosphonate substitution demonstrates the differential importance of short- and long-range electrostatic interactions. Whereas the footprint of direct contacts is in accord with crystal structures, interference is also observed at non-contacted sites. Such sites adjoin a novel interfacial water cavity in the major groove. Non-contacted phosphodiester groups in the cavity are proposed to contribute to long-range ordering of an extended protein-water-DNA interface. Use of isolated S(p) and R(p) methylphosphonate diastereomers demonstrates that interference at this extended interface is stereoselective and charge-independent. Attenuation of protein binding presumably reflects groove-specific reorganization of bound water. Surprisingly, such attenuation can exceed that due to neutralization of a direct phosphate-side-chain salt bridge. These results support the hypothesis that hydration of an interfacial cavity functions as a non-covalent extension of the DNA surface. Stereo-specific interrogation of bound water by chemical synthesis provides a general method to assess the coupling between solvation and DNA recognition.

Bacterial Proteins↗

PubMed1997

Viral-mediated gene transfer in the cochlea.

Gene transfer is an exciting new tool in medical therapy and scientific investigation, but only very recently has it begun to be developed in the auditory system. This paper describes in vivo and ex vivo experiments using an adenoviral vector (Ad. RSVntlacZ), which is a replication-deficient virus based on a human adenoviral (serotype 5) genomic backbone. The in vivo experiments demonstrate successful gene transfer into multiple types of cochlear cells. We observed a relatively efficient transduction, several weeks of sustained transgene expression and an absence of major lethal cytotoxicity in spiral ganglion and epithelial cells of the cochlea in adult animals. The ex vivo experiments were performed using fibroblasts transduced in vitro with Ad. RSVntlacZ. Two weeks after inoculation of the fibroblasts into the perilymph, we observed transplanted fibroblasts, which were adherent to the lining of the perilymphatic spaces, and were expressing the lacZ transgene. We speculate that, as the genetic basis of degenerative cochlear diseases is characterized on a mutational level, transgene expression will allow us to test hypotheses regarding the effects of specific genes on cochlear cell biology. Gene transfer will not only increase our understanding of the pathophysiology of hearing loss, but also may provide gene therapy for disease.

Adenoviridae↗