PubMed Health⌕ Search

Biomedical subjects

T Herman

Publications and source records attributed to T Herman.

At least 37 records · Page 2Linked to original sources
PubMed1995

Prosthetic fitting and ambulation in a paraplegic patient with an above-knee amputation.

The combination of paraplegia with an above-knee amputation is a complex injury that makes the rehabilitation process difficult. This article describes a case of T12 paraplegia and an above-knee amputation. After the rehabilitation course, the patient achieved full ambulatory independence with an ischial containment, contoured adducted trochanteric controlled alignment method (CATCAM) prosthesis and a knee ankle foot orthosis (KAFO). Difficulties in fitting a functional prosthesis to an insensate limb and the rehabilitation stages leading to functional ambulation are reviewed.

Activities of Daily Living↗
PubMed1994

Characterization of a Max:DNA complex by cross-linking to photoactive oligonucleotides.

The structure of the Max:DNA complex was investigated by cross-linking Max to a series of photoactive oligonucleotides. A single photoactive aryl azide was introduced into oligonucleotides at defined positions downstream from the specific CACGTG binding site. Purified Max homodimers bound to and were cross-linked to oligonucleotides containing a photoactive group either 2, 5, 8, or 11 bp downstream from the binding site. Further analysis revealed that an amino-terminal chymotryptic peptide of Max was cross-linked to the oligonucleotide containing a photoactive probe 11 bp downstream from the specific binding site. This result is consistent with the recent crystal structure of the Max:DNA complex (Ferré-D'Amaré et al., 1993) and further suggests that amino acid residues near the amino-terminus of Max are in close proximity to a region of DNA that is separated from the core binding site by one turn of the double helix.

Amino Acid Sequence↗
PubMed1991

Cloning and expression of APE, the cDNA encoding the major human apurinic endonuclease: definition of a family of DNA repair enzymes.

Abasic (AP) sites are common, potentially mutagenic DNA damages that are attacked by AP endonucleases. The biological roles of these enzymes in metazoans have not been tested. We have cloned the human cDNA (APE) that encodes the main nuclear AP endonuclease. The predicted Ape protein, which contains likely nuclear transport signals, is a member of a family of DNA repair enzymes that includes two bacterial AP endonucleases (ExoA protein of Streptococcus pneumoniae and exonuclease III of Escherichia coli) and Rrp1 protein of Drosophila melanogaster. Purified Ape protein lacks the 3'-exonuclease activity against undamaged DNA that is found in the bacterial and Drosophila enzymes, but the lack of obvious amino acid changes to account for this difference suggests that the various enzyme functions evolved by fine tuning a conserved active site. Expression of the active human enzyme in AP endonuclease-deficient E. coli conferred significant resistance to killing by the DNA-alkylating agent methyl methanesulfonate. The APE cDNA provides a molecular tool for analyzing the role of this central enzyme in maintaining genetic stability in humans.

Amino Acid Sequence↗
PubMed1991

Two distinct human DNA diesterases that hydrolyze 3'-blocking deoxyribose fragments from oxidized DNA.

Mammalian cells were investigated for enzymes that help correct oxidative damages in DNA. We focused on 3'-repair diesterases, which process DNA ends at oxidative strand breaks by removing 3'-blocking fragments of deoxyribose that prevent DNA repair synthesis. Two enzymes were found in a variety of mouse, bovine and human tissues and cultured cells. The two activities were purified to differing degrees from HeLa cells. One enzyme had the properties of the known HeLa AP endonuclease (Mr approximately 38,000, with identical substrate specificity and reaction requirements, and cross-reactivity with anti-HeLa AP endonuclease antiserum) and is presumed identical to that protein. The second activity did not interact with anti-HeLa AP endonuclease antibodies and had relatively less AP endonuclease activity. This second enzyme may have been detected in other studies but never characterized. In addition to the 3'-repair diesterase and AP endonuclease, this partially purified preparation also harbored DNA 3'-phosphatase and 3'-deoxyribose diesterase activities. It is unknown whether all activities detected in the second preparation are due to a single protein, although activity against undamaged DNA was not detected. The in vivo roles of these two widely distributed 3'-repair diesterase/AP endonucleases have not been determined, but with the characterizations presented here such questions may now be focused.

Animals↗
PubMed1991

Affinity isolation of active murine erythroleukemia cell chromatin: uniform distribution of ubiquitinated histone H2A between active and inactive fractions.

This laboratory recently reported the development of a biotin-cellulose/streptavidin affinity chromatography method based on the DNase I sensitivity of active chromatin to isolate a DNA fraction from murine erythroleukemia (MEL) cells that is more than 15-fold enriched in active genes (Dawson et al.: Journal of Biological Chemistry 264:12830-12837, 1989). We now report the extension of this technique to isolate and characterize chromatin that is enriched in active genes. In this approach, DNA in nuclei isolated from MEL cells was nicked with DNase I at a concentration that does not digest the active beta-globin gene, followed by repair of the nicks with a cleavable biotinylated nucleotide analog, 5-[(N-biotin-amido)hexanoamido-ethyl-1,3'-dithiopropionyl-3- aminoallyl]-2'- deoxyuridine 5'-triphosphate (Bio-19-SS-dUTP), during a nick-translation reaction. After shearing and sonication of the nuclei to solubilize chromatin, chromatin fragments containing biotin were separated from non-biotinylated fragments by sequential binding to streptavidin and biotin cellulose. The bound complex contained approximately 10% of the bulk DNA. Reduction of the disulfide bond in the biotinylated nucleotide eluted approximately one-half of the affinity isolated chromatin. Hybridization analysis of DNA revealed that whereas inactive albumin sequences were equally distributed among the chromatin fractions, virtually all of the active beta-globin sequences were associated with chromatin fragments which had bound to the affinity complex. Western blot assessment for ubiquitinate histones revealed that ubiquitinated histone H2A (uH2A) was uniformly distributed among active (bound) and inactive (unbound) chromatin fractions.

Blotting, Western↗
PubMed1991

RTOG quality assurance guidelines for clinical trials using hyperthermia administered by ultrasound.

Clinical quality assurance guidelines are established for RTOG hyperthermia protocols in which unfocused planar ultrasound may be used to administer hyperthermia. Measurement of temperature at a few fixed points is no longer considered to be adequate. Thermal mapping is required to obtain profiles of the temperature across the tumor dimensions, including margins of normal tissue. The thermometry strategies established for microwaves are to be adhered to with oblique insertion of the probes recommended. Two types of errors arise which are generally not present with microwaves. A measurement error, commonly referred to as a temperature artifact, arises because of absorption and/or viscous heating of the probe. Another error arises when thermocouples are used due to the conduction of heat along the wire leads, especially the copper wire. Several thermometry systems are evaluated with regard to the expected artifact and conduction errors. Acceptable systems include: a) indexing a polyurethane sheathed single sensor thermocouple in a polyurethane catheter, b) indexing a fiberoptic probe in a steel needle, c) indexing a single sensor thermocouple in a steel needle, and d) use of manganin-constantan multisensor thermocouples. Unacceptable systems include: a) fixed or static probes that do not provide profiles of the temperature across the tumor dimensions, b) copper-constantan multisensor thermocouples, and c) teflon sheathed thermocouples inserted into a teflon catheter.

Clinical Protocols↗
PubMed1991

RTOG quality assurance guidelines for clinical trials using hyperthermia for deep-seated malignancy.

Quality assurance has been vague or lacking in many previous hyperthermia trials. Recent publications by the Hyperthermia Physics Center, the Center for Devices and Regulatory Health, and the Radiation Therapy Oncology Group have described general guidelines for quality assurance in equipment reliability and reproducibility, superficial applications, and microwave techniques. The present report details quality assurance factors that are believed to be important for hyperthermia of deep clinical sites, defined as extending at least 3 cm beyond the skin surface. This document will discuss patient and physician factors, as well as thermometric accuracy, assessment of specific absorption rates (SAR), assurance of adequate coverage of tumors by the energy deposition pattern of the treatment device, and recommended documentation of the location, quantity, and frequency of treatment, specifically oriented to deep hyperthermia. The recommendations are structured to facilitate compliance in multiinstitutional trials.

Clinical Protocols↗
PubMed1991

RTOG quality assurance guidelines for interstitial hyperthermia.

This document specifies the current recommendations for quality assurance for hyperthermia administration with interstitial techniques as specified by the Radiation Therapy Oncology Group (RTOG). The document begins by providing a brief description of the physical principles behind the use of the three most commonly used methods of interstitial hyperthermia: radiofrequency (RF-LCF), microwave antennas, and ferromagnetic seeds. Emphasis is placed on features that effect quality assurance. Specific recommendations are provided for: a) Pretreatment planning and equipment performance checks, b) Implant considerations and documentation, c) Thermometry, and d) Safety procedures. Specific details regarding quality assurance issues that are common to all local and regional hyperthermia methods are outlined in previous documents sponsored by the RTOG. It is anticipated that technological advances may lead to future modifications of this document.

Documentation↗
PubMed1990

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease).

Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a unique disease of unknown etiology with a childhood predilection. Reports have established the worldwide distribution of the disorder. Although peripheral lymphadenopathy is the most common mode of presentation, numerous studies and individual case reports have established the fact that 30-40% of affected individuals have extranodal manifestations particularly in the head and neck region where the adenopathy tends to be concentrated. As yet, the pathogenesis of SHML has not been established but speculation relates the disorder to an aberrant response to an unspecified antigen, possibly an infectious organism. Because of the clinical manifestations, the radiographic features of SHML are not pathognomonic but rather engender a differential diagnosis which includes lymphomatous, pseudolymphomatous and infectious conditions. Appropriate imaging of patients with SHML depends upon presenting symptoms and signs. Radionuclide bone scanning may be helpful in the evaluation of suspected skeletal lesions or joint symptoms. Gallium scanning is often positive in nodal disease and CT, MRI and sonography are helpful in the evaluation of extranodal sites of involvement such as the orbit, eyelid, upper aero-digestive tract and retroperitoneum.

Adolescent↗
PubMed1989

Affinity isolation of transcriptionally active murine erythroleukemia cell DNA using a cleavable biotinylated nucleotide analog.

We have developed an affinity technique to obtain active gene domains from murine erythroleukemia cell nuclei, based on the differential sensitivity of potentially active and inactive chromatin to DNase I. Nuclei isolated from potentially active noninduced cells and transcriptionally active induced MEL cells were treated with DNase I at concentrations which did not digest the beta-globin gene, followed by repair using a typical nick translation reaction during which a cleavable biotinylated nucleotide analog, 5-[N-biotinamido)hexanoamido-ethyl-1,3-dithiopropionyl -3-aminoallyl]-2'- deoxyuridine 5'-triphosphate (Bio-19-SS-dUTP), was inserted into DNA sequences. Following purification and digestion with EcoRI restriction endonuclease, biotinylated sequences were affinity isolated by sequential binding to streptavidin and biotincellulose. The streptavidin/biotin-cellulose complex bound up to 80% of the nick-translated DNA, which comprised a small percentage of the total nuclear DNA. Cleavage of the disulfide bond in the linker arm of the biotinylated nucleotide resulted in elution of virtually all of the affinity isolated sequences. Hybridization analysis of this fraction of DNA revealed up to a 16-fold enrichment for the active beta-globin gene, as compared with DNA which did not bind to the biotincellulose. Conversely, the inactive alpha-fetoprotein gene was barely detectable in affinity isolated DNA from noninduced cells and was 2-fold depleted in samples from induced cells.

Acetamides↗
PubMed1988

Malignant mesothelioma: prognostic variables in a registry of 180 patients, the Dana-Farber Cancer Institute and Brigham and Women's Hospital experience over two decades, 1965-1985.

All mesothelioma patients identified by a computer search of pathologic diagnoses at the Dana-Farber Cancer Institute (DFCI) between 1965 and 1985 were the subjects of this analysis. A total of 180 patients were identified, 136 with pleural and 37 with peritoneal mesothelioma. There were five pericardial and two testicular primaries. Of the two decades included in the study, later patients were significantly older, with a more advanced disease stage, and a lower performance status than those accrued early in the study. Factors at diagnosis associated with a significantly prolonged survival for all patients with mesothelioma included a 0 to 1 performance status, absence of chest pain, age less than 50 years, and epithelial histology. Factors at diagnosis associated with prolonged survival for the subset of patients with pleural mesothelioma included epithelial histology, 0 to 1 performance status, the absence of chest pain, an interval of greater than 6 months from onset of symptoms, and treatment with chemotherapy and pleuropneumonectomy. This last result must be interpreted with caution, since this was not a randomized study.

Boston↗
PubMed1988

Combined modality treatment of peritoneal mesotheliomas.

Five patients with peritoneal mesothelioma were treated with a multimodality approach consisting of debulking surgery, ip chemotherapy, and whole-abdomen irradiation. Chemotherapy included cisplatin and doxorubicin; radiation was given by an open-field technique. Three patients remain disease free at 46, 60, and 61 months after diagnosis. This treatment approach may serve as a model for common tumors characterized by abdominal carcinomatosis.

Adult↗
PubMed1987

Long-term survival in peritoneal mesothelioma. The role of radiotherapy and combined modality treatment.

Ten patients with peritoneal mesothelioma were treated at the Joint Center for Radiation Therapy between 1968 and 1985. Six of the ten patients remained free of disease at 19+ to 78+ months after diagnosis. The six patients received sequential surgical debulking, combination chemotherapy, and whole-abdomen irradiation. Four patients not treated with this multimodality approach died with disease. This approach may have an impact on the natural course of peritoneal mesothelioma, and warrants further study.

Adult↗
PubMed1986

Affinity isolation of transcriptionally active DNA.

Chicken erythrocyte nuclei were nick translated with the chemically cleavable biotinylated nucleotide, Bio-12-SS-dUTP. DNA was purified, digested with restriction endonucleases, and applied to an avidin-agarose affinity column. Seventy percent of the nick translated DNA bound to the column. This DNA was recovered from the column by chemical cleavage of the linker arm joining biotin to the DNA. Dot hybridization analysis of this DNA revealed a significant enrichment of the alpha-D-globin gene. This result suggests an approach to isolate transcriptionally active genes.

Animals↗
PubMed1986

Pneumatosis intestinalis in cystic fibrosis.

We retrospectively reviewed the clinical and radiographic findings in patients with pneumatosis intestinalis (PI), who were identified among 441 patients with cystic fibrosis. Since 1944, the age at onset and the incidence of PI have increased. Pneumomediastinum, pneumothorax, or pulmonary interstitial emphysema was found in 95% of patients with PI compared with 62% of patients without PI. The type, distribution, and severity of PI often changed with time. PI is correlated with the development of obstructive pulmonary disease, which facilitates air dissection into interstitial spaces. Dissection of air is often clinically silent and tends to be self-perpetuating.

Adolescent↗
PubMed1985

A chemically cleavable biotinylated nucleotide: usefulness in the recovery of protein-DNA complexes from avidin affinity columns.

A biotinylated nucleotide analog containing a disulfide bond in the 12-atom linker joining biotin to the C-5 of the pyrimidine ring has been synthesized. This analog, Bio-SS-dUTP, is an efficient substrate for Escherichia coli DNA polymerase I. Bio-SS-dUTP supported DNA synthesis in a standard nick-translation reaction at 35%-40% the rate of an equal concentration of the normal nucleotide, TTP. DNA containing this analog was bound to an avidin-agarose affinity column and subsequently eluted after reduction of the disulfide bond by dithiothreitol. The ability to recover biotinylated DNA from an avidin affinity column under nondenaturing conditions should prove useful in the isolation of specific protein-DNA complexes. As a demonstration of this approach, Bio-SS-DNA was reconstituted with histones to form 11S monomer nucleosomes. Bio-SS-nucleosomes were shown to selectively bind to avidin-agarose. Ninety percent of the bound Bio-SS-nucleosomes were recovered from the affinity column by elution with buffer containing 50-500 mM dithiothreitol. The recovered nucleosomes were shown to be intact 11S particles as judged by velocity sedimentation in a sucrose gradient. This approach may prove to be generally useful in the isolation of protein-DNA complexes in a form suitable for further analysis of their native unperturbed structure.

Affinity Labels↗
PubMed1985

Studies of bronchial secretion. The influence of inflammatory response and bacterial infection.

Bronchial secretions obtained during bronchoscopic examination of 60 children suffering from respiratory tract infections were studied for the concentration of immunoglobulins, anti-proteolytic factors, lactoferrin, and lysozyme. Eleven children having bronchial asthma without a history of chronic or recurrent infections of the respiratory tract were designated as a control. The results were analysed in relation to clinical diagnosis (chronic bronchitis, bronchitis, bronchiectasis) or to the local status of bronchial mucosa at the time of bronchoscopy (no inflammation, inflammation, inflammation with documented bacterial infection). The statistical analysis of the results revealed a decrease of lactoferrin and locally produced IgA in the group of children suffering from bronchitis and chronic bronchitis. Samples infected with Haemophilus species had significantly higher concentration of lactoferrin than any other group. Similarly, albumin in this group was higher than in the other group except that other bacteria were present. Samples infected with Haemophilus also had increased concentrations of S-IgA, IgG, and anti-proteolytic factors when compared with the group without local inflammation.

Bacterial Infections↗