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Biomedical subjects

J Stringer

Publications and source records attributed to J Stringer.

At least 19 recordsLinked to original sources

Urinary incontinence in familial dysautonomia.

The aim of this study was to determine the prevalence of urinary incontinence in women with familial dysautonomia (FD). A telephone survey was conducted on 68 known surviving female FD patients over 13 years of age registered with the Dysautonomia Centers in the USA and Israel. The mean age of the surveyed group was 27.1+/-9.8 years and 99% of the patients were nulliparous. The overall reported prevalence of urinary incontinence was 82% (n=56). Of the patients with incontinence, 59% (n=33) reported stress incontinence, 11% (n=6) reported urge incontinence, and 30% (n=17) reported symptoms of both, or mixed incontinence. In most women urinary loss was both small and infrequent, but 36% of women (n=20) with incontinence experienced a loss sufficient to necessitate the use of protection (panty liners, pads or diapers); in 7% (n=4) such loss occurred daily. Twelve per cent of all women with FD surveyed experienced primary nocturnal enuresis and 26% experienced nocturia. The prevalence of urinary incontinence is high in young female patients with familial dysautonomia. Neurophysiologic testing in this population may provide a better understanding of the role of the autonomic nervous system in urinary incontinence.

Adult↗

Structural studies of biomaterials using double-quantum solid-state NMR spectroscopy.

Proteins directly control the nucleation and growth of biominerals, but the details of molecular recognition at the protein-biomineral interface remain poorly understood. The elucidation of recognition mechanisms at this interface may provide design principles for advanced materials development in medical and ceramic composites technologies. Here, we describe both the theory and practice of double-quantum solid-state NMR (ssNMR) structure-determination techniques, as they are used to determine the secondary structures of surface-adsorbed peptides and proteins. In particular, we have used ssNMR dipolar techniques to provide the first high-resolution structural and dynamic characterization of a hydrated biomineralization protein, salivary statherin, adsorbed to its biologically relevant hydroxyapatite (HAP) surface. Here, we also review NMR data on peptides designed to adsorb from aqueous solutions onto highly porous hydrophobic surfaces with specific helical secondary structures. The adsorption or covalent attachment of biological macromolecules onto polymer materials to improve their biocompatibility has been pursued using a variety of approaches, but key to understanding their efficacy is the verification of the structure and dynamics of the immobilized biomolecules using double-quantum ssNMR spectroscopy.

Amino Acid Sequence↗

Two Japanese variants of the absolute transvestite film.

This essay compares two Japanese transvestite films from different generations-Black Lizard of 1968 and Summer Vacation 1999 of 1988. While Western transvestite conventions are usually exploited only to climactically reinforce heterosexual coupling, what binds these two films is their divergent tradition of what I call "permanent transvestism." That is, the films employ a cross-dressing which occurs extra-diegetically, is unnecessary to the plot, and which an audience may or may not be aware of depending on their geo-historical position. However, it is this non-Western tradition of cross-dressing that nevertheless imparts an aestheticization of sexual desire beyond fixed categories of "gay," "lesbian," or even our conventional ideas of transsexualism.

Art↗

Chromosomal breakpoint positions suggest a direct role for radiation in inducing illegitimate recombination between the ELE1 and RET genes in radiation-induced thyroid carcinomas.

The RET/PTC3 rearrangement is formed by fusion of the ELE1 and RET genes, and is highly prevalent in radiation-induced post-Chernobyl papillary thyroid carcinomas. We characterized the breakpoints in the ELE1 and RET genes in 12 post-Chernobyl pediatric papillary carcinomas with known RET/PTC3 rearrangement. We found that the breakpoints within each intron were distributed in a relatively random fashion, except for clustering in the Alu regions of ELE1. None of the breakpoints occurred at the same base or within a similar sequence. There was also no evidence of preferential cleavage in AT-rich regions or other target DNA sites implicated in illegitimate recombination in mammalian cells. Modification of sequences at the cleavage sites was minimal, typically involving a 1-3 nucleotide deletion and/or duplication. Surprisingly, the alignment of ELE1 and RET introns in opposite orientation revealed that in each tumor the position of the break in one gene corresponded to the position of the break in the other gene. This tendency suggests that the two genes may lie next to each other but point in opposite directions in the nucleus. Such a structure would facilitate formation of RET/PTC3 rearrangements because a single radiation track could produce concerted breaks in both genes, leading to inversion due to reciprocal exchange via end-joining.

Adolescent↗

Gastric cancer and metastasis to the brain.

BACKGROUND: Metastasis of gastric carcinoma to the brain is very uncommon. At The University of Texas M. D. Anderson Cancer Center (M. D. Anderson), less than 1% of patients with primary gastric carcinoma are found to have brain metastases. Little has been published regarding the evaluation and treatment of these patients. The purpose of this study was to review our experience with gastric cancer metastatic to the brain and to describe the efficacy of the treatment used. METHODS: Between 1957 and 1997, a total of 218,690 patients were seen for evaluation of malignant tumors at M. D. Anderson. Of these patients, 3320 (1.5%) had a diagnosis of gastric cancer; however, only 24 patients (0.7%) were found to have brain metastases on imaging studies or at autopsy. We performed a retrospective review of these 24 patients and divided them into three groups on the basis of the treatment they received. RESULTS: Group 1 included patients who received steroids alone (16 mg of dexamethasone, daily). Group 2 patients received 3000 cGy of whole-brain radiation therapy (WBRT) delivered in 10 fractions in addition to steroids. Group 3 patients were managed with surgical resection, WBRT, and steroids. There were 18 male and 6 female patients, with a median age of 53 years. The most common presenting symptoms were weakness, difficulty with balance, and headache. Of the 19 patients diagnosed antemortem, 11 patients developed neurological symptoms after the primary diagnosis of gastric carcinoma, whereas 8 patients developed neurological symptoms before the diagnosis of gastric cancer. Forty-five percent of patients had a single brain metastasis, whereas 55% had multiple lesions. All patients had systemic disease, with bone, liver, and lung involvement seen in 46%, 42%, and 29%, respectively. Nineteen of 24 patients received treatment after diagnosis of brain metastases. Four patients received steroids only (group 1), 11 patients received WBRT and steroids (group 2), and 4 patients were treated with surgery, WBRT, and steroids (group 3). Median survival was approximately 2 months for patients in groups 1 and 2, whereas group 3 patients had a median survival of slightly greater than I year. CONCLUSIONS: Our results suggest that the overall prognosis of patients with brain metastases from gastric cancer is extremely poor (median survival, 9 weeks). WBRT, as an adjuvant to steroid treatment, was not effective in improving outcome in our series. In selected patients, most of whom were relatively young and had less advanced systemic disease, surgical resection followed by WBRT was associated with relatively long survival times (median survival, 54 weeks).

Adenocarcinoma↗

Mitotic and post mitotic consequences of genomic instability induced by oncogenic Ha-ras.

Induced expression of a mutant human Ha-ras oncogene in NIH3T3 cells leads to the rapid production of multicentric chromosomes, acentric chromosome fragments, double minute chromosomes, increased heteroploidy, and increased capacity to undergo gene amplification. In this study we have used fluorescent-in-situ hybridization (FISH) to demonstrate that induction of the Ha-ras oncogene also leads to disruption of the mitotic machinery, resulting in aberrant mitoses and abnormal daughter cells. Cells induced to express an oncogenic Ha-ras transgene accumulate chromosomes that lag outside of the rest of the chromosomal architecture, chromosomes that form bridges between daughter nuclei at anaphase, and that form micronuclei. Many of these mitotic aberrations contain structurally abnormal chromosomes. These ras-induced changes were suppressed by the introduction of a gene encoding the dominant negative effector of ras, raf 301. Expression of raf301 in cells induced to express Ha-ras reduced the level of growth in soft agar, chromosome aberrations, mitotic aberrations, and frequency of gene amplification. These data provide evidence for an association between Ha-ras induced transformation, chromosome aberrations and gene amplification. Furthermore they offer insight into how the cell responds to the formation of aberrant chromosomes, and how disrupting chromosomal architecture could lead to further imbalances in the distribution of genetic material between daughter cells.

3T3 Cells↗

Epidemiology of group B streptococci: one year's experience in an obstetric and special care baby unit.

The epidemiology of group B streptococci (GBS) was studied in an obstetric unit and the related special care baby unit (SCBU). In 1 year 53 (77%) of 69 babies who acquired GBS from their mothers were colonized within 24 h of birth, compared with only 9 (35%) of 38 who acquired GBS from non-maternal sources. While 38 (36%) of 107 GBS colonized babies in the obstetric unit derived the organism from a non-maternal source, the value for the SCBU was only 2 (9%) of 23. In babies rectal and umbilical swabs gave the highest GBS isolation rates. Phage-typing and serotyping suggested that colonized mother baby pairs, rather than staff, were the primary source of hospital acquired GBS. This mode of GBS acquisition did not result in long-term carriage once babies had left hospital. Nosocomial transmission can play an important part in GBS epidemiology, but can be minimized by attention to infection control procedures.

Carrier State↗

Carriage and transmission of group B streptococci among STD clinic patients.

High rates of carriage of group B streptococci were found among men (38%) and women (42.3%) attending a clinic for sexually transmitted diseases. Swabs from the perineal/anorectal area gave the highest isolation rate and those from the urethra the lowest. The subpreputial sac was an important site for carriage of the organism, and there was a strong association between streptococcal isolation and balanitis. Of 92 couples studied, neither partner was colonised with group B streptococci in 36. In a further 36 one or other was colonised and in 20 both were colonised. Serotyping and phage typing showed that only three of these 20 couples were colonised with similar strains of the organism.

Carrier State↗

Colonisation of babies and their families by group B streptococci.

A high incidence of group B streptococcal disease of the newborn in West Berkshire led to a prospective study of the condition. Cultures taken from 1090 babies shortly after birth showed that 65 (6%) were colonised with the streptococcus. Thirty of these babies were assigned to group 1. Bacteriological samples were taken from babies and mothers at birth and at four, eight, and 12 weeks, and also from fathers and siblings. Fifty uncolonised babies and their families were similarly studied and served as controls (group 2). In group 1,28 of the 30 mothers and 14 of the 28 fathers examined were colonised by group B streptococci. In group 2 the streptococci were isolated from three babies, 12 mothers, and 11 out of 45 fathers during follow-up. These findings suggest that group B streptococci are carried predominantly in the lower gastrointestinal and genitourinary tracts. Most families are lightly colonised, but in others maternal colonisation is stable and heavy and the incidence of paternal colonisation high. Results of serotyping suggest that sexual transmission occurs, which may explain the difficulty in eradicating the organism during pregnancy.

Adult↗

Nosocomial transmission of group B streptococci.

The acquisition of group B streptococci by babies in a special-care baby unit and two postnatal wards was investigated over a six-month period using serology and phage typing. Sixty-three culture-positive babies were identified in the postnatal wards, one-third of whom had been born to mothers who were not carrying the organism in the genital tract or anorectal area during labour. A non-maternal source was identified for 14 of these 21 infants: either colonised mothers and babies in the same ward or, on one occasion, a member of the hospital staff. In the special-care baby unit, however, only one instance of nosocomial acquisition of group B streptococci was recorded despite a high prevalence of colonisation in the staff on the unit and the presence of heavily colonised babies. The results of this survey suggest that although sepsis caused by group B streptococci may be the result of nosocomial transmission, this may be prevented by careful attention to hygiene.

Cross Infection↗

Transmission of group B streptococci. Traced by use of multiple epidemiologic markers.

During a three-week period, septicemia caused by group B Streptococcus, serotype III, developed in four infants born at a community hospital. The first infant had early-onset disease; late-onset disease that appeared, from epidemiologic data, to be nosocomial developed in the other three infants. Bacteriophage typing and antimicrobial susceptibility testing confirmed the relatedness of the isolates. A prospective study designed to differentiate between vertical and nosocomial transmission of group B Streptococcus showed that of 82 infants, 21 (26%) were culture-positive during their hospitalization, and nine of these infants (43%) had been culture-negative at birth. Although serotype III strains were recovered from four of nine infants with apparently nosocomial acquisition, none of the isolates displayed an antibiogram or bacteriophage type similar to that of the isolates involved in the recent cluster. Bacteriophage typing and antimicrobial susceptibility testing in addition to the use of serotyping may be helpful in epidemiologic studies of group B Streptococcus.

Bacteriological Techniques↗

Source of group B streptococci in the female genital tract.

Swabs were taken from the posterior fornix, perineum, and anorectum of 135 patients on three occasions during their pregnancy. Multiple isolates of beta-haemolytic streptococci of group B were obtained from 24 women, in 21 of whom the strains were examined by a highly discriminative serotyping and phage typing method. In 18 of these patients their own isolates were indistinguishable but different from those of other women with multiple isolates. Women yielding group B streptococci from the posterior fornix usually carried an indistinguishable strain in the anorectum.

Anal Canal↗