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Biomedical subjects

S A Wilson

Publications and source records attributed to S A Wilson.

At least 55 records · Page 3Linked to original sources
PubMed1995

Transcriptional analysis of the amidase operon from Pseudomonas aeruginosa.

The transcriptional start point for the amidase structural gene (amiE) of Pseudomonas aeruginosa has been identified, and the promoter (pE) has been shown to function constitutively, as predicted for a system regulated by transcription antitermination. Northern (RNA) analysis results show that in cells grown under inducing conditions, a major 1.3-kb amiE transcript arises from pE, and in addition, a larger transcript of approximately 5.0 kb in length has been shown to derive from the same promoter, encoding all of the genes of the operon. DNA sequencing and S1 nuclease mapping have located a transcription terminator downstream of amiE, which terminates approximately half of the pE transcripts. Previously, two RpoN-dependent promoter-like sequences (pN1 and pN2) were identified upstream of the negative regulator gene, amiC, and we have now constructed a promoter probe vector which shows weak constitutive promoter activity within this region. This promoter would be expected to provide basal levels of expression of the amiC and amiR regulatory genes to allow induction of the system.

Amidohydrolases↗
PubMed1995

Another view of Medicare HMOs: not always what the doctor ordered. Interview by Meg Matheny.

Sally Hart Wilson is one of several lawyers who, on behalf of the Center for Medicare Advocacy, have filed a class-action suit seeking better protections for Medicare beneficiaries in HMOs. The experience of the lead plaintiff (one of 15) in Grijalva v. Shalala illustrates the down side of Medicare HMOs, says Ms. Wilson. Grigoria Grijalva, 71, an enrollee with diabetes, hypertension, congestive heart failure, anemia, and a uremic bladder, complained to her physician about pain in her foot. But the physician's treatment was inadequate, the complaint alleges, and as a result her right leg was amputated. In subsequent years, the lawsuit says, the HMO denied necessary skilled nursing home days and skilled home health services and never sent a notice of denial or a description of her appeal rights, as Medicare requires.

Aged↗
PubMed1994

Lack of peroxisome proliferation in marmoset liver following treatment with ciprofibrate for 3 years.

The effect of treatment of marmosets with ciprofibrate for 3 years on activities of hepatic enzymes, hepatic histomorphology, and ultrastructure were investigated. Male and female marmosets were dosed with ciprofibrate (2, 10, and 20 mg/kg) by oral gavage once daily for 3 years. No effect on liver weight (adjusted for body weight) or liver morphology was observed. The activities of catalase, glutathione peroxidase, alpha-glycerophosphate dehydrogenase, benzphetamine N-demethylase, and ethoxyresorufin O-deethylase were unaffected by treatment with ciprofibrate. Activity of glutathione transferase was increased in the low dosage group but unaffected in the mid and high dosage groups. Modest increases in activities of peroxisomal beta-oxidation (2.5-fold, maximal), carnitine acetyl transferase (1.7-fold, maximal), and carnitine palmitoyl transferase (2-fold, maximal) were observed. Cytochemical staining and quantitative image analysis failed to indicate any effect on peroxisomal number, size, or volume density. Similarly, there was no increase in lipofuscin deposition. This study provides data on the effects of a potent peroxisome proliferator on primate liver following a dosing period much greater than that used in previously published studies and is further evidence that the marmoset is relatively insensitive to the well-documented effects that ciprofibrate and other peroxisome proliferators have on rat liver.

Animals↗
PubMed1994

Information needs prior to breast biopsy.

Biopsy is the definitive diagnostic procedure for breast cancer. The fear of cancer may make the breast biopsy itself a distressing experience for women and their significant others. Information seeking is believed to be a primary mode of coping with distressful events. The purpose of this study was to describe the information needs of women and their significant others prior to a breast biopsy and to explore the influence of information on the breast biopsy experience. Semi-structured, audiotape-recorded interviews with 11 women and 8 significant others were conducted prior to breast biopsy, and categories arising from the data were developed. The primary information need identified by the participants was to know "Is it cancer?" Participants' uncertainty regarding the outcome of the biopsy led to feelings of distress. The major strategy used to reduce distress was information management, in which the amount and type of incoming information was controlled. Nursing interventions based on the study findings are presented.

Adult↗
PubMed1993

Topography of excitatory and inhibitory muscle responses evoked by transcranial magnetic stimulation in the human motor cortex.

Transcranial magnetic stimulation of the motor cortex produces a motor-evoked potential (MEP) in the electromyogram followed by a silent period (SP) which is thought to be due to cortical inhibition. In this study, the topography and size of the cortical areas from which an MEP and SP are evoked in the abductor pollicis brevis muscle (APB) of the hand were compared. The SP area was found to be large, encompassing and surrounding the MEP area. These findings infer the existence of an inhibitory surround limiting the excitatory area for APB in the human motor cortex.

Adult↗
PubMed1993

Antitermination of amidase expression in Pseudomonas aeruginosa is controlled by a novel cytoplasmic amide-binding protein.

Amide-inducible expression of the aliphatic amidase system of Pseudomonas aeruginosa can be reconstituted in Escherichia coli with only the amidase structural gene amiE, the negative regulator amiC and the positive regulator amiR, a transcription antitermination factor. Complementation experiments in E. coli suggest that negative control of amidase expression by AmiC is mediated by a protein-protein interaction with AmiR. Purified AmiC binds acetamide with a KD of 3.7 microM in equilibrium dialysis studies, and therefore AmiC appears to be the sensory partner of the AmiC/AmiR pair of regulatory proteins, responding to the presence of amides. Sequence analysis techniques suggest that AmiC is a member of the structural family of periplasmic binding proteins, but has a distinct and novel cytoplasmic role.

Amidohydrolases↗
PubMed1993

Transcranial magnetic stimulation mapping of the motor cortex in normal subjects. The representation of two intrinsic hand muscles.

The TMS-mapped representations of two intrinsic hand muscles, abductor pollicis brevis (APB) and abductor digiti minimi (ADM), were quantified using a transcranial magnetic stimulation (TMS) mapping technique in 10 right handed and 6 left handed subjects. A 50 mm diameter figure eight coil was used. Stimulus sites were located using a latitude/longitude based coordinate system, stimulus intensity was threshold-adjusted and stimuli were applied during controlled low-level (10%) voluntary contraction of the target muscles. Maps of the corticomotor representation were generated by fitting a continuously defined three dimensional function to the data obtained from stimulation at specific scalp sites, and projecting this function onto a two dimensional surface using a radial projection. It was found that the mapped representations of APB and ADM were large and overlapping but that there was a statistically significant separation of the two areas, the APB area being more laterally placed than the ADM area. The TMS-mapped representations of the two muscles showed no significant interhemispheric differences and were similar in left and right handed subjects. Rotation of the magnetic coil through 90 degrees resulted in medial shift and elongation of the TMS-mapped representations but there was no change in the relative positions of the two areas. The TMS-mapped representations were found to be very reproducible when mapping was repeated after intervals of up to 181 days. The present technique of TMS mapping allows the representation of individual hand muscles in the primary motor cortex to be reliably and reproducibly mapped and should prove useful for further studies of the physiology and pathophysiology of the motor cortex in man.

Adult↗
PubMed1993

The muscle silent period following transcranial magnetic cortical stimulation.

Transcranial magnetic stimulation (TMS) of the motor cortex during tonic muscle contraction produces a motor evoked potential followed by a silent period in the electromyogram. We sought to characterize the TMS induced silent period and to compare it to the silent period induced by supramaximal peripheral nerve stimulation. TMS was delivered to the motor cortex using a 9 cm diameter circular coil and the surface electromyogram was recorded from the contralateral abductor pollicis brevis muscle in six normal subjects. Increasing TMS stimulus intensity from 10 to 50% above threshold resulted in an increase in the duration of the silent period from a mean of 50 ms to 185 ms. Increasing the level of tonic muscle contraction from 5% of maximum to maximum resulted in a decrease in silent period duration from a mean of 155 ms to 133 ms. In contrast, the duration of the silent period following supramaximal median nerve stimulation showed greater shortening under similar conditions, from a mean of 160 ms at 5% of maximum contraction to 99 ms at 75% of maximum contraction. The TMS induced silent period was present during a TMS induced increase in the reaction time for a ballistic movement, the onset of movement being delayed until the end of the silent period. Peripheral nerve stimulation did not produce a delay in movement onset. The present findings favour a cortical origin for the TMS induced silent period, probably on the basis of intracortical inhibition, rather than peripheral inhibition of spinal motoneurones which is considered to be the basis for the silent period following peripheral nerve stimulation.

Adult↗
PubMed1993

Direct inoculation of food as the cause of an outbreak of group A streptococcal pharyngitis.

An investigation was conducted of a food-related outbreak of group A streptococcal pharyngitis following an elementary school banquet. Of 166 surveyed banquet attendees, 71 (43%) reported outbreak-associated pharyngitis, and 21 (88%) of 24 tested attendees had evidence of group A streptococcus (GAS) in the throat. Attendees who ate macaroni and cheese were three times more likely to develop pharyngitis than those who did not (66/132 [50%] vs. 5/30 [17%], P = .002). None of the food handlers had GAS recovered by throat culture. However, the cook who prepared the macaroni and cheese had a hand wound; a wound culture grew GAS with the same T agglutination pattern and M- and/or opacity factor type as that of all available GAS strains from ill attendees. Under laboratory conditions, macaroni and cheese supported rapid growth of the outbreak-associated strain of GAS. To the authors' knowledge, this is the first documented foodborne outbreak of GAS pharyngitis in which the only apparent source of contamination was a food handler's skin lesion.

Disease Outbreaks↗
PubMed1993

Hospice and Medicare benefits: overview, issues, and implications.

Hospice care is based on a holistic philosophy that considers the physical, psychological, and spiritual dimensions of care for dying patients and their families. It is a family-centered approach and promotes death with dignity. The rapid growth of the hospice movement was in response to dissatisfaction with the care of the terminally ill and demands for death with dignity. Public support for the hospice was so strong that just 8 years after the first hospice was founded, it became a benefit under Medicare. The Medicare hospice benefit emphasizes home care and has shifted the burden of care to families. The restrictive nature of Medicare hospice rules influences who is eligible for hospice care. The Medicare benefit is not congruent with the holistic philosophy of hospice.

Eligibility Determination↗
PubMed1992

An outbreak of hepatitis A associated with swimming in a public pool.

A multistate outbreak of hepatitis A was traced to a campground in Louisiana. Among 822 campers during one weekend, 20 developed hepatitis A. Case-patients ranged in age from 4 to 36 years; the highest attack rate (6.4%) was for children aged 5-9 years. A case-control study revealed that case-patients were more likely than controls to have swum in a public swimming pool on Saturday afternoon (19/19 vs. 26/38; odds ratio [OR], undefined; lower 95% confidence limit, 1.7). Case-patients were more likely than controls to have swum in the jacuzzi pool (16/19 vs. 10/26; OR, 8.0; 95% confidence interval, 1.5-47.1) or adult pool A (19/19 vs. 15/26; OR, undefined; lower 95% confidence limit, 2.6). Case-patients were also more likely to have swum for greater than 1 h and to have put their heads under the water. Because of the design of the filtering system of adult pool A, a cross-connection between a sewage line and the pool water intake line was possible. This outbreak may have been caused by transmission of hepatitis A through swimming; thus, swimming may serve as a mode of transmission of hepatitis A virus, especially among small children.

Adolescent↗
PubMed1991

Crystallization of and preliminary X-ray data for the negative regulator (AmiC) of the amidase operon of Pseudomonas aeruginosa.

The negative regulator (AmiC) of the amidase operon of Pseudomonas aeruginosa has been purified from an over-expressing clone and crystalized. Crystals of diffraction quality were obtained from polyethylene glycol 4000 and ammonium sulphate. AmiC crystallizes in P4(2)2(1)2 (a = 104.4 A, c = 66.6 A) with one subunit in the asymmetric unit. Crystals diffract beyond 2.8 A.

Amidohydrolases↗
PubMed1991

Changes in cochlear sensitivity do not alter relative thresholds of different spontaneous rate categories of primary auditory nerve fibres.

The CF thresholds of three different spontaneous firing rate categories of single auditory nerve fibres were measured in guinea pigs with widely differing cochlear sensitivities. The CF thresholds for all fibres were compared to the CAP thresholds at the same frequencies. The relationship between single fibre CF threshold and CAP thresholds for the three different fibre categories remained unchanged despite the very wide range of absolute CAP thresholds. The widely ranging CAP thresholds in these animals were probably due to varying degrees of outer hair cell pathology and these data therefore support the notion that in normal animals, the origin of differences in threshold between fibres with different spontaneous rates, lies in the properties of the inner hair cells and/or their synapses with afferent dendrites.

Action Potentials↗
PubMed1990

SO2-induced growth reductions and sulphur accumulation in wheat.

Ten open-top chambers were used to obtain SO(2) concentration-response relationships for growth in wheat cv. Banks, and to study the associated sulphur accumulation. Two-week-old seedlings were exposed to 0.004, 0.042, 0.121, 0.256 or 0.517 microl litre(-1) SO(2) for 79 days, 4 h per day. Response variables measured included height, shoot weight, development stage, tiller number, ear weight per plant, average ear weight, total ear number and shoot sulphur concentration. All growth parameters were significantly negatively affected by SO(2) concentrations above and including 0.042 microl litre(-1). A highly significant positive correlation existed between shoot sulphur concentration and ambient SO(2) concentration.

Journal Article↗