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Biomedical subjects

S Williams

Publications and source records attributed to S Williams.

At least 397 records · Page 22Linked to original sources
PubMed1996

Role of renal nerves in mediating the hypertensive effects of nitric oxide synthesis inhibition.

Recent studies suggest that enhanced renal sympathetic nervous activity plays an important role in mediating the renal hemodynamic and electrolyte excretion changes associated with acute inhibition of NO synthesis. The purpose of this study was to determine the importance of renal nerves in mediating the long-term hypertensive and renal actions of NO synthesis blockade. To achieve this goal, we infused N(G)-nitro-L-arginine methyl ester (L-NAME) at a rate of 25 microg/kg per minute for 2 weeks in control dogs and in bilaterally renal-denervated dogs. NO synthesis blockade in control dogs increased arterial pressure by 18%, from 94 +/- 3 to 111 +/- 4 mm Hg, and decreased heart rate from 74 +/- 4 to 57 +/- 4 beats per minute (bpm). L-NAME also decreased renal plasma flow from 195 +/- 18 to 166 +/- 18 mL/min while having no effect on glomerular filtration rate (67 +/- 7 versus 63 +/- 6 mL/min). In the renal-denervated dogs, inhibition of NO synthesis increased arterial pressure by 14%, from 92 +/- 4 to 105 +/- 5 mm Hg, and decreased heart rate from 80 +/- 4 to 65 +/- 5 bpm. Renal plasma flow in this group decreased from 195 +/- 20 to 165 +/- 20 mL/min, whereas glomerular filtration rate remained unchanged (66+/- 6 versus 64 +/- 6 mL/min). In addition, renal excretion of sodium and water in response to L-NAME was similar in each group. The results of this study indicate that the long-term hypertensive and renal effects of NO synthesis inhibition in the dog are not dependent on activation of the renal sympathetic nervous system.

Animals↗
PubMed1996

An analysis of telephone calls to an inner-city accident and emergency department.

The general public in the UK often telephone accident and emergency (A&E) departments for medical advice. Such calls are usually dealt with by nursing staff in an informal manner (often with no written record of the call being made). The specific questions addressed in this study are who was calling for advice, when did they call, what were their presenting complaints, and what was the outcome of the call? In addition, the study provided an opportunity to test the implementation of a new system of record-keeping for telephone consultation. A telephone consultation record (TCR) was developed and used to record details of each call made to the A&E department for medical/health advice. An analysis of 597 consecutive documented calls is presented in this paper. The majority of calls were dealt with by 'E' grade nursing staff (42.7%); only four calls (0.7%) were recorded by medical staff. Two hundred and six (43.5%) calls related to patients aged up to 15 years. In 57% of the cases the call was made by a third party. In all, 149 different presenting complaints were recorded on the TCRs. The three most common presenting complaints were dental problems (7.4%), fever (4.3%), and concerns about drug reactions (23%). Seventy-three per cent of callers were advised that a visit to the A&E department was not immediately necessary. The study identifies several important issues for development of a more formal and effective system of telephone advice. The majority of calls made to the A&E department appeared to be of a primary care nature but the extent to which nurses are trained to assess and advise on these problems needs to be questioned. A reluctance to document the calls to A&E was identified, one reason being a concern about accountability. Training and support are clearly required.

Adolescent↗
PubMed1996

Glutathione S-transferase M1 genotype and age-related cataracts. Lack of association in an Italian population.

PURPOSE: To investigate possible associations between the gene number and allelic forms of glutathione S-transferase M1 (GSTM1) and the occurrence of nucleic and cortical age-related cataracts. METHODS: Patients with cortical cataract, nuclear cataract, mixed and cortical cataract, and no cataract were sytematically selected from subjects evaluated in the Italian-American Study of the Natural History of Age-Related Cataract. The patients were typed for the A, B, and null alleles of GSTM1 using a variation of the amplification refractory mutation system. RESULTS: Forty-nine percent of patients (50/102) with cortical cataracts, 45% (13/29) with nuclear cataracts, 51% (36/71) with mixed nuclear and cortical cataracts, and 50% of controls (49/98) were homozygous for the null GSTM1 allele. Twenty-five percent of patients (26/102) with cortical cataracts, 24% (7/29) with nuclear cataracts, 31% with mixed nuclear and cortical cataracts, and 27% of controls (26/98) displayed only the A allele for GSTM1. Twenty-four percent of patients (24/102) with cortical cataract, 24% (7/29) with nuclear cataracts, 14% (10/71) with mixed nuclear and cortical cataract, and 18% of controls showed only the B allele for GSTM1. Two percent of patients (2/102) with cortical cataracts, 7% (2/29) with nuclear cataracts, 4% (3/71) with mixed nuclear and cortical cataracts, and 5% of controls (5/98) showed both A and B alleles for GSTM1. CONCLUSIONS: No associations between the GSTM1 alleles, including the null allele, and cataracts were detected in this study.

Aged↗
PubMed1996

The gyrification of mammalian cerebral cortex: quantitative evidence of anisomorphic surface expansion during phylogenetic and ontogenetic development.

Describing the shapes of 3D objects has proved to be as problematical in biology as in other areas. In an attempt to tackle this problem, established stereological methods (the Cavalieri principle and vertical sectioning) have been used to estimate a 3D shape-dependent quantity which can detect anisomorphic changes and is related to the degree of cortical convolution or gyrification. This isomophy factor is employed to assess phylogenetic and ontogenetic changes in the mammalian cerebral cortex. Gross anatomical differences between cerebral hemispheres of adult domestic mammals (horses, oxen, pigs, goats, dogs, cats and rabbits) were tested by paying attention to species, laterality and sex differences. Human fetal brains were also studied. Mean body weights of domestic mammals varied from 4 kg to 460 kg and brain weights from 10 g to 636 g. Fetuses weighed 39-610 g (crown-rump lengths 85-185 mm) and brain volumes were 4-56 cm3. Isomorphy factors were derived from estimates of hemisphere volumes and cortical surface areas. Hemisphere shape varied between species but no lateral or sex differences were detected. It is concluded that these mammalian brains are, in terms of their gross anatomy, symmetric and not sexually dimorphic. Fetal brains became more convoluted during uterine development. The isomorphy factor offers a convenient measure of gyrification which demonstrates that brains become more convoluted as they enlarge.

Animals↗
PubMed1996

Cocaine-associated rhabdomyolysis causing renal failure in pregnancy.

BACKGROUND: Cocaine use is known to have multisystemic effects. Recently, acute renal failure as a result of rhabdomyolysis has been described as a complication of cocaine use. During pregnancy, cocaine is associated with abruptio placentae. A patient presenting with both complications is described. CASE: A 25-year-old multiparous woman at 34 weeks' gestation developed abruptio placentae approximately 18 hours after using cocaine alkaloid. Six hours later, a cesarean delivery was performed after she presented with vaginal bleeding and fetal bradycardia. Oliguria was present from admission and persisted despite aggressive fluid hydration, dopamine infusion, and intravenous administration of furosemide. Serum creatinine phosphokinase and urine myoglobin were both elevated at 558 IU/L and 432 ng/mL. Hemodialysis was required for presumed cortical necrosis. CONCLUSION: Rhabdomyolysis, as indicated by elevated creatinine phosphokinase and the presence of myoglobin in the urine, suggests that nephrotoxicity from myoglobinuria may contribute to acute renal failure in cases of cocaine mediated abruptio placentae.

Abruptio Placentae↗
PubMed1996

DEXA supports the use of BMI as a measure of fatness in young girls.

OBJECTIVE: To examine the relationship of body fat mass measured by dual energy X-ray absorptiometry (DEXA) to BMI in young girls, according to age and normative BMI percentile groupings. DESIGN: Cross-sectional observation study. SETTING: Dunedin, an urban town in the South Island of New Zealand. SUBJECTS: 196 healthy Caucasian girls aged 4-16 y. MEASUREMENTS: Body weight, height and BMI, total fat mass and % body fat (by DEXA). RESULTS: Our BMI percentile standard groupings were < 5 centile (n = 7); 5-50 centile (n = 71); 51-75 centile (n = 50); 76-90 centile (n = 42); 91-95 centile (n = 12); > 95 centile (n = 14). In this whole population sample DEXA-derived fat mass correlates well with BMI (n = 0.934) indicating that BMI accounts for 87.2% of the variance in body fat mass. However, at the extremes of BMI the association is weaker. A nomogram for predicting DEXA fat mass from BMI in girls is presented. CONCLUSION: Because DEXA-derived fat mass correlates well with BMI throughout the 'normal' range of BMI (5-95th centiles) our study supports the usefulness of BMI as a simple measure of fatness in girls. Children with BMI values outside the normal BMI range may benefit from more exact body composition assessment using DEXA.

Absorptiometry, Photon↗
PubMed1996

Cutaneous tuberculous abscess: a management problem.

A 66-year-old woman presented with a 6-week history of an indolent ulcerating lesion on the anterior chest wall. She had a past medical history of pulmonary tuberculosis which had been treated successfully in 1947. Biopsy of the ulcer showed granulomas and acid-fast bacilli. Cultures grew Mycobacterium tuberculosis, sensitive to all antituberculous drugs. After 7 months of treatment with isoniazid and rifampicin, there was little sign of healing. A sinogram showed a fistula leading into the plombage mass in the left upper lobe. Surgery to remove the plombage and excise the fistula was planned but was rejected by the patient as the risks of this operation are considerable. With continued antituberculous medication the discharge has reduced although the ulcer has not healed.

Abscess↗
PubMed1995

A community survey of sun exposure, sunburn and sun protection.

AIM: To describe outdoor activities, sun protection behaviours and the experience of sunburn in a sample of New Zealanders during summer weekends of 1994. METHODS: 1243 respondents to a telephone survey provided information regarding their outdoor activities for the 5 hour period around midday of the previous Saturday and Sunday. The sample was drawn from those aged 15 to 65 years in the five centres of Auckland, Hamilton, Wellington, Christchurch and Dunedin. Respondents provided information on sun exposure, sunburn, sun protection and beliefs about tanning, as well as background demographic information, skin type and previous experience of sunburn. RESULTS: 12% of the sample (or 17% of all those outdoors) reported being sunburned on the preceding weekend, and those sunburned tended to be men, and to be under age 35 years. The face, neck and limbs were the areas most frequently reported as burned. Sporting activities and beach or water activities were associated with the highest number of episodes of burning. Overall 38% of those outside reported wearing a hat and 32% reported the use of a sunscreen. Positive attitudes to tanning were quite common and probably present the main target for change in the community. CONCLUSION: On any sunny weekend in summer about three-quarters of adult New Zealanders will be out in the sun for relatively long periods of time, and many will get sunburned. The reduction of such harmful sun exposures remains an important public health goal.

Adolescent↗
PubMed1995

A novel serum protein similar to C1q, produced exclusively in adipocytes.

We describe a novel 30-kDa secretory protein, Acrp30 (adipocyte complement-related protein of 30 kDa), that is made exclusively in adipocytes and whose mRNA is induced over 100-fold during adipocyte differentiation. Acrp30 is structurally similar to complement factor C1q and to a hibernation-specific protein isolated from the plasma of Siberian chipmunks; it forms large homo-oligomers that undergo a series of post-translational modifications. Like adipsin, secretion of Acrp30 is enhanced by insulin, and Acrp30 is an abundant serum protein. Acrp30 may be a factor that participates in the delicately balanced system of energy homeostasis involving food intake and carbohydrate and lipid catabolism. Our experiments also further corroborate the existence of an insulin-regulated secretory pathway in adipocytes.

3T3 Cells↗
PubMed1995

Quantitative structure-activity relationships (QSARs) of N-terminus fragments of NK1 tachykinin antagonists: a comparison of classical QSARs and three-dimensional QSARs from similarity matrices.

The ability of three-dimensional quantitative structure-activity relationships (QSARs) derived from classical QSAR descriptors and similarity indices to rationalize the activity of 28 N-terminus fragments of tachykinin NK1 receptor antagonists was examined. Two different types of analyses, partial least squares and multiple regression, were performed in order to check the robustness of each derived model. The models derived using classical QSAR descriptors lacked accurate quantitative and predictive abilities to describe the nature of the receptor-inhibitor interaction. However models derived using 3D QSAR descriptors based on similarity indices were both robust and significantly predictive. The best model was obtained through the statistical analysis of molecular field similarity indices (n = 28, r2 = 0.846, r(cv)2 = 0.737, s = 0.987, PRESS = 7.102) suggesting that electronic and size-related properties are the most relevant in explaining the affinity data of the training set. The overall quality and predictive ability of the models applied to the test set appear to be very high, since the predicted affinities of three test compounds agree with the experimentally determined affinities obtained subsequently within the experimental error of the binding data.

Carbamates↗
PubMed1995

Patterns of failure following high-dose chemotherapy and autologous bone marrow transplantation with involved field radiotherapy for relapsed/refractory Hodgkin's disease.

PURPOSE: To evaluate the patterns of failure and outcome of patients undergoing high-dose chemotherapy and autologous bone marrow transplantation for relapsed/refractory Hodgkin's disease with emphasis on the impact of involved-field radiotherapy. METHOD AND MATERIALS: Fifty-four adult patients with refractory (25) or relapsed (29) Hodgkin's disease underwent high-dose chemotherapy with either autologous bone marrow (32) or peripheral stem cell (23) transplantation. Twenty patients received involved-field radiotherapy either prior to (7) or following (13) high-dose chemotherapy. Patients treated prior to the high-dose chemotherapy received radiation to bulky or symptomatic sites, and those treated following the transplantation were treated to sites of disease persistence (10) or to consolidate a complete response (3). Twenty-six patients had purely nodal disease, 10 had lung involvement, 7 liver, 5 bone, and 3 bone marrow. A total of 147 sites were present prior to high-dose chemotherapy. Nineteen were bulky (> or = 5 cm), and 42 arose in a previous radiotherapy field. RESULTS: Twenty-five of the 54 patients (46.3%) relapsed. Seventeen (68.0%) relapsed in sites of disease present prior to high-dose chemotherapy. Patients treated with involved-field radiotherapy had a lower rate of relapse in sites of prior disease involvement (26.3 vs. 42.8%) (p < 0.05) than those not treated with radiotherapy. Twenty-one patients had disease persistence following high-dose chemotherapy, of which 10 received involved-field radiotherapy and were converted to a complete response. Patients with disease persistence who received involved-field radiotherapy had a better progression-free survival (40.0 vs. 12.1%) (p = 0.04) than those who did not. Moreover, the patients converted to a complete response had similar progression-free and cause-specific survival as those patients achieving a complete response with high-dose chemotherapy alone. Of the initial 147 sites, 142 (97.3%) were amenable to involved-field radiation therapy. The addition of involved-field radiotherapy improved the 5-year local control of all sites (p = 0.008), nodal sites (p = 0.01), and sites of disease persistence (p = 0.0009). CONCLUSIONS: Patients with relapsed/refractory Hodgkin's disease undergoing high-dose chemotherapy and autologous bone marrow rescue have a high rate of relapse in sites of prior disease involvement. Involved-field radiotherapy is capable of improving the control of these sites, the majority of which are amenable to radiotherapy. In addition, the use of radiotherapy to sites of disease persistence following high-dose chemotherapy may improve the outcome of these patients.

Adult↗