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Biomedical subjects

D Roberts

Publications and source records attributed to D Roberts.

At least 145 records · Page 8Linked to original sources
PubMed1996

Basal cell carcinomas cause little handicap.

Basal cell carcinoma (BCC) is the most common type of skin cancer and the incidence of BCC is expected to rise, with increased demand on dermatology resources. Little is known of the effect on people's lives of having skin cancer. The aim of this study was to quantify the handicap caused gy basal cell carcinomas before and after therapy. Forty-four patients (22 males, mean age = 65 yrs, range = 35-81 yrs) with 48 BCCs were recruited and 37 patients completed the study. Each patient completed the UK Sickness Impact Profile (UKSIP) and the Dermatology Life Quality Index (DLQI) at the initial visit to the dermatology clinic, 1 week after treatment and 3 months after treatment. Lesions had been present for a mean of 25 months (range = 1-240 months), their mean diameter was 9.6mm (range = 3-35mm) and the sites were head and neck (79%), trunk (17%) and limbs (4%). There was no relationship between the quality of life score and size of lesion. Overall the scores at presentation were very low, rising 1 week after treatment and falling to below the initial scores at 3 months (mean UKSIP 0.4%, 0.7%, 0.13%; mean DLQI 5.3% 8.7%, 1.2%). BCCs cause little handicap. This may explain the delay in seeking medical attention and should be considered in planning public health education about BCCs.

Adult↗
PubMed1996

Proprioception in the nearly extended knee. Measurements of position and movement in healthy individuals and in symptomatic anterior cruciate ligament injured patients.

Proprioception of the knee was measured in 19 healthy individuals to evaluate whether there were any differences between extension and flexion movements from two different starting positions. The threshold before detecting a passive movement, visual estimation on a protractor of a passive change in position (30 degrees angular change) and active reproduction of the same angular change were registered. The reference population was tested twice to study normal variation and reproducibility, followed by the evaluation of 20 patients with chronic, symptomatic and unilateral anterior cruciate ligament (ACL)-deficient knees. In the normal population no differences were found between the right and the left leg, men and women, or measurements made at the first and at the second test occasion. The thresholds from a starting position of 20 degrees were lower for extension than for flexion. When comparing the thresholds for extension between the 20 degrees and the 40 degrees starting position, lower values were found in the more extended position. The thresholds for flexion were lower from the 40 degrees starting position than from the 20 degrees starting position. The active reproduction of an angular change of 30 degrees was more accurate during flexion (30 degrees-60 degrees) than during extension (60 degrees-30 degrees). There were no differences in the reproduction tests or in thresholds from the 40 degrees starting position between the patients and the normal group, but the patients had higher thresholds from the 20 degrees starting position, in movements towards both extension 1.0 degree (range 0.5 degree-12.0 degrees) and flexion 1.5 degrees (range 0.5 degree-10.0 degrees) than the normal group 0.75 degree (range 0.5 degree-2.25 degrees) (P = 0.01) and 1.0 degree (range 0.5 degree-3.0 degrees) (P = 0.06), respectively. Thus, information of passive movements in the nearly extended knee position was more sensitive towards extension than towards flexion in threshold tests and the sensitivity improved closer to full extension, which implies a logical joint protective purpose. In this nearly extended knee position, which is the basis for most weight-bearing activities, patients with symptomatic ACL-deficient knees had an impaired awareness in detecting a passive movement. There were no differences in the more flexed position or in the reproduction tests between the patients and the normal group, and reproduction tests in the present form seem less appropriate to use in the evaluation of ACL injuries.

Adult↗
PubMed1996

Improving analgesic prescribing in a general teaching hospital.

Patients suffering from cancer and human immunodeficiency virus (HIV) disease at a teaching hospital were found to have poorly controlled pain. Many were prescribed inappropriate analgesia. A palliative care service was established to provide symptom control for patients and education for staff. Educational materials were developed, didactic teaching organized, and one-to-one education by case discussion provided to improve patient management. A repeat survey to evaluate the service showed an increase in the use of appropriate opioids, such as morphine and diamorphine, and a decrease in the use of buprenorphine and papaveretum, which are less suitable for use in chronic cancer pain. The acceptability of the guidelines and rapid availability of a palliative care opinion has improved analgesic prescribing.

Adolescent↗
PubMed1996

Glubodies: randomized libraries of glutathione transferase enzymes.

BACKGROUND: The immunoglobulin framework has been mutagenized to engineer recombinant libraries of proteins as potential diagnostics and novel catalysts, although the often shallow binding cleft may limit the utility of this framework for binding diverse small organic molecules. By contrast, the glutathione S-transferase (GST) family of enzymes contains a deep binding cleft, which has evolved to accommodate a broad range of hydrophobic xenobiotics. We set out to determine whether GST molecules with novel ligand-binding characteristics could be produced by random mutagenesis of segments of the binding cleft. RESULTS: We have identified two ligand-recognition segments (LRSs) in human GST P1, which are near the active site in the folded protein, but have characteristics indicating that the integrity of their sequence is not essential for the overall structure or activity of the protein. Libraries of GST P1-derived proteins were produced by substituting randomized sequences for an LRS or inserting random sequences into an LRS. The recombinant proteins in the libraries, collectively designated as 'glubodies,' generally retain enzymatic activity but differ markedly both from each other and from the parent enzyme in sensitivity to inhibition by diverse small organic compounds. In some instances, a glubody is inhibited by completely novel structures. CONCLUSIONS: We have shown that a non-antibody framework can be used to create large libraries of proteins with a wide range of binding specificities for small organic molecules. The glubodies provide a rich source of data for correlating the structural and functional features of proteins relevant to ligand binding. The criteria applied for identifying an LRS in GST P1 are generally applicable to other protein frameworks.

Amino Acid Sequence↗
PubMed1996

Peritonitis, functional catheter loss and the sitting of the Dacron cuff in chronic peritoneal dialysis catheters in children.

Functional peritoneal dialysis catheter loss due to persistent or recurrent peritonitis is a common clinical problem in paediatric patients. To examine the effect of positioning of the cuff on infection and loss rate we compared catheters where the cuff was buried in the rectus sheath (deep cuffs) with those where the cuff was sutured to the external oblique muscle, just below the subcutaneous fascia (superficial cuffs). Of 62 catheters inserted into 35 patients (median age 7.76 yrs, range 0-17 yrs) 28 were lost through peritonitis of which 19 (68%) were due to Staph. aureus infection, usually associated with exit site colonisation or infection. 12 out of 20 catheters with superficial cuffs were lost through infection compared with 16 out of 42 with deep cuffs (relative risk reduction 37%, p = ns). Controlling for patient age and infecting organism made no difference to this statistic. 15 out of 21 catheters inserted into patients < 2yrs of age were lost through peritonitis compared to 13 out of 41 catheters inserted into patients over 2 yrs of age (p = 0.037). We conclude that although siting of the Dacron cuff in the rectus sheath is somewhat protective against penetrating infection this is still a major problem in the infant and young child where alternative strategies for the prevention of Staph. aureus infection need to be sought.

Adolescent↗
PubMed1996

Prevalence and significance of implantation site trophoblastic atypia in hydatidiform moles and spontaneous abortions.

The authors studied the prevalence and significance of implantation site trophoblastic atypia in hydatidiform moles and spontaneous abortions. Three pathologists independently categorized 99 early abortion specimens regarding diagnosis (spontaneous abortion, partial hydatidiform mole, complete hydatidiform mole); qualitative atypia of implantation site trophoblast (absent, mild, moderate-severe); and quantitative atypia of implantation site trophoblast (absent, focal, diffuse). Interobserver agreement was good to excellent regarding diagnosis (kappa 0.66-0.79) and poor to fair regarding qualitative atypia of implantation site trophoblast (kappa 0.20-0.43). By consensus diagnosis, implantation site trophoblastic atypia was mild and focal in 5% of 22 spontaneous abortions; predominantly focal in 40% of 30 partial moles (33% mild atypia; 7% moderate-severe atypia); and, predominantly diffuse in 87% of 47 complete moles (21% mild atypia; 66% moderate-severe atypia). Among hydatidiform moles, the subsequent development of persistent gestational trophoblastic tumor did not relate to the degree of implantation site trophoblastic atypia. The authors conclude that trophoblast of the implantation site exhibits focal, mild atypia in some partial hydatidiform moles,and diffuse marked atypia in most complete hydatidiform moles. Thus, implantation site trophoblastic atypia may be a useful pathologic guideline regarding the diagnosis and classification of hydatidiform moles.

Abortion, Spontaneous↗
PubMed1996

Mosquitoes (Diptera:Culicidae) breeding in brackish water: female ovipositional preferences or larval survival?

Four species of mosquitoes were abundant in concrete reservoir tanks containing brackish water that ranged from 16 to 39% sea water. The ability of the larvae to survive in various salinities was compared for each species with the ovipositional preferences of the adult females to determine whether the 2 traits were correlated. Southern house mosquito, Culex quinquefasciatus Say, normally was not present in the tanks but survived well in salinities up to 25% sea water. However, gravid females almost always oviposited in fresh water. Culex sitiens Weidemann larvae survived best in saline water (66% sea water), but oviposition was greatest in 28% sea water; both larval survival and the frequency of oviposition were low in fresh water. Culex sinaiticus Kirkpatrick survived salinities up to 50% sea water, but the females refused to blood-feed; therefore, their ovipositional preferences were not tested. Larvae of Anopheles stephensi Liston and An. culicifacies Giles survived best in fresh water, but some An. stephensi were able to tolerate up to 50% sea water. The females had a similar ovipositional preference for fresh water. The preferred salinity for oviposition did not correspond with larval survival for Cx. quinquefasciatus and Cx. sitiens, but did compare well in An. stephensi and An. culicifacies.

Animals↗
PubMed1996

Half-dose aprotinin does not affect haemorheological properties in patients undergoing bypass surgery.

OBJECTIVE: To investigate haemorheological changes in patients undergoing coronary artery bypass grafting and to determine whether the protective effect on haemorheology of high-dose aprotinin also exists under a half-dose regimen. METHODS: Forty patients were studied in a double-blind, placebo-controlled study design. Patients in the aprotinin group received half of the standard high dose of aprotinin during surgery. Erythrocyte and white-cell clogging rates as well as whole blood and plasma viscosity were measured. Viscosity results were expressed as a ratio to the viscosity of saline. RESULTS: Erythrocyte and white-cell clogging rates were increased significantly, whereas whole blood and plasma viscosity were decreased significantly during cardiopulmonary bypass. The reduction in viscosity had a strong correlation to haemodilution. There was no significant difference in any of the measured variables between the aprotinin and the placebo groups. CONCLUSION: This study showed that blood cell damage occurred during cardiopulmonary bypass surgery, as measured by a raised clogging rate. This tendency was the same in both groups and therefore no increased potential for microthrombi could be attributed to aprotinin haemorheologically. However, half-dose aprotinin did not show any preserving effect in haemorheology when the blood-cell clogging rate and blood viscosity were studied.

Aged↗
PubMed1996

Detection and serogroup differentiation of Salmonella spp. in food within 30 hours by enrichment-immunoassay with a T6 monoclonal antibody capture enzyme-linked immunosorbent assay.

We previously described an antigen capture enzyme-linked immunosorbent assay which makes use of monoclonal antibody T6, which recognizes an epitope on the outer core polysaccharide of Salmonella lipopolysaccharide molecules that is common to almost all Salmonella serovars. In this paper, we show that this assay can detect between 10(5) and 10(7) Salmonella cells per ml even in the presence of excess Escherichia coli. A total of 153 of 154 (99%) serogroup A to E strains and 51 of 78 (71%) serogroup F to 67 strains were reactive as determined by this assay. This corresponds to a detection rate of approximately 98% of all salmonellae known to affect humans. None of the 65 strains of non-Salmonella bacteria tested positive. Taking advantage of the O-factor polysaccharides also present on the antigen captured by the immobilized T6 antibody, we showed that 136 of 154 Salmonella serogroup A to E strains (88%) were correctly differentiated according to their serogroups by use of enzyme conjugates of a panel of O-factor-specific monoclonal antibodies. We evaluated this assay for the detection and serogroup differentiation of salmonellae directly from enrichment cultures of simulated food, eggs, pork, and infant formula milk. All 26 samples which had been contaminated with Salmonella spp. were detected by T6 (100% sensitivity), with only one false-positive result from 101 samples not contaminated by Salmonella spp. (99% specificity). The detection time was substantially reduced to between 17 and 29 h, depending on the enrichment methods used. Since there were no false-negative results, we concluded that this enrichment-immunoassay method can afford rapid screening for Salmonella spp. in food samples.

Animals↗
PubMed1996

Nonvalvular myocardial involvement in metastatic carcinoid disease.

A patient with the unusual post mortem finding of myocardial metastatic carcinoid tumour without classical valvular or endocardial carcinoid disease is described. This rare occurrence may represent an aggressive type of carcinoid tumour, with metastatic disease occurring before the development of classical fibrous valvular and endocardial pathology.

Aged↗
PubMed1996

Response of ventilator-dependent patients to different levels of proportional assist.

Proportional-assist ventilation (PAV) is a form of ventilatory support in which airway pressure increases in proportion to patient effort. Because it effectively reduces the mechanical load to an adjustable extent, PAV permits the study of the pattern of breathing in patients with respiratory disease when unconstrained by abnormal respiratory mechanics. We studied 11 patients with assorted medical problems requiring ventilatory support. The patients were switched to PAV, and the level of support was varied from near-maximal levels to the lowest tolerable level. Each level was maintained for several minutes while ventilation (VE), tidal volume (VT), and respiratory rate (f) were monitored. The breathing pattern observed with the highest assist varied substantially among patients. The ranges (and means) of VE, VT, and f were 5.6-18.7 (12.8) l/min, 203-844 (517) ml, and 18-33 (25) breaths/min, respectively. The correlation between VT and VE at the highest assist was very high (r = 0.91), suggesting that ventilatory demand is the most important determinant of VT variability. There were no systematic changes in breathing pattern as the level of assist was altered; at the highest and lowest levels of support, VE, VT, and f were, respectively, 12.8 +/- 5.4 (SD) vs. 11.6 +/- 4.3 l/min, 517 +/- 217 vs. 459 +/- 175 ml, and 25.0 +/- 4.2 vs. 25.7 +/- 3.9 breaths/min. These results indicate that within each patient, in a given state, there exist unique values for a desired VE, VT, and f that are largely independent of the mechanical load; if assist is increased, patient effort is decreased to maintain the desired ventilatory targets.

Adult↗
PubMed1996

Erythropoietin does not demonstrate circadian rhythm in healthy men.

The hormone erythropoietin (Epo) produced in the kidneys in response to hypoxia stimulates the production of red blood cells. We measured serum Epo levels in 26 healthy men over a 24-h period to determine whether Epo is secreted according to a circadian rhythm. Samples were collected every 2-4 h, and Epo was measured by using a radioimmunoassay (INCSTAR Epo-trac). To determine whether blood collection had any effect on Epo production, one-half of the subjects began the collection period in the morning and the other half in the evening. Exercise and the use of prostaglandin inhibitors were prohibited to eliminate fluctuations in Epo production in response to discrete stimuli. The daily Epo concentration for all subjects combined was 15.5 +/- 5.3 (SD) U/l. No significant circadian variation in serum Epo concentrations was observed in either group or when both groups were combined; however, a measure of individual variance was observed (mean deviation = 0.8 +/- 0.4 U/l).

Adult↗
PubMed1996

Noninvasive positive-pressure ventilation in acute respiratory distress without prior chronic respiratory failure.

We evaluated the efficacy of noninvasive mechanical ventilation (NIMV) in alleviating distress and avoiding intubation in patients with de novo acute respiratory failure complicating primary medical disorders. Eleven consecutive patients with severe respiratory distress were entered. In all patients a decision to intubate on an urgent basis had been made, but NIMV could be initiated within minutes. The patients suffered from acute pulmonary edema (five), sepsis/ARDS (two), status asthmaticus (two), and severe pneumonia (two). Dyspnea score (max=10) was (+/- SD) 8.4 +.- 1.6, scale for accessory muscle use (max=5) was 4.2 +/- 0.7, and respiratory rate was 37.6 +/- 3.8 min -1. Pa CO2, pH, and base excess (BE) were 48 +/- 18 mm Hg, 7.27 +/- 0.13, and -5.5 +/- 7.4, respectively, with five patients showing severe metabolic acidosis (BE < - 10). NIMV was applied using proportional assist ventilation. There were three early failures. These included the two patients with sepsis/ARDS who did not tolerate the mask. One patient failed because Pa CO2 and pH deteriorated despite subjective improvement. The remaining eight patients demonstrated progressive improvement, and none required intubation. The duration of NIMV was 3 h to 2 d. We conclude that when NIMV is made available on a "few minutes" basis, selected patients with severe de novo respiratory distress/failure caused by reversible medical disorders, who would otherwise have been intubated, can be given substantial relief and be spared intubation.

Acid-Base Imbalance↗
PubMed1996

Factors influencing haemostasis and blood transfusion in cardiac surgery.

To find out the risk factors influencing perioperative bleeding and use of blood products in cardiac surgery so that appropriate interventions can be selected for blood conservation, risk factors were analysed in 343 cardiac surgical patients, retrospectively, by multiple regression technique. The results showed that the factors related to postoperative bleeding were male gender, Higgins score, cardiopulmonary bypass (CPB) time, operation procedures, intraoperative blood loss and use of internal mammary artery (IMA) graft. Factors related to perioperative homologous blood transfusions were emergency surgery, preoperative haemoglobin level, Higgins score, intraoperative blood loss, operation time and operation procedures. The geometric mean of postoperative bleeding in the entire series was 1085 ml and the mean packed red cell, plasma and platelet transfusions were 3.29 +/- 0.4, 1.96 +/- 0.39 and 0.21 +/- 0.05 units respectively. The incidence of homologous blood transfusion during the hospital stay was 58.9% for the entire series and 54.5% in the nonrevision patients. Emergency patients received significantly more blood transfusion (p = 0.0001). Perioperative blood loss and transfusions are still problems in cardiac surgery and certain patient groups in this study were identified as high risk; available blood conservation techniques, therefore, are recommended in these patients.

Blood Transfusion↗
PubMed1996

The provision of a palliative care service in a teaching hospital and subsequent evaluation of that service.

A survey at a large tertiary referral hospital showed that patients with cancer and HIV disease had poorly controlled symptoms. A palliative care service was introduced, employing a doctor and part-time pharmacist. The doctor was available to see and advise about terminally ill patients. With the pharmacists, an educational programme of meetings, teaching sessions and information leaflets was developed. One year after the introduction of the service a repeat survey all patients with cancer or HIV disease was carried out. Problems on admission were similar in both surveys, but fewer patients' symptom scores deteriorated during their hospital stay. There was a significantly increased use of appropriate opioid analgesics and NSAIDs. Staff were satisfied with the service.

Attitude of Health Personnel↗