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Biomedical subjects

S E Roberts

Publications and source records attributed to S E Roberts.

At least 19 recordsLinked to original sources

Coccygectomy for coccydynia: case series and review of literature.

STUDY DESIGN: This is a case series in which case notes review and telephone interview update were used to assess the outcome following coccygectomy. OBJECTIVE: To correlate the clinical results of coccygectomy with histology and discography of the sacrococcygeal and intercoccygeal segments. SUMMARY OF BACKGROUND DATA: Clinicians regard chronic disabling pain in the sacrococcygeal region with much dismay because of the reputed unpredictability of the treatment outcome. METHODS: A total of 38 patients had coccygectomy for intractable coccydynia, and 31 were available for follow-up. The excised specimen with intact sacrococcygeal joint was sent for histologic examination in 22 patients. There were 6 patients investigated using sacrococcygeal and intercoccygeal discography. RESULTS: Mean postoperative follow-up was 6.75 years (range 2-16). There were 16 patients who benefited highly from the surgery, and 6 benefited to some extent, giving an overall beneficial result of 71%. Of all specimens, 86.3% had histologic changes of degeneration. Moderate-to-severe degenerate changes in sacrococcygeal and intercoccygeal joints on histology were found in 54.5% of patients. Of these patients, 83.3% did well with surgery. Only 57.1% of those patients with mild changes did well. There were 2 patients who had positive discography, and both did well with surgery. Three patients had negative diskographies, and 2 of them had a poor result, and 1 had only some relief. CONCLUSIONS: It is possible that degenerate changes in sacrococcygeal discs and/or intercoccygeal discs are associated with pain. Surgical results are better in those with a severe degree of degenerative change. Coccygectomy remains a successful treatment for a majority of severely disabled patients with coccydynia.

Adolescent↗

Trends in mortality after hospital admission for liver cirrhosis in an English population from 1968 to 1999.

BACKGROUND: Population based mortality rates from liver cirrhosis, and alcohol consumption, have increased sharply in Britain in the past 35 years. Little is known about the long term trends over time in mortality rates after hospital admission for liver cirrhosis. AIMS: To analyse time trends in mortality in the year after admission for liver cirrhosis from 1968 to 1999. SUBJECTS: A total of 8192 people who were admitted to hospital in a defined population of Southern England. METHODS: Analysis of hospital discharge statistics linked to death certificate data. The main outcome measures were case fatality rates (CFRs) and standardised mortality ratios (SMRs). RESULTS: At 30 days after admission, CFR was 15.9% and the SMR was 93 (86 in men and 102 in women, compared with 1 in the general population). At one year, the overall CFR was 33.6% and SMR was 16.3. There was no improvement from 1968 to 1999 in mortality rates. SMRs were highest for alcoholic cirrhosis of the liver (27.4 at one year) but lower for biliary cirrhosis (11.4) and chronic hepatitis (10.0). Mortality from most of the main causes of death, including accidents and suicides, was increased. CONCLUSIONS: The high mortality rates after hospital admission, and the fact that they have not fallen in the past 30 years, show that liver cirrhosis remains a disease with a very poor prognosis. Increased mortality from accidents, suicides, and mental disorders, particularly among those with alcoholic cirrhoses, indicates that prognosis is influenced by behavioural as well as by physical pathology.

Adult↗

Trends in mortality and hospital admission rates for abdominal aortic aneurysm in England and Wales, 1979-1999.

BACKGROUND: The aim of this study was to investigate trends in population-based mortality, hospital admission and case fatality rates for abdominal aortic aneurysm (AAA) from 1979 to 1999. METHODS: This was an analysis of routine statistics from 79 495 death certificates in England and Wales and 3217 hospital inpatient admissions in the Oxford Region. RESULTS: Mortality rates for all AAAs increased between 1979 and 1999 from 13 to 25 per million in women and from 80 to 115 per million in men. Admission rates increased in the same time interval from three to 22 admissions per million per year in women, and from 52 to 149 per million per year in men. Case fatality rates for all non-ruptured AAAs that were operated on decreased from 25.8 to 9.0 per cent and for all ruptured AAAs from 69.9 to 54.4 per cent. CONCLUSION: Mortality rates and hospital admission rates for AAA rose in men and even more so in women between 1979 and 1999. Perioperative mortality for ruptured AAA declined a little during the study but nonetheless was still very high at the end. This reinforces the importance of detecting and treating AAA before rupture occurs.

Aortic Aneurysm, Abdominal↗

The effect of low-dose ritonavir monotherapy on fasting serum lipid concentrations.

OBJECTIVES: Ritonavir (RTV) at doses of 400 mg twice a day (bid) or higher adversely affects serum lipids. However, the effect of RTV 100 mg bid on serum lipids is unknown. We conducted a study to evaluate the effect of RTV 100 mg bid on fasting serum lipid profiles in HIV-negative healthy volunteers. METHODS: Ritonavir 100 mg bid was administered for 14 days to 20 healthy HIV-seronegative adults with normal serum lipids. After a 7-day washout, lopinavir/ritonavir (LPV/RTV) 400/100 mg bid was administered for 14 days. Fasting serum lipid parameters were measured twice at baseline, after 14 days of RTV, and after 14 days of LPV/RTV, and comparisons were made at each time-point for levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, the total/HDL cholesterol ratio and triglycerides. RESULTS: After 14 days of RTV 100 mg bid, total cholesterol level increased by 10.2% (P<0.001), LDL cholesterol level increased by 16.2% (P<0.001), triglyceride levels increased by 26.5% (P<0.001), HDL cholesterol level decreased by 5.4% (P<0.01) and the total/HDL cholesterol ratio increased by 17.3% (P<0.001). The addition of LPV 400 mg bid to RTV 100 mg bid resulted in no significant further changes in LDL cholesterol or triglyceride level or total/HDL cholesterol ratio, but there were significant increases in both total cholesterol (8.0% increase; P=0.007) and HDL cholesterol levels (6.7% increase; P=0.008). CONCLUSIONS: Ritonavir dosed at 100 mg bid significantly increased the concentration of total cholesterol, LDL cholesterol, total/HDL cholesterol ratio and triglycerides and reduced HDL cholesterol concentration. The addition of LPV 400 mg bid to RTV 100 mg bid further increased both total and HDL cholesterol levels without affecting the total/HDL ratio.

Adolescent↗

Traumatic work related mortality among seafarers employed in British merchant shipping, 1976-2002.

AIMS: To establish the causes and circumstances of all traumatic work related deaths among seafarers who were employed in British merchant shipping from 1976 to 2002, and to assess whether seafaring is still a hazardous occupation as well as a high risk occupation for suicide. METHODS: A longitudinal study of occupational mortality, based on official mortality files, with a population of 1,136,427 seafarer-years at risk. RESULTS: Of 835 traumatic work related deaths, 564 were caused by accidents, 55 by suicide, 17 by homicide, and 14 by drug or alcohol poisoning. The circumstances in which the other 185 deaths occurred, including 178 seafarers who disappeared at sea or were found drowned, were undetermined. The mortality rate for 530 fatal accidents that occurred at the workplace from 1976 to 2002, 46.6 per 100,000 seafarer-years, was 27.8 times higher than in the general workforce in Great Britain during the same time period. The fatal accident rate declined sharply since the 1970s, but the relative risk of a fatal accident was 16.0 in 1996-2002. There was no reduction in the suicide rate, which was comparable to that in most high risk occupations in Britain, from 1976 to 1995; but a decline since 1995. CONCLUSIONS: Although there was a large decline in the fatal accident rate in British shipping, compared to the general workforce, seafaring has remained a hazardous occupation. Further prevention should focus on improvements in safety awareness among seafarers and shipping companies, reductions in hazardous working practices, and improvements in care for seafarers at risk of suicide.

Accidents, Occupational↗

Occupational mortality in British commercial fishing, 1976-95.

AIMS: To establish the causes and circumstances of all deaths occurring at work or related to work among fishermen in British commercial fishing between 1976 and 1995. METHODS: A retrospective study, based on official mortality files, with a population of 440 355 fishermen-years at risk. RESULTS: Of 616 deaths in British fishing, 454 (74%) were due to accidents at work, and 394 (87%) of these fishermen drowned. A total of 270 accidents were caused by casualties to vessels and 184 by personal accidents. There was no significant decline in the fatal accident rate, 103.1 per 100 000 fishermen-years, between 1976 and 1995. The fatal accident rate was 52.4 times higher (95% CI 42.9 to 63.8) than for all workers in Great Britain during the same period, and this relative risk increased through the 1980s up to 76.6 during 1991-95. Relative risks with the construction (12.3) and manufacturing (46.0) industries were higher than 5 and 20 respectively, during 1959-68. Trawlers foundering in adverse weather was the most frequent cause of mortality from casualties to vessels (115 deaths), and 82 of 145 personal accidents at sea arose during operations involving trawling nets. CONCLUSIONS: When compared with shore based industries, fishing remains at least as hazardous as before. Prevention should be aimed, most importantly, at the unnecessary operation of small vessels and trawling net manoeuvres in hazardous weather and sea conditions. Other measures should focus on preventing falls overboard, reducing fatigue, a more widespread use of personal flotation devices, and improvements in weather forecast evaluation.

Accidents, Occupational↗

Molecular and fluorescence in situ hybridization characterization of the breakpoints in 46 large supernumerary marker 15 chromosomes reveals an unexpected level of complexity.

Supernumerary marker chromosomes (SMCs) of chromosome 15, designated "SMC(15)s," are the most common SMC in humans, accounting for as much as 60% of all those observed. We report the characterization of 46 large SMC(15)s, using both fluorescence in situ hybridization and polymerase chain reaction analysis within and distal to the Prader-Willi/Angelman syndrome critical region (PWACR). Our aim was to establish detailed information on origin, content, and breakpoints, to address the formation of SMC(15)s, and to facilitate genotype-phenotype correlations. For all patients in whom we were able to establish the parental origin, the SMC(15)s were maternally derived. Two patients were observed who had familial SMC(15)s, both inherited from the mother; however, in all remaining patients for whom parental samples were available, the SMC(15)s were shown to have arisen de novo. With one exception, all the SMC(15)s were shown to include the entire PWACR. Detailed investigations of the distal breakpoints categorized the SMC(15)s into two groups. Group A, representing approximately two-thirds of the SMC(15)s, had a breakpoint beyond the standard distal PWS/AS deletion breakpoint BP3, at a position close to the microsatellite marker D15S1010 and the bacterial artificial chromosome 10I10. The group B SMC(15)s were shorter, with more variable breakpoints located around BP3. The majority of the SMC(15)s were shown to have asymmetrical breakpoints, with the two inverted arms of the SMC being unequal in length. Our study revealed an unexpected level of complexity and heterogeneity among SMC(15)s that is not seen in other chromosome 15 rearrangements, such as deletions and duplications. This suggests that multiple mechanisms are involved in the formation of large SMC(15)s.

Alleles↗

Immunoglobulin-binding domains: Protein L from Peptostreptococcus magnus.

Protein L is a multidomain cell-wall protein isolated from Peptostreptococcus magnus. It belongs to a group of proteins that contain repeated domains that are able to bind to Igs without stimulating an immune response, the most characterized of this group being Protein A ( Staphylococcus aureus ) and Protein G ( Streptococcus ). Both of these proteins bind predominantly to the interface of C(H)2-C(H)3 heavy chains, while Protein L binds exclusively to the V(L) domain of the kappa -chain. The function of these proteins in vivo is not clear but it is thought that they enable the bacteria to evade the host's immune system. Two binding sites for kappa -chain on a single Ig-binding domain from Protein L have recently been reported and we give evidence that one site has a 25-55-fold higher affinity for kappa -chain than the second site.

Amino Acid Sequence↗

Long-term SO2 dispersion modeling over a coastal region.

Air dispersion modeling over coastal regions has proven to be a remarkable challenge in the field of air quality. Many conventional plume dispersion models, such as ISC2 and HYSPLIT, are unable to model such dispersion with the precision that is necessary to accurately predict ground-level concentrations in coastal areas. Considering this, the present work was carried out with two primary objectives: i) to evaluate the effectiveness of currently available mathematical models in predicting plume dispersion over a coastal region and ii) to study the impact of sulfur dioxide emissions from a petroleum refinery over a different community located in the adjacent area. This study demonstrates that CALPUFF predictions are more reliable compared to those of the other models studied, however the operation of CALPUFF is highly data intensive and in many instances, it is difficult to obtain all required input data. This is a particular problem for regions outside ofthe United States of America where sufficient data is difficult to obtain. In addition, the study concluded that the predicted annual average SO2 concentrations in the nearby communities are well within regulatory limits.

Air Movements↗

An analysis of the causes of mortality among seafarers in the British merchant fleet (1986-1995) and recommendations for their reduction.

This study was designed to establish the manner and causes of all fatalities among seafarers who were serving in British merchant shipping between 1 January 1986 and 31 December 1995. Other main aims were to compare mortality rates with workers in other industries and with seafarers in other merchant fleets, and to discuss recommendations for the prevention of occupational mortality. This study was based upon official mortality files with a population of 253 919 seafarer-years at risk. There was a total of 252 fatalities in British merchant shipping during the study period. One hundred and seven of the 252 deaths were due to natural causes, of which 93 (87%) were caused by cardiovascular disease. The relative risk of mortality due to accidents at work (96 fatalities) was 23.9 times higher than for all workers in Great Britain during the same time period (95% confidence interval = 14.0-40.7). The risk of a fatal accident in merchant shipping was also much higher than in other British industrial sectors, such as agriculture, forestry and fishing (relative risk = 4.5), construction (5.5), and manufacturing (22.0). Seafaring was identified as a dangerous occupation compared with shore-based employment. Many of the fatal accidents at work were caused by hazardous working practices and were often preventable, as were the many off-duty accidents and drowning that were caused by seafarers falling into docks when encountering hazardous access to their ships from the shore. Seafarers are also at special risk from acute illnesses since they lack direct access to specialist medical care.

Accidents, Occupational↗

Studies on the synthesis of landomycin A: synthesis and glycosidation reactions of L-rhodinosyl acetate derivatives.

An efficient, eight-step synthesis of L-rhodinosyl acetate derivative 3 is described. The synthesis originates from methyl (S)-lactate and involves a highly stereoselective, chelate-controlled addition of allyltributylstannane to the lactaldehyde derivative 7. The beta-anomeric configuration of 3 was established with high selectivity by acetylation of the pyranose precursor with Ac(2)O and Et(3)N in CH(2)Cl(2). Preliminary studies of glycosidation reactions of 3 and L-rhodinosyl acetate 10 containing a 3-O-TES ether revealed that these compounds are highly reactive glycosidating agents and that trialkylsilyl triflates are effective glycosylation promoters. The best conditions for reactions with 15 as the acceptor involved use of diethyl ether as the reaction solvent and 0.2 equiv of TES-OTf at -78 degrees C. However, the TES ether protecting group of 10 proved to be too labile under these reaction conditions, and mixtures of 16a, 17, and 18a are obtained in reactions of 10 and 15. Disaccharide 17 arises via in situ cleavage of the TES ether of disaccharide 16a, while trisaccharide 18a results from a glycosidation of in situ generated 17 (or of 16a itself) with a second equivalent of 10. These problems were largely suppressed by using 3 with a 3-O-TBS ether protecting group as the glycosyl donor and 0.2 equiv of TES-OTf as the reaction promoter. Attempts to selectively glycosylate the C(3)-OH of diol acceptors 20 or 28 gave a 70:30 mixture of 21 and 22 in the reaction of 20 and a 43:27:30 mixture of regioisomeric trisaccharides 29 and 30 and tetrasaccharide 31 from the glycosidation reaction of 28. However, excellent results were obtained in the glycosidation of differentially protected disaccharide 34 using 1.5 equiv of 3 and 0.05 equiv of TBS-OTf in CH(2)Cl(2) at -78 degrees C. The latter step is an important transformation in the recently reported synthesis of the landomycin A hexasaccharide unit.

Aminoglycosides↗

Why people with probable minor psychiatric morbidity consult a doctor.

This epidemiological investigation examines factors determining medical consultation in people with probable minor psychiatric morbidity. About 54% of people with probable minor psychiatric morbidity and about 23% of the (numerically much greater) remainder with lower probability of psychiatric morbidity consulted a doctor, usually a primary care physician, in the two weeks prior to a research interview. Medical consultation rates were higher in females than in males. The dominant finding was that in people with probable minor psychiatric morbidity physical illness was strongly associated with medical consultation. Almost 89% of males and 97% of females with probable minor psychiatric morbidity and physical illness consulted a doctor in the two weeks prior to interview. Logistic regression modelling was used to investigate the joint effects on medical consultation of physical illness and six socio-demographic variables, and physical illness emerged as the major single determinant of medical consultation in women and, in men, it exerted its effect through an interaction with lower educational level.

Adolescent↗

A comparison of delmopinol and chlorhexidine on plaque regrowth over a 4-day period and salivary bacterial counts.

Delmopinol has been considered as a potential agent for the chemical control of plaque. The aims of these studies were to measure the effects of a 0.2% delmopinol hydrochloride mouthrinse on (1) plaque reformation and (2) salivary bacterial counts. Comparisons were made with a 0.2% chlorhexidine rinse and a placebo rinse. A group of 12 male volunteers took part in the plaque study which was of a double blind, randomised, 3 cell, cross-over design. From a zero plaque baseline subjects rinsed, 2x a day, under supervision, for 1 min with 10-ml volumes of the allocated rinse. After 4 days, during which no other form of oral hygiene was performed, plaque was scored by area and index. Plaque results were significantly lower with chlorhexidine and delmopinol compared with control, and with chlorhexidine compared to delmopinol. Side-effects with delmopinol were transient tingling and numbness of the tongue in some subjects. A 2nd group of 12 male volunteers received single, 1-min rinses of the 3 formulations. Salivary bacterial counts were determined immediately before and up to 420 min after rinsing. Compared to the control rinse, chlorhexidine significantly reduced bacterial counts of 420 min. Delmopinol produced a small reduction in bacterial counts which was only significantly different from control at one time point. Delmopinol deserves further evaluation as a chemical plaque inhibitor, particularly when used as an adjunct to normal toothcleaning.

Adult↗

Evaluation of a replenishment type oxygen consumption monitor.

This paper describes the testing of a monitor (Oxyconsumeter) which uses a replenishment technique to measure oxygen consumption (VO2). Oxygen is added to the expired gas to replace the oxygen consumed by the patient. The replenishing oxygen flow equals the patients's VO2 when the mixed replenished expired oxygen fraction equals the inspired oxygen fraction. The accuracy of the Oxyconsumeter was assessed using a N2 and CO2 dilution technique. When tested over the operating range specified by the manufacturer, the bias of the Oxyconsumeter was 1.66% of reading. The reproducibility averaged 6.96% of reading. The reproducibility did not change with VO2, FIO2 or minute ventilation. The replenishment technique has the theoretical advantage that an absolute oxygen sensor calibration is not necessary and a respiratory flowmeter is not needed. It appears, from the laboratory testing, that the Oxyconsumeter has sufficient accuracy for use in the critical care setting.

Equipment Design↗

Determination of chlordiazepoxide, its hydrochloride and related impurities in pharmaceutical formulations by reversed-phase high-performance liquid chromatography.

A quantitative high-performance liquid chromatographic method using an octadecylsilane column and a methanol-water mobile phase was employed for the determination of chlordiazepoxide, chlordiazepoxide X HCl and related impurities in capsule and tablet preparations. Each component is well separated and directly detected by 254 nm absorption. For chlordiazepoxide and chlordiazepoxide X HCl the coefficient of variation for replicated injections was below 1%. Recovery of authentic samples ranged from 98.4 to 101.6% for both capsule and tablet formulations.

Capsules↗