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Biomedical subjects

R Scott

Publications and source records attributed to R Scott.

At least 235 records · Page 13Linked to original sources
PubMed1988

The compartment syndrome. An experimental and clinical study of muscular energy metabolism using phosphorus nuclear magnetic resonance spectroscopy.

In an experimental ischemic compartment syndrome in dogs, phosphorus (31P) nuclear magnetic resonance (NMR) spectroscopy was used to determine the tissue pressure threshold at which resting skeletal muscle begins to use anaerobic energy sources due to insufficient cellular oxygen delivery. The interactive effects of systemic perfusion pressure and moderate muscle trauma on this anaerobic threshold were also evaluated. The severity of cell injury produced by various degrees of compartment pressurization over an eight-hour period was concomitantly studied using muscle biopsy and electron microscopy. Clinical correlation of a preliminary patient series studied using 31P-NMR demonstrated that the threshold for cellular metabolic derangement in skeletal muscle subjected to increased tissue pressure was more closely associated with the difference between mean arterial blood pressure (MABP) and compartment pressure than with the absolute compartment pressure alone. The difference is termed MABP-compartment pressure, or delta P. The lowest delta P at which a normal cellular metabolic state can be maintained is approximately 30 mmHg in normal muscle and 40 mmHg in moderately traumatized muscle. It is imperative to interpret compartment pressure measurements in light of the degree of soft tissue trauma sustained and the patient's blood pressure, as well as the clinical signs and symptoms.

Animals↗
PubMed1987

The mitochondrial genotype can influence nuclear gene expression in yeast.

Isochromosomal, respiratory-deficient yeast strains, such as a mit-, a hypersuppressive petite, and a petite lacking mitochondrial DNA, are phenotypically identical in spite of differences in their mitochondrial genomes. Subtractive hybridizations of complementary DNA's to polyadenylated RNA isolated from derepressed cultures of these strains reveal the presence of nuclear-encoded transcripts whose abundance varies not only between them and their respiratory-competent parent, but among the respiratory-deficient strains themselves. Transcripts of some nuclear-encoded mitochondrial proteins, like cytochrome c and the alpha and beta subunits of the mitochondrial adenosine triphosphatase, whose abundance is affected by glucose or heme, do not vary. In the absence of major metabolic variables, yeast cells seem to respond to the quality and quantity of mitochondrial DNA and modulate the levels of nuclear-encoded RNA's, perhaps as a means of intergenomic regulation.

Base Sequence↗
PubMed1987

Species differences in the behavioral toxicity produced by intrathecal substance P antagonists: relationship to analgesia.

Intrathecal administration of [D-Pro2,D-Trp7,9]-substance P to rats produced an irreversible flaccid paralysis of the hind limbs (paraplegia) which was irreversible with an ED50 of 2.3 micrograms. At 5 micrograms intrathecally, [D-Pro2,D-Phe7,D-Trp9]-substance P, [D-Trp7,9]-substance P and [D-Pro4,D-Trp7,9,10]-substance P octapeptide also produced paraplegia (70-80%). Surprisingly, intrathecal administration of up to 20 micrograms of these analogs to the mouse produced no paraparesis or paraplegia. In the guinea pig or rabbit, 20 micrograms of [D-Pro2,D-Trp7,9]-substance P or [D-Pro4,D-Trp7,9,10]-substance P octapeptide were also devoid of paraparetic effects. Lidocaine hydrochloride, on the other hand, was equieffective across species in producing paraplegia (which was reversible) suggesting that interspecies susceptibility is not a factor in the marked species differences between substance P analogs. In the mouse, intrathecal [D-Pro2,D-Trp7,9]-substance P was active in tail-flick and hot-plate tests at doses showing no overt behavioral effects but in the rat was not analgesic at sub-paraplegic doses. Lidocaine hydrochloride (i.t.) was analgesic in mouse and rat tail-flick tests at doses two times less than paraplegic doses; however, there was an overlap in analgesic and paraplegic doses. Based on these data, we suggest that the rat is unique in being extremely sensitive to the paraplegic effects of intrathecal neurokinin antagonists and may simply be a poor species in which to study the spinal functionality of neurokinins.

Analgesia↗
PubMed1987

Mammary immunity in mothers of infants with respiratory syncytial virus infection.

Seven of 230 breast fed infants followed prospectively from birth through their first winter contracted RS virus infections. The colostral from five of the mothers of these infants contained antiviral IgA antibodies. In each case antibody levels were above the mean for a group of 36 mothers whose infants were age matched to infected infants but for whom there was no evidence of RS virus infection in their first winter. Four colostral samples from mothers of infected infants also contained antiviral IgG antibody. Colostral lymphocyte reactivity to RS virus antigen was tested in three mothers of infected infants and two showed significant proliferation. There was, therefore, no evidence that mothers of infected infants lacked mammary immunity to the virus. Maternal mammary IgA and IgG responses following diagnosis of RS virus infection in the infant were followed for the seven cases identified prospectively and for a further 23 infants admitted to hospital with RS virus infections of varying severity. There was no evidence that the mothers of more severely affected infants were deficient in IgA or IgG milk antibody.

Animals↗
PubMed1987

The in vitro assessment of a collagen/vicryl (polyglactin) composite film together with candidate suture materials for use in urinary tract surgery. I. Physical testing.

A Vicryl (Polyglactin)/Collagen composite membrane has been developed for potential use in urinary tract surgery. The compatability of this membrane, together with its two individual components, collagen film and vicryl mesh, has been tested over a three week period in urine obtained from both healthy and from stone forming patients. The rate of degradation as indicated by changes in the mechanical strength was determined at regular intervals. In addition, absorbable suture materials such as plain catgut, chromic catgut, and vicryl were similarly tested; in the latter case, the breaking stress, and actual loss of weight of the material were compared. The whole series of experiments were then repeated in urine obtained from rabbits, the animal chosen for any future in vivo studies.

Animals↗
PubMed1987

An assessment of a collagen/vicryl composite membrane to repair defects of the urinary bladder in rabbits.

Collagen/vicryl (Polyglactin) composite membrane has been used to repair full-thickness defects in the urinary bladder of rabbits. The material has been shown to be biodegradable, prevent leakage of urine, and is readily replaced by collagenous scar tissue lined with a urothelium. Regeneration of smooth muscle has been observed in the repair area of some animals. The results suggest that such a material may well be of use to urologists wishing to augment contracted bladders or in the repair of bladder fistulae in human subjects, thereby avoiding the use of bowel or other material e.g. omentum.

Animals↗
PubMed1987

The use of a biodegradable collagen/vicryl composite membrane to repair partial nephrectomy in rabbits.

A composite membrane produced from collagen and vicryl mesh has been used to cover the kidney surface following partial nephrectomy in rabbits. The membrane readily held sutures, gave satisfactory haemostasis, and prevented leakage of urine. The experiments showed that the prosthesis biodegraded in less than twenty weeks. The only observed long-term effect of the material was thickening of the renal capsule. The results indicate that this membrane may be a suitable reparative material for use in traumatised kidneys in humans.

Animals↗
PubMed1987

Particulate allogeneic bone grafts into maxillary alveolar clefts in humans: a preliminary report.

The purpose of this study was to determine the ability of particulate allogeneic bone graft to adequately bridge unilateral maxillary alveolar clefts in humans. Twenty patients with unilateral alveolar clefts and oronasal fistula underwent alveolar cleft grafting with a clinically appropriate amount of particulate allogeneic bone. The grafted cleft area was followed radiographically for three to six months postsurgery. Although it was difficult to quantitate, it was both clinically and radiographically apparent at three months that bone bridging and filling of the cleft had occurred in 100% of the cases. From this study, it appears that allogeneic bone is a viable alternative for repairing alveolar clefts and that its use has a significant benefit to the patient by eliminating the morbidity of a second operative site.

Adolescent↗
PubMed1987

Prevalence and patterns of spina bifida occulta in 2707 normal adults.

Plain radiographs of the urinary tract on 2707 normal volunteers were reviewed to establish the prevalence and patterns of spina bifida occulta in the normal population. Abnormalities in the formation of the posterior arch were identified in 23%, and four different patterns are described. In this group of subjects the condition was twice as common in males as in females (P less than 0.001) and commoner in younger adults. The commonest defects were either in S1 alone or involved S1 and S2 together. Isolated defects at L5 or S2 were rare. The level of opening of the posterior sacral arcs was assessed and a high level of opening was shown to correlate with the presence of spina bifida occulta.

Adult↗
PubMed1987

Determination of volatile priority pollutants in water by purge and trap and capillary column gas chromatography/mass spectrometry.

Two wide-bore capillary columns are evaluated for their applicability to the purge-and-trap technique and GC/MS analysis of 34 volatile organics. Neither column is able to completely resolve all 34 compounds, as is also typical of the packed column; however, the analysis is faster than with the packed column (18 to 21 min compared to 30 min), and the column effluent is introduced directly into the mass spectrometer without requiring an open-split interface. Method precision, as assessed from the instrument response at a concentration of 50 micrograms/L per component, is better than +/- 5% for 41% of the compounds using the VOCOL column (diphenyl dimethyl polysiloxane with crosslinking moieties) and for 53% of the compounds using the 007 column (95% methyl 5% phenyl silicone). The instrument response is linear from 20 to 200 micrograms/L for most compounds, and the amounts loaded to either column without serious distortion of the peak shape or resolution can be as high as 5 micrograms per component. Because the VOCOL column resolved more compounds than the 007 column within approximately the same analysis time, this column is further tested for performance with groundwater samples.

Gas Chromatography-Mass Spectrometry↗
PubMed1987

Strain variation of respiratory syncytial virus.

Western blotting and immunoperoxidase staining with monoclonal antibodies were employed to analyse epitopic and polypeptide molecular weight variation among isolates of respiratory syncytial (RS) virus collected in Newcastle between 1965 and 1986. One group of isolates resembled the A2 and Long prototype subgroup A strains of RS virus in possessing a P protein of Mr 34,000. Isolates in this subgroup showed two patterns of reactivity with subgroup A-specific monoclonal antibodies to the G glycoprotein and 22K protein. Isolates with both reactivity patterns were isolated throughout the period studied. Isolates in the second group resembled the 8/60 subgroup B prototype strain in their lack of reactivity to subgroup A-specific monoclonal antibodies but were heterogeneous in P protein molecular weight. The earliest isolate only, made in 1965, possessed a P protein of Mr 31,000 resembling the prototype strain. All subsequent subgroup B isolates possessed a higher Mr, 33,000, P protein. Overall, subgroup A viruses were isolated most frequently although subgroup B strains may have predominated in some epidemics.

Antibodies, Monoclonal↗
PubMed1987

Heterogeneity of the respiratory syncytial virus 22K protein revealed by Western blotting with monoclonal antibodies.

Respiratory syncytial (RS) virus-infected HeLa, HEp-2, Vero and BS-C-1 cell lysates were electrophoresed on SDS-polyacrylamide gels under reducing conditions and analysed by Western blotting and immunoperoxidase using monoclonal antibodies specific for the 22K protein (relative mol. wt. of 23,000 in our gel system). Three novel polypeptides with mol. wt. of 24,000, 21,000 and 17,000 were stained in addition to the 23,000 polypeptide which was present in the greatest amount in all three virus strains tested regardless of host cell line. When samples were electrophoresed under non-reducing conditions each of the three higher mol. wt. polypeptides seen in reducing gels migrated as two bands (total of six bands) with altered electrophoretic mobilities. In experiments using the alkylating agent iodoacetamide under conditions where the novel 24,000, 21,000 and 17,000 polypeptides were not visible, the number of mobility variants of the 23,000 polypeptide which could be detected in non-reducing conditions was increased from two to four. At least one, and possibly three, of these variants was the result of conformational variation in the 23,000 polypeptide caused by the generation or rearrangement of intrachain disulphide bonds after the infected cells were lysed in SDS-PAGE sample buffer. Post-lysis conformational changes were minimized by treatment of the infected cells with iodoacetamide before solubilization or by decreasing the SDS concentration or using milder detergents in the lysis buffer.

Antibodies, Monoclonal↗
PubMed1987

Expression of the respiratory syncytial virus 22K protein on the surface of infected HeLa cells.

Immunofluorescent staining of unfixed respiratory syncytial virus-infected HeLa cells with monoclonal antibodies (MAbs) demonstrated that the 22K protein is expressed on the cell membrane along with the fusion (F) protein and large glycoprotein (G). All three proteins were detected in the cytoplasm at 17 h post-infection and in the case of the F and G proteins this coincided with their appearance on the cell surface. However, the 22K protein could not be detected on the surface until approximately 16 h after its detection in the cytoplasm, when cytopathic effect was extensive. No evidence for the surface expression of the phosphoprotein (P), matrix (M) or nucleocapsid (N) proteins was found. Trypsin treatment of infected cells prior to unfixed immunofluorescent staining and Western blot analysis indicated that, unlike the G protein, the quantity of 22K protein detected on the cell surface constituted only a small proportion of the total present in the cell. A comparison of the patterns of immunofluorescent staining produced by MAbs on acetone-fixed infected cells suggested that the N, P and 22K proteins, but not the M protein, may be associated with the same intracellular structures.

Capsid↗
PubMed1987

Prevalence of calcified upper urinary tract stone disease in a random population survey. Report of a combined study of general practitioners and hospital staff.

There are few randomised studies specifically designed to establish the prevalence of upper urinary tract stone disease. The present random study sampled a population of 7000 in the central belt of Scotland. Three thousand three hundred and ninety-eight subjects were X-rayed and possible calcified upper tract stones were further investigated, revealing a prevalence rate of 3.5% of the total surveyed population. Socio-economic characteristics of the population were determined, such as occupation, history of previous infection, stone disease and backache. Simple urine and blood analyses were undertaken. There was no difference in stone prevalence between males and females (1.03:1) as distinct from treated stone patients. There were no differences between the sexes with respect to family history of stone disease but females have a greater chance of having had previous urinary tract infection.

Adolescent↗
PubMed1987

Cadmium concentrations in human kidneys from the UK.

The concentration of cadmium in the cortex and medulla of nearly 1000 kidneys obtained at autopsy was determined by atomic absorption spectrophotometry. Particular care was taken over the analytical procedures to ensure the accuracy and precision of the results; intrakidney variability was examined and found to be small. The frequency distributions of cadmium concentrations were approximately lognormal. There was much variability in cadmium concentrations between individuals, with geometric coefficients of variation for both cortex and medulla of around 100%. Cadmium concentrations varied with age and smoking habits, but not sex. Values were successively higher than those in the previous age-group up to 50-59 years (geometric mean 19 micrograms/g), after which they were successively lower; on average, heavy smokers had cadmium concentrations some 15-20% higher than those in light smokers who in turn had values some 15-20% higher than those in non-smokers. No definite conclusions could be reached on the variation of cadmium concentrations with either cause of death or location, or over time. The present study, the first of its kind in the UK, has provided benchmark data; its results are broadly in line with those from previous but smaller studies in other countries.

Adult↗
PubMed1987

Supracondylar fracture of the femur after total knee arthroplasty.

In a review of 250 total knee arthroplasties, five patients with rheumatoid arthritis incurred supracondylar fractures of the femur. These fractures may be associated with a surgical encroachment of the anterior femoral cortex during resection of the patellar trochlea. Forty-two percent of patients with excessively deep resections of the patellar trochlea suffered fractures. No fractures occurred in patients without encroachment of the anterior femoral cortex. All patients with fractures also had significant osteoporosis, which may have predisposed them to fracture. A resection of the patellar trochlea that is made too deeply would interrupt the transmission of stresses through the cancellous bony trabeculae of the anterior femoral cortex and could predispose to fracture.

Aged↗