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Biomedical subjects

R J Scott

Publications and source records attributed to R J Scott.

141 records · Page 8Linked to original sources
PubMed1974

A comparative study of viruses associated with acute haemorrhagic conjunctivitis.

Seven representative isolates from six outbreaks of acute haemorrhagic conjunctivitis were shown to have the characteristics of enteroviruses. Two viruses differed from the remaining five isolates in producing paralysis in suckling mice and being resistant to 2-hydroxybenzyl-benzimidazole. These two viruses were also closely related antigenically and distinct from the other five viruses which were serologically similar to each other. Neither group of viruses was inhibited by antisera to the known enteroviruses and they probably represent two new enterovirus types one related to the Coxsackie A viruses and the other to the echoviruses.

Acute Disease↗
PubMed1973

The isolation of enteroviruses from cases of acute conjunctivitis.

In two epidemics of acute enterovirus conjunctivitis the diagnosis could only be established by the use of human embryonic organ cultures. In one instance cultures of ciliated respiratory epithelium proved sensitive to the virus but similar culture failed to support growth of the virus from the second outbreak which was isolated in organ cultures of conjunctiva. The virus associated with a third outbreak had previously been isolated from the original material by culture in human embryo kidney cells, but it required passage in organ culture for its detection after the specimens had been diluted.

Animals↗
PubMedDate not supplied

Hypoplastic left heart syndrome in the second trimester.

Hypoplastic left heart syndrome is a relatively common congenital anomaly with a high mortality even after palliative postnatal surgery. The case presented had a normal cardiac cavity and great artery dimensions at 19 weeks of gestation but bright left ventricular myocardial echoes, impaired left ventricular shortening, and no detectable forward flow in the left ventricular outflow tract. Autopsy showed left ventricular subendocardial calcification. This demonstrates a likely early stage in the evolution of hypoplastic left heart syndrome, which has a variable time course. The abnormal left ventricular myocardial performance associated with low left ventricular output results in a failure of growth of the left heart rather than there being a primary failure of embryogenesis.

Female↗
PubMedDate not supplied

Acute osteomyelitis in children: a review of 116 cases.

We reviewed 116 cases of acute hematogenous osteomyelitis (AHO) (without septic joints) from 1979 to 1985 to establish current patterns of clinical presentation, modes of treatment, and success of therapy. We found that patients present early in the course of their disease, and many have no findings other than local tenderness and an elevated sedimentation rate. Sixty-four of the patients were treated nonoperatively. The average antibiotic treatment time was 2 weeks by intravenous (i.v.) administration followed by additional outpatient oral therapy for periods of up to 4 weeks. This treatment regimen applied specifically to acute osteomyelitis led to no known treatment failures.

Adolescent↗
PubMedDate not supplied

Effects of impermeant medium ions on the composition of rabbit renal cortical slices.

When incubated in isosmotic oxygenated medium in which chloride was completely replaced by gluconate, rabbit renal cortical slices lost chloride with sodium, potassium and water before reaching a new steady-state composition after 15-30 min. When corrected for extracellular space, there was an electroneutral loss of alkali metal cations (Na + K) with chloride, accompanied by isosmotic loss of water from the cells. The losses of chloride and water were independent of medium pH over the range of 6.4-8.2, and were the same with potassium rather than sodium as the dominant medium cation. Incubation in isosmotic sodium chloride medium restored tissue composition of slices transferred from gluconate medium. This recovery was not dependent specifically upon medium chloride, for slice water content also recovered when nitrate rather than chloride was substituted for medium gluconate. With sodium completely replaced by n-methyl d-glucamine (nmdG+), cells in slices lost far more sodium and potassium than chloride before reaching a new steady-state composition after some 30 min. However, the loss of water was as predicted from the total losses of measured inorganic ions. With sodium and chloride completely replaced by nmdG+ and gluconate, there was a greater loss of water than found with unilateral substitutions. Again, the combined loss of diffusible inorganic cations exceeded the loss of chloride but the water loss was that expected for isosmotic loss accompanying the measured losses of ions. These results reveal that both gluconate and nmdG+ behave as impermeant ions in this tissue preparation. It is suggested that, in the absence of medium sodium, sodium-hydrogen exchange is inhibited. Retained hydrogen ions are buffered on charged cellular non-diffusible solutes and the associated hydroxyl (or bicarbonate) ions are lost from the cells accompanied by the inorganic univalent cations lost in excess of chloride in nmdG+ medium.

Animals↗
PubMedDate not supplied

Whole body hyperthermia in dogs using a radiant heating device: effect of surface cooling on temperature uniformity.

Rectal and subcutaneous temperatures were measured during a total of 10 whole body hyperthermia treatments conducted in six dogs. During five of the treatments skin cooling, by means of initiating air flow through the radiant heating device, was necessary during the plateau phase because rectal temperature exceeded the target value. Skin cooling was not necessary in the other five treatments. Although the rectal temperatures were similar in all 10 treatments, extensive and rapid subcutaneous temperature non-uniformity, of approximately 4 degrees C, developed during treatments where skin cooling was necessary. During the treatments where skin cooling was not necessary, the subcutaneous temperature remained approximately equal to the rectal temperature. These data indicate that the environment in the radiant heating device during the plateau phase can have a profound effect on the temperature at superficial sites, which is not reflected by the temperature measured at deeper sites. The temperature at superficial sites should be measured during whole body hyperthermia to assure that the prescribed heat dose is administered to the largest percentage of body mass possible. Active skin cooling during whole body hyperthermia should be avoided if possible.

Animals↗
PubMedDate not supplied

Whole-body hyperthermia combined with hyperfractionated irradiation of the thorax in dog: acute physiological response.

Whole-body hyperthermia has potential as an adjuvant treatment with chemotherapy and radiation therapy for diseases such as lung cancer which require both local and systemic control. The acute toxicity of whole-body hyperthermia combined with whole-thorax irradiation was studied in dogs. Twenty-eight dogs received three 2-h whole-body hyperthermia (WBH) treatments at 42.0 degrees C deep rectal temperature. Twenty-four of these dogs were also randomized to receive radiation doses of 18, 22.5, 27, 31.5, 40.5 or 45 Gy. Irradiation was given in 1.5 Gy fractions over 6 weeks. Three WBH treatments were given to 28 dogs with all dogs surviving treatment. WBH was given on days 1, 22 and 40 of the 6-week interval. Thirty-one dogs received radiation doses of 18-49.5 Gy without WBH. Deep rectal temperature was maintained at 41.9 +/- 0.3 degrees C over 2 h with an average of 20 min outside the chamber for irradiation. Two dogs required intervention with emergency medications during WBH treatment. One of the two dogs developed permanent neurological injury. Continuous physiological monitoring was necessary for successful WBH. WBH plus thoracic irradiation was well tolerated. All dogs survived all treatments. A significant but transient increase in peripheral blood leucocytes and a decrease in platelet counts occurred after each WBH treatment. The addition of thoracic irradiation up to 45 Gy in 1.5 Gy fractions did not appear to alter the acute toxicity of WBH with the exception of an increase in the protein content of lung lavage fluids. In conclusion, multiple WBH treatments of 2 h at a target temperature of 42 degrees C in addition to thoracic irradiation up to 45 Gy in 1.5 Gy fractions was administered with only mild acute toxicities occurring. Core temperature could be maintained for up to 20 min outside of the WBH chamber which allowed irradiation to be given concurrently with hyperthermia at a core temperature of 42 degrees C +/- 0.1 degree C.

Animals↗
PubMedDate not supplied

Effects of intraoperative hyperthermia on peripheral nerves: neurological and electrophysiological studies.

The tolerance of peripheral nerves to heat may limit the heat dose which can be applied to tumours. This may be particularly important in intraoperative hyperthermia (IOHT) for pelvic and retroperitoneal tumours. Furthermore the effects of hyperthermia alone must be known before its effects can be assessed in combination with irradiation. In this study injury to sciatic nerves was evaluated in 30 beagle dogs for 1 year following IOHT. IOHT was performed using a water circulating hyperthermia device with multichannel thermometry system. Neurological and electrophysiological examinations were done before, during and after IOHT treatment. Electrophysiological examinations showed a significant decrease in sciatic nerve conduction velocity and potential amplitude immediately after 60 min of heating for all temperatures. The greatest decrease in conduction velocity was observed for a temperature of 45 degrees C. Full recovery of nerve conduction velocity was observed 3 weeks following hyperthermia for all dogs except for those exposed to 45 degrees C. Neurological findings correlated with electrophysiological results. All five dogs which had nerve exposed to 45 degrees C for 60 min had severe neurological changes, with recovery taking place between 3 and 11 months after treatment. Based on these results it appears that temperatures to the peripheral nerve exceeding 44 degrees C for 1 h are likely to cause significant, but not necessarily permanent, nerve injury.

Action Potentials↗
PubMedDate not supplied

Effects of intraoperative hyperthermia on canine sciatic nerve: histopathologic and morphometric studies.

Failure to achieve local control in the treatment of pelvic and retroperitoneal tumours results in a high rate of recurrences. The objective of intraoperative hyperthermia (IOHT) is to enhance the effect of intraoperative radiation therapy and to increase local tumour control. The tolerance of peripheral nerves to heat may limit the heat dose that can be applied to tumours. Histopathologic and histomorphometric changes of canine sciatic nerve after 60-min IOHT were studied in three groups of five dogs each for temperatures of 43, 44 and 45 degrees C. IOHT was performed using a water-circulating hyperthermia device with a multichannel thermometry system on surgically exposed sciatic nerve. Histopathologic and histomorphometric studies were done immediately, 3 weeks and 12 months after IOHT. Histologic changes observed immediately after treatment were minimal but at 3 weeks following 60-min 45 degrees C IOHT both axon and myelin loss and an increase in endoneurial fibrous tissue were observed. Twelve months after treatment a statistically significant decrease in axon, myelin and small vessel percentages as well as an increase in endoneurial and epineural connective tissue were observed for dog treated to 45 degrees C. Dog treated to 44 degrees C for 60 min had similar statistically significant but less severe changes. Twelve months after 43 degrees C IOHT for 60 min, nerve fibres appeared normal and endoneurial connective tissue was only increased mildly around small and medium-sized vessels. These results suggest that temperatures to the peripheral nerve > 44 degrees C for 60 min are likely to cause significant histopathologic changes that can be found 12 months after treatment. A hypothesis of the mechanism of heat injury to peripheral nerves was developed.

Animals↗
PubMedDate not supplied

Investigation of the fetal pulmonary inflammatory reaction in chorioamnionitis, using an in situ Y chromosome marker.

Chorioamnionitis is a frequent finding in the placenta in second-trimester premature labor. Seventy-six archival perinatal and fetal autopsies between 15 and 28 weeks of gestation with a morphologic diagnosis of chorioamnionitis were reviewed. Of the 76 cases, 52 (68%) had inflammatory cells in the lungs, which is higher than the reported incidence of clinical infection in neonates with chorioamnionitis. In 23 cases there were peribronchial lymphocytic hyperplasia and neutrophils in the airspaces, in 8 there was a lesser degree of interstitial inflammation as well as luminal neutrophils, and in 21 (40%) there were neutrophils in the airspaces only. To determine whether the neutrophils in the airspaces in the latter were maternal or fetal in origin, the lung sections of seven male fetuses in the group were examined by in situ hybridization for the Y repeat probe pHY 2.1, together with appropriate controls. Two of the tests were technical failures. The remaining five, and the positive controls, showed positivity for pHY 2.1 in 70-86% of luminal neutrophils. We conclude that luminal neutrophils in fetal lungs in this situation are fetal in origin.

Chorioamnionitis↗
PubMedDate not supplied

Association of extracolonic manifestations of familial adenomatous polyposis with acetylation phenotype in a large FAP kindred.

Familial adenomatous polyposis coli (FAP) has been shown to be associated with germline mutations of the adenomatous polyposis gene (APC) on chromosome 5. Extra-colonic manifestations also occur in FAP and include desmoid tumors, epidermoid cysts and osteomas. The combination of FAP with extracolonic symptoms is commonly referred to as Gardner's syndrome. It remains difficult, however, to predict which patients may have a propensity to develop extracolonic manifestations. The rapid acetylation phenotype is believed to be associated with an increased likelihood of sporadic colorectal cancer, whereas the slow acetylation phenotype is recognized as a predisposing factor for bladder cancer. The slow acetylation phenotype is caused by mutant alleles of the cytosolic enzyme N-acetyltransferase (NAT2). In this study, we determined the NAT2 genotype in members of one large FAP family and three smaller ones all of which had been shown to harbor the same germline APC gene mutation. We observed a significant correlation between slow acetylation genotypes and extracolonic manifestations of the disease. Rapid acetylation genotypes were not overrepresented in colorectal cancer cases in this family as compared to the frequency of this genotype in the normal Caucasian population.

Acetylation↗