Biomedical subjects
R M Scott
Publications and source records attributed to R M Scott.
Evidence of a role for the peripheral chemoreceptors in the ventilatory response to doxapram in man.
In seven normal subjects premedicated with atropine and pethidine and lightly anesthetized with thiopentone, the ventilatory response evoked by doxapram 20 mg i.v. was delayed on average from 15.7 s to 23.0 s when changing from air to oxygen breathing. Mean VE, immediately after the administration of doxapram was increased by 3.3 litre and 1.9 litre when breathing air and oxygen respectively. These findings indicate that doxapram has an effect on the peripheral chemoreceptors and are consistent with drug activity on both peripheral and central respiratory control mechanisms.
Transmission of hepatitis B virus to gibbons by exposure to human saliva containing hepatitis B surface antigen.
A pool of whole-mouth saliva collected from five human carriers of hepatitis B surface antigen, subtype adr, was found to contain antigen particles with mean diameters of 23.3 and 41.8 nm as seen by immune electron microscopy. Two gibbons received subcutaneous injections of the pooled saliva and developed serological and, in at least one animal, biochemical evidence of hepatitis B virus infection at 12 and 22 weeks, respectively. Although none of eight other gibbons that were exposed by the nasal or oral routes were infected, the experiment demonstrated that human saliva can serve as a vehicle for the transmission of hepatitis B virus.
192Ir over-exposure in industrial radiography.
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Visual loss from optochiasmatic arachnoiditis after tuberculous meningitis. Case report.
While recovering from tuberculous meningitis, a 5-year-old boy developed a profound visual deficit because of optochiasmatic arachnoiditis. Following microneurosurgical decompression of the optic nerves and chiasm, prompt visual recovery occurred.
Computed tomography in spinal dysraphism.
Computed tomography of the spine has been used to evaluate patients with spinal dysraphism. With this technique, the nature of soft-tissue masses can often be correctly diagnosed and the underlying bony anomalies clarified.
Spontaneous thrombosis of an intracranial aneurysm during treatment with epsilon aminocaproic acid.
The authors report spontaneous thrombosis of a middle cerebral artery aneurysm in a patient receiving the anti-fibrinolytic agent, epsilon aminocaproic acid. Intense vasospasm and profound neurologic deficit accompanied the initial hemorrhage. Follow-up angiography two, four and ten weeks following the initial hemorrhage demonstrated occlusion of the aneurysm and progressive thrombosis of a middle cerebral artery branch despite the disappearance of vasospasm. The patient had a persistent hemiparesis.
Intensive radiotherapy of locally advanced bladder cancer.
Over a 10-year period, 82 patients with locally advanced bladder cancer were treated by one of two intensive radiotherapy routines. They received either 320 rads/day for 11 consecutive treatment days; or two sets of 320 rads/day for six consecutive treatment days each, with a three-week rest interposed between sets. Side effects were briefly annoying, but quite tolerable. Good quality palliation was obtained. Uncorrected survival rates for the entire series were 48% at 1 year, 20% at 3 years, and 13% at 5 years.
Unusual pelvic masses: a comparison of computed tomographic scanning and ultrasonography.
Four unusual pelvic masses, studied by CT and gray scale ultrasonography, demonstrate the comparative values of these modalities for this area of the body. In each instance a significant contribution to the diagnosis was made by one or both techniques. The ultrasound study provides a somewhat better differentiation of solid from cystic lesions, but the CT scan denotes to best advantage the anatomy of the area, and provides a means of viewing bone as well as soft tissue detail.
Electron beam therapy in head and neck tumors.
Electron beam therapy with its high energy capabilities appears promising as a therapeutic modality in head and neck neoplasms. Over a 10-year period, 153 cases of head and neck neoplasms involving the alveolar ridge, floor of mouth, buccal mucosa, retromolar trigone, tonsil, parotid, tongue, and pharynx were treated. The pharyngeal group was removed from consideration because of the unsuitability of this lesion for single port therapy. Normal standard doses and time-dose fractions are included as a basis for treatment comparison, and the influence of stage on survival is noted. Survival and tolerance of this form of treatment is comparable to photon therapy and may in fact result in fewer complications.
Effect of chemical protectors on the response of the intestine to roentgen or fission neutron irradiation.
The monosodium salt S-1-(2-hydroxy-3-amino) propylphosphorothioic acid (WR-77913) and S-2-amino ethylisothiuronium-Br-HBr (AET) were tested for protective effects against 4 MeV roentgen irradiation and fission neutrons in the mouse intestine. The parameters tested were intestinal crypt survival, lethality and intestinal crypt cellularity. The results showed both compounds to be good protectors in animals. The crypt survival curve for roentgen-irradiated mice treated with AET was parallel to that of the untreated group and was displaced to the right by 4.88 Gy (488 rad). Protection from neutron irradiation was less effective with a displacement of only 0.69 Gy (69 rad). Pretreatment with WR-77913 increased the slope of the crypt survival curve in roentgen-irradiated mice. This was also seen to a much less extent in neutron-irradiated animals. The displacements of the curves (at 50 per cent crypt survival) were found to be 5.15 and 1.02 Gy (515 and 102 rad) for roentgen and neutron irradiation, respectively. The lethality experiments showed a dose modification factor (DMF) of 1.42 for both drug-tested groups of roentgen-irradiated mice. The dose modification factors for fission neutron irradiated mice were 1.48 and 1.2 for WR-77913 and AET-treated mice, respectively. The effect of these protectors of crypt cellularity is also discussed.
Myxochondrosarcoma of the fourth ventricle. Case report.
The authors report a case of myxochondrosarcoma of the fourth ventricle. The tumor was heavily calcified and proved impossible to remove at surgery. Histological examination revealed areas of loose fibroblastic tissue, hyaline cartilage, osteoid, and bone. It is postulated that the tumor arose from the stroma of the choroid plexus.
Isolation of Langat virus from Haemaphysalis papuana Thorell in Thailand.
A strain of Langat virus (LGT), T-1674, was isolated from a pool of Haemaphysalis papuana Thorell collected in the forest of Khao Yai National Park in Central Thailand. The isolated virus was found to have growth and antigenic similarity to the prototype Langat strain (TP-21). This is the first report of a natural infection of Haemaphysalis ticks with LGT and of the isolation of this arbovirus in Thailand. The wide distribution of known vectors of LGT in Thailand suggests that the virus may be present in other areas of the country.
Epidemic influenza in a hill tribe of northwest Thailand.
An investigation of an epidemic of respiratory disease in a remote region of northwest Thailand revealed Influenza A/H3N2 as the etiologic agent. This epidemic would not have been recognized were it not for an unusual increase in respiratory disease following a meeting attended by residents of many villages. The influenza strains isolated most closely resembled A/Port Chalmers/1/73 when tested by hemagglutination inhibition but showed consistent antigenic differences when tested by quantitative neutralization. It is suggested that the differences noted between this strain and influenza viruses isolated elsewhere may have been due to the sequential transmission of influenza through partially immune people.
Shock syndrome in primary dengue infections.
During 1974, 114 patients with dengue hemorrhagic fever were studied at the Bankok Children's Hospital. Over 40% of the patients had dengue shock syndrome. Five fatal cases were included in the study. Primary dengue infections were identified by absent or low titered antibodies in acute sera and the sequential development of IgM antibodies followed by IgG antibodies during convalescence. Three patients, aged 4,8, and 12 years, had primary dengue infections with shock. Although no convalescent sera could be tested two other patients, aged 7 to 12 years, with fatal disease also appeared to have primary infections. At the time of shock patients with primary infections had subnormal concentrations of complement factor 3. The data show that in older children dengue shock syndrome associated with complement depression can occur during primary as well as secondary infections.
The effect of S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR 2721) on intestinal crypt survival. II. Fission neutrons.
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Subtypes of hepatitis B surface antigen in Southeast Asia.
The prevalences of hepatitis B surface antigen (HBs Ag) subtypes in Thais, Cambodians, and Vietnamese were compared with the prevalences in Americans residing in Southeast Asia. HBs Ag was found with approximately equal frequency in Thai (43 percent) and American (39 percent) patients with hepatitis. However, higher prevalences of HBs Ag were found in asympotomatic Thais (9.5 percent), Cambodians (11.9 percent), and Vietnamese (14.3 percent) than in asymptomatic Americans (0.7 percent). Among asymptomatic Thais, the ratio of HBs Ag/adr to HBs Ag/adw was approximately 10:1, with one exception: adw was not detected in a rural population of northern Thailand. The y determinant was not found in Thais. In contrast, both d and y determinants were found in Americans. These observations conform to a geographic pattern, with ad as the predominant combination in the Far East. In Southeast Asia determinants w and r are more useful epidemiologic markers than y and d.
An epidemiologic study of hepatitis B virus in Bangkok, Thailand.
Residents of a randomly selected sample of households in a low-income housing project in Bangkok were studied between July 1971 and April 1972. Prevalence of hepatitis B antigen (HBs Ag) in July 1971 was 8.2% in 697 persons age one year and older and changed little with age. Prevalence of antibody to HBs Ag (anti-HBs) was much higher in all age groups and was 46% overall. The prevalence of HBs Ag was higher in males than females from ages 10-29 years and the prevalence of anti-HBs was higher in males up to age 60. The HBV (combined HBs Ag and anti-HBs) age prevalence distribution in July 1971 revealed that over 20% of the children 1-4 years of age had serologic evidence of infection and that the prevalence rose rapidly with age reaching a plateau between 60-70% after age 15. During the nine months of serologic surveillance 13% of individuals acquired either HBs Ag or anti-HBs and 7% lost serologic evidence of HBV infection. The study data suggest that most HBs Ag positive persons are long-term antigen carriers, that their numbers and spatial distribution may be sufficient to account for the wide-spread transmission of HBV in this population, that close person-to-person contact with carriers is probably the most important mode of HBV transmission, and that the susceptibility to becoming an HBs Ag carrier is probably genetically determined.