Biomedical subjects
Publications and source records attributed to C Duncan.
The authors discuss the need for Do Not Resuscitate policies in psychogeriatric wards, the process of consulting Maori when formulating such policies and some legal considerations when applying do not resuscitate policies. The reasons for the need to consult with Maori when developing mental health services for the elderly are emphasised.
High concentrations of nitrite present in saliva (derived from dietary nitrate) may, upon acidification, generate nitrogen oxides in the stomach in sufficient amounts to provide protection from swallowed pathogens. We now show that, in the rat, reduction of nitrate to nitrite is confined to a specialized area on the posterior surface of the tongue, which is heavily colonized by bacteria, and that nitrate reduction is absent in germ-free rats. We also show that in humans increased salivary nitrite production resulting from nitrate intake enhances oral nitric oxide production. We propose that the salivary generation of nitrite is accomplished by a symbiotic relationship involving nitrate-reducing bacteria on the tongue surface, which is designed to provide host defence against microbial pathogens in the mouth and lower gut. These results provide further evidence for beneficial effects of dietary nitrate.
Broad spectrum antibiotics are known to predispose towards oral candidiasis and gastroenteritis. Oral nitrite synthesis by commensal bacteria may be important in protecting the mouth and lower intestine from pathogenic organisms, including Candida albicans. The effect of 2 days administration of the broad spectrum antibiotic amoxycillin on salivary nitrite concentration, following a 200 mg potassium nitrate oral load, was studied in 10 healthy volunteers. The Cmax fell by 40% and the AUC was reduced by 1227 microM h (43%, 95% CI 273, 2181, P < 0.006) in the antibiotic treated group when compared with control. These findings suggest that destruction of nitrate reductase containing bacteria in the mouth by antibiotics may explain an increased incidence of infection with Candida and other pathogens.
STUDY OBJECTIVE: To establish whether regional variations in psychiatric morbidity in Britain constitute a distinctive geography of mental health arising from factors that are context-specific at area level or whether these variations are an artifact generated by sampling fluctuations and differing population compositions in areas. DESIGN: Multilevel modelling techniques were applied to data from the 1984-85 health and lifestyle survey. The outcome was the prevalence of psychiatric morbidity as recorded by the application of the general health questionnaire in this survey. SETTING: The analysis was undertaken simultaneously at the individual level, electoral ward level, and regional level for England, Wales, and Scotland. PARTICIPANTS: A total of 6572 adults were selected from the electoral register. MAIN RESULTS: Regional variations were detected in crude aggregate general health questionnaire scores but these were found to be the result of sampling fluctuations and varying regional population compositions rather than higher level contextual effects. There was certainly no evidence of a clear north-south distinction in psychiatric morbidity as was suggested by earlier work. In addition, the local neighbourhood did not seem to have any importance beyond the type of people who lived there. A number of individual characteristics was shown to be associated with mental wellbeing but a large degree of individual variation remained unexplained. CONCLUSIONS: In terms of low level psychiatric disturbance it seems that the characteristics of individuals have greater importance than the characteristics of areas, although the latter may still operate as important mediating factors. Multilevel modelling represents a robust statistical method of examining area variations in health outcomes and further work needs to be conducted, particularly on more serious psychiatric conditions.
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Two cases of neurocutaneous melanosis are presented. MR showed hyperintense areas in the brain on short-repetition-time/short-echo-time sequences, compatible with intraparenchymal melanin deposits. No leptomeningeal abnormality was seen.
STUDY OBJECTIVE: To determine the pathogenesis and clinical course of lactic acidosis in adults receiving standard medical care. DESIGN: Placebo arm of a 5-year prospective, randomized, blinded study comparing placebo and dichloroacetate as specific lactate-lowering therapy. Each patient received intravenous saline placebo in addition to conventional therapy. SETTING: Intensive care units of 10 tertiary care hospitals in North America. PATIENTS: One hundred twenty-six patients with lactic acidosis, defined as arterial blood lactate greater than or equal to 5 mmol/L and either arterial pH of less than or equal to 7.35 or base deficit greater than 6 mmol/L. Patients were followed for up to 6 months. MEASUREMENTS AND MAIN RESULTS: Mean +/- SD demographic entry data for 126 patients included: age 56 +/- 17 years, lactate 10.4 +/- 5.5 mmol/L, pH 7.24 +/- 0.14, calculated base deficit 14.1 +/- 5.4, arterial systolic blood pressure 103 +/- 29 mm Hg, Glasgow Coma score 7.9 +/- 4.9, and APACHE II score 19.2 +/- 8.1. Despite fluids and pressors, 32% of patients had systolic blood pressures of less than or equal to 90 mm Hg in association with sepsis (59%), cardiac failure (18%), or hemorrhage (18%). The most common causes of lactic acidosis in the absence of shock were sepsis (49%), liver disease (15%), and respiratory failure (12%). The median survival was 38.5 hours. Survival at 24 hours was 59%. Arterial pH predicted 24-hour survival better than base deficit or bicarbonate level. Percent survival was 41% at 3 days and 17% at 30 days. Only 21% of patients survived to leave the intensive care unit, and 17% were discharged from the hospital. In patients receiving sodium bicarbonate, neither acid-base nor hemodynamic status improved. CONCLUSIONS: In this first prospective study of the clinical course of acute lactic acidosis in adults, nearly all subjects had both hemodynamic and nonhemodynamic (metabolic) underlying causes, many of which independently predicted survival and most of which were refractory to standard care.
The Complications Screening Program (CSP) is a method using standard hospital discharge abstract data to identify 27 potentially preventable in-hospital complications, such as post-operative pneumonia, hemorrhage, medication incidents, and wound infection. The CSP was applied to over 1.9 million adult medical/surgical cases using 1988 California discharge abstract data. Cases with complications were significantly older and more likely to die, and they had much higher average total charges and lengths of stay than other cases (P < 0.0001). For most case types, 13 chronic conditions, defined using diagnosis codes, increased the relative risks of having a complication after adjusting for patient age. Cases at larger hospitals and teaching facilities generally had higher complication rates. Logistic regression models to predict complications using demographic, administrative, clinical, and hospital characteristics variables, had modest power (C statistics = 0.64 to 0.70). The CSP requires further evaluation before using it for purposes other than research.
An enzyme capable of the oxidation of hydroxylamine to nitrite was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The absorption spectra in cell extracts, electron paramagnetic resonance spectra, molecular weight, covalent attachment of heme group to polypeptide, and enzymatic activities suggest that the enzyme is similar to cytochrome P-460, a novel iron-containing protein previously observed only in Nitrosomonas europaea. The native and subunit molecular masses of the M. capsulatus Bath protein were 38,900 and 16,390 Da, respectively; the isoelectric point was 6.98. The enzyme has approximately one iron and one copper atom per subunit. The electron paramagnetic resonance spectrum of the protein showed evidence for a high-spin ferric heme. In contrast to the enzyme from N. europaea, a 13-nm blue shift in the soret band of the ferrocytochrome (463 nm in cell extracts to 450 nm in the final sample) occurred during purification. The amino acid composition and N-terminal amino acid sequence of the enzyme from M. capsulatus Bath was similar but not identical to those of cytochrome P-460 of N. europaea. In cell extracts, the identity of the biological electron acceptor is as yet unestablished. Cytochrome c-555 is able to accept electrons from cytochrome P-460, although the purified enzyme required phenazine methosulfate for maximum hydroxylamine oxidation activity (specific activity, 366 mol of O2 per s per mol of enzyme). Hydroxylamine oxidation rates were stimulated approximately 2-fold by 1 mM cyanide and 1.5-fold by 0.1 mM 8-hydroxyquinoline.
A number of commentators have argued that there is a distinctive geography of health-related behaviour. Behaviour has to be understood not only in terms of individual characteristics, but also in relation to local cultures. Places matter, and the context in which behaviour takes place is crucial for understanding and policy. Previous empirical research has been unable to operationalize these ideas and take simultaneous account of both individual compositional and aggregate contextual factors. The present paper addresses this shortcoming through a multi-level analysis of smoking and drinking behaviours recorded in a large-scale national survey. It suggests that place, expressed as regional differences, may be less important than previously implied.
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We prospectively examined 11 patients with magnetic resonance imaging-documented infarction in the paramedian thalamopeduncular region, which is supplied by the superior mesencephalic and posterior thalamosubthalamic arteries. Variations in the size and rostral-caudal extent of infarction correlated with the following three clinical patterns: (1) With unilateral paramedian mesencephalic infarction, an ipsilateral third nerve paresis was accompanied by mild contralateral hemiparesis or hemiataxia. Contralateral ptosis and impaired upgaze were observed in two patients; one of them showed additional damage to the posterior commissure. (2) With bilateral infarction in the thalamopeduncular junction, involving the mesencephalic reticular formation, supranuclear vertical gaze defects were accompanied by impaired consciousness or memory, and mild aphasia in some patients. Persistent amnesia was observed only when the dominant anterior nucleus or mamillothalamic tract was damaged. (3) With larger thalamopeduncular infarcts, partial or complete third nerve paresis was combined with supranuclear gaze disturbance and delayed contralateral tremor. An unusual gaze disorder, a variant of the vertical "one-and-a-half syndrome," occurred with a small strategically placed lesion at the thalamopeduncular junction, best explained by selective damage to supranuclear pathways or partial nuclear involvement. The primary cause of these infarctions was embolism to the basilar apex or local atheroma at the origin of the posterior cerebral artery.
The mobilization of a nonconjugative plasmid (pCaT) that mediates chloramphenicol resistance in Lactobacillus plantarum caTC2R was achieved by comobilization with the conjugative plasmid pAM beta 1. The conjugation studies confirmed that the 8.5-kb pCaT in L. plantarum caTC2R contains the gene responsible for chloramphenicol resistance and that the plasmid has several unique restriction sites which make it useful for genetic studies in Carnobacterium spp. Cloning studies showed that the gene responsible for chloramphenicol resistance is located in the 2.6-kb EcoRV-SalI region of pCaT. This was confirmed by probing the 3.0-kb BglII fragment of pCaT with a biotin-labeled 1.6-kb BstEII-HpaII fragment from the streptococcal-derived plasmid pVA797(Cmr). Expression of chloramphenicol resistance in Carnobacterium as well as in other Lactobacillus species was achieved by electrotransformation using donor DNA from pCaT.
A 28-year-old female with a diagnosis of multiparity was scheduled for laparoscopic tubal ligation. The patient had an unremarkable medical history, except that she had been a pack-a-day smoker for the past 10 years and had experienced a recent upper respiratory infection. General anesthesia was accomplished without incident, and insufflation of the abdomen with carbon dioxide (CO2) gas was begun. During insufflation the end tidal carbon dioxide (ETCO2) level dropped dramatically, ECG changes were noted, and vital signs deteriorated with the subsequent development of cardiac arrest. The patient was successfully resuscitated, fully awake, and extubated approximately 1 hour after the incident. A CO2 embolus caused by CO2 insufflation was suspected. In laparoscopic procedures, the use of CO2 gas is an efficient and inexpensive means of improving visualization of the abdominal cavity. The effect of CO2 insufflation on the patient should be given special consideration in these cases. Although serious complications associated with the use of CO2 gas are rare, such procedures must not be viewed with complacency. A protocol for the management of emergency situations should be developed and reviewed.
An audit of all 466 non-insulin-dependent diabetic patients first diagnosed between 1979 and 1981 at a district general hospital in Fife was carried out. This involved the retrospective examination of their medical records and follow up of the patients to 1989 with particular reference to mortality and the development of complications. Throughout the study period the hospital, which has a total catchment population of about 160,000, operated a policy of encouraging all newly diagnosed diabetics to be referred to hospital for assessment and management. One hundred and eighty-nine diabetics (41%) died during the follow-up period. In both sexes they had an excess mortality, compared with the Scottish population of the same sex and age in 1981, of approximately 20% at 40 years of age. This increased to double or above between the ages of 60 and 70. The principal underlying cause of death was attributed to macrovascular disease, including 70 (37%) certified as ischaemic heart disease, 33 (17%) as cerebrovascular disease and 10 (5%) as other diseases of circulation. Thirty-five (8%) diabetics developed macrovascular and 23 (5%) microvascular complications during follow-up. We conclude that non-insulin-dependent diabetics have a high mortality, principally from macrovascular causes. A simple audit of mortality is suitable for measuring their care. General practitioner diabetic mini-clinics for the follow-up of non-insulin-dependent diabetic patients will have smaller numbers of patients to review compared with the traditional follow-up clinics seen in most district general hospitals. These may allow earlier detection and treatment of hypertension and dyslipidaemia.(ABSTRACT TRUNCATED AT 250 WORDS)
Small cell lung cancer (SCC) has the most rapid growth rate of the four cell types and metastasizes early. Present imaging modalities for staging include chest x-ray, CT, MRI and bone scans. In this preliminary study, we assessed the clinical role of 99mTc-monoclonal antibody (MOAB) scintigraphy in five patients with histologically proven SCC. Each patient was infused with 20-30 mCi of 99mTc labeled Fab fragment of MOAB (NR-LU-10, NeoRx, Seattle, Wash.). Total body simultaneous anterior and posterior images were obtained 14-16 h post injection. SPECT images of the chest were obtained through a 360 degrees rotation of the gamma camera and recorded on a 62 x 64 x 16 matrix. Images (1.2 cm thick) were generated in transaxial, sagittal and coronal views. Fourteen of fifteen chest lesions detected by CT were confirmed by 99mTc MOAB scintigraphy. Scintigraphy detected one additional chest lesion not seen by CT. Scintigraphy failed to detect a brain lesion (2 cm), a chest lesion, and two adrenal lesions, all of which were seen by CT. In one patient with multiple (more than 10) lesions in the liver, both scintigraphy and CT detected all lesions. Three spine lesions seen on 99mTc MDP scan and positive for metastasis on MRI concentrated 99mTc MOAB, but two rib lesions seen on 99mTc MDP bone scan did not concentrate 99mTc MOAB. It is concluded from these preliminary results that the potential usefulness of 99mTc MOAB scintigraphy as a complementary imaging modality in the staging of small cell lung cancer should be investigated further.
We compared the counseling behaviors of two groups of health maintenance organization physicians: one group received training about smoking cessation counseling; the other group received the same training plus staff support and appointment time specially designated for follow-up of smokers. We interviewed patients after their office visits to measure smoking counseling. The group receiving staff support and designated follow-up time counseled more and made more follow-up appointments about smoking.