Biosynthesis of radiolabeled pyrrolizidine alkaloids from Senecio jacobaea and Senecio vulgaris.
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Biomedical subjects
Publications and source records attributed to R L Reed.
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A case of total occlusion of the cervical internal carotid artery secondary to vasculitis is presented. Although vasculitis rarely causes total occlusion of the internal carotid artery, it directly contributed to a left hemispheric stroke in our patient. In the absence of the usual etiologic factors for internal carotid artery occlusion, vasculitis should be considered.
Transcutaneous oxygen (PtcO2) monitoring with miniaturized heated electrodes has been shown to continuously track arterial oxygen tension (PaO2) noninvasively in stable infants. However, the correlation between the two is less marked in unstable adults, and PtcO2 appears to be additionally influenced by perfusion. The ability of PtcO2 to detect alterations in cardiac index (CI) was evaluated in 19 critically ill adult patients. The PtcO2 was found to be influenced by the PaO2, the CI, and local vascular tone, with a rapid response time to changes in these variables. All instances of improvement in PtcO2 readings were associated with improvement in PaO2 or hemodynamic status. Because of its high sensitivity, continuous noninvasive PtcO2 monitoring should allow reduction in routine PaO2 and CI determinations. However, a decrease in PtcO2 requires immediate in-depth evaluation of the patient's PaO2 and CI because of its lack of specificity.
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The influence of Zn on the acute hepatotoxicity of pyrrolizidine alkaloids (PAs) was determined in male rats. Zinc, 72 mumol/kg as ZnCl2, was administered ip for 3 consecutive days, followed 16 h after the last dose by a single ip injection of purified mixed PAs (80, 120, or 160 mg/kg) obtained from tansy ragwort (Senecio jacobaea). Hepatotoxicity of the PAs was assessed by measuring the activities of plasma glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) and by histological examination of the liver. There was a dose-dependent increase in plasma GOT and GTP 24 h after PA administration, whereas no significant increase of these enzymes was seen after administering Zn alone. The 7-fold increase in plasma GOT and 12-fold increase in GPT after PA (120 mg/kg) were reduced to 2.4- and 2.1-fold, respectively, by Zn pretreatment. The PA-induced liver necrosis was either reduced in severity or abolished by Zn when the PA dose was 80 or 120 mg/kg. These results suggest a protective effect of Zn against PA hepatotoxicity. The protective effect was associated with a marked increase in liver metallothionein and a significant decrease in hepatic cytochrome P-450 content, aminopyrine N-demethylase activity, and in vitro microsomal conversion of the PAs to pyrroles. Liver nonprotein sulfhydryls were unchanged. The possible role of metallothionein in the sequestration of pyrrole metabolites merits further investigation.
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The arteriovenous fistula (AVF) is the choice made of access to the circulation in patients having chronic hemodialysis. AVFs are also used in patients having repeated courses of intravenous chemotherapy. This relatively simple operation can result in considerable morbidity if improperly done. The technics used in our center, which result in a high patency rate, are described. Maneuvers designed to reduce the resistance to flow and increase the minute flow through the fistulas are stressed.
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STUDY OBJECTIVE: To determine the prevalence of early (in 14 days or less) readmissions to the hospital, and to identify risk factors for readmission. DESIGN: Matched case-control. Cases (n = 155) were readmitted to the hospital within 14 days of a hospital discharge, while controls (n = 155) were not. Controls and cases were matched by week of hospital discharge. PATIENTS: Two-year sequential sample of male veterans aged 65 years and over admitted to the Seattle Veterans Affairs (VA) Medical Center. MEASUREMENTS: Data about 31 potential risk factors were abstracted from the medical records. RESULTS: Three risk factors associated with readmission risk were identified and include two or more hospital admissions in the previous year [odds ratio (OR) = 3.06], any medication dosage change in the 48 hours prior to discharge (OR = 2.34), and a visiting nurse referral for follow-up (OR = 2.78). One protective factor--discharge from the geriatric evaluation unit (GEU) (OR = 0.09)--was also determined. CONCLUSIONS: Early unplanned readmissions were frequent at this VA facility. Since the strongest risk factor for readmission was the number of admissions in the previous year, readmissions appeared most commonly among high utilizers of inpatient VA care. This risk factor and others may be useful in identifying a group at high readmission risk, which could be targeted in intervention studies. The reduced readmission rate associated with the GEU suggests one potential intervention to decrease readmission risk.
Monocrotaline (MCT) is a pyrrolizidine alkaloid which has been shown to induce immunotoxicity in mice. We hypothesized that metabolic activation of MCT by mixed-function oxygenases (MFO) to dehydromonocrotaline (MCTP) is a prerequisite for its immunotoxicity, as has been shown for other toxic effects of MCT. To test this hypothesis, we compared the in vitro immunotoxic potency of MCT and MCTP to suppress the in vitro antibody response to SRBC and the blastogenic response to B and T cell mitogens. In addition, the effects of in vivo modulation of MFO activities on the immunotoxicity of MCT was examined using phenobarbital (PB) to increase and chloramphenicol (CP) to decrease MCTP production. Results showed that in vitro exposure of splenic lymphocytes to MCT or MCTP produced significant suppression of the antibody and blastogenic responses. MCTP was 200-400-fold more potent than MCT. No metabolism of MCT by splenic cells was detectable, suggesting that unmetabolized MCT is capable of inducing immunotoxicity. In vivo studies showed that, while treatment of mice with PB or CP produced significantly increased and decreased MCTP production by liver microsomes, neither PB or CP treatment significantly altered the immunotoxic potency of MCT. Thus, while the MCTP metabolite is directly immunotoxic in vitro and much more potent than MCT, a role for the MCTP metabolite in MCT immunotoxicity in vivo could not be demonstrated.
TOPIC: Abdominal compartment syndrome (ACS) in blunt and penetrating abdominal trauma. PURPOSE: To review the clinical manifestations, pathophysiology, and nursing management of patients with ACS. SOURCES: Published literature, case study. CONCLUSIONS: Trauma nurses play a key role in early identification and management of ACS. Priorities include knowledge of signs and symptoms, methods of measurement of ACS; specifics of wound care, psychosocial interventions, and key factors in discharge planning.
BACKGROUND: Little is known about the rate of institutionalization and health status of nursing home (NH) type patients living in the Middle East. This study was set in the Al-Ain Medical District, a geographically discrete region of the United Arab Emirates, a country with a developing economy located on the shores of the Arabian Gulf. NH-type patients were defined as people aged 60 years and older who were admitted to a hospital or a long-term institutionalized setting for at least 6 weeks and with no evidence of an expectation of discharge at the time of the evaluation. OBJECTIVE: To determine the clinical, functional, cognitive, and nutritional status of NH-type patients living in a defined community within a developing country. METHOD: Cross-sectional survey. RESULTS: All NH-type patients were identified, and all were included in this study (n = 47, 100% participation rate). All were located within three public institutions, none of which was a dedicated NH facility. The rate of institutionalization was 7.0-14.0 per 1,000 people aged 65 or older. The age distribution was 30% (60-74 years), 49% (75-84 years), and 21% (85+ years). The length of stay was 3.8 years. The female:male ratio was 1.6. All except 1 had a neurological disorder, and 89% had dementia. The cognitive deficits were severe with only 61% alert, 41% able to speak, 17% orientated in place, and 15% orientated in time. The functional status was also poor: 98% received assistance with all instrumental activities of daily living, 85% received assistance with five activities of daily living, and 94% were bed bound. The nutritional status was also impaired with a mean body weight of 45 +/- 14 kg and a mean albumin level of 3.1 +/- 0.6 g/dl. When compared with the USA data from the National Center for Health Statistics, the study population was younger, had a longer length of stay, a lower female:male ratio, a higher rate of neurological diseases and dementia, and were far more dependent and disoriented. The rate of institutionalization was one sixth to one third of that in the USA. CONCLUSION: From these data we concluded that this region has a distinctly different population of institutionalized older people who demonstrate greater impairments in all domains of health status.
The effects of a 60% small-bowel resection on postoperative visceral organ glucose exchange was studied in order to gain further understanding of the role of the intestinal tract as a supplier of gluconeogenic substrate to the liver following operative stress. We determined the flux of glucose across the gastrointestinal tract, liver, and kidneys in 20 postoperative dogs. With enterectomy portal bloodflow and total hepatic bloodflow were diminished by 33% and 25%, respectively. Arterial glucose was slightly lower in the enterectomized group 6 hr following the operation. Intestinal glucose uptake was diminished by more than 50% in the enterectomized dogs (p less than 0.01). Net hepatic glucose release fell from 22 mumole/kg/min to 8 mumole/kg/min (p less than 0.01). In control animals the kidney was an organ of slight glucose uptake while in the enterectomized group, the kidney released glucose at the rate of 4.1 mumole/kg/min (p less than 0.05). The data suggest that the gut is an important supplier of gluconeogenic precursors to the liver which are used to support gluconeogenesis in the postoperative period. The ability of the kidney to accelerate glucose production in this setting suggests that metabolic adaptation and cooperation between organs occurs during organ absence or dysfunction which helps preserve glucose homeostasis.
Manure use on cropland has raised concern about nutrient contamination of surface and ground waters. Warm-season perennial grasses may be useful in filter strips to trap manure nutrients and as biomass feedstock for nutrient removal. We explored the use of 'Alamo' switchgrass (Panicum virgatum L.) in a biomass production-filter strip system treated with dairy manure. We measured changes in extractable P in the soil, NO3 -N in soil water, and changes in total reactive P and chemical oxygen demand (COD) of runoff water before and after a switchgrass filter strip. Five rates of dairy manure (target rates of 0, 50, 100, 150, and 200 kg N ha(-1) from solid manure in 1995; 0, 75, 150, 300, and 600 kg N ha(-1) from lagoon effluent in 1996 and 1997) were surface-applied to field plots of switchgrass (5.2 by 16.4 m) with a 5.2- by 16.4-m switchgrass filter strip below the manured area. Yield of switchgrass from the manured area increased linearly with increasing manure rate in each year. Soil water samples collected at 46 or 91 cm below the soil surface on 30 dates indicated < 3 mg L(-1) of NO3-N in all plots. Concentrations of total reactive P in surface runoff water were reduced an average of 47% for the 150 kg N rate and 76% for the 600 kg N rate in 1996 and 1997 after passing through the strip. Manure could effectively substitute for inorganic fertilizer in switchgrass biomass production with dual use of the switchgrass as a vegetative filter strip.
The bone mineral density (BMD) of the calcaneus was estimated in 185 young women from the United Arab Emirates, using SAHARA ultrasound. All participants completed a questionnaire on factors potentially associated with osteoporosis. In all, 29 (15.7%) of the women were classified as having osteopenia and none as having osteoporosis. Participants with osteopenia were more likely to have had a later onset of menarche, irregular periods, lower body mass index, and a positive family history of osteoporosis. Only late menarche and low body mass index, however, were independent predictors of osteopenia.
Changes in use by the elderly of the emergency department of a major hospital in Al-Ain in the years 1989 and 1999 were examined. All patients aged 65 years or older who attended the emergency room were included in this cross-sectional survey. Patient numbers rose from 321 in 1989 to 1347 in 1999 with no significant change in the female to male ratio of 0.78 or the mean age of the elderly attendees 72.9 +/- 7.4 years. Attendance rose 5.4 fold while non-urgent attendance rose 14.7 fold, demonstrating rising use but falling illness severity over time.
We evaluated a diabetic mini-clinic by assessing adherence to American Diabetes Association guidelines and changes in glycosylated haemoglobin levels. Of 1063 patients, 721 were multiple attenders. Single and multiple attenders showed no significant differences in age, sex, time since diagnosis or body mass index. Female and male multiple attenders showed significant declines in glycosylated haemoglobin levels over the first 12 and 18 months respectively. After 2 years, these levels were similar to those at entry to the clinic. The clinic's compliance with standard measurement guidelines was high. The diabetic mini-clinic model, which is effective in industrialized countries, was equally effective in this setting.