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Biomedical subjects

R F Smith

Publications and source records attributed to R F Smith.

At least 109 records · Page 6Linked to original sources
PubMed1989

Toxicology screening in urban trauma patients: drug prevalence and its relationship to trauma severity and management.

Although toxicology screening is often used when treating trauma patients, its utility and significance remain controversial. Data from 623 toxicology screens performed in urban trauma center patients with mental status alterations are reported. The study patients were predominantly black and male, with a mean age of 32 (+/- 22) years. Overall, 86% of screens were positive. Substances of abuse, including ethanol, were noted in 525 (84%) of urine toxicology screens. Ethanol, cannabinoids, and cocaine were the drugs most commonly found in urine, with positivity noted in 53%, 37%, and 34% of screens. Serum analysis was 44% positive, with ethanol noted in 41% of patients. In blacks, the odds ratio of illicit drug use before trauma ranged from 1.9 to 4.2 (p less than 0.005), and in those aged 17 to 40 years, the odds ratio for illicit urine drugs ranged from 4.7 to 16.8 (p less than 0.001). In patients older than 40 years, the odds of a positive serum ethanol level were 1.7 times greater than in younger patients, and a level above 300 mg% was 3.8 times more likely in this age group (p less than 0.001). When serum ethanol was detected, the odds ratio of a head injury was 1.4 relative to patients without serum ethanol (p less than 0.06), and the odds ratio for abdominal injury was 1.6 for patients with serum ethanol (p less than 0.03). The odds of a TS less than 12 were 1.8 (p less than 0.05), and the odds of a GCS less than 12 were 3.3 (p less than 0.001) with ethanol levels greater than 100 mg%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Lithium as a normal metabolite: some implications for cyclotron resonance of ions in magnetic fields.

Cyclotron resonance of ions has been proposed as a mechanism by which weak, extremely-low-frequency (ELF) electromagnetic fields can act on biological systems. Critics of a mechanism predicated on resonance of lithium have argued that this element is virtually absent from the internal milieu of mammals and otherwise plays no role in the normal physiological functioning of the organism. Sophisticated techniques of trace-element analysis have recently revealed that lithium is a normal constituent of tissues of assayed mammals, including those of rats and human beings. There is evidence, too, that lithium is an important, biologically-active element. Cyclotron resonance may or may not be a mechanism by which ELF- and static-magnetic fields at low strengths combine to affect the organism, but rejection of this mechanism on the grounds that lithium is absent or is physiologically inadequate is unwarranted. Lithium is normally present and is metabolically active in many tissues, especially those of the neuroendocrine system.

Animals↗
PubMed1988

Recurrent femoral anastomotic aneurysms. A 30-year experience.

Of the 1771 patients who underwent aortofemoral bypass grafting (AFB) during the 30-year period of 1957-1986, 43 noninfected recurrent femoral anastomotic aneurysms (RFAA) developed in 28 patients. Thirty-six RFAAs were treated surgically, with one death and no amputations occurring. Seven small RFAAs (less than 2.0 cm) were treated expectantly without complications. Using univariate and multivariate analyses, clinical characteristics and other factors influencing results in patients with RFAAs were compared to two control groups: patients who had undergone AFB without the development of femoral anastomotic aneurysms (FAAs) and patients who had undergone FAA repairs but without recurrence of FAA. Comparative analyses suggested: 1) local wound complications after initial AFB or FAA repair increased risk of a RFAA (p less than 0.03); 2) development of an FAA within 4.5 years after AFB increased risk of a RFAA (p less than 0.0002); 3) following an FAA repair, risk of a RFAA was almost three times greater for women than for men (p less than 0.05); and 4) patients with arteriosclerotic heart disease (ASHD) were less likely to develop RFAA than those without ASHD (p less than 0.05). Among the 20 additional variables analyzed--including hypertension, smoking, diabetes mellitus, and etiology of primary vascular disease--no statistically significant influence on the development of RFAAs could be detected.

Aged↗
PubMed1988

A 24 hour plastic envelope method for isolating and identifying Gardnerella vaginalis (PEM-GVA)

A new plastic envelope culture test that is selective for Gardnerella vaginalis was compared with a conventional method. Vaginal specimens from 92 women were cultured. Results from both methods were compared with the results of pelvic examinations and clinic screening tests used to diagnose bacterial vaginosis (BV). G vaginalis was isolated more often in the envelope than by the conventional method from patients with BV and those without, though the difference was not significant. Isolation and identification of G vaginalis was completed in 18-24 hours by the envelope method; the conventional method took a mean of 72 hours (range two to six days). Polymorphonuclear leucocytes (PMNLs) occurred significantly more in specimens from the patients without BV than from those with BV. Both clue cells and a positive amine test reaction were found significantly more in specimens from patients with BV than from those without BV. Clue cells and G vaginalis isolation correlated best with BV (in 47 women), followed by clue cells and positive amine test results (in 39). Adherence of G vaginalis in the envelope also correlated more with BV, clue cells, and positive amine test results (32) than with patients without BV (14). When there were no clue cells and amine test results were negative the results correlated totally with a prediction of no BV. The use of the rapid envelope culture test would have confirmed BV in 20% of the cases where clue cell and amine test results were discordant.

Bacteriological Techniques↗
PubMed1988

Surgical treatment of carotid paragangliomas presenting unusual technical difficulties. The value of preoperative embolization.

Although the application of reconstructive vascular surgical procedures to the treatment of carotid paragangliomas has made their resection the method of choice and has produced excellent cure rates, it has not obviated some of the technical problems presented by excessively vascular, adherent, or bulky lesions. Our experience with preoperative trans-catheter embolization for the reduction of the vascularity in six cases of this group of lesions is presented and the conclusion is made that preoperative embolization greatly reduced operative technical difficulties.

Adult↗
PubMed1987

Haemolysis affects insulin but not C-peptide immunoassay.

Venous blood was taken at the end of a glucose infusion test in 19 individuals and divided into four aliquots, 3 of which were variably haemolysed by repeated passage through a 23-gauge needle to simulate traumatic venepuncture. Plasma insulin (measured by both a charcoal separation and a double-antibody method), C-peptide, and haemoglobin were measured in each aliquot, and haemolysis was also assessed visibly. A significant loss of immuno-assayable plasma insulin was found in samples with only a trace of visible haemolysis, with up to 90% lost in severely haemolysed samples. Plasma C-peptide was unaffected by haemolysis. This represents an additional advantage for the use of plasma C-peptide in assessing insulin secretion.

C-Peptide↗
PubMed1987

Altered water excretion in healthy elderly men.

The renal and vasopressin (AVP) response to a standard oral water load (20 ml/kg) was examined in a group of water-replete healthy elderly men (n = 6). Two groups, respectively, of water-replete and water-deprived young healthy volunteers acted as controls. After 2 h, the old group had excreted 41 +/- 2.4% (mean +/- SEM) of the water load compared to 100.7 +/- 8.8% in the water-replete young group and 70 +/- 3.8% in the water-deprived young group (P less than 0.01). Similarly, peak diuresis (7.01 +/- 0.48 ml/kg) and peak free-water clearance (5.7 +/- 0.48 ml/min) as determined from hourly sampling in the old group were delayed and significantly less than both young groups (P less than 0.01) (peak diuresis, young water-replete, 10.86 +/- 0.56 ml/kg, young water-deprived, 10.2 +/- 0.64 ml/kg, peak free-water clearance, young water-replete 8.4 +/- 0.72 ml/min, young water-deprived 9.5 +/- 0.88 ml/min). When these indices were adjusted for reduced creatinine clearance (Ccr) in the elderly, there was no significant difference between the young and old groups. Plasma AVP decreased similarly in all three groups following ingestion of water but there was no significant difference in mean plasma AVP between the young and old subjects throughout the study period. We therefore conclude that ability to excrete excess water promptly is impaired in healthy elderly men. This defect is due, at least in part, to an age-related reduction in glomerular filtration rate.

Adult↗
PubMed1987

Erythrocyte aldehyde dehydrogenase, plasma chlorpropamide concentrations and the chlorpropamide alcohol flush.

Erythrocyte aldehyde dehydrogenase activity (EALDH) was measured in 21 diabetics on long-term chlorpropamide therapy. Median EALDH was 0.362 units, range 0.108 to 0.750 units and correlated neither with previously assessed chlorpropamide alcohol flushing nor with coincident plasma or erythrocyte chlorpropamide concentration. The hypothesis that genetic or permanently acquired reduction in EALDH correlates with CPAF status was not supported. There was no concentration-related inhibition of the enzyme by prevailing plasma or erythrocyte chlorpropamide.

Alcohol Drinking↗
PubMed1986

New aspects on the chemistry of tea and coffee. III.

The previous review for 1983/1984 is now continued with references to recent publications (1984/1985) and as before covers the chemistry and technology of tea (leaf, green and black) and coffee (raw, roasted and instant soluble), with particular reference to composition and changes during manufacture, extraction and storage. The effects of composition on the quality of the beverage, with mention of particular physiological properties, are included (210 references).

Chemical Phenomena↗
PubMed1986

A thirty-year survey of the reconstructive surgical treatment of aortoiliac occlusive disease.

With the view of assessing functional durability and the factors that influence or determine it, we reviewed the clinical course of 1748 reconstructive operations performed between Jan. 1, 1954, and Dec. 31, 1983 in the treatment of 1647 patients with aortoiliac occlusive disease (AIOD). Disabling intermittent claudication (in 65.6%), ischemic rest pain and/ or pregangrene (in 20.7%), and ischemic gangrene (in 13.7%) were the operative indications. Patency proven by angiography was the criterion of success. Follow-up was continuous and endless and 94% successful over a period of 30 years. Twenty-five percent of the patients were followed up for 11 to 30 years. The incidence of severe degree of occlusive involvement increased significantly from the first (9.3%) to the third (17.1%) decade of observation, whereas the perioperative mortality rate improved markedly from the first (7.4%) to the third (2.5%) decade. The aortobifemoral bypass (AF2B) procedure remained the most popular type of repair (with a perioperative patency rate of 91.4%) throughout, but both it and unilateral reconstructions lost some ground to remote (extra-anatomic) bypasses in the third decade. Atherosclerotic heart disease remained the most common cause of perioperative (50%) and late (60.2%) death. Among the early postoperative local complications graft thrombosis improved markedly from the first (8.3%) to the third (3.2%) decade. Graft infection remained rare (1.6% to 0.8%). The incidence of the most common late wound complication, anastomotic aneurysm at the common femoral level, remained relatively constant (5.7% per anastomosis), but it responded very well to surgical correction. The partial or complete secondary repair of all late complications (26.0%) improved the cumulative late patency rate in the AF2B procedures by 2% to 12% during 20 years of observation. The perioperative (97.3%), 5-year (76.6%), 10-year (76.6%), 15-year (72.5%), and 20-year (67.5%) cumulative patency rates of AF2B operations were highly satisfactory. The postoperative late survival rate of patients with AIOD declined rapidly (59% at 5, 33% at 10, 14% at 15 years). The cause of late death in 60.2% of the cases was atherosclerotic heart disease.

Aortic Diseases↗
PubMed1986

Indications for different modes of surgical therapy in medically refractory ventricular arrhythmias.

Fifty-one adult patients were referred for surgical treatment during the time period from July 1980 to November 1985. The average age was 59 +/- 6 years (19-70 years). All patients had symptomatic ventricular tachycardia that was refractory to standard or experimental drug therapy. On the basis of patient condition, site of arrhythmia, ventricular function, and extent of coronary disease, 21 patients were classed as good risk (GR) while 30 patients were thought to represent a poor surgical risk (PR). Thirty-two patients (15 GR, 17 PR) underwent electrophysiologic guided endocardial resection of arrhythmic foci. The hospital mortality was 12% (4/32), and two additional patients died late. All deaths were in poor risk patients. Recurrent arrhythmia was the primary cause of death in only one patient. Nineteen patients have required automatic internal cardioverter defibrillation (AICD) or chronic burst pacing (BP) with an implantable radiofrequency stimulator, with no operative mortality. AICD implantation was chosen for 13 drug refractory patients who were either poor surgical risk and/or had a tachycardia rate above 130 beats/minute with multiple scars or a multifocal tachycardia. Six additional patients who had tachycardia less than 130 beats/minute and whose arrhythmia could be safely terminated with BP had radiofrequency stimulator implantation. The one late death in this group was in a medically noncompliant patient. On the basis of this experience, we feel that map-guided endocardial resection should be offered to all good risk patients with a single scar and unifocal tachycardia who are refractory to medical treatment. This operation should be considered in all patients who have frequent, life-threatening attacks of tachycardia of any sort on maximum drug therapy. The remainder can be well managed with an AICD if their tachycardia rate is greater than 130 beats/minute or with BP using a radiofrequency stimulator.

Adult↗