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Biomedical subjects

R F Smith

Publications and source records attributed to R F Smith.

At least 145 records · Page 8Linked to original sources
PubMed1984

Central venous thrombosis and embolism associated with peritoneovenous shunts.

During a five-year period from Aug 1, 1977 through Aug 1, 1982, 36 patients required 47 peritoneovenous shunt procedures (36 initial and 11 revisions) for the management of their intractable ascites. The results at six months showed 23 (63.9%) of 36 patients were dead, but in those living, 12 (92.3%) of 13, the ascites was satisfactorily controlled. Patency was measurably prolonged by appropriate revision of the shunt. The early and late complication rates were surprisingly high, 38.3% and 40.4%, respectively. The most serious complication was central venous thrombosis, 11 (23.4%) of 47 procedures, including one nonfatal and two fatal pulmonary emboli. Treatment included the use of fibrinolytic agents, anticoagulation, and shunt revisions. Careful attention to the details of shunt fabrication, insertion, and patient selection may help to reduce the occurrence of central venous thrombosis associated with peritoneovenous shunts.

Adolescent↗
PubMed1984

New aspects on the chemistry of tea and coffee. A short review.

Recent publications (1982/1983) on the chemistry and technology of tea (leaf, green and black) and coffee (raw, roasted and instant), in particular with respect of their composition and changes during manufacture and storage, and the effects of composition on the quality of the beverages, are reviewed (101 references).

Chemical Phenomena↗
PubMed1984

Assay of microalbuminuria using gel electroimmunoassay.

The possibility of using electroimmunoassay as a technique for assessing microalbuminuria in the diabetic population has been studied. The method was found to be precise (given inter-batch coefficients of variation of 5.7% and 5.8% at levels of 16 mg/l and 23 mg/l respectively), showed adequate sensitivity, and produced results which correlated well (r = 0.971) with these obtained from a routine radioimmunoassay procedure. It is concluded that electroimmunoassay provides a reliable alternative to more sophisticated techniques in the non-specialized laboratory dealing with only moderate numbers of specimens.

Albuminuria↗
PubMed1984

Neonatal preference for visual patterns: modification by prenatal anesthetic exposure?

Exposure to anesthetic drugs during gestation has been shown to cause behavioral changes in rats, and exposure during labor and delivery also affects human neonatal behavior. In this preliminary study, nine neonates who had been exposed to anesthetic agents during gestation were tested for visual-pattern preference. These nine infants looked at the stimuli for statistically significantly longer periods compared with 30 non-exposed infants, and had significantly different preferences for some pairs of patterns. The results suggest that prenatal exposure to anesthetic agents may contribute to behavioral alterations in human neonates.

Adult↗
PubMed1984

Enzyme immunoassay for diagnosis of gonorrhea.

An enzyme immunoassay (EIA; Gonozyme [Abbott Laboratories]) for gonococcal antigen was assessed for the rapid diagnosis of gonorrhea. Patients attending two sexually transmitted disease clinics were tested by EIA and culture on Thayer-Martin medium. EIA was highly effective in detecting gonococcal infection among symptomatic men, with 70 of 75 (93.3%) culture-positive men having positive tests and no false-positive reactions. The performance of the test was not as good in detecting cervical gonorrhea; the best result obtained was a sensitivity of 87% (33 of 38) for EIA compared with culture. EIA false-positives occurred at a relatively low rate for women, with the test having a specificity of ca. 97%. The test clearly is capable of detecting gonococcal antigen in cervical and urethral specimens, but its role in routine diagnosis is not clear. Its performance seems equal to that of the Gram stain for men, but it seems to be less sensitive than culture for cervical gonorrhea--a drawback in high-risk populations. The low false-positive rate could be an important issue in screening low-prevalence populations.

Antigens, Bacterial↗
PubMed1984

Electrophysiological effects of high-dose propranolol in dogs: evidence in vivo for effects not mediated by the beta adrenoceptor.

Closed-chest dogs anesthetized with morphine and chloralose were studied to determine if direct or nonspecific cardiac electro-physiological effects of propranolol occur at clinically relevant plasma concentrations and to differentiate the nonspecific effects from those due to beta adrenoceptor blockade. In 19 dogs, ventricular monophasic action potential durations (MAP), ventricular effective refractory periods (VERP) and His bundle electrograms (A-H and H-V intervals) were measured at base line and during sequential infusions of isoproterenol, dl-propranolol and dl-propranolol plus an isoproterenol infusion designed to overcome beta blockade. A mean plasma propranolol level of 979 +/- 344 ng/ml produced a significant (P less than .05) prolongation of A-H (95 +/- 20-115 +/- 13 msec), MAP (179 +/- 26-194 +/- 14 msec) and VERP (159 +/- 12-177 +/- 13 msec). Infusion of the beta agonist, isoproterenol, returned A-H and MAP to values not significantly different from base line, whereas VERP remained prolonged at 174 +/- 11 msec (P less than .05). No significant changes occurred in a control group of 14 dogs infused with saline. In eight additional dogs, infusions of d- and dl-propranolol, given on separate days, were used to produce equal beta blockade determined by individual isoproterenol sensitivity tests. A-H, H-V, MAP and ventricular strength-interval curves (VRP) and diastolic thresholds (DT) were measured and treatment vs. base-line changes (delta) with d- and dl-propranolol were compared.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1983

Bilharzial portal hypertension.

Schistosomiasis is a major world health problem that is being encountered more frequently in North America as the immigration patterns from endemic areas change. At Henry Ford Hospital in Detroit, only two admissions for active schistosomiasis were recorded before 1970, but since then there have been 43 such cases. Of these 45 patients, six required seven portasystemic shunts, primarily to treat the complication of esophageal variceal hemorrhage, which is associated with portal hypertension secondary to presinusoidal hepatic fibrosis. No operative deaths occurred, and follow-up averaging 6.6 years revealed no late deaths and minimal encephalopathy. These excellent results are attributed to successful portal decompression and the well-preserved liver function that is typical of these patients. Bilharzial portal hypertension should be suspected in immigrants from endemic areas who have bleeding esophageal varices.

Africa↗
PubMed1983

Chlorpropamide-alcohol flushing and plasma chlorpropamide concentrations in diabetic patients on maintenance chlorpropamide therapy.

Forty-three diabetic patients on maintenance chlorpropamide (100-750 mg daily) drank 0.2 ml/kg 90% ethanol after equilibration in a room controlled at 20 degrees C. Twenty-five patients had already noted marked alcohol flushing since starting chlorpropamide therapy (group A), while 13 had not observed this (group B). The remainder were teetotal or unsure of their reaction. Cheek temperature rise correlated with plasma chlorpropamide concentration (r = 0.6, p less than 0.001) in all patients and was inversely related to basal cheek temperature (r = -0.35, p less than 0.02). Plasma chlorpropamide correlated with daily chlorpropamide dose (r = 0.8, p less than 0.001) but not with basal cheek temperature. The correlation between chlorpropamide level and cheek temperature rise was strengthened on analysis of group A alone (r = 0.7, p less than 0.001) and absent in group B (r = 0.2, p greater than 0.3) who tended to have lower chlorpropamide levels and cheek temperature rise than group A.

Body Temperature↗
PubMed1983

Electrophysiologic actions of high plasma concentrations of propranolol in human subjects.

The authors have previously shown that 40% of patients whose ventricular arrhythmias respond to propranolol require plasma concentrations in excess of those producing substantial beta-receptor blockade (greater than 150 ng/ml). However, the electrophysiologic actions of propranolol have only been examined in human beings after small intravenous doses achieving concentrations of less than 100 ng/ml. In this study, the electrophysiologic effects of a wider concentration range of propranolol was examined in nine patients. Using a series of loading and maintenance infusions, measurements were made at baseline, at low mean plasma propranolol concentrations (104 +/- 17 ng/ml) and at high concentrations (472 +/- 68 ng/ml). Significant (p less than 0.05) increases in AH interval and sinus cycle length were seen at low concentrations of propranolol, with no further prolongation at the high concentrations; these effects are typical of those produced by beta-blockade. However, progressive shortening of the endocardial monophasic action potential duration and QTc interval were seen over the entire concentration range tested (p less than 0.05). At high concentrations, there was significant (p less than 0.05) further shortening of both the QTc and monophasic action potential duration beyond that seen at low propranolol concentrations, along with a progressive increase in the ratio of the ventricular effective refractory period to monophasic action potential duration. No significant changes were seen in HV interval, QRS duration or ventricular effective refractory period. In summary, the concentration-response relations for atrioventricular conductivity and sinus node automaticity were flat above concentrations of 150 ng/ml.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1983

Increased cortisol excretion in chronic pain.

Urine samples were collected from 67 patients attending a Regional Pain Unit for treatment of chronic pain. Patients treated with steroids or with any signs or symptoms of Cushing's syndrome were excluded. The urine cortisol creatinine ratio was subsequently measured. Values for the urine cortisol/creatinine ratio were elevated in 31% of the patients, and grossly elevated in some. These patients could not be differentiated from those with normal ratios on the basis of pain or mood scores, cause of pain or drug therapy; they tended to have pain of shorter duration. Possible interpretations of these results are discussed.

Chronic Disease↗
PubMed1983

Viability of Trichomonas vaginalis in vitro at four temperatures.

The effect of temperature as a possible factor on the survival of Trichomonas vaginalis for shipment or routine laboratory maintenance was studied. Ten strains of T. vaginalis, ATCC 30001, ATCC 30238, and eight clinical isolates, were examined for viability when kept incubated at 37 degrees C or removed from this temperature and held at 42, 22, or 5 degrees C for increasing lengths of time without subculture or reincubation at 37 degrees C. The order in which the strains remained viable without subculture was: 5 degrees C, 8 to 10 days; 22 degrees C, 4 to 8 days; 37 degrees C, 4 to 6 days; 42 degrees C, less than 2 days. Vials of medium with cells were also held at 22 and 5 degrees C and then reincubated at 37 degrees C. Cultures held at 22 degrees C remained viable 6 to 8 days, whereas those stored at 5 degrees C remained viable 10 to 14 days. These data show that T. vaginalis withstands a wide range of temperatures, particularly below normal growth temperatures without subcultures, beyond what would be expected in mailing cultures.

Female↗
PubMed1983

Electrophysiologic actions of O-demethyl encainide: an active metabolite.

Differences between the electrophysiologic actions of the antiarrhythmic agent encainide have been reported after short-term intravenous and oral administration. Only prolongation of the HV interval and QRS duration have been described immediately after short-term intravenous administration of encainide in dogs and man. However, during oral therapy or more prolonged infusions, prolongation of the AH interval and atrial and ventricular effective refractory periods have also occurred. In most patients receiving encainide therapy, metabolites (O-demethyl encainide and 3-methoxy-O-demethyl encainide) accumulate during prolonged therapy to concentrations greater than those of the parent drug. We compared the electrophysiologic action of O-demethyl encainide with that of saline in anesthetized dogs to determine if this metabolite has pharmacologic activity and whether its electrophysiologic effects could account for the disparities noted between effects of intravenous and oral encainide therapy. An initial pharmacokinetic evaluation allowed design of a series of loading and maintenance infusions that produced plasma concentrations similar to those seen during encainide therapy in man (concentration after first maintenance dose, 149 +/- 27 ng/ml [+/- SE] and after second maintenance dose, 230 +/- 45 ng/ml). Significant increases in atrial effective refractory period and ventricular refractoriness, and prolongation of AH interval and HV conduction time were observed. These effects are similar to those reported after prolonged oral encainide therapy but are substantially different from those seen after short-term infusions of encainide. These findings indicate that the difference between the electrophysiologic actions of intravenous and oral encainide may be due to pharmacologic effects of at least one encainide metabolite, O-demethyl encainide.

Action Potentials↗
PubMed1983

Resuscitative thoracotomy for patients with traumatic injury.

The clinical course and final outcome were determined for 63 trauma victims who underwent resuscitative thoracotomy (RT) for hypovolemic cardiac arrest in the Department of Emergency Medicine during a 24-month period. The objectives of the study were to determine the efficacy of and indications for RT and to define the prognostic signs for survival. Of 63 patients, six were successfully resuscitated (9.5%), and five of these were discharged from the hospital (7.9%). The presence of pupillary reactions was an extremely reliable indicator of successful outcome (P = 0.0009), as was the presence of some respiratory effort (P = 0.025). None of the victims of blunt trauma (n = 6) or severe head injury (n = 13) survived. Three of 17 patients (17.6%) with stab wounds and two of 36 (5.6%) with gunshot wounds survived the procedure. RT was beneficial in 13.6% of patients who had isolated organ system injuries, but no patient with injuries to more than two organ systems survived. Victims of isolated penetrating thoracic trauma had an 11.8% survival rate, as opposed to a 0% survival rate for those with abdominal trauma. The best prognosis was in victims with penetrating cardiac injuries, who had a 22.7% survival rate. The cost of RT averaged $1660 per patient, exclusive of physician charges. In our experience, RT is most beneficial for victims of penetrating thoracic trauma, especially those with cardiac injuries. However, routine use of this high cost/low benefit procedure cannot be recommended for patients who have cardiac arrest secondary to blunt trauma or severe head injuries. Also, it is not recommended for patients whose pupillary reflexes and respiratory movements are absent.

Adolescent↗
PubMed1983

Fractures of the distal end of the femur below hip implants in elderly patients. Treatment with the Zickel supracondylar device.

Four elderly patients with a fracture of the distal end of the femur below a pre-existing non-cemented hip implant were treated with the Zickel supracondylar device using a closed intramedullary technique. The results were uniformly successful and there were no complications. This method is recommended if the fracture is not comminuted and the proximal implant does not so obstruct the femoral canal as to prevent the passage of the two intramedullary rods.

Aged↗