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Biomedical subjects

R Madsen

Publications and source records attributed to R Madsen.

At least 37 records · Page 2Linked to original sources
PubMed1992

Modified nucleosides in human serum.

Methylated purines and pyrimidines derived from the degradation of transfer ribonucleic acid have been shown to be excreted in abnormal amounts in the urine of patients with cancer. Recent technology developed by Gehrke and Kuo has allowed the separation and quantification of modified nucleosides in serum using reversed-phase high-performance liquid chromatography with diode-array measurement. Serum levels of ten modified nucleosides were measured in 37 normal healthy adults to establish normal values and to correlate activity with age and sex. In addition, serum levels of patients with several malignancies were measured to determine activity in these diseases. Levels of modified nucleosides in normal individuals were consistently reproducible and showed no significant variation among males versus females or with age. Patients with malignant diseases showed consistent elevations and these were highest in patients with more advanced disease. The evidence of no significant differences in the mean levels of modified nucleosides in serum with age or sex in normal adults and elevations in patients with malignancies demonstrate the potential value of modified nucleosides as cancer biomarkers.

Adult↗
PubMed1992

Osmotic blood-brain barrier disruption and chemotherapy in the treatment of high grade malignant glioma: patient series and literature review.

In the past, chemotherapeutic treatment of patients with high grade malignant gliomas following surgery and radiation has not added significantly to the 12-14 month median survival rate. Over four years, 37 patients with high grade malignant gliomas underwent 246 treatment procedures with a combination of methotrexate, cyclophosphamide, and procarbazine given in association with hyperosmolar mannitol-induced transient breakdown of the blood-brain barrier. These patients have demonstrated a median survivorship of 22 months after considering age, Karnofsky Performance Score, and necrosis by the Cox Proportional Hazards model. The study group had a mean age of 43 years, and mean Karnofsky Performance Score of 67%. Sixty-five percent of the procedures had well-documented barrier disruption. Sixteen percent remained in complete remission while 24 patients (65%) had partial or temporary remission. Progression-free intervals after blood-brain barrier disruption/chemotherapy ranged from 1-47 (mean 15) months. Neurotoxicity has been minimal with one peri-procedural mortality and five patients suffering an increase in neurologic deficit after a procedure. The results of this study are consistent with and further extend the reported literature on this method of brain tumor therapy as described in other centers. Chemotherapy in conjunction with osmotic disruption of the blood-brain barrier may provide the pharmacokinetic advantage sufficient to significantly improve survival in patients with high grade malignant glioma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1991

Impact of unstable angina on operative mortality with coronary revascularization at varying time intervals after myocardial infarction.

We have performed a retrospective study of patients undergoing coronary artery bypass grafting for postinfarction angina in an effort to determine the influence of recency of myocardial infarction and unstable angina on operative mortality. Time from myocardial infarction to bypass was arbitrarily divided into five intervals. Nine hundred ninety-three patients having isolated coronary bypass for postinfarction angina were analyzed, and a significant trend of increased operative mortality with recency of myocardial infarction was found (p less than 0.001). When patients were operated on during the time interval zero to 24 hours after infarction, the operative mortality rate was 18.6%. In the interval from 1 day to 1 week after infarction, the operative mortality rate was 7.4%; 1 week to 3 weeks, 5.9%; and 3 weeks to 3 months, 2.7%. In patients operated on more than 3 months after infarction, the operative mortality rate was 3.9%. The operative mortality rate in 360 patients with postinfarction stable angina was 0.83% compared with 7.3% in 633 patients with postinfarction unstable angina (p less than 0.001). Of 18 risk factors tested, 12 were found by univariate analysis to be independent predictors of operative mortality, including recency of myocardial infarction and unstable angina. Stepwise logistic regression analysis of independent predictive variables revealed that unstable angina, previous surgical revascularization, preoperative hypotension, nonelective surgery, preoperative cardiac arrest, and female sex were the strongest predictors of mortality; recency of myocardial infarction was not a factor. When acute surgical reperfusion is not the primary treatment strategy for patients with myocardial infarction, operative mortality with coronary bypass is increased with the recency of myocardial infarction. The reason for this increase in operative mortality is a patient selection process in which those with persistent or intermittent myocardial ischemia, as reflected in the clinical syndrome of unstable angina, are selected for operation. Unstable angina is a major determinant of operative mortality after myocardial infarction. In patients with stable angina, operative mortality is not increased by the recency of myocardial infarction.

Adult↗
PubMed1990

Suppression of motor evoked potentials by inhalation anesthetics.

The purpose of this study was to record evoked action potentials from forearm muscles in response to single-shock supramaximal electrical stimulation of motor cortex in room air and under different concentrations (0.5-1.5%) of isoflurane, enflurane, and halothane anesthesia in rats. Anesthesia was induced with a mixture of fentanyl and droperiodol, which was then followed by 10-min inhalation of each gas anesthetic under controlled ventilation. Increasing concentrations of isoflurane (n = 12) caused a progressive increase in onset latency and a decrease in peak-to-peak amplitude and duration. Similar increases in latency and decreases in amplitude and duration occurred under enflurane (n = 10) and halothane (n = 10) anesthesia. The three anesthetics caused a significant latency increase over baseline (room air) values for concentrations from 0.5 to 1.5% (p < 0.01). The amplitude and duration of muscle responses under all three volatile anesthetics at 0.5-1.5% concentrations were significantly lower than baseline (p < 0.01). Isoflurane, enflurane, and halothane anesthesia significantly altered the muscle response evoked by motor cortex stimulation in experimental animals.

Journal Article↗
PubMed1989

Bone marrow involvement in small cell lung cancer. Clinical significance and correlation with routine laboratory variables.

Of 129 patients with small cell lung cancer (SCLC) who underwent bone marrow examination for staging, 39 (30%) had bone marrow involvement. Only three of 129 patients (2.3%) had bone marrow involvement as the only site of metastatic disease. When patients with bone marrow metastasis were compared with patients whose bone marrow was normal, there were significant differences in serum levels of lactate dehydrogenase (LDH), glutamic oxalacetic transaminase (SGOT), glutamic pyruvic transaminase (SGPT), alkaline phosphatase (AP), albumin, and sodium (Na). We found no clinically significant difference in survival between patients with extensive disease with or without bone marrow involvement. Serum Na, albumin, SGOT, and uric acid were important prognostic determinants of survival. Based on the results of this study, we do not recommend routine bone marrow examinations in the staging of SCLC.

Adult↗
PubMed1989

Elevated hemidiaphragm after cardiac operations: incidence, prognosis, and relationship to the use of topical ice slush.

We have reviewed chest roentgenograms of 745 patients before hospital dismissal after cardiac operations and serially to determine the incidence and prognosis of elevated hemidiaphragm and any relationship to the use of topical ice slush (TIS) in myocardial preservation. All patients had similar myocardial preservation techniques including moderate systemic hypothermia and 4 degrees C saline solution poured over the heart at aortic clamping. During a 12-month period, TIS was added to the saline bath. Two (2.4%) of 84 patients before TIS and 5 (2.5%) of 201 consecutive patients operated on since discontinuing TIS had elevated hemidiaphragm on the predismissal roentgenogram. Of 460 patients in whom TIS was employed, 109 (23.7%) had elevated hemidiaphragm (p less than 0.001). When TIS was employed, elevated hemidiaphragm developed in 72 (26%) of 280 patients without internal mammary artery takedown versus 13 of 33 patients (39.4%) with takedown of the internal mammary artery (p = 0.047). Ninety-nine patients with elevated hemidiaphragm were available for follow-up at 1 month, at which time 79 (79.8%) continued to have elevated diaphragm. At 1 year, 14 (21.9%) of 64 patients had persistent diaphragm elevation. We conclude that TIS predisposes to elevated diaphragm and that the incidence is increased when the internal mammary artery is harvested.

Coronary Artery Bypass↗
PubMed1989

Myelodysplastic syndrome: prospective evaluation of fifty-one patients using the Dutcher scoring system.

Fifty-one patients with primary myelodysplastic syndrome were prospectively evaluated using a scoring system based on the presentation blood and bone marrow findings. Twenty-four patients (47%) evolved to acute nonlymphocytic leukemia. Stepwise regression model showed that the scoring system was the only significant variable for predicting transformation to acute leukemia (p = 0.0007, sensitivity 70.8%, specificity 77.8%). Seventy-six percent of patients with a score of 14 or greater developed acute leukemia compared to 19% with a score of 13 or less. Median survival of the entire group was 10 months. The most important prognostic factor for predicting survival was the scoring system (p = 0.0001). Survival correlated inversely with the score. This scoring system may be useful in the management of patients with myelodysplasia.

Acute Disease↗
PubMed1989

[Maxillo-mandibular sagittal relations in the lateral facial examination].

For the purpose of developing a clinical method of facial examination that could permit a determination of the skeletal position of the upper jaw and the mandible, a sample of 70 teleradiographies of individuals among 8 and 18 years of both sexes was analyzed. The anteroposterior relationship of the maxila to the cranium was analyzed through perpendiculars from skin points Nasion, Glabela and Subnasal to the Frankfurt horizontal plane and it was found that Glabela was 2 mm behind Subnasal. The anteroposterior position of the mandible related to the maxila was studied on a perpendicular to Tragion-Subnasal plane descended from point Subnasal and it was found that the labiomental fold was coincident with this perpendicular. A new clinical method using a square rule leaned on the cheek using these reference points is recommended.

Adolescent↗
PubMed1978

Gastric bezoars. A technique of endoscopic removal.

Gastric bezoar formation is an uncommon sequela of gastroduodenal surgery or unusual eating habits. Because they generally produce severe symptoms, their removal is always necessary. Previously, this required surgical extirpation or slow enzymatic dissolution. We present here an endoscopic procedure for bezoar removal utilized successfully in five patients with vegetable-mucus bezoars. This technique employs a jet spray of water under direct vision to mechanically disrupt the bezoar, which may then be removed using a large gastric lavage tube. This procedure is simple, safe, and rapid and is therefore recommended as an alternative to surgical removal or enzymatic dissolution of gastric bezoars.

Bezoars↗
PubMedDate not supplied

Increased arterial stiffness in children with a parental history of hypertension.

The vascular dynamics of children with a parental history of hypertension has not been defined. The purpose of the current study was to determine whether or not these children have different arterial stiffness compared to the offspring of normotensive parents. One hundred healthy, nonobese subjects (ages 10-21 years) were divided into two groups of 50. Group A included the offspring of hypertensive patients and group B the offspring of normotensive parents. The variables studied were body surface area, blood pressure, and systolic and diastolic diameters of the aortic and carotid arteries as well as maximum velocity flow of these vessels. Carotid and aortic stiffness were calculated. Children and adolescents with a parental history of hypertension had higher carotid stiffness and smaller carotid diameters. These differences continued to be significant when correcting for body surface area. A higher blood pressure and a greater body surface area were also found.

Adolescent↗
PubMedDate not supplied

Gender, social networks and survival time: a 20-year study of the rural elderly.

The study design is a 20-year panel of 1700 rural elderly individuals who were interviewed in 1966, 1974 and in 1986-1987. The dependent variable was survival time. Proportional hazards and time dependent covariates were used to analyze the data. Gender differences in survival were explored. Participation in formal social networks predicted survival time. The findings support Durkheim's theory of social integration and call into question genetic differences as the explanation for the differential survival time of men and women.

Journal Article↗
PubMedDate not supplied

The effect of a rapid sequence induction protocol on intubation success rate in an air medical program.

The purpose of this study was to examine the percentage of successful intubations before and after implementation of a rapid sequence induction (RSI) protocol in patients treated by our flight nurses and paramedics. The records of 100 intubation attempts before the RSI protocol was implemented and 98 after implementation were reviewed. Success rate of intubation was 79% in the preRSI patient group and 84.7% in the postRSI group. No significant difference existed in the number of patients successfully intubated preRSI compared with postRSI. The statistically significant patient characteristics associated with unsuccessful intubation were facial trauma, combativeness, vomiting, and nasal bleeding.

Air Ambulances↗