Job and life satisfaction among rural physicians. Results of a survey

Results of a survey of approximately half of Minnesota's rural physicians show that these physicians appear to be well-satisfied with their jobs (average rating of 2.5 on a five-point scale with 2 = very satisfied and 3 = moderately satisfied). In aggregate, areas of greatest job satisfaction are the diversity of patients physicians see, physicians' contact with others, and their ability to derive personal gratification from patient care. Salary/income was not a source of dissatisfaction. Areas of least satisfaction are physicians' opportunities for promotion, their ability to remain knowledgeable, and their role in making organizational and administrative decisions. Rural Minnesota physicians feel least work stress about their feelings of clinical competence/interpersonal relations at work and anxieties about the future. Areas of greatest stress focus on time pressures and realities of medical practice, i.e., being reimbursed by third-party payers and meeting the need for certainty when medical knowledge only allows for approximation. These physicians are reasonably happy with their lives in general (5.4 on a seven-point scale with 7 = delighted, 1 = terrible). In aggregate, areas of lowest life satisfaction are physicians' social relations, leisure activities, and finances. Examination of subgroups shows that women are statistically less satisfied with their living situations; younger physicians are less satisfied with their work, their living situations, and their leisure activities; physicians who spend more than 10 hours per week on administrative duties are less satisfied with their living and social situations; and physicians who see more than 100 patients per week are less satisfied with their social relations.

Acute mitral regurgitation secondary to blunt chest trauma: report of a case

A 24-year-old male patient who sustained blunt trauma to the chest resulting in a flail chest, myocardial contusion and injury to mitral valve is reported. An emergency surgical correction of the mitral lesion was performed. A high index of suspicion, prompt diagnosis and aggressive intervention of such injuries can lead to successful repair of such a potentially fatal cardiac trauma.

Muscle glycogen storage postexercise: effect of mode of carbohydrate administration

The primary purpose of this study was to determine whether gastric emptying limits the rate of muscle glycogen storage during the initial 4 h after exercise when a carbohydrate supplement is provided. A secondary purpose was to determine whether liquid (L) and solid (S) carbohydrate (CHO) feedings result in different rates of muscle glycogen storage after exercise. Eight subjects cycled for 2 h on three separate occasions to deplete their muscle glycogen stores. After each exercise bout they received 3 g CHO/kg body wt in L (50% glucose polymer) or S (rice/banana cake) form or by intravenous infusion (I; 20% sterile glucose). The L and S supplements were divided into two equal doses and administered immediately after and 120 min after exercise, whereas the I supplement was administered continuously during the first 235 min of the 240-min recovery period. Blood samples were drawn from an antecubital vein before exercise, during exercise, and throughout recovery. Muscle biopsies were taken from the vastus lateralis immediately after and 120 and 240 min after exercise. Blood glucose and insulin declined during exercise and increased significantly above preexercise levels during recovery in all treatments. The increase in blood glucose during the I treatment, however, was three times greater than during the L or S treatments. The average insulin response of the L treatment (61.7 +/- 4.9 microU/ml) was significantly greater than that of the S treatment (47.5 +/- 4.2 microU/ml) but not that of the I (55.3 +/- 4.5 microU/ml) treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Quasi-static electric-field-enhanced degenerate four-wave mixing in a nematic liquid-crystal film

Degenerate four-wave mixing can be induced or enhanced dramatically when two weak overlapping laser beams are incident upon a nematic liquid-crystal film that is biased by a quasi-static electric field. This phenomenon is shown to be the result of the critical behavior at the Freedericksz transition. The experimental results show that the diffracted intensity is proportional to the third power of the laser intensity, as expected for a four-wave mixing process, despite the strength of the electric-field bias voltage above threshold.

Use of a total wash-out method in an open heart operation

Pathological cold agglutinins may induce hemolysis in patients who need hypothermic cardiopulmonary bypass and blood transfusion. A simple technique, termed the total wash-out method, was used in a patient with high thermal amplitude, moderate-titer cold agglutinin before hypothermic cardiopulmonary bypass. The patient's cold agglutinin titer decreased abruptly after operation. None of the preoperative hemolysis phenomena were found during her 6 months of follow-up.

Insensitivity of tensile failure properties of human bridging veins to strain rate: implications in biomechanics of subdural hematoma

The effects of strain rate on tensile failure properties of human parasagittal bridging veins were studied in eight unembalmed cadavers. While bathed in physiological saline at 37 degrees C, the intact vessel was stretched axially by a servo-controlled hydraulic testing machine at either a low strain rate of 0.1-2.5 s-1 or a high rate of 100-250 s-1. The mean ultimate stretch ratios for low and high strain rates, respectively, were 1.51 +/- 0.24 (S.D. n = 29) and 1.55 +/- 0.15 (n = 34), and the ultimate stresses were 3.24 +/- 1.65 (n = 17) and 3.42 +/- 1.38 MPa (n = 20). Neither difference between strain rates was significant (p greater than 0.45). Thus, our results do not support the hypothesis that sensitivity of the ultimate strain of bridging veins to strain rate explains the acceleration tolerance data for subdural hematoma in primates [Gennarelli, R. A. and Thibault, L. E. (1982) Biomechanics of acute subdural hematoma. J. Trauma 22, 680-686].

Muscle glycogen storage after different amounts of carbohydrate ingestion

The purpose of this study was to determine whether the rate of muscle glycogen storage could be enhanced during the initial 4-h period postexercise by substantially increasing the amount of the carbohydrate consumed. Eight subjects cycled for 2 h on three separate occasions to deplete their muscle glycogen stores. Immediately and 2 h after exercise they consumed either 0 (P), 1.5 (L), or 3.0 g glucose/kg body wt (H) from a 50% glucose polymer solution. Blood samples were drawn from an antecubital vein before exercise, during exercise, and throughout recovery. Muscle biopsies were taken from the vastus lateralis immediately, 2 h, and 4 h after exercise. Blood glucose and insulin declined significantly during exercise in each of the three treatments. They remained below the preexercise concentrations during recovery in the P treatment but increased significantly above the preexercise concentrations during the L and H treatments. By the end of the 4 h-recovery period, blood glucose and insulin were still significantly above the preexercise concentrations in both treatments. Muscle glycogen storage was significantly increased above the basal rate (P, 0.5 mumol.g wet wt-1.h-1) after ingestion of either glucose polymer supplement. The rates of muscle glycogen storage, however, were not different between the L and H treatments during the first 2 h (L, 5.2 +/- 0.9 vs. H, 5.8 +/- 0.7 mumol.g wet wt-1.h-1) or the second 2 h of recovery (L, 4.0 +/- 0.9 vs. H, 4.5 +/- 0.6 mumol.g wet wt-1. h-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Computerized quality control of radioimmunoassay in Korea

Automated data processing and quality control of radioimmunoassays offer not only increased speed but also a more thorough and statistically rigorous analysis of results. An external quality assessment scheme for serum thyroxine, triiodothyronine and thyroid stimulating hormone (TSH) assays was performed in five nuclear medicine laboratories in Korea to compare with the assay performances of the World Health Organization Radioimmunoassay Program. The required radioimmunoassay kits were supplied through the International Atomic Energy Agency (IAEA). We have determined the weighted root mean squared error, and variance ratio as the indices of standard curve and also the average batch coefficient of variation (ABCV) as the parameters of response error relationship curve and precision profile. There was a good fit for the triiodothyronine assay, but 3 of 5 laboratories showed possible bad fit in the T4 and TSH assay systems. The ABCV was less than 5 percent for the T3 and T4 assay system, however for the TSH system, only 1 laboratory showed the ABCV value of less than 5 percent. We have also calculated the within batch variation (drift) and between laboratory variations.

Duration of occupancy of opiate receptors by naltrexone

To determine the duration of blockade of mu-opiate receptors by naltrexone, we measured the binding of [11C]carfentanil in the brain of five normal volunteers with a positron radiation detection system before and 1, 48, 72, 120, and 168 hr after naltrexone administration. The half-time of blockade by naltrexone in the brain ranged from 72 to 108 hr which is greater than the fast plasma clearance components (4-12 hr) of naltrexone or its metabolite, beta-naltrexol, but corresponds well to the half-time of the terminal phase of plasma naltrexone clearance (96 hr). These results are consistent with the duration of the pharmacologic effects of naltrexone in response to heroin administration and indicate that 50 mg/day of oral naltrexone results in plasma levels in excess of that needed to saturate opiate receptors. This is the first example of the use of a simple dual-detector system with positron-emitting radioactive drugs to provide information regarding the duration of action of the drug on its specific receptor site. The plasma clearance half-time of a drug may not give an accurate reflection of the duration of action of the drug on a specific neuroreceptor site. Direct measurement of drug effects on recognition sites greatly extend current studies of pharmacokinetics.

Supplemental insulin delivery from an implanted reservoir activated by external compression

An implant made of insulin in palmitic acid provides a basal dose sufficient to reduce hyperglycemia for 42 +/- 12 days in rats with induced diabetes. For preprandial dose supplements another arrangement is required. In this study a device consisting of a reservoir is assembled by attaching a 1 cm diameter foam ring to a 5 mm diameter piece of the same material. A 6 mg piece of compressed insulin is inserted into a cut between the ring and the attachment, along with 2 mg tetracycline to hinder microbial growth. The assembly is then enclosed between two membranes and an annular external wall. The top membrane is pierced once, and the device is tested by implantation under the abdominal skin of diabetic rats. Serous fluid will enter the interior through the orifice and leach the solid insulin that does not leak out. Daily sidewise compression over the skinfold of the unanesthetized animal indicated that the insulin supply lasted for 24 +/- 4 days. The blood glucose was consistently maintained at 3.4 +/- 1.1 mmol/L for 6-8 hr each day. After depletion the device can be refilled percutaneously by injecting insulin suspended in phosphate-buffered saline.

Surgical treatment of supracristal type of ventricular septal defect

Surgically treated ventricular septal defect (VSD) was of supracristal type in 120 of 389 Chinese patients; 93 of the 120 were younger than 15 years. Concomitant aortic anomalies were present in 58 of the patients (regurgitation in 23 and cusp prolapse in 35). Corresponding figures among the 93 patients of the under-15 group were 40 (9 + 31). Direct suture or patch closure of the supracristal VSD and replacement or plication of anomalous aortic valves were the methods used. The results of direct closure were equal to those of patch closure. One patient died of subacute bacterial endocarditis, which had been present preoperatively. There were no other deaths. The postoperative observation period was 6 months to 7 years. As the incidence of associated valvulopathy increases with patient age, early operation for supracristal VSD, regardless of shunt volume, is advocated.

Biaxial mechanical properties of human pericardium and canine comparisons

The two-dimensional mechanical properties of human pericardium from seven males undergoing coronary artery bypass surgery were studied. A 25-mm square piece of parietal pericardium overlying the right ventricle was excised. An approximately 8-mm square target was marked at the center, and its dimension was measured electrooptically. When immersed in physiological saline at 37 degrees C, the specimen was subjected to biaxial isotropic loading. Large deformations developed in the beginning of the loading; the pericardium became increasingly stiffer when load was increased, and then became almost inextensible. As in canine pericardium [Lee et al., Am. J. Physiol. 249 (Heart Circ. Physiol. 18): H222-H230, 1985], hysteresis was present and tension-stretch relationship was insensitive to loading frequency during cyclic loading, relaxation of tension was substantial, and creep was insignificant. Unlike canine specimens, however, human pericardium was nearly isotropic and almost three times as thick [mean 0.55 +/- 0.02 mm (SD)]. The human tension-area relation for isotropic loading could be described by an exponential function and was found to shift significantly to the left of the canine. Therefore, human pericardium is less extensible than canine.

Lectins as markers for eosinophilic leukocytes

Lectin from Griffonia simplicifolia (GSA-I) and soybean (SBA) are reliable markers for human eosinophils. In this study we have shown that fluorochrome labeled GSA-I and SBA can be used for specific labeling of eosinophils in paraffin embedded tissue sections, in peripheral blood smears and in cell suspensions prepared for flow cytometry. These two lectins are useful diagnostic reagents which could be applied for further characterization of cytoplasmic components selectively found in human eosinophils.

A simple instrument for biochemical studies of the living human brain

A simple, relatively inexpensive radiation detection system was developed for measurement of positron-emitting receptor-binding drugs in the human brain. This high-efficiency coincidence counting system requires that only a few hundred microcuries of labeled drug be administered to the subject, thereby allowing for multiple studies without an excessive radiation dose. Measurement of the binding of [11C]-carfentanil, a high-affinity synthetic opiate, to opiate receptors in the presence and in the absence of a competitive opiate antagonist exemplifies the use of this system for estimating different degrees of receptor binding of drugs in the human brain. The instrument has also been used for measurement of the transport into the brain of other positron-emitting radiotracers, such as large neutral amino acids.

Lectin binding sites on human endocervix: a comparison with secretory and proliferative endometrium

Endocervix and corresponding endometrium of women of reproductive age were studied histochemically with 13 fluorescein isothiocyanate-labeled lectins to delineate the differences between the epithelial cells in two anatomical sites. Lectin from Maclura pomifera (MPA), Ulex europaeus (UEA-I), Glycine max (SBA), and Vicia villosa (VVA) bound only to endocervical epithelium and were the only four lectins that distinguished endocervical from endometrial epithelium. These differences were independent of menstrual cyclic changes and blood group antigen secretion. These data show that lectins can be used to histochemically distinguish endocervical from endometrial glands.

Blood flows in the maxillocarotid anastomoses and internal carotid artery of conscious dogs

Although the external carotid artery is known to contribute to the cerebral blood flow in anesthetized dogs, quantitative information on the anastomoses and their role in conscious dogs is lacking. This study was carried out to determine blood flows in these anastomoses and the internal carotid artery, and also to examine the functional significance of the anastomoses in conscious dogs. Fifteen-micron radioactive microspheres were injected into common and external carotid arteries of four conscious dogs through chronically implanted catheters. Blood flows were determined by the reference sample method and by comparing microsphere distributions in the brain and the masseter muscle. Blood flows were estimated to be 140 +/- 32, 7.7 +/- 1.4, and 3.3 +/- 1.1 ml/minute (mean +/- SD) in the common carotid artery, internal carotid artery, and anastomoses on each side, respectively. Additional evidence indicated that the anastomotic flow so determined was primarily the flow in the anastomotic artery. Humoral responses to angiotensin II infusions were also studied in conscious dogs. External carotid angiotensin increased plasma 11-hydroxycorticosteroid concentration (used as an index of ACTH secretion) but did not increase plasma vasopressin concentration to the same extent as common carotid infusion. Therefore, the external carotid artery is functionally important in perfusing the brain in conscious dogs.

Simplified detection system for neuroreceptor studies in the human brain

A simple, inexpensive dual-detector system has been developed for measurement of positronemitting receptor-binding drugs in the human brain. This high efficiency coincidence counting system requires that only a few hundred microcuries of labeled drug be administered to the subject, thereby allowing for multiple studies without an excessive radiation dose. Measurement of the binding of [11C]carfentanil, a high affinity synthetic opiate, to opiate receptors in the presence and in the absence of a competitive opiate antagonist indicates the potential utility of this system for estimating different degrees of receptor occupation in the human brain.

Regulation of the yeast metallothionein gene

To study regulation of the yeast CUP1 gene, we have employed plasmids containing the CUP1 regulatory sequences fused to the Escherichia coli galK gene. A comparison of galK expression from low- and high-copy-number CUP1/galK fusion plasmids demonstrated that both basal and induced levels of galactokinase (GalK) increase proportionately with plasmid copy number. Host strains with an amplified, single or deleted CUP1 locus were compared to look for effects of chromosomal CUP1 gene dosage on expression from the episomal CUP1 promoter. Basal GalK levels are similar in CUP1R and cupls hosts, but can be induced to higher levels in the cup1s than the CUP1R host. In contrast, in a strain deleted for the chromosomal copy of CUP1, synthesis of GalK is constitutive but can be induced to yet higher levels by copper. A hybrid vector, placing the CUP1 coding sequence under the control of a constitutive promoter, was constructed. Introduction of this hybrid CUP1 gene into the deletion host containing the CUP1/galK plasmid restores regulation. Thus, metallothionein, in trans, can effect repression of the CUP1 promoter. The possible roles of metallothionein and free copper in CUP1 regulation are discussed.

A constitutive model for two-dimensional soft tissues and its application to experimental data

A constitutive relation proposed by Shoemaker (Ph.D. dissertation, 1984) to model the mechanical behavior of membraneous or two-dimensional soft tissues is described. Experiments by Schneider (Ph.D. dissertation, 1982) on human skin and Lee et al. (Am. J. Physiol., 249, H222-H230, 1985) on canine pericardium, and the application of the constitutive model to biaxial stress-strain data from these experiments, are discussed. Some experimental data and predictions of the model obtained by curvefitting are presented for comparison. Values of material parameters are also presented. It is concluded that the constitutive model is well able to fit results of individual tests, and that its generality (judged by consistency of parameters from test to test of the same specimen), though not complete, does compare favorably with some other results presented in the literature.