Showing papers by "University of Alabama published in 1975"

Regional Cerebral Blood Flow by 133Xenon Inhalation

Abstract: Repeated measurements of regional cerebral blood flow (rCBF) were made by the short (ten minutes) 133Xenon inhalation technique and bicompartmental analysis in 11 patients with cerebrovascular disorders, mainly acute cerebral infarction. rCBF was measured 3 to 11 times during one to two weeks. The blood flow of the fast compartment (f1) was calculated as well as the relative weight of this compartment (w1, assumed to correspond to gray matter). In addition a new flow index, the Initial Slope Index (ISI) modified for the inhalation technique, was used. This index of predominantly gray matter flow was calculated from a one-minute epoch of the early part of the clearance curve corrected for recirculation. In three of the patients the f1 and ISI varied in parallel and the w1 showed generally only minor variations from one measurement to the other. However, in the other eight patients fluctuation of the w1 and f1 values were seen which often showed no meaningful relation to the clinical course. The observed w1 changes indicated that some tissues (slowly perfused gray matter and/or rapidly perfused white extracerebral tissues) fluctuate between the fast and the slow compartment. In such cases the f1 values obtained cannot be used for comparison between measurements, since they represent flow rates of varying tissues and do not always represent a true gray matter blood flow. In these patients the ISI, which is independent of such weight changes, showed moderate and clinically likely variations.

Coronary anatomy and arteriography in patients with unstable angina pectoris.

Abstract: A prospective series of 188 patients with the syndrome of unstable angina pectoris undergoing coronary arteriography was reviewed to determine the spectrum of anatomic coronary artery disease, suitability for coronary revascularization and in-hospital morbidity and mortality. Thirty-two patients demonstrated normal to moderately diseased coronary arteries. None of these patients sustained myocardial infarction or died. Twenty patients (10.6 percent) had normal coronary arteriograms. Of the 156 patients having severe coronary artery disease (greater than 70 percent stenosis), 20 patients (13 percent) had left main coronary artery disease. One hundred forty-two patients (91 percent) were potential candidates for coronary surgery; 14 were not candidates because of distal vessel disease or poor left ventricular function. During cardiac angiography or in the subsequent hospital period 12 patients sustained a myocardial infarction and 7 of these died. Of these seven, six had left main coronary artery disease and one had three vessel disease. In three patients who died (1.9 percent of those with severe coronary artery disease) the death may have been related to cardiac catheterization because evidence of myocardial necrosis began within 24 hours of study. Thus, patients with the syndrome of unstable angina pectoris usually presented with severe coronary artery disease and were candidates for coronary revascularization. The anatomic severity of coronary artery disease appeared to be the most important factor contributing to myocardlal infarction or death after cardiac catheterization. Mortality after catheterization was primarily associated with left main coronary artery disease.

A survey of anesthetic health hazards among dentists

Abstract: All male members of the American Society of Oral Surgeons and a sample of the American Dental Association membership were surveyed for exposure to anesthetic gases and the incidences of certain health problems. Concentrations of waste inhalation anesthetic gases in the dental surgery are several times those found in hospital operating rooms. This study establishes a relationship between exposure to waste gases and the incidence of health problems including spontaneous abortion in spouses, congenital abnormalities in offspring, and cancer and liver disease. Measurable concentrations of waste anesthetic gases have been found in hospital dental operating rooms. A mail survey of 4,797 general dental practitioners and 2,642 oral surgeons indicated that 20.2% of the general practitioners and 74.8% of the oral surgeons had anesthetic exposures exceeding three hours per week. In the comparison of the health of individuals exposed or unexposed to inhalation anesthetics, there was a significant increase (78%) of spontaneous abortion in the spouses of exposed dentists and a significant increase (156%) in liver disease for exposed dentists. The implication of these findings and possible solutions are discussed.

P waves during ectopic atrial rhythms in man: a study utilizing atrial pacing with fixed electrodes.

Abstract: Threshold bipolar pacing was performed from one of 12 selected atrial sites with temporary implanted electrodes in 69 patients following open-heart surgery in order to study P wave polarity and morphology and the P-R interval during paced ectopic atrial rhythms. A negative P wave was recorded in lead I only with pacing the left atrium and only when pacing near the left pulmonary veins. A positive bifid P wave in V1 was recorded only with left atrial pacing and only when pacing was near the inferior pulmonary veins and coronary sinus. P wave polarity and morphology were otherwise of no use in localization of the origin of the impulse in these studies. The pacing stimulus to P wave interval was found to vary between 10 and 54 msec, making the duration of the P-R interval an unreliable indicator of the site of origin of the paced impulse. Although the relation of these paced rhythms to spontaneously occurring ectopic rhythms is unclear, the previously published criteria for localizing ectopic atrial rhythms are again demonstrated to be unreliable. P wave polarity and morphology and the P-R interval are of limited value in ascertaining the origin of ectopic atrial rhythms in man.

Effects of glucose-insulin-potassium on myocardial substrate availability and utilization in stable coronary artery disease. Studies on myocardial carbohydrate, lipid and oxygen arterial-coronary sinus differences in patients with coronary artery disease.

Abstract: To assess the metabolic effects of myocardial substrate alteration In patients with coronary artery disease, glucose-insulin-potassium solution was administered intravenously for 30 minutes to 14 men with stable angiographically documented coronary artery disease. The glucose-insulin-potassium solution (300 g of glucose, 50 units of regular insulin and 80 mEq of potassium chloride per liter of water) was infused at a constant rate in each patient, but individual infusion rates ranged from 0.013 to 0.032 ml/kg per min (4 to 10 mg glucose/kg per min) in the 14 patients. Simultaneous arterial and coronary sinus samples were obtained at 15 minute intervals during a stable 30 minute control period and again at 15 minute intervals during the infusion; samples were assayed for glucose, lactate, free fatty acid and oxygen content. In all 14 patients, during the glucose-insulin-potassium infusion, arterial glucose and lactate increased and arterial free fatty acid levels fell; the magnitude of the changes in arterial lactate and free fatty acids as related to the rate of infusion. Arterial-coronary sinus differences (A-C s ) for glucose, lactate and free fatty acid levels correlated with the arterial concentrations of these substrates ( r = 0.66, 0.87 and 0.79, respectively). Regression analyses demonstrated myocardial thresholds for the uptake of these substrates as follows: glucose 79 mg/100 ml; lactate 300 μmole/liter; and free fatty acids 100 to 200 μEq/liter. Finally and most importantly, the reduction in A-C s oxygen values after glucose-insulin-potassium infusion correlated with the reduction in A-C s free fatty acid levels ( r = 0.64, P Myocardial substrate availability may be an important determinant of myocardial oxygen demand in patients with coronary artery disease. Infusion of glucose-insulin-potassium solution has the potential to alter myocardial substrate availability, thus improving the balance between myocardial oxygen demand and supply.

Comparative electron-microscope studies on type-III and type-I collagens.

Abstract: Long-spacing-segment crystallites prepared from type III collagen with the chain composition [alpha1(III)]3 and type I collagen with the chain composition [alpha(I)]i12alpha2 have been compared in the electron microscope after positive. staining with phosphotungstic acid and uranyl acetate. The comparison revealed several differences in intensities of the cross-striation bands as well as significant differences in band positions. The latter occur most prominently in three distinct regions of the crystallites. Further, crystallites prepared from type III collagen contain an additional intensely staining band in an area corresponding to the carboxy-terminal end of the molecule. The latter band is still observed following limited pepsin digestion and presumably represents a slight elongation of the helical portion of the type III molecule when compared to the type I molecule. In spite of the somewhat altered distribution of charged groups as indicated in studies on the long-spacing-segment crystallites, type III molecules are capable of forming fibrils of the native type with a cross-striation pattern and periodicity virtually identical to that observed when type I molecules are precipitated as native fibers.

Intramyocardial pressure: Effect of preload on transmural distribution of systolic coronary blood flow

Abstract: Impairment of systolic coronary blood flow (CBF) may be mediated by intramyocardial pressure (PIM). However, the effect of systole on the magnitude and transmural distribution of coronary blood flow has not been investigated. The purpose of this study was to measure this effect, and, indirectly, intramyocardial pressure. It is assumed that intramyocardial pressure acts on the coronary vessels as a Starling resistor, such that local coronary blood flow is determined by the equation: Coronary perfusion pressure minus intramyocardial pressure equals resistance times coronary blood flow. This equation was integrated with respect to time and solved simultaneously for intramyocardial pressure and resistance by measuring regional coronary blood flow (radioactive microsphere technique) during maximal coronary vasodilatation in two states: beating and hypocalcemic diastolic arrest. Measurements were made in 7 to 16 concentric layers of the left ventricle of 16 dogs. Intramyocardial pressure ranged from near zero to twice peak left ventricular pressure. The transmural distribution of intramyocardial pressure and systolic coronary blood flow depended on preload. The transmural distribution of the ratio of intramyocardial pressure to coronary perfusion pressure was not significantly different from unity across the left ventricular wall at low levels of preload (0 to 4 mm Hg). At moderate to high levels of preload (7 to 35 mm Hg) this ratio was not different from unity (mean 1.03 and 0.96) in the two inner fifths of the left ventricular wall, but was significantly lower (mean 0.79, 0.64 and 0.41, respectively) in the middle and two outer fifths. These data show that intramyocardial pressure shuts off systolic coronary blood flow across the entire left ventricular wall at low levels of preload, and at high levels of preload determines a gradient of decreasing systolic coronary blood flow from the subepicardium to zero in the subendocardial layers. This finding suggests that a dilated or failing left ventricle receives systolic flow to the outer myocardial layers, whereas at low preload levels myocardial perfusion occurs entirely during diastole.

Relationships Between Role Clarity, Need for Clarity, and Job Tension and Satisfaction for Supervisory and Nonsupervisory Roles

Abstract: The article presents a study which explored role differences in relationships between degree of role clarity and various personal outcomes and in the moderating effects of need for clarity for supe...

Left ventricular function in patients with and without myocardial infarction and one, two or three vessel coronary artery disease

Abstract: Ninety-six patients with chest pain were studied to determine the relation between left ventricular function and severity of coronary artery disease in patients with and without a history of myocardial infarction. Coronary arteriography was performed obtaining cineangiograms (60 frames/sec) and large roll film angiograms (2 to 6 frames/sec) for precise definition of the coronary anatomy. The criteria for diagnosis of myocardial infarction were a typical history, a rise and fall in serum glutamic oxaloacetic transaminase levels and evolutionary S-T segment changes associated with Q waves of at least 0.03 second. Left ventricular function was assessed by measurement of left ventricular end-diastolic pressure and volume, and left ventricular ejection fraction, mass and compliance. Fifteen patients had normal findings; 81 were classified according to number of diseased vessels and presence or absence of myocardial infarction. There were no group differences in age or heart rate. Left ventricular end-diastolic pressure was abnormally increased in patients with three vessel disease and myocardial infarction. Left ventricular end-diastolic volume was increased and the ejection fraction was reduced in patients in each vessel disease group with myocardial infarction. Although ejection fraction was reduced in patients with three vessel disease without myocardial infarction, it was further reduced when infarction occurred. Left ventricular mass increased in patients with three vessel disease with or without myocardial infarction. Values for ventricular compliance were reduced in all patients with myocardial infarction and were lower in those with two and three vessel disease and infarction than in those with two and three vessel disease without infarction. These findings suggest that a previous history of myocardial infarction needs to be considered together with anatomic abnormalities of the coronary arteries in assessing cardiac performance in patients with ischemic heart disease. In patients with one, two or three vessel coronary artery disease, a previous myocardial infarction significantly alters left ventricular performance; the ejection fraction is a more sensitive measurement of left ventricular function than left ventricular end-diastolic pressure or volume.

Variable effects of heart rate on phasic and regional left ventricular muscle blood flow in anaesthetized dogs

Abstract: Tachycardia to 240 beats/min in anaesthetized dogs increases coronary blood flow while flow in the left ventricular wall remains homogeneous. An arteriovenous fistula causes subendocardial ischaemia at 120 beats/min but pacing to 180 to 210 beats/min increases subendocardial blood flow by increasing diastolic coronary driving pressure per minute.

Theoretical studies in photoelectron spectroscopy. Molecular optical activity in the region of continuous absorption and its characterization by the angular distribution of photoelectrons

Abstract: The phenomenon of molecular optical activity is examined in the region of continuous absorption. When the "excited" state of the molecule describes an infinite (ionized) system, then the angular distribution of photoelectrons is the sum of coherent contributions corresponding to different magnitudes and interferences of $\ensuremath{\hbar}\stackrel{\ensuremath{\rightarrow}}{1}$, the angular momentum of the photoelectron. The amplitude for such a process is the sum of terms for each $l$; thus, since both even and odd values of $l$ can coexist at a single energy in the continuous spectrum, the electric and magnetic dipole matrix elements can coexist in this amplitude, making possible the existence of electric-dipole-magnetic-dipole interference in the angular distribution even for a molecule with a center or plane of symmetry. For discrete absorption, in which the intensity is the sum of incoherent contributions corresponding to the intensities for populating the fine-structure levels of a given excited state, the coexistence of the electric and magnetic dipole matrix elements in the amplitude is possible only for a molecule with a site which is asymmetric with respect to inversion or reflection; otherwise both even and odd values of $l$ could not coexist at a single energy in the discrete spectrum. The signs of the electric-dipole-magnetic-dipole interference terms are opposite for left and right circularly polarized light; thus there exists a signal for the angular distribution difference for absorption of left and right circularly polarized light of order $\ensuremath{\alpha}$ relative to the angular distribution for absorption of light of either polarization. This is just the phenomenon of "circular dichroism" which characterizes molecular "optical activity" in the region of absorption. It exists for the angular distribution of photoelectrons ejected from an oriented molecule with a center or plane of symmetry, but vanishes for isotropic systems (atoms) owing to the independence of the radial wave functions from the magnetic quantum number. This ensures the orthogonality of atomic radial wave functions belonging to states of different $m$ and is responsible for the selection rule in atomic spectroscopy that magnetic-dipole transitions are possible only between the fine-structure levels of a given multiplet. Measurement of the angular distribution characteristic for this process would provide a sensitive probe of the parameters of the initial molecular orbital. The existence of even-odd-type interferences of the partial waves of the photoelectron would provide a test of the time-reversal invariance of the wave function for the ionized system, since these interferences depend on the sine rather than the cosine of the phase-shift difference and hence on the normalization of the wave function to satisfy incoming boundary conditions. Calculations are carried out to illustrate these and other points.

Revision of Trillium subgenus Phyllantherum (Liliaceae)

Abstract: A taxonomic revision, based mainly on morphological and distributional criteria, is presented for all taxa ofTrillium subgen.Phyllantherum Raf., which is characterized by sessile flowers. The 22 species recognized as valid include 17 morpho-geographical species in the eastern United States and five in the northwestern United States and California. These species form three morphological alliances that are characterized informally as “species groups.” All the taxa are described, and a key to species and varieties is provided. Five new species are described:Trillium decipiens, T. reliquum, T. foetidissimum, T. albidum, and T. kurabayashii; and a new status,T. angustipetalum (Torrey) Freeman, based onT. sessile var.angustipetalum Torrey, is proposed. Six new flower color forms are described:T. reliquum f. luteum, T. stamineum f. Iuteum, T. maculatumF. luteum, T. maculatum f. simulans, T. foetidissimum f. luteum, and T. cuneatum f. luteum. County distribution maps are included for all species and varieties, and an annotated synonymy is presented for each taxon.

Bionomics of the Organ-Pipe Mud-Dauber, Trypoxylon politum (Hymenoptera: Sphecoidea)

Abstract: The life history and habits of Trypoxylon (Trypargilum) politum Say were studied intensively in westcentral Alabama during 1972–74. Information concerning range, nest location and construction, provisioning, cocoon construction and orientation, prey hunting, parasites and inquilines, mating, and nesting success is given. Division of labor between sexes and pairing constancy is also discussed.

A New, Dimorphic Species of Pyemotes and a Key to Previously-Described Forms (Acarina: Tarsonemoidea)

Abstract: Two male and 2 female forms of a new, dimorphic species of Pyemotes from the scolytid Phleosinus canadensis Swaine are described and life history notes are presented. Only one type of female was found to be phoretic. Normal and phoretomorphic females can produce both normal and phoretomorphic daughters. Two species groups in Pyemotes , the scolyti group and the ventricosus group, are recognized and comparisons of morphological and behavioral adaptations for phoresy are made. Crossing experiments involving several forms indicate the probable existence of several closely related species in the ventricosus group, these often overlapping in their choice of hosts. A key to males of the genus and to females of the scolyti group is presented.

Phoretomorph: a New Phoretic Phase Unique to the Pyemotidae (Acarina: Tarsonemoidea)

Abstract: The phoretomorph, representing a new type of phoresy for the Acarina, is a female specialized for riding insects. Certain pyemotid species possess both phoretomorphic and non-phoretomorphic females, but others are monomorphic and have one or the other.

The pathologic behavior of primary vaginal carcinoma and its relationship to cervical cancer.

Abstract: The surgical pathology files at the University of Alabama Medical Center for 1958 through 1973 contain records of 157 cases of vaginal carcinoma. Of the 141 patients on whom complete records are available, 37 had primary and 104 secondary vaginal carcinoma. Only 3 of the primary vaginal malignancies were adenocarcinoma; the rest were epidermoid. The microscopic appearance of these carcinomas was frequently lateral spreading or papillary, but in a few instances the growth pattern was submucosal. Prognosis appeared to be related to the stage of the disease. Vaginal carcinomas associated with cervical cancer clustered either within 1 year or 5 years after the therapeutic treatment. In this paper, the relationship between primary vaginal cancer and cervical cancer is discussed.

A model for the coevolution of the genetic code and the process of protein synthesis - Review and assessment

Abstract: The contemporary genetic code and the process of protein biosynthesis most assuredly evolved from a simpler code and process. We believe that there was obligatory coevolution of the two and that the earlier code and process must have involved a more direct linkage between the amino acids and the informational macromolecule. We propose that an early form of translating existed in which amino acids were attached directly to the ‘messenger’ RNA along the backbone as 2’OH aminoacyl esters. These esters then condensed with each other on the RNA backbone yielding a peptide covalently attached to the RNA, without the use of tRNAs and ribosomes. This presentation is concerned with experimental data which indicate that such a simple translation system is possible and must have involved the following steps: (1) formation of the aminoacyl adenylate anhydride, (2) transfer of the amino acid from the adenylate to imidazole, (3) transfer of the amino acid from imidazole to 2’OH groups along the backbone of RNAs, (4) condensation of the amino acids to yield peptides. Steps (1)–(3) have been confirmed in chemical systems. Our preliminary evidence indicates step (4) is also possible. The aminoacylation of polyribonucleotides and the subsequent formation of peptides is a dynamic and experimentally accessible system for studying genetic coding specifities and our present studies are now concentrated on step (4), looking for such specifities.