Showing papers by "University of Alabama published in 1970"

Cardiac conduction system: fetal and postnatal development.

Abstract: Development of the cardiac conduction system is considered from the standpoint of its fetal, neonatal and adult anatomy, histology and pathology. The perspectives provided by these multiple approaches indicate that postnatal developmental changes in the conduction system are extensive and important. The sinus node originates in the sinus venosus but subsequently a dense collagen framework develops, directly attached to a disproportionately large and consistently located central artery. Partitioning of the sinus node by collagen is important relative not only to the nature of its cellular development but also to its pacemaking function. A functional relation between pulse and impulse in the sinus node and a balancing postnatal maturation of its autonomic innervation are two of the important stabilizing influences in the optimal development of the adult sinus node as a pacemaker. The interatrial and internodal pathways develop precisely in the region of the primitive sinus venosus and provide the efficient means for selective conduction within the atria. The postnatal closure of the foramen ovale establishes the final form of the atrial septal route of these pathways, and malformation of the septum or the venous valves will lead to altered atrial conduction routes. Evidence is cited to support the concept that the atrioventricular (A-V) node and His bundle originate as separate structures that join together very early in fetal development. Histologic differences between the internal structure of the sinus node and A-V node are discussed, particularly as they relate to the pacemaking function of the nodes. Postnatal molding and shaping of His bundle is associated with cell death, just as morphogenesis usually is, but because of the small size and critical importance of the His bundle, this postnatal developmental change is fraught with potentially dangerous functional consequences.

Memory Processes in Retardates and Normals1

Abstract: Publisher Summary This chapter discusses the memory processes in retardates and normals. Most studies of short term memory (STM) in the retardate have relied principally upon delayed response, digit span, or some type of learning task in which time relations were varied. Since the stimulus trace hypothesis, much of the research has also employed questionable methodologies. This chapter describes a series of studies that bear on the long-term memory–short-term memory (LTM–STM) distinction as well as on normal-retardate differences in STM. It describes the experimental model, methodological studies, a theoretical schema, and a series of studies that provide evidence for two STM processes in normal and retarded Ss as well as evidence that retardates suffer a deficit in rehearsal strategies; a mechanism of central importance to short-term storage. The results obtained with these studies suggest that two processes are involved in the short-term storage of supraspan messages. In institutionalized retardates, one of these processes is defective— that is, it fails to function in a normal fashion. Active rehearsal strategies are necessary for one of the storage processes but apparently not for the other.

Estimation of Stroke Volume in the Dog by a Pulse Contour Method

Abstract: A method for estimating the stroke volume (SV) from the systolic area of a single-channel record of the central aortic pressure has been tested in 12 anesthetized open-chest dogs. The formula used was SV = K·Psa·(1 + Ts/Td), where Psa is the area under the systolic part of the curve above end-diastolic pressure, Ts and Td are the durations of systole and diastole, respectively, and K is an arbitrary constant derived from measurement of an initial SV by electromagnetic flowmeter in each dog and used thereafter without change, in that dog. In the 12 dogs, 541 simultaneous determinations of SV by the pressure contour and electromagnetic flowmeter methods were compared under normal and altered circulatory conditions employing 12 different interventions. The total range of SV was 2.4 to 28.1 ml, of heart rate 35 to 207/min, and of mean arterial pressure 24 to 166 mm Hg. The overall correlation coefficient (r) was 0.928 with a regression line y = 1.04x + 0.21 ml (SE) of estimate, ±17.4%. Except for three sympathomimetic drugs, the r values for all other interventions ranged from 0.93 to 0.99. These observations compare favorably with those of previously reported pulse contour methods. The windkessel origin of the formula is noted, and a new derivation from a modification of the "water-hammer" equation is given.

Response to synthetic thyrotropin-releasing hormone in man

Abstract: The response to thyrotropin-releasing hormone (TRH) has not been delineated in man, nor have patients with endocrinopathies been tested yet with this agent. The purpose of this communication is to report the serum TSH of euthyroid subjects given TRH by several modes of administration and to describe the response in several patients with endocrinopathies.

Left Ventricular Chamber Volume, Mass, and Function in Severe Coronary Artery Disease

Abstract: Twenty-three patients, 15 of whom had clinical and electrocardiographic evidence of previous myocardial infarction, were studied by coronary arteriography and biplane angiocardiography. End-diastolic volume ranged from 55 to 317 ml/m2, left ventricular mass from 83 to 294 g/m2 and ejection fraction from 0.13 to 0.75. An increased enddiastolic volume was associated with an increased left ventricular mass (r = 0.77, P < 0.01). In 15 of the 23 patients mitral regurgitant volume ranged from 0.7 to 4.7 L/min/m2 and an end-diastolic volume greater than 154 ml/m2 was associated with mitral regurgitation. The ejection fraction was significantly reduced in the absence as well as the presence of mitral regurgitation. These observations on coronary artery disease in 23 patients with refractory angina pectoris or persistent congestive heart failure, or both, reveal that in this group of patients (1) a dilated left ventricle was hypertrophied and the extent of hypertrophy was proportional to the dilatation; (2) an enl...

Acute Alterations of Body Composition after Open Intracardiac Operations

Abstract: The body composition of patients with heart disease is acutely altered by surgical intervention. Interrelations and causes of the alterations have not been clear. Twenty patients were studied preoperatively and again 2 to 4 days after open intracardiac operations. In nine, measurements were made of the volumes of total body water, extracellular water, plasma, and red cells, and of the amounts of total exchangeable sodium and potassium. In an additional four patients total exchangeable sodium and potassium were measured, and in another seven only exchangeable sodium was measured. Calculations were made of the intracellular and extracellular distribution of water and potassium. The significant changes (P < 0.05) occurring during the interval between studies were increase in extracellular water (7%), interstitial water (12.5%), and exchangeable sodium (9.4%), decrease in total exchangeable potassium (8.5%) and amount (8.7%), and concentration (6.9%) of calculated intracellular potassium. Uptake of sodium and...

Bromide space studies in infants of low birth weight.

Abstract: Extract: The present study reports measurements of the corrected bromide space (CBS) in 74 neonates delivered vaginally and studied within 24 h of birth. The results in 37 normally grown (NG) infants ranging in birth weight from 960 to 3,450 g with gestational intervals of 27–43 weeks are contrasted with findings in 37 intrauterine growth-related infants (IGR) ranging from 1,000 to 2,460 g in birth weight with gestational intervals of 35–44 weeks. Although a direct relation exists between CBS (liters) and a varicty of variables of fetal maturity in both NG and IGR infants, the CBS in both groups would appear best related to birth weight. The corrected bromide space of IGR was virtually identical with that of their weith peers, there being no significant difference in the regression for CBS versus birth weight in the two groups. Log-log plot of this relation yields a correlation coefficient (r) of 0.98, and may be expressed as: log CBS (liters) = 0.92 × log wt (kg) - 0.371 Closer inspection of this relation revealed that an unequal distribution, with preponderance of values below the regression line at higher birth weights, was apparent. That ‘tail off’ suggested a curvilinear relation of CBS with increasing birth weitht, and was even more apparent when the CBS data were expressed as percentage of bedy weight (m1/kg). The mean CBS/kg in NG prematures (424±SE 7.5 m1/kg) was clearly higher (p <0.001) than in mature study infants (376±SE 8.4 m1/kg). Likewise, the average CBS/kg in the mature IGR (419±SE 11.3 m1/kg) was significantly higher (p <0.025) than the mean for the NG infants (376±SE 8.4 m1/kg). Conparison of data from NG and IGR infants revealed that 3 of 10 premature infants and 10 of 27 mature IGR infants have a CBS/kg more than 2 SD above the mean in NG infants; a CBS in excess of 476 m1/kg was observed in 11 study infants, all but 1 of whom were IGR. Speculation: Characteristically, expansion of body water compartments accompanies postnatal malnutrition. In intrauterine growth retardation, similar changes in body fluid compartments suggest an etiologic role for ‘fetal malnutrition’ in the disorder.

Cadmium and zinc abnormalities in bronchogenic carcinoma.

Abstract: During a study of renal cadmium content in hypertension, it was coincidentally observed that renal cadmium was elevated in persons with neoplasia. Therefore, a detailed study was made of cadmium concentration in renal and hepatic tissue and blood of persons with bronchogenic carcinoma. Cadmium was significantly increased in all 3 tissues in bronchogenic cancer. Because of the close relationship between zinc and cadmium in nature, zinc concentrations were also measured. Zinc levels were not significantly different in liver, tended to be high in kidney, and were significantly lower in blood. Similar changes in cadmium concentration were not seen in a group of other neoplastic diseases. The significance of these observations is not clear.

A relationship between whole body impedance and total body water volume

Abstract: The electrical phenomena of biological systems has intrigued scientific investigators for many years. Our investigations were concerned with the measurement of total body electrical impedance as a biological parameter that could be used together with other data to predict total body water. Our interest in this area resulted from Thomasset’s’ studies with use of whole body impedance as a measurement of total body water. Electrical impedance measurements have been used by other investigators in the study of arterial pulse wave forms and pulsatile flow in various organs.2.3 We felt that a simple bedside method for determining body compartment fluid volumes would be a valuable clinical tool in managing fluid and electrolyte problems and in body composition studies. Our studies indicate that a definable relationship may exist between body impedance and body water volume. The hypothesis that impedance can be used to measure total body water is based on the following principle: The impedance of simple geometric systems is a function of conductor configuration and length, its cross-sectional area, and the measuring signal frequency. With use of a fixed signal frequency and a relatively constant conductor configuration, the impedance then becomes a function of conductor length and cross-section, or conductor volume. Therefore, assuming signal frequency and conductor configuration to be constant, the impedance to the flow of current can be related to the size, or volume, of the conductor. This relationship is shown as follows: Z = pL/A, where Z = resistance in ohms, p = specific resistivity in ohm-centimeters, L = length in centimeters, A = cross-sectional area in square-centimeters. Multiplying by L / L gives Z = pL2/ AL; since AL = V (or volume), rearranging then gives V = pL2/Z. While there are many difficulties in applying this principle to a system with such complex geometry as the human body, this relation is presented as a background, and as one possible explanation for the empirical relationship to be presented subsequently. MATERIALS AND METHODS

Sexual Differences in Physical Attractiveness as a Determinant of Heterosexual Liking

Abstract: A questionnaire study of sexual differences in the importance of physical attractiveness to heterosexual liking disclosed that 177 men ranked physical attractiveness significantly (but only slightly) higher than 177 women. Different degrees of intimacy and permanency in the relationship also affected the importance of physical attractiveness in partners. There was no significant interaction between sex and type of relationship.

Student Acceptance of Bogus Personality Interpretations Differing in Level of Social Desirability

Abstract: 119 unsuspecting college students were given a personality drawing test and weeks later received 12 faked interpretive statements. The majority of the returned statements were written to imply soci...

Submaximal Exercise Testing in a Random Sample of an Elderly Population

Abstract: To examine the electrocardiographic response to exercise in an older population, 280 participants in a longitudinal study of cerebrovascular disease were tested. Subjects were randomly selected from the total 50 to 69-year-old population of Birmingham, Alabama. Approximately 60% of the participants reached a heart rate more than 80% of their predicted maximal heart rate. Subjects were divided into three groups on clinical grounds: (I) vascular disease, (II) risk factor(s) only, and (III) normal. Positive tests (at least 0.10 mv of ischemic ST-segment depression) were most frequent in group I (24%), though not significantly different from group II (19%) and group III (12%). Hypercholesterolemia was significantly associated with a positive exercise test only in those subjects with vascular disease. Nonspecific ST-T wave changes on the resting electrocardiogram were associated with a positive test in all subjects, but with only a borderline test in those subjects without vascular disease. No significant associations were noted between abnormal exercise test and either cigarette smoking or hypertension.

The uptake of H3‐estradiol by the oral tissues of rats

Abstract: This study was designed to determine whether H3-estradiol would localize in the oral tissues of rats. Twenty ovariectomized rats were injected subcutaneously with H3-estradiol. After injection, oral tissue including gingivae and mucosa, submandibular gland, liver, kidney, uterus and skin were dissected, weighed and homogenized. The tissues were assayed for H3-estradiol and 5 ml aliquots added to liquid scintillation fluid. The samples were read on a Beckman Liquid Scintillator. A series of experiments using the above technique demonstrated the following: (1) H3-estradiol concentrated in the oral extract when a dose of 0.136 μg/100 gm body weight or greater was given. (2) The assay of oral extract contained H3-estradiol as evidenced by chromatography. (3) One hour after injection the oral extract had the highest concentration of H3-estradiol (212 CPM/mg of tissue) while the uterus remained low (47.7 CPM/mg) in uptake. Four hours after injection there was a statistically significant increase of H3-estradiol in the uterus (118.5 CPM/mg but not a significant decrease of H3-estradiol in the oral extract (131.8 CPM/mg). (4) Estrogen (Progynon)* priming for 7 days reduced the uptake of H3-estradiol in the oral extract. Since H3-estradiol concentrates in the oral extract, it is suggested that estrogen can influence the gingival tissues on a local cellular level. The fact that estrogen priming reduced the uptake of H3-estradiol in the oral extract indicates that there may be some type of binding site in the gingivae and mucosa.

N-Way TEM-Mode Broad-Band Power Dividers

Abstract: An integrative graphical method of designing a broadband TEM-mode power divider of N output ports is presented. Each branch of the divider's circuit consists of cascaded transmission-line segments, and the corresponding segments of each branch are connected by resistors to a common junction. These resistors absorb the reflected signals due to mismatch at any of the output ports; they are therefore isolated from one another. The symmetry of this circuit permits the use of the method of even- and odd-mode excitations at the output ports. It was found that the even-mode circuit is the same as for a stepped-impedance transformer, which is well known. The odd-mode circuit lends itself to the determination of the isolation resistors using the iterative graphical procedure on a Smith chart. Numerical values of the isolation conductance for dividers of bandwidths up to 10:1, the maximum input VSWR, and the minimum isolation among the output ports are given.

Modification of extreme social isolation by contingent social reinforcement.

Abstract: Two socially isolated patients were placed on a program where social reinforcement from staff members was made dependent on social interaction with other patients or staff members. This procedure was imposed in a setting where only limited control was possible. The level of social interaction and a concomitant alternate behavior in each patient was increased when the contingency for social reinforcement was imposed. The study provides another example of the efficacy of social reinforcement where there is little control over other reinforcers. Implications for use of similar procedures to increase generalization in the community are discussed.

Synthesis and Biological Activity of Thyrotropin-Releasing Hormone1

Abstract: The synthesis of thyrotropin-releasing hormone (TRH) has been carried out by a simple solid-phase procedure with a high yield of a pure hormone. Beginning with L-proline resin ester, a residue of t-butyloxycarbonyl-Lhistidine was added. After deprotection, a residue of L-pyroglutamic acid was added. All peptidebond forming steps were conducted by the activation of the carboxyl group of the entering amino acid through the formation of its mixed anhydride with isobutylchloroformate. Cleavage of the completed peptide from the resin was accomplished by two 30-min exposures of the resin to gaseous HBr while the resin was suspended in trifluoroacetic acid. The free carboxyl group of peptide-bound proline was quantitatively converted to the amide by treating the mixed anhydride of the tripeptide and isobutylformate with anhydrous ammonia. Bioassay of this material for thyrotropin-releasing activity in mice showed it to be active at doses as low as 2 ng/mouse. The oral to iv ratio of the dose required for activit...

The Effect of the Verbal Stimulus Words Wrong, Right, and Tree on the Disfluency Rates of Stutterers and Nonstutterers

Abstract: The effects of the verbally presented stimuli wrong, right, and tree on the frequency of disfluencies during oral reading for 14 stutterers and 14 nonstutterers were studied. No differences were fo...