Showing papers by "Wake Forest University published in 1982"

Modification of benthic insect communities in polluted streams: combined effects of sedimentation and nutrient enrichment

Abstract: Responses of the benthic insect community of a southern Appalachian trout stream to inorganic sedimentation and nutrient enrichment were monitored over a period of eight months. Entry of pollutants from point sources established differentially polluted zones, allowing an assessment of impacts due to sedimentation alone and in association with elevated nutrient levels. Input of sediment resulted in a significant increase in bed load and decrease of pH at the substrate-water interface (P < 0.05). The zone receiving nutrient runoff from livestock pasture exhibited elevated levels of nitrate and phosphate, but available data indicated such concentrations to be quite low. Species richness, diversity, and total biomass of filter feeding Trichoptera and Diptera, predaceous Plecoptera, and certain Ephemeroptera were significantly reduced in the polluted zones. Inorganic sedimentation, operating indirectly through disruption of feeding and filling of interstitial spaces, was considered to be the primary factor affecting filter feeding taxa. Decomposition of compounds associated with materials in the bed load may depress pH and eliminate acid sensitive species of Plecoptera and Ephemeroptera. Such processes of acidification may be particularly important to Appalachian streams since the pH of regional surface waters is characteristically acidic prior to sedimentation. Accumulation of particles on body surfaces and respiratory structures, perhaps as a function of wax and mucous secretion or surface electrical properties, appears to be the major direct effect of inorganic sedimentation on stream insects. Growths of the filamentous bacterium Sphaerotilus natans were also frequently associated with silted individuals in the zone receiving nutrient addition. Distribution of the bacterium suggested that silted substrates, perhaps as related to the presence of iron compounds, are required for colonization in dilute nutrient solutions. The primary effect of Sphaerotilus colonies appears to be augmentation of particle accumulation through net formation by bacterial filaments. Data indicate that inorganic sedimentation and nutrient addition operate synergistically, eliminating a significantly greater number of taxa than exposure to one pollutant alone.

Hypocalcemia in critically ill patients.

Abstract: Hypocalcemia is an important metabolic problem in critical care medicine. To determine the frequency of this problem and the patient subsets at risk, a retrospective study of a large series of ICU patients was performed. During the study period, 259 patients were admitted to the ICU, of whom 210 (81

The Concept of Observation in Science and Philosophy

Abstract: The solar neutrino experiment, designed to test our fundamental theories of the source of energy which sustains the stars and life, is one of the most sophisticated and important experiments of the past two decades. But it leads to some philosophical puzzles. For although the central core of the sun lies buried under 400,000 miles of dense, hot, opaque material, astrophysicists nevertheless universally speak of the experiment as providing “direct observation” of that central core. What can be meant by such talk? Is the puzzled philosopher simply ignorant of the ingenuity of modern science? Or are the astrophysicists using the term loosely or incorrectly or misleadingly, in a kind of sociological aberration that philosophers must gently tolerate while realizing that that usage has nothing to do with “real” observation? Or are the philosopher and astrophysicist perhaps interested in entirely different and unrelated problems, their respective usages being, from their respective points of view, equally legitimate? Or are the usages perhaps related, but in ways more complex than might be supposed from these or other usual alternatives?

Loneliness and patterns of self-disclosure.

Abstract: The first study in this paper examined the hypothesis that feeling lonely is related to a self-perceived lack of self-disclosure to significant others. Thirty-seven male and 38 female undergraduates rated themselves on the UCLA Loneliness Scale and the Jourard Self-Disclosure Questionnaire. Analyses showed that for males and females, loneliness was significantly and linearly related to a self-perceived lack of intimate disclosure to opposite-sex friends. For females, loneliness was also associated with a perceived lack of self-disclosure to same-sex friends. The second study investigated the relationship between loneliness and actual disclosure behavior. Twenty-four lonely subjects and 23 nonlonely subjects were paired with nonlonely partners in a structured acquaintanceship exercise. Both opposite-sex pairs and same-sex pairs were included in the design. Postexercise ratings by partners indicated that lonely subjects were less effective than nonlonely subjects in making themselves known. Analysis of the intimacy level in the conversations showed that lonely subjects had significantly different patterns of disclosure than nonlonely subjects. We suggest that the self-disclosure style of the lonely person impairs the normal development of social relationships.

Panendoscopy as a screening examination for simultaneous primary tumors in head and neck cancer: a prospective sequential study and review of the literature.

Abstract: A prospective panendoscopic evaluation comprising direct laryngoscopy, bronchoscopy, and esophagoscopy was conducted in 100 consecutively seen patients with untreated head and neck primary tumors. Of the patients, 16% (18% counting two third primary lesions found in the 16 patients) had synchronous primary malignant tumors of the aerodigestive tract. Eleven of the 16 patients had silent lesions found only by endoscopy, and 6 (6% of the total group) had lesions found only because the full panendoscopic protocol was followed. Those 6 tumors would not have been discovered as early by clinical examination or by symptom-only directed studies. The initial treatment plan in 7 patients was changed by the panenodscopic findings, This study verifies the high incidence of synchronous primary tumors in the head and neck areas that have been reported in retrospective studies, and suggests that an intensive, full panendoscopic work-up as a screening test in all patients with primary head and neck tumors can be conducted without increased morbidity and yields enough information to justify its cost.

Ether lipid content and fatty acid distribution in rabbit polymorphonuclear neutrophil phospholipids.

Abstract: This study was undertaken to determine if rabbit neutrophils contain sufficient ether-linked precursor for the synthesis of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activatin factor) by a deacylation-reacylation pathway. The phospholipids from rabbit peritoneal polymorphonuclear neutrophils were purified and quantitated, and the choline-containing and ethanolamine-containing phosphoglycerides were analyzed for ether lipid content. Choline-containing phosphoglycerides (37%), ethanolamine-containing phosphoglycerides (30%), and sphingomyelin (28%) were the predominant phospholipid classes, with smaller amounts of phosphatidylserine (5%) and phosphatidylinositol (<1%). The choline-linked fraction contained high amounts of 1-O-alkyl-2-acyl-(46%) and 1,2-diacyl-sn-glycero-3-phosphocholine (54%), with a trace of the 1-O-alk-1′-enyl-2-acyl species. The ethanolamine-linked fraction contained high amounts of 1-O-alk-1′-enyl-2-acyl-(63%) and 1,2-diacyl-sn-glycero-3-phosphoethanolamine (34%), and a low quantity of the 1-O-alkyl-2-acyl species (3%). The predominant 1-O-alkyl ether chains found in thesn-1 position of the choline-linked fraction were 16∶0 (35%), 18∶0 (14%), 18∶1 (26%), 20∶0 (16%), and 22∶0 (9%). The major 1-O-alk-1′-enyl ether chains found in thesn-1 position of the ethanolamine-linked fraction were 14∶0 (13%), 16∶0 (44%), 18∶0 (27%), 18∶1 (12%) and 18∶2 (3%). The major acyl groups in thesn-1 position of 1,2-diacyl-sn-glycero-3-phosphocholine and 1,2-diacyl-sn-glycero-3-phosphoethanolamine were 16∶0, 18∶0 and 18∶1. The most abundant acyl group in thesn-2 position of all classes of choline- and ethanolamine-linked phosphoglycerides was 18⩺2. Although this work does not define the biosynthetic pathway for platelet activating factor, it does show that there is ample precursor present to support its synthesis by a deacylation-reacylation pathway.

Multiple simultaneous tumors in patients with head and neck cancer. A prospective, sequential panendoscopic study

Abstract: A prospective panendoscopic study (bronchoscopy, laryngoscopy, esophagoscopy) was carried out in 81 consecutively seen, untreated patients newly diagnosed as having a mucosal neoplasm in the upper aerodigestive tract, to determine how many had a synchronous second primary lesion of the aerodigestive tract. Fourteen patients (17%) proved to have multiple primary lesions (14 second-primary and two third-primary lesions). Three lesions were hypopharyngeal, six esophageal, three pulmonary, two laryngeal, and two oropharyngeal. Two of the additional lesions were found during routine head and neck examination, nine lesions would have been found with a single routine symptom- or roentgenogram-directed endoscopic examination; five, because of their location or small size, would not have been found without panendoscopy, even after chest roentgenography, indirect laryngoscopy, and barium esophagography had been done. The most productive endoscopic examinations for detecting second primary lesions were esophagoscopy and laryngoscopy, the former detecting six lesions, the latter five lesions. The yield of chest roentgenograms was low (1/79). No complications resulted from this prospective panendoscopic protocol study. THese findings should reinforce the belief that head and neck cancer is a panmucosal disease of the aerodigestive tract, that silent second synchronous primary lesions are not uncommon, and that every effort should be made to find all primary sites before treatment of the index tumor is begun.

Cross-validation of the factor structure of the McGill Pain Questionnaire

Abstract: Low back pain patients' responses to the McGill Pain Questionnaire (MPQ) were factor analyzed using the principal factor method and direct oblique rotation procedures. Four factors were extracted that accounted for 55% of the total variance. Coefficients of congruence were computed in order to relate the current factors with those extracted in a previous factor analytic investigation. The results provided positive evidence that the sensory pressure, evaluative, and affective-sensory factors that were previously identified are stable dimensions underlying the MPQ responses of low back pain patients. However, it is necessary to conduct further cross-validation studies using patients from a wide variety of treatment settings.

β Decay and the origins of biological chirality: theoretical results

Abstract: A dynamical mechanism is found whereby a dissymmetric molecule and its mirror image are ionized at different rates by longitudinally polarized electrons such as produced by nuclear β decay. An enhancement is predicted for molecules containing heavy atoms. Order-of-magnitude estimates indicate that the asymmetric effect of this mechanism may be detectable by current experiments on positronium formation.

The costs of reproduction in brine shrimp

Abstract: Brine shrimp were subjected to one of four reproductive regimes: complete absence of mating, mating postponed for 20 d or 40 d past sexual maturity, or continuous breeding upon sexual maturity (controls). Each of the four reproductive regimes was further subdivided into low and high feeding groups (1:10 feeding ratio). Under low food, female lifespan was negatively correlated with the length of the reproductive period. However, no such relationship was found among the four high food groups; no intrasex differences were found in survival curves or mean length of lifespan. Fertile females in the delayed reproduction groups gave birth to approximately the same total number of offspring as controls, not by lengthening lifespan but by producing larger broods, with fewer days between broods. The results indicate that although some reproductive costs are unavoidable, nutri- tional resources play a critical role in determining how extensively reproduction will affect lifespan.

In Vivo Evidence for Increased Adrenal Sensitivity to Adrenocorticotropin-(l–24) in the Lamb Fetus Late in Gestation

Abstract: Plasma concentrations of immunoreactive ACTH and cortisol were monitored daily in chronically cannulated sheep fetuses during the last 3 weeks of gestation. A prepartum increase in fetal plasma cortisol occurred without a concomitant rise in fetal plasma ACTH. When fetal lambs were injected with various doses of ACTH-(l–24) and the plasma cortisol responses were integrated over time, the resulting changes in the log dose-response curves indicate that fetal adrenal sensitivity increases late in gestation. Thus, the marked rise in fetal plasma cortisol before birth can be explained, at least in part, by an increase in fetal adrenal sensitivity to ACTH.

Effects of gossypol on reproductive and endocrine functions of male cynomolgus monkeys (Macaca fascicularis).

Abstract: Adult male cynomolgus monkeys were treated orally with 5 (n=4) or 10 (n=3) mg per kg per day of gossypol acetic acid (gossypol) for 6 months. A significant decrease in sperm concentration and motility,determined by evaluating semen ejaculates,was observed without any significant decrease in circulatinglevelsof testosterone (T) among 10 mg per kg per day gossypol-treated animals. Similarly, there was no significant difference in plasma T levels after an intravenous bolus injection of luteinizing hormone releasing hormone (LHRI-l) (50 �sg/animal) between control and gossypol-treated animals, further suggesting an adequate release of pituitary luteinizing hormone (LH) and normal Leydig cell function. Transient azoospermia was observed in 1 out of 4 and in 2 out of 3 animals after 4 months of gossypol treatment at 5 and 10 mg per kg per day, respectively. The effects of gossypol (10 mg per kg per day) were more dramatic and consistent on sperm motility. No striking abnormality of spermatozoa was observed by light microscopy, although there was an increase in the number of sperm with coiled or broken tail pieces and an occasional detached head and tail. However, at the ultrastructural level disruption of the axial complex was commonly observed with gossypol treatment. The effect was manifested at 5 mg per kg per day as a disruption of radial arms. At 10 mg per kg per day the entire axial complex was frequently destroyed, suggesting an impairment of sperm motility. No serious clinicopathologic side effects were observed except temporary diarrhea and anorexia among 10 mg per kg per day gossypoltreated animals during the initial stages of treatment. In addition, gossypol had a hypolipidemic effect which is a new significant entity for this compound. In conclusion, it is suggested that gossypol may be interfering with spermatogenesis and/or directly acting on the sperm itself within the testis or during its passage through the male reproductive tract in ways thataffectboth sperm production and sperm motility.

Ethanol-induced alterations in the morphology and function of the rat ovary

Abstract: The purpose of this study was to compare the effects of different dosages of ethanol on ovarian morphology and function. Holtzman rats, 20 days old, were divided into groups as follows: The rats in Group I were autopsied at 20 days of age, and those in Group II were placed on ad libitum chow and water diet; the rats in Groups III and V were fed on a liquid diet containing 2.5% or 5% ethanol respectively; Groups IV and VI were pair-fed controls to Groups III and V, respectively. Rats in Groups II, III, IV, and VI were maintained on the diets for 50–55 days and killed at late proestrus-estrus, while the animals in Group V did not exhibit estrous cycles and were killed on day 55 of treatment. The average increase in body weights of rats in Groups II, III, and IV was significantly greater than the increase in body weights of rats given 5% ethanol or their pair-fed controls. In the rats treated with 5% ethanol, vaginal opening was significantly delayed from the controls, estrous cycles were absent, ovarian weights were similar to those of the 20-day-old rats, ovaries contained corpora lutea of only one estrus, uteri weighed less than controls, and histologically, the uteri and vaginae were similar to those of 20-day-old rats. However, in the rats treated with 2.5% ethanol, all of the parameters were similar to those of the controls. The average serum alcohol level for the rats on the 5% ethanol diet was 249 mg%; the serum alcohol levels were at the lower limit of detection for the rats on the 2.5% ethanol diet. The data show that ovarian function was suppressed in the rats that received the 5% ethanol but not in rats on the 2.5% ethanol diet.

Micellar Enhanced Spectrofluorimetric Methods: Application to the Determination of Pyrene

Abstract: The effects of cationic hexadecyltrimethylammonium chloride (CTAC), nonionic polyoxyethylene (9.5)p-1, 1, 3, 3-tetramethylbutylphenol, Triton X-100 (TX-100), and anionic sodium dodecylsulfate (NaLS) surfactant micelles upon the spectrofluorimetric determination of pyrene is described. It was found that the intensity of the pyrene fluorescence is enhanced from 3 to 16 times in the presence of the micellar systems. Possible reasons for this micellar induced enhanced fluorescence are discussed. The spectral parameters, fluorescence lifetimes, quantum yields, lower detection limits, and analytical figures of merit for pyrene in CTAC, NaLS, TX-100, ethanol, and water are compared. The detection limit of pyrene in the presence of micelles (∼1.0 × 10−10 M) is about an order of magnitude lower than that possible in alcohol alone. A brief discussion on the predicted general applicability of this new technique in fluorimetric analyses is also given.

The physics of proton NMR.

Abstract: The physics of pulse NMR which is pertinent to an understanding of proton NMRimaging has been condensed and directed toward the medical physicist. The basic physical principles of spin manipulations using rf pulses are presented, and the relation between the quantum mechanical and the classical descriptions is covered in a rigorous fashion. The physics of relaxation is described and the relaxation timesT 1 and T 2 are explained in some detail. Application of these spin manipulation techniques is illustrated by showing how they may be used in creating an image.

Control of adenine nucleotide metabolism in hepatic mitochondria from rats with ethanol-induced fatty liver.

Abstract: Male rats developed fatty liver after being fed on an ethanol-containing diet for 31 days. Liver mitochondria from these animals catalysed ATP synthesis at a slower rate when compared with mitochondria from pair-fed control rats (control mitochondria), and demonstrated lowered respiratory control with succinate as substrate, owing to a decrease in the State-3 respiratory rate. Respiration in the presence of uncoupler was comparable in mitochondria from both groups of rats. Translocation of both ATP and ADP was decreased in mitochondria from ethanol-fed rats, with ADP uptake being lowered more dramatically by ethanol feeding. Parameters influencing adenine nucleotide translocation were investigated in mitochondria from ethanol-fed rats. Experiments performed suggested that lowered adenine nucleotide translocation in these mitochondria is not the result of inhibition of the translocase by either long-chain acyl-CoA derivatives or unesterified fatty acids. Analysis of endogenous adenine nucleotides in these mitochondria revealed lowered ATP concentrations, but no decrease in total adenine nucleotides. In experiments where the endogenous ATP in these mitochondria was shifted to higher concentrations by incubation with oxidizable substrates or defatted bovine serum albumin, the rate of ADP translocation was increased, with a linear correlation being observed between endogenous ATP concentrations and the rate of ADP translocation. The depressed ATP concentration in mitochondria from ethanol-fed rats suggests that the ATP synthetase complex is replenishing endogenous ATP at a slower rate. The lowered ATPase activity of the ATP synthetase observed in submitochondrial particles from ethanol-fed animals suggests a decrease in the function of the synthetase complex. A decrease in the rate of ATP synthesis in mitochondria from ethanol-fed rats is sufficient to explain the decreased ADP translocation and State-3 respiration.

Multiple Primary Malignant Tumors (MPMT): Study of 68 Autopsy Cases (1963–1980)

Abstract: Review of 8428 autopsies (1870 for known cancer) showed that 68 patients had had multiple primary malignant tumors (MPMT). Those 68 cases represented 0.8 per cent of all autopsies done, 3.6 per cent of all cancer autopsies. Diagnosis of MPMT was made only at autopsy in 24 cases (35.3 per cent). Thirty-six patients were male, 32 female. Their average age was 64 ±usmn;2.3 years. Cancers were “synchronous” (diagnosed within a six-month period) in 15 patients, “metachronous” (diagnosed at greater than six-month intervals) in 49, and “combined” in four. Metastatic foci were seen in 53 patients. Fifty-nine patients had two primary malignant tumors (PMTs); seven had three PMTs; one had four PMTs; and one had five PMTs, for a total of 148 tumors. Over half (53.1 per cent) of the second PMTs occurred within five years of the first PMTs. First PMTs were most common in the hematopoietic system and the cervix; second PMTs were most common in the lungs and the hematopoietic system. Second PMTs were less well differentiated than index PMTs. Forty-four deaths had not been directly tumor-related. Nineteen patients with metachronous MPMT lived more than ten years. Of 23 patients with one pulmonary PMT, 22 died within two years. Concomitant findings of pulmonary artery embolism, gallstone(s), thyroid or prostatic hyperplasia, and benign tumor were common in these patients. It is hoped that accumulation of data from this and other series of MPMT will provide insight into the clinicopathologic characteristics, the causes, and the interrelationships of these lesions that constitute primarily a disease of the elderly.