Chronic Stress Induces a Hyporeactivity of the Autonomic Nervous System in Response to Acute Mental Stressor and Impairs Cognitive Performance in Business Executives

The present study examined the incidence of chronic stress in business executives (109 subjects: 75 male and 34 female) and its relationship with cortisol levels, cognitive performance, and autonomic nervous system (ANS) reactivity after an acute mental stressor. Blood samples were collected from the subjects to measure cortisol concentration. After the sample collection, the subjects completed the Lipp Inventory of Stress Symptoms for Adults and the Stroop Color-Word Test to evaluate stress and cognitive performance levels, respectively. Saliva samples were collected prior to, immediately after, and five minutes after the test. The results revealed that 90.1% of the stressed subjects experienced stress phases that are considered chronic stress. At rest, the subjects with chronic stress showed higher cortisol levels, and no gender differences were observed. No differences were found between the stressed and non-stressed subjects regarding salivary amylase activity prior to test. Chronic stress also impaired performance on the Stroop test, which revealed higher rates of error and longer reaction times in the incongruent stimulus task independently of gender. For the congruent stimulus task of the Stroop test, the stressed males presented a higher rate of errors than the non-stressed males and a longer reaction time than the stressed females. After the acute mental stressor, the non-stressed male group showed an increase in salivary alpha-amylase activity, which returned to the initial values five minutes after the test; this ANS reactivity was not observed in the chronically stressed male subjects. The ANS responses of the non-stressed vs stressed female groups were not different prior to or after the Stroop test. This study is the first to demonstrate a blunted reactivity of the ANS when male subjects with chronic psychological stress were subjected to an acute mental stressor, and this change could contribute to impairments in cognitive performance.     

Comparative proteomic analyses of the yeast Saccharomyces cerevisiae KNU5377 strain against menadione-induced oxidative stress

The Saccharomyces cerevisiae KNU5377 strain, which was isolated from spoilage in nature, has the ability to convert biomass to alcohol at high temperatures and it can resist against various stresses. In order to understand the defense mechanisms of the KNU5377 strain under menadione (MD) as oxidative stress, we used several techniques for study: peptide mass fingerprinting (PMF) by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) followed by two-dimensional (2D) gel electrophoresis, liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), and surface-enhanced laser desorption ionization-time of flight (SELDI-TOF) technology. Among the 35 proteins identified by MALDI-TOF MS, 19 proteins including Sod1p, Sod2p, Tsa1p, and Ahp1p were induced under stress condition, while 16 proteins were augmented under normal condition. In particular, five proteins, Sod1p, Sod2p, Ahp1p, Rib3p, Yaf9p, and Mnt1p, were induced in only stressed cells. By LC-ESI-MS/MS analysis, 37 proteins were identified in normal cells and 49 proteins were confirmed in the stressed cells. Among the identified proteins, 32 proteins were found in both cells. Five proteins including Ye1047cp and Met6p were only upregulated in the normal cells, whereas 17 proteins including Abp1p and Sam1p were elevated in the stressed cells. It was interesting that highly hypothetical proteins such as Ynl281wp, Ygr279cp, Ypl273wp, Ykl133cp, and Ykr074wp were only expressed in the stressed cells. SELDI-TOF analysis using the SAX2 and WCX2 chips showed that highly multiple-specific protein patterns were reproducibly detected in ranges from 2.9 to 27.0 kDa both under normal and stress conditions. Therefore, induction of antioxidant proteins, hypothetical proteins, and low molecular weight proteins were revealed by different proteomic techniques. These results suggest that comparative analyses using proteomics might contribute to elucidate the defense mechanisms of KNU5377 under MD stress.     

Thrombelastographic pattern in chronic bronchopneumonia patients placed on oxygen therapy

The thromboelastographic pattern in chronic obstructive lung disease as compared to normal group during O2 administration was evaluated. The results stressed that the basal hypocoagulability of pathological subjects had become normal after O2 administration. No significant change in the group of normal subjects was observed.     

Double test of insulin sensitivity in normal and obese subjects]

13 normal and 16 obese subjects have been chosen for a double insulin tolerance test: 0,02 U/Kg of insulin were administered i.v. with an interval of 60'. The glycemic curve of the normal subjects show an identical lay out after both pulses; on the contrary the obese subjects could be divided into two subgroups. In the first one the lowering glucose action can be compared after both pulses, while in the second one the first stimulus causes a weather lowering glucose action, than in the first group, which is furtherly reduced during the subsequent pulse. An insulin resistance in these subjects is thus stressed. In the obese subjects the NEFA have a higher concentration in both groups than in the normal ones, show a normal decrease, but a certain delay is observed in the rebound phase.     

Impaired expression of high affinity interleukin 2 receptor on activated lymphocytes from patients with systemic lupus erythematosus

Peripheral lymphocytes stimulated with phytohemagglutinin (PHA-blasts) were examined for their responsiveness to exogenous interleukin 2 (IL-2). The proliferative response of PHA-blasts to IL-2 was significantly lower in patients with systemic lupus erythematosus (SLE) than in normal subjects. To clarify the reason for this defect, the expression of IL-2 receptor (IL-2R) on PHA-blasts was investigated using anti-Tac antibody and purified IL-2. Cytofluorometric analysis showed no statistical differences in the Tac positivity of PHA-blasts among normal subjects and patients with active and inactive SLE. Scatchard analysis using 125I-labeled anti-Tac monoclonal antibody revealed that the number of Tac epitopes on PHA-blasts was also not different among them. Next, the affinity of IL-2R expressed on PHA-blasts was determined by Scatchard analysis using radiolabeled IL-2 as a ligand. The number of high affinity IL-2R on the PHA-blasts was significantly decreased in patients with active and inactive SLE, as compared with normal subjects. The responsiveness of PHA-blasts to exogenous IL-2 was well correlated to the number of high affinity IL-2R, but not to the number of Tac epitopes or total IL-2R. Inasmuch as high affinity components of IL-2R are functionally active, the defective expression of high affinity IL-2R may be responsible for the T cell dysfunctions in SLE.     

The Effect of Social Stress on Chronic Pain Perception in Female and Male Mice

The current investigations on social stress primarily point to the negative health consequences of being in a stressful social hierarchy. The repetitive nature of such stressors seems to affect behavioral response to pain both in rodents and humans. Moreover, a large discrepancy in the possibility of social stresses affecting pain perception in the two genders exists. The present study examined the effect of chronic social stress on nociceptive responses of both sexes by implementing of food deprivation, food intake inequality and unstable social status (cage-mate change every 3 days) for a period of 14 days in 96 Balb/c mice. In this regard we injected 20 µl formalin 2% into the plantar surface of hind paw at the end of stress period and scored pain behaviors of all subjects, then serum concentrations of proinflammatory cytokines were measured. Our results showed that there was significant difference in chronic phase of formalin test following implementation of food deprivation and inequality (P<0.05) as compared to control group, so that pain perception was decreased considerably and this decline in inequality exposed subjects was well above isolated ones (P<0.05); whereas unstable social situation did not affect pain perception. Moreover, IL-1 and IL-6 concentrations in serum of stressed mice of both genders were well above control group (p<0.05). Finally, despite chronic pain perception in control and unstable male subjects was larger than females; the decrease of chronic pain perception in male stressed animals (poverty and inequality experienced subjects) was much more than stressed females. These results revealed that although food deprivation and social inequality can induce hypoalgesia, some socioeconomic situations like social instability don''t affect pain sensation, whereas there were similar increases of proinflammatory cytokines level in all socially stressed subjects. In addition, males display larger hypoalgesic responses to inequality as compared with females.     

To be at the right place at the right time

Diagnosing Alzheimer's disease through MRI neuroimaging biomarkers has been used as a complementary marker for traditional clinical markers to improve diagnostic accuracy and also help in developing new pharmacotherapeutic trials. It has been revealed that longitudinal analysis of the whole brain atrophy has the power of discriminating Alzheimer's disease and elderly normal controls. In this work, effect of involving intermediate atrophy rates and impact of using uncorrelated principal components of these features instead of original ones on discriminating normal controls and Alzheimer's disease subjects, is inspected. In fact, linear discriminative analysis of atrophy rates is used to classify subjects into Alzheimer's disease and controls. Leave-one-out cross-validation has been adopted to evaluate the generalization rate of the classifier along with its memorization. Results show that incorporating uncorrelated version of intermediate features leads to the same memorization performance as the original ones but higher generalization rate. As a conclusion, it is revealed that in a longitudinal study, using intermediate MRI scans and transferring them to an uncorrelated feature space can improve diagnostic accuracy.     

"In vivo" determination of hip joint separation and the forces generated due to impact loading conditions

Numerous supporting structures assist in the retention of the femoral head within the acetabulum of the normal hip joint including the capsule, labrum, and ligament of the femoral head (LHF). During total hip arthroplasty (THA), the LHF is often disrupted or degenerative and is surgically removed. In addition, a portion of the remaining supporting structures is transected or resected to facilitate surgical exposure. The present study analyzes the effects of LHF absence and surgical dissection in THA patients. Twenty subjects (5 normal hip joints, 10 nonconstrained THA, and 5 constrained THA) were evaluated using fluoroscopy while performing active hip abduction. All THA subjects were considered clinically successful. Fluoroscopic videos of the normal hips were analyzed using digitization, while those with THA were assessed using a computerized interactive model-fitting technique. The distance between the femoral head and acetabulum was measured to determine if femoral head separation occurred. Error analysis revealed measurements to be accurate within 0.75mm. No separation was observed in normal hips or those subjects implanted with constrained THA, while all 10 (100%) with unconstrained THA demonstrated femoral head separation, averaging 3.3mm (range 1.9-5.2mm). This study has shown that separation of the prosthetic femoral head from the acetabular component can occur. The normal hip joint has surrounding capsuloligamentous structures and a ligament attaching the femoral head to the acetabulum. We hypothesize that these soft tissue supports create a passive, resistant force at the hip, preventing femoral head separation. The absence of these supporting structures after THA may allow increased hip joint forces, which may play a role in premature polyethylene wear or prosthetic loosening.     

Apolipoprotein A-I metabolism in subjects with a PstI restriction fragment length polymorphism of the apoA-I gene and familial hypoalphalipoproteinemia

Familial hypoalphalipoproteinemia (hypoalpha), characterized by a decreased high density lipoprotein level, is associated with an increased incidence of premature cardiovascular disease. Restriction fragment length polymorphism analysis of genomic DNA has detected a polymorphism for the PstI restriction endonuclease near the apoA-I gene, with either a 2.2 or a 3.3 kb fragment. The latter has been previously found to occur with significantly higher frequency in probands of families with familial hypoalpha. ApoA-I was isolated from three unrelated subjects with familial hypoalpha and the 3.3 kb PstI polymorphism of the apoA-I gene, and from normal control subjects. The apoA-I from the hypoalpha subjects was structurally normal as determined by amino acid analysis and by two-dimensional gel electrophoresis. When normal apoA-I and hypoalpha apoA-I were simultaneously injected into either normal controls or hypoalpha subjects, both forms of apoA-I were catabolized at the same rate in the same subject, indicating that the hypoalpha apoA-I is also metabolically normal. Analysis of the kinetics of metabolism of apoA-I in the hypoalpha subjects, compared to the normal controls, revealed that the reduced plasma levels of apoA-I were due to an increased apoA-I fractional catabolic rate, and that the synthetic rate was normal. Based on these results, we conclude that the apoA-I gene in these hypoalpha subjects is normal, and the PstI polymorphism near the apoA-I gene, which is associated with familial hypoalpha, is likely to be a marker for a mutant gene closely linked to, but not in, the apoA-I gene.     

Effect of Personality on Changes of Sleep Structure Caused by Emotional Stress

Effects of personality characteristics on the structure of sleep in ten normal subjects between the ages of 21–33 under stressors of various modalities were studied. Several psychological tests and polygraph recording of sleep during three nights (adaptation, background, and after emotional stress, which was modeled using the pretension level paradigm) were conducted. Statistical cluster analysis of the psychological test results revealed two groups of subjects. The first group predominantly used active coping mechanisms and was characterized by more pronounced alterations of sleep structure in response to adaptation stress (the first night in the laboratory). The second group used nonadaptation coping strategy. The sleep structure in these subjects more significantly changed in response to emotional stress.     

Muscular and intraocular pressure responses among ocular-hypertensive subjects: Is there a rationale for biofeedback?

Several animal and human investigations have indicated that intraocular pressure (IOP) levels may be associated with extreme drug-induced changes in the extraocular muscles. Further, recent data suggest that, among individuals with normal IOP level, moderate increases in facial muscle (EMG) activity around the eye while the eye is open are associated with increases in IOP. To investigate further the relationship between facial EMG activity and IOP levels and to examine a group of individuals with elevated IOP levels, subjects were recruited from outpatients at an optometry clinic. Three groups of subjects were selected: a group of ocular hypertensive subjects who showed elevated pressures at the optometry clinic and upon the day of testing, a group of labile ocular hypertensive subjects who evinced elevated pressures during their visit to the optometry clinic but lower pressures on the day of testing, and a group of normal IOP subjects who showed normal pressures both during their optometry clinic visit and on the day of testing. To investigate anxiety differences, subjects were administered the State-Trait Anxiety Inventory, but subsequent analysis revealed no group differences. To evaluate the role of stress upon muscle (EMG) functioning around the eye, subjects were subjected to imagery and standardized mental arithmetic stressors; analyses of these results also revealed no significant group differences. Finally, subjects were given EMG biofeedback for muscle activity around the eye while IOP was assessed during five alternating periods in which they made decreases and increases in EMG activity. Results revealed significant group, period, and group by period interaction effects. The pattern of results is interpreted as implicating EMG activity in IOP fluctuations; the implications of these data for potential biofeedback and stress management treatments are discussed.This research was supported by a Faculty Research Grant of the University of Alabama at Birmingham.     

Muscular and intraocular pressure responses among ocular-hypertensive subjects: is there a rationale for biofeedback?

Several animal and human investigations have indicated that intraocular pressure (IOP) levels may be associated with extreme drug-induced changes in the extraocular muscles. Further, recent data suggest that, among individuals with normal IOP level, moderate increases in facial muscle (EMG) activity around the eye while the eye is open are associated with increases in IOP. To investigate further the relationship between facial EMG activity and IOP levels and to examine a group of individuals with elevated IOP levels, subjects were recruited from outpatients at an optometry clinic. Three groups of subjects were selected: a group of ocular hypertensive subjects who showed elevated pressures at the optometry clinic and upon the day of testing, a group of labile ocular hypertensive subjects who evinced elevated pressures during their visit to the optometry clinic but lower pressures on the day of testing, and a group of normal IOP subjects who showed normal pressures both during their optometry clinic visit and on the day of testing. To investigate anxiety differences, subjects were administered the State-Trait Anxiety Inventory, but subsequent analysis revealed no group differences. To evaluate the role of stress upon muscle (EMG) functioning around the eye, subjects were subjected to imagery and standardized mental arithmetic stressors; analyses of these results also revealed no significant group differences. Finally, subjects were given EMG biofeedback for muscle activity around the eye while IOP was assessed during five alternating periods in which they made decreases and increases in EMG activity. Results revealed significant group, period, and group by period interaction effects. The pattern of results is interpreted as implicating EMG activity in IOP fluctuations; the implications of these data for potential biofeedback and stress management treatments are discussed.     

Effect of androgenic anabolic steroids on sperm quality and serum hormone levels in adult male bodybuilders

The purpose of this study was to assess the influence of the administration of high doses of androgenic anabolic steroids (AAS) on endocrine and semen parameters. Thirty volunteering bodybuilders were studied (ages ranging between 26.6 +/- 4.1 years). A history of anabolic steroid administration was recorded for fifteen subjects, and results of semen analysis and endocrine parameters were compared with data from fifteen bodybuilders not using steroids. In those subjects using AAS, eight had sperm counts under the lower normal limit (20 x 10(6) sperm/ml), three had azoospermia, two polyzoospermia, and two had normal sperm counts. The percentage of morphologically normal sperm was significantly reduced, only 17.7% had normal spermatozoa. In the control group, only one subject had oligozoospermia. The hormonal parameters revealed reduced FSH (1.5 +/- 3.2 vs 5.0 +/- 1.6, p < 0.001) and PRL (5.1 +/- 4.9 vs 9.2 +/- 4.4, p < 0.01) levels. LH, T, E2 and DHEA levels did not vary.     

Cytokinetic basis for the impaired activation of lymphocytes from patients with primary intracranial tumors

Patients with malignant brain tumors have a variety of immunologic abnormalities, including the impaired responsiveness of peripheral blood lymphocytes (PBL) to mitogens and alloantigens. We further investigated this impairment of lymphocyte reactivity by employing the techniques of limiting dilution analysis and cytokinetic analysis. PBL preparations from patients have approximately six times fewer phytohemagglutinin (PHA)-responsive cells than PBL from normal subjects. Similar results were obtained with purified T cell preparations. Cytokinetic analysis of PHA-induced [3H]thymidine incorporation employing colchicine blocking of mitosis demonstrated that the number of first generation cells entering the S-phase of mitosis for each 24-hr period was less for PBL from patients than for PBL from normal individuals. First generation responding cells from patients and normal subjects entered DNA synthesis at the same time (48 to 72 hr). Cytokinetic analysis over a period of 168 hr demonstrated that whereas PBL from normal individuals demonstrated second generation responding cells, PBL from the majority of patients did not, thus indicating a defect in their ability to undergo clonal expansion. Measurement of interleukin 2 (IL 2) activity in culture fluids from PHA-activated PBL from normal subjects and patients revealed significantly lower IL 2 levels in culture fluids from PBL from patients. The addition of various concentrations of lectin-free IL 2 to PBL from patients stimulated with PHA did not restore responsiveness to normal values. There was no difference between the levels of interleukin 1 (IL 1) produced by lipopolysaccharide-activated monocytes from normal subjects and patients. Overall, these results suggest that an intrinsic defect exists in T cells obtained from brain tumor patients that renders them unable to enter into normal mitogen-induced blastogenesis.     

基于Hyperion高光谱数据的城市植被胁迫评价

快速获取城市植被的胁迫状态,不仅对城市植被健康状况的维护,而且对城市生态环境的改善具有重要意义．在对受胁迫植被的生理特征和光谱特征进行分析的基础上,利用星载高光谱Hyperion数据,计算出与胁迫相关的14种高光谱植被指数,在此基础上运用BP神经网络算法建立了城市植被胁迫强度分类器,对城市植被的胁迫强度进行了识别与分析．结果表明：城市中心商住区的植被受胁迫程度明显高于城乡结合部和郊区;植被的受胁迫现象在大块绿地外围呈环状分布;构建的植被胁迫强度分类器能够较为准确地反映植被受胁迫的强度信息,可为大面积城市植被胁迫监测提供一种较为可靠而快捷的方法．     

Radioimmunoassay and chemical properties of glucose-6-phosphate dehydrogenase and of a specific NADP(H)-binding protein (FX) from human erythrocytes

Two sensitive radioimmunoassays, based on a double-antibody technique, were developed which allow detection of nanogram amounts of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and of a so far unknown NADP(H)-binding protein present in human erythrocytes (designated FX).The two proteins isolated in homogeneous form from human erythrocytes were iodinated with ¹²⁵I by means of lactoperoxidase. Antisera to both purified proteins were raised in rabbits and sequentially adsorbed on human erythrocytes and on human serum before use. No cross-reaction between the two proteins was apparent.Hemolysates from normal as well as from glucose-6-phosphate dehydrogenase-deficient subjects were investigated for their content in both immunoreactive proteins using the two radioimmunoassay methods. This preliminary study showed significantly lowered levels of immunoreactive glucose-6-phosphate dehydrogenase in erythrocytes from subjects carrying the Mediterranean variant of this enzyme (characterized by severe deficiency of catalytic activity), compared with normal subjects. This figure was reversed as concerns the content of immunoreactive FX which was found to be twice as high in glucose-6-phosphate dehydrogenase Mediterranean erythrocytes as in normal ones.The two purified proteins were submitted to a comparative analysis of their chemical properties including NH₂-terminal residues, CNBr peptides and tryptic fingerprints. These studies revealed significant differences in the primary structures of the two proteins and therefore tend to exclude FX'x being a discrete product arising from degradation of native glucose-6-phosphate dehydrogenase. Moreover, amino axid analysis and tryptic fingerprints indicated that FX, as well as glucose-6-phosphatase dehydrogenase, is composed of very similar and possibly identical polypeptide chains.     

A newly developed ELISA showing the effect of environmental stress on levels of hsp86 in Cherax quadricarinatus and Penaeus monodon

The induction of hsps by stress in Cherax quadricarinatus and Penaeus monodon was investigated using SDS-PAGE, Western blotting and ELISA techniques. Western blotting showed the presence of an immuno-reactive protein to mouse alpha-human hsp70 IgG1 monoclonal antibody at a mass of 86 kDa (hsp86) in pleopod samples but was not sensitive enough to detect differences in response to stress. An enzyme-linked immunosorbent assay (ELISA) was developed using this antibody for the detection of hsp86 in the pleopods of C. quadricarinatus and P. monodon. Using this assay, significantly higher levels of hsp86 were detected in hyperthermally stressed C. quadricarinatus (21 to 70 g) and P. monodon (14 to 32 g) and hypoosmotically stressed P. monodon (14 to 32 g). Male C. quadricarinatus and P. monodon were thermally stressed with an increase in temperature from 24 to 33 degrees C for a period of 2 h then a recovery period of 6 h. SDS-PAGE gels of thermally stressed C. quadricarinatus and P. monodon samples revealed an increase in protein band intensity at 97 kDa (C. quadricarinatus) and 43 and 35 kDa in P. monodon. A 25 kDa mass protein was induced in C. quadricarinatus when thermally stressed. P. monodon were osmotically stressed with a decrease from 31 to 15 ppt for 2 h with a recovery of 6 h. SDS-PAGE gels revealed increased intensity of bands at 35 and 43 kDa and a 100 kDa band was induced demonstrating a wide range response of protein profile to stress in these species. SDS-PAGE gels of both species investigated also revealed an apparent reduction in band intensity of the haemocyanin subunits in stressed samples. The ELISA described here constitutes the first quantitative assay for the detection of a hsp in crustaceans and the following investigations are believed to be the first to describe the response of hsps to stress in C. quadricarinatus and P. monodon. In doing so, they provide a sound basis for future studies of the role of hsps in physiological functions in commercially cultured crustaceans.     

Bile acid production in human subjects: rate of oxidation of [24,25-3H]cholesterol compared to fecal bile acid excretion

Bile acid production has been quantitated in seven subjects by methods that compare the results of two independent approaches, namely, quantitation of cholesterol side-chain oxidation and fecal bile acid excretion. Six hypertriglyceridemic (HT) subjects and one normolipidemic control were studied by both techniques. A further control subject was studied by the cholesterol side-chain oxidation method alone. Cholesterol side-chain oxidation was quantitated by measuring the appearance of 3H2O after intravenous administration of [24,25-3H]cholesterol, using multicompartmental analysis of plasma cholesterol and [3H]water specific activity. Body water kinetics were independently defined by use of oral D2O. Two HT subjects were restudied while they were taking cholestyramine, 16 g/day. In all ten studies, multicompartmental analysis closely simulated the observed appearance of 3H2O. Values obtained for bile acid production suggest that cholesterol oxidation, or bile acid input, was significantly greater than fecal bile acid output in the HT subjects (P less than 0.05). Cholesterol side-chain oxidation rates in the two normal subjects were lower than those encountered in HT subjects, being similar to published values for normal subjects both for bile acid synthesis as determined by isotope dilution kinetics and fecal bile acid excretion. Studies conducted with two, synthetically different, preparations of [24,25-3H]cholesterol indicated that, in one of the two preparations, approximately 20% of the tritium label was at positions proximal to C24. In the other preparation examined, all of the tritium was located at, or distal to, C24. Further studies revealed that 0.055-0.24% of the dose was present as labile tritium by virtue of its appearance as 3H2O following in vitro incubation with human plasma. Provided these isotope effects are taken into account, multicompartmental analysis of plasma [24,25-3H]cholesterol and body water appears to be a useful technique for quantitating cholesterol oxidation in human subjects.     

Serum and thyroid tissue lipids in patients with thyroid tumors in euthyroidism

Plasma lipids of 24 euthyroid subjects with thyroid adenoma and non-toxic primary differentiated thyroid carcinoma (papillary and follicular types) were assessed and compared with a similar investigation conducted on 20 normal subjects. A parallel study with thyroid tumor tissues examined the lipid changes which occurred in the same group of patients. These were compared with the picture seen in 5 normal thyroids. The investigations examined the changes in total lipids; total, free and esterified cholesterol; total phospholipids; lecithin; cephalin and sphingomyelin; triglycerides and free fatty acids in both serum and thyroid tissue. Compared with normal subjects, the serum lipids were almost identical except for the concentration of free fatty acids which showed significantly lower values in the group with neoplastic changes. Tissue analysis of the cancerous thyroid however revealed a marked rise in virtually all lipid fractions but the cholesterol seemed to dominate the picture. The differential studies of total phospholipids for thyroid tissue membrane lipids further revealed a significant increase in the lecithin and sphingomyelin components of total phospholipids as well as the esterified cholesterol fraction in thyroid carcinoma. The changes in thyrophospholipids were more marked in females normal thyroids than males. An attempt has been made through evaluation of the results derived from differential lipid studies to elucidate the role of some of the various fractions determined and the possible effect of the changes described on thyroid hormone metabolism.     

Glucose metabolism in the basal state and during a two-hour glucose infusion in low insulin responders and control subjects

Glucose metabolism was studied in eight low insulin responders to glucose and eight controls using a primed-constant tracer infusion technique. The tracer was 3-3H-glucose. The former group demonstrated a lower IVGTT than the controls, although the K-values were well within the normal range. They also attained higher blood glucose levels during iv administration of high and low glucose loads. Glucose turnover studies revealed normal hepatic glucose production, normal total glucose uptake and normal metabolic clearance of glucose in the low responders as a group. The findings suggest normal sensitivity to insulin in these subjects, and imply that the low insulin response is the sole mediator of the observed lowering in IVGTT.