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A miniaturized four-port polarization diversity ultra-wide band multiple input multiple output (MIMO) antenna is presented in this article. Different structures are combined and excited with the ta...

The study analyzes curriculum document (teacher course guides) of ADE and B.Ed. (Hons) programs in terms of Assessment Tasks, Teaching Learning Approaches, Course Outcomes and Course Description. Study also focuses on prospective teachers and teacher educator’s perceptions about these teacher course guides and their execution in class room at selected Teachers’ Training Institutes. The sample comprises three universities and four Regional Institutions of Teacher Education offering B.Ed. (Hons) and ADE programs. Researcher congregated data from 21 teacher educators teaching to prospective teachers enrolled in ADE and B.Ed. (Hons) in the chosen institutions. Mixed methods (approach) were used to collect quantitative as well as qualitative data for extensive analysis of the research problem. The qualitative data was collected through a check list and quantitative data was collected through questionnaire. The manuscripts (Draft guide for teaching instructor) for B.Ed. (Hons). Experts developed curriculum meets the requirement of the society of Pakistan with the purpose to create more competent, proficient and well-informed teaching instructors. Effective implementation of teacher guides need improvement in terms of availability of resources like well-equipped class rooms, computer lab, library, learning materials and Information and Communication Technology.

Bi 1.5 Zn 1.0 Nb 1.5 O 7 (BZN) thin films with thickness from 60 nm to 200 nm were prepared by radio-frequency magnetron sputtering and post-annealed from 550 °C to 650 °C. The x-ray diffraction results indicated that the BZN thin films possessed a cubic pyrochlore phase. The BZN thin films exhibited thickness-independent dielectric properties with dielectric constant of ~180 and low loss tangent less than 1% at 10 kHz as the film thickness decreased to 60 nm. The BZN thin films with thickness of 200 nm and post-annealed at 650 °C had a tunability of 32.7% at a DC bias field of 1.5 MV/cm. The results suggest that the BZN thin films have promising applications on the embedded capacitors, tunable devices and energy storage devices.

This paper describes a design of a circularly polarized patch antenna array for Ku-band (14.45 GHz - 15.65 GHz) data-link for small to medium unmanned aerial vehicles. A multilayer antenna structure including the feeding network is studied in this paper. Compact size, circular polarization and bandwidth are important requirements in designing this system. The required bandwidth and circular polarization are achieved by truncating the corners of patch elements using a power divider and four bent slots to reduce the coupling effects and maintain the polarization purity. The antenna array is analyzed in terms of return loss, radiation pattern, axial ratio and total gain over the complete frequency band.

The study analyzes curriculum document (teacher course guides) of ADE and B.Ed. (Hons) programs in terms of Assessment Tasks, Teaching Learning Approaches, Course Outcomes and Course Description. Study also focuses on prospective teachers and teacher educator’s perceptions about these teacher course guides and their execution in class room at selected Teachers’ Training Institutes. The sample comprises three universities and four Regional Institutions of Teacher Education offering B.Ed. (Hons) and ADE programs. Researcher congregated data from 21 teacher educators teaching to prospective teachers enrolled in ADE and B.Ed. (Hons) in the chosen institutions. Mixed methods (approach) were used to collect quantitative as well as qualitative data for extensive analysis of the research problem. The qualitative data was collected through a check list and quantitative data was collected through questionnaire. The manuscripts (Draft guide for teaching instructor) for B.Ed. (Hons). Experts developed curriculum meets the requirement of the society of Pakistan with the purpose to create more competent, proficient and well-informed teaching instructors. Effective implementation of teacher guides need improvement in terms of availability of resources like well-equipped class rooms, computer lab, library, learning materials and Information and Communication Technology.

Bismuth zinc niobate (BZN) thin films with excess Zn contents were deposited from the ceramic targets containing various excess amounts of ZnO (0–20 mol%) on Pt/TiO 2 /SiO 2 /Si substrate by RF magnetron sputtering at room temperature. As-deposited thin films were post-annealed at a temperature ≤200 °C, which is compatible with PCB substrates. The effect of Zn deficiency and Zn excess on the microstructure, dielectric, and electrical properties of BZN thin films was studied. As-deposited and post-annealed BZN thin films at a temperature ≤200 °C were amorphous in nature. An appropriate amount of excess zinc improves the dielectric and electrical properties of BZN thin films, while too much excess zinc leads to deteriorate the properties. BZN thin film with 5 mol% excess Zn content exhibits the maximum dielectric constant of 64 with a very low loss of 0.6%, measured at 10 kHz and the leakage current of less than 1 µA at an applied electric field of 200 kV/cm.

Self-adapting phased array antennas are designed to adapt to surfaces that change shape in time. This interesting feature allows to increase coverage of modern wireless devices, but on the other hand it raises the issue of maintaining the radiation pattern undistorted when the array changes its shape. Moreover nowadays many applications of phased arrays require beam steering capabilities, that is closely related to the possibility of tilting the main beam towards a desired direction (or away from an undesired one). In this work a 4 × 4 phased array antenna placed on a doubly wedge-deformed surface is considered: a simplified version of the projection method is adopted to recover its pattern when the main beam is tilted in multiple directions, thus leading to a simpler but still effective method.

The purpose of this draft is to introduce a compact CPW-fed antenna with WLAN band notched characteristics. For band notched characteristics, an inverted L-shaped structure is used on the surface of radiator. The proposed design has overall size of 25 × 25 × 1.6 mm3 and covers the entire UWB spectrum from 3.02 GHz to 11.34 GHz except the notch band from 4.9 GHz to 6.2 GHz. High concentration of surface current is shown on the inner side of antenna surface and inverted L-shaped stub, when the design is simulated at 5.5 GHz to show the band notch affect. The simulated results in terms of return loss, surface current distribution and VSWR exhibit good antenna performance over the complete spectrum. The validity of the proposed design is also shown by comparing the simulated results with the measured results.

Pattern recovering of conformai phased array on changing surfaces is receiving an increasing attention in the last years. This paper presents the pattern recovery of a strongly deformed conformal phased-array using the projection method. A 4 × 4 flat array is placed on a doubly curved surface. The phase compensation technique is applied first on rows, and then, considering rows as single antenna elements, on array columns. This technique demonstrates to be effective in recovering direction and width at half maximum of the pattern main lobe and in suppressing side lobes. Analytically predicted recovered patterns are confirmed through full-wave numerical simulations.

To compensate for bismuth loss that occurred during the film deposition process, Bi 1.5 Zn 1.0 Nb 1.5 O 7 (BZN) thin films were deposited at room temperature from the ceramic targets containing various excess amounts of bismuth (0–20 mol%) on Pt/TiO 2 /SiO 2 /Si substrates by using RF magnetron sputtering technique. The effect of bismuth excess content on the microstructure and electrical properties of BZN thin films was studied. The microstructure and chemical states of the thin films were studied by SEM and XPS. EPMA was employed to assess the film stoichiometry. The X-ray diffraction analysis reveals that the BZN thin films exhibit the amorphous structure in nature. An appropriate amount of excess bismuth improves the dielectric and electrical properties of BZN thin films, while too much excess bismuth leads to deterioration of the properties. BZN thin film with 5 mol% excess bismuth exhibits a dielectric constant of 61 with a loss of 0.4% at 10 kHz and leakage current of 7.26×10 −7 A/cm 2 at an electric field of 200 kV/cm.

This paper presents the comparison of two Ultrawideband (UWB) Multiple-Input-Multiple-Output (MIMO) antennas with different conductors. In the simulation two UWB-MIMO antennas with copper conductors and graphene-based conductors (GBC) are designed separately. The ground planes of both radiators are made of copper, only the top side is made with different conductors. A T-shaped decoupling structure is placed on the ground plane to reduce the coupling between the radiating patches. These two prototypes, one with copper conductors and the other one with GBCs are fabricated. A good agreement between the S-parameters of both prototypes is found. The measured radiation patterns of both prototypes also exhibit similar properties. Whereas, the GBC antenna showed a lower gain as compared to the copper antenna, as depicted in radiation patterns. However, impedance matching and the radiation characteristics of the GBC antenna also showed that graphene can be a good alternative to copper in UWB-MIMO conformal antennas.

Bi 2 Zn 2/3 Nb 4/3 O 7 thin films were deposited at room temperature on Pt/Ti/SiO 2 /Si(1 0 0) and polymer-based copper clad laminate (CCL) substrates by pulsed laser deposition. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films were deposited in situ with no intentional heating under an oxygen pressure of 4 Pa and then post-annealed at 150 °C for 20 min. It was found that the films are still amorphous in nature, which was confirmed by the XRD analysis. It has been shown that the surface roughness of the substrates has a significant influence on the electrical properties of the dielectric films, especially on the leakage current. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films deposited on Pt/Ti/SiO 2 /Si(1 0 0) substrates exhibit superior dielectric characteristics. The dielectric constant and loss tangent are 59.8 and 0.008 at 10 kHz, respectively. Leakage current density is 2.5 × 10 −7 A/cm 2 at an applied electric field of 400 kV/cm. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films deposited on CCL substrates exhibit the dielectric constant of 60 and loss tangent of 0.018, respectively. Leakage current density is less than 1 × 10 −6 A/cm 2 at 200 kV/cm.

Bi 2 Zn 2/3 Nb 4/3 O 7 thin films were deposited on Pt/TiO 2 /SiO 2 /Si(1 0 0) substrates at a room temperature under the oxygen pressure of 1–10 Pa by pulsed laser deposition. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films were then post-annealed below 200 °C in a rapid thermal process furnace in air for 20 min. The dielectric and leakage current properties of Bi 2 Zn 2/3 Nb 4/3 O 7 thin films are strongly influenced by the oxygen pressure during deposition and the post-annealing temperature. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films deposited under 1 Pa oxygen pressure and then post-annealed at a temperature of 150 °C show uniform surface morphologies. Dielectric constant and loss tangent are 57 and 0.005 at 10 kHz, respectively. The high resolution TEM image and the electron diffraction pattern show that nano crystallites exist in the amorphous thin film, which may be the origin of high dielectric constant in the Bi 2 Zn 2/3 Nb 4/3 O 7 thin films deposited at low temperatures. Moreover, Bi 2 Zn 2/3 Nb 4/3 O 7 thin film exhibits the excellent leakage current characteristics with a high breakdown strength and the leakage current density is approximately 1 × 10 −7 A/cm 2 at an applied bias field of 300 kV/cm. Bi 2 Zn 2/3 Nb 4/3 O 7 thin films are potential materials for embedded capacitor applications.

Balanced drilling through naturally fractured reservoir and controlling loss for preventing reservoir damage and rehabilitation of normal production is a serious challenge in the Kohat-Potwar basin of Pakistan. The potential of hydrocarbons in these reservoir rocks has been masked by the overbalance drilling practices in this region. Due to overbalance drilling in fractured reservoirs and the use of heavy mud with barite blocks the fractures and that results in little or no flow during DST. The negative results of DSTs usually force the decision makers either to abandon the well or to re-test and establish the connectivity between the formation and the well bore. The well under study was drilled in fractured carbonate reservoir rock to a depth of more than 5000 meters in Kohat–Potwar basin to target Datta and Lockhart formations. During drilling, due to complexities, well could not reach the Datta formation. No wire line and image logs could be obtained in Lockhart formation due to slim hole. The last 5-7/8 inch hole of this well had to be drilled by using Oil Based Mud (OBM) to control well bore instability, the same mud was used in the reservoir sections. During drilling, losses were observed in the reservoir section. On the basis of drilling information, the well was directly completed in the Lockhart formation. After completion, well was allowed to flow but no hydrocarbon surfaced. As Lockhart formation is proven producer, and it became a challenge to evaluate the reservoir for its production potential and to find out the causes of no flow from the formation. After negative results of well test, all the data of G & G and mud logging was reviewed and detailed analysis of fractures network over the field were carried out to understand the well behavior. The data revealed that mud losses during drilling are indicative of fracture's presence in the tested zone(s) and fractures may have been plugged resulting in no flow during test. It was realized that reservoir has potential but connectivity between formation and the well bore need to be enhanced. Even after no flow during initial testing of the well for long period, bold decision of cleaning of the well was under taken andseries of Nitrogen kick off jobs were undertaken to facilitate the well to flow. The nitrogen kick off werecontinued for four months, longest cleaning job ever undertaken in Pakistan and close monitoring of well was put inplace. After four months, WHFP started improving and flow of the hydrocarbons was observed and finally 730 bbl/d of oil and 1.6MMscfdgas were recorded. After the flow of the well, stimulation, with special recipe after lab experiments for OBM, wascarriedout with very encouraging results. After producing about one year, the well is still cleaning under natural flow. In this paper, we would try to share our experiences about the use of OBM in fractured carbonate reservoirs, fracture characterization, reservoir damage and its remedial jobs. In addition to this, well performance, well cleaning and stimulation methodology, evaluation of non-flow behavior of well during initial testing and the lessons learned to transform failure to success will be explained.

We have examined the carbohydrate composition of corticosteroid-binding globulin (CBG) obtained from rat and human serum. Rat CBG contained a carbohydrate composition that was strikingly different from that of human CBG. Like other glycoproteins that circulate in human plasma, human CBG had a carbohydrate composition that was consistent with the presence of biantennary and triantennary oligosaccharide structures. In contrast, the carbohydrate composition of rat CBG indicated the presence of more than one sialic acid residue per antenna. It is not clear whether rat CBG contains a carbohydrate structure with sialic acids attached to both galactose and N-acetylglucosamine on the same antenna, or a terminal disialylated structure (sialic acid linked alpha 2-8 to sialic acid). These structural variations may play a role in the interaction of CBG with its receptor.

Sex hormone-binding globulin (SHBG) is a plasma glycoprotein that binds a number of circulating steroid hormones (testosterone, dihydrotestosterone and estradiol) with high affinity, thus regulating their free concentration in plasma. In addition to binding steroids, SHBG itself binds to receptor sites on plasma membranes with somewhat unusual kinetics. Both the off and on rates are quite slow. The steroid-binding and membrane-binding functions are intertwined in what is clearly an allosteric relationship. Occupation of SHBG's steroid-binding site by a steroid inhibits its ability to bind to its membrane receptor-binding site. This inhibition is not related to a steroid's biological activity. Metabolites of steroids without biological activity, e.g. 2-methoxyestradiol, actively inhibit SHBG's interaction with its membrane receptor. However, if unliganded SHBG is allowed to bind to its receptor on intact cells, and an appropriate steroid hormone then is introduced, adenylate cyclase is activated and intracellular cAMP increases. This function is specific for steroids with biological activity, 2-methoxyestradiol has no activity in this arena. These observations demonstrate a potentially important role for SHBG as a regulator of cell function. They also demonstrate an additional mode of action of steroid hormones, one that does not require that the steroid interact with a steroid receptor.

The binding of human sex hormone-binding globulin (SHBG) to a human prostatic cancer cell line (LNCaP) and the results of that binding were examined. Membranes derived from LNCaP cells bound unliganded SHBG on two sets of sites whose affinities were: Ka1 = 3.1 +/- 1.6 x 10(10) M-1 and Ka2 = 8.7 +/- 4.3 x 10(6) M-1. Intact cells also bound SHBG, but even after 6 h, less than 10% of specifically bound SHBG was internalized. This observation speaks against a role for the membrane binding of SHBG in steroid transport across cell membranes. When LNCaP cells were prebound with SHBG, addition of dihydrotestosterone or estradiol resulted in a dose-dependent increase in intracellular cAMP. SHBG in the absence of steroids or dihydrotestosterone in the absence of SHBG was without effect. 2-Methoxyestradiol, a steroid metabolite without biological activity, but which binds to SHBG more tightly than does estradiol, was also without effect. These observations demonstrate a potentially important role for SHBG as a regulator of cell function. They also demonstrate an additional mode of action of steroid hormones, one that does not require that the steroid interact with a steroid receptor.

This investigation was undertaken to ascertain whether rat liver cells contained a receptor for corticosteroid-binding globulin (CBG) that could be differentiated clearly from the asialoglycoprotein receptor. To do this, [125I]CBG, [125I] asialo-CBG, and [125I]asialofetuin were used as probes to differentiate the binding activities of the two receptors. On hepatic membranes, CBG bound to a single set of sites with a Kd of 0.74 microM, asialofetuin bound to a single set of sites with a Kd of 0.018 microM, asialo-CBG bound to two sets of sites with Kd values of 0.004 and 1.4 microM and in the presence of 1 microM asialofetium, asialo-CBG bound to a single set of sites with a Kd of 0.53 microM, not different (P greater than 0.2) from the Kd of CBG. Cross-competition studies using the three 125I-labeled ligands and allowing each to compete with the three radioinert ligands indicated the existence of two separate receptors. Desialylation of hepatic membranes differentially affected the binding of CBG and asialofetuin. Finally, whole cells bound CBG specifically, but internalized it to only a minimal extent (less than 10%). This observation does not support a role for the CBG-receptor system in the entry of steroids into cells.

Fracture characterization is a biggest challenge for the geoscientists in sandstone and carbonate reservoirs. With the advancement of all technical capabilities in the acquisition of surface and subsurface Geological data, still it is extremely difficult to understand, characterize, and predict the distribution of fractures in a field. Image logs can successfully be used to locate and to provide directional trends of fractures near the wellbore. However, capturing all the fractures in one well and to predict their flow behavior can still be a challenge. In this paper, a case study of a fractured carbonate reservoir will be presented. The field is currently producing about 500 bbl of oil per day through fractures. Four wells have been drilled on the structure to drain the oil reserves. Water flooding is being carried-out in the field for the last 9 years for pressure maintenance and now 80 % water is being produced. The reservoir has very low primary porosity and permeability, and the flow is through fractures only. On the basis of the three wells fracture data, a new well was drilled, located ideally at a structurally higher position, in crestal area of the field. Image data showed abundance of fractures with different orientation was seen in the well bore but the well didn't flow and that led to its suspension. In this study, fracture data from image logs is compared with outcrop analogs and seismic reflection and interpretation data. In this paper, limitation of the available information, importance of understanding the stress regime, integration of G & G data and lesson learned from the current evaluation of the fracture system and their impact on development of field in Potwar basin will be presented.

We report a 2 1/2 years old female child who presented with Malignant Sacrococcygeal Yolk sac (Endodermal Sinus) tumor as presacral mass with ulceration of overlying skin. Her ultrasonography (USG)abdomen revealed a huge presecral mass with irregular margins extending in to the pelvis, pushing the rectum antero-laterally. CT scanning of abdomen confirmed USG finding with out enlargement of retroperitoneal lymph nodes and no involvement of the liver. Serum AFP was abnormally elevated. The tumor was excised along with Coccyx in-toto through posterior approach dividing the sacrum and 3-Drugs (VAC) Chemotherapy started postoperatively i.e. 2-weeks after surgery. Here we discuss our experience with this extremely rare malignant extra-gonadal germ-cell tumor and review of literature.

Sex hormone-binding globulin is a plasma glycoprotein that binds certain estrogens and androgens with high affinity. Over the past several years it has been shown that, in addition to functioning as a regulator of the free concentration of a number of steroid hormones, SHBG plays a central role in permitting certain steroid hormones to act without entering the cell. The system is complex. SHBG interacts with a specific, high affinity receptor (R(SHBG)) on cell membranes that appears to transduce its signal via a G protein. The SHBG-R(SHBG) complex causes the activation of adenylyl cyclase and the generation of cAMP within a matter of minutes after exposure to an appropriate steroid. Only steroids that bind to SHBG can activate SHBG-R(SHBG), but not all steroids that bind have this function, e.g. are agonists. All steroids that bind to SHBG but do not activate adenylyl cyclase are antagonists. The signals generated by the steroid-SHBG-R(SHBG) complex generate messages that have effects on the transcriptional activity of classic, intracellular receptors for steroid hormones. These and other downstream effects of this system are reviewed.

A knowledge, attitude and practice survey of acquired Immune Deficiency Syndrome (AIDS) was conducted among 805 paramedics at a tertiary care hospital in Islamabad in mid 1993. The mean age of the study population was 29.0 +/- 7.2 years and 59% were males. Almost 25% individuals either had no or upto primary level education. Initial response of 10% subjects was not having heard of AIDS and 70% thought their knowledge was sketchy, while 43% could not mention any cause for the disease. Almost 50% did not know that HIV infection could be asymptomatic. With respect to attitudes about AIDS, 30% subjects thought that changing life style shall have no effect on avoiding AIDS, 50% were of the view that at present AIDS did not pose a significant threat to them and 4% individuals however, admitted to having risk of contracting the disease. There existed significant gaps in the knowledge and attitudes of paramedical staff about AIDS and correlated with the level of education of the staff. These deficiencies need to be addressed through developing health education packages in local languages, targeted especially towards paramedical staff.

We have studied the concentration and properties of a protein which binds cortisol in human milk in samples obtained from women during the first 100 days after delivery. A filter disk assay was developed both for the measurement of plasma corticosteroid-binding globulin (CBG) and for the cortisol-binding protein in milk. The concentration of CBG in milk, expressed as its capacity to bind cortisol, is highest on the day of delivery, ca, 0.80 mug/dl, falls over the next 10 days to ca. 0.25 mug/dl, and remains at that level thereafter. If the concentration of CBG is expressed relative to the concentration of serum albumin in milk, it increases from day 1 to day 3 and then remains constant. A detailed comparison of CBG derived from milk and plasma showed that the two proteins co-migrated on Sephadex, sucrose gradient ultracentrifugation, and polyacrylamide gel electrophoresis. The two proteins had the same affinity for cotrisol, progesterone, 17-OH-progesterone, and dexamethasone. Furthermore, the binding activity of CBG in milk was neutralized with anti-CBG antibodies raised against CBG isolated from plasma. Unlike CBG, the concentration of cortisol in milk, 0.8-3.5 mug/dl, showed no systematic variation as a function of the postpartum day on which the sample was obtained.

Specific binding sites for corticosteroid-binding globulin (CBG) were detected on membranes prepared from rat spleen. The binding sites are typical of membrane receptors; they are saturable, specific, have high affinity, and require Mg2+ or Ca2+ for binding. There was little specific binding at 4 C, and maximal binding was obtained at 37 C. Scatchard analysis revealed a single set of binding sites with an apparent Kd of 0.84 microM, and a binding capacity of 39 pmol/mg membrane protein. The sites were specific for CBG; binding of [125I]CBG was not inhibited by a 10,000-fold excess of either rat albumin or rat transferrin. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate of the membrane-bound [125I]CBG revealed the presence of lower mol wt iodinated products which were undetectable in the unbound [125I]CBG fraction. Further, whereas the electrophoretic patterns from uterine, pulmonary, and renal membranes showed that the less mobile band (mol wt, 60K) of the normal CBG doublet appeared to be metabolized to a greater extent than the more mobile band (mol wt, 52K), those from splenic membranes showed equal metabolism of both parts of the doublet.

We isolated testosterone-estradiol-binding globulin TeBG rapidly and in high yield from pooled pregnancy plasma. It showed two bands on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE). Both bands stained with three different monoclonal antibodies to TeBG, thus demonstrating their immunological similarity. Freshly drawn, individual sera, from men, women, and pregnant patients were submitted to microaffinity chromatography, a procedure which partially purifies TeBG in approximately 4 hr. The partially purified plasma was submitted to SDS PAGE, followed by immunoblotting. The blotted TeBG exhibited the same two bands seen in the isolated, purified protein. The size heterogeneity observed in TeBG purified to: proteolysis occurring during isolation; a peculiarity of pregnancy plasma; or heterogeneity attendant upon the use of pooled plasma for isolation.

Because it no longer seemed reasonable to us that the sole function of the steroid-binding proteins in plasma was to serve as a buffer reservoir for steroid hormones, we conducted experiments which sought out other possibilities. Both CBG and SHBG bind to cell membranes, and this interaction partakes of the general characteristics of peptide hormone-membrane receptor systems. Additionally, human CBG has the ability to cause an increase in the activity of membrane-bound adenylate cyclase in MCF-7 cells, and this, in turn, results in an increase in cellular cAMP content. Thus, CBG appears to be a protein hormone. As a first consideration, one might presume that because CBG's half-life is measured in days, it would be counted among the hormones which, for the most part, are tonic in their effects, e.g., thyroid hormone. However, two important considerations tend to believe this presumption: (1) CBG which is unoccupied by steroid is not hormonally active (Figure 5): (2) Depending upon the time of day, circulating CBG is approximately 0-60% occupied in normal humans. These observations result in a circumstance in which a substantial portion of circulating CBG is available for activation by bursts of cortisol secretion. It seems prudent to speculate that, because steroids are essential for CBG's activity, the hormonal role of CBG may be entwined with, or complementary to the steroids which it binds. Finally, we should comment on the impact that our model of CBG as a hormone has on the view that only unbound steroid can be hormonally active. First, it should be stated that we have not addressed this question experimentally. Although there is evidence that CBG may be required for cortisol action, we feel that an obligate role for it is not documented adequately. At this time, we believe that CBG's hormonal role is compatible with a hypothesis that encompasses the view that unbound steroid hormones can diffuse into cells in some tissues and that both free and bound steroid can enter cells in others. Obviously, the final word on these important topics, as always, awaits the proper experiments.

• The iodinated antiarrhythmic drug amiodarone frequently causes an elevation of the serum thyroxine (T 4 ) level in patients who remain clinically euthyroid. Less frequently, true iodine-induced hyperthyroidism may occur. The clinical and laboratory distinction between these two conditions is often difficult. Since the serum sex hormone—binding globulin (SHBG) concentration is elevated in hyperthyroidism, this study was carried out to evaluate the serum SHBG concentration as a possible marker of hyperthyroidism in patients receiving amiodarone. Patients treated with amiodarone were divided into three groups: clinically euthyroid with normal serum T 4 and triiodothyronine (T 3 ) concentrations, clinically euthyroid with elevated serum T 4 and normal T 3 concentrations, and clinically hyperthyroid with elevated serum T 4 and T 3 concentrations. The mean serum SHBG concentration was significantly elevated in amiodarone-induced hyperthyroid patients, while it was normal in euthyroid patients treated with amiodarone who had normal or elevated serum T 4 concentrations. The results suggest that the hyperthyroxinemia induced by amiodarone is not associated with excess thyroid hormone action in the liver unless the serum T 3 concentration is also elevated. ( Arch Intern Med 1987;147:1781-1785)

We isolated testosterone-estradiol-binding globulin (TeBG) from human pregnancy plasma and used the isolated protein to obtain a rabbit antiserum to it. Using immunochemical techniques, the antiserum was demonstrated to be both monospecific and to have the ability to remove TeBG-binding activity from human serum. This antiserum was used to develop a RIA for human TeBG. The sensitivity is such that TeBG can be determined in as little as 0.005 microliter serum or plasma, although we routinely use 0.5-1.0 microliter. The correlation between the RIA and an established binding assay, using 63 different specimens, was 0.995.

We used immunological techniques to compare the serum corticosteroid-binding globulins (CBG) and testosterone-estradiol-binding globulins (TeBG) of Old World primates (man, chimpanzee, cynomologus, and rhesus), New World monkeys (squirrel and owl), and prosimians (galago and lemur). Four different antihuman TeBG antisera could not differentiate human and chimpanzee TeBG and recognized the galago and lemur TeBG as similar as well as the rhesus and cynomologus TeBG, as similar. Western blots of serum subjected to sodium dodecyl sulfate gel electrophoresis, with detection by an anti-TeBG antiserum, showed similar patterns of distribution of the two molecular species of TeBG for all of the New World primates and the owl monkey. The abundance of the two TeBG species was reversed in squirrel monkey serum, while lemur and galago displayed only a single band. Four different antihuman CBG antisera grouped together the CBGs of human and chimpanzee, rhesus and cynomologus, and lemur and galago. The squirrel monkey has a CBG with a markedly decreased affinity for cortisol; all four antisera perceived its CBG as much more immunologically distant from the human protein than that of the owl monkey. Indeed, three of the four antisera grouped squirrel monkey CBG with that of the prosimians, while one antiserum saw squirrel monkey CBG as even more distant from the human protein than the CBG of the primitive primates, the prosimians.

We examined the influence of numerous substances on the secretion of corticosteroid-binding globulin (CBG) and testosterone-estradiol binding globulin (TeBG) by a human hepatoma-derived cell line. Thyroxine, at physiologic concentrations, resulted in an increased secretion of TeBG but not CBG. Estrogens, antiestrogens, and androgens were without effect on either of these binding proteins.

Corticosteroid-Binding globulin (CBG) is a plasma protein that binds certain steroid hormones, mainly cortisol and progesterone. It has been demonstrated recently that specific binding sites for this protein exist on cell membranes. In this communication we establish that binding to these sites results in the induction of adenylate cyclase activity and the accumulation of cAMP in MCF-7 cells. These events are critically dependent upon a steroid being bound to CBG. These data are consistent with the hypothesis that CBG is a prohormone which is activated when cortisol is bound to it.