The role of allelic variation in estrogen receptor genes and major depression in the Nurses Health Study.

PURPOSE: The role of exogenous and endogenous sex hormones in the etiology of depression remains elusive, in part because sex hormone variation is often correlated with behaviors, life stage changes, and other factors that may influence depression. Estrogen receptor alpha (ESR1) and beta (ESR2) are known to regulate gene expression and estrogen response in areas of the brain associated with major depression and are unlikely to be correlated with exogenous factors that may influence depression. METHODS: We examined whether functional polymorphisms in these genes are associated with lifetime major depression and chronic major depression among a sample of women from the Nurses' Health Study II (N = 2527). DSM-IV depressive disorder symptoms were assessed by structured interview in 2007. Genotyping was performed on DNA extracted from blood using Taq-man. RESULTS: Women with the AA alleles of ESR2 RS4986938 had the higher prevalence of lifetime major depression than women with other allele frequencies (36.7 % for those with AA versus 28.5 % with GA and 29.1 % with GG, p = 0.02) and chronic major depression (14.7 % for those with AA versus 9.3 % with GA and 9.1 % with GG, p = 0.01). History of post-menopausal hormone (PMH) use modified the association of ESR1 polymorphism RS2234693 with any lifetime depression; specifically, those with the TT allele had the highest risk of lifetime depression among PMH users, and the lowest risk of depression among non-PMH users (p value for interaction = 0.02). Further, carriers of the AA alleles in ESR1 polymorphism RS9340799 had increased prevalence of lifetime major depression only among lifetime PMH users (p = 0.007). CONCLUSIONS: Our findings support the hypothesis that estrogen receptor polymorphisms influence risk for major depression; the role of estrogen receptors and other sex steroid-related genetic factors may provide unique insights into etiology.

Glycogen synthase kinase-3beta is a negative regulator of cardiomyocyte hypertrophy.

Hypertrophy is a basic cellular response to a variety of stressors and growth factors, and has been best characterized in myocytes. Pathologic hypertrophy of cardiac myocytes leads to heart failure, a major cause of death and disability in the developed world. Several cytosolic signaling pathways have been identified that transduce prohypertrophic signals, but to date, little work has focused on signaling pathways that might negatively regulate hypertrophy. Herein, we report that glycogen synthase kinase-3beta (GSK-3beta), a protein kinase previously implicated in processes as diverse as development and tumorigenesis, is inactivated by hypertrophic stimuli via a phosphoinositide 3-kinase-dependent protein kinase that phosphorylates GSK-3beta on ser 9. Using adenovirus-mediated gene transfer of GSK-3beta containing a ser 9 to alanine mutation, which prevents inactivation by hypertrophic stimuli, we demonstrate that inactivation of GSK-3beta is required for cardiomyocytes to undergo hypertrophy. Furthermore, our data suggest that GSK-3beta regulates the hypertrophic response, at least in part, by modulating the nuclear/cytoplasmic partitioning of a member of the nuclear factor of activated T cells family of transcription factors. The identification of GSK-3beta as a transducer of antihypertrophic signals suggests that novel therapeutic strategies to treat hypertrophic diseases of the heart could be designed that target components of the GSK-3 pathway.

Endobronchial stenting in the management of large airway pathology.

Endobronchial interventions including the deployment of endobronchial stents have a clear role in the management of central airway problems. The use of endobronchial stents has rapidly increased since the first airway stent was developed in the 1960s and with the subsequent manufacture of improved silicone and metallic stents. They provide effective relief for symptoms of intrinsic and extrinsic airway obstruction secondary to a wide range of pathologies including lung cancer, lymphoma, thyroid carcinoma and benign disease such as tracheal strictures and tracheobronchomalacia. Endobronchial stents can also seal defects within the airway including malignant broncho-oesophageal fistulae and posterior wall tracheal tears. They can be placed safely under conscious sedation at flexible bronchoscopy or under general anaesthetic at rigid bronchoscopy. Rigid bronchoscopy under general anaesthesia provided by a multidisciplinary team is safe with few contraindications. Complications of endobronchial stents include infection, granulation tissue formation and metallic stent fracture sometimes requiring removal, although serious life-threatening complications are very rare. Increasing numbers of patients are being referred to specialist centres for airway intervention. This article reviews the history of endobronchial stents, the different stents available, and the indications, outcomes and complications involved in deploying endobronchial stents.

The role of cAMP in the frequency-dependent changes in contraction of guinea-pig cardiomyocytes.

OBJECTIVES: beta-Receptor desensitisation, low basal cAMP, and a negative force-frequency relationship are characteristic changes in human heart failure. Isolated cardiomyocytes from noradrenaline-treated guinea pigs also show these features. We tested the hypothesis that low basal cAMP underlies the loss of contractile response to increasing stimulation frequency in this model. METHODS: Isolated cardiomyocytes were obtained from noradrenaline-treated (NA) and sham-operated (SHAM) guinea pigs. They were stimulated from 0.1-2 Hz and contraction amplitude was monitored with a video edge-detection system. RESULTS: NA cells had less positive amplitude-frequency responses (AFR) compared to SHAMs at 2 mM (P = 0.002, n = 17), or midrange Ca2+ concentrations (EC40-EC60) (P < 0.001, n = 13). When the cAMP agonist, 8-CPT-cAMP (CPT, 10 microM) or high Ca2+ (above EC75) was added to NA cells the AFR was normalised to that of SHAM myocytes (NA vs. SHAM P = ns). In control experiments the cAMP antagonists, Rp-cAMPS (Rpc) and Rp-8-CPT-cAMPS (Rp8, 100 microM), blocked the positive inotropic effects of CPT at 0.5 Hz (control pD2 = 4.36 +/- 0.06, Rp8 pD2 = 3.68 +/- 0.08, P < 0.0001), n = 6 paired). Rpc (100 microM) completely but reversibly blocked the effect of maximal isoprenaline in control experiments (P < 0.0001). Neither antagonist reduced the AFR compared to time-matched controls (P = ns, n = 6). Blockade of SERCA2a with thapsigargin resulted in a significant reduction in the AFR (ANOVA P < 0.0001). CONCLUSIONS: The results are consistent with sarcoplasmic reticulum (SR) function being a more important determinant of the amplitude-frequency relationship than tonic levels of cAMP under basal conditions. Reversal of AFR depression by CPT may result from stimulation of SR Ca2+ uptake.

Functional alterations in adult rat myocytes after overexpression of phospholamban with use of adenovirus.

An increased phospholamban (PLB)-to-sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) ratio has been suggested to contribute to the slowing of relaxation in failing human ventricle. We have used an adenoviral vector carrying the sequence for PLB to increase this ratio in isolated adult rat ventricular myocytes, and we have examined the functional consequences. With use of adenoviral vectors, the PLB content of adult rat myocytes was increased 2.73-fold, with SERCA2a levels unchanged. Maximum contraction amplitude of PLB-overexpressing myocytes was decreased to 6.9 +/- 0.3% shortening compared with 11.2 +/- 0.8% for 24-h controls (Con; P < 0.001, 5 preparations, 103 myocytes). Maximum rates of shortening and relengthening were also significantly decreased. Ca(2+) transient amplitudes were slightly depressed, and time to 50% decay of the transients was significantly increased: 237 +/- 18 (n = 14 myocytes) and 432 +/- 32 ms in Con and PLB (n = 15) myocytes, respectively (P < 0.001). The amount of Ca(2+) in the sarcoplasmic reticulum stores was reduced by 21% (P < 0.05). Relaxation was significantly slower in PLB than in Con myocytes when the Na(+)/Ca(2+) exchanger was blocked but not when sarcoplasmic reticulum Ca(2+) uptake was inhibited. Adenovirus infection with Ad.RSV.PLB was therefore able to produce functional changes in adult cardiac myocytes within 24 h, consistent with overexpression of PLB and similar to those seen in failing human heart.

A method of in vivo measurement of the elastic properties of skin in radiotherapy patients.

A portable apparatus which measures the force-displacement or elastic characteristics of skin in vivo has been constructed. A displacement transducer between two arms measures the extension of the skin as the arms are driven apart by means of a lead screw, and the force exerted on the skin is measured by means of two electrical resistance strain gauges attached at a reduced section on each of the arms. The apparatus was designed for compactness and lightness to enable it to be hand held. Illustrative results obtained on patients during and after courses of radiotherapy are presented.

The effect of Gi-protein inactivation on basal, and beta(1)- and beta(2)AR-stimulated contraction of myocytes from transgenic mice overexpressing the beta(2)-adrenoceptor.

The atria and ventricles of transgenic mice (TGbeta(2)) with cardiac overexpression of the human beta(2)-adrenoceptor (beta(2)AR) were initially reported to show maximum contractility in the absence of beta-AR stimulation. However, we have previously observed a different phenotype in these mice, with myocytes showing normal contractility but reduced betaAR responses. We have investigated the roles of cyclic AMP and Gi in basal and betaAR function in these myocytes. ICI 118,551 at inverse agonist concentrations decreased contraction by 32%. However, the cyclic AMP antagonist Rp-cAMPS had no effect on contraction in TGbeta(2) myocytes, indicating that there was no tonic influence of raised cyclic AMP. These findings cannot be explained by the proposed model for inverse agonism, where the activated receptor (R*) raises cyclic AMP levels and so increases contraction in the absence of agonist. After pertussis toxin (PTX) pretreatment to produce inactivation of Gi, the basal contraction in 1 mM Ca(2+) was increased in TGbeta(2) mice (7.82+/-0.47%, n=23) compared to LM mice (3.60+/-0.59%, n=11) (P<0.001). The contraction amplitude of myocytes to the maximal concentration of isoprenaline was also increased significantly by PTX in TGbeta(2) mice (9.40+/-1.22%, n=8) and was no longer reduced compared to LM mice (8.93+/-1.50%, n=11). Both beta(1)- and beta(2)AR subtypes were affected both by the original desensitization and by the resensitization with PTX. PTX treatment has therefore restored the original phenotype, with high basal contractility and little further effect of isoprenaline. We suggest that both beta-AR desensitization and lack of increased basal contraction in ventricular myocytes from our colony of TGbeta(2) mice were due to increased activity of PTX-sensitive G-proteins.

Characterization of bone materials as ultrasonic transducers.

Physical, dielectric, piezoelectric and electromechanical parameters have been reported for bone and its two major constituents i.e. collagen and apatite, for their characterization as ultrasonic transducer materials. Collagen and apatite have been extracted from full bone using well known methods. These materials have been used to prepare simple disc-shaped test pieces (dimensions: diameter 10 mm and thickness 1.0 +/- 0.01 mm). The variation of various electrical parameters with frequency in the region (1-108 MHz) is examined for these materials. These include impedance, phase angle, relative voltage output, quality factor 'Q', dielectric constant and resistivity. The data so obtained are compared with those for ceramic and quartz transducers. The observations on impedance, phase and relative voltage output for bone materials indicate that the first resonance peak falls around 56 MHz followed by second and third harmonics around 112 MHz and 168 MHz respectively. A low 'Q' value suggests a fairly wide band transducer, while other parameters compare favourably with ceramic and quartz materials. Bone material has also been used to obtain a transducer in the standard configuration and velocity dispersion in the frequency range 1-108 MHz is examined.

The effects of x-irradiation on the mechanical properties of skin.

The elastic properties of rat skin previously irradiated with single doses form 1000 to 3000 rad have been studied. The measurements were made 50 and 120 d after irradiation on skin specimens immersed in saline at 37 degrees c. The tests were carried out on a tensile testing machine. The load extension curve, which was plotted to the point of rupture, exhibits two portions which are identified with the aligment of the collagen fibres and then their subsequent stretching. The elastic properties associated with fibre alignment are little affected by these doses of radiation but the stiffness of the collagen itself tends to decrease with increasing dose, exhibiting a shoulder in the dose response curve.

The effects of split dose radiations on the mechanical properties of the skin.

A series of split dose experiments in which the interval between doses was varied from 1 to 7 d is reported. In vitro measurements of the mechanical properties of skin are made 50 and 120 d after the first irradiation. The variation of the skin thickness, load at rupture, extension at rupture, stress at rupture and skin stiffness with dose and with time interval between doses is examined. The results suggest that after the highest doses of irradiation the skin is matted in structure and the fractionation pattern is insignificant. Different fractionation patterns only influence the radiation effects at lower doses where the skin retains an open mesh structure. The experiments indicate that a maximum skin sparing effect is obtained with a two day interval between the split doses.

A comparison of different treatment regimes on the visual appearance and mechanical properties of mouse skin.

Four different regimes of radiotherapy employed in the treatment of basal cell epitheliomas were compared in order to assess their effect on the visual appearance and mechanical properties of skin. Three groups of mice received exposures identical to those given in the radiotherapy treatments; three months after completion of the radiation the visual and mechanical properties of the skin and its appendages were examined. The skin scarring, coat condition, greying of hair, skin, thickness, load at rupture, extension at rupture, mechanical stress at rupture and stiffness were used as cirteria for comparing the four treatments. The treatment regime which caused the least damage to normal skin was identified.

Effects of radiation on the visual appearance and mechanical properties of mouse skin.

A study of the long term effects of radiation on the visual appearance and mechanical properties of mouse skin is presented. The effects associated with the hair follicle (greying and alopecia) increase monotonically with exposure. Other effects (load, extension and stress at rupture and scarring of the skin) all show a reversal at the highest exposures. The skin thickness changes little with exposure, while the skin stiffness exhibits a shoulder on the response curve. Possible mechanisms underlying these effects are discussed.

Percutaneous laser disc decompression. A new therapeutic modality.

The authors present a new advance in the treatment of herniated disc disease using percutaneous Nd:YAG laser to vaporize a small portion of nucleus pulposus, thereby decompressing the disc. In vitro and in vivo animal data are presented. Three hundred seventy-seven magnetic resonance imaging or computed tomography scan-documented, herniated, nonsequestered lumbar intervertebral discs with corresponding clinical findings in 333 patients were so treated in an outpatient setting. The longest follow-up was 62 months, with a mean of 26 months. According to the Macnab criteria, there was a good to fair response in 261 patients (78.4%), and a poor response in 72 (21.6%); 166 patients experienced relief of pain during the procedure. One-third of repeat magnetic resonance imaging scans at 4-6 months postlaser treatment showed modest to moderate decrease of disc herniation.

Bioengineering in the millennium.

This symposium identified the major challenges in biomedical research that will benefit from bioengineering applications. Attention was focused on the important role that bioengineers will play in future advances in biomedical research. There was considerable discussion about how to integrate bioengineering with biological research in meeting the challenges of the twenty-first century. Symposium presenters showcased the accomplishments of NIH-funded bioengineering researches and increased the visibility of bioengineering to NIH leaders, staff, and members of the intramural and extramural research community. Recommendations were also made for future NIH-funded research projects. Attention was also placed on how basic bioengineering research can lead to commercialization of new health care technology and therefore maintain the nation's leadership in this important area. New products, from biotechnology and novel devices for diagnosis and treatment, are marketed through interactions between universities, medical centers, small start-up firms, and larger, more established companies. In the United States the gross revenue of the bioengineering private sector industry involved in the manufacture of health care products already exceeds $40 billion. More then 750 persons attended this bioengineering symposium. Over 110 scientific posters and exhibits relating to biology and medicine were presented. They provided a forum for showcasing NIH-funded bioengineering projects and fostered future collaboration among academic investigators, industry, and members of the small business community. The contributions of Pugwash bioengineer, Maciej Natecz, a member of the Polish Academy of Sciences, was recognized by the Conference Planning Committee. He was honored for his work in nuclear disarmament. Indian medical scientists should note that this symposium provided a framework for the development of technology in biomedical sciences during the Twenty-First Century. Major concentrations in interdisciplinary research should occur at all of the premier research institutions in India.

Effects of radiotherapy on the mechanical properties of human skin.

A portable apparatus that measures the elastic properties of human skin in vivo was used in a study involving 34 female patients being treated for carcinoma of the breast. Two skin areas were stretched: one at a site on the breast in the irradiated area and the other at a site on the nonirradiated contralateral breast. The mechanical tests on the skin were carried out before radiotherapy and then monthly after the treatment had ceased. It was found that the clinical and biological response of skin to radiation, particularly in fractionated treatments, depends on both the dose and the time. In particular, a three fractions a week treatment regime is preferable to five fractions a week.

Spectrophotometric analysis of cortical bone.

An attempt was made to study the structural behavior of a crystal in bone composite material of rats and rabbits. A Fourier transform infrared (FTIR) spectrophotometer and computer were used to monitor the infrared spectra of five bone samples each from the rats and rabbits. The spectra indicate the absorption band in the region of 500 to 700 cm(-1), with a wider bandwidth in the samples of rats as compared to rabbits. The spectra indicate that (1) the amorphous crystalline behavior of bone crystal is animal specific: (2) bone surface resorption is greater in amorphous bone; (3) cortical thickness may be affected by the bone's molecular structure; and (4) the mineral deposits on the collagen matrix are mediated through a biophysical mechanism that follows a crystallographical arrangement in the protein lattice.

On the classification of equine force traces.

Evidence indicating that comparison of a particular animal trace with a population average is an insufficient test of the health of a limb is presented. The methodology involves representing each of three recorded force components (vertical, lateral, and transverse) as a Fourier-Legendre series; the coefficients in the series represent the trace. A history for the horse is built by accumulating the coefficients (along with pertinent experimental data such as date, sex, weight, height, and in the case of race horses the date of last race) over a long duration. Then, on each subsequent recording, the trace is first compared with the animal's history to identify the occurrence of injury or pathology. If the limb is found to be normal, the trace is added to the history. Otherwise, it is recommended that the animal be further examined by a veterinarian. Preliminary results indicate that an animal trace needs to be compared with a history of traces for the same animal to identify alterations in the locomotive behavior of the limb.

Measurement of pressures in the nucleus and within the annulus of the human spinal disc: due to extreme loading.

Specially developed intervertebral and intradiscal pressure transducers are used to map the pressures in the nucleus pulposus and within the annulus fibrosus of the human spinal discs, to the point of fracture of the segmental units. The results show that for normal discs, pressures in the nucleus and in the annulus are linearly related to each other and to the applied compressive loads. Mechanical strains which develop around the periphery of the vertebral body are also linear with the applied compressive loads, when the partial vertebral column is loaded to the point of bony fracture. Failure of the intervertebral discs at the point of fracture occurred through the vertebral body endplates and the annulus fibrosus remained intact.

Bioengineering in the Millennium, National Institute of Health Symposium, Bioengineering: Building the Future of Biology and Medicine.

This symposium identified the major challenges in biomedical research that will benefit from bioengineering applications. Attention was focused on the important role that bioengineers will play in future advances in biomedical research. There was considerable discussion about how to integrate bioengineering with biological research in meeting the challenges of the twenty-first century. Symposium presenters showcased the accomplishments of NIH-funded bioengineering researches and increased the visibility of bioengineering to NIH leaders, staff and members of the intramural and extramural research community. Recommendations were also made for future NIH-funded research projects. Attention was also placed on how basic bioengineering research can lead to commercialization of new health care technology and therefore maintain the Nation's leadership in this important area. New products, from biotechnology and novel devices for diagnosis and treatment, are marketed through interactions between universities, medical centers, small start-up firms, and larger, more established companies. In the United States the gross revenue of the bioengineering private sector industry involved in the manufacture of health care products already exceeds $40 billion. More than 750 persons attended this bioengineering symposium. Over 110 scientific posters and exhibits relating to biology and medicine were presented. They provided a forum for showcasing NIH-funded bioengineering projects and fostered future collaboration among academic investigators, industry and members of the small business community. The role of bioengineering in the 21st century has already been highlighted by the author as far as research, education and space age technologies are concerned. The contributions of Pugwash bioengineer, Maciej Natecz, a member of the Polish Academy of Sciences, was recognized by the Conference Planning Committee. He was honoured for his work in nuclear disarmament.