532 nm green-light laser vaporization of upper tract urothelial carcinoma

Background

Endoscopic management of low risk upper tract urothelial carcinoma (UTUC) may be considered in select clinical scenarios, which allows sparing the morbidity of radical nephroureterectomy while achieving acceptable oncological outcomes and preservation of kidney function. Herein, we present a case with UTUC in a solitary kidney managed with 532 nm laser vaporization through a percutaneous approach.

Case presentation

The patient in this video (Additional file 1) is an 85-year-old woman who presented with a bulky tumor in the collecting system of a congenital solitary left kidney, which was a biopsy proven low grade urothelial carcinoma. Prior to the procedure, a lower pole percutaneous nephrostomy tube was successfully placed under sedation by Interventional Radiology. The procedure was done in a prone split leg position. The mass, which was predominantly localized to the renal pelvis was efficiently vaporized with the 532 nm laser in a systematic manner with continuous irrigation of normal saline through the cystoscope. The patient was discharged home on postoperative day 2 with the nephroureterostomy catheter open to drainage. This catheter was subsequently clamped and removed two weeks later without complications. Follow up uretroscopy showed excellent treatment response and the patient remains well without complications.

Conclusion

This case report details the potential utility of 532 nm laser vaporization of UTUC, however, ongoing studies are required to demonstrate peri-operative safety and durable oncologic efficacy.

Molecular mechanisms for leptin regulation of VEGF in breast cancer cells

Abstract #3071

Background: We have previously reported that in vitro and in vivo leptin signaling mediates proliferation of mouse 4T1 mammary tumor (MT) cells and levels of VEGF and VEGFR2. Therefore, we hypothesize that leptin can contribute to MT growth by augmenting angiogenesis through the regulation of VEGF expression. To test this we assessed whether leptin regulates VEGF promoter activity in mouse MT cells and if leptin-induced factors (HIF-1α, NFκB, AP1, SP1) regulate the VEGF promoter. Materials and Methods: Mouse MT cells (4T1, EM6 and MMT) were transiently transfected with molecular engineered luciferase-reporters (pGL3) for mouse VEGF promoter (full-length) and transcription factor-binding deletions for hypoxia responsive element (HRE), AP1, SP1 and NFκB. Leptin dose-response effects on reporter activity and VEGF levels (protein and mRNA) were investigated using ELISA, Western blot and real-time PCR, respectively. To further assess leptin regulation of VEGF expression in MT cells the effects of hypoxia (CoCl2, hypoxia mimetic agent) alone and combined with leptin on VEGF promoter activity were investigated. To assess which leptin-induced signaling pathways/transcription factors are linked to VEGF regulation in MT cells inhibitors for: (1) JAK2/STAT3, MEK-1/MAPK and PI-3K/Akt-1 pathways and; (2) target molecules NFκB; SP1; AP1 and HIF-1α were used. The effects of leptin/CoCl2 and inhibitors on luciferase activity of transfected cells were compared using pRL-TK renilla luciferase as control and the Dual-Luciferase Reporter Assay System. Results: Our data suggest that leptin signaling can regulate the transcriptional activity of VEGF gene in breast cancer cells by activating gene transcription at several sites of the VEGF promoter. Leptin-induced HIF-1α has a relevant role in the regulation of VEGF expression in MT cells. Leptin can also increase VEGF-levels (protein and mRNA) through the specific activation of AP1, SP1, and NFκB. PI-3K activity was mainly linked to leptin regulatory effects on VEGF. However, diverse mechanisms for leptin regulation of VEGF expression were found in the different MT cells. Discussion: Our results provide novel information on the molecular mechanisms for leptin-induced angiogenic effects in breast cancer. Our data further suggest that disruption of leptin signaling could impact angiogenesis and MT growth by inhibiting VEGF expression. Thus targeted disruption of leptin-signaling could serve as method of prevention/treatment of breast cancer. This work was supported in part by the Susan G. Komen Foundation for the Cure (to R.R.G.; BC 504370); UAB Breast SPORE Award (to R.R.G) and Contraceptive Research and Development Program (CONRAD; CIG-07-114 to R.R.G).

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3071.

Centrally Acting Imidazolines Stimulate Vascular Alpha 1A-Adrenergic Receptors in Rat-Tail Artery

: 1. Centrally acting imidazoline antihypertensive agents clonidine and moxonidine also act peripherally to contract blood vessels. While these agents act at both I(1)-imidazoline and alpha 2 adrenergic receptors centrally, the receptor types by which they mediate contraction require further definition. We therefore characterized the receptor subtype by which these agents mediate contraction of proximal rat-tail artery. 2. Dose-response curves were determined for phenylephrine and for several imidazoline ligands, using endothelium denuded, isolated ring segments, of tail arteries from adult male Sprague-Dawley rats. Ring segments were mounted on a force transducer with platinum wires and immersed in a tissue bath containing Krebs solution, to which drugs could be added. Signals were digitized and recorded by a computer. 3. Tail artery contractions expressed as a percent of contraction to 106 mM potassium were phenylephrine (96%), moxonidine (88%), clonidine (52%), and UK14304 (30%). Neither rilmenidine nor harmane caused contraction. Contraction of tail artery to moxonidine or clonidine could be blocked by alpha 1 antagonist urapidil or prazosin, and also by alpha 1A subtype selective antagonist WB4101. Schild plots were generated and a calculated pA2 value of 9.2 for prazosin in the presence of clonidine confirms clonidine as an agonist at alpha 1A receptors in proximal segments of rat-tail artery. 4. Our work suggests that clonidine and moxonidine are promiscuous compounds at micromolar concentrations and that harmane and rilmenidine are more selective compounds for in vivo imidazoline research.

Leptin serves as an upstream activator of an obligatory signaling cascade in the embryo-implantation process

Leptin is essential for mouse reproduction, but the exact roles it serves are yet to be determined. Treatment of cultured endometrial cells with leptin increases the level of beta3-integrin, IL-1, leukemia inhibitory factor, and their corresponding receptors. These leptin-induced effects are eliminated by inhibitors of leptin receptor (OB-R) signaling. Herein the impact of blocking leptin/OB-R signaling in the mouse endometrium was assessed. Intrauterine injection of either leptin peptide antagonists (LPA-1 or -2) or OB-R antibody on d 3 of pregnancy impaired mouse implantation in comparison to intrauterine injection of scrambled peptides (LPA-Sc) or species-matched IgGs. Significant reduction in the number of implantation sites and uterine horns with implanted embryos was found after intrauterine injection of LPA-1 (1 of 22) vs. LPA-1Sc (11 of 15) and LPA-2 (3 of 17) vs. LPA-2Sc (14 of 16). The impact of disruption of leptin signaling on the endometrial expression of several molecules in pregnant mice was assessed by Western blot, immunohistochemistry, and confocal microscopy. Disruption of leptin signaling resulted in a significant reduction of IL-1 receptor type I, leukemia inhibitory factor, vascular endothelial growth factor receptor 2, and beta3-integrin levels. The levels of colony stimulating factor-1 receptor and OB-R were unaltered after treatment with LPAs compared with controls. Expression of OB-R protein was pregnancy dependent and found only in glandular epithelium after implantation occurred. Our findings support previous observations that leptin signaling is critical to the implantation process and suggest that molecules downstream of leptin-activated receptor may serve obligatory roles in endometrial receptivity and successful implantation.

Leptin-induced increase in leukemia inhibitory factor and its receptor by human endometrium is partially mediated by interleukin 1 receptor signaling

Leptin and leukemia inhibitory factor (LIF) have been implicated as important mediators of implantation. The present study was designed to investigate whether leptin can directly regulate the expression of LIF and its receptor (LIF-R) in human endometrial cells and/or whether leptin-induced effects are linked to, or regulated in part by IL-1 signaling. Primary endometrial cells and endometrial epithelial cell lines (HES and Ishikawa cells) were cultured for 24-48 h in a medium containing insulin (5 microg/ml) and leptin (3, 10, and 62 nm) or IL-1beta (0.6, 3, and 10 nm) in the presence or absence of cytokines and/or receptor antagonists. The endpoints included phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the relative levels of LIF, LIF-R, IL-1beta, IL-1 receptor antagonist (IL-1Ra) and IL-1 receptor type I (IL-1R tI) as determined by ELISA or Western blotting techniques. Leptin treatment increases the level of phosphorylated STAT3, LIF-R, and LIF. Leptin also increases the levels of IL-1 ligand, receptor, and antagonist as was previously reported. Blockade of OB-R with antibodies or with a specific OB-R inhibitor (leptin peptide antagonist-2) abrogated leptin-induced effects, suggesting that leptin binding to its receptor activates Janus kinase 2/STAT3 signaling. Treatment of endometrial cells with IL-1beta also results in elevated levels of LIF-R. Interestingly, the inhibition of IL-1R tI with a specific antibody or with IL-1Ra negatively affects both leptin-induced and IL-1-induced effects on LIF-R levels. Abnormal endometrial LIF expression has been associated with human infertility and leptin has profound effects on the levels of LIF, IL-1, and their cognate receptors in vitro. Thus, it is tempting to speculate that leptin's role in vivo could include the regulation of other key cytokines to be fundamental to endometrial receptivity during implantation (i.e. LIF and IL-1).

Evaluation and refinement of the environmental stress index for different climatic conditions

The purpose of this study was to evaluate the recently constructed environmental stress index (ESI) for a large database comprising various climatic conditions. Data analysis of measurements from 19 locations revealed a high correlation between ESI and the wet bulb globe temperature (WBGT) index for each database. Validity from statistical analysis, including optimization procedures, slightly changed the ESI constants as follows: ESI = 0.62Ta - 0.007RH + 0.002SR + 0.0043(Ta x RH) - 0.078(0.1 + SR)(-1) where: Ta = ambient temperature (degrees C); RH = relative humidity (%); and SR = solar radiation (w x m(-2)). The refined ESI and the WBGT index were applied to databases of more than 125,000 measurements for each variable: Ta, RH, SR, black globe temperature (Tg), and wet bulb temperature (Tw). For each database, the ESI was then successfully correlated with the WBGT (P < 0.05, R2 > or = 0.899). We conclude that the refined ESI, which is constructed from fast response and commonly used weather sensors (Ta, RH, SR), is a potential index to serve as an alternative to the WBGT for heat category assessment.

Moxonidine, an Antihypertensive Agent, is Permissive to α1-Adrenergic Receptor Pathway in the Rat-Tail Artery

To investigate whether alpha1-adrenergic receptors were involved in the contractile response of tail arteries to moxonidine, isolated ring segments of tail arteries from male adult Sprague-Dawley rats were studied. Moxonidine (EC50 = 1.3 microM) and the alpha1-agonist phenylephrine (EC50 = 2.5 microM) increased tension development in the rat-tail artery similarly. The response to moxonidine (1 microM) could be blocked by both alpha1-adrenoceptor blockers prazosin (IC50 = 1 nM), and urapidil (IC50 = 14 nM), and also by alpha2-adrenoceptor blockers, yohimbine (IC50 = 49 nM) and efaroxan (IC50 = 49 nM). Combination drug treatment (urapidil and yohimbine, or yohimbine and prazosin) was more effective in blocking the contractile response to moxonidine, than treatment with prazosin or urapidil alone. Comparison of pA2 values for prazosin in the presence of moxonidine (9.35) or phenylephrine (10.2) confirm that alpha1-adrenergic receptors are involved in the contractile response of rat-tail artery to moxonidine.

Heart rate variability and electrocardiogram waveform as predictors of morbidity during hypothermia and rewarming in rats

This study examined electrocardiogram (ECG) waveform, heart rate (HR), mean blood pressure (BP), and HR variability as potential autonomic signatures of hypothermia and rewarming. Adult male Sprague-Dawley rats had telemetry transmitters surgically implanted, and 2 weeks were allowed for recovery prior to induction of hypothermia. Rats were lightly anesthetized (sodium pentobarbital, 35 mg/kg i.p.) and placed in a coil of copper tubing through which temperature-controlled water was circulated. Animals were cooled to a core temperature (Tc) of 20 degrees C, maintained there for 30 min, and then rewarmed. Data (Tc, BP, HR from ECG, and 10-s strips of ECG waveforms) were collected every 5 min throughout hypothermia and rewarming. Both HR and BP declined after initial increases with the drop in HR starting at a higher Tc than the drop in BP (29.6 +/- 2.4 degrees C vs. 27.1 +/- 3.3 degrees C, p < 0.05). Animals that were not successfully rewarmed exhibited a significant (p < 0.05) increase in the normalized standard deviation of interbeat intervals (IBI) throughout cooling compared with animals that were successfully rewarmed. The T wave of the ECG increased in amplitude and area with decreasing Tc. T-wave amplitude and IBI variability show potential as predictors of survival in hypothermic victims.

Effects of leptin, interleukin-1alpha, interleukin-6, and transforming growth factor-beta on markers of trophoblast invasive phenotype: integrins and metalloproteinases

Phenotypic changes of integrin and metalloproteinase secretion of the invasive human cytotrophoblast are regulated by cytokines and growth factors, but how this occurs is not completely understood. We used 24-h cytotrophoblast cultures from first trimester pregnancies to investigate the effects of leptin and cytokines on the expression of the alpha2, alpha5, and alpha6 integrin subunits and on the activity of metalloproteinase-2 (gelatinase A) and metalloproteinase-9 (gelatinase B). The alpha2 subunit was marginally upregulated by leptin and interleukin-1alpha (IL-1alpha). All compounds tested upregulated, in some degree, the alpha5 expression. The a6 integrin subunit was massively upregulated, by leptin, interleukins, and transforming growth factor-beta. None of the factors tested affected metalloproteinase-2 activity, but the activity of metalloproteinase-9 was upregulated by leptin and IL-1alpha. In conclusion, leptin and IL-1alpha actively induce some of the changes that cytotrophoblasts undergo to achieve a more invasive phenotype. A novel role for leptin is proposed during early pregnancy: leptin might be an autocrine/paracrine regulator of cytotrophoblast invasiveness during implantation and placentation.

Expression of steroidogenic acute regulatory protein in the human corpus luteum throughout the luteal phase

The expression of the steroidogenic acute regulatory protein (StAR) in the human corpus luteum (CL) was examined throughout the luteal phase. The primary 1.6-kb StAR transcript was in greater abundance in early (3.1-fold) and mid (2.2-fold) luteal phase CL compared with late luteal phase CL. The larger StAR transcript (4.4 kb) was found in early and midluteal phase CL, but was not detected in late luteal phase specimens. Mature StAR protein (30 kDa) was present in lower amounts within late CL compared with early and midluteal phase CL. The StAR preprotein (37 kDa) was also detected in greater abundance in early and midluteal CL. Immunohistochemistry revealed that StAR staining was most prominent in thecal-lutein cells throughout the luteal phase. The intensity of the signal for StAR exhibited significant changes throughout the luteal phase, being most intense during the midluteal phase and least during the late luteal phase. Plasma progesterone concentrations were highly correlated (r = 0.73 and r = 0.79) with luteal expression of the preprotein and mature StAR isoforms, respectively, throughout the luteal phase. To examine the LH dependency of StAR expression, the GnRH antagonist, Cetrorelix, was administered during the midluteal phase. Cetrorelix caused a decline in serum LH levels within 2 h, which, in turn, caused a pronounced decline in plasma progesterone within 6 h. The StAR 4.4-kb transcript was not detectable, and the 1.6-kb transcript was reduced by approximately 50% within 24 h of Cetrorelix treatment. The mature 30-kDa StAR protein level declined approximately 30% after Cetrorelix treatment. We conclude that 1) StAR mRNA and protein are highly expressed in early and midluteal phase CL; 2) StAR protein is present in both thecal-lutein and granulosa-lutein cells throughout the luteal phase; 3) StAR protein levels in the CL are highly correlated with plasma progesterone levels; 4) declining StAR mRNA and protein levels are characteristic of late luteal phase CL; and 5) suppression of LH levels during the midluteal phase results in a marked decline in plasma progesterone and a diminished abundance of StAR transcripts in the CL without a corresponding significant decline in StAR protein. Collectively, these data are consistent with the idea that StAR gene expression is a key determinant of luteal progesterone during the normal menstrual cycle. However, the pharmacologically induced withdrawal in the midluteal phase of LH support diminishes luteal progesterone output by mechanisms others than reduced StAR protein levels.

Leptin upregulates beta3-integrin expression and interleukin-1beta, upregulates leptin and leptin receptor expression in human endometrial epithelial cell cultures

Human endometrium and endometrial epithelial cells (EECs) either cultured alone or cocultured with human embryos express leptin and leptin receptor. This study compares the effect of leptin with that of interleukin-1beta (IL-1beta) on the expression of beta3-EEC integrin, a marker of endometrial receptivity. Both cytokines increased the expression of beta3-EEC at concentrations in the range of 0.06-3 nM; however, leptin exhibited a significantly greater effect than IL-1beta. We also determined the regulatory effects of IL-1beta on leptin secretion and on the expression of leptin and leptin receptor at the protein level in both EEC and endometrial stromal cell (ESC) cultures. In EEC cultures, IL-1beta upregulated secretion of leptin and expression of both leptin and leptin receptors. No effect of IL-1beta was found in the ESC cultures. However, leptin exhibited marginal upregulation of leptin receptor. The upregulation of beta3-integrin and leptin/leptin receptor expression by IL-1beta in EEC cultures indicates that both cytokines may be implicated in embryonic-maternal cross-talk during the early phase of human implantation. Our present data also raise the possibility that leptin is an endometrial molecular effector of IL-1beta action on beta3-integrin upregulation. Thus, a new role for leptin in human reproduction as an autocrine/paracrine regulator of endometrial receptivity is proposed.

Effects of leptin, interleukin-1alpha, interleukin-6, and transforming growth factor-beta on markers of trophoblast invasive phenotype: integrins and metalloproteinases

Phenotypic changes of integrin and metalloproteinase secretion of the invasive human cytotrophoblast are regulated by cytokines and growth factors, but how this occurs is not completely understood. We used 24-h cytotrophoblast cultures from first trimester pregnancies to investigate the effects of leptin and cytokines on the expression of the alpha2, alpha5, and alpha6 integrin subunits and on the activity of metalloproteinase-2 (gelatinase A) and metalloproteinase-9 (gelatinase B). The alpha2 subunit was marginally upregulated by leptin and interleukin-1alpha (IL-1alpha). All compounds tested upregulated, in some degree, the alpha5 expression. The a6 integrin subunit was massively upregulated, by leptin, interleukins, and transforming growth factor-beta. None of the factors tested affected metalloproteinase-2 activity, but the activity of metalloproteinase-9 was upregulated by leptin and IL-1alpha. In conclusion, leptin and IL-1alpha actively induce some of the changes that cytotrophoblasts undergo to achieve a more invasive phenotype. A novel role for leptin is proposed during early pregnancy: leptin might be an autocrine/paracrine regulator of cytotrophoblast invasiveness during implantation and placentation.

Abnormal pattern of integrin expression at the implantation window in endometrium from fertile women treated with clomiphene citrate and users of intrauterine device

Determine quantitative expression of endometrial integrins that reflect receptivity during implantation window in fertile women treated with clomiphene citrate (CC), and in intrauterine device users (IUD) as compared to fertile controls. Comparative study of the quantitative expression of a1, a4, av and b3 integrins in epithelial and stromal cells in mid-secretory endometrium of CC treated fertile women, IUD users and controls. All subjects included in this study had regular and ovulatory menstrual cycles.

SUBJECTS

Ten women treated with a daily dose of 50 mg of CC. Six women T-Cu device users and nine fertile controls. Age ranges for all groups were similar, 29-41 years old (mean 36.3). Tissue samples were taken at the mid-secretory phase or implantation window. A histological dating of the endometrial biopsies was assessed according to Noyes criteria. Ovulation was assessed by repeated transvaginal ultrasonography. The expression of a1, a4, aV and b3 integrins in dispersions of epithelial (EEC) and stromal (ESC) cells isolated from endometrial biopsies was quantitatively determined by flow cytometry using specific monoclonal antibodies. Immunohistochemistry was also used to detect integrin expression. Biopsies from CC-treated women had a high incidence of out-of-phase endometria. Interestingly, CC-treated women over-expressed a1, aV and b3-ESC integrins and under-expressed b3-EEC subunit (P<0.05). IUD users over-expressed the a1-EEC and under-expressed a4-ESC (P<0.05) at the time of the implantation window. CC treatment in fertile women provokes a high frequency of out-of-phase endometrium and desynchronises the expression of endometrial integrins at the implantation window. The epithelial b3 integrin was under-expressed in all CC-treated patients. The T-Cu intrauterine device alters endometrial receptivity by a different mechanism independent of the expression of the epithelial b3 integrin. However, both CC and IUD use alter the expression of some epithelial and stromal integrins during the implantation window.

Physiologic tolerance to uncompensable heat: intermittent exercise, field vs laboratory

PURPOSE

This study determined whether exercise (30 min)-rest (10 min) cycles alter physiologic tolerance to uncompensable heat stress (UCHS) when outdoors in the desert. In addition, the relationship between core temperature and exhaustion from heat strain previously established in laboratory studies was compared with field studies.

METHODS

Twelve men completed four trials: moderate intensity continuous exercise (MC), moderate intensity exercise with intermittent rest (MI), hard intensity continuous exercise (HC), and hard intensity exercise with intermittent rest (HI). UCHS was achieved by wearing protective clothing and exercising (estimated at 420 W or 610 W) outdoors in desert heat.

RESULTS

Heat Stress Index values were 200%, 181%, 417%, and 283% for MC, MI, HC, and HI, respectively. Exhaustion from heat strain occurred in 36 of 48 trials. Core temperatures at exhaustion averaged 38.6 +/- 0.5 degrees, 38.9 +/- 0.6 degrees, 38.9 +/- 0.7 degrees, and 39.0 +/- 0.7 degrees C for MC, MI, HC, and HI, respectively. Core temperature at exhaustion was not altered (P > 0.05) by exercise intensity or exercise-rest cycles and 50% of subjects incurred exhaustion at core temperature of 39.4 degrees C. These field data were compared with laboratory and field data collected over the past 35 years. Aggregate data for 747 laboratory and 131 field trials indicated that 50% of subjects incurred exhaustion at core temperatures of 38.6 degrees and 39.5 degrees C, respectively. When heat intolerant subjects (exhaustion < 38.3 degrees C core temperature) were removed from the analysis, subjects from laboratory studies (who underwent short-term acclimation) still demonstrated less (0.8 degrees C) physiological tolerance than those from field studies (who underwent long-term acclimatization).

CONCLUSION

Exercise-rest cycles did not alter physiologic tolerance to UCHS. In addition, subjects from field studies demonstrate greater physiologic tolerance than subjects from laboratory studies.

The effect of Portuguese Man-of-war (Physalia physalis) venom on calcium, sodium and potassium fluxes of cultured embryonic chick heart cells

Portuguese Man-of-war venom markedly increases calcium (45Ca2+) influx into primary, cultured, embryonic chick heart cells. This action is dose-dependent, but is unaffected by organic calcium blockers (diltiazem, verapamil, nifedipine, nimodipine and mibefradil). On the other hand, certain trivalent (La3+, Gd3+) and divalent (Zn2+, Ni2+, Cu2+, Mn2+) metals inhibit venom-induced calcium influx. Sodium (22Na+) influx into chick heart cells is also significantly increased by Man-of-war venom. Flecainide does not block venom-induced sodium influx. The efflux of the potassium analogue, 86Rb+, from heart cells is also significantly increased by the venom. The venom, however, has little or no effect on rubidium (86Rb+) or 2-deoxy-D-[2-3H] glucose influx.

Physiological problems associated with wearing NBC protective clothing during cold weather

This report considers how thermal balance of soldiers wearing nuclear, biological and chemical (NBC) protective clothing in combination with the Extreme Cold Weather Clothing System (ECWCS) is affected during work in cold weather. A review of published reports concerning physiological consequences of wearing NBC protective clothing during cold exposure was completed. The findings reported in the experimental literature were too limited to adequately forecast the effects of adding NBC clothing to ECWCS. To remedy the information gap, simulation modeling was employed to predict body temperature changes during alternating bouts of exercise and rest throughout 8 h of exposure to three different severely cold conditions. Published findings indicate that NBC protective clothing may inadequately protect against hand and finger cooling, especially during rest following strenuous activity. No evidence substantiates suggestions that wearing NBC protective masks increases susceptibility to facial frostbite. Collectively, the limited experimental work and the results of simulation modeling argue against any increased risk of hypothermia associated with wearing NBC protective clothing while working in the cold. However, wearing NBC protective clothing during strenuous activity in cold weather may increase the risk of hyperthermia, and cause sweat accumulation in clothing which may compromise insulation and increase the risk of hypothermia during subsequent periods of inactivity.

A quantitative evaluation of alpha1, alpha4, alphaV and beta3 endometrial integrins of fertile and unexplained infertile women during the menstrual cycle. A flow cytometric appraisal

The expression of integrin molecules alpha1beta1, alpha4beta1 and alphaVbeta3 within endometrial tissue has been proposed as a marker of uterine receptivity during the implantation window. The present investigation examines by flow cytometric analysis the concentrations of alpha1, alpha4, alphaV and beta3 integrin subunits in endometrial stromal (ESC) and epithelial cells (EEC) in two groups of women throughout the menstrual cycle: normal fertile women (n = 27) and women with unexplained infertility (n = 26). Integrin concentrations in endometrial cells were calculated in relative fluorescence units against a negative cellular control. The assessment of integrin subunits detected the protein in ESC and EEC from the late proliferative to the late secretory phase. In both groups of women, the alpha1 was the highest integrin expressed in ESC and EEC throughout the menstrual cycle. All women exhibited low concentrations of alpha4-EEC at the time of the implantation window. Infertile women expressed lower concentrations of the alpha4-ESC during the proliferative and early secretory phase while lower concentrations of the alpha1-ESC were seen during the late secretory phase. Interestingly, the infertile women expressed lower concentrations of beta3-EEC in the early, mid-secretory and late secretory phases (P < 0.05). Infertile women also expressed lower concentrations of alpha1-EEC and alphaV-EEC during the late secretory phase (P < 0.05). It can be concluded that the quantitative determination of beta3-EEC by flow cytometry confirmed its potential feature as a marker of endometrial receptivity at the time of the implantation window. In addition, the defective expression of the alpha1-ESC found in the late secretory phase might be associated with the poor fertility outcome of women with unexplained infertility.

Benefit of heat acclimation is limited by the evaporative potential when wearing chemical protective clothing

Heat acclimation-induced sweating responses have the potential of reducing heat strain for chemical protective garment wearers. However, this potential benefit is strongly affected by the properties of the garment. If the clothing ensemble permits sufficient evaporative heat dissipation, then heat acclimation becomes helpful in reducing heat strain. On the other hand, if the garment creates an impenetrable barrier to moisture, no benefit can be gained from heat acclimation as the additional sweating cannot be evaporated. Ten subjects were studied exercising on a treadmill while wearing two different chemical protective ensembles. Skin heat flux, skin temperature, core temperature, metabolic heat production and heart rate were measured. It was found that the benefit of heat acclimation is strongly dependent on the ability of the body to dissipate an adequate amount of heat evaporatively. The evaporative potential (EP), a measure of thermal insulation modified by moisture permeability, of the clothing ensemble offers a quantitative index useful to determine, a priori, whether heat acclimation would be helpful when wearing protective clothing system. The data show that when EP is < 15%, heat acclimation affords no benefit. An evaporative potential graph is created to aid in this determination.

Thermoregulatory responses to cold: effects of handwear with multi-layered clothing

BACKGROUND

Thermoregulatory responses were studied during rest and exercise in men wearing diverse handwear with an extended cold-weather clothing system [ECWCS]. The ECWCS (thermal insulation = 3.6 clo (1 clo = thermal resistance approximately 0.155 m2.K.W(-1)); weight = 10.1 kg) incorporates skin-tight polypropylene underwear, polyester/cotton fatigues, polyester-insulated liners, balaclava, vapor-barrier boots, and polytetrafluroethylene [PTFE]-lined outer garments.

METHODS

Six fit males each rested (M = 71 W.m(-2) and performed treadmill exercise (M = 171 W.m(-2)) while wearing the following handwear with the ECWCS: a light duty glove (LD, clo = 0.86), a heavy duty glove (HD, clo = 1.05), or an Arctic mitten (AM, clo = 1.46). Cold exposures were at Ta = 0 degrees C, -20 degrees C, and -30 degrees C; rh = 20%; wind speed = 10.34 m.s(-1). Exposure was a target period of 120 min designated as maximal endurance time (ET, min). All experiments were performed on separate days. Rectal (Tre), middle finger (Tmf), and mean weighted skin (Tsk) temperatures were recorded continuously; oxygen uptake and heart rate were measured periodically and total body weight loss msw, g.h(-1)) was determined after each run.

RESULTS

During rest at 0 degrees C, the ECWCS maintained Tre at 37 degrees C for the maximal ET with all handwear configurations; for each lower ambient condition, steady-state Tre dropped -0.2 degrees C per each 10 C decrease in Ta.Tmf at or near 5 degrees C prior to the maximal ET was the basis for premature attrition; Tsk of 29.4 degrees C was associated with subjective thermal discomfort. ET was predicted adequately by combining Tmf, heat production, Tre and Tsk.

CONCLUSIONS

The ECWCS with specific handwear furnish adequate ET in cold-dry ambients provided that ventilation and removal of extra layers is an option during heavy exercise and thermal insulation is not decreased by body moisture.

Evaluation of clothing systems to determine heat strain

This article describes the basic evaluation process and test methodology employed when temperature extremes for clothing systems must be considered as part of the U.S. Army's Health Hazard Assessment for material in the development and acquisition process. The goals of the evaluation are to select clothing systems that minimize the hazards of heat strain and to predict the heat strain for persons wearing such clothing. Clothing evaluations begin with biophysical assessments that determine the thermal characteristics (vapor permeability and insulation) for textiles via guarded hot plate tests and for clothing systems via thermal manikin tests. The results from biophysical tests can be used to select the textile and/or clothing with the best thermal characteristics. The data from manikin evaluations also can be used in prediction modeling. Human physiological testing is best done in a controlled laboratory environment, although for realism and user acceptability field trials may also be conducted. Proven test and measurement methods must be employed, and tests must control for confounding variables; subjects serve as their own controls, and test environment and procedures are consistent between trials. The process and test methodology described can be applied to the evaluation of civilian clothing systems as well as to the military systems for which they were developed.

Thermoregulatory responses to cold transients: effects of menstrual cycle in resting women

Effects of the menstrual cycle on heat loss and heat production (M) and core and skin temperature responses to cold were studied in six unacclimatized female nonsmokers (18-29 yr of age). Each woman, resting supine, was exposed to a cold transient (ambient temperature = mean radiant temperature = 20 to -5 degrees C at -0.32 degrees C/min, relative humidity = 50 +/- 2%, wind speed = 1 m/s) in the follicular (F) phase (days 2-6) and midluteal (L) phase (days 19-23) of her menstrual cycle. Clothed in each of two ensembles with different thermal resistances, women performed multiple experiments in the F and L phases. Thermal resistance was 0.2 and 0.4 m2 . K . W-1 for ensembles A and B, respectively. Esophageal temperature (Tes), mean weighted skin temperature (Tsk), finger temperature (Tfing), and area-weighted heat flux were recorded continuously. Rate of heat debt (-S) and integrated mean body temperature (Tb,i) were calculated by partitional calorimetry throughout the cold ramp. Extensive peripheral vasoconstriction in the F phase during early periods of the ramp elevated Tes above thermoneutral levels. Shivering thermogenesis (DeltaM = M - Mbasal, W /m2) was highly correlated with declines in Tsk and Tfing (P <0.0001). There was a reduced slope in M as a function of Tb,i in the L phase with ensembles A (P < 0.02) and B (P < 0.01). Heat flux was higher and -S was less in the L phases with ensemble A (P < 0.05). An analytic model revealed that Tsk and Tes contribute as additive inputs and Tfing has a multiplicative effect on the total control of DeltaM during cold transients (R2 = 0.9). Endogenous hormonal levels at each menstrual cycle phase, core temperature and Tsk inputs, vascular responses, and variations in body heat balance must be considered in quantifying thermoregulatory responses in women during cold stress.

Characterization of a three-phase response in gloved cold-stressed fingers

Seven gloves were studied worn by eight sedentary subjects (six men and two women) exposed to cold-dry, C D, (mean dry bulb temperature Tdb = -17.2 degrees C; mean dew point temperature Tdp = -25.1 degrees C), and cold-wet, C-W, (Tdh = 0 degrees C; Tdp = -8.4 degrees C) conditions. Mean endurance times were 75 min for the C-D and 162 min for the C W conditions. A three-phase response pattern of the temperature in the fingers was characterized. Phase I comprised an initial period during which finger temperature remained close to the pre-exposed level, due to delayed vasoconstriction in the finger. Phase II involved an exponential-like decrease of finger temperature indicative of the onset of vasoconstriction in the finger. Phase III manifested periodic finger temperature changes due to cold induced vasodilatation (CIVD). Mean wave patterns for phase III indicated approximately 3.5 waves x h(-1) in the C D but only about 2 waves x h(-1) in the C-W condition. Extension of endurance time, due to CIVD, was defined as the difference in time between the actual end of the experiment and the time the finger-tip would have reached the set temperature endurance limit as extrapolated by a continued exponential drop. Three overall response patterns of fingers in the cold were characterized: type A exhibiting all 3 phases; type B1 or B2 exhibiting either phases I+ II or phases II+ III; and type C showing only phase II. Considerable inter- and intra-subject variability was found. In both test conditions the final physiological thermal states of the subjects were between comfortable and slightly uncomfortable but acceptable and thus did not correlate with the responses in the fingers.

Simulation of a cold-stressed finger including the effects of wind, gloves, and cold-induced vasodilatation

The thermal response of fingers exposed to cold weather conditions has been simulated. Energy balance equations were formulated, in a former study, for the tissue layers and the arterial, venous, and capillary blood vessels. The equations were solved by a finite difference scheme using the Thomas algorithm and the method of alternating directions. At this stage of development the model does not include any autonomic control functions. Model simulations assumed an electrical heating element to be embedded in the glove layers applied on the finger. A 1.3 W power input was calculated for maintaining finger temperatures at their pre-cold exposure level in a 0 degree C environment. Alternate assumptions of nutritional (low) and basal (high) blood flows in the finger demonstrated the dominance of this factor in maintaining finger temperatures at comfortable levels. Simulated exposures to still and windy air, at 4.17 m/s (15 km/h), indicated the profound chilling effects of wind on fingers in cold environments. Finally, the effects of variable blood flow in the finger, known as "cold-induced vasodilatation," were also investigated. Blood flow variations were assumed to be represented by periodic, symmetric triangular waves allowing for gradual opening-closing cycles of blood supply to the tip of the finger. Results of this part of the simulation were compared with measured records of bare finger temperatures. Good conformity was obtained for a plausible pattern of change in blood flow, which was assumed to be provided in its entirety to the tip of the finger alone.

Body temperature and thermoregulation during submaximal exercise after 115-day spaceflight

BACKGROUND

Altered thermoregulation has been reported following spaceflight simulations (bed rest and water immersion) but has never been examined after actual spaceflight.

HYPOTHESIS

We tested the null hypothesis that body temperatures and heat loss responses during exercise would be similar before and after spaceflight.

METHODS

Two male crewmembers of the 115-d Mir 18 mission performed supine submaximal cycle exercise (20 min at 40% and 20 min at 65% of preflight VO2peak) once at 145-146 d preflight and once at 5 d postflight (R + 5).

RESULTS

After flight neither crewmember could complete the exercise protocol, stopping after 28-29 min. The core temperature (Tin, ingestible telemetry pill) at test termination was similar (37.8 degrees C for both subjects) pre- and postflight despite shorter postflight test duration. The slopes of the skin blood flow (laser Doppler)/Tin relationship (subject 1: 396 vs. 214; subject 2: 704 vs. 143% change Perfusion Unit/degree C), and the sweating rate (dew point hygrometry)/Tin relationship (subject 1: 6.3 vs. 2.0; subject 2: 4.6 vs. 0.7 mg.min-1.cm-2.degree C-1), were both reduced postflight without appreciable change in the Tin thresholds for sweating or skin blood flow.

CONCLUSION

In this preliminary report for two crewmembers, the sensitivity of the heat loss responses were reduced after long-duration spaceflight, resulting in a faster rate of rise in core temperature.

Heat strain models applicable for protective clothing systems: comparison of core temperature response

Core temperature (Tc) output comparisons were analyzed from thermal models applicable to persons wearing protective clothing. The two models evaluated were the United States (US) Army Research Institute of Environmental Medicine (USARIEM) heat strain experimental model and the United Kingdom (UK) Loughborough (LUT25) model. Data were derived from collaborative heat-acclimation studies conducted by three organizations and included an intermittent-work protocol (Canada) and a continuous-exercise/heat stress protocol (UK and US). Volunteers from the US and the UK were exposed to a standard exercise/heat stress protocol (ambient temperature 35 degrees C/50% relative humidity, wind speed 1 m/s, level treadmill speed 1.34 m/s). Canadian Forces volunteers did an intermittent-work protocol (15 min moderate work/15 min rest at ambient temperature of 40 degrees C/30% relative humidity, wind speed approximately 0.4 m/s). Each model reliably predicted Tc responses (within the margin of error determined by 1 root mean square deviation) during work in the heat with protective clothing. Models that are analytically similar to the classic Stolwijk-Hardy model serve as robust operational tools for prediction of physiological heat strain when modified to incorporate clothing heat-exchange factors.

Endothelium-dependent vascular smooth muscle relaxation activated by electrical field stimulation

Electrical field stimulation (EFS) produced relaxation of contracted arteries in the presence of tetrodotoxin. In the present study the contributions of vascular smooth muscle repolarization and endothelial release of nitric oxide to the relaxation response were investigated using isolated rat tail arteries and bovine aortic endothelial cells (BAEC). Intact and endothelium-denuded rings or intact, pressurized artery segments were contracted with either phenylephrine or KCl prior to EFS. Electrical field stimulation induced a small relaxation in denuded, phenylephrine contracted rings that was inhibited by the K+ channel blockers glibenclamide and BaCl2. In intact, phenylephrine-contracted rings, EFS induced significantly larger relaxations that were inhibited by BaCl2 as well as by L-NAME, an inhibitor of nitric oxide (NO) synthase, and methylene blue. EFS-induced relaxations were completely inhibited when BaCl2 and L-NAME or methylene blue were combined. Exposure to Ca(2+)-free buffer or diltiazem also inhibited the relaxation while ascorbic acid had no effect. Effluent from electrically stimulated BAEC caused denuded, phenylephrine contracted rings to relax. The ability of the effluent to cause relaxation was almost completely blocked by exposure of the BAEC to L-NAME or exposure of the recipient vascular smooth muscle to methylene blue; glibenclamide caused partial blockade. Simultaneous measurements of membrane potential and intraluminal pressure showed that EFS-induced membrane repolarization preceded changes in steady-state pressure. It is concluded that (1) the smooth muscle cells possess an endothelium-independent repolarization mechanism, (2) EFS causes endothelial cells of intact arteries to release NO and possibly a hyperpolarizing factor, (3) EFS of BAEC causes release of NO, and (4) EFS-induced relaxation depends on vascular smooth muscle cell membrane repolarization and endothelial cell release of vasoactive substances.

Numerical analysis of an extremity in a cold environment including countercurrent arterio-venous heat exchange

A model of the thermal behavior of an extremity, e.g., a finger, is presented. The model includes the effects of heat conduction, metabolic heat generation, heat transport by blood perfusion, heat exchange between the tissue and the large blood vessels, and arterio-venous heat exchange. Heat exchange with the environment through a layer of thermal insulation, depicting thermal handwear, is also considered. The tissue is subdivided into four concentric layers simulating, from the center outward, core, muscle, fat, and skin. Differential heat balance equations are formulated for the tissue and for the major artery and the major vein traversing the finger. These coupled equations are solved numerically by a finite-difference, alternating direction method employing a Thomas algorithm. The numerical scheme was extensively tested for its stability and convergence. This paper presents the model equations and results of the convergence tests, and shows plots of blood and tissue temperatures along the axis of the model for combinations of parameters including the effect of countercurrent heat exchange between the artery and the vein.

Applications of predictive environmental strain models

Researchers at the U.S. Army Research Institute of Environmental Medicine have developed and validated numerical models capable of predicting the extent of physiologic strain and adverse terrain and weather-related medical consequences of military operations in harsh environments. A descriptive historical account is provided that details how physiologic models for hot and cold weather exposure have been integrated into portable field advisory devices, computer-based meteorologic planning software, and combat-oriented simulation systems. It is important that medical officers be aware of the existence of these types of decision support tools so that they can assure that outputs are interpreted in a balanced and medically realistic manner. Additionally, these modeling applications may facilitate timely preventive medicine planning and efficient dissemination of appropriate measures to prevent weather- and altitude-related illnesses and performance decrements. Such environmental response modeling applications may therefore be utilized to support deployment preventive medicine planning by field medical officers.

Lumped-parameter tissue temperature-blood perfusion model of a cold-stressed fingertip

A lumped-parameter model of a fingertip is presented. The semispherical model includes the effects of heat storage, heat exchange with the environment, and heat transport by blood perfusion. The thermal insulation on the surface of the fingertip is represented by the overall heat transfer coefficient that is calculated by common engineering formulas. The model is solved analytically for the simple case of constant blood perfusion rate. The general case of variable blood perfusion rates is solved by an Euler finite difference technique. At this stage, the model does not include active control mechanisms of blood perfusion. Thus the effects of cold-induced vasodilatation have to be superimposed and are modeled by symmetrical triangular waveforms because these were found to best depict the behavior of fingers exposed to cold environments. Results of this model were compared with experimental data obtained in two separate studies. One included 60-min infrared thermograms of the dorsal surface of bare hands of sedentary subjects horizontally suspended on a fish net in a 0 degree C environment. Another study, on gloved finger temperatures, involved 0 and -6.7 degrees C environments. Fingertip (nail bed) temperatures of both these studies were compared with model predictions. Blood perfusion rates were assumed and adjusted within physiologically reasonable limits. Comparison of measured and computed temperature records showed very good conformity in both cases studied.

Predicting human heat strain and performance with application to space operations

This Institute has developed a USARIEM Heat Strain Prediction Model for predicting physiological responses and soldier performance in the heat, which has been programmed for use by hand-held calculators and personal computers, and incorporated into the development of a heat strain decision aid. This model is demonstrated to predict accurately (generally within +/- 1 SD/SEM) rectal temperature (Tre) responses for soldiers wearing various military clothing ensembles during U.S. or non-U.S. military scenarios in the heat at home or abroad. The value of this model is shown presently for three NASA scenarios involving the Launch and Entry Suit (LES). The LES (ventilated or unventilated) is modeled during pre-launch/launch, re-entry/landing, and emergency egress after re-entry/landing scenarios, predominately to evaluate heat acclimation and hydration state effects. During the pre-launch/launch scenario, predicted final Tre closely agrees with observed values suggesting minimal heat strain (Tre approximately 38.0 degrees C). In contrast, dehydrated (3%) unacclimated individuals show moderate levels of heat strain (Tre approximately 38.5 degrees C) for this same scenario. During the re-entry/landing and emergency egress scenarios, dehydrated unacclimated individuals are predicted to exhibit excessive heat strain (Tre > 39.0 degrees C). Thermal tolerance time is predicted to be only 6 min during emergency egress if individuals are dehydrated and unacclimated to heat while wearing the LES. If heat transfer values for space operations clothing are known, NASA can use this prediction model to help avoid undue heat strain involving astronauts for most scenarios during spaceflight.

Metabolic and thermal adaptations from endurance training in hot or cold water

Metabolic and thermal adaptations resulting from endurance training in hot vs. cold water were compared. It was hypothesized that training in hot water would have greater effects on muscle glycogen use and blood lactate accumulation during exercise than training in cold water. Eighteen men exercised at 60% of maximal oxygen uptake while immersed in hot (n = 9) or cold water (n = 9) for 1 h, 5 days/wk, for 8 wk. Training in hot water (35 degrees C) potentiated body temperature increases during exercise, and training in cold water (20 degrees C) blunted body temperature increases during exercise. Before and after training, cardiorespiratory and thermoregulatory responses and muscle glycogen and blood lactate changes were assessed during a 1-h exercise trial in hot water and, on a separate day using the same intensity, in cold water. Oxygen uptake was similar for all trials, averaging 2.0 +/- 0.1 l/min. It was observed that 1) training reduced glycogen use and lactate accumulation during exercise, with no difference between cold and hot water training groups in the magnitude of this effect; 2) lactate accumulation during exercise was the same in hot water as in cold water; and 3) skin temperature decreased more rapidly during cold-water exercise after than before training, with no difference between cold and hot water training groups in the magnitude of this effect. Thus, exercise-induced body temperature increases are not an important stimulus for glycogen-sparing effects and blunted lactate accumulation associated with endurance training.

Human thermoregulatory responses during heat exposure after artificially induced sunburn

Thermoregulatory responses in the heat (ambient temperature 49 degrees C, 20% relative humidity, 1 m/s wind) were investigated in 10 unacclimated men during 50 min of cycle ergometer exercise (approximately 53% of maximal aerobic power) after a 10-min rest before as well as 24 h and 1 wk after twice the minimal erythemal dose of UV-B radiation that covered approximately 85% of the body surface area. In 7 subjects esophageal temperature (Tes) was recorded while in all 10 subjects five-site skin and rectal temperatures, heart rate, and back, left forearm, and shielded (12 cm2 area) right forearm sweating rates (msw) were recorded at 15-s intervals. Venous blood was collected before and after exercise-heat stress. Mean skin temperature, Tes, rectal temperature, heart rate, and total body sweating rate were not significantly (P greater than 0.05) affected by sunburn. Pre- and postexercise values of hematocrit, hemoglobin, plasma protein, plasma volume, and plasma osmolality were also not affected (P greater than 0.05) by sunburn. Analysis of presunburn and post-sunburn data showed that the Tes intercept for sweating (degrees C) was unaffected (P greater than 0.05), but msw/Tes and final msw from the left forearm (msw/Tes 0.24 +/- 0.02 vs. 0.17 +/- 0.01 mg.cm-2.min-1. degrees C-1, P less than 0.05; msw 0.60 +/- 0.05 vs. 0.37 +/- 0.02, mg.cm-2.min-1, P less than 0.05) and back (msw/Tes 0.43 +/- 0.03 vs. 0.36 +/- 0.01 mg.cm-2.min-1. degrees C-1, P = 0.052; msw 1.08 +/- 0.09 vs. 0.74 +/- 0.05 mg.cm-2.min-1, P less than 0.05) were significantly reduced 24 h postsunburn.(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological consequences of intermittent exercise during compensable and uncompensable heat stress

Time-weighted averaging is a traditional method used in heat stress analyses to approximate, in terms of a single continuous level of heat production, the rate of heat production from complex intermittent exercise patterns. Physiological responses during intermittent and continuous exercise were studied in four subjects exposed to heat stress in which evaporation was either free or severely restricted. Intermittent work consisted of repeated 10-min exercise-rest patterns. Continuous work was at the time-weighted average of intermittent exercise: 3.3 mets. When heat stress was uncompensable, intermittent work induced more physiological strain than continuous work: endurance time was 14 min less (P less than 0.05); core temperature at 60 min was 0.40 degrees C higher (P less than 0.05); and, after 30 min of exposure, the rate of core temperature rise was 33% greater. The difference in the rate of heat storage was not satisfactorily explained by a discrepancy in the average rate of heat production or in the calculated rate of surface heat loss. Alternatively, the results may be partially explained by interruptions in the usual rate of heat transport via the cutaneous circulation. These interruptions may be caused by nonthermal factors associated with postural and work load transitions. Although the mechanisms are not totally understood, it is clear that application of the time-weighted averaging method can lead to erroneous overprediction of endurance time and should be applied with discretion.

Quantification of conservative endurance times in thermally insulated cold-stressed digits

The estimation of endurance times of the digits exposed to cold weather is performed by an analytical, one-dimensional cylindrical model. Blood perfusion effects are lumped into a volumetric heat-generation term. Cold-induced vasodilatation (CIVD) effects are not included in the present analysis. Endurance times, defined by a drop in cylinder tip temperature to 5 degrees C, were evaluated. Parameters included in this evaluation were 1) environmental temperatures, 2) thermal insulation applied on the cylinder, 3) length of the cylinder, and 4) diameter of the cylinder. It was found that the lower the ambient temperature, the longer the finger, and the smaller its diameter, then the shorter the endurance time for the same thermal insulation. Results of the model were compared with measured data for a subject not exhibiting CIVD response to cold stress. Conformity of results calculated for an adjusted value of the volumetric heat-generation term and measured data was very good, with a maximum deviation of less than 10% at only one particular point in time. This model facilitates the conservative estimation of lower bounds to thermally insulated fingers and toes exposed to cold stress.

An enzyme immunoassay for determining total thyroxine in human serum using an ultramicroanalytical system

A simple, rapid competitive ultramicroElisa assay has been developed for the measurement of total thyroxine (T4) using only 10 microliters of serum. Our novel UME is based on fluorescence measurements of the hydrolytic product of 4-methyl-umbelliferyl-beta-D-galactopyranoside. T4-beta-Galactosidase conjugates and monoclonal antibodies were immobilized on polyvinyl plates, with sodium salicylate used as a blocking agent for thyroxine binding protein. The analytical steps were carried out using a semiautomated batch-assay system entitled "SUMA" (system for ultramicroanalysis). The T4 assay was completed in 2 h, with a measuring range of 24-386 nmol/L. The intra-assay coefficient of variation (CV) was 4.6-6.9% and the inter-assay C.V. 9.0-12.4% depending on the T4 concentrations. Percentage recovery ranged from 99.2-111%. Regression analysis showed a good correlation with an established radioimmunoassay (n = 121, r = 0.946, P less than 0.01).

Color modulation of Doppler spectra with the use of a personal computer

This paper describes a method for the use of a personal computer in developing color modulated spectral maps of blood flow echoes from a Doppler flowmeter. The acoustical signal from a Doppler flowmeter is digitized and transformed into the frequency domain with a fast Fourier technique with the use of an Apple IIe microcomputer in conjunction with a Motorola 68000 co-processor. The resultant transform is displayed as a pseudo three-dimensional, color modulated spectral map by way of a color monitor, or a television projector onto the meeting room screen. We have found this technique to be useful in appreciating differences in blood flow from different hydraulic conditions, as well as in helping the medical students appreciate these differences in pulsatile flow in various arteries.

Direct solid-phase time-resolved fluoroimmunoassay of 17 alpha-hydroxyprogesterone in serum and dried blood spots on filter paper

We describe a direct, solid-phase time-resolved fluoroimmunoassay (TRFIA) for measuring 17 alpha-hydroxyprogesterone (17OHP) in serum and blood spots on filter paper. We used 17OHP-3-carboxymethyloxime (17OHP3CMO) coupled to polylysine as the label, which enabled incorporation of up to 34 atoms of europium per molecule of 17OHP, for a very high specific activity. The assay is based on competition between labeled 17OHP3CMO and 17OHP in blood specimens for polyclonal rabbit anti-17OHP antibodies. The antibody-label complex is separated by binding to anti-rabbit antibodies coated onto microtiter strips. The assay buffer contains danazol to displace 17OHP from steroid-binding proteins in serum. For serum samples, the assay is accomplished in 1 h of incubation at room temperature. The blood spot assay with filter paper discs involves incubation overnight at 4 degrees C. Results for both types of specimens from the same subjects correlated well. The lowest measurable concentrations of 17OHP (nmol/L) were 0.10 (3 SD) and 0.75 (3 SD) for serum and dried blood on filter paper, respectively. Intra- and interassay CVs were about 5-15% for both types of samples.

Direct solid-phase time-resolved fluoroimmunoassay of 17 alpha-hydroxyprogesterone in serum and dried blood spots on filter paper

We describe a direct, solid-phase time-resolved fluoroimmunoassay (TRFIA) for measuring 17 alpha-hydroxyprogesterone (17OHP) in serum and blood spots on filter paper. We used 17OHP-3-carboxymethyloxime (17OHP3CMO) coupled to polylysine as the label, which enabled incorporation of up to 34 atoms of europium per molecule of 17OHP, for a very high specific activity. The assay is based on competition between labeled 17OHP3CMO and 17OHP in blood specimens for polyclonal rabbit anti-17OHP antibodies. The antibody-label complex is separated by binding to anti-rabbit antibodies coated onto microtiter strips. The assay buffer contains danazol to displace 17OHP from steroid-binding proteins in serum. For serum samples, the assay is accomplished in 1 h of incubation at room temperature. The blood spot assay with filter paper discs involves incubation overnight at 4 degrees C. Results for both types of specimens from the same subjects correlated well. The lowest measurable concentrations of 17OHP (nmol/L) were 0.10 (3 SD) and 0.75 (3 SD) for serum and dried blood on filter paper, respectively. Intra- and interassay CVs were about 5-15% for both types of samples.

Control of thermoregulatory sweating during exercise in the heat

The purposes of this study were the following: 1) to determine whether erythrocyte infusion alters the control of thermoregulatory sweating and 2) to demonstrate how increases and decreases of both plasma tonicity and blood volume influence the thermoregulatory control parameters of threshold temperature and sweating sensitivity. Six non-heat-acclimated and five heat-acclimated males attempted heat stress tests (HSTs) both before and shortly after (48-96 h) autologous erythrocyte infusion. The non-heat-acclimated subjects were euhydrated for both HSTs, whereas the heat-acclimated subjects were studied in a euhydrated and a hypohydrated (-5% body wt) condition both pre- and postinfusion (500 ml of solution containing approximately 60% hematocrit of autologous erythrocytes). The HSTs consisted of treadmill exercise (335 W.m-2) in a hot (35 degrees C, 45% relative humidity) environment, and esophageal temperature and local sweating rate were continuously measured during 25 min of exercise. These experiments resulted in a matrix of conditions where both plasma tonicity and blood volume were increased or decreased relative to control conditions (euhydration, preinfusion). The findings concerning thermoregulatory sweating during exercise in the heat were summarized as follows: 1) acute polycythemia decreases the threshold temperature and increases the sweating sensitivity, 2) both threshold temperature and sweating sensitivity are increased or decreased from control levels dependent on the combined influence of plasma tonicity and blood volume, and 3) equations are presented that describe how plasma tonicity and blood volume alter threshold temperature and sweating sensitivity values.

Human intravascular immunoglobulin responses to exercise-heat and hypohydration

Several investigators have suggested that prolonged exercise and hypohydration alter the intravascular mass of immunoglobulins. Those studies, however, have methodological concerns which make generalizations from their data very tenuous. This study examined the effects of prolonged moderate intensity exercise in the heat and hypohydration on changes in the intravascular mass of immunoglobulins. Five heat-acclimated males attempted two Heat Stress Tests (HSTs). One HST was completed when subjects were euhydrated and the other HST when subjects were hypohydrated (-5% from base line body weight). The HSTs consisted of 30 min of rest in a 20 degrees C antechamber, followed by a 120-min exposure (2 repeats of 15 min rest and 45 min walking) in a hot (35 degrees C, 45% rh) environment. The following observations were made concerning immunoglobulin responses to hypohydration and exercise-heat stress: a) the changes in concentrations (mg.dl-1) of the measured immunoglobulins were often a reflection of changes in the plasma volume; b) hypohydration increased the intravascular mass (g) of the complement enzyme C3 during resting conditions, but did not alter the intravascular mass of IgG, IgA, and IgM, and c) prolonged treadmill exercise in the heat, when either euhydrated or hypohydrated, did not alter the intravascular mass of IgG, IgA, IgM, and C3. These data indicate that the intravascular mass of immunoglobulins does not change during prolonged moderate intensity exercise in the heat, and that hypohydration results in a translocation of C3 to the intravascular space. In addition, these data indicate that immunoglobulins do not provide a stress index for hypohydration.

Circadian variations in plasma renin activity, catecholamines and aldosterone during exercise in women

Four women were studied at 0400 h and 1600 h to determine if their hormonal and hemodynamic responses to exercise varied with the circadian cycle. Esophageal temperature was measured during rest and exercise (60% peak VO2; 30 min) in a warm room (Ta = 35 degrees C; PH2O = 1.7 kPa). Venous blood samples were drawn during rest and exercise and hemoglobin concentration (Hb), hematocrit (Hct), plasma osmolality (Posm), plasma protein concentration (Pp), colloid osmotic pressure (COP), plasma renin activity (PRA), cortisol, aldosterone, norepinephrine (NE) and epinephrine (E) were determined. Changes in plasma volume (PV) were estimated from changes in Hb and Hct. The relative hemoconcentration (-11.2%) was similar at 0400 h and 1600 h, but the absolute PV was smaller at 1600 h than at 0400 h (p = 0.03). The responses of Posm, Pp and COP to exercise were unaffected by time of day. Although PRA was not different at the two times of day, PRA was 244% greater during exercise at 1600 h, but only 103% greater during exercise at 0400 h. The normal circadian rhythms in plasma aldosterone (p = 0.043) and plasma cortisol (p = 0.004) were observed. Plasma aldosterone was 57% greater during exercise, while plasma cortisol did not change. The change in E and NE was greater at 0400 h, but this was due to the lower resting values of the catecholamines at 0400 h. These data indicate that time of day generally did not affect the hormonal or hemodynamic responses to exercise, with the exception that PRA was markedly higher during exercise at 1600 h compared to 0400 h.

Polycythemia and hydration: effects on thermoregulation and blood volume during exercise-heat stress

We studied the effects of autologous erythrocyte infusion on thermoregulation and blood volume during exercise in the heat. Specifically, we wanted to determine whether heat-acclimated subjects, as well as hypohydrated subjects, would have a thermoregulatory advantage from acute polycythemia during exercise in the heat. Five heat-acclimated males attempted four heat stress tests (HSTs): two pre- and two postinfusion. Autologous erythrocyte infusion was accomplished with 500 ml of a NaCl-glucose-phosphate solution containing approximately 60% hematocrit. One HST, both pre- and postinfusion, was done while subjects were euhydrated, and one HST was done while subjects were hypohydrated (-5% of body wt). After 30 min of rest in a 20 degrees C antechamber, the HST consisted of a 120-min exposure (2 repeats of 15 min rest and 45 min walking) in a hot (35 degrees C, 45% relative humidity) environment. The findings concerning acute polycythemia in heat-acclimated subjects are summarized: 1) polycythemia increased (P less than 0.05) sweating rate and reduced (P less than 0.01) core temperature during exercise-heat stress for both euhydrated and hypohydrated subjects; 2) the erythrocyte infusion caused an increased (P less than 0.05) plasma volume and increased (P less than 0.01) blood volume; 3) the increased plasma volume was associated with an increased (P less than 0.05) total circulating protein mass; 4) the increased total circulating protein mass tended to better maintain plasma volume when hypohydrated; and 5) heat acclimation may increase extravascular protein mass. Therefore, it is concluded that erythrocyte infusion provides a thermoregulatory advantage during exercise in the heat for heat acclimated subjects when both euhydrated and hypohydrated.

Thermoregulatory responses of middle-aged and young men during dry-heat acclimation

Thermoregulatory responses during heat acclimation were compared between nine young (mean age 21.2 yr) and nine middle-aged men (mean age 46.4 yr) who were matched (P greater than 0.05) for body weight, surface area, surface area-to-weight ratio, percent body fat, and maximal aerobic power. After evaluation in a comfortable environment (22 degrees C, 50% relative humidity), the men were heat acclimated by treadmill walking (1.56 m/s, 5% grade) for two 50-min exercise bouts separated by 10 min of rest for 10 consecutive days in a hot dry (49 degrees C ambient temperature, 20% relative humidity) environment. During the first day of heat exposure performance time was 27 min longer (P less than 0.05) for the middle-aged men, whereas final rectal and skin temperatures and heart rate were lower, and final total body sweat loss was higher (P less than 0.05) compared with the young men. These thermoregulatory advantages for the middle-aged men persisted for the first few days of exercise-heat acclimation (P less than 0.05). After acclimation no thermoregulatory or performance time differences were observed between groups (P greater than 0.05). Sweating sensitivity, esophageal temperature at sweating onset, and the sweating onset time did not differ (P greater than 0.05) between groups either pre- or postacclimatization. Plasma osmolality and sodium concentration were slightly lower for the young men both pre- and postacclimatization; however, both groups had a similar percent change in plasma volume from rest to exercise during these tests.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of body fat in the prediction of the metabolic response for immersion in cold water

Several empirical models for predicting the metabolic response to a lowered body temperature have been evaluated against available data of young healthy males immersed in cold water under resting conditions. Nude immersions took place in 20 and 24 degrees C water for 1 h, and clothed immersions took place in 10 and 15 degrees C for 3 h. The data were pooled according to low and high percent body fat (%BF). Decreases in the mean weighted skin temperature (Tsk) ranged from 5.3 to 11.9 degrees C and decreases in the core temperature (Tc) ranged from 0.56 to 1.54 degrees C, while increases in the metabolic rate over the immersion period ranged from 34 to 256 W. Through regression analysis, an inverse relationship between %BF and the metabolic response for a given lowered Tsk and lowered Tc was established. When this relationship was explicitly applied to the models, significant improvements in their predictive capability were found. Variables such as body weight, body surface area, and the rate of change of Tsk were not found to contribute to the predictive capability of the models.

Autologous red blood cell reinfusion: effects on stress and fluid regulatory hormones during exercise in the heat

This study assessed the effects of induced erythrocythemia on stress and fluid regulatory hormones during walking exercise in the heat. Six unacclimated male subjects received approximately 600 ml of a sterile saline solution containing 50% volume-to-volume of autologous erythrocytes. Three heat stress tests (HSTs) were attempted: one approximately 2 weeks prior to the reinfusion procedure, a second 48 h after the reinfusion procedure, and a third 1 week later, corresponding to 9 d subsequent to reinfusion. Each HST comprised three consecutive 45-min exercise and 15-min rest intervals (VO2 approximately 2.0 L.min-1, 1.56 m.s-1, 6% incline, 35 degrees C, 45% rh). Blood was withdrawn before the HST and 30 min into each exercise (EX) bout. In all three HST's plasma cortisol (PC) levels were significantly (p less than 0.01) reduced during the first EX bout compared to preexercise levels, and then progressively increased during the second and third EX intervals during HST 1. During HST 2 (48 h postinfusion), however, PC levels were significantly (p less than 0.05) reduced in two blood samples (EX 2, 3) compared to the same blood samples from HST-1 (preinfusion). Plasma renin activity (PRA) and aldosterone (ALD) were significantly (p less than 0.01) increased by the exercise/heat stress, but were unaffected by erythrocythemia either 48 h or 9 d subsequent to reinfusion. PRA and ALD were correlated (r = 0.84, p less than 0.001) under all conditions. We concluded from this study that acutely induced erythrocythemia reduced the stress response to consecutive exercise/heat intervals as manifested in PC responses during HST 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermoregulatory model for immersion of humans in cold water

The mathematical models of thermoregulation of Stolwijk and Hardy, and Montgomery were used to develop a model suitable for the simulation of human physiological responses to cold-water immersion. Data were obtained from experiments where 13 healthy male volunteers were totally immersed under resting and nude conditions for 1 h in water temperatures of 20 and 28 degrees C. At these temperatures, the mean measured rectal temperature (Tre) fell by approximately 0.9 and 0.5 degrees C, respectively, yet mean measured metabolic rate (M) rose by approximately 275 and 90 W for the low body fat group (n = 7) and 195 and 45 W for the moderate body fat group (n = 6). To predict the observed Tre and M values, the present model 1) included thermal inputs for shivering from the skin independent of their inclusion with the central temperature to account for the observed initial rapid rise in M, 2) determined a thermally neutral body temperature profile such that the measured and predicted initial values of Tre and M were matched, 3) confined the initial shivering to the trunk region to avoid an overly large predicted initial rate of rectal cooling, and 4) calculated the steady-state convective heat loss by assuming a zero heat storage in the skin compartment to circumvent the acute sensitivity to the small skin-water temperature difference when using conventional methods. The last three modifications are unique to thermoregulatory modeling.

CT findings in gastrointestinal perforation by ingested fish bones

Preoperative diagnosis of complications due to foreign bodies in the gastrointestinal tract is uncommon by conventional radiographic methods. We present two cases of gastric and duodenal perforation secondary to fish bone ingestion, diagnosed preoperatively by CT.

Elite special forces: physiological description and ergogenic influence of blood reinfusion

We measured the physical exercise capabilities of U.S. Army Special Forces soldiers (male) and determined the subsequent ergogenic influence of autologous blood reinfusion. Twelve subjects (Ss) completed maximal exercise treadmill testing in a comfortable (Ta = 20 degrees C, Tdp = 9 degrees C) environment. Six Ss were later transfused with a 600 ml autologous red blood cell (50% Hct) NaCl glucose-phosphate solution and completed identical maximal exercise tests 3 and 10 d posttransfusion. Pretransfusion, the 12 Ss had a maximal oxygen uptake (VO2max) of 4.36 +/- 0.56 L . min-1 and 55 +/- 4 ml . kg-1 . min-1 with a heart rate of 188 +/- 10 b . min-1 and ventilatory equivalent for oxygen of 37 +/- 3. For the 6 reinfused Ss, hemoglobin and red cell volume (RCV) increased by 10% (p less than 0.05) and 11% (p less than 0.05), respectively, posttransfusion. Reinfusion increased (p less than 0.05) VO2max from 4.28 +/- 0.22 L . min-1 (54 +/- 5 ml . kg-1 . min-1) to 4.75 +/- 0.42 L . min-1 (60 +/- 6 ml . kg-1 . min-1) and 4.63 +/- 0.21 L . min-1 (59 +/- 6 ml . kg-1 . min-1) at 3 and 10 d posttransfusion, respectively. No significant relationship was found between the individual change in RCV and VO2max values pre- to posttransfusion. We conclude that Special Forces soldiers have high levels of aerobic fitness that can be further increased by blood reinfusion for at least 10 d.

Local sweating and cutaneous blood flow during exercise in hypobaric environments

The effect of acute hypobaric hypoxia on local sweating and cutaneous blood flow was studied in four men and four women (follicular phase of menstrual cycle), who exercised at 60% of their altitude-specific peak aerobic power for 35 min at barometric pressures (PB) of 770 Torr (sea level), 552 Torr (2,596 m), and 428 Torr (4,575 m) at an ambient temperature of 30 degrees C. We measured esophageal temperature (Tes), mean skin temperature (Tsk, 8 sites), and local sweating (ms) from dew-point sensors attached to the skin at the chest, arm, and thigh. Skin blood flow (SkBF) of the forearm was measured once each minute by venous occlusion plethysmography. There were no gender differences in the sensitivity (slope) or the threshold of either ms/Tes or SkBF/Tes at any altitude. No change in the Tes for sweating onset occurred with altitude. The mean slopes of the ms/Tes relationships for the three regional sites decreased with increasing altitude, although these differences were not significant between the two lower PBS. The slope of SkBF/Tes was reduced in five of the eight subjects at 428 Torr. Enhanced body cooling as a response to the higher evaporative capacity of the environment is suggested as a component of these peripheral changes occurring in hypobaric hypoxia.