Hormone therapy in elderly women; a comparative study with alendronate of the effects on bone, cardiovascular risk factors, periodontal conditions and quality of life

Thirty percent of 70-year-old women have osteoporosis; after age of 80 its prevalence is up to 70%. Postmenopausal women with osteoporosis seem to be at an increased risk for cardiovascular events, and deterioration of oral health, as shown by attachment loss of teeth, which is proportional to the severity of osteoporosis. Osteoporosis can be treated with many different medication, e.g. estrogen and alendronate. We randomized 90 elderly osteoporotic women (65-80 years of age) to receive hormone therapy (HT)(2mg E2+NETA), 10mg alendronate, and their combination for two years and compared their effects on bone mineral density (BMD) and turnover, two surrogate markers of the risk of cardiovascular diseases, C-reactive protein (CRP) and E-selectin, as well as oral health. The effect of HT on health-related quality of life (HRQoL) was studied in the population-based cohort of 1663 postmenopausal women (mean age 68 yr) (585 estrogen users and 1078 non-users). BMD was measured with dual-energy X-ray absorptiometry (DXA) at 0, 12 and 24 months. Urinary N-telopeptide (NTX) of type I collagen, a marker of bone resorption, and serum aminoterminal propeptide of human type I procollagen (PINP), a marker of bone formation, were measured every six months of treatment. Serum CRP and E-selectin, were measured at 0, 6, and 12 months. Dental, and periodontal conditions, and gingival crevicular fluid (GCF) matrix metalloproteinase (MMP)-8 levels were studied to evaluate the oral health status and for the mouth symptoms a structured questionnaire was used. The HRQoL was measured with 15D questionnaire. Lumbar spine BMD increased similarly in all treatment groups (6.8-8.4% and 9.1-11.2%). Only HT increased femoral neck BMD at both 12 (4.9%) and 24 months (5.8%), at the latter time point the HT group differed significantly from the other groups. HT reduced bone marker levels of NTX and PINP significantly less than other two groups.Oral HT significantly increased serum CRP level by 76.5% at 6 and by 47.1% (NS) at 12 months, and decreased serum E-selectin level by 24.3% and 30.0%. Alendronate had no effect on these surrogate markers. Alendronate caused a decrease in the resting salivary flow rate and tended to increase GCF MMP-8 levels. Otherwise, there was no effect on the parameters of oral health. HT improved the HRQoL of elderly women significantly on the dimensions of usual activities, vitality and sexual activity, but the overall improvement in HRQoL was neither statistically significant nor clinically important. In conclusion, bisphosphonates might be the first option to start the treatment of postmenopausal osteoporosis in the old age.

Evaluation of the Biocompatibility of Poly (ortho ester), Copolymer of ε-caprolactone/D,L-lactide and the Composite of Copolymer of ε-caprolactone/D,L-lactide and Tricalciumphosphate as Bone Filling Material

The purpose of this series of studies was to evaluate the biocompatibility of poly (ortho) ester (POE), copolymer of ε-caprolactone and D,L-lactide [P (ε-CL/DL-LA)] and the composite of P(ε-CL/DL-LA) and tricalciumphosphate (TCP) as bone filling material in bone defects. Tissue reactions and resorption times of two solid POE-implants (POE 140 and POE 46) with different methods of sterilization (gamma- and ethylene oxide sterilization), P(ε-CL/DL-LA)(40/60 w/w) in paste form and 50/50 w/w composite of 40/60 w/w P(ε-CL/DL-LA) and TCP and 27/73 w/w composite of 60/40 w/w P(ε-CL/DL-LA) and TCP were examined in experimental animals. The follow-up times were from one week to 52 weeks. The bone samples were evaluated histologically and the soft tissue samples histologically, immunohistochemically and electronmicroscopically. The results showed that the resorption time of gamma sterilized POE 140 was eight weeks and ethylene oxide sterilized POE 140 13 weeks in bone. The resorption time of POE 46 was more than 24 weeks. The gamma sterilized rods started to erode from the surface faster than ethylene oxide sterilized rods for both POEs. Inflammation in bone was from slight to moderate with POE 140 and moderate with POE 46. No highly fluorescent layer of tenascin or fibronectin was found in the soft tissue. Bone healing at the sites of implantation was slower than at control sites with the copolymer in small bone defects. The resorption time for the copolymer was over one year. Inflammation in bone was mostly moderate. Bone healing at the sites of implantation was also slower than at the control sites with the composite in small and large mandibular bone defects. Bone formation had ceased at both sites by the end of follow-up in large mandibular bone defects. The ultrastructure of the connective tissue was normal during the period of observation. It can be concluded that the method of sterilization influenced the resorption time of both POEs. Gamma sterilized POE 140 could have been suitable material for filling small bone defects, whereas the degradation times of solid EO-sterilized POE 140 and POE 46 were too slow to be considered as bone filling material. Solid material is difficult to contour, which can be considered as a disadvantage. The composites were excellent to handle, but the degradation time of the polymer and the composites were too slow. Therefore, the copolymer and the composite can not be recommended as bone filling material.

Fatigue fractures in military conscripts : A study on risk factors, diagnostics and long-term consequences

Fatigue fracture is an overuse injury commonly encountered in military and sports medicine, and known to relate to intensive or recently intensified physical activity. Bone responds to increased stress by enhanced remodeling. If physical stress exceeds bone s capability to remodel, accumulation of microfractures can lead to bone fatigue and stress fracture. Clinical diagnosis of stress fractures is complex and based on patient s anamnesis and radiological imaging. Bone stress fractures are mostly low-risk injuries, healing well after non-operative management, yet, occurring in high-risk areas, stress fractures can progress to displacement, often necessitating surgical treatment and resulting in prolonged morbidity. In the current study, the role of vitamin D as a predisposing factor for fatigue fractures was assessed using serum 25OHD level as the index. The average serum 25OHD concentration was significantly lower in conscripts with fatigue fracture than in controls. Evaluating TRACP-5b bone resorption marker as indicator of fatigue fractures, patients with elevated serum TRACP-5b levels had eight times higher probability of sustaining a stress fracture than controls. Among the 154 patients with exercise induced anterior lower leg pain and no previous findings on plain radiography, MRI revealed a total of 143 bone stress injuries in 86 patients. In 99% of the cases, injuries were in the tibia, 57% in the distal third of the tibial shaft. In patients with injury, forty-nine (57%) patients exhibited bilateral stress injuries. In a 20-year follow-up, the incidence of femoral neck fatigue fractures prior to the Finnish Defence Forces new regimen in 1986 addressing prevention of these fractures was 20.8/100,000, but rose to 53.2/100,000 afterwards, a significant 2.6-fold increase. In nineteen subjects with displaced femoral neck fatigue fractures, ten early local complications (in first postoperative year) were evident, and after the first postoperative year, osteonecrosis of the femoral head in six and osteoarthritis of the hip in thirteen patients were found. It seems likely that low vitamin D levels are related to fatigue fractures, and that an increasing trend exists between TRACP-5b bone resorption marker elevation and fatigue fracture incidence. Though seldom detected by plain radiography, fatigue fractures often underlie unclear lower leg stress-related pain occurring in the distal parts of the tibia. Femoral neck fatigue fractures, when displaced, lead to long-term morbidity in a high percentage of patients, whereas, when non-displaced, they do not predispose patients to subsequent adverse complications. Importantly, an educational intervention can diminish the incidence of fracture displacement by enhancing awareness and providing instructions for earlier diagnosis of fatigue fractures.

Injection laryngoplasty with autologous fascia for treatment of unilateral vocal fold paralysis

The purpose of this dissertation was to study the applicability of minced autologous fascia graft for injection laryngoplasty of unilateral vocal fold paralysis (UVFP). Permanence of augmentation and host versus graft tissue reactions were of special interest. The topic deals with phonosurgery, which is a subdivision of the Ear, Nose and Throat-speciality of medicine. UVFP results from an injury to the recurrent or the vagal nerve. The main symptom is a hoarse and weak voice. Surgery is warranted for patients in whom spontaneous reinnervation and a course of voice therapy fails to improve the voice. Injection laryngoplasty is a widespread surgical technique which aims to restore glottic closure by augmenting the atrophied vocal muscle, and also by turning the paralyzed vocal fold towards midline. Currently, there exists a great diversity of synthetic, xenologous, homologous, and autologous substances available for injection. An autologous graft is perfect in terms of biocompatibility. Free fascia grafts have been successfully used in the head and neck surgery for decades, but fascia had not been previously applied into the vocal fold. The fascia is harvested from the lateral thigh under local anesthesia and minced into paste by scissors. Injection of the vocal fold is performed in laryngomicroscopy under general anesthesia. Three series of clinical trials of injection laryngoplasty with autologous fascia (ILAF) for patients with UVFP were conducted at the Department of Otorhinolaryngology of the Helsinki University Central Hospital. The follow-up ranged from a few months to ten years. The aim was to document the vocal results and possible morbidity related to graft harvesting and vocal fold injection. To address the tissue reactions and the degree of reabsoprtion of the graft, an animal study with a follow-up ranging from 3 days to 12 months was performed at the National Laboratory Animal Center, University of Kuopio. Harvesting of the graft and injection was met with minor morbidity. Histological analysis of the vocal fold tissue showed that fascia was well tolerated. Although some resorption or compaction of the graft during the first months is evident, graft volume is maintained well. When injected deep and laterally into the vocalis muscle, the fascia graft allows normal vibration of the vocal fold mucosa to occur during phonation. Improvement of voice quality was seen in all series by multiple objective parameters of voice evaluation. However, the vocal results were poor in cases where the nerve trauma was severe, such as UVFP after chest surgery. ILAF is most suitable for correction of mild to moderate glottic gaps related to less severe nerve damage. Our results indicate that autologous fascia is a feasible and safe new injection material with good and stable vocal results. It offers a practical solution for surgeons who treat this complex issue.

Pannus invasion into cartilage and bone in rheumatoid arthritis

Rheumatoid arthritis is the most common of all types of arthritis and despite of intensive research etiology of the disease remains unclear. Distinctive features of rheumatic arthritis comprise continuous inflammation of synovium, in which synovial membrane expands on cartilage leading to pannus tissue formation. Pannus formation, appearance of proteolytic enzymes and osteoclast formation cause articular cartilage and bone destruction, which lead to erosions and permanent joint damage. Proteolytic pathways play major roles in the development of tissue lesions in rheumatoid arthritis. Degradation of extracellular matrix proteins is essential to pannus formation and invasion. Matrix metalloproteinases (MMP) form a large proteolytic enzyme family and in rheumatoid arthritis they contribute to pannus invasion by degrading extracellular matrix and to joint destruction by directly degrading the cartilage. MMP-1 and MMP-3 are shown to be increased during cell invasion and also involved in cartilage destruction. Increase of many cytokines has been observed in rheumatoid arthritis, especially TNF-α and IL-1β are studied in synovial tissue and are involved in rheumatoid inflammation and degradation of cartilage. Underlying bone resorption requires first demineralization of bone matrix with acid secreted by osteoclasts, which exposes the collagen-rich matrix for degradation. Cathepsin K is the best known enzyme involved in bone matrix degradation, however deficiency of this protein in pycnodysostosis patient did not prevent bone erosion and on the contrary pannus tissue invading to bone did not expressed much cathepsin K. These indicate that other proteinases are involved in bone degradation, perhaps also via their capability to replace the role of other enzymes especially in diseases like pycnodysostosis or during medication e.g. using cathepsin K inhibitors. Multinuclear osteoclasts are formed also in pannus tissue, which enable the invasion into underlying bone matrix. Pannus tissue express a receptor activator of nuclear factor kappa B ligand (RANKL), an essential factor for osteoclast differentiation and a disintegrin and a metalloproteinase 8 (ADAM8), an osteoclast-activating factors, involved in formation of osteoclast-like giant cells by promoting fusion of mononuclear precursor cells. The understanding of pannus invasion and degradation of extracellular matrix in rheumatic arthritis will open us new more specific methods to prevent this destructive joint disease.

Pharmacological inhibition of gut-derived serotonin synthesis is a potential bone anabolic treatment for osteoporosis

Osteoporosis is a disease of low bone mass most often caused by an increase in bone resorption that is not sufficiently compensated for by a corresponding increase in bone formation(1). As gut-derived serotonin (GDS) inhibits bone formation(2), we asked whether hampering its biosynthesis could treat osteoporosis through an anabolic mechanism (that is, by increasing bone formation). We synthesized and used LP533401, a small molecule inhibitor of tryptophan hydroxylase-1 (Tph-1), the initial enzyme in GDS biosynthesis. Oral administration of this small molecule once daily for up to six weeks acts prophylactically or therapeutically, in a dose-dependent manner, to treat osteoporosis in ovariectomized rodents because of an isolated increase in bone formation. These results provide a proof of principle that inhibiting GDS biosynthesis could become a new anabolic treatment for osteoporosis.

Modulation of growth by aromatase inhibitor treatment in boys: Efficacy and safety

Without estrogen action, the fusion of the growth plates is postponed and statural growth continues for an exceptionally long time. Aromatase inhibitors, blockers of estrogen biosynthesis, have therefore emerged as a new potential option for the treatment of children with short stature. We investigated the efficacy of the aromatase inhibitor letrozole in the treatment of boys with idiopathic short stature (ISS) using a randomised, placebo-controlled, double-blind research setting. A total of 30 boys completed the two-year treatment. By decreasing estrogen-mediated central negative feedback, letrozole increased gonadotrophin and testosterone secretion in pubertal boys, whereas the pubertal increase in IGF-I was inhibited. Treatment with letrozole effectively delayed bone maturation and increased predicted adult height by 5.9 cm (P0.001), while placebo had no effect on either parameter. The effect of letrozole treatment on near-final height was studied in another population, in boys with constitutional delay of puberty, who received letrozole (n=9) or placebo (n=8) for one year, in combination with low-dose testosterone for six months during adolescence. The mean near-final height of boys randomised to receive testosterone and letrozole was significantly greater than that of boys who received testosterone and placebo (175.8 vs. 169.1 cm, P=0.04). As regards safety, treatment effects on bone health, lipid metabolism, insulin sensitivity, and body composition were monitored in boys with ISS. During treatment, no differences in bone mass accrual were evident between the treatment groups, as evaluated by dual-energy x-ray absorptiometry measurements of the lumbar spine and femoral neck. Bone turnover and cortical bone growth, however, were affected by letrozole treatment. As indicated by differences in markers of bone resorption (U-INTP) and formation (S-PINP and S-ALP), the long-term rate of bone turnover was lower in letrozole-treated boys, despite their more rapid advancement in puberty. Letrozole stimulated cortical bone growth in those who progressed in puberty: the metacarpal index (MCI), a measure of cortical bone thickness, increased more in letrozole-treated pubertal boys than in placebo-treated pubertal boys (25% vs. 9%, P=0.007). The change in MCI correlated positively with the mean testosterone-to-estradiol ratio. In post-treatment radiographic evaluation of the spine, a high rate of vertebral deformities - mild anterior wedging and mild compression deformities - were found in both placebo and letrozole groups. In pubertal boys with ISS treated with letrozole, stimulated testosterone secretion was associated with a decrease in the percentage of fat mass and in HDL-cholesterol, while LDL-cholesterol and triglycerides remained unchanged. Insulin sensitivity, as evaluated by HOMA-IR, was not significantly affected by the treatment. In summary, treatment with the aromatase inhibitor letrozole effectively delayed bone maturation and increased predicted adult height in boys with ISS. Long-term follow-up data of boys with constitutional delay of puberty, treated with letrozole for one year during adolescence, suggest that the achieved gain in predicted adult height also results in increased adult height. However, until the safety of aromatase inhibitor treatment in children and adolescents is confirmed, such treatment should be considered experimental.

Effect of ICSH on Early Pregnancy in Hypophysectomized Pregnant Rats

Moudgal and co-workers1-3 recently reported that the administration to intact pregnant rats of rabbit antiserum ovine interstitial cell stimulating hormone (ICSH) on any one day between the eighth and twelfth days of pregnancy resulted in resorption of foetuses and termination of pregnancy. This effect was readily reversed by the simultaneous administration of progesterone but not by oestradiol-17β. These observations suggested that ICSH was involved in progesterone synthesis and as such is a luteotropic factor in the rat.

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN.

Korkean lämpötilan vaikutus hiiren poskihampaan kiilteen kehitykseen in vitro

Tutkimuksen tarkoituksena oli selvittää kuumetta vastaavan elinviljelylämpötilan vaikutusta hiiren poskihampaiden kiilteen kehittymiseen. Tutkimus tehtiin in vitro ja siinä käytettiin E18- hiiriä, joiden hampaita kasvatettiin ´kuumeessa´ (39 °C) kolmannesta kasvatuspäivästä lähtien, osaa viisi ja osaa kolme päivää. Kontrollihampaita kasvatettiin 37 °C:ssa. Hampaita kasvatettiin yhteensä 11 päivää ja lopuksi ne kuvattiin. Stereomikroskooppikuvista mitattiin kiilteen korkeus ja kruunun korkeus ja laskettiin näiden suhde. Hampaat demineralisoitiin, valettiin parafiiniin, leikattiin leikkeiksi ja värjättiin HE-värjäyksellä. Leikkeistä mitattiin kiilteen paksuus ja kiilteen ja dentiinin yhteispaksuus ja laskettiin näiden suhde. Arvoja verrattiin kasvatusryhmien kesken. Tulokset analysoitiin Mann-Whitney-testillä. Kiilteen paksuus suhteessa kiilteen ja dentiinin yhteispaksuuteen oli pienempi ´kuumehampaissa´. Viisi tai kolme päivää ´kuumeessa´kasvatettujen hampaiden välillä ei ollut juurikaan eroja. Kiilteen korkeus suhteessa kruunun korkeuteen oli pienempi ´kuumehampaissa´ kuin kontrollihampaissa. Korkea lämpötila ei muutoin näyttänyt vaikuttavan hampaiden kehitykseen. Tutkimuksen perusteella voidaan sanoa, että kasvatuslämpötilan nosto kuumeen tasolle aiheuttaa hiiren molaarihampaan kiilteen kehityksen häiriintymistä. Tulos tukee kliinisiä havaintoja, joiden mukaan korkea kuume lapsella voi aiheuttaa kiilteen kehityshäiriöitä.

Early pregnancy termination in rats immunized with denatured chicken riboflavin carrier protein

Immunoneutralization of the maternal riboflavin carrier protein in the pregnant rat with antibodies to chicken egg vitamin carrier has earlier been shown to terminate their pregnancies. In order to understand the nature of the epitopic conformations capable of eliciting antibodies bioneutralizing the endogenous riboflavin carrier protein in the pregnant rat, we compared pregnancy progression in the fertile rodents following active immunization with either the native, SDS-denatured, reduced-carboxymethylated or SDS-treated reduced carboxymethylated avian egg white riboflavin carrier protein. The data revealed that despite the total antibody titers being higher in the animals immunized with the native protein, the antibodies elicited against the denatured avian vitamin carrier exhibited relatively better potencies to bioneutralize the endogenous maternal protein as evidenced by higher rates of early fetal resorption.

Oral health, smoking and adolescence

The present cross-sectional study examined the effect of smoking on oral health in a birth cohort of 15 to 16-year-old Finnish adolescents. The hypothesis was that oral health parameters were poorer among smoking than non-smoking subjects and that a tobacco intervention program could be effective among the adolescents. The study was conducted in the Kotka Health Center, Kotka, Finland. Altogether 501 out of 545 subjects (15- to 16-year-old boys [n = 258] and girls [n = 243]) were clinically examined in 2004 and 2005. The sample frame was a birth cohort of all subjects in 1989 and 1990, living in Kotka. A structured questionnaire was also filled in by the participants to record their general health and health habits, such as smoking, tooth brushing, and medication used. The participants were classified into nonsmokers, current smokers, and former smokers. Subgingival pooled plaque samples were taken and stimulated salivary samples were also collected. The subjects were asked from which of seven professional groups (doctors, school nurses, dental nurses, general nurses, dentists, teachers and media professionals) they would prefer to receive information about tobacco. The two most popular groups they picked up were dentists and school nurses. Current smokers (n=127) were then randomly assigned into three groups: the dentist group (n =44), the school-nurse group (n =42), and the control group (n =39). The intervention was based on a national recommendation of evidence based guidelines by The Finnish Medical Society Duodecim ( 5A counseling system). Two months after the intervention, a second questionnaire was sent to the smokers in the intervention groups. Smoking cessation, smoking quantity per week, and self-rated addiction for smoking (SRA) were recorded. The results were analyzed using the R-statistical program. The results showed that 15% of the subjects had periodontitis. Smokers (25%) had more periodontitis than non-smokers (66%) (p < 0.001). Smoking boys (24%) also had more caries lesions than non-smokers (69%) (p < 0.001), and they brushed their teeth less frequently than non-smokers. Smoking significantly impaired periodontal health of the subjects, even when the confounding effects of plaque and tooth brushing were adjusted. Smoking pack-years, intensified the effects of smoking. Periodontal bacteria Prevotella nigrescens, Prevotella intermedia, Tannerella forsythia and Treponema denticola were more frequently detected among the smokers than non-smokers, especially among smoking girls. Smoking significantly decreased the values of both the salivary periodontal biomarkers MMP-8 (p=0.04) and PMN elastase (p=0.02) in boys. The effect was strengthened by pack years of smoking (MMP-8 p=0.04; elastase p0.01). Of those who participated in the intervention, 19 % quit smoking. The key factors associated with smoking cessation were best friend`s influence, nicotine dependence and diurnal type. When the best friend was not a smoker, the risk ratio (RR) of quit smoking after the intervention was 7.0 (Cl 95% 4.6 10.7). Of the diurnal types, the morning people seemed to be more likely to quit (RR 2.2 [Cl 95% 1.4 3.6]). Nicotine dependence also elicited an opposite effect: those who scored between 3 and 5 dependence scores were less likely to quit. In conclusion, smoking appears to be a major etiological risk factor for oral health. However, the early signs of periodontal disease were mild in the subjects studied. Based on the opinions of the adolescent s, dental professionals may have a key position in their smoking cessation. The harmful effects of smoking on oral health could be used in counselling. Best friend`s influence, nicotine dependence and diurnal type, all factors associated with smoking cessation, should be taken more carefully into account in the prevention programs for adolescents.

Establishment of the functional importance of thiamin carrier protein in pregnant rats by using monoclonal antibodies

Monoclonal antibodies (mAbs) to chicken thiamin carrier protein (TCP) have been produced by hybridoma technology to identify the crucial epitopes involved in bioneutralization of the vitamin carrier. The monoclonality of these mAbs (A4C4, F3H6, H8H3, C8C1 and G7H10) was sought to be confirmed by sub-class isotyping; they all belong to IgG1, k type. The epitopes recognized by all the five mAbs are conserved in TCP from the chicken to the rat as assessed by liquid phase RIA and immunoprecipitation of I-125-labelled proteins from pregnant rat serum. Among these mAbs, passive immunization of pregnant rats with the mAb C8C1 only on three consecutive days (day 10, 11 and 12) resulted in embryonic resorption. These results demonstrate the importance of epitopic structure specified by the mAb C8C1 on TCP during pregnancy in rats.

Low electric field, easily reversible electrical set and reset processes in a Ge15Te83Si2 glass for phase change memory applications

We report here an easily reversible set-reset process in a new Ge15Te83Si2 glass that could be a promising candidate for phase change random access memory applications. The I-V characteristics of the studied sample show a comparatively low threshold electric field (E-th) of 7.3 kV/cm. Distinct differences in the type of switching behavior are achieved by means of controlling the on state current. It enables the observation of a threshold type for less than 0.7 mA beyond memory type (set) switching. The set and reset processes have been achieved with a similar magnitude of 1 mA, and with a triangular current pulse for the set process and a short duration rectangular pulse of 10 msec width for the reset operation. Further, a self-resetting effect is seen in this material upon excitation with a saw-tooth/square pulse, and their response of leading and trailing edges are discussed. About 6.5 x 10(4) set-reset cycles have been undertaken without any damage to the device. (C) 2011 American Institute of Physics. doi: 10.1063/1.3574659]

Evaporation Heat Transfer Coefficient in a Capillary Pumped Loop and Loop Heat Pipe for Different Working Fluids

Capillary pumped loop (CPL) and loop heat pipe (LHP) are passive two-phase heat transport devices. They have been gaining importance as a part of the thermal control system of spacecraft. The evaporation heat transfer coefficient at the tooth-wick interface of an LHP or CPL has a significant impact on the evaporator temperature. It is also the main parameter in sizing of a CPL or LHP. Experimentally determined evaporation heat transfer coefficients from a three-port CPL with tubular axially grooved (TAG) evaporator and a TAG LHP with acetone, R-134A, and ammonia as working fluids are presented in this paper. The influences of working fluid, hydrodynamic blocks in the core, evaporator configuration (LHP or CPL), and adverse elevation (evaporator above condenser) on the heat transfer coefficient are presented.