Tunable electrical properties of silicon nanowires via surface-ambient chemistry

p-Type surface conductivity is a uniquely important property of hydrogen-terminated diamond surfaces. In this work, we report similar surface-dominated electrical properties in silicon nanowires (SiNWs). Significantly, we demonstrate tunable and reversible transition of p(+)-p-i-n-n(+) conductance in nominally intrinsic SiNWs via changing surface conditions, in sharp contrast to the only p-type conduction observed on diamond surfaces. On the basis of Si band energies and the electrochemical potentials of the ambient (pH value)-determined adsorbed aqueous layer, we propose an electron-transfer-dominated surface doping model, which can satisfactorily explain both diamond and silicon surface conductivity. The totality of our observations suggests that nanomaterials can be described as a core-shell structure due to their large surface-to-volume ratio. Consequently, controlling the surface or shell in the core-shell model represents a universal way to tune the properties of nanostructures, such as via surface-transfer doping, and is crucial for the development of nanostructure-based devices.

Field electron emission of ZnO nanowire pyramidal bundle arrays

A facile hydrothermal method was adopted to in situ grow ZnO nanowire pyramidal bundle arrays on zinc substrates at low growth temperature without the assistance of catalysts and templates. The bundle arrays were shown to form by sticking of nanowires at their tips. Field electron emission characterization of nanowires bundle arrays revealed a very low turn-on electric field of about 2.3 V/microm and a threshold electric field (corresponding to the field electron emission current density of 10 mA/cm2) of 6.8 V/microm, which are comparable to those observed in carbon nanotube arrays. The bundle arrays also show pronounced long-term field electron emission stability at a high current density. In addition, the formation mechanism of the pyramidal bundled arrays and the origin of the peculiar field electron emission properties were discussed.

Proteins from the Wnt pathway are involved in the pathogenesis and progression of mammary phyllodes tumours

BACKGROUND

The Wnt pathway is important in cell signalling transduction and is involved in the pathogenesis of multiple tumour types. A comprehensive analysis of the expression of Wnt signalling pathway proteins in mammary phyllodes tumours (PTs) has not been previously performed.

AIMS

To evaluate the immunohistochemical expression of Wnt pathway proteins in a cohort of PTs, to determine their role in tumour pathogenesis and to identify any associations with patient outcome.

METHODS

65 PTs (34 benign, 23 borderline and 8 malignant) diagnosed at a single institution between 1990 and 2006 were analysed. Immunohistochemical stains were performed on tissue microarrays for beta-catenin, Wnt1, Wnt5a, SFRP4 and E-cadherin. Stroma and epithelium were scored separately.

RESULTS

Stromal cytoplasmic Wnt5a and SFRP4 expression showed significant progressive increases in expression with increasing grade (p = 0.002 and p = 0.02 respectively). Epithelial membranous and stromal nuclear beta-catenin, epithelial cytoplasmic Wnt1 and epithelial E-cadherin all also showed increasing expression with increasing tumour grade, however, the differences were not significant. Disease-free survival was significantly decreased (p = 0.0017) with positive epithelial E-cadherin staining.

CONCLUSIONS

Results suggest that alterations in the Wnt pathway are important in the progression and in the epithelial and stromal interactions in PTs. They have important implications for understanding the pathogenesis of these uncommon but clinically important tumours.

Oestrogen receptor beta expression in pleomorphic adenomas of the parotid gland

AIMS

Pleomorphic adenomas of the salivary gland have gender and age distributions suggesting that oestrogen has a causal role. However, oestrogen receptor (ER)alpha is expressed at low levels in normal salivary gland tissues and data from salivary gland tumours are conflicting. There is preliminary evidence that the recently described ERbeta may be the major ER in salivary gland tissue. The aim of this study was to determine the nature and extent of ERbeta expression in pleomorphic adenomas of the salivary gland.

METHODS

Pleomorphic adenomas and normal tissues of the parotid gland from 49 patients were tested for ERalpha and ERbeta expression by semiquantitative immunohistochemistry. Associations were sought with patient age and gender.

RESULTS

ERalpha and ERbeta expression was localised mainly to the nuclei of ductal cells in normal tissues and the epithelial components in pleomorphic adenomas. Within each tissue and receptor type there were no associations between ER positivity and patient age or gender. ERbeta was expressed in almost twice as many normal tissues and pleomorphic adenomas as ERalpha. Expression of ERbeta was also significantly higher in tumour compared with normal tissues.

CONCLUSIONS

This is thought to be the first study of ERbeta in pleomorphic adenomas of the salivary gland. Findings support ERbeta as the major ER in salivary glands, and provide evidence that ERbeta may have a role in the development of pleomorphic adenomas of the salivary gland.

Coaxial nanocables of p-type zinc telluride nanowires sheathed with silicon oxide: synthesis, characterization and properties

Coaxial nanocables with a single-crystalline zinc telluride (ZnTe) nanowire core and an amorphous silicon oxide (SiO(x)) shell have been synthesized via a simple one-step chemical vapor deposition (CVD) method on gold-decorated silicon substrates. The single-crystal ZnTe nanowire core is in zinc-blende structure along the [111] direction, while the uniform SiO(x) shell fully covers the core with no observable pin-hole or crack. Formation mechanisms of the ZnTe-SiO(x) nanocables are discussed. The ZnTe nanowire core shows p-type electrical properties while the SiO(x) shell acts as an effective insulating layer. The ZnTe-SiO(x) nanocables may have potential applications in nanoscale devices, such as p-type FETs and nanosensors.

"Real-life" effectiveness of omalizumab in patients with severe persistent allergic asthma: The PERSIST study

OBJECTIVE

To evaluate the 16- and 52-week effectiveness of add-on omalizumab treatment under real-life heterogeneity in patients, settings, and physicians in an open-label, multicenter, pharmaco-epidemiologic study of patients with severe persistent allergic asthma in Belgium.

METHODS

Effectiveness outcomes included improvement in 2005 global initiative for asthma (GINA) classification, physician-rated global evaluation of treatment effectiveness (GETE), quality of life (Juniper asthma-related quality of life (AQLQ) and European quality of life questionnaire 5 dimensions (EQ-5D)), and severe asthma exacerbations. Patients studied included both intent-to-treat and per-protocol populations.

RESULTS

The sample (n=158) had a mean age of 48.17+/-17.18 years, and a slight majority were female (53.8%). Despite being treated with high-dose inhaled corticosteroids and long-acting beta2-agonists, all patients experienced frequent symptoms and had exacerbations in the past year. At 16 weeks, >82% had good/excellent GETE (P values <0.001), >82% had an improvement in total AQLQ scores of > or =0.5 points (P<0.001), and >91% were severe exacerbation-free (P<0.001). At 52 weeks, >72% had a good/excellent GETE rating (P<0.001), >84% had improvements in total AQLQ score of > or =0.5 points (P<0.001), >56% had minimally important improvements in EQ-5D utility scores (P=0.012), and >65% were severe exacerbation-free (P<0.001). Significant reductions in healthcare utilization compared to the one year prior to treatment were noted.

CONCLUSION

The PERSIST study shows better physician-rated effectiveness, greater improvements in quality of life, greater reductions in exacerbation rates, and greater reductions in healthcare utilization than previously reported in efficacy studies. Under real-life conditions, omalizumab is effective as add-on therapy in the treatment of patients with persistent severe allergic asthma.

High-quality Graphenes via a facile quenching method for field-effect transistors

Single- and few-layer graphene sheets with sizes up to 0.1 mm were fabricated by simply quenching hot graphite in an ammonium hydrogen carbonate aqueous solution. The identity and thickness of graphene sheets were characterized with transmission electron microscopy, atomic force microscopy, and Raman spectroscopy. In addition to its simplicity and scalability, the present synthesis can produce graphene sheets with excellent qualities in terms of sizes, purity, and crystal quality. The as-produced graphene sheets can be easily transferred to solid substrates for further processing. Field-effect transistors based on individual graphenes were fabricated and shown to have high ambipolar carrier mobilities.

Vertically aligned p-type single-crystalline GaN nanorod arrays on n-type Si for heterojunction photovoltaic cells

Vertically aligned Mg-doped GaN nanorods have been epitaxially grown on n-type Si substrate to form a heterostructure for fabricating p-n heterojunction photovoltaic cells. The p-type GaN nanorod/n-Si heterojunction cell shows a well-defined rectifying behavior with a rectification ratio larger than 10(4) in dark. The cell has a high short-circuit photocurrent density of 7.6 mAlcm2 and energy conversion efficiency of 2.73% under AM 1.5G illumination at 100 mW/cm2. Moreover, the nanorod array may be used as an antireflection coating for solar cell applications to effectively reduce light loss due to reflection. This study provides an experimental demonstration for integrating one-dimensional nanostructure arrays with the substrate to directly fabricate heterojunction photovoltaic cells.

Factors that affect longevity of intravenous cannulas: a prospective study

BACKGROUND

Few guidelines exist to guide medical personnel on the most successful means of achieving sustained intravenous cannulation. This study examines the impact of gauge and site of intravenous cannulas (IC) on the longevity of ICs in hospitalized patients.

METHODS

A prospective study was conducted on 500 ICs inserted into patients of St Vincent's Private hospital from December 2005 to June 2006. Patients were followed until the IC had been removed or changed. Statistical analysis was performed using Cox proportional hazards.

RESULTS

Of the 500 ICs inserted, 37% were 18 g, 46% were 20 g and 18% were 22 g. Gauge of IC was the most significant predictor of increased longevity of IC (P = 0.0002, RR = 1.17, 95% CI 1.08-1.27). The median survival of 18, 20 and 22 g were 57 h (95% CI 49-72), 43 h (95% CI 36-48.5) and 29 h (95% CI 24-40.5), respectively. The site of IC placement influenced the longevity of ICs (P = 0.005, RR= 0.7, 95% CI 0.55-0.9), as did male gender (P = 0.03, RR = 0.76, 95% CI 0.6-0.97). However in subgroup analysis, the most marked effect on IC longevity was evident in those patients with 18 g placed in the forearm/wrist (median 72 h) with less marked changes in other site/gauge combinations. In contrast, 22 g ICs placed in the hand had a median lifespan of 29 h.

CONCLUSION

IC gauge and site of placement are important factors in determining IC longevity. 18 g ICs placed in the forearm/wrist can considerably increase the longevity of ICs and should be attempted in patients who require sustained cannulation.

p-Type ZnO nanowire arrays

Well-aligned ZnO nanowire (NW) arrays with durable and reproducible p-type conductivity were synthesized on alpha-sapphire substrates by using N2O as a dopant source via vapor-liquid-solid growth. The nitrogen-doped ZnO NWs are single-crystalline and grown predominantly along the [110] direction, in contrast to the [001] direction of undoped ZnO NWs. Electrical transport measurements reveal that the nondoped ZnO NWs exhibit n-type conductivity, whereas the nitrogen-doped ZnO NWs show compensated highly resistive n-type and finally p-type conductivity upon increasing N2O ratio in the reaction atmosphere. The electrical properties of p-type ZnO NWs are stable and reproducible with a hole concentration of (1-2) x 10(18) cm(-3) and a field-effect mobility of 10-17 cm2 V(-2) s(-1). Surface adsorptions have a significant effect on the transport properties of NWs. Temperature-dependent PL spectra of N-doped ZnO NWs show acceptor-bound-exciton emission, which corroborates the p-type conductivity. The realization of p-type ZnO NWs with durable and controlled transport properties is important for fabrication of nanoscale electronic and optoelectronic devices.

Phylogenetic analysis of swine influenza viruses recently isolated in Korea

Several influenza A viral subtypes were isolated from pigs during a severe outbreak of respiratory disease in Korea during 2005 and 2006. They included a classical swine H1N1 subtype, two swine-human-avian triple-recombinant H1N2 subtypes, and a swine-human-avian triple-recombinant H3N2 subtype. In the current study, genetic characterization to determine the probable origin of these recent isolates was carried out for the first time. Phylogenetic analysis indicated that all the recent Korean isolates of H1N1, H1N2, and H3N2 influenza are closely related to viruses from the United States. Serologic and genetic analysis indicated that the Korean H1N2 viral subtypes were introduced directly from the United States, and did not arise from recombination between Korean H1N1 and H3N2. We suggest that the H1N1, H1N2, and H3N2 viral subtypes that were isolated from the Korean swine population originated in North America, and that these viruses are currently circulating in the Korean swine population.

Post-operative health related quality of life assessment in scoliosis patients

Adolescent Idiopathic Scoliosis is a spinal deformity which affects patients' self image and confidence. Surgery is offered when the curve is more than 50 degrees based on its likelihood of progression. Studies on the radiological outcome of scoliosis correction are abundant. Therefore, it is the objective of this study to evaluate the health related quality of life in scoliosis patients who had undergone surgical correction in University Malaya Medical Center, Kuala Lumpur, Malaysia using Scoliosis Research Society-22 (SRS-22) patient questionnaire. This is a prospective evaluation of SRS-22 scores of thirty eight patients operated in our center over the past five years with a minimum follow up of one year. There were thirty two females and six males. Twenty six (68.4%) were Chinese, eight (21.1%) Malay and four (10.5%) Indian patients. The age of the patients ranged from twelve to twenty eight years, with a mean age of 18.4 +/- 3.5. Based on the King and Moe's classification, sixteen patients had King's 3 curve. The mean pre-operative Cobb angle was 68.6 degree and post-operative Cobb angle was 35.8 degree. The average curve correction was 48.5%. The overall score for SRS-22 was 4.2. The SRS-22 scores were highest for the pain domains and lowest for the functional domains. Satisfaction domain scored 4.3. The function domain scored significantly higher in those who have twenty four months or less follow up duration. Curve magnitude and the amount of correction did not significantly alter the SRS scores. In conclusion, patients were satisfied with the outcome of their operation. Although pain was common, the intensity of the pain was minimal. The amount of curve correction did not correlate with the quality of life after operation.

One-step multiplex RT-PCR for detection and subtyping of swine influenza H1, H3, N1, N2 viruses in clinical samples using a dual priming oligonucleotide (DPO) system

The swine influenza virus (SIV) H1N1, H1N2, and H3N2 subtypes circulate in Korean farm. A novel multiplex RT-PCR (m-RT-PCR) was developed to detect and subtype swine influenza viruses. This m-RT-PCR assay could identify H1, H3, N1 and N2 from clinical samples in single tube reaction using DPO system. Korean SIVs are closely related to the United States influenza viruses, and primers were developed for SIV from North American viruses and recently Korean isolates. The sensitivity of the m-RT-PCR was 10TCID(50)/ml for H1N1, H1N2 or H3N2. The lowest viral concentrations detected by single PCR were 1TCID(50)/ml for each subtype. Non-specific reactions were not observed when other viruses and bacteria were used to assess the m-RT-PCR. The results of m-RT-PCR were more effective than virus isolation or hemagglutination (HA) test. This assay using a DPO system provides a rapid, sensitive, and cost-effective laboratory diagnosis for detecting and subtyping of SIV in pigs.

Cyclin D1 and p16 expression in pleomorphic adenoma and carcinoma ex pleomorphic adenoma of the parotid gland

AIMS

To compare cyclin D1 and p16(ink4) (p16) expression in normal tissue, pleomorphic adenoma (PA) and carcinoma ex pleomorphic adenoma (CXPA) of the parotid gland.

METHODS AND RESULTS

Immunohistochemistry was used to examine cyclin D1 and p16 expression in 43 parotid tumours (29 PAs and 14 CXPAs). Cyclin D1 and p16 were both significantly more likely to be expressed in the neoplastic than in the normal epithelial and stromal components of PA and CXPA (P < 0.001 and P < 0.005, respectively). Cyclin D1 was more likely to be expressed in the malignant components of CXPA than in the benign components of PA (50% versus 31% and 31%, respectively), but the trend was not statistically significant. There was no evidence of this association for p16 (corresponding positivity rates 69% versus 81% and 52%).

CONCLUSIONS

Our findings provide preliminary evidence of roles for cyclin D1 and p16 in the development of PA and for cyclin D1 in the progression of PA to CXPA.

Why alpha-antiplasmin must be converted to a derivative form for optimal function

BACKGROUND

Human alpha(2)-antiplasmin (alpha(2)AP), the primary inhibitor of fibrinolysis, is secreted from the liver into plasma as a 464-residue protein with Met as the N-terminus. An R6W polymorphism has been suggested to affect fibrinolytic rate. Within circulating blood, antiplasmin-cleaving enzyme (APCE) cleaves Met-alpha(2)AP(R6) faster than Met-alpha(2)AP(W6) at the Pro12-Asn13 bond to yield Asn-alpha(2)AP.

OBJECTIVES

To compare Met-alpha(2)AP(R6), Met-alpha(2)AP(W6) and Asn-alpha(2)AP for crosslinking with fibrin and the ability to protect fibrin from digestion by plasmin.

METHODS AND RESULTS

Asn-alpha(2)AP utilizes Gln2 (Gln14 in Met-alpha(2)AP) to become crosslinked to fibrin approximately twelvefold faster than Met-alpha(2)AP(R6) or Met-alpha(2)AP(W6), and this enhances the resistance of fibrin to plasmin. All three forms of alpha(2)AP inhibit plasmin at identical rates. The N-terminal 12-residue peptide of Met-alpha(2)AP slows crosslinking of Met-alpha(2)AP(R6) or Met-alpha(2)AP(W6) by limiting access of factor XIIIa to Gln14 rather than shifting crosslinking to other Gln residues. Edman sequencing and mass analyses of tryptic peptides from each alpha(2)AP crosslinked with 5-(biotinamido)pentylamine showed Gln14 as the only major crosslinking site. Residues 5-8, GRQL in Met-alpha(2)AP(R6), and residues 1-8, MEPLGWQL in Met-alpha(2)AP(W6), slow fibrin crosslinking.

CONCLUSION

Gln14 in both Met-alpha(2)AP(R6) and Met-alpha(2)AP(W6) is sheltered by the N-terminal 12-residue peptide, which, when cleaved, yields Asn-alpha(2)AP, which is rapidly crosslinked to fibrin and maximally protects it from plasmin. The R6 W polymorphism in Met-alpha(2)AP does not affect its crosslinking to fibrin, but it does slow cleavage by APCE and reduces the amount of Asn-alpha(2)AP available for rapid crosslinking to fibrin.

Hydroxychavicol, a novel betel leaf component, inhibits platelet aggregation by suppression of cyclooxygenase, thromboxane production and calcium mobilization

BACKGROUND AND PURPOSE

Platelet hyperactivity is important in the pathogenesis of cardiovascular diseases. Betel leaf (PBL) is consumed by 200-600 million betel quid chewers in the world. Hydroxychavicol (HC), a betel leaf component, was tested for its antiplatelet effect.

EXPERIMENTAL APPROACH

We tested the effect of HC on platelet aggregation, thromboxane B(2) (TXB(2)) and reactive oxygen species (ROS) production, cyclooxygenase (COX) activity, ex vivo platelet aggregation and mouse bleeding time and platelet plug formation in vivo. The pharmacokinetics of HC in rats was also assessed.

KEY RESULTS

HC inhibited arachidonic acid (AA) and collagen-induced platelet aggregation and TXB(2) production. HC inhibited the thrombin-induced TXB(2) production, but not platelet aggregation. SQ29548, suppressed collagen- and thrombin-induced TXB(2) production, but not thrombin-induced platelet aggregation. HC also suppressed COX-1/COX-2 enzyme activity and the AA-induced ROS production and Ca(2+) mobilization. HC further inhibited the ex vivo platelet aggregation of platelet-rich plasma (>100 nmole/mouse) and prolonged platelet plug formation (>300 nmole/mouse) in mesenteric microvessels, but showed little effect on bleeding time in mouse tail. Moreover, pharmacokinetics analysis found that more than 99% of HC was metabolized within 3 min of administration in Sprague-Dawley rats in vivo.

CONCLUSIONS AND IMPLICATIONS

HC is a potent COX-1/COX-2 inhibitor, ROS scavenger and inhibits platelet calcium signaling, TXB(2) production and aggregation. HC could be a potential therapeutic agent for prevention and treatment of atherosclerosis and other cardiovascular diseases through its anti-inflammatory and antiplatelet effects, without effects on haemostatic functions.

Cyclin A expression and its diagnostic value in pleomorphic adenoma and carcinoma expleomorphic adenoma of the parotid gland

AIMS

To investigate cyclin A expression in pleomorphic adenoma (PA) and carcinoma expleomorphic adenoma (CXPA) of the parotid gland with a view to assessing its potential value as a diagnostic marker for CXPA.

METHODS AND RESULTS

Cyclin A expression in PA and CXPA was studied using semiquantitative immunohistochemistry. The epithelial component of the tumours expressed cyclin A in a statistically significantly (P < 0.005) higher number of CXPA cases (86%) compared with the PA cases (39%). Cyclin A was not expressed in normal salivary tissues of PA and CXPA.

CONCLUSIONS

High cyclin A expression is a useful marker for the pathological diagnosis of CXPA.

Isolation and phylogenetic analysis of H1N1 swine influenza virus isolated in Korea

A swine influenza H1N1 virus was isolated from a pig during a severe outbreak of respiratory disease in Korea. All genes of the H1N1 isolate, including hemagglutinin (HA), neuraminidase (NA), matrix (M), nucleoprotein (NP), non-structural (NS), PA, PB1 and PB2, were of swine origin. Also, all these genes showed a close phylogenic relationship with those of H1N1 viruses previously isolated from pigs in the United States. These results suggest that North American swine influenza virus has actually been transmitted to pigs in Korea.

Study on OELs for enzyme-containing detergent in China

This study is aimed at setting occupational exposure levels for total detergent dust and enzymes in detergent industries. The study population consisted of 795 workers from four enzyme-containing detergent manufacturing plants (A1, A2, B1 and B2), and 156 control workers from an electronic assembly factory. Work environment monitoring was conducted using high volume of air sampler fro measuring the concentration of total dust (mg/m3), and analyzing the level of enzyme (ng/m3) by ELISA method. A standard questionnaires, pulmonary function test, and skin prick test are used to assess health effects. The levels of detergent total dust varied from 0.2 mg/m3 to 12.54 mg/m3. For enzyme levels, in A1, B1 and B2, the concentration ranged from non-detectable to 9.92 ng/m3 and in A2, the concentration was analyzed by enzyme activity methods and was expressed as Gu/m3 (1 Gu/m3 = 16 ng/m3). The concentration is between 0.16-31.36 ng/m3. Non-specific irritation rates in exposed workers were significantly higher than that in controls. Based on the data collected from A1, B1 and control plants, 95% benchmark dose lower bound were calculated as 1.17 mg/m3. The difference of pulmonary function between exposed workers and controls is not significant. The results of SPT showed that neither Savinase- nor Alcalase-induced sensitization was found in controls. The prevalence rates of sensitization for Savinase and Alcalase were ranged between 3.2% and 31% in all enzyme-containing detergent manufacturers investigated. No case of occupational asthma was observed. For total dust, 1 mg/m3 is suggested as permissible concentration-time weighted average (PC-TWA), and 2 mg/m3 as permissible concentration-short term exposure limit (PC-STEL). For the enzyme Subtilisins, 15 ng/m3 is suggested as PC-TWA, and 30 ng/m3 as PC-STEL.

Modulation of 1-methyl-4-phenylpyridinium-induced mitochondrial dysfunction and cell death in PC12 cells by K(ATP) channel block

The present study investigated the effect of 5-hydroxydecanoate, a selective mitochondrial K(ATP) channel blocker, on the cytotoxicity of neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) in differentiated PC12 cells. 5-Hydroxydecanoate and glibenclamide (a cell surface and mitochondrial K(ATP) channel inhibitor) reduced the MPP(+)-induced cell death and GSH depletion and showed a maximal inhibitory effect at 5 and 10 microM, respectively. Addition of 5-hydroxydecanoate attenuated the MPP(+)-induced nuclear damage, changes in the mitochondrial membrane permeability and increase in the reactive oxygen species formation in PC12 cells. The results show that 5-hydroxydecanote may prevent the MPP(+)-induced viability loss in PC12 cells by suppressing formation of the mitochondrial permeability transition, leading to the cytochrome c release and caspase-3 activation. This effect appears to be accomplished by the inhibitory action on the formation of reactive oxygen species and the depletion of GSH. The blockade of mitochondrial K(ATP) channels seems to prevent the MPP(+)-induced neuronal cell damage.

Degeneration and apoptosis of endometrial cells in the bitch

The relationships between changes in plasma progesterone concentrations, degeneration of the luminal epithelium, the occurrence of apoptosis of endometrial cells and endometrial leucocyte populations in the bitch were determined. Mature bitches (n = 15) were euthanized and necropsied when in diestrus (Days 7-75, n = 12) or in anestrus (Days 10, 32 and 53). Degeneration of the luminal epithelium was observed in bitches in late diestrus (Days 38-75, n = 5) when plasma progesterone concentrations were decreasing and in anestrus (Days 10 and 32, n = 2) when plasma progesterone concentrations were < 0.5 ng/mL. Endometrial leucocyte populations increased after degeneration of the luminal epithelium (around Day 42 of diestrus). Apoptosis was mainly observed in the basal glandular epithelial cells and endothelial cells of blood capillaries in all except anestrous bitches. Very few apoptotic cells were found in the superficial glandular epithelial cells and stromal cells. Higher apoptotic indices were detected in the basal glandular epithelium on Days 12-42 of diestrus than at other stages. Therefore, apoptosis of glandular basal epithelial cells occurred mainly in early diestrus, degeneration of cells of the luminal epithelium occurred from mid-diestrus to early anestrus, and the increase in leucocyte numbers may have been a consequence and not a cause of luminal epithelial degeneration.