Admission screening form and osteoporosis educational appointment: a novel fracture liaison service system for identifying osteoporosis patients and facilitating medication initiation.

Our FLS team aimed to ensure that patients admitted to the orthopedic department were promptly initiated for medication and identify and initiate medication for patients admitted to other departments. Our innovative FLS system along with admission screening and osteoporosis education have proven effective in identifying patients with osteoporosis and initiating medication. PURPOSE: The fracture liaison service (FLS) plays a crucial role in the secondary prevention of fragility fractures by involving various medical professionals. Our FLS team had two goals for preventing primary and secondary fractures: ensuring that patients admitted to the orthopedic department were promptly initiated on medication and identifying and initiating medication for patients admitted to other departments. METHODS: From April 2020 to March 2023, we analyzed the number of dual-energy X-ray absorptiometry (DEXA) scans performed, the DEXA rate among patients with proximal femoral fractures, and the rate of medication initiation each year. Our hospital implemented the FLS system in April 2022. It is a unique system utilizing admission screening form and osteoporosis educational appointments conducted by rehabilitation staff to initiate medication for orthopedic and non-orthopedic patients. RESULTS: The average monthly number of DEXA scans increased significantly, with 47.7 in 2020, 57.0 in 2021, and 90.8 in 2022. The DEXA rate among proximal femoral fracture patients increased from 23.3% in 2020 to 88.1% in 2021 and 100% in 2022. The rate of treatment initiation also increased remarkably, from 21.7% in 2020, to 68.7% in 2021, reaching 97.8% in 2022. We performed 504 interventions, resulting in 251 patients diagnosed with osteoporosis, of whom 134 (56 from non-orthopedic departments) successfully started medication. CONCLUSIONS: Our innovative FLS system, incorporating an admission screening form and osteoporosis educational appointments, proved effective in identifying patients with osteoporosis and facilitating medication initiation, which will prevent both primary and secondary fractures.

Treatment of ruptured rectal artery aneurysm in a patient with neurofibromatosis.

BACKGROUND: Superior rectal artery (SRA) aneurysms are rare. Although melena is the most common symptom, it has not been observed in cases of aneurysms located in the SRA trunk. Here, we report a case of a ruptured SRA trunk aneurysm successfully treated with coil embolization. Including our case, three of the four reported cases of SRA trunk aneurysms were related to neurofibromatosis type 1 (NF1). CASE PRESENTATION: A 52-year-old woman with NF1 was referred to our hospital for the investigation of an abdominal mass with back pain. She had previously undergone a blood transfusion at another hospital for anemia without melena. Computed tomography angiography revealed a ruptured SRA trunk aneurysm measuring 3 cm in diameter and surrounded by a retroperitoneal hematoma. The aneurysm was isolated by embolizing the SRA trunk distally and proximally. Distal embolization was performed retrogradely from the internal iliac artery (IIA) via the middle rectal artery (MRA)-SRA anastomosis because the antegrade approach from the inferior mesenteric artery (IMA) failed. To our knowledge, this is the first case of successful coil embolization of an IMA branch through the IIA. CONCLUSION: SRA trunk aneurysms are rare; however, they are frequently associated with NF1. Antegrade distal embolization beyond the aneurysm is sometimes difficult to achieve. In such cases, a retrograde approach via MRA-SRA anastomosis can be the choice for isolating SRA trunk aneurysms.

Relationship between hip joint proximity area and sagittal balance parameters: an upright computed tomography study.

PURPOSE: A close relationship between sagittal spinal alignment and hip osteoarthritis (OA) has been documented. This study aimed to examine the relationship between hip joint proximity area and sagittal balance parameters in healthy subjects. METHODS: This prospective study enrolled 47 healthy volunteers who underwent 320-detector row upright computed tomography. Acquired data were reconstructed in a virtual three-dimensional space. The proximity area was determined by < 1 mm of the Hausdorff distance between the acetabulum and the femoral head. Volunteers were divided into the anterior and posterior proximity groups depending on the position of the closest area. Sagittal balance parameters [sagittal vertical axis (SVA), T1 spinopelvic inclination (T1-SPi), T1-pelvic angle, pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, thoracic kyphosis), offset distance between the centre of the acoustic meati (CAM) and C7 plumb line (CAM-C7-offset), and offset distance between the CAM and hip axis (HA) (CAM-HA-offset)] were compared between the two groups using independent sample t test. RESULTS: The anterior proximity group (n = 24) had higher SVA (p = 0.016) and T1-Spi (p = 0.015) than the posterior proximity group (n = 23). CAM-HA-offset was higher in the posterior than in the anterior proximity group (p < 0.000). There was no difference in other parameters (p > 0.05). CONCLUSION: The anterior proximity group had a positive anterior spinal balance; the posterior proximity group may have a more posterior gravity line than the hip joint centre. The anterior spinal balance may contribute to the anterior loading of the hip joint, with known relation with the initiation and onset of hip OA.

Quantitative assessment of macular function after surgery for optic disc pit maculopathy: A case report.

RATIONALE: We describe a case of optic disc pit maculopathy (ODP-M) in which vitrectomy with juxtapapillary laser (JPL) treatment led to the reattachment of retinoschisis (RS) as well as serous retinal detachment (SRD). PATIENT CONCERNS: An 80-year-old man complained of distorted vision and decreased visual acuity (VA) in his left eye for 12 months. DIAGNOSIS: We conducted quantitative functional evaluation on the area of RS and SRD using the Humphrey visual field analyzer. Fundus examination and optical coherence tomography showed SRD and RS in connection with the optic disc. The best-corrected logarithm of the minimum angle of resolution (logMAR) VA was 0.7. INTERVENTIONS: The patient underwent JPL treatment combined with pars plana vitrectomy. During surgery, posterior vitreous detachment and tamponade were created with sulfur hexafluoride. OUTCOMES: After surgery, SRD (and subsequently RS) gradually reduced and had completely disappeared at 31 months. VA gradually improved and was 0.0 (logMAR) at 28 months. The analysis of the mean macular thickness of the central 3-mm diameter showed that the macula thickness recovered to 300 µm at 17 months postoperatively. Retinal sensitivity began to improve at 24 months postoperatively and had increased at 48 months postoperatively. LESSONS: In conclusion, vitrectomy with JPL treatment for ODP-M had a favorable anatomical outcome as well as a long-term functional outcome. These findings provide useful information for clinicians who are planning a therapeutic strategy, including the choice of surgical procedure for ODP-M.

Laser resonance frequency analysis of pedicle screw stability: A cadaveric model bone study.

There is no evaluation method currently available to assess intraoperative pedicle screw fixation (PSF) strength. In this study, we established a laser-based resonance frequency analysis (RFA) system with high-speed, noncontact, quantitative measurements of PSF. Clinical investigations in the future can assess surgical failure risk of implants. We investigated the characteristics of the laser RFA and compared them with the conventional methods. We inserted a pedicle screw in the vertebral pedicle of human cadaver or model bone, followed by screw pull-out, peak torque, implant stability quotient (ISQ) value obtained by the magnetic dental RFA system, and fixation force of laser RFA. We compared the outcomes using best-fit linear or logarithmic approximations. For the model bone study, the resonance frequency (RF) versus peak torque/pull-out force (POF) demonstrated strong correlations using logarithmic approximation (vs. peak torque: R = 0.931, p < .001, vs. POF: R = 0.931, p < .001). RF strongly correlated with the ISQ value using linear approximation (R = 0.981, p < .001). For the cadaveric vertebrae study, the correlation coefficients between RF and the peak torque/POF were significant regardless of approximation method (peak torque: logarithmic: R = 0.716 vs. linear: R = 0.811; p < .001) (POF: logarithmic: R = 0.644 vs. linear: R = 0.548; p < .05). Thus, the results of this study revealed a constant correlation between RFA and conventional methods as a measurement validation, predicting favorable support for intraoperative PSF. RFA has the potential to be a new index for evaluating the implant fixation force.

Carcinosarcoma of the ovary: MR and clinical findings compared with high-grade serous carcinoma.

PURPOSE: To clarify imaging and clinical characteristics of ovarian carcinosarcoma (CS) compared with high-grade serous carcinoma (HGSC). METHODS: We retrospectively reviewed MR imagings of 12 patients with CS and 30 patients with HGSC and evaluated tumor size, shape, appearance, nature of cystic and solid components, hemorrhage, and necrosis. Age, premenopausal or postmenopausal, histologic subtype, presence of endometriosis, tumor markers, and stage were also evaluated. These parameters were compared using the Mann-Whitney U test and the chi-square test/Fisher's exact test. RESULTS: The mean size of CSs was 13.6 cm, and significantly larger than that of HGSCs (mean 9.0 cm, p = 0.022). The stained-glass appearance (67% vs. 23%, p = 0.013), hemorrhage (100% vs. 50%, p = 0.003), necrosis (75.0% vs. 13%, p = 0.000), and endometriosis (33% vs. 7%, p = 0.012) were significantly more common in CSs. The postmenopausal ratio of CSs was 100% and significantly higher than that of HGSCs (70.0%, p = 0.041). Among the tumor makers, only CA-125 was significantly lower in CSs than in HGSCs (mean 715.1 U/ml vs. 1677.1 U/ml, p = 0.009). The stage distribution was similar and was not significantly different. CONCLUSION: CSs formed larger masses, and the stained-glass appearance, hemorrhage, and necrosis were more frequently observed in CSs.

Carrier proteins-based boron delivery to tumor.

The conjugation of maleimide-functionalized closo-dodecaborate (MID) to transferrin (TF), which has no free SH cysteine residue, proceeded at room temperature for 12 h in PBS buffer (pH = 7.4). MID-TF conjugates were accumulated into the cells in the time- and concentration-dependent manners through the TF receptor mediated mechanism. In vivo biodistribution study of MID-TF conjugates in colon 26-bearing mice revealed the time-dependent selective accumulation of MID-TF conjugates into tumor very similar to that of MID-BSA. The tumor boron concentration of MID-BSA was higher than that of MID-TF conjugates (62 ppm vs. 20 ppm at a dose of 30 mg [B]/kg) 12 h after administration, suggesting that the EPR effect is not remarkably observed in the case of MID-TF conjugates because TF has smaller molecular weight than BSA (48 kDa vs. 68 kDa).

Laser Resonance Frequency Analysis: A Novel Measurement Approach to Evaluate Acetabular Cup Stability During Surgery.

Artificial joint acetabular cup stability is essential for successful total hip arthroplasty. However, a quantitative evaluation approach for clinical use is lacking. We developed a resonance frequency analysis (RFA) system involving a laser system that is fully contactless. This study aimed to investigate the usefulness of laser RFA for evaluating acetabular cup stability. First, the finite element method was performed to determine the vibration mode for analysis. Second, the acetabular cup was press-fitted into a reamed polyurethane cavity that replicated the human acetabular roof. The implanted acetabular cup was vibrated with pulse laser irradiation and the induced vibration was detected with a laser Doppler vibrometer. The time domain signal from the vibrometer was analyzed by fast Fourier transform to obtain the vibration frequency spectrum. After laser RFA, the pull-down force of the acetabular cup was measured as conventional implant fixation strength. The frequency of the first highest amplitude between 2 kHz and 6 kHz was considered as the resonance peak frequency, and its relationship with the pull-down force was assessed. The peak frequency could predict the pull-down force (R2 = 0.859, p < 0.000). Our findings suggest that laser RFA might be useful to measure acetabular cup stability during surgery.

Angiographic Findings in Patients with Hepatocellular Carcinoma Previously Treated Using Proton Beam Therapy.

Given the growing interest in using proton beam therapy (PBT) for hepatocellular carcinoma (HCC), it is possible that transarterial chemoembolization (TACE) could be used for selected patients who have previously undergone PBT. However, these cases can be technically challenging to treat and require appropriate preparation. Thus, we aimed to identify angiographic findings in this setting. We retrospectively identified 31 patients (28 men and 3 women, mean age: 69 years, range: 43-84 years) who underwent hepatic angiography plus TACE or transarterial infusion chemotherapy (TAI) for HCC that recurred after PBT (July 2007 to June 2018). We discovered four angiographic findings, which we speculate were related to the previous PBT. 18 patients experienced recurrence in the irradiated field, and 13 patients experienced recurrence outside the irradiated field. 29 patients underwent TACE and only 2 patients underwent TAI. The mean number of previous PBT treatments was 1.3 ± 0.6 (range: 1-4). The median interval from the earliest PBT treatment to hepatic angiography was 559 days (range: 34-5,383 days), and the median interval from the latest PBT treatment to hepatic angiography was 464 days (range: 34-5,383 days). Abnormal staining of the irradiated liver parenchyma was observed in 22 patients, which obscured the angiographic tumor staining in 4 patients. Development of a tortuous tumor feeder vessel was observed in 13 patients. Development of an extrahepatic collateral pathway was observed in 7 patients. Development of an arterioportal or arteriovenous shunt was observed in 4 patients. Based on these findings, we conclude that PBT was associated with various angiographic findings during subsequent transarterial chemotherapy for recurrent HCC, and familiarity with these findings will be important in developing appropriate treatment plans.

Successful transarterial embolization of coronary artery fistula with ruptured aneurysm: A case report.

We report a case of a coronary artery fistula (CAF) with ruptured aneurysm treated using transarterial embolization (TAE) alone. The ruptured aneurysm caused cardiac tamponade, and it was isolated by embolizing its afferent and efferent vessels using detachable coils. To our knowledge, this is the first case report of successful TAE for a CAF with ruptured aneurysm. We believe that if the patient condition is stable and the CAF is anatomically simple, TAE can be a less-invasive alternative to surgery.

Ultrasound imaging of the anorectal malformation during the neonatal period: a comprehensive review.

Anorectal malformation (ARM) is classified as low, intermediate, or high; accurate diagnosis of the type during the early neonatal period is important to determine the appropriate initial surgical approach. This review assesses the role of ultrasound examination in the classification of ARM during the neonatal period, with a focus on landmarks on the sonogram, the approach used for sonography, and the optimal examination timing. The following three factors on the sonogram are used for the classification: location of the fistula, the distance between the distal rectal pouch and the anal dimple (perineum) (P-P distance), and the relationship between the puborectalis muscle and the distal rectal pouch. Three approaches can be used to evaluate ARM by ultrasonography, namely, suprapubic, perineal, and infracoccygeal approaches. Each approach has its own advantages and disadvantages. Optimal timing of the ultrasound examination is also important with respect to each factor to classify ARM. We have described the pitfalls of ultrasound in diagnosis of cases, namely ARM with Down syndrome (which tends to be without fistula), ARM with low birth weight, ARM with unusual location of fistula, ARM with opened fistula (where the P-P distance is unreliable), and cloacal malformation (variation of the high-type ARM).

Maleimide-functionalized closo-dodecaborate albumin conjugates (MID-AC): Unique ligation at cysteine and lysine residues enables efficient boron delivery to tumor for neutron capture therapy.

Maleimide-conjugating closo-dodecaborate sodium form 5c (MID) synthesized by the nucleophilic ring-opening reaction of closo-dodecaborate-1,4-dioxane complex 2 with tetrabutylammonium (TBA) azide was found to conjugate to free SH of cysteine and lysine residues in BSA under physiological conditions, forming highly boronated BSA that showed high and selective accumulation in tumor and significant tumor growth inhibition in colon 26 tumor-bearing mice subjected to thermal neutron irradiation.

[Prolonged psychosis associated with thyrotoxicosis during the subacute stage of cardioembolic stroke in a patient with untreated basedow disease].

A 57-year-old female developed dizziness and forgetfulness several days before admission. She was admitted to our hospital because of a headache and nausea. On admission, she had a mild disturbance of consciousness and right hemiparesis. Initial MR imaging revealed multiple infarctions in the acute-to-subacute phases in the right cerebellum, left occipital lobe, and bilateral parietal lobes. Her electrocardiogram showed atrial fibrillation and transesophageal echocardiography revealed the presence of a thrombus at the left atrial appendage, suggesting that she suffered from cardioembolic stroke. Laboratory testing showed elevated free T4 levels and low thyroid stimulating hormone (TSH) levels with positive anti-TSH receptor antibodies, indicating untreated Basedow disease. Although treatment with anticoagulants and methimazole was initiated, her postural tremor, tachycardia, and psychosis deteriorated. On the 8th day of admission, thyrotoxic crisis was confirmed. Despite increased doses of methimazole, as well as treatments with inorganic iodine, steroids, and ß-blockers, her psychosis prolonged even after her thyroid function was normalized. Long-term use of antipsychotic medications was required to treat her psychosis. In this case, neurotoxicity of the anti-TSH antibodies related to Basedow disease may have caused prolonged psychosis because of the extensive damage to the blood-brain-barrier function following multiple ischemic strokes. Careful observation and treatment are required for psychotic symptoms, in addition to the treatment for acute stroke in such cases, where thyrotoxic crisis is associated with ischemic stroke.

Asymmetric synthesis of 2,5-disubstituted 3-hydroxypyrrolidines based on stereodivergent intramolecular iridium-catalyzed allylic aminations.

Intramolecular iridium-catalyzed allylic aminations of homochiral (E)-6-N-nosylaminohept-2-en-1-yl methyl carbonates were investigated. The relative position of the 2,5-substituents of the resulting pyrrolidines was found to be controlled by using both enantiomers (4 and 5) of the appropriate chiral ligand, demonstrating a simple and highly stereodivergent synthetic protocol. Selected trans- and cis-2,5-disubstituted 3-hydroxypyrrolidines (2a and 18a) were converted to (+)-bulgecinine (6) and (+)-preussin (7), respectively.

Transcriptome map of plant mitochondria reveals islands of unexpected transcribed regions.

BACKGROUND: Plant mitochondria contain a relatively large amount of genetic information, suggesting that their functional regulation may not be as straightforward as that of metazoans. We used a genomic tiling array to draw a transcriptomic atlas of Oryza sativa japonica (rice) mitochondria, which was predicted to be approximately 490-kb long. RESULTS: Whereas statistical analysis verified the transcription of all previously known functional genes such as the ones related to oxidative phosphorylation, a similar extent of RNA expression was frequently observed in the inter-genic regions where none of the previously annotated genes are located. The newly identified open reading frames (ORFs) predicted in these transcribed inter-genic regions were generally not conserved among flowering plant species, suggesting that these ORFs did not play a role in mitochondrial principal functions. We also identified two partial fragments of retrotransposon sequences as being transcribed in rice mitochondria. CONCLUSION: The present study indicated the previously unexpected complexity of plant mitochondrial RNA metabolism. Our transcriptomic data (Oryza sativa Mitochondrial rna Expression Server: OsMES) is publicly accessible at [http://bioinf.mind.meiji.ac.jp/cgi-bin/gbrowse/OsMes/#search].

Distinct gene expression profiles in egg and synergid cells of rice as revealed by cell type-specific microarrays.

Double fertilization in flowering plants refers to a process in which two sperm cells, carried by the pollen tube, fertilize both the egg and the central cell after their release into a synergid cell of the female gametophyte. The molecular processes by which the female gametophytic cells express their unique functions during fertilization are not well understood. Genes expressed in egg and synergid cells might be important for multiple stages of the plant reproductive process. Here, we profiled genome-wide gene expression in egg and synergid cells in rice (Oryza sativa), a model monocot, using a nonenzymatic cell isolation technique. We found that the expression profiles of the egg and synergid cells were already specified at the micropylar end of the female gametophyte during the short developmental period that comprises the three consecutive mitotic nuclear divisions after megaspore generation. In addition, we identified a large number of genes expressed in the rice egg and synergid cells and characterized these genes using Gene Ontology analysis. The analysis suggested that epigenetic and posttranscriptional regulatory mechanisms are involved in the specification and/or maintenance of these cells. Comparisons between the rice profiles and reported Arabidopsis (Arabidopsis thaliana) profiles revealed that genes enriched in the egg/synergid cell of rice were distinct from those in Arabidopsis.

OryzaExpress: an integrated database of gene expression networks and omics annotations in rice.

Similarity of gene expression profiles provides important clues for understanding the biological functions of genes, biological processes and metabolic pathways related to genes. A gene expression network (GEN) is an ideal choice to grasp such expression profile similarities among genes simultaneously. For GEN construction, the Pearson correlation coefficient (PCC) has been widely used as an index to evaluate the similarities of expression profiles for gene pairs. However, calculation of PCCs for all gene pairs requires large amounts of both time and computer resources. Based on correspondence analysis, we developed a new method for GEN construction, which takes minimal time even for large-scale expression data with general computational circumstances. Moreover, our method requires no prior parameters to remove sample redundancies in the data set. Using the new method, we constructed rice GENs from large-scale microarray data stored in a public database. We then collected and integrated various principal rice omics annotations in public and distinct databases. The integrated information contains annotations of genome, transcriptome and metabolic pathways. We thus developed the integrated database OryzaExpress for browsing GENs with an interactive and graphical viewer and principal omics annotations (http://riceball.lab.nig.ac.jp/oryzaexpress/). With integration of Arabidopsis GEN data from ATTED-II, OryzaExpress also allows us to compare GENs between rice and Arabidopsis. Thus, OryzaExpress is a comprehensive rice database that exploits powerful omics approaches from all perspectives in plant science and leads to systems biology.

Rice expression atlas in reproductive development.

Gene expression throughout the reproductive process in rice (Oryza sativa) beginning with primordia development through pollination/fertilization to zygote formation was analyzed. We analyzed 25 stages/organs of rice reproductive development including early microsporogenesis stages with 57,381 probe sets, and identified around 26,000 expressed probe sets in each stage. Fine dissection of 25 reproductive stages/organs combined with detailed microarray profiling revealed dramatic, coordinated and finely tuned changes in gene expression. A decrease in expressed genes in the pollen maturation process was observed in a similar way with Arabidopsis and maize. An almost equal number of ab initio predicted genes and cloned genes which appeared or disappeared coordinated with developmental stage progression. A large number of organ-/stage-specific genes were identified; notably 2,593 probe sets for developing anther, including 932 probe sets corresponding to ab initio predicted genes. Analysis of cell cycle-related genes revealed that several cyclin-dependent kinases (CDKs), cyclins and components of SCF E3 ubiquitin ligase complexes were expressed specifically in reproductive organs. Cell wall biosynthesis or degradation protein genes and transcription factor genes expressed specifically in reproductive stages were also newly identified. Rice genes homologous to reproduction-related genes in other plants showed expression profiles both consistent and inconsistent with their predicted functions. The rice reproductive expression atlas is likely to be the most extensive and most comprehensive data set available, indispensable for unraveling functions of many specific genes in plant reproductive processes that have not yet been thoroughly analyzed.

Morphological and gene expression analysis under cool temperature conditions in rice anther development.

Cool temperature conditions are known to lead to pollen sterility in rice. Pollen sterility is an agriculturally important phenomenon because it imparts a large influence directly on rice yield. However, cool temperature stress tolerance varies among rice cultivars and avoidance of cool temperature stress is difficult by practical method of agriculture. In this study using two rice cultivars, Hitomebore (high tolerance) and Sasanishiki (low tolerance), we analyzed morphological features and gene expression profiles, under cool temperature stress, in anther development of rice. Hitomebore was given cool temperature stress (19 degrees C) at flowering stage, and showed 87.3% seed fertility. Meanwhile, the seed fertility decreased to 41.7% in the case of Sasanishiki. A transverse section of Hitomebore anther revealed that the degradation of the tapetum started at the uninucleate microspore stage, and the tapetum had completely vanished at mature stage. The tapetum provides nutrients for pollen development, and its degradation occurs at a late stage in pollen development. In contrast, degradation of the tapetum did not occur at the uninucleate microspore stage in Sasanishiki, and the tapetum was clearly intact at mature stage, suggesting that tapetum degradation is critical for accurate pollen development and cool temperature tolerance correlated with the degree of tapetum degeneration. In gene expression analysis of anther, 356 genes that showed different expression levels between two cultivars at cool temperatures were found. These genes will lead to understanding the mechanism of cool temperature stress response in rice pollen development and the identification of genes involved in accurate tapetum degradation.

Various spatiotemporal expression profiles of anther-expressed genes in rice.

The male gametophyte and tapetum play different roles during anther development although they are differentiated from the same cell lineage, the L2 layer. Until now, it has not been possible to delineate their transcriptomes due to technical difficulties in separating the two cell types. In the present study, we characterized the separated transcriptomes of the rice microspore/pollen and tapetum using laser microdissection (LM)-mediated microarray. Spatiotemporal expression patterns of 28,141 anther-expressed genes were classified into 20 clusters, which contained 3,468 (12.3%) anther-enriched genes. In some clusters, synchronous gene expression in the microspore and tapetum at the same developmental stage was observed as a novel characteristic of the anther transcriptome. Noteworthy expression patterns are discussed in connection with gene ontology (GO) categories and gene annotations, which are related to important biological events in anther development, such as pollen maturation, pollen germination, pollen tube elongation and pollen wall formation.