Selective Suppression of Pathologic, but Not Physiologic, Retinal Neovascularization by Blocking the Angiotensin II Type 1 Receptor

PURPOSE

To investigate the anti-inflammatory and anti-angiogenic effects of telmisartan, an angiotensin II type 1 receptor (AT1-R) antagonist, on ischemia-induced retinal neovascularization.

METHODS

C57BL/6 neonatal mice were reared in an 80% concentration of oxygen from postnatal day (P)7 to P12, followed by room-air breathing until P17, to induce ischemia-initiated retinal neovascularization (i.e., a murine model of ischemic retinopathy). Tissue localization of AT1-R was examined by immunohistochemistry for murine retinal wholemounts and human fibrovascular tissues excised at vitrectomy for proliferative diabetic retinopathy. Animals received intraperitoneal injection of telmisartan or vehicle. A concanavalin A lectin perfusion-labeling technique was used to evaluate the areas of physiological and pathologic retinal new vessels and the number of leukocytes adhering to the vasculature. Retinal mRNA and protein levels of intercellular adhesion molecule (ICAM)-1, vascular endothelial growth factor receptor (VEGFR)-1, and VEGFR-2 were examined by RT-PCR and ELISA.

RESULTS

Vessels in human fibrovascular tissues and the murine retinas were positive for AT1-R. Pathologic (P < 0.01), but not physiologic (P > 0.05), retinal neovascularization was significantly suppressed in telmisartan-treated mice compared with vehicle-treated animals. The number of adherent leukocytes (P < 0.01) was also significantly reduced, together with retinal ICAM-1 levels (P < 0.01) in the telmisartan-treated group compared with the control group. No significant difference was detected in retinal VEGFR-2 levels between the two groups, whereas retinal VEGFR-1 levels in the telmisartan-treated group were significantly (P < 0.05) lower than in the vehicle-treated group.

CONCLUSIONS

The present findings suggest that the AT1-R signaling blockade leads to the selective suppression of pathologic, but not physiological, retinal neovascularization through the inhibition of the inflammatory processes related to pathologic neovascularization.

Expression of Notch in a case of osteosarcoma of the maxilla

In this immunohistochemical examination, the expression of Notch1 peptide was detected in neoplastic cells in a case of osteosarcoma of the maxilla of a 31-year-old Indonesian male patient. Notch1 peptide appeared in the cytoplasm of neoplastic cells of comparatively well-differentiated areas of the osteosarcoma, an osteoblastic area containing osteoid and/or immature bone tissues. The results suggest that Notch1 is closely related to cytological differentiation or acquisition of cytological characteristics in neoplastic cells of osteosarcoma.

Intraoperative breakage of a 25-gauge vitreous cutter

PURPOSE

To report breakage of a 25-gauge vitreous cutter during vitreous surgery.

DESIGN

Interventional case report.

METHODS

A 60-year-old woman was referred for management of an epiretinal membrane at the macula. Visual acuity was 20/100 in the affected left eye. Vitreous surgery using a 25-gauge vitrectomy system was carried out with a combination of conventional cataract surgery.

RESULTS

The vitreous cutter was lodged within the sclerotomy cannula after peripheral vitrectomy and was pulled together with the cannula. The cannula was reinserted by trocar, but as the floating peeled epiretinal membrane was dissected with the vitreous cutter, the tip of the cutter was broken and was aspirated with the membrane. Stereoscopic microscopy and scanning electron microscopy demonstrated that the edge that had broken at the cutter port was smooth.

CONCLUSION

Although 25-gauge instruments remain useful, care should be taken against rare surgical complications related to their fragility.

Comparative effects of microplasmin and tissue-type plasminogen activator (tPA) on cerebral hemorrhage in a middle cerebral artery occlusion model in mice

BACKGROUND

Thrombolytic therapy of ischemic stroke with tissue-type plasminogen activator (tPA) improves clinical outcome which may, however, be partially offset by significant intracerebral bleeding (ICB).

OBJECTS

The comparative effects of microplasmin (microPli) and tPA on ICB were evaluated in a thrombotic middle cerebral artery (MCA) occlusion model in mice.

METHODS

A dose of microPli (5 mg kg(-1)) or tPA (4 mg kg(-1)) which are comparably effective for reduction of brain damage, or a double dose (10 or 8 mg kg(-1), respectively) or the microPli excipient as a control were intravenously administered as a bolus at 30 min or 4 h after MCA occlusion. ICB was measured at 24 h by hemoglobin assay of exsanguinated brain extracts. Bleeding time was measured by tail cutting.

RESULTS

In controls given solvent at 4 h, ICB was on average 8.8 micro L, which was significantly increased with 10 mg kg(-1) microPli and with 4 and 8 mg kg(-1) tPA to 12-13 micro L (P < 0.05 each vs. controls, n = 7-9), whereas 5 mg kg(-1) microPli did not affect bleeding (8.5 micro L P = NS vs. controls, n = 7). When given at 30 min, neither microPli nor tPA altered ICB (6.3-6.8 micro L, mean; n = 7-9). tPA but not microPli increased bleeding time; from 2.4 min in controls to 5.9 min (median, P < 0.05 vs. controls) and 8.7 min (P < 0.01 vs. controls) with 4 and 8 mg kg(-1), respectively, and to 2.3 and 2.9 min with 5 and 10 mg kg(-1) microPli, respectively (n = 10).

CONCLUSIONS

microPli at a dose comparably effective as tPA for brain damage reduction induced significantly less ICB, and less bleeding time prolongation in mice with thrombotic MCA occlusion.

Successful treatment of subfoveal choroidal neovascularization associated with combined hamartoma of the retina and retinal pigment epithelium

PURPOSE

To describe a patient with subfoveal choroidal neovascularization (CNV) associated with combined hamartoma of the retina and retinal pigment epithelium (CHRRPE), treated successfully by submacular surgery.

DESIGN

Interventional case report.

METHODS

A 12-year-old girl was referred to our clinic for evaluation. Visual acuity was 20/30 in the affected left eye. Ophthalmoscopy disclosed juxtapapillary CHRRPE and subfoveal pigmented CNV. Vitreous surgery was carried out because of visual deterioration to 20/60.

RESULTS

The posterior vitreous was strongly attached to glial tissue at the superior margin of the optic disk in the CHRRPE region. The CNV, which was not connected with the CHRRPE, was carefully removed, resulting in visual improvement to 20/20 5 months after surgery. Histologically, the excised membrane showed fibroblast-rich cellular component and a type 2 configuration.

CONCLUSION

Submacular surgery can be effective for the treatment of secondary CNV associated with CHRRPE.

Expression of osteoclast differentiation factor and osteoclastogenesis inhibitory factor in rat osteoporosis induced by immunosuppressant FK506

Immunosuppressant drugs are currently required by transplant recipients for the remainder of their lives, despite the many adverse effects associated with these therapies. Acute osteoporosis is one such effect, and a reproducible osteoporosis model has been established through the administration of the immunosuppressant drug FK506 in rats. The cause of this osteoporosis has been shown to be abnormal osteoclast proliferation, altering the process of bone remodeling. However, the reasons why FK506 induces osteoclast proliferation and whether this process is mediated by cytokine changes or an increase in bone resorption factors have been unclear. An investigation was therefore conducted focusing on the recent discoveries of osteoclast differentiation factor (ODF) and osteoclastogenesis inhibitory factor (OCIF). These factors led to elucidation of the osteoclast differentiation-maturation mechanism. An osteoporosis model was produced in rats utilizing intramuscular FK506 injection (1 mg/kg) for 28 consecutive days. Trabecular bone resorption was observed inferior to enchondral ossification in the FK506 group, and tartrate resistant acid phosphatase (TRAP) staining revealed a clear increase in osteoclasts at the site of enchondral ossification, relative to the control group. Real-time PCR and in situ hybridization (ISH) demonstrated minimal differences in OCIF expression between control and the treatment groups. However, Real-time PCR revealed clearly increased ODF expression in the treatment group. ODF expression was also shown to be increased in the treatment group using ISH. This was histologically consistent with a region of osteoclast proliferation inferior to enchondral ossification. The results of this study support the hypothesis that FK506-mediated osteoporosis occurs by action of the drug on osteoclasts, promoting expression of ODF messenger ribonucleic acid (mRNA) and thus prompting osteoclast differentiation and maturation.

[Intravitreal injection of triamcinolone acetonide for cystoid macular edema resistant to vitreous surgery]

PURPOSE

To report the efficacy of intravitreal injection of triamcinolone acetonide(TA) for cystoid macular edema remaining after vitreous surgery.

METHODS

Eight eyes of 7 patients aged from 32 to 84 years old were studied. The original diseases that caused macular edema were central retinal vein occlusion in 2 eyes, branch retinal vein occlusion in one eye, Irvine-Gass syndrome in 2 eyes, and diabetic retinopathy in 3 eyes. 4 mg of TA was injected intravitreally and visual acuity and foveal thickness measured by optical coherence tomography(OCT) were evaluated in before and after the surgery.

RESULTS

Macular edema resolved rapidly after injection of TA in all cases and cysts were extinguished or diminished. The foveal thickness in OCT was reduced significantly from preoperative 495 +/- 116 (mean +/- standard deviation) microns to 267 +/- 117 microns after one week, and 246 +/- 81 microns after one month. The effect persisted for three months. Visual improvement of more than two Snellen lines was seen in 4 eyes. No side effects were observed except a temporary increase of intraocular pressure in one eye.

CONCLUSION

Intravitreal injection of TA is effective in a short-term for cystoid macular edema remaining after vitrectomy.

Effect of physical activity on autonomic nervous system function in lean and obese children

OBJECTIVE

The autonomic nervous system (ANS) is a key factor in the regulation of energy balance and body fat storage;however, to what extent the physical activity during the childhood years contributes to variations in ANS function is still unclear. The present study was designed to investigate the ANS activity in lean and obese children, focusing on the differences in physical activity levels.

SUBJECTS

This study was performed on 1080 school children initially recruited to the present study. In all, 24 physically active and 24 inactive obese children (> or =120% of the standard body weight) were chosen as samples. Then, 24 lean-active and 24 lean-inactive children, who were matched individually in age, gender, height, and the amount of sports activity, were carefully selected from the remaining children.

MEASUREMENTS

Physical activity was classified as the frequency of participation in after-school sports activities (active; > or =3 times per week, inactive; nothing). The ANS activities were measured during the resting condition by means of heart rate (HR) variability power spectral analysis, which enables us to identify separate frequency components, that is, low frequency (LF; 0.03-0.15 Hz), reflecting mixed sympathetic (SNS) and parasympathetic nervous system (PNS) activity, high frequency (HF; 0.15-0.5 Hz), mainly associated with PNS activity, and total power (TP; 0.03-0.5 Hz), evaluating the overall ANS activity. The spectral powers were log transformed for statistical testing.

RESULTS

The lean-active group demonstrated lower resting HR as well as significantly higher TP, LF, and HF powers compared to the remaining groups. In contrast, the obese-inactive group showed significantly lower TP (P<0.05 vs the remaining groups), LF (P<0.05 vs the lean groups), and HF power (P<0.05 vs the lean groups), respectively. The obese-active and lean-inactive groups were nearly identical in all spectral parameters. The correlation analysis revealed that TP among 48 inactive children was significantly and negatively associated with the percentage of body fat (r=-0.53, P<0.001); however, such correlation among 48 active children was modest (r=-0.33, P=0.02).

CONCLUSION

Our data suggest that obese children possess reduced sympathetic as well as parasympathetic nervous activities as compared to lean children who have similar physical activity levels. Such autonomic reduction, associated with the amount of body fat in inactive state, might be an etiological factor of onset or development of childhood obesity. On the other hand, regular physical activities could contribute to enhance the overall ANS activity in both lean and obese children. These findings further imply that regular physical activity might be effective in preventing and treating obesity beginning in the childhood.

Gene expression of type I collagen in neoplastic chondrocytes

In the present examination, we detected type I collagen mRNA in neoplastic chondrocytes in osteochondromas, typical benign bone neoplasms. We believe that the cells involved in >chondroid bone< appearing in osteochondromas temporally express cartilage phenotypes and then change directly into bone-forming cells that survive in the >chondroid bone< until the tissue is resorbed and remodelled into true bone tissue.

Recombinant human microplasmin: production and potential therapeutic properties

The effect of recombinant human microplasmin was studied in ischemic stroke models in mice and in an extracorporeal loop thrombosis model in rabbits. Human microplasminogen ( micro Plg), which lacks the five 'kringle' domains of plasminogen was expressed with high yield in Pichia pastoris. It was purified, converted to microplasmin ( micro Pli) and equilibrated with 5 mmol L(-1) citrate, pH 3.1, yielding a stable preparation. In mice with middle cerebral artery (MCA) ligation, an intravenous (i.v.) bolus of 5.0 mg kg(-1) micro Pli reduced infarct size at 24 h from 27 (26-30) to 25 (21-28) mm3 (median and range, n= 16 each, P= 0.0001), whereas 4.0 mg kg(-1) rt-PA and 40 mg kg(-1) micro Plg had no effect. Infarct reduction was observed with administration at 4 h after occlusion. In mice with MCA, infarct size at 24 h was reduced from 20 (14-30) to 9.1 (3.1-25) mm3 with 5.0 mg kg(-1) micro Pli (n = 15 each, P < 0.002) and to 11 (5.2-27) mm3 with 4.0 mg kg(-1) rt-PA (n = 6; P= 0.02). Infarct reduction was still observed at 10 h after occlusion with micro Pli but not with t-PA. In rabbits with radiolabeled clots in an extracorporeal arteriovenous loop, local infusion of 2.5 mg kg(-1) micro Pli over 2 h, induced 51 +/- 15% lysis (mean +/- SD, n= 11) vs. a control value of 23 +/- 5.5%. micro Pli did not prolong template bleeding times, whereas equipotent doses of rt-PA were associated with extensive rebleeding. The potency of micro Pli in both models was similar to that of intact plasmin. These findings indicate that recombinant micro Pli may be useful for treatment of ischemic stroke and arterial thrombosis.

Rapid, specific and active site-catalyzed effect of tissue-plasminogen activator on hippocampus-dependent learning in mice

In the present study we trained tissue-plasminogen activator (tPA)-knockout (tPA -/-) and wild-type (tPA +/+) male mice in step-down inhibitory avoidance learning, a hippocampus-dependent task. tPA -/- displayed significantly shorter latencies to step down at 90 min, one, two and seven days after training indicating the learning deficit in these animals (P < 0.05 vs tPA +/+). The locomotor activity, the level of anxiety in an elevated-plus maze, as well as the pain threshold did not differ between the two strains of mice. The learning disability of tPA -/- was overcome by more intense training. The learning deficit was also partially restored by limited intrahippocampal delivery of tPA (infused for 2 h before training; P < 0.05 vs control), but not by the delivery of urokinase plasminogen activator, indicating the acute need for tPA in learning. The beneficial effect of tPA was abolished by co-infusion of its inhibitor tPA-STOP, indicating that the facilitatory effect of tPA on learning requires a proteolytic step. However, tPA activity in the hippocampus was not indispensable for effective memory retrieval in tPA-infused tPA -/- mice. Thus, rapid, specific and proteolytic action of tPA facilitates hippocampus-dependent learning, but not retrieval of previously acquired information.

p27, cyclin E, and CDK2 expression in normal and cancerous endometrium

The objective was to investigate the immunohistochemical expression of p27, cyclin E, and CDK2 in normal and cancerous endometrium. Expression of p27 in premenopausal normal endometrium was significantly higher than that in postmenopausal normal endometrium (p=0.019). A significantly lower amount of p27 staining was observed in endometrial cancer tissues from premenopausal women than in normal premenopausal endometrium (p=0.015). Cyclin E expression in premenopausal normal endometrium was significantly higher than that in postmenopausal normal endometrium (p=0.003). A significantly higher amount of cyclin E staining was observed in endometrial cancer tissues from postmenopausal women than in normal postmenopausal endometrium (p=0.017). Regarding menopausal status, no significant difference in CDK2 staining was observed between cancerous and normal endometrium. There was a positive significant correlation between cyclin E and CDK2 expression levels in endometrial cancers (p<0.05). Western blot analysis confirmed elevated p27 protein levels in samples with positive p27 immunostaining. Considerable levels of p27 mRNA were detected in all normal and cancerous samples examined by semi-quantitative PCR. No significant relationship was found between telomerase activity and its association with p27 and cyclin E expression in endometrial cancers. These findings suggested that the decreased expression of p27 caused by post-translational mechanism might play an important role in endometrial cancer development in premenopausal women. In addition, increased cyclin E expression may play an important role in endometrial cancer development in postmenopausal women.

The expression of dentin sialophosphoprotein gene in bone

Dentin sialoprotein (DSP) and dentin phosphoprotein (DPP) are expressed as a single mRNA transcript coding for a large precursor protein termed dentin sialophosphoprotein (DSPP). DSP, DPP, and DSPP have been considered to be tooth-specific. To test for the expression of the dspp gene in bone, we performed Western immunoblots and reverse-transcription polymerase chain-reaction (RT-PCR). With Western immunoblots, we detected DSP in the Gdm/EDTA extracts of rat long bone, at a level of about 1/400 of that in dentin. Using RT-PCR, we detected DSPP mRNA in mouse calvaria. Similar to Western immunoblots, the results of RT-PCR indicated that the dspp gene is expressed at a lower level in bone than in dentin and odontoblasts. Analysis of the data shows that DSPP is not a tooth-specific protein, and that dramatically different regulatory mechanisms governing DSPP expression are involved in the bone and dentin.

Evaluation of mitogen-induced responses in marine mammal and human lymphocytes by in-vitro exposure of butyltins and non-ortho coplanar PCBs

The effects of exposure to butyltin compounds (BTs: tributyltin; TBT, dibutyltin; DBT and monobutyltin; MBT) and non-ortho coplanar PCBs (IUPAC 77, 126 and 169) on marine mammals and human lymphocyte were evaluated. Peripheral blood mononuclear cells (PBMCs) isolated from Dall's porpoises (Phocoenoides dalli), bottlenose dolphins (Tursiops truncatus), a California sealion (Zalophus californianus), a larga seal (Phocoa largha) and humans (Homo sapiens) were exposed at varying concentrations of BTs and coplanar PCBs. Concanavalin A (Con A)-stimulated mitogenesis found significantly suppressed (P<0.01) when the cells were exposed at 300 nM (89 ng/ml) of TBT and 330 nM of DBT (77 ng/ml), while MBT showed little cytotoxicity at treatment levels of up to 3,600 nM (620 ng/ml). BTs concentrations in the liver of Dall's porpoises from Japanese coastal waters ranged between 81-450 ng/g for TBT and 200-1,100 ng/g (wet wt.) for DBTs, which is greater than the cytotoxic levels registered in this study. In contrast, non-ortho coplanar PCBs did not suppress cell proliferation at concentrations of up to 30 nM (10 ng/ml). The residue levels of coplanar PCBs in the blubber of Dall's porpoises were 0.12-1.3 ng/g, which were one order of lower than those levels that do cell proliferation. When cells were exposed to a mixture of TBT/DBTand coplanar PCBs, the proliferation was significantly reduced to 33 nM DBT plus 34 nM CB-77 and 33 nM DBT plus 28 nM CB-169 mixtures, respectively. The investigations relating the contaminant-induced immunosuppression in marine mammals have been focused on persistent organochlorines such as PCBs. pesticides and dioxin compounds. However, this study suggested the possibility of BTs could also pose a serious threat to the immune functions in free-ranging marine mammals and humans.

Characteristics of bone morphogenetic protein-induced chondroid bone: histochemical, immunohistochemical and in situ hybridization examinations

The third ossification mode, known as transchondroid bone formation, is displayed chiefly in the bone morphogenetic protein (BMP)-induced heterotopic bone formation model. This paper describes the results of histopathological, histochemical, immunohistochemical, and in situ hybridization examinations of BMP-induced heterotopic bone in mice. The research focuses on the localization of typical matrix proteins (peptide and its mRNA) of cartilage and bone--type-I and type-II collagen, osteocalcin and osteopontin--in the chondroid bone matrix.

Localization of type IV collagen a 1 to a 6 chains in basement membrane during mouse molar germ development

The dental basement membrane (BM) putatively mediates epithelial-mesenchymal interactions during tooth morphogenesis and cytodifferentiation. Type IV collagen alpha chains, a major network-forming protein of the dental BM, was studied and results disclosed distinct expression patterns at different stages of mouse molar germ development. At the dental placode and bud stage, the BM of the oral epithelium expressed alpha 1, alpha 2, alpha 5 and alpha 6 chains while the gubernaculum dentis, in addition to the above four chains, also expressed a 4 chain. An asymmetrical expression for alpha 4, alpha 5 and alpha 6 chains was observed at the bud stage. At the early bell stage, the BM associated with the inner enamel epithelium (IEE) of molar germ expressed alpha 1, alpha 2 and alpha 4 chains while the BM of the outer enamel epithelium (OEE) expressed only alpha 1 and a 2 chains. With the onset of dentinogenesis, the collagen a chain profile of the IEE BM gradually disappeared. Howeverfrom the early to late bell stage, the gubernaculum dentis consistently expressed alpha 1, alpha 2, alpha 5 and a 6 chains resembling fetal oral mucosa. These findings suggest that stage- and position-specific distribution of type IV collagen alpha subunits occur during molar germ development and that these changes are essential for molar morphogenesis and cytodifferentiation.

Prognostic significance of p27 and Ki-67 expression in mucoepidermoid carcinoma of the intraoral minor salivary gland

p27 and Ki-67, a universal cyclin-dependent kinase inhibitor and a proliferative cell marker, respectively, have been useful in predicting clinical aggressiveness in various human tumors. We studied clinicopathologic significance of these molecules in mucoepidermoid carcinoma of the intraoral minor salivary gland. Expression of p27 and Ki-67 was assessed immunohistochemically in primary mucoepidermoid carcinomas from 31 patients without distant metastasis at surgery. Correlation each of p27 and Ki-67 expression was analyzed with various clinicopathologic parameters including age, sex, primary tumor site, tumor size, nodal metastasis, clinical stage, and histologic grade. The latter was evaluated using a point-scoring scheme of Auclair et al. that consists of five histologic factors (intracystic component, neural invasion, necrosis, mitosis, and anaplasia). p27 expression was correlated inversely with histologic grade (P =.007), but with none of other factors. When the correlation of p27 expression was further examined with each of the histologic factors, it was correlated significantly with intracystic component, but not with neural invasion, necrosis, mitosis, or anaplasia. Ki-67 expression was correlated significantly with histologic grade only in the clinicopathologic factors (P <.0001), and in the histologic factors, with necrosis, mitosis, and anaplasia. Multivariate prognostic analyses were performed to identify independent risk factors for both disease-free and overall survivals. Large tumor size (P =.031, relative risk = 5.5) and low p27 expression (P =.012, relative risk = 5.2) were risk factors for worse disease-free survival. Low p27 expression (P =.015, relative risk = 15.2) was selected as a risk factor for worse overall survival. Other factors including age, sex, tumor site, nodal status, clinical stage, histologic grade, and Ki-67 did not emerge as independent risk factors in either prognostic analysis. These data suggest that p27 may be useful in estimating prognosis of the patients who have mucoepidermoid carcinoma of the intraoral minor salivary gland.

Quantitation of epidermal growth factor receptor gene amplification by competitive polymerase chain reaction in pre-malignant and malignant oral epithelial lesions

Abnormal amplification of epidermal growth factor receptor (EGFR) gene has been reported widely in various human tumors. However, the status of amplification of this gene in the process of carcinogenesis is not clearly defined. We used competitive polymerase chain reaction (PCR) to study whether EGFR gene is amplified and the degree of amplification in pre-malignant and malignant oral epithelial lesions, and also examined the relationship between EGFR gene aberration and the development of squamous cell carcinoma (SCC). Genomic DNA was extracted from paraffin sections of 17 cases of oral epithelial dysplasia (ED), four cases of carcinoma in situ (CIS), and 20 cases of untreated primary SCC. The extracted DNA was subjected to competitive PCR to amplify EGFR gene. Amplification of the EGFR gene was observed in three cases (17%) of ED, one case of CIS and four cases (20%) of SCC. In cases showing EGFR gene amplification, the degree of amplification was low in ED and CIS cases, whereas it was extremely high in SCC cases. These results suggest that amplification of EGFR gene occurs in the relatively early stage of the development of oral SCC. However, a high level of EGFR gene accumulation probably plays an important role in the progression to invasive cancer.

Identification of a stop codon mutation in the CBFA1 runt domain from a patient with cleidocranial dysplasia and cleft lip

We examined a patient with cleidocranial dysplasia (CCD) and cleft lip and found a new stop codon mutation in CBFA1. This mutation was a heterozygous C-to-T transition in exon 3 of CBFA1. This nucleotide change converts a CAA codon to a TAA (stop) codon at amino acid position Gln195 in the runt domain of CBFA1.