WHO 2022 classification of penile and scrotal cancers: updates and evolution.

Squamous cell carcinoma (SCC) is the most common malignant tumour of the penis. The 2022 WHO classification reinforces the 2016 classification and subclassifies precursor lesions and tumours into human papillomavirus (HPV)-associated and HPV-independent types. HPV-associated penile intraepithelial neoplasia (PeIN) is a precursor lesion of invasive HPV- associated SCC, whereas differentiated PeIN is a precursor lesion of HPV-independent SCC. Block-type positivity of p16 immunohistochemistry is the most practical daily utilised method to separate HPVassociated from HPVindependent penile SCC. If this is not feasible, the term SCC, not otherwise specified (NOS) is appropriate. Certain histologies that were previously classified as "subtypes" are now grouped, and coalesced as "patterns", under the rubric of usual type SCC and verrucous carcinoma (e.g. usual-type SCC includes pseudohyperplastic and acantholytic/pseudoglandular carcinoma, and carcinoma cuniculatum is included as a pattern of verrucous carcinoma). If there is an additional component of the usual type of invasive SCC (formerly termed hybrid histology), the tumour would be a mixed carcinoma (e.g. carcinoma cuniculatum or verrucous carcinoma with usual invasive SCC); in such cases, reporting of the relative percentages in mixed tumours may be useful. The consistent use of uniform nomenclature and reporting of percentages will inform the refinement of future reporting classification schemes and guidelines/recommendations. The classification of scrotal tumours is provided for the first time in the fifth edition of the WHO Blue book, and it follows the schema of penile cancer classification for both precursor lesions and the common SCC of the scrotum. Basal cell carcinoma of the scrotum may have a variable clinical course and finds a separate mention.

Dataset for the reporting of carcinoma of the bladder-cystectomy, cystoprostatectomy and diverticulectomy specimens: recommendations from the International Collaboration on Cancer Reporting (ICCR).

The International Collaboration on Cancer Reporting (ICCR) is a not for profit organisation whose goal is to produce standardised internationally agreed and evidence-based datasets for pathology reporting. With input from pathologists worldwide, the datasets are intended to be uniform and structured. They include all items necessary for an objective and accurate pathology report which enables clinicians to apply the best treatment for the patient. This dataset has had input from a multidisciplinary ICCR expert panel. The rationale for some items being required and others recommended is explained, based on the latest literature. The dataset incorporates data from the World Health Organization (WHO) 2016, and also from the latest (8th edition) TNM staging system of the American Joint Committee on Cancer (AJCC). Fifteen required elements and eight recommended items are described. This dataset provides all the details for a precise and valuable pathology report required for patient management and prognostication. This dataset is intended for worldwide use, and should facilitate the collection of standardised comparable data on bladder carcinoma at an international level.

Dataset for the reporting of urinary tract carcinoma-biopsy and transurethral resection specimen: recommendations from the International Collaboration on Cancer Reporting (ICCR).

The International Collaboration on Cancer Reporting (ICCR) is an alliance of major pathology organisations in Australasia, Canada, Europe, United Kingdom, and United States of America that develops internationally standardised, evidence-based datasets for the pathology reporting of cancer specimens. This dataset was developed by a multidisciplinary panel of international experts based on previously published ICCR guidelines for the production of cancer datasets. It is composed of Required (core) and Recommended (noncore) elements identified on the basis of literature review and expert consensus. The document also includes an explanatory commentary explaining the rationale behind the categorization of individual data items and provides guidance on how these should be collected and reported. The dataset includes nine required and six recommended elements for the reporting of cancers of the urinary tract in biopsy and transurethral resection (TUR) specimens. The required elements include specimen site, operative procedure, histological tumor type, subtype/variant of urothelial carcinoma, tumor grade, extent of invasion, status of muscularis propria, noninvasive carcinoma, and lymphovascular invasion (LVI). The recommended elements include clinical information, block identification key, extent of T1 disease, associated epithelial lesions, coexistent pathology, and ancillary studies. The dataset provides a structured template for globally harmonized collection of pathology data required for management of patients diagnosed with cancer of the urinary tract in biopsy and TUR specimens. It is expected that this will facilitate international collaboration, reduce duplication of effort in updating current national/institutional datasets, and be particularly useful for countries that have not developed their own datasets.

BTK gene targeting by homologous recombination using a helper-dependent adenovirus/adeno-associated virus hybrid vector.

X-linked agammaglobulinemia (XLA) is one of the most common humoral immunodeficiencies, which is caused by mutations in Bruton's tyrosine kinase (BTK) gene. To examine the possibility of using gene therapy for XLA, we constructed a helper-dependent adenovirus/adeno-associated virus BTK targeting vector (HD-Ad.AAV BTK vector) composed of a genomic sequence containing BTK exons 6-19 and a green fluorescence protein-hygromycin cassette driven by a cytomegalovirus promoter. We first used NALM-6, a human male pre-B acute lymphoblastic leukemia cell line, as a recipient to measure the efficiency of gene targeting by homologous recombination. We identified 10 clones with the homologous recombination of the BTK gene among 107 hygromycin-resistant stable clones isolated from two independent experiments. We next used cord blood CD34⁺ cells as the recipient cells for the gene targeting. We isolated colonies grown in medium containing cytokines and hygromycin. We found that the targeting of the BTK gene occurred in four of the 755 hygromycin-resistant colonies. Importantly, the gene targeting was also observed in CD19⁺ lymphoid progenitor cells that were differentiated from the homologous recombinant CD34⁺ cells during growth in selection media. Our study shows the potential for the BTK gene therapy using the HD-Ad.AAV BTK vector via homologous recombination in hematopoietic stem cells.

Collaboration of local governments and experts responding to the increase of the environmental radiation level secondary to the nuclear accident: a unique activity to relieve residents' anxiety.

After the Fukushima nuclear power plant accident, 'hot spots' were found in Tokatsu area in Chiba prefecture. Although ambient radiation dose in this area was too low to harm residents' health, local residents were particularly worried about possible adverse effects from exposure to radiation. To avoid unnecessary panic reactions in the public, local governments in Tokatsu area collaborated with radiation specialists and conducted activities to provide local residents with accurate information on health effects from radiation. In addition to these activities, the authors offered one-to-one consultations with a radiologist for parents of small children and expecting mothers. They herein report this unique attempt, focusing on parents' anxiety and the age of their children. Taken together, this unique collaborative activity between local government and experts would be one of the procedures to relieve residents' anxiety.

In vitro testing of zinc oxide sunscreens.

The UVA performances of two all-mineral zinc oxide sunscreens are measured following Colipa and ISO procedures and compared to a sunscreen containing only organic actives. It is found that the two sunscreen types yield very different in vitro SPF and UVA results. It shown that the results can be rationalized in terms of the differences in the monochromatic extinction spectra of the two types of sunscreens.

A phase II multi-center study of triple therapy with paclitaxel, S-1 and cisplatin in patients with advanced gastric cancer.

OBJECTIVES: To carry out a phase II multi-center study on the efficacy and safety of triple combination therapy with paclitaxel, S-1, and cisplatin in patients with unresectable/metastatic gastric cancer. METHODS: A total of 63 patients from 8 institutions were included in this study. Paclitaxel (160 mg/m²) was administered by infusion for 3 h on the first day. S-1 (70 mg/m²/day) was administered orally for 14 consecutive days from the first day. Cisplatin (60 mg/m²) was administered intravenously over 24 h on day 14 of every 28-day cycle. RESULTS: All 63 patients were assessed for clinical efficacy and safety. A total of 259 cycles of treatment were administered (median 4, range 1-10). Grade 3-4 toxicities included neutropenia in 30.2%, thrombocytopenia in 12.7%, and anemia in 11.1%. There was no grade 3-4 non-hematological toxicity or treatment-related death. Complete response was observed in 6 patients and partial response in 34 patients. The overall response rate was 63.5%. The median progression-free survival and response duration were 8.0 and 8.8 months, respectively, and median survival time was 15 months. CONCLUSIONS: Triple combination therapy with paclitaxel, S-1, and cisplatin showed promising safety and efficacy profiles with the potential to become a standard regimen for unresectable/metastatic gastric cancer.

Hyperocclusion stimulates osteoclastogenesis via CCL2 expression.

Excessive mechanical stress (MS) during hyperocclusion is known to result in disappearance of the alveolar hard line, enlargement of the periodontal ligament (PDL) space, and destruction of alveolar bone, leading to occlusal traumatism. We hypothesized that MS induces expression of osteoclastogenesis-associated chemokines in PDL tissue, resulting in chemotaxis and osteoclastogenesis during occlusal traumatism. We examined the effect of MS on relationships between chemokine expression and osteoclastogenesis using in vivo and in vitro hyperocclusion models. In an in vitro model, intermittent stretching-induced MS was shown to up-regulate the expression of CC chemokine ligand (CCL)2, CCL3, and CCL5 in PDL cells. The expression levels of CCL2 in PDL tissues, its receptor CCR2 in pre-osteoclasts, and tartrate-resistant acid-phosphatase-positive cells in alveolar bone were significantly up-regulated 4-7 days after excessive MS during hyperocclusion in in vivo rodent models. Hyperocclusion predominantly induced CCL2 expression in PDL tissues and promoted chemotaxis and osteoclastogenesis, leading to MS-dependent alveolar bone destruction during occlusal traumatism.

Comprehensive behavioural study of GluR4 knockout mice: implication in cognitive function.

Fast excitatory transmission in the mammalian central nervous system is mediated by AMPA-type glutamate receptors. The tetrameric AMPA receptor complexes are composed of four subunits, GluR1-4. The GluR4 subunit is highly expressed in the cerebellum and the early postnatal hippocampus and is thought to be involved in synaptic plasticity and the development of functional neural circuitry through the recruitment of other AMPA receptor subunits. Previously, we reported an association of the human GluR4 gene (GRIA4) with schizophrenia. To examine the role of the GluR4 subunit in the higher brain function, we generated GluR4 knockout mice and conducted electrophysiological and behavioural analyses. The mutant mice showed normal long-term potentiation (LTP) in the CA1 region of the hippocampus. The GluR4 knockout mice showed mildly improved spatial working memory in the T-maze test. Although the retention of spatial reference memory was intact in the mutant mice, the acquisition of spatial reference memory was impaired in the Barnes circular maze test. The GluR4 knockout mice showed impaired prepulse inhibition. These results suggest the involvement of the GluR4 subunit in cognitive function.

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma, nasal type.

BACKGROUND: Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms. PATIENTS AND METHODS: We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas. RESULTS: Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively. CONCLUSION: The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.

A novel protein, MAPO1, that functions in apoptosis triggered by O6-methylguanine mispair in DNA.

O(6)-Methylguanine produced in DNA induces mutation due to its ambiguous base-pairing properties during DNA replication. To suppress such an outcome, organisms possess a mechanism to eliminate cells carrying O(6)-methylguanine by inducing apoptosis that requires the function of mismatch repair proteins. To identify other factors involved in this apoptotic process, we performed retrovirus-mediated gene-trap mutagenesis and isolated a mutant that acquired resistance to a simple alkylating agent, N-methyl-N-nitrosourea (MNU). However, it was still sensitive to methyl methanesulfonate, 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, etoposide and ultraviolet irradiation. Moreover, the mutant exhibited an increased mutant frequency after exposure to MNU. The gene responsible was identified and designated Mapo1 (O(6)-methylguanine-induced apoptosis 1). When the expression of the gene was inhibited by small interfering RNA, MNU-induced apoptosis was significantly suppressed. In the Mapo1-defective mutant cells treated with MNU, the mitochondrial membrane depolarization and caspase-3 activation were severely suppressed, although phosphorylation of p53, CHK1 and histone H2AX was observed. The orthologs of the Mapo1 gene are present in various organisms from nematode to humans. Both mouse and human MAPO1 proteins expressed in cells localize in the cytoplasm. We therefore propose that MAPO1 may play a role in the signal-transduction pathway of apoptosis induced by O(6)-methylguanine-mispaired lesions.

Neuroendoscopically assisted cyst-cisternal shunting for a quadrigeminal arachnoid cyst causing typical trigeminal neuralgia.

A quadrigeminal cistern arachnoid cyst is a very rare cause of typical trigeminal neuralgia. A 62-year-old woman presented with right facial pain of 8 years duration. Neuroradiological findings revealed a cystic mass in the quadrigeminal region that compressed the cerebellum downward and the brainstem anteriorly and was associated with hydrocephalus. She had neuroendoscopically-assisted cyst-cisternal shunting via a small craniotomy. Postoperatively, the trigeminal neuralgia disappeared. The origin of the trigeminal neuralgia may have either been a marked distortion of the pons that caused stretching of the trigeminal nerve and irregular demyelination within the root entry zone, or there was contact between the root entry zone and a vascular structure. Neuroendoscopy is useful for treating arachnoid cysts; however, in order to safely relieve symptoms, the procedure needs to be appropriately adapted depending on the pathogenesis. In this paper, we review the literature and discuss the pathophysiology and treatment of our case.

EC-IC bypass using the distal stump of the superficial temporal artery as an additional collateral source of blood flow in patients with Moyamoya disease.

BACKGROUND: To establish multiple bypass flow in an adult Moyamoya disease patient, the distal stump of the parietal superficial temporal artery (dsPSTA) was used as an additional donor. METHODS: Its potential as the donor was first evaluated by measuring the arterial pressure directly in three patients, revealing about 80% in mean arterial pressure of those measured at the proximal stump and radial artery. The anastomosis was performed just as conventionally except an additional anastomosis between the dsPSTA and frontal branch of the middle cerebral artery in 10 hemispheres of 7 patients. RESULTS: The patency of the dsPSTA bypass was confirmed on postoperative angiography in 5 patients. The comparison of pre- and post-operative single photon emission computed tomography was feasible in 8 hemispheres of 6 patients of which 7 demonstrated improvement of the cerebral blood flow. CONCLUSION; This technique provides a novel source of donor artery in the treatment of Moyamoya disease, in which multiple anastomoses are desirable.

Prevention of radiation-induced pneumonitis by recombinant adenovirus-mediated transferring of soluble TGF-beta type II receptor gene.

To investigate whether radiation-induced pneumonitis in the mouse-irradiated lung could be prevented by recombinant adenovirus-mediated soluble transforming growth factor-beta (TGF-beta) type II receptor gene therapy. Radiation fibrosis-prone mice (C57BL/6J) were randomly divided into four groups consisting of a (1) control group (sham-irradiated); (2) radiation (RT)-alone group; (3) RT+AdCMVsTbetaR group and (4) RT+AdCMVluc group. The RT-alone and sham-irradiated mice were killed at several time points after thoracic irradiation with a single dose of 9 Gy, and then the TGF-beta1 concentrations in serum and broncho-alveolar lavage fluid (BALF) were quantified by enzyme-linked immunosorbent assay (ELISA). We used an adenoviral vector expressing a soluble TGF-beta type II receptor (AdCMVsTbetaR), which can bind to TGF-beta and then block the TGF-beta receptor-mediated signal transduction. The C57BL/6J mice were intraperitoneally (i.p.) injected with either 5 x 10(8) plaque-forming units of AdCMVsTbetaR or AdCMVluc, a control adenovirus-expressing luciferase, a week preceding and a week following the X-ray thoracic irradiation. Four weeks after irradiation, the mice were killed and the concentration of TGF-beta1 in the serum and BALF were then measured using ELISA and the lung tissue specimens were examined histopathologically. Following thoracic irradiation with a single dose of 9 Gy, radiation-induced TGF-beta1 release in the serum reached the first peak concentration at 12 h and then declined. It reached a maximal value at 2 weeks after irradiation. In the BALF, the TGF-beta1 concentration was appreciable within the first hour and thereafter declined. It reached a maximal value at 3 days after irradiation. A one-time i.p. injection of AdCMVsTbetaR 1 week before irradiation could not completely suppress the two peaks of the radiation-induced TGF-beta1 increase, whereas an injection a week preceding and a week following thoracic irradiation was able to suppress those two peaks thoroughly. The TGF-beta1 was completely suppressed in the AdCMVsTbetaR-treated mouse serum and BALF; however, no statistical difference was observed in the serum and BALF between the AdCMVluc-infected mice and the control mice at 4 weeks after irradiation (P < 0.05). A histopathological examination showed only mild radiation pneumonitis in the irradiated lungs of AdCMVsTbetaR-treated mice in comparison to the AdCMVluc-infected and RT-alone mice. Our results demonstrated that TGF-beta1 plays an important role in radiation pneumonitis, thus suggesting that the adenovirus-mediated overexpression in soluble TGF-beta type II receptor gene therapy may be a potentially feasible and effective strategy for the prevention of radiation pneumonitis.

Hematopoietic stem cell transplantation for natural killer-cell lineage neoplasms.

Neoplasms of natural killer (NK)-lineage are rare. Their prognosis is generally poor except for cases of solitary nasal NK-cell lymphoma. The NK-cell Tumor Study Group performed a survey in Japan on patients diagnosed between 1994 and 1998. Of 228 patients selected for analysis, 40 underwent HSCT (15 allografts and 25 autografts). The underlying diseases were myeloid/NK cell precursor acute leukemia (n = 4), blastic NK-cell lymphoma (n = 11), aggressive NK-cell leukemia (n = 3), and nasal-type extranodal NK-cell lymphoma (n = 22). At the time of HSCT, 22 patients were in complete remission (CR), 11 were in relapse, and seven were primary refractory. All patients received myeloablative conditioning regimens including total-body irradiation. Sixteen died of disease progression, and six of treatment-related causes. Overall, 4-year survival was 39% with a median follow-up of 50 months; this was significantly better than that of patients who did not undergo HSCT (21%, P = 0.0003). For patients transplanted in CR, the 4-year overall survival was 68%, which was significantly better than that of patients who went into CR but did not undergo HSCT (P = 0.03). These findings suggest that the HSCT is a promising treatment strategy for NK-cell lineage.

Usefulness of epithelial membrane antigen (EMA) to discriminate between perineural invasion and perineural indentation in prostatic carcinoma.

AIMS: Perineural invasion (PNI) is one of the few unequivocal criteria to diagnose adenocarcinoma of the prostate. Distinguishing PNI from perineural indentation (PNIn), however, is sometimes difficult. The aim of this study was to discriminate between PNI and PNIn using EMA immunohistochemistry. METHODS AND RESULTS: We selected representative sections from 87 prostatectomies with prostatic adenocarcinoma. Normal peripheral nerves were continuously encircled with perineurium, which was immunoreactive for EMA. We identified 1319 PNI by carcinomas, 368 PNIn by carcinomas, and 303 PNIn by benign glands. We categorized the EMA immunoreactivity patterns into three classes: samples that displayed discontinuity or complete loss of the perineurium (Type A), samples where there were carcinomas or benign glands in the perineural space or peripheral nerves (Type B) and samples that showed no changes in the perineurium (Type C). For PNI we observed Type A, Type B, and Type C patterns in 55.3%, 24.8% and 19.9% of carcinomas, respectively. The incidence of each of those patterns in PNIn by carcinomas was 32.1%, 14.9% and 53.0%, respectively. Cases of PNIn by benign glands showed Type A or Type C patterns. They did not, however, exhibit Type B patterns. CONCLUSION: EMA immunostaining will aid the diagnosis of prostatic adenocarcinoma.

A phase II multicentric trial of S-1 combined with 24 h-infusion of cisplatin in patients with advanced gastric cancer.

BACKGROUND: The aim of this multicentric trial was to determine the clinical toxicities and antitumor effects of a chemotherapy regimen of S-1 combined with cisplatin in patients with inoperable locally or metastatic advanced gastric cancer. PATIENTS AND METHODS: Forty-two patients were entered into the study. S-1 (80 mg/m2) was administered orally daily for 14 consecutive days and 24-h infusion of cisplatin (70 mg/m2) was administered on day 8 of every 28-day cycle. RESULTS: The overall response rate was 50% and complete response rate was 5%. The most common adverse event was leucopenia, which occurred with grade 3 in 7 patients (16.6%) and grade 4 in 2 patients (4.8%). Non-hematological adverse events were generally mild. The median survival time was 342 days. The 2-year survival rate was 22.9%. CONCLUSION: This combination chemotherapy is active, convenient and well tolerated in patients with high-grade advanced gastric cancer.

Endoscope assisted removal of jugular foramen schwannoma; report of 3 cases.

Removal of the intraforaminal portion of a jugular foramen schwannoma under direct vision requires resection of the adjacent bone. Extensive resection of the bone around the jugular foramen, however, involves a potential danger for cerebrospinal fluid (CSF) leakage and for damage to the adjacent cranial nerves as well as venous outflow. To avoid such bone resection, we applied the endoscope during the removal of a jugular foramen schwannoma through the lateral suboccipital approach. Three patients with schwannomas in the jugular foramen were treated using the lateral suboccipital approach with endoscopic assistance. After the intracranial portion was first removed under the microscope, the residual tumor in the jugular foramen was subsequently removed under the side-viewing endoscope. In all cases the tumor was removed successfully without major complications. The authors conclude that if the cases are selected properly, removal of the schwannoma extending into the jugular foramen is feasible through the conventional lateral suboccipital window under endoscopic assistance.

DNA typing for Helicobacter pylori isolates from eradication-failed patients: comparison of the isolates before and after therapy.

BACKGROUND: Failure of Helicobacter pylori eradication occurs frequently despite use of multiple microbial agents. AIM: We aimed to study differences between H. pylori strains isolated before and after eradication failure. METHODS: We treated 87 patients with peptic ulcer using triple therapy consisting of omeprazole plus combinations of clarithromycin, amoxicillin, or metronidazole. We studied the status of cagA, vacA, and iceA by PCR, and examined the differences in H. pylori isolates by pulsed-field gel electrophoresis and arbitrary primer polymerase chain reaction. The minimum inhibitory concentration of clarithromycin, amoxicillin, or metronidazole was determined by an agar dilution method. RESULTS: Eradication therapy failed in 12 patients (14%); H. pylori isolates were obtained from all of these both before and after therapy. After eradication therapy, 10 patients were colonized with the same strain as before therapy, while the other two patients were colonized with different strains from those before therapy. In the former group, one isolate changed from metronidazole-sensitive to -resistant, one changed from clarithromycin- and metronidazole-sensitive to -resistant, and four were resistant to clarithromycin or metronidazole both before and after therapy. The other four isolates remained sensitive to clarithromycin and metronidazole after therapy. In the two patients who yielded apparently different isolates after therapy, they changed from clarithromycin- and metronidazole-sensitive to -resistant. CONCLUSION: Eradication of H. pylori by first-line therapy is an important goal in the treatment of H. pylori-positive peptic ulcer, and that appropriate antimicrobial sensitivity testing should be conducted in patients with eradication failure.

[Idiopathic hemothorax associated with shock during transporting in an ambulance; report of a case].

A 37-year-old man was admitted to our hospital. The patient noted sudden right back pain after coughing before 1 hour. Loss of consciousness was occurred in an ambulance. Chest X-P revealed whole fluid in the right chest. Enhanced chest computed tomography (CT) revealed extravasation of contrast media into the pleural cavity from the right chest wall. Thoracentesis was performed to relieve dyspnea and 2,000 ml of blood was removed. Then hemoglobin count was dropped to 3.8 g/dl. At thoracotomy whole blood was sucked about 3,900 ml. Bleeding point was found at third intercostal vein. The vein was knotted and sutured by prolene thread. The bleeding lesion was no inflammation and no string like tissue. We report a case of idiopathic hemothorax and enhanced chest CT was useful for diagnosis of bleeding lesion of pleural cavity.