Lymph Glands Research Articles

Bovine Gammaherpesvirus 6 Tropism in the Natural Host

Bovine gammaherpesvirus 6 (BoHV-6) is endemic in cattle in Europe, with a high prevalence. There is evidence that the virus is a commensal and not associated with disease processes. For other gammaherpesviruses, it is known that they have a rather specific target cell spectrum, generally including B cells and, at least in the early phase of infection, the epithelium of the respiratory tract. In a previous study we detected BoHV-6 by quantitative PCR for the gB gene sequence of BoHV-6 in lung, bronchial lymph nodes, spleen and tongue with variable loads, suggesting cells in these tissues as target cells. In the present study, formalin-fixed, paraffin embedded samples of the same tissues from 10 cattle, with high overall BoHV-6 copy numbers, were examined by RNA in situ hybridization for BoHV-6 ORF73. This revealed extremely limited viral ORF73 transcription. A signal was only detected in individual lymphocytes within lymphatic follicles in bronchial lymph nodes, and within very rare alveolar epithelial cells and interstitial cells in the lungs, without any evidence of pathological changes in the tissues. No signal was detected in the spleen or in the oral mucosa of the tongue. The results are consistent with previous findings with other gammaherpesviruses, murine herpesvirus-68, ovine herpesvirus-2 and/or Epstein–Barr virus. They provide further evidence that BoHV-6 is without any consequence to the host and can indeed represent a commensal in cattle.

Tubercular dactylitis/Spina ventosa-A rare skeletal form of extrapulmonary tuberculosis.

A 9-year-old girl presented with progressive, painful swelling over the left index finger, associated with local signs of inflammation and restriction of finger movements. After the swelling was punctured using a needle, chronic discharging sinus formed. Examination revealed firm swelling over the right parotid area, bilateral cervical and left axillary lymphadenopathy, and firm swelling over the left index finger with a chronic discharging sinus over the lateral aspect of proximal phalanx. Mantoux intradermal injection was reactive (22x24 mm induration). Blood and pus cultures were sterile. Hand radiograph revealed dactylitis (Figure 1A-C). Fine aspiration and cytology of the cervical lymph node showed degenerated inflammatory cells, epithelioid granuloma and acid-fast bacilli. She was initiated on 4-drug antitubercular therapy (ATT). At 2-months follow-up, she was asymptomatic and had the pain and swelling over the left finger have reduced with significant radiological improvement. Tubercular dactylitis or 'spina ventosa' (wind-filled sail) refers to cystic expansion of short, tubular bones. It is commonly seen in younger children (between 1 and 6 years of age) and adults (between 20 and 50 years of age). A common presentation in endemic areas is presence of a painless, fusiform swelling over a single digit, most commonly the proximal phalanx of index or middle finger as in the index case, or over the metacarpals of middle and ring fingers. Earliest radiological clues include periosteitis followed by gradual destruction of bone and cyst formation in the cavity giving a ballooned-out appearance.

Dual role for Headcase in hemocyte progenitor fate determination in Drosophila melanogaster.

The hematopoietic organ of the Drosophila larva, the lymph gland, is a simplified representation of mammalian hematopoietic compartments, with the presence of hemocyte progenitors in the medullary zone (MZ), differentiated hemocytes in the cortical zone (CZ), and a hematopoietic niche called the posterior signaling centre (PSC) that orchestrates progenitor differentiation. Our previous work has demonstrated that the imaginal cell factor Headcase (Hdc, Heca) is required in the hematopoietic niche to control the differentiation of hemocyte progenitors. However, the downstream mechanisms of Hdc-mediated hematopoietic control remained unknown. Here we show that Hdc exerts this function by negatively regulating the insulin/mTOR signaling in the niche. When Hdc is depleted in the PSC, the overactivation of this pathway triggers reactive oxygen species (ROS) accumulation and, in turn, the differentiation of effector lamellocytes non-cell-autonomously. Although overactivation of insulin/mTOR signaling normally leads to an increase in the size of the hematopoietic niche, this effect is concealed by cell death caused by hdc loss-of-function. Moreover, we describe here that hdc silencing in progenitors causes cell-autonomous ROS elevation and JNK pathway activation, resulting in decreased MZ size and differentiation of lamellocytes. Similarly to the PSC niche, knocking down hdc in the MZ also leads to caspase activation. Notably, depleting Hdc in the progenitors triggers proliferation, an opposing effect to what is observed in the niche. These findings further our understanding of how progenitor maintenance in the larval lymph gland is controlled autonomously and non-cell-autonomously, and point towards new mechanisms potentially regulating HSC maintenance across vertebrates.

Diagnosis and management of Rosai–Dorfman disease of the breast: Case report and literature review

AbstractRosai–Dorfman disease (RDD) is a rare subtype of non–Langerhans cell histiocytosis. It is a benign disease with variable presentations, with breast involvement being an uncommon manifestation. In this paper, we present a case of breast RDD in a 59‐year‐old Chinese woman who presented with a painless, enlarging mass in her right breast, accompanied by skin changes and no palpable axillary lymph node. A mammogram and breast ultrasonography revealed a progressively enlarging lesion with a suspicious axillary lymph node, leading to an upgrade from Breast Imaging Reporting and Data System (BIRADS) score of 3 to 4A on interval imaging. Core biopsy of the breast mass and cytology of the right axillary lymph node confirmed extranodal RDD. After a 5‐year period of observation, excision was performed due to persistent symptoms. Local recurrence of RDD, with skin discolouration and thickening, was confirmed by skin biopsy 1 year and 9 months after the operation. To the best of our knowledge, this is the first reported case of breast RDD in Hong Kong.

6454 Identifying Gaps in Obtaining Germline RET Testing for Patients with Medullary Thyroid Cancer

Abstract Disclosure: A.N. Lim: None. J. Comeaux: None. C. Ricker: None. K.S. Wei: None. T.E. Angell: None. Background: Medullary thyroid carcinoma (MTC) occurs sporadically or from germline pathogenic variants of the RET proto-oncogene in multiple endocrine neoplasia type 2 (MEN2). Current ATA guidelines recommend germline RET testing in all patients with C-cell hyperplasia or MTC. Because disparities may exist in the implementation of this recommendation, we analyzed records of patients with MTC to identify variables associated with germline RET testing. Methods: Patients with MTC were identified from a cohort study of all adult patients undergoing thyroid surgery from 2015-2022 at two affiliated academic centers: a private hospital or a safety-net hospital. Patients were categorized as RET-tested or not RET-tested. Data collection included: patient age, gender, ethnicity, nodule and lymph nodule findings on ultrasound (US), calcitonin and CEA levels, and surgical pathology results. Medical reports were reviewed for reasons that RET testing was or was not obtained. Results: Of 24 MTC patients, 50% were female, mean age ± SD was 50.8 ± 12.3, and 15 (62.5%) had Hispanic ethnicity. RET testing was performed in 14 (58.3%) patients and 3 (21.4%) had a pathogenic variant. RET-tested patients had a median nodule size of 3.45 cm (IQR 2.40-4.53) vs. 2.40 cm (IQR 0.98-3.25) in not-RET tested patients (p<0.05). There were no significant differences between groups in age, gender, ethnicity, preoperative US findings, preoperative calcitonin or CEA levels, or histopathologic status. RET testing was performed in 11/14 (78.6%) patients at the private hospital vs. only 5/10 (50.0%) patients at the safety-net hospital (p=0.20). Considering this, we further investigated the use of RET testing in the initial management of MTC patients. RET testing was performed or planned during initial management in 13/14 (92.9%) patients at the private hospital vs. only 5/10 (50%) patients at the safety-net hospital (p=0.05). At the private hospital, RET testing was requested for apparent sporadic disease (n=11), family history of MTC (n=1), and coexistent pheochromocytoma (n=1). At the safety-net hospital, RET testing was requested for apparent sporadic disease (n=4) and family history of MTC (n=1), but reportedly was not pursued in 5 patients because MTC appeared to be sporadic. Discussion: In this cohort of patients with MTC, larger nodule size was significantly associated with the rate of germline RET testing. Larger MTC tumor size alone may have prompted greater attention to germline testing, but also may have been associated with other findings, which could be further assessed with a larger sample size by multivariable analysis. The disparity in RET testing as part of initial management at the safety-net hospital may be multifactorial, but future analyses should explore provider decision-making, as well as facility and patient variables. Presentation: 6/1/2024

7639 A Rare Cause of Lung Adenocarcinoma with Metastasis to the Thyroid

Abstract Disclosure: E. Echevarria-Torres: None. C.G. Yap: None. K.E. Izuora: None. A rare cause of lung adenocarcinoma with metastasis to the thyroid. Metastasis to the thyroid gland from non-thyroid malignancies is rare. When metastasis occurs, presenting symptoms are typically nonspecific, representing a diagnostic challenge. With the goal of raising awareness, we present a case of lung adenocarcinoma with metastasis to the thyroid. An 85-year-old man with a history of hypertension, hyperlipidemia and 60 years smoking history presented to the endocrine clinic for evaluation of subclinical hyperthyroidism. On the physical exam, there was fullness in the right thyroid area which on ultrasound showing a large right thyroid nodule occupying the entire lobe. There was also a solid 4.5 cm x 3.4 cm x 4.6 cm nodule in the mid-anterior left thyroid lobe. Fine needle aspiration cytology of right nodule revealed malignant cells and cell block material positive for TTF-1 (Thyroid Transcription Factor 1) concerning for malignancy. The left thyroid nodule cytology was consistent with benign follicular nodule. Chest CT ordered for surgical planning showed right upper lobe pleural-based lung opacity measuring 3.7 cm x 2.9 cm with supra clavicular lymphadenopathy. Biopsy of lung mass and supra clavicular lymph nodes revealed primary lung adenocarcinoma involving the lymph nodes consistent with stage Iva (cT3NxM1b). The patient was referred to oncology for further management. Discussion: Metastatic lesions to the thyroid gland account for less than 1 % of all malignant thyroid tumors with most cases found on autopsy. This is hypothesized to be due to the rich blood supply and high iodine content of the thyroid gland. Thyroid metastasis usually presents several years after initial diagnosis and treatment of non- thyroid malignancy. Patients can present with enlarging thyroid nodules, neck swelling, dysphagia and, in rare instances, upper airway obstruction. We present a rare case of lung cancer with metastasis into the thyroid. The thyroid nodule initially palpated upon physical exam led to eventual thyroid ultrasound and subsequently to his diagnosis of lung adenocarcinoma after findings of lung nodule which was biopsied and showed primary lung adenocarcinoma. TTF-1 was also positive which is typically expressed by lung adenocarcinomas. Treatment for thyroid metastasis is surgery, along with treatment of primary malignancy. The earlier the diagnosis and treatment the more favorable the prognosis. Radiotherapy and chemotherapy are other means to reduce the recurrence. Thyroid hormone replacement will be warranted post operatively for hypothyroidism. We present this uncommon case to raise awareness about the presentation of thyroid metastasis to enhance timely diagnosis and intervention. Presentation: 6/1/2024

Clarification of a unique mucosal vaccination route for improved systemic and mucosal immune response in broiler

There are often outbreaks of infectious diseases on farms, which not only disrupt production but also cause significant economic losses. Vaccines are given to prevent the spread of these infectious diseases, but they produce only systemic antibodies or antibodies in the mucosa of a particular system. So, a new mucosal vaccination route is needed where the vaccine will produce antibodies in the systemic circulation as well as in the mucosa of many systems. In our study, the cloaca was targeted because it is associated with the mucosa of many systems. Whole-mount and routine histological staining show both lymphatic nodules and diffuse lymphatic tissues in the lamina propria of cloaca. These lymphatic tissues are made up of Bu-1+ B-cells, CD3+ T-cells, and KUL01+ macrophages and monocytes. So, this is a new mucosa-associated lymphoid tissue, named cloaca-associated lymphoid tissue (CALT). The CALT contains antigen-presenting cells (dendritic cells, macrophages, B cells, MHC II molecules, and T cells) and is equipped with blood vessels and high endothelial venules, which indicate its functional status. More antibodies were produced in the treatment group compared to the vehicle control group after administration of the infectious bursal disease (IBD) and the Newcastle disease (ND) vaccine through cloaca. In addition, the cloaca-associated route produces a higher number of antibodies than the other traditional routes, which reveals the uniqueness of this route. Cloacal-vaccinated chickens showed less damage to the follicle and epithelium of the bursa of Fabricius compared to other groups, indicating its lower cytotoxic effect. Therefore, the cloaca-associated mucosal vaccination route produces more antibodies than other mucosal vaccination routes, which will protect the chickens on the farm to a greater extent.

The NF-κB Factor Relish maintains blood progenitor homeostasis in the developing Drosophila lymph gland.

Post-larval hematopoiesis in Drosophila largely depends upon the stockpile of progenitors present in the blood-forming organ/lymph gland of the larvae. During larval stages, the lymph gland progenitors gradually accumulate reactive oxygen species (ROS), which is essential to prime them for differentiation. Studies have shown that ROS triggers the activation of JNK (c-Jun Kinase), which upregulates fatty acid oxidation (FAO) to facilitate progenitor differentiation. Intriguingly, despite having ROS, the entire progenitor pool does not differentiate simultaneously in the late larval stages. Using expression analyses, genetic manipulation and pharmacological approaches, we found that the Drosophila NF-κB transcription factor Relish (Rel) shields the progenitor pool from the metabolic pathway that inducts them into the differentiation program by curtailing the activation of JNK. Although ROS serves as the metabolic signal for progenitor differentiation, the input from ROS is monitored by the developmental signal TAK1, which is regulated by Relish. This developmental circuit ensures that the stockpile of ROS-primed progenitors is not exhausted entirely. Our study sheds light on how, during development, integrating NF-κB-like factors with metabolic pathways seem crucial to regulating cell fate transition during development.

Adequacy Assessment in Lymph Node Aspirates: An Exploratory Cytomorphologic Analysis of Negative Cervical Node Aspirates of Head and Neck Carcinomas

Introduction: Fine-needle aspiration cytology (FNAC) of lymph node is sensitive for detection of metastatic carcinoma but not without a significant false-negative rate. This study reviews clinicocytological features of negative node aspirates to identify predictive factors for establishing adequacy criteria. Methods: Negative FNAC specimens matched with neck dissection from a primary diagnosis of head and neck squamous cell, or undifferentiated (nasopharyngeal) carcinoma were reviewed for clinical and cytological parameters including lymphoid, inflammatory, and background components. Results: Slides from 86 lymph node aspirates including 50 positive for metastasis on follow-up were retrieved. Higher total lymphocyte count, lymphoid fragment count, germinal center fragment count, undifferentiated histology, presence of histiocytes and absence of blood were associated with a true negative cytologic diagnosis (p < 0.05), but not node size or location (p > 0.05). Undifferentiated histology, small lymphoid and germinal center fragments were independent factors indicative of a true negative diagnosis (p < 0.05). Large lymphoid fragments (p = 0.052) demonstrated a trend. Assessment of lymphoid components over five hotspots high-power fields (HPFs) was more robust in predictive value than only one hotspot. Receiver operating characteristic curve identified >10 small lymphoid, >20 large lymphoid and >2 germinal center fragment per five HPFs as optimal adequacy thresholds. Stricter total lymphocyte count cutoff accompanies increase of diagnostic accuracy, up to 0.67 for ≥5 HPFs with >500 lymphocytes. Conclusion: Total counts of lymphoid and germinal center fragments from multiple HPFs are useful in adequacy assessment of lymph node aspirates and improve diagnostic performance of FNAC in exclusion of metastatic carcinoma.

Cholangiocarcinoma: Consistent clinical, cytological, hematological, and biochemical findings and pathomorphology of the liver and kidney in five exotic dog breeds in Abeokuta, Nigeria.

Cholangiocarcinomas are malignant neoplasms that originate from any part of the bile duct epithelium. It is one of the most common liver tumors in dogs. This study described the clinical, cytological, hematological, biochemical, and pathomorphological findings of five cholangiocarcinoma cases in exotic breed dogs aged 2-5 years to aid in clinical diagnosis. This study used dogs presented at different times from 2012 to 2021 at the Veterinary Teaching Hospital, Federal University of Agriculture, Abeokuta. History, clinical signs, and vital parameters were recorded. Blood samples were collected for hematology and serum chemistry. Abdominocentesis was performed for cytological diagnosis. All dogs died during treatment, and postmortem examinations were performed. At postmortem, fine needle aspirates were collected from the liver and mesenteric lymph nodes and liver and kidney samples were fixed in 10% neutral-buffered formalin. The dogs showed signs of severe malnutrition, jaundice, and bloating. The hematological analysis indicated anemia, neutrophilia without band neutrophils, and lymphopenia, indicative of a stress hemogram. The serum biochemistry test revealed lower levels of total proteins, albumin, and globulin and higher levels of serum enzymes. Abdominal fluid and mesenteric lymph node cytology revealed clusters of epithelial neoplastic cells. A postmortem examination revealed the liver's nodular enlargement with the presence of button-like ulcers. Neoplastic epithelial cells are solid masses with hyperchromatic nuclei surrounded by fibrous connective tissues. Cholangiocarcinoma, diagnosed over a period of time in five exotic breeds of dog, consistently presents with the same clinical and postmortem findings, aiding in clinical diagnosis. However, the diagnosis of the disease is not possible in the early stage because of the absence of specific clinical signs. In dogs and possibly other animal species presenting with emaciation, lethargy, icterus, and distended abdomen, cholangiocarcinoma should be suspected, and cytological examination of the abdominal fluid and lymph node aspirates should be performed despite the absence of advanced equipment.

REACTION OF LYMPHOID TISSUE IN THE WALL OF THE DUODENUM AND LYMPHOID PLAQUE IN RATS IN MODELING HYPOKINESIA

The damaging effect of hypokinesia on the functional state of lymphoid tissue in the wall of the duodenum and on the lymphoid plaque was established. It was found that the processes of cell destruction, suppression of the plasma reaction and blast transformation of cells are most pronounced in the wall of the duodenum. In the lymphoid plaque, along with a high level of destructive processes in lymphoid cells, lymphocytopoiesis is preserved in the centers of proliferation of lymphoid nodules and the proportion of plasma cells increases in the internodal zone, which indicates the development of compensatory processes under the long-term influence of hypokinesia.

Protein phosphatase 2A regulates blood cell proliferation and differentiation in Drosophila larval lymph glands.

Protein phosphatase 2A (PP2A), one of the most abundant protein phosphatases, has divergent functions in multiple types of cells. Its inactivation has been closely associated with leukemia diseases. However, the physiological function of PP2A for hematopoiesis has been poorly understood in organisms. Drosophila hematopoiesis parallels the vertebrate counterpart in developmental and functional features but involves a much simpler hematopoietic system. Here, utilizing the Drosophila major larval hematopoietic organ lymph gland, we studied the function of PP2A for hematopoiesis in vivo. By knocking down the expression of Pp2A-29B that encodes the scaffold subunit of the PP2A holoenzyme complex, we found that PP2A silencing in the differentiating hemocytes resulted in their excessive proliferation. Furthermore, this PP2A inhibition downregulated the expression of Smoothened (Smo), a crucial component in the Hedgehog pathway, and smo overexpression was able to rescue the phenotypes of PP2A depletion, indicating that Smo functions as a downstream effector of PP2A to restrict the hemocyte proliferation. PDGF/VEGF-receptor (Pvr) overexpression also restored the Smo expression and lymph gland morphology of PP2A silencing, suggesting a PP2A-Pvr-Smo axis to regulate lymph gland growth and hemocyte proliferation. Moreover, inhibiting PP2A activity in the blood progenitor cells promoted their differentiation, but which was independent with Smo. Together, our data suggested that PP2A plays a dual role in the Drosophila lymph gland by preserving the progenitor population and restraining the hemocyte proliferation, to properly regulate the hematopoietic process.

Two Decades of Thyroid Nodule Cytology in Children: Malignancy Risk Assessment at a Tertiary Care Center

Plain Language SummaryPediatric thyroid nodules are less common than those in adults, but they have a higher risk of being cancerous. This study reviews data from the past 20 years at a major healthcare center to understand how often these nodules are malignant in children and how accurate fine-needle aspiration (FNA) biopsies are in diagnosing them. The study analyzed 75 thyroid nodules from 73 children, finding that 62.6% of the nodules were malignant. The FNA biopsy, a key diagnostic tool, was shown to be very accurate, with a sensitivity of 78.38% and a perfect specificity of 100%. This means that FNA is highly reliable for identifying both cancerous and noncancerous nodules in children. One significant finding is that the risk of cancer in thyroid nodules categorized as indeterminate (uncertain) by the Bethesda System is much higher in children than in adults. This suggests that pediatric thyroid nodules behave more aggressively, underscoring the need for careful evaluation and tailored guidelines for children. These results are crucial for medical professionals as they highlight the importance of specialized approaches in managing thyroid nodules in children, ensuring accurate diagnosis and appropriate treatment to avoid overtreatment and unnecessary surgeries.

Intra-patient spatial comparison of non-metastatic and metastatic lymph nodes reveals the reduction of CD169+ macrophages by metastatic breast cancers

Breast cancer cells suppress the host immune system to efficiently invade the lymph nodes; however, the underlying mechanism remains incompletely understood. Here, we aimed to comprehensively characterise the effects of breast cancers on immune cells in the lymph nodes. We collected non-metastatic and metastatic lymph node samples from 6 patients with breast cancer with lymph node metastasis. We performed bulk transcriptomics, spatial transcriptomics, and imaging mass cytometry to analyse the obtained lymph nodes. Furthermore, we conducted histological analyses against a larger patient cohort (474 slices from 58 patients). The comparison between paired lymph nodes with and without metastasis from the same patients demonstrated that the number of CD169+ lymph node sinus macrophages, an initiator of anti-cancer immunity, was reduced in metastatic lymph nodes (36.7±21.1 vs 7.3±7.0cells/mm2, p=0.0087), whereas the numbers of other major immune cell types were unaltered. We also detected that the infiltration of CD169+ macrophages into metastasised cancer tissues differed by section location within tumours, suggesting that CD169+ macrophages were gradually decreased after anti-cancer reactions. Furthermore, CD169+ macrophage elimination was prevalent in major breast cancer subtypes and correlated with breast cancer staging (p=0.022). We concluded that lymph nodes with breast cancer metastases have fewer CD169+ macrophages, which may be detrimental to the activity of anti-cancer immunity. JSPS KAKENHI (16H06279, 20H03451, 20H04842, 22H04925, 19K16770, and 21K15530, 24K02236), JSPS Fellows (JP22KJ1822), AMED (JP21ck0106698), JST FOREST (JPMJFR2062), Caravel, Co., Ltd, Japan Foundation for Applied Enzymology, and Sumitomo Pharma Co., Ltd. under SKIPS.

Notch signaling promotes differentiation, cell death and autophagy in Drosophila hematopoietic system

Notch signaling is a highly conserved pathway between mammals and Drosophila and plays a key role in various biological processes. Drosophila has emerged as a powerful model for studying hematopoiesis and leukemia. In exception to crystal cells, the strength of Notch signaling in Drosophila lymph gland cortical zone (CZ)/intermediate zone (IZ) cells is weak. However, the influence of Notch activation in the lymph gland CZ/IZ cells and circulating hemocytes on hematopoietic homeostasis maintenance is unclear. Here, we showed that Notch activation in lymph gland CZ/IZ cells induced overdifferentiation of progenitors. Moreover, Notch activation promoted lamellocyte generation via NFκB/Toll signaling activation and increased reactive oxygen species (ROS). In addition, we found that Notch activation in lymph gland CZ/IZ cells and circulating hemocytes caused caspase-independent and nonautophagic cell death. However, crystal cell autophagy was activated by upregulation of the expression of the target gene of the Hippo/Yki pathway Diap1. Moreover, we showed that Notch activation could alleviate cytokine storms and improve the survival of Rasv12 leukemia model flies. Our study revealed the various mechanisms of hematopoietic dysregulation induced by Notch activation in healthy flies and the therapeutic effect of Notch activation on leukemia model flies.

Visual inspection versus spectrophotometry for xanthochromia detection in patients with sudden onset severe headache-A diagnostic accuracy study.

There is still disagreement about whether to routinely use spectrophotometry to detect xanthochromia in cerebrospinal fluid (CSF) or whether visual inspection is adequate. We aimed to evaluate the diagnostic accuracy of these methods in detecting an aneurysmal subarachnoid hemorrhage in patients with sudden onset severe headache. When a patient presents to the emergency department with a headache for which there is suspicion of a subarachnoid hemorrhage, the gold standard to rule this out is to perform a CSF analysis for xanthochromia with or without spectrophotometry if the cranial non-contrast computed tomography (CT) upon admission is negative. Having applied the gold standard, we retrospectively included patients with acute headache who underwent both CT scan and CSF spectrophotometry at our hospital in the period 2002-2020. Patients were excluded if the cranial CT was interpreted as positive, there was a bloody CSF, or if visual assessment data of the CSF was unavailable. We scrutinized the patients' medical records and evaluated the benefit of spectrophotometry compared to visual inspection. The net bilirubin absorbance cut-off for support of subarachnoid hemorrhage was set at >0.007 absorbance units. The spectrophotometry was also considered positive if the net bilirubin absorbance was ≤0.007 and net oxyhemoglobin absorbance was ≥0.1 absorbance units. We calculated and compared the sensitivity and specificity of CSF spectrophotometry and visual inspection of the CSF. In total, 769 patients, with a mean age of 42.3 ± (standard deviation [SD] = 17.3) years, were included. The headache onset was classified as a thunderclap headache in 41.5%, and 4.7% had a sudden loss of consciousness. Fifteen patients (2%) were finally diagnosed with a subarachnoid hemorrhage, six (0.8%) had an aneurysmal subarachnoid hemorrhage, seven (0.9%) had a perimesencephalic hemorrhage, one (0.1%) had a cortical cerebral sinus venous thrombosis, and one (0.1%) had a spinal epidural hematoma. Four patients (0.5%) had a subarachnoid hemorrhage that was not detected by visual inspection, and two were caused by an aneurysmal rupture. One of these two patients died just before intervention, and the other underwent coiling for an anterior communicating aneurysm. The number needed for lumbar puncture to detect a subarachnoid hemorrhage was 51, but 128 to detect an aneurysmal hemorrhage. The corresponding numbers needed for CSF spectrophotometric analysis were 192 and 385, respectively. Spectrophotometry was positive in 31 patients (4.0%), of whom 18 (2.3%) also had visually detected xanthochromia (11 true positive). The mean net bilirubin absorbance in the 13 samples with visually clear CSF was 0.0111 ± (SD = 0.0103) absorbance units, compared to 0.0017 ± (SD = 0.0013) in the CSF with negative spectrophotometry. The corresponding figures for net oxyhemoglobin absorbance were 0.0391 ± (SD = 0.0522) versus 0.0057 ± (SD = 0.0081). The sensitivity of spectrophotometric xanthochromia detection was 100% (95% confidence interval [CI], 78-100), compared to 73% (95% CI, 45-92) for visual xanthochromia detection. The specificity of spectrophotometric xanthochromia detection was 98% (95% CI, 97-99) compared to 99% (95% CI, 98-100) for visual xanthochromia detection. Both methods had high negative predictive values: 100% (95% CI, 99.5-100) versus 99.5% (95% CI, 98.6-99.9), respectively. Both visual inspection and spectrophotometry have high diagnostic accuracy for detecting CSF xanthochromia, but the lower sensitivity of visual assessment makes it unreliable, and we recommend the use of spectrophotometry in clinical practice.

Dual role of PpV in Drosophila crystal cell proliferation and survival.

Drosophila melanogaster crystal cells are a specialized type of blood cells for innate immune process upon injury. Under normal conditions, crystal cells rarely proliferate and constitute a small proportion of fly blood cells. Notch signaling has been known to guide the cell fate determination of crystal cells and maintain their survival. Here, we reported that protein phosphatase V (PpV), the unique catalytic subunit of protein phosphatase 6 in Drosophila, is a novel regulator of crystal cell proliferation and integrity. We found that PpV proteins highly accumulated in crystal cells in the larval hematopoietic organ termed the lymph gland. Silencing PpV using RNA interference led to increased crystal cell proliferation in a Notch-independent manner and induced crystal cell rupture dependent on Notch signaling. Moreover, additive PpV prevented the rupture of crystal cells in lymph glands upon a needle injury, suggesting the involvement of PpV in wound healing. Altogether, our results indicated that PpV plays a dual role in lymph glands, preventing crystal cell proliferation to limit the cell number, as well as inhibiting crystal cell rupture to maintain their survival.

Morphological and functional spleen development in crossbreed rabbits

The accelerated growth of muscle mass in productive broiler breeds is often associated with delayed organ development of integral body systems, particularly the immune structures. The spleen is the largest secondary immune organ in the mammalian body and is responsible for initiating immune responses to blood-borne antigens. It can only perform this function successfully if all of its tissue components are fully morphologically and functionally mature. The spleen was studied in meat production rabbits (early maturing crossbreed Hyplus) at 1, 10, 20, 30, 60 and 90 days of age. Morphological studies included anatomical dissection, clarification of topography, determination of mass parameters, preparation of smears and histological sections. Spleen histological sections were stained with haematoxylin and eosin, according to Van Gieson, and impregnated with silver nitrate, followed by microscopy. Qualitative and quantitative indicators of spleen cellular and tissue component development were determined using ImageJ software. It was found that in crossbred rabbits the topography of the spleen corresponds to general anatomical principles of localisation, has a fixed place and is an anatomically formed organ. In day-old animals, the histological differentiation of the spleen is limited to the connective tissue stroma and the parenchyma. The organ's parenchyma is formed by reticular tissue, with hematopoietic and lymphoid cells among the cells, without differentiation into white and red pulp. In 10-day-old rabbits, the white pulp is represented by the periarterial lymphatic sheath (PALS) and marginal zones. Single primary lymphoid nodules without germinal centres are seen in the spleen from 20 days of age. By 30 days of age, the white splenic pulp has all the major structural and functional zones, including formed lymphoid nodules with germinal centres and mantle zones. During the second and third months of life, the spleen gradually increases the relative area of all white pulp functional zones, reaching a maximum at 90 days of age. In productive rabbits, the cellular composition of the splenic white pulp is represented by lymphocytes (small, medium, large), reticular cells, macrophages and plasma cells. During postnatal ontogenesis, the number of small lymphocytes increases in all white pulp functional zones, reaching maximum values in 90-day-old animals. On the contrary, the relative number of medium and large lymphocytes decreases. The number of reticulocytes in the periarterial lymphatic sheath and lymphoid nodules zones does not change significantly, and in the marginal zone it decreases substantially by the end of the study. The results of determining the timing of morphological and functional maturation of immunocompetent structures in the spleen of meat rabbits are of great biomedical and economic importance. They will serve as a control for comparing changes in rabbit spleen lymphoid tissues during the development of pathological processes, as well as under the influence of external factors.

The Sentient Propagation-Reactive B Cell-Rich Lymphoid Proliferation

Reactive B cell-rich lymphoid proliferation is a heterogeneous group of non-neoplastic lymphoid cell proliferation recapitulating diverse B cell lymphomas. The lesion is commonly categorized as nodal and extra-nodal follicular proliferations, nodal and extra-nodal nodular proliferations or nodal and extra-nodal immunoblastic proliferations. Florid follicular hyperplasia is comprised of quantifiably enhanced, disseminated primary and secondary lymphoid follicles with irregular outlines. Hyperplastic Germinal Centres (GCs) are comprised of admixed centroblasts and centrocytes, reactive T cells, Follicular Dendritic Cells (FDCs) and tingible body macrophages. Lymph node architecture depicts lymphoid follicles comprised of cells expressing B cell antigens wherein primary follicles are pre-eminently constituted of small lymphocytes BCL2+, BCL6- and CD10- immune reactivity. Progressive Transformation of Germinal Centre (PTGC) is constituted of singular or few enlarged lymphoid follicles of 4x to 5x magnitude wherein mantle zone cells display extensive invagination into adjacent germinal centres. Hyaline Vascular Castleman’s Disease (HVCD) delineates innumerable lymphoid follicles confined to the lymph node cortex and medulla or diverse extramedullary sites.

Formation of the junctions between lymph follicles in the Peyer's patches even before postweaning activation

Peyer’s patches (PPs), which contain an abundance of B and T cells, play a key role in inducing pivotal immune responses in the intestinal tract. PPs are defined as aggregated lymph follicles, which consist of multiple lymph follicles (LFs) that may interact with each other in a synergistic manner. LFs are thought to be spherical in shape; however, the characteristics of their structure are not fully understood. To elucidate changes in the structure of PPs as individuals grow, we generated serial 2D sections from entire PPs harvested from mice at 2, 4, and 10 weeks of age and performed a 3D analysis using a software, Amira. Although the number of LFs in PPs was not changed throughout the experiment, the volume and surface area of LFs increased significantly, indicating that LFs in PPs develop continuously by recruiting immune cells, even after weaning. In response to the dramatic changes in the intestinal environment after weaning, the development of germinal centers (GCs) in LFs was observed at 4 and 10 weeks (but not 2 weeks) of age. In addition, GCs gradually began to form away from the center of LFs and close to the muscle layer where export lymphatic vessels develop. Importantly, each LF was joined to the adjacent LF; this feature was observed even in preweaning nonactivated PPs. These results suggest that PPs may have a unique organization and structure that enhance immune functions, allowing cells in LFs to have free access to adjacent LFs and egress smoothly from PPs to the periphery upon stimulation after weaning.