Gaps and fragmentation of the superficial cortex in the abdominal and pelvic lymph nodes of elderly Japanese

Gaps and fragmentation of the superficial lymph node cortex are considered to provide intranodal shunt flow between the afferent and efferent vessels. Using serial sections of 205 nodes obtained from 27 donated cadavers more than 70 years of age, we examined the histological architecture of the abdominal and pelvic nodes in elderly Japanese. Secondary follicles were rare in the specimens. Cortex gaps were, to a greater or lesser degree, found in all nodes. We classified these nodes into three types according to how often the gap occurred. Type 1 nodes, with a relatively complete shield for the afferent lymph, were most frequently found in gastric nodes, whereas type 3 nodes, with numerous gaps, were often observed in the colic, para-aortic and pelvic nodes. The type 3 nodes showed a specific architecture characterized by a fragmented superficial cortex, three-dimensionally assembled cords and a common sinus between them. Primary follicles were located in the assembled cord structures as well as at the superficial cortex. Irrespective of the type, B and T lymphocyte areas were intermingled in the cortex-like areas. The present results reveal region-specific histological heterogeneity in aged human visceral nodes. Due to increased surface areas, the type 3 architecture seemed to accelerate systemic immunity rather than act as a local barrier in the para-aortic and pelvic nodes, which are located centrally along the lymphatic drainage routes. However, thick trabeculae often seemed to develop in the type 3 sinus to decrease nodal function with aging.     

System for inducible expression of cre-recombinase from the Foxa2 locus in endoderm, notochord, and floor plate.

We targeted the reverse tetracycline controlled transactivator (rtTA) to the Foxa2 locus (Foxa2(ITA)) to generate a system for regulating Cre-recombinase activity within Foxa2 expression domains, including the endoderm, notochord, and floor plate of early mouse embryos. The use of an internal ribosomal entry site to obtain rtTA expression preserves Foxa2 function of the targeted allele. Cre activity with this system reflects the level of endogenous Foxa2 activity and is also tightly controlled by doxycycline. The location of Cre activity within the broader Foxa2 expression domain can be restricted by altering the timing of doxycycline administration. Isolated floor plate expression can be obtained in this manner. This system will provide a useful tool for manipulating gene expression in endoderm, notochord, and floor plate, all of which are tissues with important structural and patterning functions during embryogenesis.     

Spontaneous coronary artery dissection mimicking aortic dissection

A 51-year-old woman suffered rapidly irreversible cardiogenic shock with left hemiparesis. Transesophageal echocardiography, which represents an essential imaging tool in the emergency room, ruled out aortic dissection involving branch vessels but did not allow an in vivo diagnosis of spontaneous coronary dissection. The in vivo diagnosis of spontaneous coronary dissection is rather difficult because of the dramatic clinical presentation and selective coronary angiography requirement.     

Non-redundancy of cytidine deaminases in class switch recombination

Class switch recombination (CSR), somatic hypermutation, and gene conversion are immunoglobulin diversification mechanisms that are strictly dependent on the activity of the activation-induced cytidine deaminase (AID). The precise role and substrate(s) of AID in these processes remain to be well defined. The closest homologue of AID is APOBEC-1, a bona fide mRNA-editing enzyme, which shares with AID the ability to deaminate cytidines within single-stranded DNA in vitro and in prokaryotic cells. To determine whether APOBEC-1 can therefore substitute for AID in activated B cells, we expressed human AID, a catalytic mutant thereof, and rat APOBEC-1 in AID-deficient murine B cells. Whereas AID rescued CSR, neither the inactive mutant nor APOBEC-1 could complement AID deficiency. This indicates that cytidine deaminase activity is necessary but not sufficient to initiate CSR, and suggests that AID is specifically targeted to its cognate substrate, the immunoglobulin genes or a distinct mRNA, by an as-yet-unknown mechanism.     

How many lymph nodes are necessary to stage early and advanced adenocarcinoma of the sigmoid colon and upper rectum?

The lymph-node yields in specimens resected for colorectal adenocarcinoma show considerable variations, raising the question whether the minimum lymph-node number recommended by the UICC (International Union Against Cancer) for pN0 classification represents an appropriate quality standard for specimen work-up. The number of pericolic lymph nodes recovered from 568 archival surgical colorectal carcinoma specimens located in the sigmoid or upper rectum showed a highly statistically significant correlation with both the pT category and the presence of metastases (P<0.0005). The median lymph-node yield in standardized (i.e., resembling in size surgically removed cancer specimens) tumor-free specimens obtained during autopsies was 13 lymph nodes, compared with 20.5 when diverticula were present and more than 30 in specimens with chronic inflammation or from patients with systemic infections. In 48 pT2 and pT3 carcinoma specimens prospectively dissected in the same way, median numbers of 18 (pT2) and 23 (pT3) lymph nodes were detected (range between 8 and 39 nodes). The lymph-node numbers recommended in previous studies and by the UICC often seem to be too low to declare a specimen free of metastases. Although the great variation in lymph-node counts requires the recovery of all lymph nodes for pN0 classification, recommendations considering the pT status and additional factors like diverticula and inflammatory changes can be useful as a quality standard for specimen work up.     

结核性淋巴结炎的“结节病”样变型

对１２例经病理学专家会诊、从病变上认定的淋巴结“结节病”石蜡包埋组织，应用结核杆菌ＤＮＡ特异性序列片段的聚合酶链反应（Ｍ．ＴＢ－ＰＣＲ）技术、ＢＣＧ免疫组化（ＢＣＧ－ＩＨＣ）技术和抗酸染色（ＡＦ）进行了分支杆菌／结核杆菌检测。在这１２例考虑为“结节病”的病例中：有１例呈ＢＣＧ－ＩＨＣ和Ｍ。ＴＢ－ＰＣＲ两项阳性；另１例呈ＡＦ、ＢＣＧ－ＩＨＣ和Ｍ．ＴＢ－ＰＣＲ三项阳性。研究结果提示：（１）某些结核性淋巴结炎可呈结节病样病变；（２）淋巴结结节病很可能与分支杆菌／结核杆菌感染有关。     

The proliferative capacities of popliteal lymph node lymphocytes and of their functionally distinct T-cell subpopulations from young-adult and old mice

Young adult and old mice were immunized by footpad injection of dinitrophenyl-conjugated bovine gamma-globulin (DNP-BGG) in complete Freund's adjuvant. A comparison of lymph node weight and total number of nucleated cells per lymph node as a function of time after antigen injection demonstrated a significantly greater absolute increase in lymph node weight and peak number of nucleated cells per lymph node in young-adult than in old animals. However, as judged by this increase in total nucleated cells, other than being delayed in old mice, the magnitude of these in situ proliferative responses appeared comparable for young-adult and old mice. That is, the antigen-stimulated to non-stimulated cell ratio did not differ significantly between young-adult and old animals. This was because lymph nodes from old animals prior to antigen injection always weighed less and had fewer numbers of nucleated cells compared with young-adult animals. Therefore, the in vitro cellular proliferative response of three T-cell-enriched lymphocyte subpopulations from young-adult and old mice was further characterized. This was done by measuring [3H]thymidine incorporation following antigen- (DNP-BGG)- or mitogen-[phytohemagglutinin (PHA) or Concanavalin A (Con A)]-induced proliferation and assessing their quantitative and/or qualitative requirements for macrophages. In contrast to the markedly reduced proliferation of the two T-cell subpopulations from popliteal lymph nodes which respond to PHA and Con A in old animals primed 21-days earlier with DNP-BGG, antigen-induced in vitro cellular proliferation of the small T-cell subset in old mice specifically responsive to the immunizing antigen DNP-BGG always responded as well as, if not better than, cells from young-adult mice.     

神经移位治疗火器性肌皮神经和腋神经损伤

在观察和测量100个上肢解剖标本的基础上,我们设计了带血管的胸背神经和下肩胛下神经移位,一期修复一例火器性肌皮神经和腋神经损伤.术后8个月复查功能恢复甚为满意.