Three-dimensional reconstructed images after rotational angiography in the evaluation of intracranial aneurysms: surgical correlation.

OBJECTIVE: To evaluate the diagnostic accuracy of three-dimensional reconstructed images from rotational digital subtraction angiography in the surgical treatment of intracranial aneurysms. METHODS: Twenty-two patients with 34 intracranial aneurysms underwent biplane angiography (40 degrees per s, 4.5 degrees per image, 8.8 frames per s). Three-dimensional (3-D) reconstructed images were obtained at a separate Advantage 3.1 workstation (General Electric, Milwaukee, WI) after the rotational images were transferred. The available visualization techniques included maximum intensity projection, shaded surface display, and virtual endoluminal view. All images were evaluated in correlation with intrasurgical visual data recorded on digital videotapes. RESULTS: 3-D reconstructed images correlated well with surgical findings. The shape of the aneurysms, their neck size, and their relationships to the parent vessels and other branches were depicted clearly, especially compared with images obtained by two-dimensional conventional digital subtraction angiography and magnetic resonance angiography. CONCLUSION: 3-D digital subtraction angiography enables the surgeon to understand the 3-D structure of lesions and is very useful in planning the surgical treatment of cerebral aneurysms.

[Surgery for acoustic neurinoma treated by gamma-knife radiosurgery: a case report].

A 52-year-old woman had a history of left hearing loss for 5 years. An acoustic neurinoma with 3.2 cm in diameter was diagnosed and treated with gamma-knife radiosurgery (19 Gy of marginal dose) 1 year and 4 months ago. She developed headache, nausea, and visual disturbance 1 month prior to admission. Slight left facial palsy appeared after radiosurgery. Magnetic resonance imaging demonstrated the tumor with central necrosis in the left cerebellopontine angle cistern, increasing in size to 3.5 cm in diameter, and hydrocephalus. Tumor removal was performed incompletely, because of the fibrous appearance of the tumor and severe adherence with the surrounding cerebellar tissue. Facial palsy did not worsen after surgery. Since the hydrocephalus was not resolved, a right ventriculo-peritoneal shunt was inserted. The clinical course in this case suggests that tumor removal followed by radiosurgery was an approximately effective treatment for large acoustic neurinoma.

Progenies of fetal thymocytes are the major source of CD4-CD8+ alpha alpha intestinal intraepithelial lymphocytes early in ontogeny.

Present literature supports the view of an extrathymic origin for the subset of intestinal intraepithelial lymphocytes (IEL) that express the CD4-CD8+ alpha alpha phenotype. This subset would include virtually all T cell receptor (TCR) gamma delta IEL and a portion of TCR alpha beta IEL. However, these reports do not exclude the possibility that some CD4-CD8+ alpha alpha IEL are actually thymically derived. To clarify this issue, we examined the IEL day 3 neonatally thymectomized (NTX) mice. NTX resulted in as much as 80% reduction in total TCR gamma delta IEL and in a nearly complete elimination of TCR alpha beta CD4-CD8+ alpha alpha IEL early in ontogeny (3- to 5-week-old mice). The thymus dependency of TCR gamma delta IEL and TCR alpha beta CD4-CD8+ IEL was less prominent in older mice (7- to 10-week-old mice), as the total number of these IEL increased in NTX mice, but still remained severalfold less than that in euthymic mice. Furthermore, we demonstrate, by grafting the fetal thymus of CBF1 (H-2b/d) mice under the kidney capsule of congenitally nude athymic mice of BALB/c background (H-2d), that a substantial number of TCR gamma delta IEL and TCR alpha beta CD4-CD8+ alpha alpha IEL can be thymically derived (H-2b+). In contrast, but consistent with our NTX data, grafting of adult thymi into nude mice generated virtually no TCR gamma delta IEL and relatively less TCR alpha beta CD4-CD8+ alpha alpha IEL than did the grafting of fetal thymi. These results suggest that the thymus is the major source of TCR gamma delta and TCR alpha beta CD4-CD8+ alpha alpha IEL early in ontogeny, but that the extrathymic pathway is probably the major source of these IEL later in ontogeny. A reassessment of the theory that most CD4-CD8 IEL are extrathymically derived is needed.

Extrathymic and thymic origin of murine IEL: are most IEL in euthymic mice derived from the thymus?

Although an abundance of literature supports the hypothesis that murine intestinal intraepithelial lymphocytes (IEL) can develop extrathymically, whether most IEL in euthymic mice ar extrathymically derived is unknown. Recent evidence, however, suggests that the development of most IEL in euthymic mice is influenced either directly or indirectly by the thymus. While some evidence suggests that the thymus can influence the extrathymic development of IEL through time-derived factors, clearly a substantial portion (if not most) of the IEL in euthymic mice are derived directly from the thymus. The ability of the thymus to generate IEL depends on the age of the thymus, as fetal/neonatal thymus up to approximately 2 weeks of age generates a totally different subset of IEL than the adult thymus. These results suggest that the IEL generated from the fetal early neonatal thymus recognize a different antigen than the IEL generated from the adult thymus. The former probably recognizes self-antigen and the later recognizes bacterial antigen.

Thymus-derived cytokine(s) including interleukin-7 induce increase of T cell receptor alpha/beta+ CD4-CD8- T cells which are extrathymically differentiated in athymic nude mice.

Extrathymic T cell differentiation pathways have been reported, although the thymus is the main site of T cell differentiation. The thymus is also known to produce several cytokines that induce proliferation of thymocytes. In the present study, we investigated the influence of thymus-derived cytokines on extrathymic T cell differentiation by intraperitoneal implantation with a diffusion chamber which encloses fetal thymus (we named it fetal thymus-enclosed diffusion chamber, FTEDC) in athymic BALB/c nu/nu mice. Increase in number of T cells bearing T cell receptor (TcR) alpha/beta was detected in lymph nodes and spleens of FTEDC-implanted nude mice 1 week after implantation, whereas no such increase was detected in control nude mice implanted with a diffusion chamber without thymus. The FTEDC-induced increase of T cells was suppressed by intraperitoneal injection of anti-interleukin-7 monoclonal antibody (mAb). The TcR alpha/beta T cells in FTEDC-implanted BALB/c nu/nu mice preferentially expressed V beta 11, although V beta 11-positive T cells are deleted in the thymus of euthymic BALB/c mice by clonal elimination of self-super-antigen Dvb11-specific T cells. TcR alpha/beta T cells in FTEDC-implanted nude mice were of CD4-CD8- phenotype and showed no proliferative response against anti-TcR monoclonal antibody stimulation. These results suggest that the thymus can induce extrathymic T cell differentiation through the influence of thymus-derived cytokine(s) including interleukin-7, and that such extrathymically differentiated T cells have acquired only a little or no ability for proliferation when they recognize antigen by their TcR.

Thymus influences the development of extrathymically derived intestinal intraepithelial lymphocytes.

Overwhelming evidence suggests that the majority of murine small intestinal intraepithelial lymphocytes (IEL) are extrathymically derived. These IEL include those with T cell receptor (TCR) gamma delta and some TCR alpha beta (CD8 alpha alpha and Thy-1-). In contrast, congenitally athymic nude mice have low numbers of gamma delta TCR IEL as well as very few alpha beta TCR IEL, far less than that would be expected if one assumes that gamma delta TCR IEL and alpha beta TCR (CD8 alpha alpha and Thy-1-) IEL in euthymic mice are extrathymically derived. To examine this discrepancy, we followed extrathymic IEL differentiation in IEL of day 3-thymectomized (NTX) mice as another athymic mouse model and found that gamma delta TCR IEL and extrathymically derived alpha beta TCR IEL in NTX mice are markedly reduced, almost to the level of nude mice. We further show that it is probably the absence of a thymic stroma that is responsible for the lower amounts of extrathymically derived IEL in nude mice, as the low amounts can be corrected to euthymic levels by syngeneic fetal thymus grafting but not by direct injection of F1 thymocytes. Lastly, unlike TCR/CD3+ extrathymically derived IEL, we noted a large proportion of extrathymic CD3-CD8- and CD3-CD8+ IEL; they were threefold more frequent in nude and NTX than in euthymic mice. This suggests that the thymus influences extrathymically derived IEL in its development from CD3- to CD3+ at the small intestinal epithelium.

Precursor cells to CD3-intermediate (CD3int) liver mononuclear cells in the adult liver: further evidence for the extrathymic development of CD3int liver mononuclear cells.

Liver mononuclear cells (LMNC) can be divided into CD3-high positive (CD3hi), CD3-intermediate positive (CD3int) and CD3- populations. CD3int LMNC, but not CD3hi LMNC, are considered to be extrathymically derived because they are found in the liver of nude mice and adult thymectomized lethally irradiated bone marrow chimeras. CD3int LMNC express NK1.1 and show a skewed T cell receptor (TCR) V region repertoire with relatively high levels of V beta 8 and V alpha 14 expression, further suggesting that they belong to a different lineage from conventional T cells, which lack NK1.1 expression and V region skewing. Since the liver has been proposed to be a site of extrathymic T cell differentiation in adult mice, we analyzed LMNC for the presence of T cell precursors. CD3- LMNC contained CD4- CD8- cells and CD4lo CD8- cells. Reverse transcription-polymerase chain reaction analysis showed both CD3- populations express the recombination-activating gene -1, which is indispensable in gene rearrangement of TCR and expressed by thymic T cell precursors. Furthermore, when electronically sorted CD3- LMNC were cultured in medium without any feeder cells or exogenously added cytokines for 24 h, CD3int cells, but not CD3hi cells, appeared. These results suggest that the adult liver contains T cell precursors that lack the expression of the CD3/TCR complex, but are strongly committed to differentiate into extrathymic liver CD3int T cells.

Extrathymic development of self-reactive gamma(delta) T cells in athymic BALB/c nu/nu mice.

In the present report, we demonstrated that extrathymic gamma(delta) T cells proliferated in the mixed culture of lymph node cells of BALB/c nu/nu mice and irradiated syngeneic spleen cells (syngeneic MLR). Reverse transcription-polymerase chain reaction (RT-PCR) analyses revealed that V(delta)5 and V(delta)6 were dominantly expressed by the gamma(delta) T cells from the syngeneic MLR. Furthermore, the syngeneic MLR may expand V(delta)5+ T cells with BALB invariant delta (BID) sequence which is specifically detected in BALB background mice because V(delta)5 RT-PCR products from syngeneic MLR were digested with an AluI restriction enzyme which cut the D(delta)2-J(delta)1 junction of the BID sequence but not those of most non-BID V(delta)5 sequences. Interestingly, anti-mycobacterial and mammalian heat shock protein (Hsp) 60 mAb ML30 suppressed the generation of V(delta)5 with an AluI site in syngeneic MLR. These results suggest that extrathymically derived V(delta)5+ and V(delta)6+ gamma(delta) T cells recognize BALB/c self antigens and that the Hsp60 or an Hsp60-related molecule may be involved in the anti-self response of V(delta)5+ BID+ gamma(delta) T cells.

CD3-CD8+ intestinal intraepithelial lymphocytes (IEL) and the extrathymic development of IEL.

Present evidence suggests that a majority of murine CD3+ intraepithelial intestinal lymphocytes (IEL) are extrathymically derived T cells and that these extrathymically derived IEL phenotypically express the CD8 homodimer (CD8 alpha alpha). Recently, CD3- IEL have been reported to express the recombination activating gene (RAG-1), suggesting that precursors to extrathymically derived CD3+CD8+ alpha alpha IEL exist on the intestinal epithelium. To study in detail whether these CD3-IEL can develop into CD3+CD8+ alpha alpha IEL, we analyzed the CD3-IEL subset and found that it can be separated into two subsets, namely CD3-CD8- and CD3-CD8+ IEL. We show that (1) CD3-CD8- IEL are mostly small, non-granular and phenotypically Pgp-1+ IL-2R+ B220-, while CD3-CD8+ IEL are mostly large, granular and phenotypically Pgp-1- IL-2R+ B220+, (2) CD(3-)-CD8+ IEL express the RAG-1 gene, and (3) CD3-CD8-, CD3-CD8+ and CD3+CD8+ alpha alpha IEL, respectively, appear sequentially in normal ontogeny and in bone marrow-reconstituted thymectomized radiation chimeras. In the latter, virtually all CD3+CD8+ alpha alpha IEL expressed the gamma delta T cell receptor (TCR), but not the alpha beta TCR. From this and what is presently known about T cell development, we propose that CD3-CD8+ IEL are an intermediate in extrathymic IEL development and that the development of extrathymically derived IEL occurs at the intestinal epithelium from CD3-CD8- to CD3-CD8+ to CD3+(gamma delta TCR)CD8+ alpha alpha.

Appearance of extrathymic early differentiated CD4-CD8- T cells with T cell receptor gamma/delta or alpha/beta after thymus grafting to nude mice: influence of thymus on extrathymic T cell differentiation.

Fetal thymus grafting into athymic nude mice has been used as an experimental model of T cell development. To understand the early events of T cell development, we have examined the sequence of appearance of T cell subsets in lymph nodes (LN) of BALB/c nu/nu mice after grafting with syngeneic fetal thymus. T cells expressing T cell receptor (TCR) alpha/beta or gamma/delta increased in LN from 1 week after grafting, although no host-derived CD3+ T cells were detected in the grafted thymus and no donor thymus-derived T cells were detected in the LN. The early appearing T cells of both TCR alpha/beta and TCR gamma/delta showed a CD4-CD8- phenotype. V region usage analysis of the early appearing TCR alpha/beta T cells revealed that they contained cells bearing V beta 3 or V beta 11, which are potentially reactive to self-superantigen Mls-2a or Dvb11, respectively, and are deleted in the course of T cell development in the thymus of euthymic BALB/c mice. The early appearing T cells showed neither mixed lymphocyte reaction nor cytotoxic T cell activity against allogeneic cells. In contrast, lymphokine-activated killer cells from early appearing T cells, which contained high percentages of TCR gamma/delta T cells, exhibited higher cytotoxic activity against P815 mastocytoma than those from euthymic mice or untreated nude mice. All these results suggest that the early appearing T cells are developed extrathymically. We propose that the thymus may induce extrathymic T cell development without direct cell-to-cell interaction. It seems likely that the extrathymically developed T cells, especially TCR gamma/delta T cells, induced by the thymus have some role in the defense mechanism in the absence of conventional thymus-derived T cells.

Thymus ontogeny and the development of TCR alpha beta intestinal intraepithelial lymphocytes.

Murine T cell receptor (TCR) alpha beta intestinal intraepithelial lymphocytes (IEL), which express the CD8 molecule as a homodimer (CD8 alpha alpha), can be divided into two subsets: those which are CD4+ (CD4+CD8+alpha alpha) and those which are CD4- (CD4-CD8+alpha alpha). Here, we demonstrate that most TCR alpha beta CD4+CD8+alpha alpha IEL and TCR alpha beta CD4-CD8+alpha alpha IEL subsets appear to be of thymus origin, as neonatal thymectomy of BALB/c mice on Day 3 nearly eliminated both subsets. To further support this hypothesis, we demonstrate by grafting the thymus of CBF1 (BALB/c x C57BL/6) mice into nude mice that the thymus is capable of generating both TCR alpha beta CD4-CD8+alpha alpha IEL and TCR alpha beta CD4+CD8+alpha alpha IEL. However, which of the two TCR alpha beta IEL subsets is generated depends largely on the age of the thymus. The thymus from fetal up to 2 weeks of age generates predominantly TCR alpha beta CD4-CD8+alpha alpha IEL, but very scant amounts CD4+CD8+alpha alpha IEL. In contrast, the thymus after 2 weeks of age generates very little TCR alpha beta CD4-CD8+alpha alpha IEL, but generates an abundant amount of TCR alpha beta CD4+CD8+alpha alpha IEL. These results are consistent with the observation in euthymic mice that TCR alpha beta CD4-CD8+alpha alpha IEL precede the appearance of TCR alpha beta CD4+CD8+alpha alpha IEL by several weeks, thus further suggesting that the thymus is the major source of both TCR alpha beta IEL subsets.

Characteristics of fetal thymus-derived T cell receptor gamma delta intestinal intraepithelial lymphocytes.

We have previously demonstrated that grafting of CBF1 (H-2b/d) fetal thymus (FTG) under the kidney capsule of congenitally athymic nude mice of BALB/c background (H-2d) generates a substantial number of T cell receptor (TCR) gamma delta intestinal intraepithelial lymphocytes (IEL) that were of FTG origin (H-2b+) (see accompanying report). Here we investigated the characteristics of these FTG-derived TCR gamma delta IEL and compared them to the extrathymically derived TCR gamma delta IEL found in nude mice. Phenotypically, FTG-derived TCR gamma delta IEL were similar to their extrathymically derived counterparts in that most were Thy-1-, CD5- and CD8 alpha alpha (homodimer). V gamma and V delta gene usage in thymus-derived and extrathymically derived TCR gamma delta IEL were found to be virtually the same. Functionally, FTG-derived TCR gamma delta IEL were similar to the TCR gamma delta IEL found in euthymic mice as both were relatively anergic to TCR cross-linking in vitro. However, FTG-derived TCR gamma delta IEL differed slightly from extrathymically derived TCR gamma delta IEL, which were completely nonresponsive to the same in vitro stimulation. Overall, these findings support the view that FTG-derived and extrathymically derived TCR gamma delta IEL are almost indistinguishable. Lastly, we demonstrate that despite their thymic origin, development of FTG-derived TCR gamma delta IEL partially takes place extrathymically; that is positive selection of FTG-derived V delta 4 IEL occurs extrathymically. In addition, we demonstrate that the CD8 molecule is not necessary for development and homing of FTG-derived TCR gamma delta IEL. This later finding suggests that the CD8 alpha alpha molecule develops extrathymically for FTG-derived CD8 alpha alpha TCR gamma delta IEL.