The proximal regulatory element of the interferon-gamma promoter mediates selective expression in T cells

Interferon-gamma (IFN-gamma) is produced by natural killer cells and certain subsets of T cells, but the basis for its selective expression is unknown. Within the region between -108 and -40 base pairs of the IFN-gamma promoter are two conserved and essential regulatory elements, which confer activation-specific expression in T cells. This report describes studies indicating that the most proximal of these two regulatory elements is an important determinant of its restricted expression. The proximal element is a composite site that binds members of the CREB/ATF, AP-1, and octamer families of transcription factors. Jun is essential for activation-induced transcription and binds preferably as a heterodimer with ATF-2. In contrast, CREB appears to dampen transcription from this element. The CpG dinucleotide in this element is selectively methylated in Th2 T cells and other cells that do not express IFN-gamma, and methylation markedly reduces transcription factor binding. As a target for DNA methylation and for binding of transcription factors that mediate or impede transcription, this element appears to play a central role in controlling IFN-gamma expression.

Renal response to blood pressure elevation in normal and glomerulonephritic rats

Concurrent renal disease appears to augment greatly the adverse effects of systemic hypertension on renal function and the development of glomerulosclerosis. This study examined the effects of systemic hypertension and treatment of hypertension in groups of normal non-nephritic rats and rats submitted to 16 wk of glomerulonephritis induced by the administration of anti-glomerular basement membrane antibody. Hypertension was produced by application of a clip to the right renal artery and blood pressure was treated with an angiotensin-converting enzyme (ACE) inhibitor, quinapril. Glomerulosclerosis of two types developed: a diffuse type that is characteristic of anti-glomerular basement membrane glomerulonephritis, and a focal segmental glomerulosclerosis that is characteristic of systemic hypertension. Glomerulonephritis significantly reduced the capacity of ACE inhibitors to decrease systolic blood pressure in awake animals. In addition, glomerulonephritis produced significant effects on plasma angiotensin II concentrations, whereby ACE inhibition no longer lowered plasma angiotensin II levels and in fact produced an increase. Glomerular capillary hydrostatic pressure and hydrostatic pressure gradient correlated with systolic blood pressure and with the incidence of focal glomerulosclerosis in non-nephritic rats. However, in glomerulonephritis, systolic blood pressure no longer correlated with glomerular capillary pressure, and glomerular capillary pressure no longer correlated with the development of glomerulosclerosis, although systolic blood pressure did correlate with the degree of focal segmental glomerulosclerosis. Concurrent glomerulonephritis strongly conditions the effects of superimposed hypertension by altering the relationship between systemic blood pressure and glomerular capillary hydrostatic pressure and by decreasing the response of hypertension to therapy.

Metered-dose inhaler technique and quality of life with airways disease: assessing the value of the Vitalograph in educational intervention

The efficacy of delivering medicines by metered-dose inhaler (MDI) is well established, and the patient's technique with MDIs is related directly to achieving the desired clinical outcome. The present study was designed to assess and improve MDI technique by using a Vitalograph Aerosol Inhalation Monitor (VAIM) in an airways disease education programme. Baseline measurements were made immediately prior to educational intervention incorporating feedback from a VAIM unit. At 6 weeks' follow-up, MDI technique was found to have regressed to the sub-optimal measures recorded at baseline prior to educational intervention. However, patients reported a significant improvement in physical function between baseline and follow-up as measured by the Rand 36-Item Health Survey (SF-36), Version 1.0. The results reinforce the need for a longitudinal educational programme for patients prescribed medications delivered by MDI. The VAIM unit provided health educators and patients with both a visual and a quantitative assessment of patients' MDI technique, and was thus of positive value as part of the intervention process.

The role of angiogenic factor bFGF in the development of dural AVFs

PURPOSE

Dural arteriovenous fistulas (dAVFs) are known to be acquired disorders. Angiogenic stimulants, such as basic fibroblast growth factor (bFGF), may be involved in the evolution of this disorder. We examined the appearance and localization of bFGF, in human dAVF sinuses, versus a control using immunohistochemical techniques, to evaluate these qualitative differences.

PATIENTS AND METHODS

Four human dural sinuses from dAVF patients, and one control dural sinus were removed at surgery or autopsy and used for this study. Immunohistochemistry for bFGF was performed in all five specimens to identify its appearance and localization. Immunohistochemistry for alpha smooth muscle actin, factor VII related antigen, and macrophage (CD-68) were done in all tissues to identify the bFGF positive cell types.

RESULTS

In the control dural sinus, there was negative staining by bFGF immunohistochemistry. However, in all four sinuses of the dAVF patients, smooth muscle cells, endothelial cells, and meningeal cells were stained positively in various degrees by bFGF immunohistochemistry.

CONCLUSION

bFGF may be significant in the development of dAVFs, judging from its strong immunoreactivity in the sinuses of dAVF patients.

Transsphenoidal pituitary resection for preoperative diagnosis of prolactin-secreting pituitary adenoma in women: long term follow-up

The long term efficacy and safety of transsphenoidal resection for preoperative diagnosis of PRL-secreting pituitary adenomas in a large series of women have not been described. Four hundred and nine consecutive women at this university tertiary referral center undergoing transsphenoidal resection for preoperative diagnosis of PRL-secreting pituitary adenoma were followed for a minimum of 4 yr. The objective was to determine the efficacy and morbidity of this procedure and to identify features correlating with the resolution of hyperprolactinemia. Outcome measures included referral, preoperative, surgical, postoperative hospitalization, and long-term follow-up information, including recent PRL concentration. Follow-up was ascertained in 83% of patients who were followed for a mean of 9.2 yr. Recurrence of hyperprolactinemia occurred in 47% of total patients, but in only 16% with a single surgical procedure, histological diagnosis of prolactinoma, and postoperative PRL concentration of 5 ng/mL or less. The best single predictor of cure was postoperative day 1 PRL concentration of 5 ng/mL or less. Eighty-eight percent of women desiring conception conceived within 1 yr. Glucocorticoid-dependent hypopituitarism occurred in 23% of patients undergoing postoperative radiotherapy. There was no operative mortality. Operative morbidity was low. Our experience demonstrates that women undergoing transsphenoidal surgery for diagnosis of PRL-secreting adenoma form a heterogeneous patient population. The best long term results are achieved in the pure prolactinoma group, for whom transsphenoidal resection is generally safe and effective.

Extracellular matrix and integrin composition of the normal bladder wall

We performed an immunohistochemistry study of the normal human bladder so as to understand the interactions of extracellular matrix (ECM) components and the integrins of cell adhesion that accommodate the volume changes and maintain an impermeable barrier to reabsorption of urine in the bladder. The normal human urothelial cell and/or its plasma membrane contained integrins alpha 3, alpha V, beta 1, and beta 4 but did not contain integrin beta 3. The urothelial basement membrane (UBM) contained collagen type IV and laminin. Fibronectin and integrins alpha 3 and beta 4 were found in or near the UBM area, with types I and III collagen and tenascin abutting the area. The patterns of collagen, laminin, tenascin, vitronectin, fobronectin, and the alpha 3, alpha V, beta 1, and beta 3 integrins in the lamina propria, vessels, nerves, and smooth-muscle layers are described. These findings detail the normal anatomical ECM/integrin relationship that provides the cellular basis for bladder-wall relationships responsible for its impermeable state and other functions.

Cloning of rat 92-kDa type IV collagenase and expression of an active recombinant catalytic domain

A full-length cDNA for rat 92-kDa type IV collagenase was isolated and sequenced. RNase protection assay revealed tissue specific differential expression of the 92-kDa type IV collagenase in the rat during development. Natural and modified forms of the 92-kDa type IV collagenase were expressed. One active protein, 92-CD, contained only the putative catalytic domain. Large quantities of the 92-CD were expressed in Escherichia coli, extracted from inclusion bodies, purified, and refolded to an active form. This recombinant protein was able to cleave denatured and native collagen and was inactivated by known MMP inhibitors.

Radiation response and survival time in patients with glioblastoma multiforme

The determine the value of radiographically assessed response to radiation therapy as a predictor of survival in patients with glioblastoma multiforme (GBM), the authors studied a cohort of 301 patients who were initially treated according to uniform clinical protocols. All patients had newly diagnosed supratentorial GBM and underwent the maximum safe resection followed by external- beam radiation treatment (60 Gy in standard daily fractions or 70.4 Gy in twice-daily fractions of 160 cGy). The radiation response and survival rates were assessable in 222 patients. The extent of resection and the immediate response to radiation therapy were highly correlated with survival, both in a univariate analysis and after correction for age and Karnofsky performance scale (KPS) score in a multivariate Cox model (p< 0.001 for radiation response and p=0.04 for extent of resection). A subgroup analysis suggested that neuroimaging obtained within 3 days after surgery served as a better baseline for assessment of radiation response than images obtained later. Imaging obtained within 3 days after completion of a course of radiation therapy also provided valid radiation response scores. The impact of the radiographically assessed radiation response on survival time was comparable to that of age or KPS score. This information is easily obtained early in the course of the disease, may be of value for individual patients, and may also have implications for the design and analysis of trials of adjuvant therapy for GBM, including volume-dependent therapies such as radiosurgery or brachytherapy.

Bromodeoxyuridine labeling index in glioblastoma multiforme: relation to radiation response, age, and survival

PURPOSE

Various measures of the rate of tumor cell proliferation have been found to predict survival in patients with intracerebral gliomas. We correlated the bromodeoxyuridine labeling index (BrdUrd LI) with the response to radiation therapy, survival, and known prognostic factors in a series of patients with glioblastoma multiforme (GM) to test its utility as a prognostic factor.

METHODS AND MATERIALS

The BrdUrd LI was determined in 200 newly diagnosed intracranial GMs. Age and sex were known for all patients. The response to radiation therapy was determined in 116 patients by comparing neuroimaging studies obtained before and after external beam radiation therapy. Survival was analyzed in 64 patients who were treated according to two consecutive prospective clinical protocols.

RESULTS

The median BrdUrd LI was 6.5% (mean, 7.2%; range, 1.1-25.4%). The BrdUrd LI did not correlate significantly with age, sex, radiation response, or survival. Age and Karnofsky performance score were independent prognostic factors in our cohort.

CONCLUSION

The proliferative rate as measured by BrdUrd LI was not a prognostic factor in our GM cohort. The BrdUrd LI did not correlate significantly with known prognostic factors in GM. There was no significant relationship between BrdUrd LI and radiation response.

Venous angiography is needed to interpret inferior petrosal sinus and cavernous sinus sampling data for lateralizing adrenocorticotropin-secreting adenomas

Bilateral simultaneous venous sampling of ACTH from the inferior petrosal sinus is a reliable test for diagnosing Cushing's disease, but is not reliable for lateralizing ACTH-secreting pituitary adenomas. We reviewed 23 consecutive patients with Cushing's disease who underwent venous angiography of the cavernous and inferior petrosal sinuses followed by bilateral simultaneous venous sampling of ACTH in the inferior petrosal and cavernous sinuses. Venous drainage was bilaterally symmetric in 14 patients (61%) and asymmetric in 9 (39%). The most common asymmetric pattern (6 patients) was for blood from both cavernous sinuses to drain into the right inferior petrosal sinus, with no significant drainage into the left. Cavernous sinus sampling in 21 patients correctly lateralized the tumor in 12 cases of symmetric venous drainage, but in only 3 cases of asymmetric drainage. Inferior petrosal sinus sampling in all 23 patients correctly lateralized the tumor in 12 cases of symmetric drainage, but in only four cases of asymmetric drainage. Overall, venous sampling correctly lateralized 70% of the tumors. Incorrect lateralization in cases of asymmetric venous drainage is probably attributable to shunting of blood toward the side of dominant venous drainage. Our findings illustrate the need for venography in all patients undergoing venous sampling of ACTH because an understanding of the venous drainage patterns is essential to correctly interpret venous sampling data and warn physicians that the lateralization data may be incorrect or unreliable.

Intervention of CD4+ cell subset shifts and autoimmunity in the BXSB mouse by murine CTLA4Ig

In the BXSB autoimmune disease-prone mouse strain, male mice develop severe lupus-like symptoms and die early in life (4-6 mo), whereas females do not. We have previously demonstrated that profound phenotypic and functional changes occur with age in CD4+ cells from BXSB males. CD4+ cells from males (4 mo old) were predominantly CD44high, CD45RBlow, and MEL-14low (activated/memory phenotypes), while the reciprocal phenotypes characteristic of naive cells were prevalent in age-matched females and young adult males (2 mo old). CD4+ cells from older males proliferated less and produced less IL-2 and IFN-gamma than cells from either females or young males in response to immobilized anti-CD3 mAb. We tested the effect of CTLA4Ig treatment on the progression of disease in BXSB males. CD4+ cells from CTLA4Ig-treated mice at 4 mo of age were predominantly CD44low, CD45RBhigh, and MEL-14high phenotypes that were identical with those observed in CD4+ cells from young (3-mo-old) females. In contrast, control male mice treated with IgG2a accumulated the CD4+ memory phenotype. CD4+ cells from 4-mo-old male CTLA4Ig-treated mice proliferated and produced IL-2 at levels similar to those of cells from females in response to immobilized anti-CD3 mAb. Furthermore, in contrast to IgG2a-treated mice, female and CTLA4Ig-treated male mice at 4 mo of age produced no anti-chromatin Abs. Three of four male mice injected with CTLA4Ig until 6 mo of age appeared healthy at 8 mo of age, whereas all five of IgG2a-treated control males died by 6 mo of age. These 8-mo-old CTLA4Ig-treated males showed variable resistance to autoimmunity as well as function and phenotype marker expression, and a less striking glomerulonephritis than 4-mo-old untreated males. The results of this study demonstrate that the rampant T cell activation and T cell dysfunction that occur in male BXSB mice by 4 mo of age are abrogated by blocking the CTLA4-dependent costimulatory signal(s). They also show that treatment with CTLA4Ig can suppress the pathogenesis of disease and increase longevity.

Intervention of CD4+ cell subset shifts and autoimmunity in the BXSB mouse by murine CTLA4Ig

In the BXSB autoimmune disease-prone mouse strain, male mice develop severe lupus-like symptoms and die early in life (4-6 mo), whereas females do not. We have previously demonstrated that profound phenotypic and functional changes occur with age in CD4+ cells from BXSB males. CD4+ cells from males (4 mo old) were predominantly CD44high, CD45RBlow, and MEL-14low (activated/memory phenotypes), while the reciprocal phenotypes characteristic of naive cells were prevalent in age-matched females and young adult males (2 mo old). CD4+ cells from older males proliferated less and produced less IL-2 and IFN-gamma than cells from either females or young males in response to immobilized anti-CD3 mAb. We tested the effect of CTLA4Ig treatment on the progression of disease in BXSB males. CD4+ cells from CTLA4Ig-treated mice at 4 mo of age were predominantly CD44low, CD45RBhigh, and MEL-14high phenotypes that were identical with those observed in CD4+ cells from young (3-mo-old) females. In contrast, control male mice treated with IgG2a accumulated the CD4+ memory phenotype. CD4+ cells from 4-mo-old male CTLA4Ig-treated mice proliferated and produced IL-2 at levels similar to those of cells from females in response to immobilized anti-CD3 mAb. Furthermore, in contrast to IgG2a-treated mice, female and CTLA4Ig-treated male mice at 4 mo of age produced no anti-chromatin Abs. Three of four male mice injected with CTLA4Ig until 6 mo of age appeared healthy at 8 mo of age, whereas all five of IgG2a-treated control males died by 6 mo of age. These 8-mo-old CTLA4Ig-treated males showed variable resistance to autoimmunity as well as function and phenotype marker expression, and a less striking glomerulonephritis than 4-mo-old untreated males. The results of this study demonstrate that the rampant T cell activation and T cell dysfunction that occur in male BXSB mice by 4 mo of age are abrogated by blocking the CTLA4-dependent costimulatory signal(s). They also show that treatment with CTLA4Ig can suppress the pathogenesis of disease and increase longevity.

Evidence for a second function of the MA sequence in the Rous sarcoma virus Gag protein

During retrovirus assembly, Gag proteins bind to the inner leaflet of the plasma membrane to initiate the budding process. The molecular basis of this protein-lipid interaction is poorly understood. For the human, immunodeficiency virus type 1 Gag protein, we recently reported that the membrane-binding domain resides within the N-terminal 31 amino acids and consists of two components: myristate and a cluster of basic residues, which together promote membrane binding in vitro and budding in vivo (W. Zhou, L. J. Parent, J. W. Wills, and M. D. Resh, J. Virol. 68:2556-2569, 1994). The positively charged residues associate electrostatically with acidic phospholipids to stabilize membrane binding, while myristate provides membrane-binding energy via hydrophobic interactions. Here we demonstrate that the human immunodeficiency virus type 1 Gag membrane-binding domain can fully replace the membrane-targeting function of the N-terminal 100 residues of the non-myristylated Rous sarcoma virus (RSV) Gag protein. To further explore the importance of myristate and basic residues in membrane binding, we developed a gain-of-function assay whereby budding was restored to defective mutants of RSV Gag. Detailed mutational analysis revealed that the position, number, and context of charged residues are crucial to budding. Myristate provides additional membrane-binding energy, which is critical when a Gag protein is near the threshold of stable membrane association. Finally, viruses with altered matrix (MA) proteins that are noninfectious, even though they produce particles with high efficiency, were identified. Thus, we present the first evidence that the RSV MA sequence plays two distinct roles, membrane binding during particle assembly and a second, as yet undefined function required for viral infectivity.

Slow-flow vascular malformations of the pons: capillary telangiectasias?

PURPOSE

To report clinical and MR features that suggest telangiectatic vascular malformations of the pons:

METHODS

The MR scans and clinical data of 12 patients demonstrating an enhancing pontine lesion with minimal or no signal abnormality on T2-weighted images were reviewed. None of the patients underwent angiography or biopsy. Follow-up scans, available for all patients between 3 weeks and 40 months (range, 11.5 months), were reviewed.

RESULTS

The patients presented with a variety of symptoms including headache (n = 4), vertigo (n = 3), gait abnormality (n = 3), and hearing loss (n = 2). Two were referred for biopsy or treatment of presumed pontine glioma. On precontrast MR, 3 of 12 lesions were isointense on both T1- and T2-weighted images. Three of 12 lesions were slightly hypointense on T1-weighted images and 8 of 12 were slightly hyperintense on T2-weighted images. Postgadolinium images showed a discrete focus of enhancement with irregular or brushlike borders. Eight of 12 had an anomalous draining vessel from the lesion to the surface of the pons. None demonstrated mass effect or hemorrhage. Gradient-echo sequences in 7 patients all showed marked T2 shortening, despite the absence of hemorrhage on either T1- or T2-weighted images. None of the follow-up scans showed radiographic or clinical progression.

CONCLUSION

The benign clinical course, lack of mass effect, and minimal or no T2 prolongation argue against neoplasm and instead indicate a vascular cause. We suspect the decreased signal on gradient-echo sequences represents elevated intravascular deoxyhemoglobin from stagnant blood flow. The findings are atypical for cavernous angioma or classic venous malformation. Although pathologic confirmation is lacking, the radiographic features are most consistent with capillary telangiectasia or a transitional capillary-venous malformation. Despite the absence of progression or hemorrhage in any of the patients to date, the long-term prognosis currently is unknown. We emphasize the importance of recognizing the nonneoplastic nature of these lesions.

Interstitial pneumonitis as a late complication of high dose therapy with cyclophosphamide/thiotepa and peripheral blood progenitor cell rescue for carcinoma of the breast

The incurability of metastatic breast cancer with conventional chemotherapy has prompted many units to investigate the role of high dose chemotherapy and autologous stem cell rescue in patients with advanced or poor risk primary disease. Although preliminary data from centres treating patients with these modalities are encouraging, both in terms of rapidity of haemopoietic recovery and progression free survival, there is nonetheless a procedure related toxicity. We describe a patient with inflammatory carcinoma of the breast who received high dose cyclophosphamide and thiotepa prior to peripheral blood progenitor cell rescue, and developed a steroid responsive interstitial pneumonitis 10 weeks after stem cell infusion.

Isolation of virus-neutralizing RNAs from a large pool of random sequences

RNA and ribonuclease-resistant RNA analogs that bound and neutralized Rous sarcoma virus (RSV) were isolated from a large pool of random sequences by multiple cycles of in vitro selection using infectious viral particles. The selected RNA pool of RSV-binding sequences at a concentration of 0.16 microM completely neutralized the virus. Of 19 sequences cloned from the selected pool, 5 inhibited RSV infection. The selected RNA and RNA analogs were shown to neutralize RSV by interacting with the virus, rather than by adversely affecting the host cells. The selection of the anti-RSV RNA and RNA analogs by intact virions immediately suggests the potential application of this approach to develop RNA and RNA analogs as inhibitors of other viruses such as human immunodeficiency virus.

Oxidative stress-inducible protein tyrosine phosphatase in glomerulonephritis

Previously we found that rat mesangial cells express 3CH134/CL100 protein-tyrosine phosphatase (PTPase) in response to reactive oxygen intermediates (ROIs), and we now extend these studies to glomerulonephritis (GN), where ROI have been demonstrated to play a role. The rat homologue of 3CH134/CL100 was cloned from a rat macrophage cDNA library. The rat 3CH134/CL100 mRNA was strongly induced in the lung, liver, and heart the first day after birth, suggesting that hyperoxic adaption might be involved in the induction of the PTPase mRNA. In anti-glomerular basement membrane (GBM) antibody (Ab) GN in rats, the 3CH134/CL100 PTPase mRNA was expressed in glomeruli as early as 30 minutes after anti-GBM Ab injection. The 3CH134/CL100 mRNA expression was modulated by the ROI scavenger dimethylthiourea (DMTU), indicating that its induction was ROI related. In contrast to the glomerular lesion, PTPase mRNA expression was not induced in experimental tubulointerstitial nephritis. In situ hybridization suggested that mesangial and some infiltrating cells were the major glomerular cell sources of the PTPase mRNA. These results indicate that rat CCH134/CL100 PTPase is actively induced in glomeruli as part of an acute immune injury at least in part related to oxidative stress. PTPase induction in GN and potentially other forms of inflammation may play an important regulatory role in protein kinase signaling pathways.

Long-term hepatic adenovirus-mediated gene expression in mice following CTLA4Ig administration

Recombinant adenovirus vectors are efficient at transferring genes into somatic tissues but are limited for use in clinical gene therapy by immunologic factors that result in the rapid loss of gene expression and inhibit secondary gene transfer. This study demonstrates that systemic coadministration of recombinant adenovirus with soluble CTLA4Ig, which is known to block co-stimulatory signals between T cells and antigen presenting cells, leads to persistent adenoviral gene expression in mice without long-term immunosuppression. This form of immunotherapy greatly enhances the likelihood that recombinant adenovirus vectors will be useful for human gene therapy.

Expression and localization of inducible nitric oxide synthase in anti-Thy-1 glomerulonephritis

To elucidate a possible involvement of nitric oxide in the development of a mesangial proliferative glomerulonephritis induced by anti-Thy-1 antibody administration, glomerular expression of three isoforms of NO synthase (NOS), inducible NOS (iNOS), brain NOS, and endothelial NOS, was examined at both mRNA and protein levels by ribonuclease protection assay and immunofluorescence microscopy. Light microscopy showed an accumulation of polymorphonuclear leukocytes at 1 hour, lysis of mesangial cells at 1 day, a mesangial proliferative lesion at 4 to 10 days, and minimal residual glomerular lesions by 28 days. Ribonuclease protection assay showed that the glomerular expression of iNOS mRNA peaked at 1 hour and decreased thereafter. No substantial expression of iNOS mRNA was observed in normal glomeruli or in the nephritic glomeruli obtained at different time points (1, 4, 10, or 28 days). By immunofluorescence microscopy with a specific monoclonal antibody, an intense reaction for iNOS was demonstrated in a few cells in the glomeruli at 1 hour. Most of the iNOS-positive cells were identified as polymorphonuclear leukocytes. iNOS-positive cells were found less frequently in the glomeruli on days 1 and 4. Endothelial NOS mRNA was constitutively expressed in normal glomeruli and increased biphasically with two peaks at 1 hour and at 4 days or later; however, the peak expression was much less than that of iNOS mRNA at 1 hour. Expression of brain NOS mRNA was not detectable in either normal or nephritic glomeruli. These results show that iNOS is predominantly expressed in polymorphonuclear leukocytes accumulating at 1 hour in the glomeruli of anti-Thy-1 glomerulonephritis and suggest an involvement of NO in the initiation of the disease.

Delayed onset of hyponatremia after transsphenoidal surgery for pituitary adenomas

Hyponatremia is rarely reported as a delayed complication of transsphenoidal resection of pituitary adenoma. Usually attributed to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), hyponatremia causes nonspecific symptoms, often after hospital discharge. To clarify the frequency, presentation, and outcome of this poorly understood complication, we reviewed our database of 2297 patients who underwent transsphenoidal pituitary surgery between February 1971 and June 1993. Of 53 patients (2.3%) treated for symptomatic hyponatremia, 11 were excluded (2 received arginine vasopressin within 24 hours, 1 had untreated hypothyroidism, 4 had untreated adrenal insufficiency, and 4 had incomplete records). The remaining 42 patients (1.8%), 11 men and 31 women aged 21 to 79 years, presented 4 to 13 days (mean, 8 d) postoperatively with nausea and vomiting (20 patients), headache (18 patients), malaise (12 patients), dizziness (4 patients), anorexia (2 patients), and seizures (1 patient). Hyponatremia was unrelated to sex, age, adenoma type, tumor size, or glucocorticoid tapering. Although the clinical picture in our patients is consistent with SIADH, this was not supported by the antidiuretic hormone levels, which were normal or low-normal in the two patients in whom they were measured, suggesting the possibility that low serum sodium may not reflect SIADH. In all patients, hyponatremia resolved within 6 days (mean, 2 d); treatment consisted of salt replacement and mild fluid restriction in 37 patients and fluid restriction only in 4 (treatment unknown in 1). Delayed hyponatremia after transsphenoidal resection of pituitary adenoma is not as rare as previously thought, nor is it necessarily associated with SIADH or with hypoadrenalism during glucocorticoid tapering.(ABSTRACT TRUNCATED AT 250 WORDS)

Identification of the alpha 3 chain of type IV collagen as the common autoantigen in antibasement membrane disease and Goodpasture syndrome

Antiglomerular basement membrane (GBM) antibodies can cause glomerulonephritis or pulmonary hemorrhage by themselves or Goodpasture syndrome when they occur together. It is unknown if variations in antibody reactivity contribute to the different patterns of organ involvement seen in this disease. This study examines the reactivity of the alpha 1-alpha 6 NC1 domains of Type IV collagen, the putative autoantigen, in sera from patients with anti-GBM antibodies after various clinical presentations of lung hemorrhage and renal injury. Serum or plasma containing anti-GBM antibodies from 35 patients with combined glomerulonephritis and pulmonary hemorrhage, 19 with glomerulonephritis alone, and 4 with pulmonary hemorrhage alone were compared with samples from 19 normal controls and 32 patients with other kidney diseases. Four different immunologic assays were performed with bovine alpha 1-alpha 6(IV) and recombinant human type alpha 1-alpha 5(IV) collagen NC1 domains. The study found that the anti-GBM antibodies from all patients reacted with the alpha 3(IV) NC1 (85% exclusively). Additional limited reactivity with the alpha 1(IV) NC1 and alpha 4(IV) NC1 was found in 15 and 3%, respectively. This non-alpha 3(IV) NC1 reactivity was most frequent in the patients with anti-GBM antibodies and glomerulonephritis alone. None of the patients had reactivity to other basement membrane components like laminin, fibronectin, heparan sulfate proteoglycan, entactin, or the 7S and triple helical fragments of Type IV collagen. The observed alpha-chain NC1 reactivity was confined to patients with anti-GBM antibodies with no additional reactivities detected among a large number of other kidney diseases controls. The correlation of alpha 1-alpha 6(IV) NC1 reactivity in a large number of patients with anti-GBM antibodies defined by classic assays definitively establishes that reactivity to alpha 3(IV) NC1 domains is both sufficient and necessary for the expression of autoimmune disease directed to the NC1 domain of Type IV collagen. On the basis of the evidence, the classification of antibasement membrane disease and Goodpasture syndrome as anti-Type IV collagen disease is proposed.

Selective type IV collagen defects in the urothelial basement membrane in interstitial cystitis

PURPOSE

The study sought to identify changes in the urothelial basement membrane (UBM) associated with interstitial cystitis (IC).

MATERIALS AND METHODS

Immunohistochemical assessment of bladder biopsies from IC patients and controls was compared with clinical and histologic findings.

RESULTS

Selective decreases or loss of type IV collagen staining, but not laminin, were found in the UBM of 5 of 11 IC patients with no change in type IV collagen staining of other bladder wall sites.

CONCLUSIONS

The loss of type IV collagen may represent a primary or secondary event and could alter the UBM's role in permeability, thereby contributing to the pathogenesis of IC in the subset of IC patients exhibiting this change.

Positionally independent and exchangeable late budding functions of the Rous sarcoma virus and human immunodeficiency virus Gag proteins

The Gag proteins of Rous sarcoma virus and human immunodeficiency virus (HIV) each contain a function involved in a late step in budding, defects in which result in the accumulation of these molecules at the plasma membrane. In the Rous sarcoma virus Gag protein (Pr76gag), this assembly domain is associated with a PPPY motif, which is located at an internal position between the MA and CA sequences. This motif is not contained anywhere within the HIV Gag protein (Pr55gag), and the MA sequence is linked directly to CA. Instead, a late assembly function of HIV has been associated with the p6 sequence situated at the C terminus of Gag. Here we demonstrate the remarkable finding that the late assembly domains from these two unrelated Gag proteins are exchangeable between retroviruses and can function in a positionally independent manner.

Pituitary adenoma as an unsuspected clival tumor

Pituitary adenomas are common tumors that account for about 10% of intracranial neoplasms. Most arise from the adenohypophysis and are confined to the region of the sella turcica. Other sites may be involved as a result of extension, infiltration, or ectopic location. However, posterior extension or ectopic involvement of the clivus of the sphenoid and occipital bones is rare. Seven patients with destructive clival masses were referred to our institution with presumptive diagnoses of chordomas. In all cases, histologic workup revealed pituitary adenomas. Because they represent a subset of adenomas, the histologic features of the tumors were studied, and the clinical histories of the patients were reviewed. Five of the patients were men, aged 31 to 67 years, and two were women, aged 55 and 67 years. Four patients had extremely high plasma concentrations of prolactin (8,132-22,424 ng/ml, nl < 15). Four tumors resembled usual sellar adenomas; however, three exhibited nuclear pleomorphism, mitotic figures, and other morphologic features, suggesting alternate diagnoses. Three required immunoperoxidase stains in addition to those for pituitary hormones, and three required electron microscopy for diagnosis. Destructive invasion of the clivus by pituitary adenomas is rare, and anaplastic features of some of the tumors may lead to difficult diagnoses.

Medulloblastoma in adults

PURPOSE

To examine the relationship between extent of disease and outcome in adults with medulloblastoma.

METHODS AND MATERIALS

We reviewed the records of all patients over 15 years old with newly diagnosed or recurrent medulloblastoma treated by or referred to the University of California, San Francisco, and recorded demographic characteristics, clinical symptoms, radiographic findings, extent of resection, staging, myelography, computerized tomography (CT) scans or magnetic resonance (MR) images of the spine, histopathological assessment, treatment received, treatment response, recurrence patterns, and survival duration.

RESULTS

A total of 47 patients were identified, 26 of whom were designated "poor-risk" because they had < 75% removal of tumor, metastatic disease, or brain-stem or leptomeningeal invasion. All patients had radiation therapy; 32 had adjuvant chemotherapy. Twenty-two patients (47%) died of tumor progression, 19 are progression-free, and 6 are alive with disease. The median survival time was 282 weeks in poor-risk patients and has not been reached in good-risk patients. Overall and disease-free 5-year survival rates differed significantly between the two groups (81% vs. 54%, p = 0.03 and 58% vs. 38%, p = 0.05, respectively). Tumors most often recurred in the posterior fossa. The median survival time from recurrence was 77 weeks (range 44 to 89 weeks).

CONCLUSION

These findings are similar to those reported for children. Therefore, staging and treatment in adults should be approached the same way as in children: staging should include cerebrospinal fluid assessment and spinal imaging. Treatment should be based on staging, and should include craniospinal irradiation; additional chemotherapy should probably be reserved for poor-risk patients.

Fetal dose estimates for radiotherapy of brain tumors during pregnancy

PURPOSE

To determine clinically the fetal dose from irradiation of brain tumors during pregnancy and to quantitate the components of fetal dose using phantom measurements.

METHODS AND MATERIALS

Two patients received radiotherapy during pregnancy for malignant brain tumors. Case 1 was treated with opposed lateral blocked 10 x 15 cm fields and case 2 with 6 x 6 cm bicoronal wedged arcs, using 6 MV photons. Fetal dose was measured clinically and confirmed with phantom measurements using thermoluminescent dosimeters (TLDs). Further phantom measurements quantitated the components of scattered dose.

RESULTS

For case 1, both clinical and phantom measurements estimated fetal dose to be 0.09% of the tumor dose, corresponding to a total fetal dose of 0.06 Gy for a tumor dose of 68.0 Gy. Phantom measurements estimated that internal scatter contributed 20% of the fetal dose, leakage 20%, collimator scatter 33%, and block scatter 27%. For case 2, clinical and phantom measurements estimated fetal dose to be 0.04% of the tumor dose, corresponding to a total fetal dose of 0.03 Gy for a tumor dose of 78.0 Gy. Leakage contributed 74% of the fetal dose, internal scatter 13%, collimator scatter 9%, and wedge scatter 4%.

CONCLUSIONS

When indicated, brain tumors may be irradiated to high dose during pregnancy resulting in fetal exposure < 0.10 Gy, conferring an increased but acceptable risk of leukemia in the child, but no other deleterious effects to the fetus after the fourth week of gestation. For our particular field arrangements and linear accelerators, internal scatter contributed a small component of fetal dose compared to leakage and scatter from the collimators and blocks, and 18 MV photons resulted in a higher estimated fetal dose than 6 MV photons due to increased leakage and collimator scatter. These findings are not universal, but clinical and phantom TLD measurements estimate fetal dose accurately for energies < 10 MV and should be taken for each pregnant patient considered for treatment to confirm and document acceptable dose.

Imaging metastatic testicular germ cell tumours with 18FDG positron emission tomography: prospects for detection and management

The aim of this study was to investigate the role of positron emission tomography (PET) with [18F]fluoro-2-deoxyglucose (18FDG) in metastatic testicular germ cell tumours. Twenty-one patients with stage II-IV testicular germ cell tumours were imaged by PET with a multiwire proportional chamber PET system and 18FDG. Avid 18FDG uptake was seen in metastatic disease from primary seminoma and malignant teratoma. Normal tissue uptake was seen in differentiated teratoma or necrotic, fibrotic tissue. 18FDG standard uptake values and tumour to normal tissue ratios were 6.0 +/- 1.4 and 1.7 +/- 0.4 (mean +/- 1SD), respectively, for malignant tissue. Reduction of 18FDG tumour to normal tissue ratios from pre-treatment to on-treatment scans was predictive of response (n = 3). No significant reduction in 18FDG uptake was seen in patients not responding to therapy (n = 2). These results suggest a role for 18FDG PET in the detection and management of metastatic testicular germ cell tumours.

Extrasellar, intracavernous sinus adrenocorticotropin-releasing adenoma causing Cushing's disease

This report describes a patient with pituitary-dependent Cushing's disease who had a preoperative ACTH gradient to the left at the level of the cavernous sinus. Intraoperatively, an adenoma was found entirely within the left cavernous sinus, with no direct connection to the pituitary gland. To our knowledge, such a tumor has not been reported previously. This case has implications for the diagnosis, treatment, and follow-up of patients with pituitary-dependent Cushing's disease. The presence of an entirely extrasellar ACTH-releasing adenoma in the cavernous sinus could explain why pituitary-dependent Cushing's disease may persist postoperatively, even after total hypophysectomy. The diagnosis of an intracavernous tumor can be established by cavernous sinus venography. An extrasellar intracavernous adenoma can be diagnosed intraoperatively after careful negative exploration of the sellar contents followed by incision of the cavernous sinus on the side of the ACTH gradient established by venous sampling.

Radiation therapy and bromodeoxyuridine chemotherapy followed by procarbazine, lomustine, and vincristine for the treatment of anaplastic gliomas

PURPOSE

To conduct a Phase II study to evaluate the long-term efficacy and safety of radiotherapy combined with intravenous bromodeoxyuridine for patients with anaplastic glioma tumors.

METHODS AND MATERIALS

Between 1983 and 1987, study patients received 1.7-1.8 Gy radiation once a day, Monday through Friday, to a total dose of 60 Gy. On the Thursday prior to beginning radiotherapy and for the next 5 weeks (6 weeks total), patients received a continuous 96 h intravenous infusion of bromodeoxyuridine at 0.8 g/m2/24 h; following radiotherapy, patients received procarbazine, lomustine (CCNU), and vincristine (PCV) for 1 year or until tumor progressed.

RESULTS

One-hundred thirty eight patients (median age, 43 years) were evaluable for analysis. Estimated 4-year survival for the anaplastic astrocytoma (AA) stratum (n = 116) is 46%. For the astrocytoma (ASTRO) stratum (n = 22), the 6-year survival is estimated at 79%. Estimated 4-year progression-free survival for AAs is 42%, and for ASTROs, 68%. Whole brain irradiation was used in 23% and limited-field irradiation in 77%; patients receiving limited-field irradiation had a better survival rate (p = 0.07). Total tumor resection was performed in 15%, partial resection in 53%, and biopsy only in 32%. For the 81 patients with tumor recurrence, 34 (42%) are known to have received additional treatment(s). For AA, fits of the Cox proportional hazards regression model showed that covariates individually predictive of survival were younger age (p < 0.001), Karnofsky performance score (p = 0.10). Major toxicities were rash during Weeks 1 through 6 requiring dose modification in 14%, Grade > or = III leukopenia in 18%, and Grade > or = III thrombocytopeni in 9%.

CONCLUSION

The study suggests that the bromodeoxyuridine-radiotherapy-PCV, compared with other published therapies, can improve progression-free survival, and aggressive treatment of ASTRO patients can lead to substantial increases in survival compared to published survival data.

Involvement of reactive oxygen intermediates in cyclooxygenase-2 expression induced by interleukin-1, tumor necrosis factor-alpha, and lipopolysaccharide

Reactive oxygen intermediates (ROIs) play an important role in inflammatory processes as mediators of injury and potentially in signal transduction leading to gene expression. Cyclooxygenase (COX) is a rate-limiting enzyme in prostanoid biosynthesis, and its recently cloned inducible form, COX-2, is induced by proinflammatory cytokines. This study linked ROIs to the signaling pathways that induce COX-2 expression. The hydroxyl radical scavengers DMSO (1%), as well as di- and tetramethylthiourea, inhibited IL-1-, TNF alpha-, and LPS-induced COX-2 expression in rat mesangial cells. The suppression of COX-2 mRNA expression correlated with the COX-2 protein level. In comparison with the prolonged induction of the inducible gene encoding protein-tyrosine phosphatase by hydrogen peroxide, the COX-2 gene was only transiently induced. Protein-tyrosine phosphatase is also induced by heat shock and chemical stress, whereas COX-2 is not. Superoxide was a more potent inducer for COX-2 than hydrogen peroxide. In addition, NADPH stimulated COX-2 expression, and an inhibitor of NADPH oxidase blocked COX-2 expression induced by TNF alpha. COX-2 and KC gene expression costimulated by IL-1 were inhibited differentially by the scavengers. These studies demonstrate that oxidant stress is a specific and important inducer of COX-2 gene expression. This induction may contribute to the deleterious amplification of prostanoids in inflammation and compound the direct effects of ROI production.

Pituitary tumors. Current concepts in diagnosis and management

Diagnostic advances have resulted in earlier and more frequent recognition of pituitary tumors. Pituitary tumors cause problems owing to the hormones they secrete or the effects of an expanding sellar mass--hypopituitarism, visual field abnormalities, and neurologic deficits. Prolactin-secreting tumors (prolactinomas), which cause amenorrhea, galactorrhea, and hypogonadism, constitute the most common type of primary pituitary tumors, followed by growth hormone-secreting tumors, which cause acromegaly, and corticotropin-secreting tumors, which cause Cushing's syndrome. Hypersecretion of thyroid-stimulating hormone, the gonadotrophins, or alpha-subunits is unusual. Nonfunctional tumors currently represent only 10% of all clinically diagnosed pituitary adenomas, and some of these are alpha-subunit-secreting adenomas. Insights into the pathogenesis and biologic behavior of these usually benign tumors have been gained from genetic studies. We review some of the recent advances and salient features of the diagnosis and management of pituitary tumors, including biochemical and radiologic diagnosis, transsphenoidal surgery, radiation therapy, and medical therapy. Each type of lesion requires a comprehensive but individualized treatment approach, and regardless of the mode of therapy, careful follow-up is essential.

Modulation of neutrophil influx in glomerulonephritis in the rat with anti-macrophage inflammatory protein-2 (MIP-2) antibody

The role of the chemokine, macrophage inflammatory protein-2 (MIP-2), during anti-glomerular basement membrane (GBM) antibody (Ab) glomerulonephritis (GN) was studied. Rat MIP-2 cDNA had been cloned previously. Recombinant rat MIP-2 (rMIP-2) from Escherichia coli exhibited neutrophil chemotactic activity and produced neutrophil influx when injected into the rat bladder wall. By using a riboprobe derived from the cDNA and an anti-rMIP-2 polyclonal Ab, MIP-2 was found to be induced in glomeruli with anti-GBM Ab GN as mRNA by 30 min and protein by 4 h, with both disappearing by 24 h. The expression of MIP-2 correlated with glomerular neutrophil influx. A single dose of the anti-MIP-2 Ab 30 min before anti-GBM Ab was effective in reducing neutrophil influx (40% at 4 h, P < 0.01) and periodic acid-Schiff deposits containing fibrin (54% at 24 h, P < 0.01). The anti-rMIP-2 Ab had no effect on anti-GBM Ab binding (paired-label isotope study). Functional improvement in the glomerular damage was evidenced by a reduction of abnormal proteinuria (P < 0.05). These results suggest that MIP-2 is a major neutrophil chemoattractant contributing to influx of neutrophils in Ab-induced glomerular inflammation in the rat.

Pediatric pituitary adenomas

Previous series of pediatric pituitary adenomas have been small and have not been analyzed by age group. We analyzed the frequency, manifestation, course, and biology of these tumors before, during, and after puberty in 136 children younger than 20 years old at surgery, identified by review of 2230 patients treated from 1969 to 1993. Tumors were classified by clinical phenotype. Adrenocorticotropic hormone-releasing adenomas were most common before puberty, and prolactinomas were most common during and after. The frequencies of adrenocorticotropic hormone-releasing adenomas, prolactinomas, and endocrine-inactive adenomas differed from those in adults. Growth arrest was common with all types except growth hormone (GH)-releasing adenomas; menstrual irregularities were common with all but adenomas causing Nelson syndrome. Among girls with prolactinomas, the preoperative duration of primary amenorrhea was longer than that of other symptoms. Tumor size differed by adenoma type. Serum hormone levels shortly after surgery correlated with the recurrence of prolactinomas and GH-releasing adenomas. The prolactinoma size correlated with the maximum preoperative serum prolactin level; boys had larger tumors and higher preoperative and postoperative prolactin levels. We conclude that pediatric pituitary adenomas vary in size, age at symptom onset, and frequency before, during, and after puberty. Most adenomas can cause menstrual irregularities, and primary amenorrhea should prompt investigation of the sella. Growth arrest is common with all adenomas except GH-releasing adenomas. Serum prolactin and GH levels measured at 1 to 5 days after surgery indicate the risk of recurrence of prolactinomas and GH-releasing adenomas, respectively.

Effects of endotoxin in the lungs of neonatal rats: age-dependent impairment of the inflammatory response

Age-dependent maturation of the intrapulmonary inflammatory responses to bacterial lipopolysaccharide (LPS) was studied because nosocomial gram-negative infections cause morbidity in newborn infants. Escherichia coli LPS or live E. coli were injected into the airways of neonatal or adult rats; intrapulmonary recruitment of leukocytes was measured 6 h later. Neonates showed age- and dose-dependent impairment of intrapulmonary neutrophil recruitment after intratracheal administration of LPS or live E. coli that persisted for the first 28 days of life. Neonatal and adult alveolar macrophages released similar amounts of neutrophil chemotactic activity and tumor necrosis factor in response to incubation with LPS in vitro. Treatment of neonates with intratracheal or systemic interferon-gamma did not augment the response to LPS. Thus, intrapulmonary inflammatory responses to LPS and gram-negative bacteria are impaired early in life and do not approach adult levels until approximately 4 weeks of age.

Surgery for low-grade glioma: rationale for early intervention

We feel that early surgical intervention is appropriate in the patient who presents with a clinical picture suggesting a low-grade glioma. Neuroimaging is not adequate to make an accurate diagnosis of the underlying pathology. Tumor tissue sampling allows a more specific diagnosis and testing for biologic factors such as the proliferative potential of the lesion. Surgical diagnosis allows a disease-specific therapy to be more appropriately prescribed to the patient, including the option for no further treatment, radiotherapy, and/or chemotherapy. There is compelling early data that suggest that the extent of surgery and the postoperative tumor volume will be predictive of outcome in at least some tumor types. We encourage participation of physician and patients in well-designed clinical trails that will ultimately answer the many questions that remain about these unique diseases.

Diminished expression of CD40 ligand by activated neonatal T cells

CD40 and CD40 ligand (gp39) mediate contact-dependent T-B cell interaction. We determined the expression of CD40 ligand by activated neonatal T cells and the response of neonatal B cells when activated through CD40. Although expression of CD40 ligand peaked simultaneously in both activated adult and neonatal cells, neonatal T cells expressed significantly less CD40 ligand surface protein and mRNA than adult T cells. Activated thymocytes also expressed far less CD40 ligand than adult T cells. Consistent with these results, activated neonatal T cells exhibited less helper function than activated adult T cells. Neonatal T cells primed and restimulated in vitro expressed CD40 ligand in amounts comparable with adult T cells and provided B cell help more effectively. This suggests that the poor expression of CD40 ligand reflects antigenic naiveté rather than an intrinsic defect of neonatal T cells. Neonatal B cells cultured with soluble CD40 ligand (sgp39) and IL-10 produced IgM in amounts comparable with adult cells, but much less IgG and IgA. Nevertheless, neonatal B cells were capable of proliferation and class switching, since sgp39 and IL-4 induced proliferation and IgE production comparable to adult B cells and production of modest amounts of IgG. Together, these results indicate that diminished CD40 ligand expression, along with decreased production of lymphokines, may be responsible, at least in part, for the transient immunodeficiency observed in human neonates.

Cushing's disease. Therapy of pituitary adenomas

Treatment of Cushing's disease has evolved over the past 20 years from the era of bilateral adrenalectomy to the current era of pituitary microsurgery. Therapy directed to the pituitary gland is currently the first approach in Cushing's disease and transphenoidal exploration of the sellar contents is the procedure of choice. Tumor localization and pituitary surgery are reviewed. Pituitary radiotherapy, pharmacologic inhibition of ACTH secretion, and Nelson's syndrome are also discussed.

Radiation-induced telangiectasia in the brain simulates cryptic vascular malformations at MR imaging

PURPOSE

To analyze the magnetic resonance (MR) imaging, clinical, and pathologic features of radiation-induced telangiectasia of the brain.

MATERIALS AND METHODS

The clinical and radiation therapy records were reviewed of 20 patients who developed focal hypointense lesions on T2-weighted MR images obtained after radiation therapy of the central nervous system. Pathologic material was reviewed in six patients.

RESULTS

Eleven patients had solitary lesions, and nine had multiple foci on MR images. Fourteen of the 20 patients were less than 20 years old. The appearance ranged from small hypointense foci to larger regions of acute hemorrhage. Hematomas occurred at the site of a previously identified focus of T2 shortening in five patients. Pathologic findings included ectatic thin-walled vessels surrounded by hemosiderin and gliosis, with minimal evidence of necrosis.

CONCLUSION

Radiation-induced telangiectasia in the brain results in varying amounts of hemorrhage and, occasionally, parenchymal hematomas, and may appear similar to cryptic vascular malformations on T2-weighted MR images.

Protein C inhibitor is expressed in tubular cells of human kidney

Protein C inhibitor (PCI) is a serpin that inhibits a number of proteases. PCI is found in urine and binds to kidney epithelial cells. To determine if kidney is a source of PCI, cDNA was produced from human kidney total RNA. Sequencing and restriction mapping showed identity between kidney and liver PCI cDNA sequences. Similar cDNAs were obtained from rhesus monkey kidney and liver RNAs. Conditioned medium from the rhesus monkey kidney cell line CCL7.1 was analyzed on immunoblots, showing a 57,000-D protein band that comigrated with human plasma PCI. Immunohistochemical staining and in situ hybridization of human kidney tissue sections showed that kidney PCI antigen and RNA were confined to tubular cells. The findings are consistent with the idea that PCI is synthesized and localized in kidney tissue where it may provide protease inhibitory activity and suggest that complexes of PCI with urokinase found in human urine may be produced locally in the kidney.

Meningiomas: genetics, malignancy, and the role of radiation in induction and treatment. The Richard C. Schneider Lecture

The author reviews the molecular genetics, pathology, and cell kinetics of meningiomas and the role that regional multiplicity in the dura mater may play in their recurrence. Malignant and radiation-induced meningiomas are discussed, with summaries of series of 60 patients with frankly malignant lesions treated over a period of 22 years at the University of California, San Francisco, and of 10 patients with meningiomas induced by high-dose radiation therapy. Reviewing a 23-year series of 140 patients with subtotally removed meningiomas who were treated post-operatively with radiation, the author recommends that, with meticulous technique, irradiation is effective in preventing the regrowth of subtotally removed benign meningiomas and of all malignant meningiomas. Adoption of both the microscopical cytological grading system proposed by Jääskeläinen's group in Helsinki and the classification of operations proposed by Donald Simpson is also recommended. Wide removal of dura adjacent to meningioma reduces the risk of recurrence, and determination of the bromodeoxyuridine labeling index provides a valid basis for planning treatment and follow-up evaluations. Increased awareness is necessary for early recognition of radiation-induced meningiomas in patients at risk for developing such tumors. For meningiomas in such sites as the parasellar region and the posterior fossa, conservative removal of tumor followed by irradiation is advocated in preference to a radical operation that may cause neurological injury without being curative.

Differentiation of the T helper phenotypes by analysis of the methylation state of the IFN-gamma gene

Th1 and Th2 CD4+ T cell clones have been defined by their ability to produce different lymphokines. However, the processes by which CD4+ T cells differentially regulate lymphokine gene expression have not been well defined. In this report, we demonstrate that the methylation status of a CpG dinucleotide contained within a TATA proximal regulatory element of the IFN-gamma promoter correlates with the transcription of the gene. In murine Th1 clones and two human CD4+ Th0 clones, this site is either completely or partially hypomethylated, whereas in murine Th2 clones this site is &gt; 98% methylated. Treatment of murine Th2 clones with 5-azacytidine, an agent that inhibits methylation of the DNA, converts these cells to IFN-gamma producers. Additional targets for methylation outside the transcriptional control regions of the IFN-gamma genetic locus were found to be hypomethylated in Th2 cells but not in Th1 cells. Electrophoretic mobility shift assays (EMSA) revealed at least five distinct protein-DNA complexes that are formed with an oligonucleotide containing the IFN-gamma promoter TATA proximal regulatory element, and in vitro methylation of this site results in a loss of these three complexes. Furthermore, a comparison of nuclear extracts prepared from Th1 and Th2 clones revealed that the EMSA patterns were qualitatively similar but differed quantitatively. In addition, transient transfection of a murine IFN-gamma promoter-chloramphenicol acetyl transferase (CAT) gene construct into both Th1 and Th2 clones produced CAT activity that was not inducible by anti-CD3, indicating that hypomethylation per se of the promoter alone is not sufficient for inducible gene expression.

Differentiation of the T helper phenotypes by analysis of the methylation state of the IFN-gamma gene

Th1 and Th2 CD4+ T cell clones have been defined by their ability to produce different lymphokines. However, the processes by which CD4+ T cells differentially regulate lymphokine gene expression have not been well defined. In this report, we demonstrate that the methylation status of a CpG dinucleotide contained within a TATA proximal regulatory element of the IFN-gamma promoter correlates with the transcription of the gene. In murine Th1 clones and two human CD4+ Th0 clones, this site is either completely or partially hypomethylated, whereas in murine Th2 clones this site is > 98% methylated. Treatment of murine Th2 clones with 5-azacytidine, an agent that inhibits methylation of the DNA, converts these cells to IFN-gamma producers. Additional targets for methylation outside the transcriptional control regions of the IFN-gamma genetic locus were found to be hypomethylated in Th2 cells but not in Th1 cells. Electrophoretic mobility shift assays (EMSA) revealed at least five distinct protein-DNA complexes that are formed with an oligonucleotide containing the IFN-gamma promoter TATA proximal regulatory element, and in vitro methylation of this site results in a loss of these three complexes. Furthermore, a comparison of nuclear extracts prepared from Th1 and Th2 clones revealed that the EMSA patterns were qualitatively similar but differed quantitatively. In addition, transient transfection of a murine IFN-gamma promoter-chloramphenicol acetyl transferase (CAT) gene construct into both Th1 and Th2 clones produced CAT activity that was not inducible by anti-CD3, indicating that hypomethylation per se of the promoter alone is not sufficient for inducible gene expression.

An assembly domain of the Rous sarcoma virus Gag protein required late in budding

The Gag protein of Rous sarcoma virus has the ability to direct particle assembly at the plasma membrane in the absence of all the other virus-encoded components. An extensive deletion analysis has revealed that very large regions of this protein can be deleted without impairing budding and has suggested that the essential functions map to three discrete regions. In the studies reported here, we establish the location of assembly domain 2 (AD2) within the proline-rich p2b sequence of this Gag protein. AD2 mutants lacking the p2b sequence were completely defective for particle release even though their Gag proteins were tightly associated with the membrane fraction and exhibited high levels of protease activity. Mutations that inactivate the viral protease did not restore budding to wild-type levels for these mutants, indicating that the defect is not due simply to a loss of protease regulation. AD2 mutants could be rescued into dense particles in genetic complementation assays, indicating that their defect is not due to a gross alteration of the overall conformation of the protein and that the assembly function is not needed on every Gag molecule in the population. Several mutants with amino acid substitutions in the p2b sequence were found to have an intermediate capacity for budding. Inactivation of the protease of these mutants stabilized the Gag polyprotein within the cells and allowed an increase in particle release; however, the rate of budding remained slow. We favor the idea that AD2 is a dynamic region of movement, perhaps serving as a molecular hinge to allow the particle to emerge from the surface of the cell during budding.

Correlation between the bromodeoxyuridine labeling index and the MIB-1 and Ki-67 proliferating cell indices in cerebral gliomas

BACKGROUND

Recently, it has been shown that heating paraffin embedded tumor sections in a microwave oven can reactivate an epitope of Ki-67 protein that is recognized by the monoclonal antibody MIB-1. With this technique, a close correlation was shown between the bromodeoxyuridine labeling index (BUdR LI) and the MIB-1 proliferating cell index (PCI) in corresponding regions of glioblastomas.

METHODS

The reliability of the MIB-1 PCI as a marker of proliferation was evaluated in 90 cerebral gliomas. The MIB-1 immunostaining of ethanol-fixed, paraffin embedded sections of 23 moderately anaplastic astrocytomas, 22 highly anaplastic astrocytomas, 30 glioblastomas, and 15 mixed malignant gliomas was compared with the BUdR LI and, in some cases, the Ki-67 PCI.

RESULTS

MIB-1 positive cells were detected easily in the majority of the cases, and the MIB-1 immunostaining was often superior to that of Ki-67 in individual tumors. The MIB-1 PCI was significantly higher than the Ki-67 PCI and the BUdR LI. Linear-regression analysis showed significant correlations among the three indices. The MIB-1 PCI was correlated with the BUdR LI in each group of the astrocytic tumors and mixed malignant gliomas; the MIB-1 PCI was approximately 2.4-2.8 times higher than the BUdR LI.

CONCLUSIONS

The close correlation between the MIB-1 PCI and the in vivo BUdR LI in serial sections of glioma subtypes suggests that MIB-1 immunostaining is a useful technique for analyzing the proliferative potential of individual gliomas.