Combinatorial ASO-mediated therapy with low dose SMN and the protective modifier Chp1 is not sufficient to ameliorate SMA pathology hallmarks.

Spinal muscular atrophy (SMA) is a devastating genetically inherited neuromuscular disorder characterized by the progressive loss of motor neurons in the spinal cord, leading to muscle atrophy and weakness. Although SMA is caused by homozygous mutations in SMN1, the disease severity is mainly determined by the copy number of SMN2, an almost identical gene that produces ~10% correctly spliced SMN transcripts. Recently, three FDA- and EMA-approved therapies that either increase correctly spliced SMN2 transcripts (nusinersen and risdiplam) or replace SMN1 (onasemnogen abeparvovec-xioi) have revolutionized the clinical outcome in SMA patients. However, for severely affected SMA individuals carrying only two SMN2 copies even a presymptomatic therapy might be insufficient to fully counteract disease development. Therefore, SMN-independent compounds supporting SMN-dependent therapies represent a promising therapeutic approach. Recently, we have shown a significant amelioration of SMA disease hallmarks in a severely affected SMA mouse carrying a mutant Chp1 allele when combined with low-dose of SMN antisense oligonucleotide (ASO) treatment. CHP1 is a direct interacting partner of PLS3, a strong protective modifier of SMA. Both proteins ameliorate impaired endocytosis in SMA and significantly restore pathological hallmarks in mice. Here, we aimed to pharmacologically reduce CHP1 levels in an ASO-based combinatorial therapy targeting SMN and Chp1. Chp1 modulation is a major challenge since its genetic reduction to ~50% has shown to ameliorate SMA pathology, while the downregulation below that level causes cerebellar ataxia. Efficacy and tolerability studies determined that a single injection of 30 µg Chp1-ASO4 in the CNS is a safe dosage that significantly reduced CHP1 levels to ~50% at postnatal day (PND)14. Unfortunately, neither electrophysiological predictors such as compound muscle action potential (CMAP) or motor unit number estimation (MUNE) nor histological hallmarks of SMA in neuromuscular junction (NMJ), spinal cord or muscle were ameliorated in SMA mice treated with Chp1-ASO4 compared to CTRL-ASO at PND21. Surprisingly, CHP1 levels were almost at control level 4-weeks post injection, indicating a rather short-term effect of the ASO. Therefore, we re-administrated Chp1-ASO4 by i.c.v. bolus injection at PND28. However, no significant improvement of SMA hallmarks were seen at 2 month-of-age either. In conclusion, in contrast to the protective effect of genetically-induced Chp1 reduction on SMA, combinatorial therapy with Chp1- and SMN-ASOs failed to significantly ameliorate the SMA pathology. Chp1-ASOs compared to SMN-ASO proved to have rather short-term effect and even reinjection had no significant impact on SMA progression, suggesting that further optimization of the ASO may be required to fully explore the combination.

Has PET/CT a role in the characterization of indeterminate lung lesions on staging CT in colorectal cancer? A prospective study.

PURPOSE: CT has been found superior to chest x-ray to detect lung malignances. However, indeterminate lung lesions (ILL) are found in 4-42% by using CT in staging colorectal cancer (CRC) patients. Our aim was to examine the frequency of ILL on staging CT and the rate of the ILL being malignant, and to investigate if PET/CT was useful in pointing out the malignant cases. METHODS: A prospective analysis of 238 consecutive patients operated for CRC followed median 24 months. All the patients had a preoperative staging CT. Patients with ILL had a PET/CT scan performed 3 months postoperatively and low dose chest CT performed 6, 12, 18 and 24 months postoperatively. RESULTS: Twenty percent of the patients had ILL. Four of these patients (8.5%) had lung metastases detected median 9 months postoperatively, while 2 (4.3%) had other lung malignancies. One patient had TB. In patients with normal staging chest CT 10 of the 185 patients (5.4%) developed lung metastases detected median 16 months postoperatively. This was significantly later than in patients with ILL (p < 0.001), but with regard to the number of patients developing lung metastases no significant difference was found between the groups (p = 0.12). CONCLUSIONS: Even though a relative low number of ILL turn out to be malignant it seems advisable to use PET/CT scan in the follow-up to detect lung metastases as early as possible to better the prognosis. For the same reason all CRC patients should have chest CT included in their follow-up 6-12 months postoperatively.

Automatic, three-segment, MR-based attenuation correction for whole-body PET/MR data.

PURPOSE: The combination of positron emission tomography (PET) and magnetic resonance (MR) tomography in a single device is anticipated to be the next step following PET/CT for future molecular imaging application. Compared to CT, the main advantages of MR are versatile soft tissue contrast and its capability to acquire functional information without ionizing radiation. However, MR is not capable of measuring a physical quantity that would allow a direct derivation of the attenuation values for high-energy photons. METHODS: To overcome this problem, we propose a fully automated approach that uses a dedicated T1-weighted MR sequence in combination with a customized image processing technique to derive attenuation maps for whole-body PET. The algorithm automatically identifies the outer contour of the body and the lungs using region-growing techniques in combination with an intensity analysis for automatic threshold estimation. No user interaction is required to generate the attenuation map. RESULTS: The accuracy of the proposed MR-based attenuation correction (AC) approach was evaluated in a clinical study using whole-body PET/CT and MR images of the same patients (n = 15). The segmentation of the body and lung contour (L-R directions) was evaluated via a four-point scale in comparison to the original MR image (mean values >3.8). PET images were reconstructed using elastically registered MR-based and CT-based (segmented and non-segmented) attenuation maps. The MR-based AC showed similar behaviour as CT-based AC and similar accuracy as offered by segmented CT-based AC. Standardized uptake value (SUV) comparisons with reference to CT-based AC using predefined attenuation coefficients showed the largest difference for bone lesions (mean value ± standard variation of SUV(max): -3.0% ± 3.9% for MR; -6.5% ± 4.1% for segmented CT). A blind comparison of PET images corrected with segmented MR-based, CT-based and segmented CT-based AC afforded identical lesion detectability, but slight differences in image quality were found. CONCLUSION: Our MR-based attenuation correction method offers similar correction accuracy as offered by segmented CT. According to the specialists involved in the blind study, these differences do not affect the diagnostic value of the PET images.

Autoantibodies to double-stranded DNA--intermethod comparison between four commercial immunoassays and a research biosensor-based device.

Patients with systemic lupus erythematosus (SLE) often develop a wide variety of serological manifestations including the presence of antibodies to double-stranded DNA (anti-dsDNA). Positivity for anti-dsDNA constitutes one of the laboratory criteria for the diagnosis of SLE and is therefore clinically relevant. We analyzed the diagnostic accuracies of four commercial anti-dsDNA immunoassays and compared the results with a recently established surface plasmon resonance (SPR) biosensor chip with covalently chip-immobilized dsDNA. The anti-dsDNA measurements were performed retrospectively in 50 patients with clinically proven SLE, 39 patients with other autoimmunopathies and 20 healthy controls. Data were evaluated by Receiver-Operator Characteristic (ROC) analysis, with special regard to SLE patients suffering from lupus nephritis. The ROC analyses for the four immunoassays and the SPR biosensor resulted in the following area-under-the-curve (AUC) and diagnostic efficiency (DE) values in descending order: Bindazyme AUC, 0.89; DE, 0.88; ELiA AUC, 0.89; DE, 0.86; SPR biosensor AUC, 0.82; DE, 0.80; Farrzyme AUC, 0.77; DE, 0.77; Farr AUC, 0.77; DE, 0.70. When considering the 22 nephritis SLE patients the following AUC were observed: Bindazyme 0.98; EliA 0.95; SPR biosensor 0.93; Farr 0.89; Farrzyme 0.88. Although various methodologies for the determination of anti-dsDNA were compared, the overall diagnostic accuracy was found satisfactory in all immunoassays. Best data were found for the Bindazyme assay. We referenced the measurements to our in-house SPR biosensor device which showed good AUC and DE values. When optimized, this technique, allowing to monitor antigen/ antibody interactions in real-time, may add a new analytical quality to the existing methods, potentially beneficial in diagnosis and clinical monitoring of SLE.

[MR imaging of lymph nodes using Gadofluorine M: feasibility in a swine model at 1.5 and 3T]. / MR-Bildgebung von Lymphknoten mit Gadofluorine M in einem Schweinemodell bei 1,5 and 3T.

PURPOSE: To investigate the potential of Gadofluorine M for targeted lymph node imaging in a human size animal model and on a clinical MR scanner at 1.5 and 3 T. MATERIALS AND METHODS: Pelvic and cervical lymph nodes in a swine model were investigated prior to and 24 hours after intravenous administration of 50 micromol/kg body weight Gadofluorine M, an experimental contrast agent. MR imaging was carried out on clinical 1.5 T and 3 T whole-body MR systems using clinically available coils and T 1-weighted sequences. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) with respect to the surrounding tissue were assessed and compared using the Student's t-test. The Gd concentration in the lymph nodes (n = 43) was measured post mortem by Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). RESULTS: Gadofluorine M allowed for high signal and high contrast visualization of lymph nodes in all stations on post-contrast images with a significantly increased SNR and CNR (SNR pelvic lymph nodes post vs. pre: 46 +/- 7 vs.14 +/- 3, SNR cervical lymph nodes post vs. pre: 105 +/- 64 vs. 32 +/- 21; CNR pelvic lymph node vs. muscle post vs. pre 28 +/- 5 vs. 0.2 +/- 0.5, CNR cervical lymph node vs. muscle post vs. pre 76 +/- 53 vs. 11 +/- 15, p < 0.05 for all comparisons). The SNR and CNR in the pelvis were further improved using 3 T compared to 1.5 T scanners (SNR lymph nodes 3 T vs. 1.5 T 84 +/- 6 vs. 46 +/- 7, CNR lymph node vs. muscle 3 T vs. 1.5 T 53 +/- 9 vs. 28 +/- 5 respectively, p < 0.05). A high concentration of Gd in the lymph nodes was found (149 +/- 25 mmol Gd/L). CONCLUSION: Gadofluorine M accumulates in the lymph nodes and allows for selective targeted high contrast MR imaging of lymph node tissue in a large animal model using clinically available MR imaging techniques. 3 T further improves SNR and CNR compared to 1.5 T.

Increased basal-ganglia activation performing a non-dystonia-related task in focal dystonia.

BACKGROUND AND PURPOSE: We tried to determine whether altered sensorimotor cortex and basal-ganglia activation in blepharospasm (BSP) and cervical dystonia (CD) are restricted to areas directly responsible for the innervation of dystonic muscles, or whether impairment in focal dystonia reaches beyond these direct associations supporting a more global disturbance of sensory and motor control in focal dystonia. METHODS: Twenty patients with focal dystonia (11 BSP, 9 CD) and 14 healthy controls were investigated with functional magnetic resonance imaging (fMRI) performing a simple grip force forearm contraction task. RESULTS: BSP and CD patients and healthy controls showed similar activation in the pre-motor, primary motor and primary sensory cortex, whilst basal-ganglia activation was increased in BSP and CD with related activation patterns compared with controls. BSP patients had increased activation in the thalamus, caudate nucleus, putamen and lateral globus pallidus, whilst CD patients showed increased activation in the caudate nucleus, putamen and thalamus. No differences in applied grip force were detected between groups. CONCLUSIONS: In both, BSP and CD, increased basal-ganglia activation could be demonstrated in a task not primarily involving the dystonic musculature affected by these disorders. Comparable activation changes may also indicate a common pathway in the pathophysiology in BSP and CD.

Patient acceptance of diagnostic laparoscopy.

PURPOSE: To assess patient acceptance of diagnostic conventional laparoscopy and minilaparoscopy under sedoanalgesia. MATERIALS AND METHODS: 120 consecutive patients undergoing diagnostic laparoscopy were enrolled prospectively in this study. Within the first week after diagnostic laparoscopy the patients were asked to answer a total of eight questions with regard to the acceptance of the procedure. RESULTS: The inconvenience of laparoscopy was assessed with a mean of 1.6 on a scale from 0 to 10 (0 = no inconvenience, 10 = very unpleasant). The discomfort in the two days following laparoscopy were graded with a mean of 2.1 on a scale from 0 to 10 (0 = no inconvenience, 10 = very unpleasant). There was no difference between conventional laparoscopy and minilaparoscopy. Only 10% of the patients described laparoscopy more inconvenient in comparison to diagnostic gastroscopy, whereas 29% of the patients assessed diagnostic gastroscopy more inconvenient. CONCLUSIONS: Diagnostic laparoscopy under sedoanalgesia is a very well tolerated procedure. There is no difference between conventional laparoscopy and minilaparoscopy.

[Rare cause of cholestatic hepatitis]. / Seltene Ursache einer cholestatischen Hepatitis.

When bile duct obstruction is ruled out newly developed icterus is mainly caused by infection with hepatotropic viruses, autoimmune hepatitis or drug induced hepatopathy. We report on a 30 year old previously healthy patient with cholestatic hepatitis which was caused by infection with Treponema pallidum. Cholestatic hepatitis resolved after administration of penicillin without recurrence.

[Implementing change--steps toward living environment-oriented support for gerontopsychiatric patients and their caregivers, DGGG Congress, September 2001, Kiel]. / Wandel gestalten--Wege zu lebensweltbezogenen Unterstützungsformen für gerontopsychiatrisch erkrankte Menschen und ihre Angehörigen, DGGG-Tagung, September 2001, Kiel.

The change which is necessary in home and long-term institutional elderly care, first of all, concerns the attitudes, values and norms and the acquisition of key competencies in dealing with people who have a gerontopsychiatric disease. Elderly care and attention of people suffering from dementia therefore requires a principal change in thought. The feeling of well-being is the pre-conditioning and starting point of the caring action, not its result. People suffering from dementia need the feeling of trust and security in order to be able to accept measures which seem to be illogical for them. The adjustment is therefore required from outside by shaping an environment, which provides security and orientation, and by building on caring attention relating to the patients' past interests and history. Participants of the conference could gather information about such innovative approaches in professional elderly care for people suffering from dementia in various workshops, gallery walk and a poster session. All presentations showed an approach, which was oriented towards the living environment and in which questions about the quality and continuity of life were considered to be as important as the aspects of the necessary elderly care. It is not a lack of knowledge about a subject and value oriented care for elderly people suffering from gerontopsychiatric diseases, but rather a deficit in putting this knowledge into practice, as the examples clearly showed. Gerontopsychiatric competencies have to be broadly developed and implemented.

Cone biopsy and pathologic findings at radical hysterectomy in stage I cervical carcinoma.

OBJECTIVE: To examine the association between cone biopsy and pathologic findings at radical hysterectomy in stage I cervical carcinoma. METHODS: Fifty-four patients diagnosed by cone biopsy with stage I cervical carcinoma and treated with radical hysterectomy comprised the study group. The association between the depth of invasion on conization, lymph-vascular invasion, positive cone margins, positive endocervical curettage (ECC), and the depth of residual invasion in the radical hysterectomy specimen was examined using Pearson r and point biserial correlation. Independent predictors of the depth of residual invasion were determined by multiple regression. RESULTS: The depth of residual invasion correlated significantly with the depth of invasion (r =.374) and presence of lymph-vascular invasion (r(pb)=.372) in the conization specimen, post-cone ECC status (r(pb) =.669), and age at diagnosis (r =.347). The same factors were jointly assessed using multiple regression (R(2) =.636, P<.001). Depth of invasion on conization, lymph-vascular invasion, and ECC status were identified as independent predictors of the depth of residual invasion. Patients with deep (5 mm or greater) stromal invasion and lymph-vascular invasion on conization had significantly higher rates of positive parametrial margins (22% compared with zero, P =.001) and adjuvant radiation (66.7% compared with 20%, P =.004) compared with all other patients. CONCLUSION: Depth of invasion, presence of lymph-vascular invasion, and age at diagnosis were independent predictors of the depth of residual invasion in the subsequent hysterectomy specimen. These factors should be considered in treatment planning. Patients with a combination of these factors may have increased risk for deep residual invasion, positive hysterectomy margins, and adjuvant radiation.

Microcystic adnexal carcinoma of the vulva.

BACKGROUND: Microcystic adnexal carcinoma (MAC) is a subset of sweat gland carcinoma first described as a specific entity by D. J. Goldstein, R. J. Barr, and D. J. Santa Cruz (Cancer 1982;50:566-72). We report the first case of MAC occurring on the vulva and review the literature pertaining to this rare tumor. CASE: A 43-year-old multiparous black woman presented initially to Kings County Hospital Medical Center with a chief complaint of a vulvar lesion arising on the left labia majora which she had noted for 4 years prior to presentation. Aside from increasing paresthesia in the area, she denied any constitutional symptoms. Her past medical history was significant only for hyperthyroidism and mild hypertension and surgical history was noncontributory. Gynecologic history was unremarkable, with sporadic care over the last 20 years. Physical examination revealed a 1.5 x 2.0-cm raised, well-circumscribed, firm mobile lesion on the left labia majora. It was noted to be yellow in color with the surrounding tissue being unremarkable in character. The remainder of her gynecologic examination and lymph node survey was unremarkable. Preoperative chest X ray was negative as was the CAT scan of the abdomen and pelvis. All laboratory values were within normal limits. A Pap smear done preoperatively was significant for atypical squamous and glandular cells of undetermined significance. Subsequent colposcopic examination of the cervix was remarkable for cervicitis and was adequate, with the entire transformation zone visualized. Both endocervical curettage and endometrial biopsy were normal. Initially, an excisional biopsy was performed with final pathology demonstrating microcystic adnexal carcinoma with positive surgical margins. She subsequently underwent a left radical hemivulvectomy with bilateral inguinal groin lymph node dissection. At the time of surgery, the left labia majora was noted to be well healed, with a residual surgical scar easily discernible. No areas of discoloration were noted and digital palpation of the area was unremarkable. Microscopic residual tumor was noted; however, all surgical margins and lymph nodes were negative for tumor. Her postoperative course was unremarkable. The patient has continued to do well since the time of her surgery and is being followed conservatively. CONCLUSION: Radical vulvectomy should be performed when MAC occurs in the vulva to secure negative margins of resection. Groin dissection should be reserved for cases in which the inguinal lymph nodes are clinically suspicious or in cases of tumor recurrence.

Magnetic resonance imaging in the preoperative determination of tumor resectability in previously irradiated groin tumor.

We present an unusual case in which magnetic resonance (MR) imaging was utilized in the preoperative determination of resectability of a large inguinal tumor. The patient had previously presented with a large fungating, surgically nonresectable mass, which impinged upon the anterior ramus of the pubic bone. Following chemotherapy and radiation, the mass appeared more mobile and surgically resectable. Due to fibrosis and induration, the relationship of the tumor and underlying femoral vascular bundle were unclear. MR imaging clearly depicted that the tumor was sufficiently distant from the vessels, to allow safe resection with an adequate surgical margin. Resection was performed with clear lateral and deep margins. Histopathology demonstrated squamous cell carcinoma of the inguinal skin replacing subcutaneous tissue.

Endogenous brain cytokine mRNA and inflammatory responses to lipopolysaccharide are elevated in the Tg2576 transgenic mouse model of Alzheimer's disease.

Beta-amyloid (Abeta) plaques have been shown to induce inflammatory changes in Alzheimer's disease brains. Cortical, but not cerebellar tissue from 16-month-old Tg2576 (Tg+) mice showed significant increases in interleukin (IL)-1alpha (2.2-fold), IL-1beta (3.4-fold), tumor necrosis factor-alpha (3.9-fold), and monocyte chemoattractant protein-1 (2.5-fold) mRNA levels compared to controls (Tg-). These changes were not apparent in 6-month-old Tg+ mice except for TNF-alpha. mRNA levels of glial fibrillary acidic protein and complement components, C1qA and C3 were also elevated in aged mice. Lipopolysaccharide (LPS) (25 microg/mouse, i.v.) induced a significantly greater production of IL-1beta protein in the cortices and hippocampi of Tg+ vs. Tg- mice at 1, 2, 4, and 6 h. Experiments in 6-month-old mice showed that not only was there less cytokine produced compared to 16-month-old mice, but the exacerbated cytokine response to LPS in Tg+ mice was not apparent. Higher levels of Abeta1-40 were measured in the cortices of 6- and 16-month-old Tg+ mice at 4-6 h after LPS, which returned to baseline after 18 h. We demonstrate that Abeta plaques elicit inflammatory responses in Tg2576 mice that are further exacerbated when challenged by an exogenous inflammatory insult, which may serve to amplify degenerative processes.

Computed tomography guided core needle biopsy diagnosis of pelvic actinomycosis.

BACKGROUND: Pelvic actinomycosis is a chronic suppurative inflammatory disease caused by the anaerobic Gram-positive bacilli Actinomyces israelii. The propensity of this disease to simulate gynecological malignancies has been described previously. The great majority of these patients were diagnosed with actinomycotic diseases during or after exploratory laparotomy, but rarely preoperatively. We reviewed the literature pertaining the management of pelvic actinomycosis. CASE: A nulliparous woman with a long history of intrauterine contraceptive device (IUD) and recent Papanicolaou smear findings consistent with the presence of actinomyces presented with chronic vague lower abdominal pain, weight loss, poor appetite, and recent increase in abdominal girth associated with a large immobile pelvic mass. Transcutaneous computed tomography guided core needle biopsy established the diagnosis of pelvic actinomycosis obviating immediate surgical intervention. Intravenous and subsequent long-term oral penicillin therapy was constituted and resulted in a significant decrease in the size of the pelvic mass. CONCLUSION: In patients presenting with pelvic masses and a history of IUD placement, actinomycotic infection should be considered and diagnosis attempted by imaging guided needle biopsy. Furthermore, this case suggested that correct nonsurgical diagnosis of pelvic actinomycosis followed by prolonged antibiotic therapy might eliminate the need for extensive extirpative surgery and assist in maintaining future fertility.

B-cell antigen receptor competence regulates B-lymphocyte selection and survival.

Experimental evidence contradicts the simplistic view that during development all B cells expressing non autoreactive antigen receptors on the cell surface are selected into the mature B-cell pool. While allelic exclusion, clonal selection and affinity maturation continue to define the mainstream notions of B-cell development and selection, new evidence is redefining our understanding of these processes. Receptor editing replaces functional B-cell receptors by secondary immunoglobulin gene rearrangements, a process that can play roles in both immune tolerance and immune response. In addition, editing can rescue cells that would otherwise fail positive selection. We focus here on our studies indicating that the functional competence of the B-cell antigen receptor complex plays a central role in the fate of developing B cells and their antigen receptor genes.

Rapid progression of primary vaginal squamous cell carcinoma in a young HIV-infected woman.

BACKGROUND: The association of human immunodeficiency virus (HIV) infection with rapid progression of cervical and anal squamous cell carcinoma has been clearly established by several studies. Human papilloma virus (HPV) infection of the anogenital tract is believed to be the causative agent of cervical, anal, vaginal, and vulvar squamous cell carcinoma. While a myriad of reports exist in the literature pertaining to the rapid progression of cervical and anal carcinoma in HIV-infected patients, no association of HIV infection and vaginal carcinoma has been reported. We present an unusual case of a young woman infected with HIV who was diagnosed with advanced vaginal carcinoma and succumbed to her disease shortly thereafter despite aggressive treatment. CASE: A 40-year-old woman with a 2-year history of HIV infection presented with Stage IVA squamous cell carcinoma of the vagina and a large vesicovaginal fistula from the tumor eroding through the posterior bladder wall. Computed tomography (CT) of the abdomen and pelvis revealed a large tumor replacing the vagina with mild hydronephrosis and diffuse pelvic and inguinal lymphadenopathy. She underwent urinary diversion with a transverse colon conduit followed by pelvic radiation with weekly cisplatin chemosensitization. A repeat CT scan of the abdomen and pelvis upon completion of her treatment revealed progression of disease with multiple liver metastases and gastrohepatic ligament adenopathy. She subsequently died of advanced metastatic vaginal carcinoma 2 months after completion of treatment. CONCLUSION: Due to the rarity of primary vaginal carcinoma, the clinical behavior of this neoplasm in the HIV-infected patient is poorly understood. Our case indicates that, although vaginal carcinoma is a disease of the elderly, young women infected with HIV and HPV are predisposed not only to develop cervical or anal carcinoma but also may be at increased risk for vaginal carcinoma with more aggressive and less responsive disease. Furthermore, although vaginal carcinoma is usually a slow-growing neoplasm, this case illustrates the aggressive behavior of such a tumor when associated with HIV infection.

Membrane-anchored aspartyl protease with Alzheimer's disease beta-secretase activity.

Mutations in the gene encoding the amyloid protein precursor (APP) cause autosomal dominant Alzheimer's disease. Cleavage of APP by unidentified proteases, referred to as beta- and gamma-secretases, generates the amyloid beta-peptide, the main component of the amyloid plaques found in Alzheimer's disease patients. The disease-causing mutations flank the protease cleavage sites in APP and facilitate its cleavage. Here we identify a new membrane-bound aspartyl protease (Asp2) with beta-secretase activity. The Asp2 gene is expressed widely in brain and other tissues. Decreasing the expression of Asp2 in cells reduces amyloid beta-peptide production and blocks the accumulation of the carboxy-terminal APP fragment that is created by beta-secretase cleavage. Solubilized Asp2 protein cleaves a synthetic APP peptide substrate at the beta-secretase site, and the rate of cleavage is increased tenfold by a mutation associated with early-onset Alzheimer's disease in Sweden. Thus, Asp2 is a new protein target for drugs that are designed to block the production of amyloid beta-peptide peptide and the consequent formation of amyloid plaque in Alzheimer's disease.

The significance of ASCUS cytology in HIV-positive women.

OBJECTIVE: The aim of this study was to determine the incidence and severity of dysplasia associated with a cytologic diagnosis of atypical cells of undetermined significance (ASCUS) in women infected with the human immunodeficiency virus (HIV). METHODS: A cross-sectional analysis of cervical cytology, colposcopic impression, and cervical biopsy results was performed on 261 HIV-positive women diagnosed with ASCUS. The prevalence and grade of histologically documented cervical intraepithelial neoplasia (CIN) was determined. Patients with CD4 counts above and below 200 cells/mm(3) were compared using chi(2) analysis to determine any effect of worsening immunosuppression on the rates of associated dysplasia. RESULTS: Seven hundred sixty-one Pap smears were performed during the study period. Two hundred nine (27%) were diagnosed as ASCUS. All patients (pts) received colposcopic evaluation. The incidence of human papilloma virus (HPV) effect, low-grade CIN (I), and high-grade CIN (II, III, and carcinoma in situ) documented by cervical biopsy, cervical conization or endocervical curettings was 40, 17, and 15%, respectively. No cases of invasive cancer were found. These results are similar to those of previous cytohistologic studies of ASCUS in HIV-untested populations. There was no significant difference in frequency or severity of CIN in pts with severe immunosuppression (P = 0.4). CONCLUSION: A cytologic diagnosis of ASCUS in HIV-positive women identifies a group at significant risk for histologic abnormalities. The majority of pts will be diagnosed with HPV or low-grade CIN. HIV infection and severe immunosuppression do not appear to increase the frequency or severity of CIN associated with ASCUS. Given the 32% risk of associated CIN, all HIV-positive women with ASCUS cytology should undergo colposcopic evaluation.