Caudate blood flow and volume are reduced in HIV+ neurocognitively impaired patients

OBJECTIVE

To evaluate the effects of HIV-associated neurocognitive impairment on caudate blood flow and volume.

METHODS

The authors performed continuous arterial spin labeled MRI on 42 HIV+ patients (23 subsyndromic and 19 HIV neurosymptomatic) on highly active antiretroviral therapy and 17 seronegative controls. They compared caudate blood flow and volume among groups.

RESULTS

A stepwise decrease in both caudate blood flow and volume was observed with increasing HIV-associated neurocognitive impairment. Compared with seronegative controls, baseline caudate blood flow was reduced in HIV+ neurosymptomatic patients (p = 0.001) with a similar decreasing trend for subsyndromic HIV+ patients (p = 0.070). Differences in caudate volume were observed only for neurosymptomatic HIV+ patients compared with controls (p = 0.010). A Jonckheere-Terpstra test for trends was significant for both caudate blood flow and volume for each of the three subgroups. Pearson product moment correlation coefficients were not significant between caudate blood flow and volume for each group.

CONCLUSIONS

Decreasing trends in caudate blood flow and volume were associated with significantly increasing HIV-associated neurocognitive impairment (HNCI), with the greatest decreases observed for more severely impaired patients. However, reductions in caudate blood flow and volume were poorly correlated. Changes in residual caudate blood flow may act as a surrogate biomarker for classifying the degree of HNCI.

Efficacy and tolerability of the new antiepileptic drugs I: treatment of new onset epilepsy: report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide-reviewed in the order in which these agents received approval by the US Food and Drug Administration) in the treatment of children and adults with newly diagnosed partial and generalized epilepsies.

METHODS

A 23-member committee, including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy, evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until September 2002, with selected manual searches up until 2003.

RESULTS

There is evidence either from comparative or dose-controlled trials that gabapentin, lamotrigine, topiramate, and oxcarbazepine have efficacy as monotherapy in newly diagnosed adolescents and adults with either partial or mixed seizure disorders. There is also evidence that lamotrigine is effective for newly diagnosed absence seizures in children. Evidence for effectiveness of the new AEDs in newly diagnosed patients with other generalized epilepsy syndromes is lacking.

CONCLUSIONS

The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with newly diagnosed epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Efficacy and tolerability of the new antiepileptic drugs II: Treatment of refractory epilepsy: Report of the Therapeutics and Technology Assessment Subcommittee and Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society

OBJECTIVE

To assess the evidence demonstrating efficacy, tolerability, and safety of seven new antiepileptic drugs (AEDs) (gabapentin, lamotrigine, topiramate, tiagabine, oxcarbazepine, levetiracetam, and zonisamide) in the treatment of children and adults with refractory partial and generalized epilepsies.

METHODS

A 23-member committee including general neurologists, pediatric neurologists, epileptologists, and doctors in pharmacy evaluated the available evidence based on a structured literature review including MEDLINE, Current Contents, and Cochrane library for relevant articles from 1987 until March 2003.

RESULTS

All of the new AEDs were found to be appropriate for adjunctive treatment of refractory partial seizures in adults. Gabapentin can be effective for the treatment of mixed seizure disorders, and gabapentin, lamotrigine, oxcarbazepine, and topiramate for the treatment of refractory partial seizures in children. Limited evidence suggests that lamotrigine and topiramate are also effective for adjunctive treatment of idiopathic generalized epilepsy in adults and children, as well as treatment of the Lennox Gastaut syndrome.

CONCLUSIONS

The choice of AED depends upon seizure and/or syndrome type, patient age, concomitant medications, AED tolerability, safety, and efficacy. The results of this evidence-based assessment provide guidelines for the prescription of AEDs for patients with refractory epilepsy and identify those seizure types and syndromes where more evidence is necessary.

Changes in glucocorticoid and mineralocorticoid hormone levels due to compensation for ileostomy losses

BACKGROUND

The Ileo-Pouch-Anal-Anastomosis (IPAA) is the standard restorative procedure for Ulcerative Colitis and Familial Adenomatous Polyposis (FAP). IPAA may lead to considerable losses of fluids, especially in association with a protective loop ileostomy.

AIM

The aim of this study was to investigate adrenal mechanisms in the regulation of volume homeostasis immediately after IPAA and protective ileostomy.

METHODS

For that purpose, 20 patients out of our patient population with elective IPAA with ileostomy participated in this study between 1993 and 1997. In all patients, routine laboratory tests and gluco- and minealocorticoid hormone measurements were performed preoperatively and 10 days after operation.

RESULTS

These blood analyses indicated functional hyperaldosteronism immediately after IPAA. Significantly elevated levels of Aldosterone (36.4 +/- 25.1 ng/dl) and 18-OH-Corticosterone ( 173 +/- 11.3 ng/dl) were found. Among hormones with glucocorticoid effects, blood levels of Cortisol (10.4 +/- 4.8 microg/dl) were significantly elevated, while 11-Desoxycortiosterone (13.9 +/- 8.4 ng/dl) and Corticosterone (0.8 +/- 0.6 microg/dl) were not significantly elevated. Serum electrolytes remained unchanged.

CONCLUSIONS

Our results indicate that hormones with mineralocorticoid effects play a predominant role in the compensation of ileostomy losses after IPAA.

Glutamine distribution in patients with ulcerative colitis and in patients with familial adenomatous polyposis coli before and after restorative proctocolectomy

BACKGROUND AND AIMS

Restorative proctocolectomy with construction of an ileoanal pouch (IPAA) is the surgical treatment of choice for patients with ulcerative colitis (UC) or familial adenomatous polyposis (FAP). This procedure imposes an essential change in function on the terminal ileal mucosa and pouch mucosa. Glutamine is one of the major nutrients for the small-bowel mucosa; it is metabolized into glutamate and subsequently alanine in the human enterocyte. In a prospective clinical trial we compared glutamine distribution in patients with UC to that in patients with FAP before and after restorative proctocolectomy.

METHODS AND PATIENTS

Concentrations of glutamine, glutamate, and alanine were measured pre- and postoperatively in the terminal ileal mucosa, pouch mucosa, skeletal muscle and venous blood of patients undergoing IPAA for UC or FAP. Healthy individuals served as controls for skeletal muscle glutamine concentration.

RESULTS

After IPAA the glutamine concentration in UC patients was decreased in skeletal muscle. In the mucosa glutamine remained unaltered while glutamate and alanine concentrations increased. In plasma the glutamine concentration increased, the glutamate level fell, and the alanine level increased. In FAP patients the glutamine level was unchanged in skeletal muscle after IPAA. In mucosa the glutamine level did not change, but glutamate and alanine increased. In plasma the glutamine level remained unaltered, glutamate decreased, and alanine increased.

CONCLUSION

Patients with UC or FAP before surgical therapy do not suffer from glutamine depletion. IPAA resulted in changes in the distribution of glutamine and its metabolites in skeletal muscle, plasma, and ileal pouch mucosa, particularly in patients with UC. Further studies should investigate whether characteristics in the glutamine distribution have any impact for the long-term outcome after IPAA.

[The ileo-anal pouch procedure: Complications, quality of life, and long-term results]

The ileo-anal pouch procedure: Complications, quality of life, and long-term results. Restorative proctocolectomy with construction of an ileal pouch-anal anastomosis (IPAA) has evolved as the surgical therapy of choice for patients with ulcerative colitis (UC) and patients with familial adenomatous polyposis (FAP). 662 patients (493 UC, 169 FAP) consecutively received IPAA. Marked differences were observed between UC and FAP patients regarding the rates of overall complications (33.1 % vs. 12.5 %), pouchitis (29 % vs. 2 %), and pouch extirpation (3.2 % vs. 0.6 %). Pouchitis occurred as primary (79 %) and secundary (21 %) form, with acute (67.2 %) or chronic (32.8 %) course. Each form and course required specific therapy. Chronic pouchitis implies the risk of malignant transformation of the pouch mucosa. Quality of life improves significantly after IPAA in patients with UC and is equal to that in normal individuals, in UC and FAP, if postoperative complications are either prevented or under control.

[Photodynamic therapy in the gastrointestinal tract. Possibilities and limits]

BACKGROUND

Photodynamic therapy (PDT) is characterized by the extensive selective accumulation of a photoactive agent, the photosensitizer, in malignant or precancerous tumour cells. The photoactive compound is activated by light beam of a specific wavelength and causes cell death. A significant proportion of patients with gastrointestinal malignancies cannot undergo curative treatment, as either the cancer is too advanced or the patient's general constitution is too poor to allow invasive strategies. In such cases, PDT has already proven to be a promising therapeutic modality for selected dysplasias and malignancies in the gastrointestinal tract.

MATERIAL AND METHODS

A retrospective review of the literature was performed in order to determine the experience gained with PDT and to assess its clinical value in the curative and palliative management of gastrointestinal neoplasms.

RESULTS

PDT seems to be an adequate treatment for selected forms of early cancer and small lesions of the GI tract or for small residual areas after the tumour has been debulked by other techniques (e.g. limited surgical resection, thermal ablation). Especially for patients who refuse or are ineligible for conventional surgery, PDT offers promising results compared to currently accepted clinical approaches.

CONCLUSIONS

As a primary or adjuvant mode for either curative or palliative treatment of gastrointestinal neoplasms, PDT is a potentially effective, minimally invasive therapeutic modality. However, further clinical assessment by means of comparative, standardized studies is essential to the definition of its role in oncology.

["High pouch output" syndrome. Role of mineralocorticoid diagnosis after restorative proctocolectomy]

The two-phase restorative proctocolectomy is the treatment of choice for surgical therapy of the familial adenomatous polyposis (FAP) and also for the ulcerative colitis (UC). Besides the well-known complications the entire removal of the colorectum leads to an impairment of fluid and electrolyte resorption.

PATIENTS AND METHODS

Over a time period of two years we observed 320 proctocolectomized patients with ileal pouch-anal anastomosis (IPAA). All patients with high pouch output but without organic malfunction were identified. The organic reasons were excluded with the help of pouchoscopy, radiography or MR imaging. We evaluated routine parameters, the kidney function, the electrolyte changes, the acid-base balance and the urine pH, as well as the hormonal changes of the suprarenal glands. We identified seven patients with 'high pouch output' out of 320 patients observed. The control group consisted of 14 proctocolectomized patients without hints of complications in the endoscopic, radiographic and routine laboratory diagnostics.

RESULTS

Neither group showed any significant differences in the analysis of the routine parameters. A significant drop of the urine sodium concentration of 40.5 +/- 18.7 mmol/l (control group 98 +/- 43.4 mmol/l) was observed in the group with 'high pouch output'. In this group the plasma aldosterone values were strongly increased with an average of 42.6 +/- 28.9 ng/dl (control group 13.2 +/- 6.8 ng/dl) as well as the plasma 18-hydroxycorticosterone with an average of 153.7 +/- 121.1 ng/dl (control group 153.7 +/- 121.1 ng/dl). Neither group of patients showed increased activity of free corticosterone and free cortisol. Only free 11-desoxycorticosterone was elevated in the group with 'high pouch output'.

CONCLUSION

Our results prove that the mineralocorticoid adrenal activity plays a central role in order to preserve the volume and electrolyte homeostasis. The low frequency of 'high-pouch-output'-complications in realms of the restorative proctocolectomy proves the excellent compensation of the removal of the colon mucosa. Plasma aldosterone seems to be a diagnostic marker encapsulating the reabsorption problems of intestinal salt and volume losses after proctocolectomy.

Result of two randomized trials comparing nolatrexed (Thymitaq) versus methotrexate in patients with recurrent head and neck cancer

We report on two randomized trials performed in the USA and Europe, which compared methotrexate and nolatrexed as treatment for patients with recurrent head and neck cancer. Eligibility criteria included: histologically confirmed squamous-cell carcinoma, measurable disease, adequate hematological, renal and hepatic functions, failure of a first-line chemotherapy, and informed consent. Methotrexate 40 mg/m2 was weekly given by short infusion, and nolatrexed 725 mg/m2 per day was administered as a five-day continuous infusion, every three weeks. A total of 139 patients (63 in the USA. 76 in Europe) were randomized based on a ratio of 2/1: 93 and 46 received nolatrexed and methotrexate, respectively. Patient characteristics included 115 males and 24 females; median age 60 years. In the nolatrexed arm, the following grade 3-4 toxicities occurred: neutropenia (29.9%) with 3.1% of febrile neutropenia, mucositis (33.3%), and vomiting (10.3%). In the MTX arm, the grade 3-4 toxicities were neutropenia (7.1%) and mucositis (6.9%). There was no difference in activity between the nolatrexed and the methotrexate treatment: 3.3% and 10.8% of objective responses, 1.9 versus 1.5 months of disease-free progression and 3.5 versus 3.7 months of overall survival, respectively. Nolatrexed has demonstrated a similar activity to methotrexate.

Modeling of chaotic vibrations in symmetric vocal folds

The chaos mechanism of above-range phonation was examined in symmetrically modeled vocal folds by using the traditional two-mass model assumption. The Poincaré map technique was used to display chaotic attractors. This method provided an effective description of irregular vocal-fold movements. The power spectrum, Lyapunov exponent, and Kaplan-Yorke dimension were employed to describe chaotic vibrations in the vocal-fold model. These nonlinear dynamic analyses suggested that, for the positive Lyapunov exponent, chaotic attractors contribute to irregular vocal-fold vibrations. Descriptions of complicated irregular vibrations of the vocal fold yielded evidence of chaos. To investigate the effects of independent parameters such as subglottal pressure, coupling stiffness, and phonation neutral area, bifurcation diagrams based on the Poincaré map were discussed. The results confirmed that the dynamics of the two-mass model was strongly influenced by independent parameters. Nonlinear dynamic methods were expected to provide useful information for better understanding of irregular vocal-fold vibrations as well as of the dynamic mechanism of above-range phonation in excised larynx experimentation.

Association of decreased perfusion of the ileoanal pouch mucosa with early postoperative pouchitis and local septic complications

BACKGROUND

After ileoanal pouch operation, 5% to 40% of patients with ulcerative colitis and 2% to 8% of patients with familial adenomatous polyposis develop pouchitis. Seven percent to 32% of all patients have local septic complications. Pouch ischemia is discussed as a pathophysiologic factor. Tonometry is a minimally invasive method for estimating intramucosal pH (pHi), with a decreased pHi showing intramucosal acidosis characteristic of hypoperfusion.

HYPOTHESIS

Decreased perfusion of the iloanal pouch measured by pHi is associated with local septic complications and the development of pouchitis.

DESIGN

Prospective cohort study.

SETTING

Surgical department of a university hospital.

PATIENTS AND METHODS

The pHi in the ileoanal pouch of 98 patients was measured directly after the pouch procedure and correlated to the clinical course. Endoscopic examination of the pouch with biopsy and blinded histologic assessment, including calculation of a histologic pouchitis score, were routinely performed 3 months postoperatively.

MAIN OUTCOME MEASURES

Development of pouchitis and local septic complications in correlation to pHi.

RESULTS

A decreased pHi was statistically significantly associated with the development of pouchitis and the rate of local septic complications. All 3 patients with anastomotic stenosis had a pHi less than 7.00. The diagnosis of ulcerative colitis just failed in statistical significance as a risk factor for pouchitis. An increased body mass index just failed as a statistically significant risk factor for complications but was a risk factor for the development of acute pouchitis.

CONCLUSION

Pouch hypoperfusion is a risk factor for the development of pouchitis and local septic complications.

Eta(') mass and chiral symmetry breaking at large N(c) and N(f)

We propose a method for implementing the large- N(c), large-N(f) limit of QCD at the effective Lagrangian level. Depending on the value of the ratio N(f)/N(c), different patterns of chiral symmetry breaking can arise, leading in particular to different behaviors of the eta(') mass in the combined large-N limit.

Human immunodeficiency virus type 1-infected persons with residual disease and virus reservoirs on suppressive highly active antiretroviral therapy can be stratified into relevant virologic and immunologic subgroups

A significant percentage of human immunodeficiency virus type 1 (HIV-1)-infected persons treated with highly active antiretroviral therapy (HAART) will develop plasma HIV-1-specific virion RNA levels <50 copies/mL. HIV-1-infected persons receiving virally suppressive HAART were studied with a viral outgrowth assay of the patients' peripheral blood mononuclear cells (PBMC), and a quantitative polymerase chain reaction assay was used to analyze HIV-1 2-long terminal repeat (2-LTR) circular DNA in PBMC, which indicates new HIV-1 infections of cells in vivo. Viral outgrowth in vitro correlated inversely with the level of peripheral blood CD4(+) T lymphocytes. Detection and quantitation of 2-LTR circular DNA correlated strongly with viral outgrowth patterns and inversely with CD4(+) T lymphocyte counts. Relevant subgroups of HIV-1-infected subjects on suppressive HAART with residual viral disease and reservoirs can now be stratified.

Long-term follow-up after ileoanal pouch procedure: algorithm for diagnosis, classification, and management of pouchitis

PURPOSE

Inflammation of the ileoanal pouch (pouchitis) is one of the main complications after restorative proctocolectomy, yet its cause remains poorly understood. A standardized definition and diagnostic procedures in pouchitis are lacking.

METHOD

We analyzed all cases of pouchitis occurring in a group of 308 patients (210 with ulcerative colitis, 98 with familial adenomatous polyposis) who took part in a prospective long-term follow-up program. The severity of pouchitis was measured using a pouchitis activity score (Heidelberg Pouchitis Activity Score). An algorithm for the classification and management of pouchitis was established which enables the clinician: 1) to determine the severity of pouchitis, 2) to differentiate between primary pouchitis and pouchitis caused by surgical complications (secondary pouchitis), and 3) to evaluate the course (acute vs. chronic (> 3 months)).

RESULTS

The median duration of follow-up was 48 (range, 13-119) months. At least one episode of pouchitis was diagnosed in 29 percent of patients with ulcerative colitis and in 2 percent of familial adenomatous polyposis patients. Secondary pouchitis occurred in 6 percent of ulcerative colitis patients and was cured by surgical treatment in 13 (87 percent) of 15 cases. Primary pouchitis was diagnosed in 23 percent of ulcerative colitis patients, including 6 percent of all ulcerative colitis patients with chronic primary pouchitis. The latter showed poor response to medical treatment. In one case multifocal high-grade dysplasia occurred. Histologic examination of the excised pouch identified a carcinoma originating from the ileal mucosa.

CONCLUSIONS

Ulcerative colitis patients after restorative proctocolectomy face a high risk of developing pouchitis. The algorithm used in this study was highly efficient in identifying patients with a secondary pouchitis who require surgical treatment and patients with chronic primary pouchitis. For the latter, long-term surveillance seems mandatory because of the risk of malignant transformation of the pouch mucosa.

Backwash ileitis is strongly associated with colorectal carcinoma in ulcerative colitis

BACKGROUND & AIMS

Commonly accepted risk factors for colorectal carcinoma (CRC) in ulcerative colitis are duration and extent of disease. By identifying still unknown risk factors, surveillance strategies may be improved further. We investigated whether backwash ileitis is also a factor associated with CRC in ulcerative colitis.

METHODS

Five hundred ninety consecutive patients with ulcerative colitis who received restorative proctocolectomy were classified into 3 groups: (1) pancolitis with backwash ileitis, (2) pancolitis without backwash ileitis, and (3) left-sided colitis. The association with CRC was analyzed in these 3 groups of patients. As further risk factors, we investigated disease duration, dysplasia, primary sclerosing cholangitis, age at diagnosis of disease, disease activity, and gender. Univariate and multivariate logistic regression were used for analysis.

RESULTS

CRC was diagnosed in 11.2% of all patients. CRC was found in 29.0% of 107 patients in group 1, compared with 9.0% of 369 patients in group 2, and in 1.8% of 114 patients in group 3 (P < 0.001). Cancer patients in group 1 showed significantly more multiple tumor growth (45.2%) than patients in group 2 (24.2%) and group 3 (0%) (P = 0.041). Estimating the relative risk for CRC in the multivariate analysis, patients in group 1 showed a significantly higher odds ratio than patients in groups 2 and 3 (odds ratio: 19.36 vs. 9.58 vs. 1; P < 0.001). High-grade dysplasia, low-grade dysplasia, disease duration of more than 10 years, and disease duration of less than 10 years in patients older than 45 years were further factors with significantly increased risk (odds ratios: 21.69, 6.36, 3.63, 4.37), but primary sclerosing cholangitis was not (P = 0.080). However, primary sclerosing cholangitis was strongly associated with backwash ileitis.

CONCLUSIONS

There is a strong association of backwash ileitis with CRC in patients with ulcerative colitis who undergo proctocolectomy. The predictive value of backwash ileitis for CRC and premalignant dysplasia in patients with ulcerative colitis should be investigated in future studies based on colonoscopic surveillance.

Antibody to transforming growth factor-beta ameliorates tubular apoptosis in unilateral ureteral obstruction

BACKGROUND

Unilateral ureteral obstruction (UUO) is characterized by progressive renal atrophy, renal interstitial fibrosis, an increase in renal transforming growth factor-beta (TGF-beta), and renal tubular apoptosis. The present study was undertaken to determine the effect of a monoclonal antibody to TGF-beta (1D11) in UUO.

METHODS

Mechanical stretch was applied to tubular epithelial cells (NRK-52E) by a computer-assisted system. Three doses of 1D11 (either 0.5, 2, or 4 mg/rat) were administered to rats one day prior to UUO and every two days thereafter, and kidneys were harvested at day 13. Fibrosis was assessed by measuring tissue hydroxyproline and mRNA for collagen and fibronectin. Apoptosis was assessed with the terminal deoxy transferase uridine triphosphate nick end-labeling assay. TGF-beta levels were determined by bioassay. Western blot and immunostaining were used to identify proliferating cell nuclear antigen (PCNA), p53, bcl-2, and inducible nitric oxide synthase (iNOS).

RESULTS

Stretch significantly induced apoptosis in NRK-52E cells, which was accompanied by an increased release of TGF-beta; 1D11 (10 microg/mL) totally inhibited stretch-induced apoptosis. Control obstructed kidney contained 20-fold higher TGF-beta as compared with its unobstructed kidney; 1D11 neutralized tissue TGF-beta of the obstructed kidney. Control obstructed kidney exhibited significantly more fibrosis and tubular apoptosis than its unobstructed counterpart, which was blunted by 1D11. In contrast, 1D11 significantly increased tubular proliferation. p53 immunostaining was localized to renal tubular nuclei of control obstructed kidney and was diminished by 1D11. In contrast, bcl-2 was up-regulated in the 1D11-treated obstructed kidney. Total NOS activity and iNOS activity of the obstructed kidney were increased by 1D11 treatment.

CONCLUSION

The present study strongly suggests that an antibody to TGF-beta is a promising agent to prevent renal tubular fibrosis and apoptosis in UUO.

Interstitial fibrosis of unilateral ureteral obstruction is exacerbated in kidneys of mice lacking the gene for inducible nitric oxide synthase

Unilateral ureteral obstruction (UUO) is characterized by decreases in renal function and increases in interstitial fibrosis. Previous studies have indicated that pharmacologic manipulations that increase nitric oxide (NO) are beneficial to the obstructed kidneys. NO is produced from arginine by nitric oxide synthase (NOS), an enzyme that exists in both constitutive and inducible (iNOS) forms. To determine the role of the inducible form of NOS in UUO, we used mice with a targeted deletion of iNOS (iNOS -/- mice) and compared them with wild-type (WT) mice. Kidneys were obstructed for 2 weeks in both WT and iNOS -/- mice, and were then removed and bisected. Half of the kidney was embedded in paraffin and tissue sections were examined for interstitial volume or the presence of macrophages. The remainder was flash-frozen and samples were used to measure tissue collagen (hydroxyproline) or transforming growth factor-beta (TGF-beta). This study demonstrates that both cortex and medulla of obstructed kidneys of iNOS -/- mice exhibit significantly increased interstitial volume and interstitial macrophages as compared with their WT counterparts. Furthermore tissue collagen was increased to 9.2+/-1.3 microg/mg tissue in WT obstructed kidneys, whereas in iNOS -/- kidneys, collagen was increased to 13.2+/-0.8 microg/mg tissue. The profibrotic cytokine TGF-beta was also significantly increased in obstructed kidneys of iNOS -/- mice, as compared with WT mice. No differences were noted between the unobstructed kidneys of iNOS -/- mice compared with WT mice in any of the parameters examined. These results demonstrate that targeted deletion of the iNOS results in exacerbation of fibrotic events in the obstructed kidney. These results confirm previous pharmacologic studies, and suggest that NO produced via the inducible NOS normally serves a protective function in UUO.