Intra-renal and subcellular distribution of the human chloride channel, CLC-5, reveals a pathophysiological basis for Dent's disease

Dent's disease, which is a renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is associated with inactivating mutations of the X-linked chloride channel, CLC-5. However, the manner in which a functional loss of CLC-5 leads to such diverse renal abnormalities remains to be defined. In order to elucidate this, we performed studies to determine the segmental expression of CLC-5 in the human kidney and to define its intracellular distribution. We raised and characterized antisera against human CLC-5, and identified by immunoblotting an 83 kDa band corresponding to CLC-5 in human kidney cortex and medulla. Immunohistochemistry revealed CLC-5 expression in the epithelial cells lining the proximal tubules and the thick ascending limbs of Henle's loop, and in intercalated cells of the collecting ducts. Studies of subcellular human kidney fractions established that CLC-5 distribution was associated best with that of Rab4, which is a marker of recycling early endosomes. In addition, confocal microscopy studies using the proximal tubular cell model of opossum kidney cells, which endogenously expressed CLC-5, revealed that CLC-5 co-localized with the albumin-containing endocytic vesicles that form part of the receptor-mediated endocytic pathway. Thus, CLC-5 is expressed at multiple sites in the human nephron and is likely to have a role in the receptor-mediated endocytic pathway. Furthermore, the functional loss of CLC-5 in the proximal tubules and the thick ascending limbs provides an explanation for the occurrences of low molecular weight proteinuria and hypercalciuria, respectively. These results help to elucidate further the patho-physiological basis of the renal tubular defects of Dent's disease.     

KinMutBase, a database of human disease-causing protein kinase mutations

KinMutBase (http://www.uta.fi/laitokset/imt/KinMut Base.html) is a registry of mutations in human protein kinases related to disorders. Kinases are essential cellular signalling molecules, in which mutations can lead into diseases including, e.g., immunodeficiencies, cancers and endocrine disorders. The first release of KinMutBase contains information for nine protein tyrosine kinases. There are altogether 170 entries representing 273 families and 403 patients. Mutations appear both in conserved hallmark residues of the kinases as well as in non-homologous sites. The KinMutBase WWW pages provide plenty of information, namely mutation statistics and display, clickable sequences with mutations, restriction enzyme patterns and online submission.     

Stable association of PYK2 and p130(Cas) in osteoclasts and their co-localization in the sealing zone

Bone resorption is initiated by osteoclast attachment to the mineralized matrix, cytoskeletal reorganization, cellular polarization, and the formation of the sealing zone. The present study examines the interaction between PYK2 and p130(Cas) (Crk-associated substrate), suggested to be part of the signaling pathway initiated by osteoclast adhesion. Using murine osteoclast-like cells (OCLs) and their mononuclear precursors (pOCs), generated in a co-culture of bone marrow and osteoblastic MB1.8 cells, we show that: 1) p130(Cas) is tyrosine-phosphorylated upon adhesion of pOCs to vitronectin or ligation of beta3 integrins; 2) p130(Cas) colocalizes with PYK2 and the cytoskeletal proteins F-actin, vinculin, and paxillin in the podosomal-rich ring-like structures of OCLs plated on glass and in the sealing zone in actively resorbing OCLs on bone; 3) p130(Cas) and PYK2 form a stable complex in pOCs, independent of tyrosine phosphorylation of either molecule, and this complex is present in Src (-/-) OCLs, in which neither protein is phosphorylated or associated with the osteoclast adhesion structure; 4) the association of p130(Cas) and PYK2 is mediated by the SH3 domain of p130(Cas) and the C-terminal domain of PYK2. These findings suggest that p130(Cas) and its association with PYK2 may play an important role in the adhesion-dependent signaling that leads to cytoskeletal reorganization and formation of the sealing zone during osteoclast activation.     

A Five-Year Master of Environmental Engineering Curriculum

The master's degree is essentially the entry-level degree for those wanting to practice environmental engineering. Although the BS∕MSCE (environmental emphasis) path produces graduates in high demand by employers, certain parts of the environmental engineering discipline demand graduates with a more specialized degree program. In response to the need for a specialized, or “professional,” degree program, Texas Tech offers an alternative to the traditional path to becoming an environmental engineer: the Master of Environmental Engineering (MEnvE) degree. The courses in the curriculum (EnvE course numbers) are taught by either civil or chemical engineering faculty. The MEnvE degree is a five-year “freshman-to-master's degree” program. The BS∕MSCE (environmental emphasis) degree program and the MEnvE program essentially require the same number of credit hours and many of the same courses. One principal difference between the two programs is that the BS∕MSCE path provides graduates with a broader civil engineering or chemical engineering background while the MEnvE program provides graduates with more concentrated preparation in biology, chemistry, chemical engineering, and environmental engineering. A second principal difference is that MEnvE graduates are focused on environmental engineering design. Thus, the MEnvE degree program is referred to as a professional degree program since graduates from the program typically enter professional practice rather than continue for a PhD degree.     

The balance hypothesis of renin release

Successful allogeneic hematopoietic transplants require conditioning regimens with sufficient immunosuppression to allow acceptance of the allograft. Cyclophosphamide, in combination either with TBI or with chemotherapeutic drugs, is the keystone of commonly used regimens. The toxicities of TBI and tumor resistance to cyclophosphamide create a niche for alternative, chemotherapy-based conditioning regimens. We report successful allogeneic stem cell transplantation after an ifosfamide-based regimen with ifosfamide 20 g/m2, carboplatin 1.8 g/m2 and etoposide 3 g/m2 (ICE) in divided doses over 6 days. Engraftment was prompt with neutrophils > or = 20 x 10(9)/l on day +10 and platelets > 20 x 10(9)/l on day +18. Engraftment of donor cells was documented by chromosome analysis and by VNTR analysis. An ifosfamide-based regimen provides sufficient immunosuppression for hematopoietic allograft acceptance in the absence of cyclophosphamide or of TBI.     

Microwave thermoradiotherapy for uveal melanoma: results of a 10-year study

OBJECTIVE: The purpose of the study is to evaluate clinically the use of microwave-heating (hyperthermia) as an adjuvant to ophthalmic plaque irradiation for treatment of patients with uveal melanoma. Hyperthermia was also used as a radiation sensitizer, allowing for significant dose reductions during ophthalmic plaque radiation therapy. PARTICIPANTS: In this case series, 48 patients were treated with microwave plaque thermotherapy for uveal melanoma. INTERVENTION: Microwave treatment, which involved affixing a miniature microwave dish antenna on the sclera beneath the tumor after completion of plaque brachytherapy, was performed. During hyperthermia treatment, the tumor's apex was targeted to receive a minimum of 42 degrees C for a 45-minute duration. A subset of 38 (79%) were given reduced apical doses of ophthalmic plaque radiation (radioactive isotope of iodine [125I] or palladium-103 [103Pd]) to an average of 52.6 Gy. MAIN OUTCOME PARAMETERS: Patients were evaluated for visual function, microwave toxicity, radiation oculopathy, eye retention, local tumor control, and metastatic disease. RESULTS: Patients have been observed for up to 10 years and for an average of 60 months (5 years). To date, there have been 3 cases of postoperative tumor enlargement (growth) for a 93.8% local control rate. Two patients were lost to follow-up. Seven eyes have been enucleated: three due to neovascular glaucoma, one due to uveitic neovascular glaucoma, and three due to progressive tumor enlargement. Although 15 patients have died, only 4 deaths were because of metastatic choroidal melanoma. Of the original 48 patients, 33 (69%) have maintained within 2 lines or have better than their preoperative visual acuity. Side effects attributable to heating have included decreased intraocular pressure without hypotony as well as chorioretinal scar formation within and around the targeted zone. CONCLUSIONS: The results of this series suggest that adjuvant microwave thermotherapy can be used with reduced doses of ophthalmic plaque radiation therapy to control the growth of uveal melanomas. Although the incidence of neovascular glaucoma, enucleation, and tumor regrowth is comparable to that of other series evaluating radiation alone, the visual acuities of microwave plaque thermotherapy-treated eyes were found to be superior.     

Sydenham Chorea: magnetic resonance imaging reveals permanent basal ganglia injury

We report the case of a 26-year-old man with diffuse esophageal leiomyomatosis involving the trachea. The tumor was resected by total esophagectomy and partial resection of the trachea and the left main bronchus. The tracheobronchial defect was repaired with a free forearm skin graft with satisfactory outcome. This approach offers good long-term prospects.