Neurofibromatosis type 1 gene haploinsufficiency reduces AP-1 gene expression without abrogating the anabolic effect of parathyroid hormone

Approximately 50% of neurofibromatosis type 1 (NF1) patients exhibit skeletal pathology, such as premature osteoporosis or pseudoarthroses. Loss of neurofibromin deregulates Ras signal transduction to affect generation of mitogen-activated protein kinase and Akt, both of which have been implicated in parathyroid hormone (PTH) anabolic mechanisms. Our aim was to determine if loss of neurofibromin impaired the anabolic effect of PTH on bone mass. Nf1 heterozygote (Nf1(+/-)) and wild type (Nf1(+/+)) mice were treated with recombinant human PTH(1-34) or vehicle once daily for 3-28 days. PTH enhanced mRNA expression of c-fos, junB, and fra2 in the distal femur metaphyses of both genotypes; expression of these transcripts was consistently lower in PTH-treated Nf1(+/-) mice. Despite lowered c-fos expression in Nf1(+/-) mice, PTH increased bone mass equivalently in both genotypes by 28 days. Ex vivo, Nf1 heterozygosity was associated with increased inducible osteoclasts in PTH-treated bone marrow cells and impairment of the actin stress fiber and cyclic adenosine monophosphate response to PTH in osteoprogenitors. Lower c-fos expression was previously thought to abrogate PTH responsiveness. Our results suggest crosstalk might occur between Ras signal transduction and the protein kinase A pathway in Nf1(+/-) mice. Ras signal transduction does not appear to be essential for the anabolic actions of PTH on bone. Because PTH was effective in the absence of Nf1, it may offer a useful approach to treat osteoporosis in NF1 patients.

Lymphome oculaire de type MALT simulant une sclérite ou une uvéite postérieure

PURPOSE

Diagnostic and therapeutic management of masquerade syndromes associated with MALT-type lymphoma.

PATIENTS AND METHOD

We report the cases of three patients referred for acute or chronic severe loss of visual acuity. All of them suffered from uveitis or scleritis resistant to corticoid treatment. Each one had posterior uveitis associated with retinochoroidal infiltration, anterior scleritis associated with uveal effusion syndrome, or bilateral pan-uveitis associated with serous retinal detachment. Two patients had medical records of systemic malignancies. They underwent an extensive work-up. Search for an infectious, immune or malignant disease was negative but orbital imaging showed a posterior scleral thickening in all cases.

RESULTS

Diagnosis of mucosa-associated lymphoid tissue (MALT) ocular lymphoma was assessed in all cases after scleral biopsy. Immunohistochemical analysis showed CD20(+) and CD5(-) scleral lymphocyte infiltrates. The three patients underwent chemotherapy associated with radiotherapy. Lesions were stabilized in the first case, whereas six lines of visual acuity improvement was noted in the second one, and full recovery was achieved after treatment in the third case.

DISCUSSION

Clinical manifestations of this ocular lesion seem to be multiple, masquerading as different types of posterior uveitis or scleritis. In the three cases, we did found other systemic locations of MALT-type lymphoma. Diagnosis was mainly based on pathological analysis. Fast visual recovery in two cases demonstrated the importance of an early diagnosis and a specific treatment. All cases of chronic and corticoid-resistant posterior uveitis require a specialized radiological evaluation followed, if necessary, by multiple orbital biopsies.

Electromyography and computed tomography scan-guided fine needle aspiration biopsy of discrete extraocular muscle metastases

Discrete or isolated metastasis to the extraocular muscles without an accompanying intraconal or extraconal mass is rare. Although it is estimated that 5% of orbital metastasis involves extraocular muscles only, to our knowledge there are no reports of discrete extraocular muscle involvement from renal cell carcinoma. With discrete extraocular muscle involvement, accurate localization within the infiltrated region of the muscle is of paramount importance in achieving a safe and positive biopsy. We describe a case with discrete extraocular muscle metastasis from a renal cell carcinoma, where a novel technique of FNAB (fine needle aspiration biopsy) of the medial rectus was undertaken, with EMG (electromyography) control and CT (computerized tomography) scan guidance.

Orbital presentations of giant cell arteritis

BACKGROUND

giant cell arteritis (GCA) is a systemic vasculitis that may affect the optic nerve and cause blindness (e.g. ischemic optic neuropathy). Orbital inflammatory disease, however, is an uncommon presentation of GCA.

PURPOSE

to alert clinicians to the orbital presentations of GCA.

PATIENTS AND METHODS

a retrospective case series from tertiary care academic ophthalmic referral centers of four patients with orbital manifestations of giant cell arteritis.

RESULTS

presentation of cases and review of the literature. In three cases, a temporal artery biopsy was diagnostic of GCA, but in one case, an orbital biopsy was needed to confirm the diagnosis.

CONCLUSION

GCA can have orbital manifestations and clinicians should be aware of this unusual presentation of GCA in cases of presumed orbital inflammatory pseudotumor in the elderly.

MADD victim impact panels and stages-of-change in drunk-driving prevention

OBJECTIVE

To assess the additional effects of Mothers Against Drunk Driving (MADD) Victim Impact Panels (VIPs) over the effects of a DWI (driving while intoxicated) school, on (1) moving individuals through the stages-of-change toward not drinking while driving and (2) drunk-driving recidivism.

METHOD

A randomized experiment with 813 (75% male) DWI offenders in New Mexico measured progress through the stages-of-change at pretest, posttest, 1-year follow-up and 2-year follow-up. In addition, drunk-driving recidivism over 2 years was measured from state driving records. Individuals were randomly assigned to a DWI school or a DWI school plus a MADD VIP.

RESULTS

No significant difference in movement through the stages-of-change, or in recidivism, occurred between respondents in the DWI-school-only treatment, and those in the DWI school plus VIP treatment.

CONCLUSIONS

There was no additional effect of the MADD VIP, a relatively emotional intervention, over that of the DWI school, a relatively informational approach, on DWI behavior (whether measured by stages-of-change or by DWI rearrest data) over the 2-year period following the two interventions.

Orthopaedic manifestations in de Barsy syndrome

de Barsy syndrome is a rare, genetically transmitted condition characterized by severe cutis laxa, joint hypermobility, growth retardation, mental retardation, and characteristic facies. Affected individuals have many orthopaedic manifestations, including developmental dysplasia of the hip, scoliosis, multiple joint dislocations and subluxations, and congenital vertical talus. The management of the orthopaedic manifestations of this syndrome is presented in two typical cases.

The Cbl protooncogene product: from an enigmatic oncogene to center stage of signal transduction

The c-cbl protooncogene was first identified as the cellular homologue of a viral oncogene v-cbl that induces pre-B lymphomas and myeloid leukemias in mice. Until recently, the biochemical basis for Cbl's transforming potential and its physiological role remained unclear. However, a convergence of biochemical studies in mammalian cells and genetic studies in C. elegans and Drosophila has now identified Cbl as a negative regulator of tyrosine kinase signaling. The N-terminal transforming region of Cbl (Cbl-N) and an adjacent RING finger domain are the elements most conserved during evolution. The Cbl-N region has now been shown to contain a novel phosphotyrosine-binding (PTB) domain that directly interacts with autophosphorylated tyrosine kinases via a D(N/D)XpY motif. A critical role of the PTB domain in Cbl function is demonstrated by the localization of a loss-of-function mutation in C. elegans Cbl homologue SLI-1 within this region. The corresponding mutation in human Cbl inactivates the PTB domain function and abrogates Cbl-mediated regulation of tyrosine kinase function. Recent studies have also identified a novel signaling pathway initiated by the interaction of mammalian Cbl proteins with the SH2 domains of Crk adaptor molecules, which results in Cbl's linkage with C3G, a guanine nucleotide exchange protein for Rap1 family of small G-proteins. Presently, Rap1 is thought to antagonize Ras function, although Rap1-specific targets have emerged recently. Thus, recent advances have firmly placed the little known protooncoprotein Cbl on the center stage of tyrosine kinase-mediated signal transduction.

Bilateral, simultaneous, spontaneous rupture of quadriceps tendons without trauma in an obese patient: a case report

This is a single case report of bilateral, simultaneous, spontaneous rupture of the quadriceps tendon caused by obesity without trauma. The patient was a 52-year-old, 350-pound, morbidly obese man with a sedentary life style whose quadriceps tendons ruptured while he was descending a staircase. He presented with a large deficit superior to the patella and an inability to straighten his knees. After surgery, his knees were immobilized in extension for 6 weeks, followed by gradual weight bearing and gait training with braces. He was weaned off the braces as he increased the range of motion and strength in his knees. The rehabilitation process was protracted, and he returned to full-time work 6 months postinjury. Physiatrists should be familiar with the diagnosis, treatment, and rehabilitation of this rare condition.

Invasive aspergillosis outbreak on a hematology-oncology ward

An outbreak of invasive aspergillosis occurred in a community hospital in temporal association with construction activity. Epidemiological investigation showed that patients who are at highest risk comprise a small group and are readily identifiable. Clinicians should strive to protect these patients, following guidelines published by the Centers for Disease Control and Prevention.

Preliminary results of a randomized controlled trial of prophylactic shock wave lithotripsy for small asymptomatic renal calyceal stones

OBJECTIVE

To report a prospective, randomized study to determine whether prophylactic extracorporeal shockwave lithotripsy (ESWL) is justified as a treatment for small, asymptomatic calyceal stones.

PATIENTS AND METHODS

The study included 228 patients with small (< 15 mm total diameter) asymptomatic calyceal stones; 113 patients were randomized to undergo ESWL and 115 to the control group who were kept under observation. Outcome measurements included the stone-free rate, requirement for additional treatment, symptoms, quality of life and renal function.

RESULTS

In all, 200 patients had at least one annual follow-up; all outcome measurements reported were those at the most recent follow-up (mean 2.2 years, range 1-5). In the ESWL group 28 patients (28%) were stone-free, compared with 16 (17%) in the observation group (odds ratio 1.95, 95% confidence interval, CI, 0.97-3.89, P = 0.06). Additional treatment in the form of analgesics, antibiotics, ESWL, stent insertion and ureteroscopy, was required in 21 (21%) patients in the observation group and 15 (15%) in the ESWL group (odds ratio 0.66, 95% CI 0.32-1.37, P = 0.27). Ten patients in the observation group required invasive procedures, vs none in the ESWL group. There was no evidence of differences in the symptoms, quality of life or renal function tests between the arms of the trial at the final follow-up.

CONCLUSIONS

Prophylactic ESWL for small asymptomatic renal calyceal stones does not appear to offer any advantage to patients in terms of stone-free rate, quality of life, renal function, symptoms or hospital admissions. However, a policy of observation is associated with a greater risk of requiring more invasive procedures. A longer follow-up is required to assess the validity of these preliminary findings.

Characterization of the Co(2+) and Ni(2+) binding amino-acid residues of the N-terminus of human albumin. An insight into the mechanism of a new assay for myocardial ischemia

Patients suffering from myocardial ischemia reportedly exhibit reduced in vitro binding of exogenous Co(2+) to the N-terminal of human serum albumin (HSA). The purpose of our investigation was to simulate changes in the N-terminus of HSA that may account for these ischemia-induced modifications to the cobalt binding site. HPLC, LC-MS and (1)H NMR analyses have shown that the N-terminal region of HSA Asp-Ala-His-Lys binds the transition metals Co(2+) and Ni(2+). Synthetic peptides with the first 2-12 amino acids of the HSA sequence demonstrated that the first three amino acids, Asp-Ala-His, are essential for strong binding of cobalt. Modification of the N-terminus peptide of HSA by way of N-acetylation or the deletion of one or more amino acid resulted in no binding of cobalt. Because the degradation of the susceptible, specific transition metal binding site of HSA may account for the decreased cobalt binding observed during ischemic events, an assay that detects this reduced binding could be useful in the diagnosis of ischemia.

Motivational Beliefs, Study Strategies, and Mathematics Attainment in High- and Low-Achieving Chinese Secondary School Students

In order to examine the relationship between cognitive and motivational variables and their relationship to mathematics attainment, Hong Kong-Chinese students enrolled in schools for high-, average-, and low-achievers completed questionnaires in Year 10 and in Year 11. Low-achievers perceived academic learning as being less useful over time and reported spending less time studying in Year 10 than in Year 11 but high- and low-achievers did not differ on their use of self-regulated learning strategies. Performance on the public examination in mathematics was predicted by prior achievement and Self-Concept of Mathematics Ability. Results underscore the importance of considering cultural beliefs systems and educational systems in models of academic motivation. Copyright 2000 Academic Press.

The relative rapidity of recanalization induced by recombinant tissue-type plasminogen activator (r-tPA) and TNK-tPA, assessed with enzymatic methods

BACKGROUND

Comparison of different plasminogen activators is difficult because conventional endpoints such as mortality are relatively insensitive to potential differences in efficacy with respect to rapidity of recanalization of infarct-related arteries.

METHODS

This study was performed to determine whether valid comparisons could be made by means of biochemical endpoints that have been demonstrated previously to permit estimation of the time of opening of an infarct-related artery in experimental animals and in patients. The method is based on time-dependent interconversion of isoforms of creatine kinase mediated by carboxypeptidase N, an enzyme present in excess in circulating blood. A small subset of 39 patients studied in the ASsessment of the Safety and Efficacy of a New Thrombolytic agent (ASSENT-2) trial were evaluated to determine the feasibility of using the creatine kinase isoform method for comparison of two tissue-type plasminogen activators (tPA), recombinant tPA (r-tPA) and TNK-tPA.

RESULTS

Early recanalization (within 40 min of the onset of treatment with the plasminogen activator) occurred in 56% of patients treated with r-tPA and 76% of those treated with TNK-tPA.

CONCLUSIONS

Differences in the efficacy of plasminogen activators with respect to rapidity of recanalization appear to be readily detectable by means of assaying creatine kinase isoforms in serially acquired blood samples under conditions that permit widespread application of the approach developed.

Physical and cDNA mapping in the DBH region of human chromosome 9q34

Chromosome 9q34 has been extensively studied and mapped due to the presence of known disease genes, principally tuberous sclerosis 1 (TSC1), in this region. During the course of our mapping of this region we constructed a 555-kb contig beginning approximately 50 kb proximal to the dopamine-beta-hydroxylase (DBH) gene and extending, with one small deletion, distal to the D9S114 marker. The contig consists of 11 P1 clones, four PAC clones, one BAC clone and six cosmid clones and contains 27 new nonpolymorphic STSs. We have found the region to be unstable in P1, PAC and BAC cloning vehicles and have identified several deleted genomic clones. In addition, we have isolated and mapped the 3' portions of three putative genes located within or immediately distal to the DBH gene, including one large gene that runs on the opposite strand to DBH and utilizes portions of two DBH exons. The genomic clones of the contig, cDNAs and new STSs will be useful reagents for the further study and mapping of this region.