Multiple myeloma lesion detection with whole body CT versus radiographic skeletal survey.

OBJECTIVE: To compare accuracy of CT versus radiographs in detecting myeloma lesions. MATERIALS AND METHODS: Retrospective review of patients who were simultaneously evaluated with radiographs and PET/CT scans. Two radiologists independently assessed each modality. RESULTS: Total number of lesions detected with CT was 968 versus 248 for radiographs (p < .001). Nine patients (18%) had no lesions on either CT or radiographs. Of the remaining 42 patients, 39 had more lesions on CT. CT could have resulted in upstaging of disease in 31 cases (61%). CONCLUSION: CT is superior for detecting myeloma lesions.

Reevaluation of the requirement for TIP47 in human immunodeficiency virus type 1 envelope glycoprotein incorporation.

Incorporation of the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins into assembling particles is crucial for virion infectivity. Genetic and biochemical data indicate that the matrix (MA) domain of Gag and the cytoplasmic tail of the transmembrane glycoprotein gp41 play an important role in coordinating Env incorporation; however, the molecular mechanism and possible role of host factors in this process remain to be defined. Recent studies suggested that Env incorporation is mediated by interactions between matrix and tail-interacting protein of 47 kDa (TIP47; also known as perilipin-3 and mannose-6-phosphate receptor-binding protein 1), a member of the perilipin, adipophilin, TIP47 (PAT) family of proteins implicated in protein sorting and lipid droplet biogenesis. We have confirmed by nuclear magnetic resonance spectroscopy titration experiments and surface plasmon resonance that MA binds TIP47. We also reevaluated the role of TIP47 in HIV-1 Env incorporation in HeLa cells and in the Jurkat T-cell line. In HeLa cells, TIP47 overexpression or RNA interference (RNAi)-mediated depletion had no significant effect on HIV-1 Env incorporation, virus release, or particle infectivity. Similarly, depletion of TIP47 in Jurkat cells did not impair HIV-1 Env incorporation, virus release, infectivity, or replication. Our results thus do not support a role for TIP47 in HIV-1 Env incorporation or virion infectivity.

The HIV-1 matrix protein does not interact directly with the protein interactive domain of AP-3δ.

During the late phase of the Human Immunodeficiency Virus Type-1 (HIV-1) replication cycle, viral Gag proteins and the intact RNA genome are trafficked to specific sub-cellular membranes where virus assembly and budding occurs. Targeting to the plasma membranes of T cells and macrophages is mediated by interactions between the N-terminal matrix (MA) domain of Gag and cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5)P(2)] molecules. However, in macrophages and dendritic cells, a subset of Gag proteins appears to be targeted to tetraspanin enriched viral compartments, a process that appears to be mediated by MA interactions with the Delta subunit of the cellular Adaptor Protein AP-3 (AP-3δ). We cloned, overexpressed and purified the protein interactive domain of AP-3δ and probed for MA binding by NMR. Unexpectedly, no evidence of binding was observed in these in vitro experiments, even at relatively high protein concentrations (200µM), suggesting that AP-3δ plays an alternative role in HIV-1 assembly.

Hydrogen/deuterium exchange analysis of HIV-1 capsid assembly and maturation.

Following budding, HIV-1 virions undergo a maturation process where the Gag polyprotein in the immature virus is cleaved by the viral protease and rearranges to form the mature infectious virion. Despite the wealth of structures of isolated capsid domains and an in vitro-assembled mature lattice, models of the immature lattice do not provide an unambiguous model of capsid-molecule orientation and no structural information is available for the capsid maturation pathway. Here we have applied hydrogen/deuterium exchange mass spectrometry to immature, mature, and mutant Gag particles (CA5) blocked at the final Gag cleavage event to examine the molecular basis of capsid assembly and maturation. Capsid packing arrangements were very similar for all virions, whereas immature and CA5 virions contained an additional intermolecular interaction at the hexameric, 3-fold axis. Additionally, the N-terminal ß-hairpin was observed to form as a result of capsid-SP1 cleavage rather than driving maturation as previously postulated.

The p12 domain is unstructured in a murine leukemia virus p12-CA(N) Gag construct.

The Gag polyproteins of gammaretroviruses contain a conserved p12 domain between MA and CA that plays critical roles in virus assembly, reverse transcription and nuclear integration. Here we show using nuclear magnetic resonance, that p12 is unstructured in a Moloney murine leukemia virus (MMLV) Gag fragment that includes the N-terminal domain of CA (p12-CA(N)). Furthermore, no long range interactions were observed between the domains, as has been previously predicted. Flexibility appears to be a common feature of Gag "late" domains required for virus release during budding. Residues near the N-terminus of CA(N) that form a beta-hairpin in the mature CA protein are unfolded in p12-CA(N), consistent with proposals that hairpin formation helps trigger capsid assembly.

Experience with the gold weight and palpebral spring in the management of paralytic lagophthalmos.

BACKGROUND: The loss of the blink reflex and the ability to close the eye actively are disabling functional and aesthetic impairments common to patients with facial paralysis. Nonphysiologic (static) management techniques involve implantation of devices in the upper eyelid that mechanically aid eye closure. The most popular devices are the gold weight and the palpebral spring. The authors' experience with these devices is presented. METHODS: Thirty-nine patients treated for paralytic lagophthalmos by the senior author (J.K.T.) between 1987 and 2002 met the inclusion criteria. Eighteen patients received the gold weight and 21 received the palpebral spring. From standardized video records, preoperative and postoperative blink scores were calculated. RESULTS: Fifty-nine percent of the patients (23 of 39) were female, and the most common cause for facial paralysis [35.9 percent (14 of 39)] was extirpation of acoustic neuroma and other cerebellopontine lesions. Fifty percent of the gold weight cohort was younger than 20 years at the time of surgery, with almost 40 percent (seven of 18) younger than 10 years. In the palpebral spring group, 14.3 percent (three of 21) were younger than 20 years, with 4.8 percent (one of 21) younger than 10 years. The palpebral spring group obtained a larger postoperative mean blink score of 34.0 +/- 12.4 percent compared with the gain of 21.4 +/- 14.6 percent (p = 0.025) by the gold weight group. CONCLUSION: The gold weight and palpebral spring are both effective in restoring motion to the paretic upper eyelid, but the palpebral spring is more so despite the frequent need for revisions.

Minitendon graft transfer for suspension of the paralyzed lower eyelid: our experience.

BACKGROUND: : Restoration of eyelid animation and aesthetics is a major component of the surgical management of facial paralysis. The authors' experience with the minitendon graft (a piece of split palmaris tendon graft) for lower eyelid suspension is presented. The effect of age, cause, denervation time, and total number of procedures performed in the eye region are analyzed. METHODS: : Fifty-eight patients with facial paralysis presenting with paralytic ectropion received the minitendon graft for lower eyelid suspension. Twenty-eight patients with concurrent lagophthalmos received the eye spring (n = 14) or gold weight (n = 14). Scleral show and lagophthalmos were measured by the same investigator (S.A.K.) using the methodology established by Terzis and Bruno. Outcomes were graded as follows: grade 1, no change; grade 2, minimal change; grade 3, moderate change; grade 4, good (more than half decrease); and grade 5, excellent, no scleral show or lagophthalmos. RESULTS: : Seventy percent of the patients were female, and in 40 percent the cause was developmental. There was clear improvement in both scleral show and lagophthalmos (p < 0.001). More than 80 percent of the outcomes were graded as good to excellent for both scleral show and lagophthalmos. There was correlation between age and cause, but neither affected outcomes. Denervation time had no influence on the results (p = 0.942). CONCLUSION: : The minitendon graft for lower eyelid suspension is an effective technique for repositioning the paralyzed lower eyelid regardless of patient age, denervation time, or cause of injury, and may be effectively combined with the eye spring or gold weight in the presence of lagophthalmos.

Structure of the antiviral assembly inhibitor CAP-1 complex with the HIV-1 CA protein.

The CA domain of the human immunodeficiency virus type 1 (HIV-1) Gag polyprotein plays critical roles in both the early and late phases of viral replication and is therefore an attractive antiviral target. Compounds with antiviral activity were recently identified that bind to the N-terminal domain of CA (CA N) and inhibit capsid assembly during viral maturation. We have determined the structure of the complex between CA N and the antiviral assembly inhibitor N-(3-chloro-4-methylphenyl)-N'-{2-[({5-[(dimethylamino)-methyl]-2-furyl}-methyl)-sulfanyl]ethyl}-urea) (CAP-1) using a combination of NMR spectroscopy and X-ray crystallography. The protein undergoes a remarkable conformational change upon CAP-1 binding, in which Phe32 is displaced from its buried position in the protein core to open a deep hydrophobic cavity that serves as the ligand binding site. The aromatic ring of CAP-1 inserts into the cavity, with the urea NH groups forming hydrogen bonds with the backbone oxygen of Val59 and the dimethylamonium group interacting with the side-chains of Glu28 and Glu29. Elements that could be exploited to improve binding affinity are apparent in the structure. The displacement of Phe32 by CAP-1 appears to be facilitated by a strained main-chain conformation, which suggests a potential role for a Phe32 conformational switch during normal capsid assembly.