Treatment with PB125® Increases Femoral Long Bone Strength in 15-Month-Old Female Hartley Guinea Pigs.

Nuclear factor-erythroid 2-related factor-2 (Nrf2) is a transcription factor that serves as a master regulator of anti-inflammatory agents, phase I xenobiotic, and phase II antioxidant enzymes, all of which provide a cytoprotective role during disease progression. We hypothesized that oral administration of a purported phytochemical Nrf2-activator, PB125®, would increase long bone strength in aging Hartley guinea pigs, a model prone to musculoskeletal decline. Male (N = 56) and female (N = 56) guinea pigs were randomly assigned to receive daily oral treatment with either PB125® or vehicle control. Animals were treated for a consecutive 3-months (starting at 2-months of age) or 10-months (starting at 5-months of age) and sacrificed at 5-months or 15-months of age, respectively. Outcome measures included: (1) ANY-maze™ enclosure monitoring, (2) quantitative microcomputed tomography, and (3) biomechanical testing. Treatment with PB125® for 10 months resulted in increased long bone strength as determined by ultimate bending stress in female Hartley guinea pigs. In control groups, increasing age resulted in significant effects on geometric and structural properties of long bones, as well as a trending increase in ultimate bending stress. Furthermore, both age and sex had a significant effect on the geometric properties of both cortical and trabecular bone. Collectively, this work suggests that this nutraceutical may serve as a promising target and preventive measure in managing the decline in bone mass and quality documented in aging patients. Auxiliary to this main goal, this work also capitalized upon 5 and 15-month-old male and female animals in the control group to characterize age- and sex-specific differences on long bone geometric, structural, and material properties in this animal model.

Recent consensus on the classification of rhinosinusitis--a way forward for research and practice?

Prior classification of rhinitis was into three categories: acute, subacute and chronic rhinosinusitis. The advantages of this classification were obvious but they were offset by some disadvantages. For example, the previous classification did not take account of the mechanisms underlying the condition or the clinical outcome. Hence, there was a need for evidence-based sinusitis classification guidelines. The American Academy of Otolaryngology-Head and Neck Surgery and other related societies published a classification of the condition and suggested clinical research strategies for patients with rhinosinusitis. The main conclusion was that sinusitis should be divided into four categories: acute (bacterial) rhinosinusitis, chronic rhinosinusitis (CRS) without polyps, CRS with polyps, and allergic fungal sinusitis. The aim of this current paper is to discuss the consensus for nomenclature, outline the proposed classification of different types of rhinosinusitis and to suggest some ways that we may audit these guidelines.

Structure of RsrI methyltransferase, a member of the N6-adenine beta class of DNA methyltransferases.

DNA methylation is important in cellular, developmental and disease processes, as well as in bacterial restriction-modification systems. Methylation of DNA at the amino groups of cytosine and adenine is a common mode of protection against restriction endonucleases afforded by the bacterial methyltransferases. The first structure of an N:6-adenine methyltransferase belonging to the beta class of bacterial methyltransferases is described here. The structure of M. RSR:I from Rhodobacter sphaeroides, which methylates the second adenine of the GAATTC sequence, was determined to 1.75 A resolution using X-ray crystallography. Like other methyltransferases, the enzyme contains the methylase fold and has well-defined substrate binding pockets. The catalytic core most closely resembles the PVU:II methyltransferase, a cytosine amino methyltransferase of the same beta group. The larger nucleotide binding pocket observed in M. RSR:I is expected because it methylates adenine. However, the most striking difference between the RSR:I methyltransferase and the other bacterial enzymes is the structure of the putative DNA target recognition domain, which is formed in part by two helices on an extended arm of the protein on the face of the enzyme opposite the active site. This observation suggests that a dramatic conformational change or oligomerization may take place during DNA binding and methylation.

Structure of cyanase reveals that a novel dimeric and decameric arrangement of subunits is required for formation of the enzyme active site.

BACKGROUND: Cyanase is an enzyme found in bacteria and plants that catalyzes the reaction of cyanate with bicarbonate to produce ammonia and carbon dioxide. In Escherichia coli, cyanase is induced from the cyn operon in response to extracellular cyanate. The enzyme is functionally active as a homodecamer of 17 kDa subunits, and displays half-site binding of substrates or substrate analogs. The enzyme shows no significant amino acid sequence homology with other proteins. RESULTS: We have determined the crystal structure of cyanase at 1.65 A resolution using the multiwavelength anomalous diffraction (MAD) method. Cyanase crystals are triclinic and contain one homodecamer in the asymmetric unit. Selenomethionine-labeled protein offers 40 selenium atoms for use in phasing. Structures of cyanase with bound chloride or oxalate anions, inhibitors of the enzyme, allowed identification of the active site. CONCLUSIONS: The cyanase monomer is composed of two domains. The N-terminal domain shows structural similarity to the DNA-binding alpha-helix bundle motif. The C-terminal domain has an 'open fold' with no structural homology to other proteins. The subunits of cyanase are arranged in a novel manner both at the dimer and decamer level. The dimer structure reveals the C-terminal domains to be intertwined, and the decamer is formed by a pentamer of these dimers. The active site of the enzyme is located between dimers and is comprised of residues from four adjacent subunits of the homodecamer. The structural data allow a conceivable reaction mechanism to be proposed.

Crystal structures of penicillin acylase enzyme-substrate complexes: structural insights into the catalytic mechanism.

The crystal structure of penicillin G acylase from Escherichia coli has been determined to a resolution of 1.3 A from a crystal form grown in the presence of ethylene glycol. To study aspects of the substrate specificity and catalytic mechanism of this key biotechnological enzyme, mutants were made to generate inactive protein useful for producing enzyme-substrate complexes. Owing to the intimate association of enzyme activity and precursor processing in this protein family (the Ntn hydrolases), most attempts to alter active-site residues lead to processing defects. Mutation of the invariant residue Arg B263 results in the accumulation of a protein precursor form. However, the mutation of Asn B241, a residue implicated in stabilisation of the tetrahedral intermediate during catalysis, inactivates the enzyme but does not prevent autocatalytic processing or the ability to bind substrates. The crystal structure of the Asn B241 Ala oxyanion hole mutant enzyme has been determined in its native form and in complex with penicillin G and penicillin G sulphoxide. We show that Asn B241 has an important role in maintaining the active site geometry and in productive substrate binding, hence the structure of the mutant protein is a poor model for the Michaelis complex. For this reason, we subsequently solved the structure of the wild-type protein in complex with the slowly processed substrate penicillin G sulphoxide. Analysis of this structure suggests that the reaction mechanism proceeds via direct nucleophilic attack of Ser B1 on the scissile amide and not as previously proposed via a tightly H-bonded water molecule acting as a "virtual" base.

A thermophilic mini-chaperonin contains a conserved polypeptide-binding surface: combined crystallographic and NMR studies of the GroEL apical domain with implications for substrate interactions.

A homologue of the Escherichia coli GroEL apical domain was obtained from thermophilic eubacterium Thermus thermophilus. The domains share 70 % sequence identity (101 out of 145 residues). The thermal stability of the T. thermophilus apical domain (Tm>100 degrees C as evaluated by circular dichroism) is at least 35 degrees C greater than that of the E. coli apical domain (Tm=65 degrees C). The crystal structure of a selenomethione-substituted apical domain from T. thermophilus was determined to a resolution of 1.78 A using multiwavelength-anomalous-diffraction phasing. The structure is similar to that of the E. coli apical domain (root-mean-square deviation 0.45 A based on main-chain atoms). The thermophilic structure contains seven additional salt bridges of which four contain charge-stabilized hydrogen bonds. Only one of the additional salt bridges would face the "Anfinsen cage" in GroEL. High temperatures were exploited to map sites of interactions between the apical domain and molten globules. NMR footprints of apical domain-protein complexes were obtained at elevated temperature using 15N-1H correlation spectra of 15N-labeled apical domain. Footprints employing two polypeptides unrelated in sequence or structure (an insulin monomer and the SRY high-mobility-group box, each partially unfolded at 50 degrees C) are essentially the same and consistent with the peptide-binding surface previously defined in E. coli GroEL and its apical domain-peptide complexes. An additional part of this surface comprising a short N-terminal alpha-helix is observed. The extended footprint rationalizes mutagenesis studies of intact GroEL in which point mutations affecting substrate binding were found outside the "classical" peptide-binding site. Our results demonstrate structural conservation of the apical domain among GroEL homologues and conservation of an extended non-polar surface recognizing diverse polypeptides.

Tumor necrosis factor-alpha-induced apoptosis in prostate cancer cells through inhibition of nuclear factor-kappaB by an IkappaBalpha "super-repressor".

Prostate cancer patients experiencing a relapse in disease often express high serum tumor necrosis factor-alpha (TNF-alpha) levels. Many androgen-insensitive prostate cancer cells are TNF-alpha insensitive because of the expression of antiapoptotic genes as part of the nuclear factor-kappaB (NF-kappaB) family of transcription factors. NF-kappaB stimulates gene transcription when expressed in the nucleus; however, in resting cells, this nuclear import is prevented by association with the cytoplasmic inhibitor IkappaBalpha. This cytoplasmic retention of NF-kappaB is uncoupled by many extracellular signals including low levels of TNF-alpha. During normal cell activation, nuclear translocation of NF-kappaB is preceded by phosphorylation and degradation of IkappaBalpha. When phosphorylation is blocked, IkappaBalpha remains intact, thereby blocking NF-kappaB translocation to the nucleus and subsequent activation of antiapoptotic genes that cause TNF-alpha insensitivity. We tested whether a "super-repressor" of NF-kappaB activity could be transfected into prostate cancer cells and make them TNF-alpha sensitive. PC-3 and LNCaP cells were stimulated with TNF-alpha (10 ng/ml) for 24 h in the presence or absence of the IkappaBalpha "super-repressor" (p6R-IkappaB(S32A + S36A)). NF-kappaB activity was measured by electrophoretic mobility shift assay and the steady state levels of the cytoplasmic IkappaBalpha protein were measured by Western blot. Secretory IL-6 and IL-6 mRNA were measured by ELISA. p6R-IkappaB(S32A + S36A) blocked the stimulation of NF-kappaB activity by TNF-alpha in prostate cancer cells. It also subsequently decreased IL-6 production by TNF-alpha. We conclude that these data demonstrate that inhibition of NF-kappaB selectively sensitizes previously insensitive prostate cancer cells to TNF-alpha.

The changing face of lateral sinus thrombosis.

Lateral sinus thrombosis is a life threatening complication of middle ear disease, the presentation, diagnosis and management of which has seen many changes in recent times. While the introduction of antibiotics has been associated with a reduction in the incidence and associated morbidity/mortality of this complication, their use has also altered the clinical features of presentation, consequently diagnosis requires a high index of suspicion. Radiological advances, in particular magnetic resonance imaging and magnetic resonance venography, have improved our ability to diagnose this complication pre-operatively, and now are the diagnostic investigations of choice. Intraoperative sigmoid sinus exploration and removal of all necrotic clot are essential steps of surgical management together with appropriate antimicrobial treatment, however the role of anticoagulation therapy remains controversial. We present four recent cases of sigmoid sinus thrombosis and discuss the clinical presentation, investigation and management of this disease.

Psychiatry's image today: Results of an attitudinal survey.

The authors report the results of a survey designed to assess opinions and attitudes toward psychiatry among three groups of physicians and two groups of medical students. In general, the role of psychiatry was regarded favorably, and respondents' comments and criticisms were constructive and consistent. The authors suggest that the survey results may reflect an improvement in psychiatry's image.

Differences in tonsil core bacteriology in adults and children: a prospective study of 262 patients.

The tonsillar microflora of 262 patients with recurrent acute tonsillitis studied in 1989-1990 is presented. The patient population was divided into three age groups to determine any age-related features. One-hundred and forty-nine patients (57%) were in the 2-7-year-old group, 72 (28%) the 8-14-year-old age group, and the remaining 41 (15%) were over 15 years of age. H. influenzae was the single most common bacterium isolated from the centre of the tonsil (referred to as 'tonsil core'), and this was more prevalent in the 2-7-year-old age group. Staph aureus was the next most commonly isolated bacterium and was most frequently seen in the 8-14-year-old age group (29%). Anaerobic bacteriology was performed in 120 patients. Strict anaerobic species were isolated in significant numbers from the tonsil core in 5% but were present in the superficial culture in all. Anaerobes were present in moderate to heavy numbers in 32% of superficial swabs overall and this was more frequently seen in the older age groups. Mixed pathogens were found throughout all age groups and were most prevalent in the 8-14-year-old age group at 46%. The commonest mixture was H. influenzae and Staph aureus. Normal flora only was commonly found in the superficial swab and rarely in the tonsil core. The number of specimens containing a beta-lactamase producer was assessed for each group; this was similar in all of the groups ranging from 43% in the 2-7-year-old group and 53% in the 8-14-year-old group to 39% in the greater than 15-year-old group.

Bacteriology of tonsil and adenoid and sampling techniques of adenoidal bacteriology.

The value of pernasal swabs and direct adenoid swabs in chronic adenoid and adenotonsillar disease was assessed in 175 patients. Prior to adenoidectomy (53 patients) or adenotonsillectomy (122 patients), pernasal and direct adenoid swabs were taken. Adenoid currettings and tonsil tissue were cultured. Haemophilus influenzae was the bacterium most frequently isolated from adenoid currettings and from the centre (core) of the resected tonsil. There was a close relationship between the bacteriology of the pernasal swab and the adenoid tissue and tonsil core in 72 and 71% of patients, respectively. There was an identical profile of pathogens in 52 and 49%, respectively. We suggest that in children with adenoiditis or adenotonsillitis and hypertrophy of the adenoid, a pernasal swab should be used in preference to a throat swab in selecting appropriate antimicrobial therapy. Penicillin and ampicillin are not appropriate blind therapy in chronic adenoid and adenotonsillar infections because of the prevalence of beta-lactamase-producing aerobes (40%) in adenoid and tonsil core in these conditions.

Relationship between intracoronary and peripheral expression of soluble cell adhesion molecules.

BACKGROUND: Elevated levels of soluble cell adhesion molecules (sCAMs) have been reported in various coronary artery disease processes. The principle stimulus for expression of sCAMs is believed to be an inflamed atherosclerotic plaque within the coronary vessel. The relationship between levels of sCAMs in the coronary circulation and the peripheral circulation has not been defined. The primary aim of this study was to define the relationship between levels of sCAMs sampled from the systemic circulation and from the coronary circulation. We also set out to document the acute expression of soluble CAMs following coronary angioplasty with or without stent implantation. METHODS: The coronary sinus was cannulated in patients undergoing LAD angioplasty. Samples were drawn from left coronary ostium (LCO) and coronary sinus (CS) and femoral vein simultaneously before, immediately after and 4 h after the PTCA procedure. Levels of sICAM-1, sVCAM-1, sE-selectin and sP-selectin were measured using ELISA technique. RESULTS: 10 patients (7 male/3 female, 61+/-11 y) entered the study. There was no significant difference in the levels of sICAM-1, sVCAM-1, sE-selectin and sPselectin whether sampled from left coronary ostium, coronary sinus or femoral vein at all time points. There was no significant change in the acute expression of sICAM-1, sVCAM-1 and sE-selectin following coronary angioplasty. Levels of sP-selectin fell significantly during the PTCA procedure (142+/-7 ng/ml to 64+/-6 ng/ml, P<0.001) but then rose again after 4 h and returned toward baseline levels at 24 h. CONCLUSION: Levels of soluble CAMs sampled in the systemic circulation directly reflect levels in the coronary circulation. Coronary angioplasty results in rapid fall in levels of sP-selectin which returns to normal within 24 h following the procedure.

An alternative technique for nasal biopsy.

OBJECTIVES/HYPOTHESIS: The objective was to investigate the effectiveness of co-phenylcaine as a topical anesthetic agent for nasal mucosal biopsy. STUDY DESIGN: A prospective study. METHODS: Nasal mucosal biopsy specimens were taken from a site just anterior to the inferior turbinate following topical anesthesia with co-phenylcaine. All volunteers graded pain according to standard visual analogue scale (0-10) (VAS) scoring, and all were followed up after 24 hours for any epistaxis. RESULTS: Ninety nasal biopsy specimens were removed from 41 patients in all. Eight-two percent did not report any discomfort following this procedure (VAS score, 0). Ten patients reported mild discomfort (VAS scores ranging between, 1 and 3) and only six reported pain (VAS scores ranging from 5 to 7). However, five of these patients agreed to further biopsy and documented no discomfort during the repeat procedure. Only one patient required immediate intervention for hemorrhage after the procedure. In cases in which bleeding occurred (seven patients) it was documented within the first 6 hours, was minimal in content, and was controlled with local pressure. No systemic side effects were experienced. CONCLUSION: Co-phenylcaine is a suitable topical anesthetic agent for nasal mucosal biopsy. Removal of nasal tissue from a site anterior to the inferior turbinate can be performed under direct vision and provides sufficient tissue for histological assessment.

Somatostatin therapy for glomus tumors: a report of two cases.

Glomus tumors of the head and neck are benign vascular lesions that often provide dilemmas in management. The presence of somatostatin receptors on the tumor cell surface has facilitated an additional imaging technique in the form of radiolabeled octreotide scanning. The use of the somatostatin analogue, octreotide, also provides a therapeutic option for inoperable or recurrent tumors. We present two patients, one with a surgically inaccessible tumor that recurred after primary radiotherapy and one who underwent incomplete resection because of the tumor's proximity to the internal carotid artery. Neither tumor has shown further growth 5 and 3 years after treatment with octreotide, respectively.

Nasal granuloma gravidarum.

Nasal granuloma gravidarum is a rare condition that arises exclusively during pregnancy. It usually presents with the non-specific symptoms of nasal bleeding and obstruction though occasionally a patient may notice an intra-nasal mass herself. Three cases of nasal granuloma gravidarum are presented to add to those previously recorded in the literature. Although the aetiology of this condition is unclear, the authors speculate that it probably represents an excessive healing response to some minor trauma sustained in a tissue primed and sensitized by pregnancy. The management of this lesion is discussed and a simple surgical procedure described for its removal.

Sudden sensorineural hearing loss as a presentation of HIV infection.

Two case reports of HIV positive patients presenting with sudden sensorineural hearing loss are described. The importance of CT scanning and cerebrospinal fluid examination are stressed. The possible aetiology and pathology of the condition are also discussed.

Cervicofacial actinomycosis: an unusual cause of submandibular swelling.

Two cases of cervicofacial actinomycosis, resulting in submandibular swelling, are presented. How actinomycosis may present under the guise of malignancy is well demonstrated. Factors predisposing to the condition, difficulties with diagnosis, isolation methods of the causative organism and treatment of the disease, are discussed.

Surgical management of drooling in the neurologically damaged child.

Continuous drooling after infancy is rarely seen in normal children. Neurologically damaged children are more likely to continue to drool, and it may be so severe in some cases as to require surgical correction. Submandibular duct relocation is a procedure with minimal morbidity and excellent results. This procedure has been carried out on 16 children at the Eye and Ear Hospital and Temple Street Children's Hospital, Dublin, between the years 1982 to 1987. An overall improvement occurred in 13 cases with only one post-operative complication. Such surgery has transformed the lives of these children as well as being a great source of relief for the parents.

The Westaby T-Y tracheobronchial stent in otolaryngology.

The Westaby T-Y tracheobronchial silicone stent can be used for the relief of upper airway obstruction beyond the limit of a standard tracheostomy tube. We report on our experience in the use of the Westaby tube in 10 patients over a five-year period. The general features of the tube, indications for its use, and its method of insertion are described. The versatility and advantages over other stents are discussed. Two cases reports are described and the clinical course and outcomes of the individual patients are outlined.

Head and neck schwannomas--a 10 year review.

Schwannomas of the head and neck are uncommon tumours that arise from any peripheral, cranial or autonomic nerve. Twenty-five to 45 per cent of extracranial schwannomas occur in the head and neck region and thus are usually in the domain of the otolaryngologist. They usually present insidiously and thus are often diagnosed incorrectly or after lengthy delays, however, better imaging and cytological techniques have lessened this to some degree more recently. For benign lesions conservative surgical excision is the treatment of choice bearing in mind possible vagal or sympathetic chain injury. Malignant schwannomas are best treated with wide excision where possible. The role of adjuvant therapy remains uncertain and irrespective of treatment modality prognosis is poor with an overall survival of 15 per cent. However, recent advances in ras oncogene inhibitors may hold hope for the future.