Mapping of epitopes exposed on intact human immunodeficiency virus type 1 (HIV-1) virions: a new strategy for studying the immunologic relatedness of HIV-1

To study the antigenic conservation of epitopes of human immunodeficiency virus type 1 (HIV-1) isolates of different clades, the abilities of human anti-HIV-1 gp120 and gp41 monoclonal antibodies (MAbs) to bind to intact HIV-1 virions were determined by a newly developed virus-binding assay. Eighteen human anti-HIV MAbs, which were directed at the V2, V3 loop, CD4-binding domain (CD4bd), C5, or gp41 regions, were used. Nine HIV-1 isolates from clades A, B, D, F, G, and H were used. Microtiter wells were coated with the MAbs, after which virus was added. Bound virus was detected after lysis by testing for p24 antigen with a noncommercial p24 enzyme-linked immunosorbent assay. The anti-V3 MAbs strongly bound the four clade B viruses and viruses from the non-B clades, although binding was weaker and more sporadic with the latter. The degrees of binding by the anti-V3 MAbs to CXCR4- and CCR5-tropic viruses were similar, suggesting that the V3 loops of these two categories of viruses are similarly exposed. The anti-C5 MAbs bound isolates of clades A, B, and D. Only weak and sporadic binding of all the viruses tested with anti-CD4bd, anti-V2, and anti-gp41 MAbs was detected. These results suggest that V3 and C5 structures are shared and well exposed on intact virions of different clades compared to the CD4bd, V2, and gp41 regions.

Genetic instability in the 9q22.3 region is a late event in the development of squamous cell carcinoma

Squamous cell carcinoma (SCC) of the skin represents a group of neoplasms which is associated with exposure to UV light. Recently, we obtained data suggesting that invasive skin cancer and its precursors derive from one original neoplastic clone. Here, the analysis were extended by loss of heterozygosity (LOH) analysis in the chromosome 9q22.3 region. A total of 85 samples, taken from twenty-two sections of sun-exposed sites, corresponding to normal epidermis, morphological normal cells with positive immuno-staining for the p53 protein (p53 patches), dysplasias, cancer in situ (CIS) and squamous cell carcinomas (SCC) of the skin were analysed. Overall, about 70% of p53 patches had mutations in the p53 gene but not LOH in the p53 gene or 9q22.3 region. Approximately 70% of the dysplasias showed p53 mutations of which about 40% had LOH in the p53 region but not in the 9q22.3 region. In contrast, about 65% of SCC and CIS displayed LOH in the 9q22.3 region, as well as frequent (80%) mutations and/or LOH in the p53 gene. These findings strongly suggest that alterations in the p53 gene is an early event in the progression towards SCC, whereas malignant development involves LOH and alterations in at least one (or several) tumor suppressor genes located in chromosome 9q22.3.

Mefilm: an adherent polyurethane dressing for superficial wounds

Research has demonstrated that wounds heal faster in a moist environment. Film dressings are used to promote a moist environment. Mefilm is part of the Mölnlycke Health Care chronic wound care system and is a gentle, adherent polyurethane dressing. This product focus discusses the development of the semi-permeable film dressing, Mefilm, examining its uses, application and removal.

Melgisorb: a highly absorbent calcium/sodium alginate dressing

Alginates have been used in wound care for many years. In recent years alginate dressings have developed to provide an extremely cost-effective way of managing wounds with a moderate to high level of exudate. The dressing gel has traditionally been either soft or firm on removal, but with new technology softness and fast gelling may now be combined with high integrity in a single product. An example of such a product is Melgisorb from Mölnlycke Health Care (the makers of Mepore). Melgisorb is just one dressing in their range of chronic wound care products.

Current or recent proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test

BACKGROUND

There are increasing indications for assessing Helicobacter pylori status by non-invasive means in dyspeptic patients. There is also increasing use of proton pump inhibitor therapy for dyspeptic disease.

AIMS

To determine the effect of proton pump inhibitor therapy on the accuracy of the [14C]urea breath test.

PATIENTS

[14C]Urea breath tests were performed in 20 H. pylori-positive and 13 H. pylori-negative dyspeptic patients before commencing omeprazole and after 4 weeks of treatment with 40 mg/day and then 6 months of treatment with 20 mg/day. Further studies were done in H. pylori-positive patients to examine the time course of the onset and resolution of the effect observed.

RESULTS

False negative results occurred in 45% of the H. pylori-positive subjects after 4 weeks of omeprazole 40 mg/day and in 28% after 6 months of 20 mg/day. False positive results occurred in 15% of the H. pylori-negative subjects after 4 weeks of omeprazole 40 mg/day. In the H. pylori-positive subjects time course studies showed increasing suppression of the breath test result over the first 2-4 weeks of treatment. It took a similar time for the breath test result to recover after stopping treatment. There was no significant change in H. pylori IgG serology in the H. pylori-positive patients after 7 months of omeprazole treatment.

CONCLUSIONS

Proton pump inhibitor therapy markedly impairs the accuracy of the [14C]urea breath test and, in particular, produces a high proportion of false negative results. The effect is dose related and may persist for 2-4 weeks after stopping therapy. Patients should be carefully questioned about recent proton pump inhibitor therapy before accepting a negative breath test result as reliable.

Effect of a carbohydrate-electrolyte drink on endurance capacity during prolonged intermittent high intensity running

OBJECTIVE

To examine the effect of a carbohydrate-electrolyte solution on endurance capacity during prolonged intermittent running.

METHODS

Nine subjects (eight men and one woman) ran to exhaustion on a motorised treadmill on two occasions separated by at least 10 days. After an overnight fast, they performed repeated 15 second bouts of fast running (at 80% Vo2MAX for the first 60 minutes, at 85% Vo2MAX from 60 to 100 minutes of exercise, and finally at 90% Vo2MAX from 100 minutes of exercise until exhaustion), separated by 10 seconds of slow running (at 45% Vo2MAX). On each occasion they drank either a water placebo (P) or a 6.9% carbohydrate-electrolyte (CHO) solution immediately before the run (3 ml/kg body mass) and every 20 minutes thereafter (2 ml/kg body mass).

RESULTS

Performance times were not different between the two trials (112.5 (23.3) and 110.2 (21.4) min for the P and CHO trials respectively; mean (SD)). Blood glucose concentration was higher in the CHO trial only at 40 minutes of exercise (4.5 (0.6) v 3.9 (0.3) mmol/1 for the CHO and P trials respectively; p < 0.05), but there was no difference in the total carbohydrate oxidation rates between trials.

CONCLUSION

These results suggest that drinking a 6.9% carbohydrate-electrolyte solution during repeated bouts of submaximal intermittent high intensity running does not delay the onset of fatigue.

Acucise endopyelotomy: a successful therapeutic intervention in the treatment of ureteropelvic junction obstruction

Ureteropelvic junction obstruction is a well-recognized cause of pain and eventual renal failure. This condition may be congenital or it can develop secondary to renal calculi, infection, and instrumentation. Surgical intervention is the definitive therapy, and a number of surgical options are available to treat ureteropelvic junction obstruction. We describe an approach using the Acucise cutting balloon to perform retrograde endopyelotomy. In 12 patients making up 13 renal units, our success rate was 92.3%, at a mean follow-up of 8.4 months (range 2 to 21 months). Complications were minimal. Based on our experience, Acucise endopyelotomy is a successful therapeutic intervention in treating ureteropelvic junction obstruction.

Tackling strokes

The government's green paper sets specific targets for a reduction in the incidence of stroke. Carol Williams and Lynne Kendall look at the nurse's role in prevention and recovery.

Do c-Jun, c-Fos, and amyloid precursor protein play a role in neuronal death or survival?

A unilateral hypoxic-ischemic (HI) episode in immature rat brain was used to investigate the role of the immediate early genes c-fos and c-jun in delayed neuronal death and survival. This HI paradigm results in an apoptotic cell death in selectively vulnerable areas, in particular the hippocampal CA1 pyramidal cell layer. In susceptible regions undergoing delayed neuronal death there was a prolonged induction of both c-Jun and c-Fos (mRNA and protein). This expression occurred in parallel with a pronounced increase in AP-1 DNA binding activity but was not associated with either increased levels of Jun NH2-terminal kinase or phosphorylation of c-Jun (ser-63). In addition to changes in immediate early gene expression, the CA1 neurons showed a delayed increase in the expression of amyloid precursor protein (APP751) mRNA, suggesting that APP, which contains an AP-1 site, might be a down-stream gene regulated by the Jun transcription factor in neurons dying by apoptosis. The surviving dentate granule cells also showed an increase in Fos, Jun, and APP751 although this expression occurred earlier than in the CA1 neurons and declined rapidly. These results are discussed with respect to the role of these proteins in neuronal death and survival.

Pressure area management in an orthopaedic setting

Pressure area care for patients who have undergone a hip replacement is extremely difficult as patients' mobility tends to be restricted because of fear of dislocation. Orthopaedic surgeons influence the positional changes and techniques utilized by nurses in the postoperative period. This article reviews factors that prevent early rehabilitation and highlights methods of pressure relief for this patient group. Alternating-pressure mattresses are a main source of pressure-relieving equipment. A pilot study using the Nimbus II mattress was carried out to establish the role of alternating-pressure mattresses in the postoperative management of patients undergoing elective/emergency hip replacement surgery. None of the patients in the pilot study suffered prosthetic dislocation and 87% did not develop pressure sores. Three patients did develop a grade 2 pressure sore postoperatively. The results reinforce the use of alternating-pressure mattresses in the postoperative management of patients undergoing hip replacement surgery.

Structure of keratan sulfate from bonefish (Albula sp.) larvae deduced from NMR spectroscopy of keratanase-derived oligosaccharides

Structural details of keratan sulfate (KS) glycosaminoglycan, isolated from early-metamorphosing larvae (leptocephali) of bonefish (Albula sp.), are described. Bonefish KS was analyzed by first hydrolyzing the purified compound with KS endo-beta-galactosidase (keratanase) from Pseudomonas spp., and then examining the resulting oligosaccharides with reversed-phase high-performance liquid chromatography (HPLC) and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy at 400 MHz. Spectral analyses were performed by COSY and HMQC. The results showed that a single oligosaccharide was produced whose structure is consistent with that of a tetrasaccharide containing two, beta-linked, N-acetyllactosamine units. Enzymic evidence indicated that the internal galactose of the tetrasaccharide was O-sulfated at C-6, and that the reducing-end galactose was unsulfated. Spectral data for C-1 of the two galactose residues were consistent with the proposed sulfation pattern. In addition, spectral evidence confirmed that a C-6 on one of the sugars was sulfated: this sulfate was tentatively assigned to the internal galactose. Chemical studies have shown that an additional sulfate group is present, but its assignment could not be confirmed, owing to the complexity of the spectral data. The known specificities of keratanase, and the production of a single tetrasaccharide, however, require that the additional sulfate reside on C-6 of either of the two available N-acetylglucosamine (GlcNAc) moieties, and that it cannot alternate between the two. The inability of beta-N-acetylglucosaminidase from beef kidney to liberate GlcNAc from the tetrasaccharide provided preliminary support for the view that this sulfate is located on the nonreducing-end GlcNAc. We conclude that the native, high molecular weight (M(r) = 55,000) KS polymer from bonefish larvae consists of a disulfated disaccharide alternating with an unsulfated disaccharide in the adjacent N-acetyllactosamine unit, with this pattern repeating itself in a regular fashion along most, or all, of the chain. This structure could provide an explanation for the ability of bonefish KS chains to self-associate into dimers. Although the N-acetyllactosamine repeat is characteristics of KS in general, the sulfation pattern is different from that postulated for the well-characterized KS chains of lower molecular weight obtained from mammalian cornea and cartilage. An additional difference was the inability to demonstrate sialic acid in bonefish KS.

Clones of normal keratinocytes and a variety of simultaneously present epidermal neoplastic lesions contain a multitude of p53 gene mutations in a xeroderma pigmentosum patient

A patient with xeroderma pigmentosum group C was extensively examined for mutations in the p53 gene in normal skin exposed to varying degrees of sunlight and in excisional biopsies of basal cell cancer, squamous cell cancer, and squamous cell dysplasia. Seventy-three samples were analyzed by microdissection of small cell clusters, followed by PCR and direct DNA sequencing. In skin taken from areas that most likely had never been exposed to the sun, no mutations were found. However, in skin exposed to the sun, we observed a multitude of mutations in the p53 gene. UV light-induced mutations were found in all types of lesions, as well as in clusters of morphologically normal epidermal cells. Twenty-nine distinct mutations were found in exons 5-8, all missense or nonsense, of which 27 (93%) were UV-specific C --> T or CC --> TT transitions at dipyrimidine sites of the nontranscribed strand. Two types of normal skin areas containing p53 mutations were observed: areas that stain strongly with p53 antibody (p53 patches) and those that do not stain. Because no silent or intron mutations were found in these cell clusters, the alterations in the p53 gene of morphologically normal cells are likely to have resulted in a selective growth advantage. The poor correlation between mutations and morphological phenotypes demonstrates that p53 mutations alone do not determine the phenotypes observed.

Mutation analysis of UBE3A in Angelman syndrome patients

Angelman syndrome (AS) is caused by chromosome 15q11-q13 deletions of maternal origin, by paternal uniparental disomy (UPD) 15, by imprinting defects, and by mutations in the UBE3A gene. UBE3A encodes a ubiquitin-protein ligase and shows brain-specific imprinting. Here we describe UBE3A coding-region mutations detected by SSCP analysis in 13 AS individuals or families. Two identical de novo 5-bp duplications in exon 16 were found. Among the other 11 unique mutations, 8 were small deletions or insertions predicted to cause frameshifts, 1 was a mutation to a stop codon, 1 was a missense mutation, and 1 was predicted to cause insertion of an isoleucine in the hect domain of the UBE3A protein, which functions in E2 binding and ubiquitin transfer. Eight of the cases were familial, and five were sporadic. In two familial cases and one sporadic case, mosaicism for UBE3A mutations was detected: in the mother of three AS sons, in the maternal grandfather of two AS first cousins, and in the mother of an AS daughter. The frequencies with which we detected mutations were 5 (14%) of 35 in sporadic cases and 8 (80%) of 10 in familial cases.

Psychosocial determinants of alcohol use among minority youth living in public housing developments

Youth residing in low income, inner city, public housing developments might be extremely vulnerable to psychosocial risk factors associated with alcohol use. In this study, we developed and tested a model of alcohol etiology with 624 African-American and Hispanic 7th graders residing in public housing developments. The students completed questionnaires concerning their alcohol use, social influences on their drinking, their drinking attitudes and knowledge, their psychosocial skills, and demographic and behavioral control information. Logistic regression analyses indicated that social influences from adults, friends, and family members predicted alcohol use. Individual psychosocial characteristics, e.g., drinking refusal, lowered the odds of drinking. These findings imply that effective prevention approaches targeting minority urban youths residing in public housing developments should provide them with an awareness of social influences to drink, correct misperceptions concerning the prevalence of drinking, and train them in relevant psychosocial skills.

Cloning and characterization of ZNF189, a novel human Krüppel-like zinc finger gene localized to chromosome 9q22-q31

A 3-kb-long cDNA encoding a Krüppel-like human zinc finger protein was isolated and mapped to chromosome 9q22-q31. The ZNF189 gene encodes a protein with 16 zinc fingers at its C-terminus and belongs to the Krüppel-associated box (KRAB)-containing group of zinc finger proteins. Four differently spliced cDNA transcripts, differing at the 5' coding region where a KRAB A repressor domain is encoded, were isolated. In addition, Northern blot analysis indicates the presence of two additional unidentified splice variants. Comparison of cDNA and genomic sequences shows that the ZNF189 gene spans approximately 11 kb and is organized into at least four exons, the large 3'-end exon coding for the complete zinc finger domain and the 3' untranslated region. ZNF189 is expressed in all tissues and cell types currently investigated, at varying levels, but with a tissue- or cell-type-restricted expression pattern for the different splice variants. ZNF189 is conserved in the genome of several mammalian species. Direct sequencing of the ZNF189 gene in microdissected tumor biopsies of sporadic basal cell carcinoma and squamous cell carcinoma reveals no mutations in the coding sequence or at exon/intron boundaries.

3M Cavilon No Sting Barrier Film in the protection of vulnerable skin

Skin often becomes vulnerable in incontinent patients or following the use of aggressive adhesive tapes and dressings. Until recently the only products available for use on such skin have been ointments, creams and alcohol-based products. 3M Health Care has launched a range of no sting barrier film applicators that provide skin protection in many scenarios, but in a product that does not sting or cause pain on application.

Asphyxial brain injury--the role of the IGF system

Transient neural injuries, such as asphyxia, can trigger considerable delayed neuronal death. Inappropriate induction of apoptosis is thought to play an important role in this process. Our studies have shown marked changes in the IGF system in the brain in response to these injuries with an induction of insulin growth factor (IGF)-1 and insulin growth factor binding protein (IGFBP)-2 and IGFBP-3 in glial cells in the region of injury. This suggests that the IGF-1 system may be an endogenous neuroprotective system. Earlier administration of IGF-1 - 2 h after injury reduced the phase of secondary neuronal loss suggesting that IGF-1 may well have therapeutic potential as a neuronal rescue agent. The action of IGF-1 appears to involve binding proteins, transport to the site of injury and the IGF-1 receptor and inhibition of apoptosis, but might also involve generation of GPE which itself appears to be neuroprotective. Together these results indicate considerable potential of these agents to treat stroke, perinatal asphyxia and other forms of acute brain injury.

Tegagen alginate dressing for moderate to heavily exuding wounds

Traditionally known as 'the mariner's cure', alginates have been used as wound dressings for many years. Tegagen (formerly Tegagel) is an alginate dressing with improved performance from 3M. It is designed for a variety of wounds with moderate to high levels of exudate. Alginates are a very cost-effective treatment option for flat and cavity wounds of this type.