Distribution of radiocarbon after intramammary, intrauterine, or ocular treatment of lactating cows with carbon-14 nitrofurazone

Three lactating Holstein cows (634 to 698 kg) were dosed, respectively, with 65.6 mg (44.5 microCi/mg), 131.2 mg (20.1 microCi/mg), or 8.4 mg (141.3 microCi/mg) of [14C]nitrofurazone by intramammary, intrauterine, or topical ocular administration. Intramammary and intrauterine treatments were single doses; ocular treatment was daily for 4 consecutive d (2.1 mg/d). Cows were slaughtered after 72-h withdrawal periods. Excreta and milk were quantitatively collected from each cow after dosing. Seventy-two hours after treatment, urine, feces, and milk contained 62.9, 17.6, and 2.3%, respectively, of the radiocarbon administered intramammarily to the cow. Radioactive residues in milk collected from the dosed quarter were 150 ppb (nitrofurazone equivalents) and were 39 ppb in milk collected from the undosed quarters at 12 h after dosing. Urine, feces, and milk from the cow that received the intrauterine dose contained 12.24, 5.17, and 0.13% of the administered dose, respectively, at 72 h after treatment. Concentrations of total radioactive residues in milk were 9.3 ppb at 12 h after dosing. For the cow that was dosed ocularly, the cumulative excretion of radiocarbon in urine, feces, and milk was 17.6, 28.5, and 0.5% of the dose, respectively. Milk residues from the cow that was dosed ocularly were never > 1 ppb of nitrofurazone equivalents. Livers and kidneys contained the greatest amounts of residues relative to other edible tissues. Parent nitrofurazone was not suitable as a marker compound to determine total residues in milk using HPLC analysis. Radioactive residues were available systemically and were excreted in milk after intramammary, intrauterine, or ocular application of [14C]nitrofurazone. Illegal residues in milk and edible tissues would result from the administration of nitrofurazone to lactating cows.

Melkersson-Rosenthal syndrome: reduction cheiloplasty utilizing a transmodiolar labial suspension suture

Melkersson-Rosenthal syndrome is a rare condition which consists of progressive and recurrent orofacial edema, intermittent facial palsy, and lingua plicata. Labial swelling is the most common feature of this syndrome complex. The lips may enlarge up to three times their normal size, resulting in aesthetic deformity and functional disability. Traditional medical interventions are only marginally successful in treating this syndrome. We present a case of Melkersson-Rosenthal syndrome with massive lower lip enlargement, which was successfully treated by combining a fleur-de-lis resection with a transmodiolar labial suspension suture. Five-year follow-up photographs are presented.

Transdermal delivery of nitric oxide from diazeniumdiolates

Adverse physiological effects can often interfere with the use of nitric oxide (NO) as a therapeutic agent, especially when it is systemically generated from prodrugs. NO which is generated and delivered site-specifically by transdermal donors may be useful in the treatment of parasitic, bacterial or viral skin infections without causing systemic side effects. Three diazeniumdiolates (formerly "NONOate"), including two water soluble compounds, (Z)-1-[N-2-aminoethyl)-N-(2-ammonioethyl)amino]-diazen-1- ium-1,2-diolate (DETA-NO) and (Z)-1-[N-(3-aminopropyl)-N-(3-ammoniopropyl)amino] diazen-1-ium-1,2-diolate (DPTA-NO), and one insoluble compound, DPTA-NO grafted to dextran microspheres (DPTA-NO-g-dextran) were used to transdermally deliver NO to rats. Dextran microspheres were obtained by simultaneously grafting DPTA-NO to dextran and cross-linking dextran with CNBr in an oil-water emulsion. Suspended in hydrogel, DETA-NO, DPTA-NO, and DPTA-NO-g-dextran were applied three times to depilated rats at 4 day intervals. Results show that metabolic urinary nitrate levels increase with time (24-48 h), reach a maximum, and return to baseline by the fourth day. DPTA-NO applications produced an average maximum nitrate level of 94.2 mumol/day +/- 34.2 mumol S.D. compared to the average maximum nitrate level of 39.8 mumol/day +/- 8.6 mumol S.D. obtained from treatment with DETA-NO. These results suggest that DPTA-NO delivered NO more efficiently than DETA-NO. When DPTA-NO-g-dextran microspheres were used as the NO donor, results comparable to DPTA-NO were observed with an average maximum nitrate level of 14.9 mumol/day +/- 3.0 mumol S.D. These and other conclusive data indicate that, via these diazeniumdiolates, NO can be delivered effectively through rat skin.

Characterization and nitric oxide release studies of lipophilic 1-substituted diazen-1-ium-1,2-diolates

Lipophilic esters of the naturally occurring polyamines putreanine and spermic acid were synthesized, characterized, and modified with nitric oxide to form the corresponding 1-substituted diazen-1-ium-1,2-diolates (previously known as NONOates). The resulting compounds were insoluble in water but were able to release nitric oxide (NO) when placed in phosphate buffered saline (PBS) at physiological pH. The two categories of compounds examined were putreanate esters of cholesterol or hexadecanol, and spermate diesters of cholesterol or hexadecanol. The putreanate NONOate esters of cholesterol and hexadecanol had NO release half-lives of 60 h and 81 h, respectively while the spermate NONOate diesters of cholesterol and hexadecanol and NO release half-lives of 23 days and 7.1 days, respectively. The presence of 5% Tween 20 increased the half-life of the cholesteryl putreanate NONOate to 104 h but only slightly increased the half-life of the hexadecyl putreanate NONOate to 89 h. The 1% presence of the pharmaceutical lung surfactant Survanta did not significantly alter the half-life of NO release for the cholesteryl putreanate NONOate or for the hexadecyl spermeate NONOate, but the surfactant did increase the amount of NO release by 46% and 67% respectively.

Antigen direction of specific T-cell clones into gingival tissues

This study was performed to investigate T-cell traffic to periodontal tissues during infection with a periodontal pathogen Actinobacillus actinomycetemcomitans (Aa). Rowett rat T-cell clones, A3 (CD4+ CD8-, alpha beta TCR+, NKRP-1-, specific to Aa) and G2 (CD4- CD8-, alpha beta TCR+, NKRP-1+, which reacts to Aa, Gram-negative and -positive bacteria), both expressed the same prominent adhesion molecules (LFA-1, VLA-4) to the same extent. Binding of both T-cell clones to rat endothelial cells in vitro was blocked by antibody to VLA-4. Rowett rats were infected with Aa and infused with Aa-stimulated, isogenic T-clone lymphocytes that had been labelled in vitro with 125IUdR. Radioactivity associated with recovery of clone A3, but not G2, was significantly elevated in the gingivae of infected rats, suggesting migration to infected animals' gingival tissues. Migration of radioactive Aa-specific A3 clone cells traced by autoradiography reached a maximum at 24 hr (1.2% of total lymphocytes as radiolabelled cells in infected gingiva versus 0.6% in noninfected), indicating an apparent antigen-directed retention in infected rats' gingival tissues. The G2 clone was not retained in the gingival tissues (0.20% of total lymphocytes as radiolabelled cells in infected gingiva versus 0.26% in non-infected). However, the possibility of A3 retention directed by inflammation or tissue-selective homing could not be excluded. In further experiments, other adoptively transferred T-clone lymphocytes [clones G23 (Th1) and F13 (Th2)] with specificity for the 29,000 MW outer membrane protein of Aa with the same prominent adhesion molecules could be recovered from rat gingivae previously challenged with this antigen. However, transferred T-clone lymphocytes [clone G26 (Th1)] with specificity for a different Aa antigen were not recovered. Therefore, the dynamics of cell entry into periodontal lesions vary for activated T lymphocytes with different antigenic specificities, indicating the significance of antigen in lymphocyte traffic to periodontal tissues.

The pharmacokinetics, metabolism, and tissue residues of beta-adrenergic agonists in livestock

Since the early 1980s the usefulness of dietary beta-agonists to improve the efficiency of feed utilization and(or) to enhance carcass leanness in livestock species has been well documented. Less well documented are the pharmacokinetic properties, biotransformation pathways, and tissue residue profiles of beta-agonists used to enhance leanness in experimentally or illegally treated animals. Pharmacokinetic data for clenbuterol, cimaterol, fenoterol, L-644,969, ractopamine, salbutamol, and terbutaline have been published but biotransformation and tissue residue studies for these compounds in livestock species are sparse. In general, beta-agonists having halogenated aromatic ring systems are metabolized by oxidative and conjugative pathways and have long plasma half-lives, whereas beta-agonists having hydroxylated aromatic rings are metabolized solely by conjugation and have relatively short plasma half-lives. Beta-Agonists having high oral bioavailabilities, long plasma half-lives, and relatively slow rates of elimination have high oral potencies in humans. Residues of such illegally used compounds in edible tissues of livestock represent a genuine risk to consumers. Conversely, beta-agonists having low oral bioavailabilities, short plasma half-lives, and rapid rates of elimination have low oral potencies in humans. Residues of such compounds in edible tissues of properly treated animals would not likely represent a credible risk to consumers of such products. The reviewed data indicate that the development of a safe and effective beta-agonist for use in livestock is possible.

Intratracheal instillation of a novel NO/nucleophile adduct selectively reduces pulmonary hypertension

We examined the pulmonary and systemic hemodynamic effects of administering soluble nitric oxide (NO) donor compounds (NO/nucleophile adducts, i.e., NONOates) directly into the trachea of animals with experimentally induced pulmonary hypertension. Steady-state pulmonary hypertension was created by using the thromboxane agonist U-46619. Yorkshire pigs were randomly assigned to one of four groups: group 1, intratracheal saline (control; n = 8); group 2, intratracheal sodium nitroprusside (n = 6); group 3, intratracheal ethylputreanine NONOate (n = 6); and group 4, intratracheal 2-(dimethylamino)-ethylputreanine NONOate (DMAEP/NO; n = 6). Pulmonary and systemic hemodynamics were monitored after drug instillation. Group 4 had significant reductions in pulmonary vascular resistance index (PVRI) at all time points compared with steady state and compared with group 1 (P < 0.05), whereas systemic vascular resistance index did not change. The mean change in mean pulmonary arterial pressure in group 4 was -33.1 +/- 1.2% compared with +6.4 +/- 1.3% in group 1 (P < 0.001), and the mean change in mean arterial pressure was -9.3 +/- 0.7% compared with a control value of -0.9 +/- 0.5% (P < 0.05). Groups 2 and 3 had significant decreases in both PVRI and systemic vascular resistance index compared with steady state and with group 1. In conclusion, intratracheal instillation of a polar-charged tertiary amine NONOate DMAEP/NO results in the selective reduction of PVRI. Intermittent intratracheal instillation of selective NONOates may be an alternative to continuously inhaled NO in the treatment of pulmonary hypertension.

Deriving shape space parameters from immunological data

We present a method for deriving shape space parameters that are consistent with immunological data, and illustrate the method by deriving shape space parameters for a model of cross-reactive memory. Cross-reactive memory responses occur when the immune system is primed by one strain of a pathogen and challenged with a related, but different, strain. Much of the nature of a cross-reactive response is determined by the quantity and distribution of the memory cells, raised to the primary antigen, that cross-react with the secondary antigen. B cells with above threshold affinity for an antigen lie in a region of shape space that we call a ball of stimulation. In a cross-reactive response, the intersection of the balls of stimulation of the primary and secondary antigens contains the cross-reactive B cells and thus determines the degree of cross-reactivity between the antigens. We derive formulas for the volume of intersection of balls of stimulation in different shape spaces and show that the parameters of shape space, such as its dimensionality, have a large impact on the number of B cells in the intersection. The application of our method for driving shape space parameters indicates that, for Hamming shape spaces, 20 to 25 dimensions, a three or four letter alphabet, and balls of stimulation of radius five or six, are choices that match the experimental data. For Euclidean shape spaces, five to eight dimensions and balls of stimulation with radius about 20% of the radius of the whole space, match the experimental data.

Immunogenicity and protective immunity induced by synthetic peptides associated with a catalytic subdomain of mutans group streptococcal glucosyltransferase

We examined the immunogenicity and induction of protective immunity of two 19-mer sequences (GGY and AND) which overlapped a highly conserved region which has recently been implicated in the enzymatic activity of glucosyltransferases (GTFs) of the mutans group streptococci. These peptides were synthesized as eight-branched constructs on a lysine core. Serum immunoglobulin G (IgG) antibody, induced by subcutaneous (s.c. [salivary gland vicinity]) injection with these peptide constructs, reacted with the inciting antigen, with mutans streptococcal GTFs, and with a 21-mer peptide (CAT) containing an aspartate previously shown to covalently bind sucrose. Several of these antisera also inhibited the ability of Streptococcus sobrinus GTF to synthesize insoluble glucan. Significant levels of salivary IgA antibody were also induced by GGY and AND peptide constructs after s.c. injection. The effect of immunization with the GGY and AND peptide constructs on the cariogenicity of Streptococcus mutans was studied in three experiments by immunization of weanling Sprague-Dawley rats, twice at 7- to 14-day intervals with peptides, S. sobrinus GTF, or phosphate-buffered saline. All rats were then orally infected with S. mutans SJ. After 63-day infection periods, the GGY and AND-injected groups had significant dental caries reductions compared with sham-injected groups in most experiments. These studies support the existence of an additional catalytic subdomain within the sequence defined by the GGY and AND peptides. Furthermore, the epitopes defined in these sequences have significant immunogenicity, can induce immune responses which interfere with GTF-mediated glucan synthesis in vitro, and can protect rats from experimental dental caries.

A mouse molecular mimic of human vascular adhesion protein-1

Human vascular adhesion protein-1 (VAP-1) is an endothelial sialoglycoprotein which exists in forms of Mr 90000 and 170000 and mediates lymphocyte binding to vessels under shear. VAP-1 is functionally defined by an inhibitory mouse mAb 1B2. A large-scale immunoaffinity purification of VAP-1 from human tonsil lysates was performed to determine the protein sequence for VAP-1 cDNA cloning. A dominant protein of molecular weight 90000 was obtained which yielded an N-terminal sequence of 20 amino acids which bore no significant identity to any protein sequence in the data banks. A mouse mAb (5B11) against a synthetic peptide from this sequence was raised and found to stain tissues in an identical manner to mAb 1B2, to inhibit lymphocyte adhesion to endothelial cells and to recognize VAP-1. Later, the N-terminal sequence obtained from the 1B2 immunoprecipitations was found to be identical to a mouse cyclophilin C associated protein (mCyCAP) subsequently published by others. We show here by several criteria at the protein and DNA level that VAP-1 is distinct from mCyCAP. Moreover, we elucidate the mechanism which results in binding of mCyCAP to mAb 1B2 during antibody synthesis in hybridoma cells and the sequelae of co-precipitation of mCyCAP during the immunoaffinity chromatography. Binding of mCyCAP to a mouse mAb has not been described before and suggests a new function for this molecule in immunoglobulin synthesis and/or secretion. Moreover, these data indicate that the N-terminal peptide of mCyCAP is a molecular mimic of a functionally important epitope of VAP-1.

Incorporation of nitric oxide-releasing crosslinked polyethyleneimine microspheres into vascular grafts

Over the years, many attempts have been made to increase the patency of small- to medium-sized prosthetic vascular grafts. However, none of them has greatly affected long-term rates. Recently, nitric oxide (NO) has been shown to inhibit thrombus formation in such grafts, suggesting that local delivery of NO may help to increase graft patency. This study describes the site-specific delivery of NO by entrapping NO-releasing microspheres in the pores of a vascular graft. NO-releasing polyethyleneimine microspheres (PEIX) were developed using a novel water-in-oil emulsion technique involving chemical crosslinking with a bis-epoxide. The PEIX microspheres were then derivatized with NO forming the [N(O)NO]- moiety of the diazeniumdiolates formerly known as NONOates. These polymeric NO-releasing particles were found to spontaneously release 194 nmol NO/mg with a half-life of over 66 h under physiologic conditions. Fluorescein isothiocyanate-labeled microspheres were then embedded into the pores of a 60-micron nonreinforced Gore-tex vascular graft using a simple evacuation technique and evaluated for microsphere placement and NO release. Scanning electron microscopic analysis showed the microspheres entrapped in the pores of the vascular graft releasing 10 nmol NO/mg with a half-life of 51 h. The microspheres remained entrapped in the graft even after immersion and NO release, as confirmed by fluorescence of the medium. These results suggest that NO-releasing particles can be incorporated into the pores of a vascular graft to deliver therapeutic amounts of NO for the prevention of thrombosis in small-diameter prosthetic grafts.

Functional screening and complex traits: human 21q22.2 sequences affecting learning in mice

Libraries of the mammalian genome have generally been propagated in single cells and have been used for gene discovery through in vitro analyses. We have expanded upon this concept by the creation of panels of YAC transgenic mice propagating targeted megabase regions of the genome. Such a panel of mice can be called an 'in vivo library' and genes can be identified based on functional screens of members of the library. To test this approach, we created a 2 Mb in vivo library of human chromosome 21q22.2. Analysis of the library has revealed that one 570 kb YAC, in two separate founder lines, was associated with distinct learning deficits compared with the other 21q22 YAC transgenics and non-transgenic control animals. We have localized the gene on the YAC that causes the deficits by taking advantage of fragmentation of the YAC during the process of microinjection. The responsible gene is the human minibrain gene, and the homolog of the gene in Drosophila is also associated with learning defects. These results suggest that altered dosage of minibrain is associated with abnormal neural development in flies and mice and, in humans, may also be involved in the molecular pathology of Down syndrome.

Characteristics of the new long-stay population in an inner Melbourne acute psychiatric hospital

OBJECTIVE

There has been an accumulation of so-called 'new long-stay' (NLS) patients in psychiatric hospitals. To date, no Australian studies have characterised this patient group. We aimed to study the demography, and clinical and social functioning of the NLS population at Royal Park Hospital (RPH) together with patients' attitudes to treatment and views on future placement.

METHOD

All 30 NLS patients at RPH were identified. Twenty-seven consenting patients were assessed using the following standardised instruments: Manchester Scale for psychopathology, Life Skills Profile (LSP), Physical Health Index and Patient Attitude Questionnaire. Information on past psychiatric history, past treatment and current treatment was collected. Insight and compliance were assessed.

RESULTS

The majority of patients were single men with a diagnosis of schizophrenia. Forty-one percent were detained in hospital involuntarily and 56% were considered dangerous to themselves or others. The patients were characterised by high levels of positive and negative symptoms. They were most impaired with respect to 'social contact' relative to the other subscales of the LSP. While 10 (48%) patients expressed a desire to leave hospital, only one patient considered that anyone would cohabit with them. Over two-thirds considered they had been unwell and that medication had helped. Staff rated one-third as having major problems with compliance. About two-thirds of patients had disability secondary to comorbid physical illnesses.

CONCLUSION

Like other NLS patients studied in the United Kingdom and Ireland, this group had significant handicaps secondary to psychiatric illness, concomitant physical illness and disability and behaviour unacceptable in community settings. They were also characterised by significant social isolation. These factors may be important determinants of rehabilitation failure and need to be addressed in the process of de-institutionalisation as well as in longitudinal studies examining these and other factors predicting NLS status.

Dose-dependent pain-facilitatory and -inhibitory actions of neurotensin are revealed by SR 48692, a nonpeptide neurotensin antagonist: influence on the antinociceptive effect of morphine

Neurotensin has bipolar (facilitatory and inhibitory) effects on pain modulation that may physiologically exist in homeostasis. Facilitation predominates at low (picomolar) doses of neurotensin injected into the rostroventral medial medulla (RVM), whereas higher doses (nanomolar) produce antinociception. SR 48692, a neurotensin receptor antagonist, discriminates between receptors mediating these responses. Consistent with its promotion of pain facilitation, the minimal antinociceptive responses to a 30-pmol dose of neurotensin microinjected into the RVM were markedly enhanced by prior injection of SR 48692 into the site (detected using the tail-flick test in awake rats). SR 48692 had a triphasic effect on the antinociception from a 10-nmol dose of neurotensin. Antinociception was attenuated by femtomolar doses, attenuation was reversed by low picomolar doses (corresponded to those blocking the pain-facilitatory effect of neurotensin) and the response was again blocked, but incompletely, by higher doses. The existence of multiple neurotensin receptor subtypes may explain these data. Physiologically, pain facilitation appears to be a prominent role for neurotensin because the microinjection of SR 48692 alone causes some antinociception. Furthermore, pain-facilitatory (i.e., antianalgesic) neurotensin mechanisms dominate in the pharmacology of opioids; the response to morphine administered either into the PAG or systemically was potentiated only by the RVM or systemic injection of SR 48692. On the other hand, reversal of the enhancement of antinociception occurred under certain circumstances with SR 48692, particularly after its systemic administration.

Maxillary sinusitis caused by Pleurophomopsis lignicola

An immunocompetent 59-year-old man developed sinusitis over a 6- to 8-month period after cutting down a rotted maple tree (Acer sp.). A polypoid obstruction with a bloody drainage was evident in his right nasal cavity. A computed tomographic scan showed an opacification of the maxillary sinus. Surgery was performed to remove a fungus ball that had extended into the patient's medial sinus cavity. Sections of the sinonasal mucosa revealed marked acute and chronic sinusitis with inflammation, congestion, and hemorrhage. Sections from the pasty brown to black debrided material revealed a fungus ball consisting of an extensive network of brown-pigmented, septate, profusely branched hyphae. When grown on oat agar, the phaeoid fungus produced pycnidia and was identified as Pleurophomopsis lignicola. The genus Pleurophomopsis includes seven species, which are all known from plant material. This report documents for the first time a coelomycetous fungus, P. lignicola, causing sinusitis in an immunocompetent patient.

Mini-exon epitope tagging for analysis of the protein coding potential of genomic sequence

A novel approach to gene discovery and analysis is described. A small exon flanked by consensus 3' and 5' splice sites was synthesized. The exon contains open reading frames encoding 43 amino acid peptides. There are no stop codons in any of the three reading frames, and each reading frame contains an epitope recognized by the same monoclonal antibody. The exon can be inserted into the introns of genes, and the resulting small peptide will be incorporated into the protein encoded by the host gene, regardless of the class of intron. The protein can then be recognized by the antibody, permitting functional studies.

CD29 expression on CD4+ gingival lymphocytes supports migration of activated memory T lymphocytes to diseased periodontal tissue

The cell surface phenotypes of CD+ cells extracted from inflammatory periodontal disease tissues were analyzed using two- and three-color immunofluorescence and flow cytometry. Cells extracted from both adult periodontal and localized juvenile periodontitis lesions showed a depressed CD4/CD8 ratio (1.0 +/- 0.1 adult periodontitis and 1.1 +/- 0.1 localized juvenile periodontitis) compared with cells recovered from normal/marginal gingivitis tissue (1.8 +/- 0.2) or with normal peripheral blood cells (2.1 +/- 0.1) or periodontal disease blood cells (2.1 +/- 0.1 and 1.7 +/- 0.1 for adult periodontitis and juvenile periodontitis, respectively). The monoclonal antibodies anti-2H4 and anti-4B4 were used to identify the CD45RA and CD29 antigens respectively on CD4+ T cells from the periodontal disease lesions. In peripheral blood. CD29+ cells accounted for 66-77% of the CD4+ population, and CD45RA+ cells accounted for 22-27% of the CD4+ subset. No differences in expression were found between peripheral blood lymphocytes from normal subjects and from periodontal disease patients. Two-color analyses of lymphocytes from periodontal diseased tissues showed that 87-89% of the CD4+ population were CD29+ and that 70-79% of the CD4+ cells were CD45RA+. Normal tissues contained significantly fewer CD4+CD29+ cells (56 +/- 4%) and CD4+CD45RA+ cells (40 +/- 4%) on average, and few, if any double-labelled cells could be accounted for. These data implied that a significant percentage of the CD4+ cells from the diseased tissues were both CD29+ and CD45RA+ and that these populations are found in quite different proportions in diseased periodontal tissue than in peripheral blood or nondiseased tissue. In further analyses using three-color cytometry the mean percentage of CD4+ CD29+ CD45RA+ lymphocytes extracted from periodontal disease lesions was 43 +/- 9% of the CD4+ population. These results suggest that CD4+ T lymphocytes in periodontal disease not only demonstrate varying levels of maturity but also that the accumulation of CD4+ T cells within the periodontal tissues may be a result of increased adhesion and transendothelial migration.

Acute mesenteric vein thrombosis and pancreatitis. A rare association

This article presents a case of acute mesenteric vein thrombosis with small bowel infarction associated with pancreatitis. Although a rare occurrence, the authors suggest this diagnosis should be considered as a possible complication of pancreatic inflammation.

Functional screening of 2 Mb of human chromosome 21q22.2 in transgenic mice implicates minibrain in learning defects associated with Down syndrome

Using Down syndrome as a model for complex trait analysis, we sought to identify loci from chromosome 21q22.2 which, when present in an extra dose, contribute to learning abnormalities. We generated low-copy-number transgenic mice, containing four different yeast artificial chromosomes (YACs) that together cover approximately 2 megabases (Mb) of contiguous DNA from 21q22.2. We subjected independent lines derived from each of these YAC transgenes to a series of behavioural and learning assays. Two of the four YACs caused defects in learning and memory in the transgenic animals, while the other two YACs had no effect. The most severe defects were caused by a 570-kb YAC; the interval responsible for these defects was narrowed to a 180-kb critical region as a consequence of YAC fragmentation. This region contains the human homologue of a Drosophila gene, minibrain, and strongly implicates it in learning defects associated with Down syndrome.

The vibrator mutation causes neurodegeneration via reduced expression of PITP alpha: positional complementation cloning and extragenic suppression

The mouse vibrator mutation causes an early-onset progressive action tremor, degeneration of brain stem and spinal cord neurons, and juvenile death. We cloned the vibrator mutation using an in vivo positional complementation approach and complete resequencing of the resulting 76 kb critical region from vibrator and its parental chromosome. The mutation is an intracisternal A particle retroposon insertion in intron 4 of the phosphatidylinositol transfer protein alpha gene, causing a 5-fold reduction in RNA and protein levels. Expression of neurofilament light chain is also reduced in vibrator, suggesting one signaling pathway that may underlie vibrator pathology. The vibrator phenotype is suppressed in one intercross. We performed a complete genome scan and mapped a major suppressor locus (Mvb-1) to proximal chromosome 19.

Evaluation of a terrestrial food chain model for estimating foodstuff concentrations of PCDD/Fs

A terrestrial food chain model designed to predict foodstuff concentrations of PCDD/Fs from observed air and soil concentrations is described, and its efficacy evaluated by comparison of predicted and observed concentrations in specific foodstuffs and estimates of daily human exposure. The limitations of the model are discussed and future research requirements identified.

Biomechanical alterations in normal skin and hypertrophic scar after thermal injury

Functional recovery after burn injury can be significantly limited by scar contraction and contracture. Mechanisms to explain these problems are not well described. Surface (shear) waves were generated in normal skin and hypertrophic burn scar with a newly described device. The velocity of propagation was used to examine biomechanical changes after burn injury. Shear wave velocity was markedly higher in scar and slightly higher in injured tissue without obvious scarring, verifying increased skin stiffness. Normal skin anisotrophy was exaggerated in scar tissue and not seen in the uninjured skin adjacent to hypertrophic scar. This result suggests the reorganization of normal tissue attempts to compensate for scar contraction. Measurements of shear wave velocity objectively document changes in skin properties that affect the recovery from thermal injury. Use of this or alternate technologies may increase understanding of postburn skin dysfunction, improving our ability to treat such patients.

Distribution, elimination, and residues of [14C]clenbuterol HCl in Holstein calves

Clenbuterol HCl is a beta-adrenergic agonist that has been used illegally in Europe and the United States by some livestock producers to increase carcass leanness. The objectives of this study were to determine the metabolic disposition, distribution of radioactivity, and the concentrations of parent clenbuterol in tissues after a single oral dose of [14C] clenbuterol HCl in calves. [14C]Clenbuterol HCl (1.59 microCi/mg, 3 mg/kg BW) was administered to a 74- and a 96-kg Holstein bull calf as a single oral dose. Blood samples were taken at 1, 3, 6, 12, 24, 36, and 48 h after dosing; urine and feces were collected separately and placed into respective pools from 0 to 6, 6 to 12, 12 to 24, 24 to 36, and 36 to 48 h after dosing. At 48 h after dosing, calves were anesthetized and exsanguinated, and visceral organs, bile, eyes, brain, skeletal muscle, skin, adipose tissue, and the remainder of the carcass were collected. Tissues were processed by coarse grinding through a Hobart grinder, followed by homogenization on dry ice. Eyes were dissected and the various tissues and excreta were assayed for total radiocarbon content by combustion analysis and(or) liquid scintillation counting. Parent clenbuterol was measured in selected tissues by HPLC after solvent extraction. Urinary, fecal, and carcass radioactivity averaged 41.5 +/- 8.1, 2.4 +/- .4, and 52.3 +/- 8.7% of the dose, respectively (mean +/- SD.). Average total recovery of radiocarbon was 96.2 +/- .4%. Radioactive residues present in carcasses averaged (ppm; mean +/- SD.): blood, .6 +/- .2; heart, 1.4 +/- .0; lungs, 8.4 +/- 1.7; spleen, 2.6 +/- .3; liver, 5.0 +/- .4; kidney, 5.9 +/- .0; brain, 1.9 +/- .4; adipose tissue, 1.1 +/- .2; rumen, reticulum, omasum, abomasum, 2.3 +/- .4; small intestine, 3.2 +/- .3; large intestine, 4.0 +/- .4; skeletal muscle, 1.0 +/- .2; bile, 12.5 +/- 4.0; white skin, .7 +/- .1; black skin, 4.0 +/- .7; remainder of the carcass, 1.0 +/- .2. Ocular residues were as follows: aqueous humor, 6.3 +/- 1.2; cornea, 13.5 +/- 8.6; iris, 255.8 +/- 167.0; lens, 2.3 +/- 1.5; vitreous humor, 2.2 +/- .4; retina/choroid, 84.5 +/- 34.1; sclera, 11.1 +/- 2.1. Mean concentrations of parent clenbuterol in tissues were (ppm; mean +/- SD): lung, 6.8 +/- .9; liver, 2.2 +/- .5; kidney, 3.7 +/- .5; and heart, .9 +/- .1. Parent clenbuterol represented from 43.9% of the total residue in liver to 81.2% of the total residue in lung.

Differential regulation and function of CD73, a glycosyl-phosphatidylinositol-linked 70-kD adhesion molecule, on lymphocytes and endothelial cells

CD73, otherwise known as ecto-5'-nucleotidase, is a glycosyl-phosphatidylinositol-linked 70-kD molecule expressed on different cell types, including vascular endothelial cells (EC) and certain subtypes of lymphocytes. There is strong evidence for lymphocyte CD73 having a role in several immunological phenomena such as lymphocyte activation, proliferation, and adhesion to endothelium, but the physiological role of CD73 in other cell types is less clear. To compare the biological characteristics of CD73 in different cell types, we have studied the structure, function, and surface modulation of CD73 on lymphocytes and EC. CD73 molecules on lymphocytes are shed from the cell surface as a consequence of triggering with an anti-CD73 mAb, mimicking ligand binding. In contrast, triggering of endothelial CD73 does not have any effect on its expression. Lymphocyte CD73 is susceptible to phosphatidylinositol phospholipase, whereas only a small portion of CD73 on EC could be removed by this enzyme. Furthermore, CD73 on EC was unable to deliver a tyrosine phosphorylation inducing signal upon mAb triggering, whereas triggering of lymphocyte CD73 can induce tyrosine phosphorylation. Despite the functional differences, CD73 molecules on lymphocytes and EC were practically identical structurally, when studied at the protein, mRNA, and cDNA level. Thus, CD73 is an interesting example of a molecule which lacks structural variants but yet has a wide diversity of biological functions. We suggest that the ligand-induced shedding of lymphocyte CD73 represents an important and novel means of controlling lymphocyte-EC interactions.

Bioaccumulation factors (BAFs) and biota to sediment accumulation factors (BSAFs) for PCBs in pike and eels

"Freely-dissolved" aqueous concentrations of 9 trichlorothrough heptachlorobiphenyls are reported, alongside those in sediments and fish from the R. Severn. For most congeners, BSAFs and lipid-normalised BAFs for pike exceed those for eels. Whilst R. Severn BSAFs are comparable with those for L. Ontario trout and New Bedford Harbour flounder, R. Severn BAFs are 1-2 orders of magnitude lower. This discrepancy may be due to inter-species variability, as well as inter-laboratory differences between operational definitions of "freely-dissolved" aqueous PCB, underlining that the same operational definition must be employed if R. Severn BAFs are extrapolated elsewhere. For eels, correlation of Log K(ow) with Log BAF is better (R(2) = 0.66) than with BSAF (R(2) = 0.13), whilst similar correlation coefficients (R(2) = 0.81 and 0.82) were observed for pike. When Log K(ow) is plotted against BSAF and Log BAF for both species combined, better correlation is observed for Log BAF (R(2) = 0.65), than BSAF (R(2) = 0.36). For both species combined, the observed relationship between Log BAF and Log K(ow) for trichloro-through heptachlorobiphenyls is: Log BAF = 0.96 * Log K(ow) -0.24.

IL-1 beta convertase (ICE) does not play a requisite role in apoptosis induced in T lymphoblasts by Fas-dependent or Fas-independent CTL effector mechanisms

Both IL-1beta convertase (ICE) and other members of the ICE-like family of proteases have been reported to play a role in Fas-mediated apoptosis. Con A-stimulated T lymphoblasts generated from splenocytes isolated from ICE-deficient H-2b mice were found to be more susceptible than wild-type lymphoblasts to DNA fragmentation induced by H-2b-specific CTL derived from normal or Fas ligand-deficient gld/gld mice. Trinitrophenyl (TNP)-modified, H-2b target cell-specific CTL were generated from perforin-deficient mice and were found to induce DNA fragmentation only in target cells expressing functional Fas receptors. Similar rates of DNA fragmentation were induced in TNP-modified ICE -/- and ICE +/+ T lymphoblast targets by perforin -/- TNP-modified, H-2b target cell-specific CTL. In addition, anti-Fas Abs induced apoptosis in thymocytes, Con A-stimulated spleen T cells, LPS-stimulated spleen B cells, and thymocytes from ICE -/- mice. However, DNA fragmentation induced by either allospecific FasL-defective CTL, or by perforin-deficient, TNP-modified, H-2b target cell-specific CTL was prevented in ICE -/- target cells loaded by electroporation with Ac-DEVD-CHO, an inhibitor of CPP32 and related ICE family proteases. These findings indicate that ICE does not play a requisite role in Fas-dependent or Fas-independent mechanisms of apoptosis induced in peripheral T lymphoblasts by CTL. However, both major pathways of CTL-induced apoptosis appear to be dependent on the enzymatic activity of other ICE family proteases.

IL-1 beta convertase (ICE) does not play a requisite role in apoptosis induced in T lymphoblasts by Fas-dependent or Fas-independent CTL effector mechanisms

Both IL-1beta convertase (ICE) and other members of the ICE-like family of proteases have been reported to play a role in Fas-mediated apoptosis. Con A-stimulated T lymphoblasts generated from splenocytes isolated from ICE-deficient H-2b mice were found to be more susceptible than wild-type lymphoblasts to DNA fragmentation induced by H-2b-specific CTL derived from normal or Fas ligand-deficient gld/gld mice. Trinitrophenyl (TNP)-modified, H-2b target cell-specific CTL were generated from perforin-deficient mice and were found to induce DNA fragmentation only in target cells expressing functional Fas receptors. Similar rates of DNA fragmentation were induced in TNP-modified ICE -/- and ICE +/+ T lymphoblast targets by perforin -/- TNP-modified, H-2b target cell-specific CTL. In addition, anti-Fas Abs induced apoptosis in thymocytes, Con A-stimulated spleen T cells, LPS-stimulated spleen B cells, and thymocytes from ICE -/- mice. However, DNA fragmentation induced by either allospecific FasL-defective CTL, or by perforin-deficient, TNP-modified, H-2b target cell-specific CTL was prevented in ICE -/- target cells loaded by electroporation with Ac-DEVD-CHO, an inhibitor of CPP32 and related ICE family proteases. These findings indicate that ICE does not play a requisite role in Fas-dependent or Fas-independent mechanisms of apoptosis induced in peripheral T lymphoblasts by CTL. However, both major pathways of CTL-induced apoptosis appear to be dependent on the enzymatic activity of other ICE family proteases.

Human huntingtin derived from YAC transgenes compensates for loss of murine huntingtin by rescue of the embryonic lethal phenotype

Huntington disease (HD) is caused by expansion of a CAG trinucleotide repeat in exon 1 of a novel gene. The HD protein (huntingtin) plays a critical role in early embryonic development since homozygous targeted disruption of the murine HD gene results in embryonic lethality by day 7.5. To rescue this phenotype by transgene based huntingtin expression it is therefore essential to express the protein early enough in development in the appropriate cells. Since YAC based transgenes are known to be regulated in an appropriate temporal and tissue-specific manner, we sought to rescue the embryonic lethality by breeding YAC transgenic mice expressing human huntingtin with mice heterozygous for the targeted disruption. We generated viable offspring homozygous for the disrupted murine HD gene but expressing human huntingtin derived from the YAC. This result clearly shows that YAC transgene based expression of huntingtin occurs prior to 7.5 days gestation. Additionally, we show that human huntingtin expression in YAC transgenic mice follows an identical tissue distribution and subcellular localisation pattern as that of the murine endogenous protein and that expression levels of 2-3 times endogenous can be achieved. This shows that human huntingtin under the influence of its native promoter, despite differences to the murine protein, is functional in a murine background and can compensate for loss of the murine protein. These results show that YAC transgenic approaches are a particularly promising route to producing an animal model for disorders associated with CAG expansion.

Functional roles for granzymes in murine epidermal gamma(delta) T-cell-mediated killing of tumor targets

Granzymes, a family of serine proteases contained in cytoplasmic granules of cytotoxic T lymphocytes and natural killer cells, play a critical role in killing tumor targets by triggering rapid breakdown of DNA and subsequent apoptosis. We have reported previously that dendritic epidermal T cells, which are skin-specific members of the tissue-type gamma(delta) T-cell family in mice, are capable of killing selected tumor cell lines. Here we report that short-term cultured dendritic epidermal T-cell lines contain significant N-alpha-benzyloxycarbonyl-L-Lys-thiobenzyl esterase activity, produce granzyme A protein, and express constitutively mRNA for granzymes A and B. Messenger RNA expression for granzyme B was also confirmed in freshly procured Thy-1+ epidermal cells (i.e., dendritic epidermal T cells). Finally, preincubation of dendritic epidermal T cell lines with a granzyme inhibitor, dichloroisocoumarin, but not with a cysteine protease inhibitor, E-64, abrogated completely their capacity to trigger DNA breakdown in YAC-1 target cells. These results reinforce the concept that dendritic epidermal T cells represent skin-resident killer cells that share several functional properties with conventional killer leukocytes, thereby playing a local immunosurveillance role against tumor development.

Experimental immunization of rats with a Streptococcus mutans 59-kilodalton glucan-binding protein protects against dental caries

Glucan-binding proteins (GBPs) are theoretically important in the molecular pathogenesis of dental caries caused by Streptococcus mutans. The present study evaluated the ability of antibody induced by the S. mutans 59-kDa GBP (GBP59) to affect dental caries caused by experimental infection with S. mutans in a rodent model. Groups of 20-day-old rats were injected twice at 9-day intervals subcutaneously in the salivary gland vicinity with GBP59, glucosyltransferase (GTF), or phosphate-buffered saline (sham injection), each incorporated in an adjuvant. Two weeks after the second injection, GBP59- and GTF-injected rats contained significant levels of salivary immunoglobulin A and serum immunoglobulin G antibody to the respective injected antigens. However, cross-reacting antibody to S. mutans GTF or GBP59 was not induced by the respective antigen. Rats were then orally infected with S. mutans. After 71 days of infection, GBP59- and GTF-injected groups had smaller numbers of S. mutans on their molar surfaces, compared with the sham-injected infected group. Total, sulcal, and smooth-surface molar caries in the GBP59- and GTF-immunized S. mutans-infected groups were each significantly lower (P < or = 0.003) than the respective measures of caries in the sham injected infected group. The results of this investigation demonstrate that immunization with S. mutans GBP59 induces an immune response in rats that can interfere with the accumulation of S. mutans and can reduce the level of dental caries caused by this cariogenic streptococcus. Furthermore, the protective immunity induced by either GBP59 or GTF appears to result from antibodies to independent epitopes since these two S. mutans components do not have a close antigenic relationship.

Involvement of spinal cholecystokininB receptors in mediating neurotensin hyperalgesia from the medullary nucleus raphe magnus in the rat

Neurotensin microinjection into the medullary nucleus raphe magnus (RMg) has been shown to both inhibit and facilitate the spinal nociceptive tail-flick reflex in a dose-dependent manner. Our study was designed to determine a potential involvement of spinal cholecystokinin octapeptide (CCK) in mediating neurotensin hyperalgesia from the RMg. Microinjection of neurotensin (50 ng) into the RMg of awake rats produced a facilitation of the tail-flick reflex that was completely inhibited by intrathecal (i.t.) administration of the nonselective CCK receptor antagonist proglumide (100 ng). Conversely, injection of a greater dose of neurotensin (5 micrograms) into the RMg produced an inhibition of the tail-flick reflex that was enhanced by i.t. proglumide. Intrathecal administration of the selective CCKB receptor antagonist L-365260 dose-dependently inhibited neurotensin hyperalgesia from the RMg (ID50 = 0.42 ng) at doses approximately 1000-fold less than that observed with the selective CCKA receptor antagonist devazepide (ID50 = 646 ng). Injection of CCK alone i.t. produced a biphasic response on the tail-flick reflex as lesser doses (0.1-0.3 ng) inhibited the reflex although greater doses (30-100 ng) facilitated it. Similar to supraspinal neurotensin hyperalgesia, the hyperalgesia observed with i.t. CCK (30 ng) was inhibited by i.t. L-365260 (ID50 = 0.59 ng) at doses approximately 1000-fold less than that observed with i.t. devazepide (ID50 = 630 ng). These data indicate that spinal CCK can both inhibit and facilitate spinal nociceptive responses. The facilitation of nociception observed with spinal CCK appears to involve CCKB receptors, which is consistent with the data in our study suggesting that spinal CCKB receptors mediate neurotensin hyperalgesia from the RMg via descending neuronal projections.

Outcomes research: a primer for plastic surgeons

The growing emphasis on cost-effectiveness in the United States health care industry has highlighted the need for comprehensive outcomes research in a variety of medical specialties. Currently, there is a relative paucity of reliable data characterizing the long-term results of many medical and surgical treatments. This shortage of outcomes research is particularly acute within plastic surgery where the benefits of treatment are often intangible and notoriously difficult to measure. In evaluating the effectiveness of medical treatment, conventional clinical research has focused primarily on morbidity and mortality as the outcomes of interest. In contrast, current outcome studies assess the results of interventions from the patient's perspective, measuring the impact of medical care on physical functioning, well-being, and quality of life. The resulting data can assist consumers, providers, and payers in making more appropriate health care decisions. As the outcomes movement has matured, it has evolved into two major areas of study: effectiveness research that evaluates the relationships between specific medical interventions and outcomes of care, and quality assessment that seeks to provide the best outcomes at the most reasonable costs. This review details the origins and trends of current outcomes research, examining the implications of this movement for plastic surgery. The growing impact of outcomes data on treatment guideline formulation in both the public and private sectors is also described. Finally, a brief review of outcomes study design, including definition of variables and selection of instruments, is presented.

Enhancement of wound repair with a topically applied nitric oxide-releasing polymer

Nitric oxide is an important cytotoxic agent for host defense which also regulates gene expression, signal transduction, and vasodilation. In normal wounds, nitric oxide synthesis and metabolism are significantly increased during inflammation and tissue remodeling. However, nitric oxide production is suppressed in wounds where healing is impaired by diabetes or steroid-treatment. Topical delivery of nitric oxide in therapeutic amounts may alleviate this deficiency and thereby enhance wound repair. Consequently, we developed polyethyleneimine cellulose NONOate polymer, a nonsoluble, nontoxic, polymer-based NONOate--one of a new class of compounds that spontaneously release nitric oxide in a controlled fashion in aqueous media. Polyethyleneimine cellulose NONOate polymer was synthesized from polyethyleneimine cellulose to provide extended nitric oxide release with a half-life of 16 hours. Polyethyleneimine cellulose NONOate polymer or a control polymer was applied topically on full-thickness dermal wounds of rats at the time of wounding and days 3, 7, 10, 14, 17, and 21. Nitric oxide delivery was determined indirectly by measuring urinary nitrate. The first two polyethyleneimine cellulose NONOate polymer applications increased urinary nitrate output twofold to fourfold, whereas urinary nitrate output of control rats did not significantly increase. Nitrate output in polyethyleneimine cellulose NONOate polymer-treated rats was elevated compared with controls after each application, although this was attenuated in later applications. Rate of wound closure was measured with computer-based video imaging. Polyethyleneimine cellulose NONOate polymer-treated wounds were significantly smaller (p < 0.05) on days 7, 10, and 17 relative to controls, based on percentage of wound open relative to initial wound area. In a second experiment, telemetry-implanted rats were wounded to detect potential hypotensive effects as a result of polyethyleneimine cellulose NONOate polymer application. Topical polyethyleneimine cellulose NONOate polymer application to wounds showed no prolonged hypotensive effects, in contrast to a soluble NONOate which suppressed systolic blood pressure for over 6 hours. These results show that a nonsoluble, polymeric NONOate can provide topical nitric oxide delivery to wounds in a controlled manner, which may enhance wound healing. Further studies are in progress with other promising NONOate candidates to establish dose-response effects and therapeutic limits of exogenous nitric oxide release in impaired wound models.

A non-invasive, three-dimensional, diagnostic laser imaging system for accurate wound analysis

A PC-based laser imaging system has been developed that can accurately image and analyse three-dimensional (3D) surfaces in healing wound tissue. The device consists of a laser diode and sensor mounted to a motorized, bi-directional, X-Y table. The laser measures the distance to the wound surface as the X-Y table moves over the wound. The laser beam diameter is 1 x 2 mm and can measure distances as small as 8 microns. The distance information from the laser is used to produce the 3D image and to calculate the volume of the wound. The accuracy of this device is demonstrated by measuring rubber model wounds of 0.5, 1 and 2 ml. The per cent error for the 0.5 and 1 ml model wounds was less than 1 per cent and approximately 4 per cent for the 2 ml model. Studies were done in which full-thickness wounds were made on rats and monitored over a two week period. The rats were scanned five times during this period and the wound area and volumes calculated. The laser measurements are compared to measurements using saline and wound thickness multiplied by wound area.

Long-term results with the Kasai operation for biliary atresia

OBJECTIVE

To evaluate long-term outcome in a series of children with biliary results atresia treated by portoenterostomy.

DESIGN

Case series of consecutive infants with biliary atresia with 10-year follow-up. Data were obtained by retrospective chart review or phone interview.

SETTING

A tertiary academic medical center and regional children's hospital.

PATIENTS

A consecutive series of 104 infants diagnosed with biliary atresia more than 10 years ago were evaluated. Eighty-nine had totally obliterated extrahepatic ducts, 4 had proximal hilar cysts (correctable type), and 11 had patency of the gallbladder and distal common duct.

INTERVENTIONS

Ninety-eight patients underwent biliary reconstruction and 6 had exploration only. Seventy-four infants underwent reconstruction using a Rouxen-Y with exteriorization. The 11 infants with distal patency underwent a portocholecystostomy ("gallbladder Kasai"). The remainder had various modifications of the Kasai operation.

MAIN OUTCOME MEASURES

Survival, liver function, complications, growth, and development.

RESULTS

The 6 patients who did not have a portoenterostomy died. Of the 98 who had a reconstruction, 63 died (mean age at death, 27 months; median, 13.4 months), 10 following liver transplantation. Twelve of the 35 survivors ultimately required liver transplants. Twenty-three children are alive more than 10 years after portoenterostomy without the need for transplantation. Two thirds have experienced some manifestation of portal hypertension (ie, variceal bleeding, hypersplenism, ascites). Nineteen patients (79%) are anicteric with normal liver synthetic function and are in an age-appropriate school grade or working and living independently.

CONCLUSIONS

We found that surgical correction of biliary atresia offers long-term survival for about one quarter of patients, provides palliation until liver transplantation becomes necessary, and if surgical correction is not feasible, biliary atresia is uniformly fatal. The outlook is good for those children who survived more than 10 years and justifies continued attempts to establish bile flow in infants with biliary atresia.

Comparison of critical speed determined from track running and treadmill tests in elite runners

The purpose of this study was to compare critical speed determined from a field test of maximal effort runs between 3 and 15 min on a running track and a laboratory test of high-speed runs on a treadmill with a 10-km criterion performance. Nine highly trained male runners (VO ++(2max) 67.7 +/- 4.1 ml*kg*min(-1)) participated in the study. Critical speed was determined from three maximal runs (907, 2267.5, and 4081.5 m) on a 453.5-m indoor running track and from three high speed runs on a treadmill. The treadmill speeds were individualized so that exhaustion was reached in approximately 3, 7, and 13 min. All subjects participated in a 10-km cross-country race (measured distance 9.8 km) on a flat and dry course. Track critical speed (293 m*min(-1)) was correlated (r = 0.92, P < 0.001) with race speed (293 m*min(-1)), whereas treadmill critical speed (300 m*min(-1)) had the same correlation but over predicted race performance. It was concluded that although both tests were correlated with 9.8-km race performance, track-determined critical speed was easy to administer with highly trained runners and was very similar to 10-km race speed.

Diagnosis and management of diving accidents

Humans experience significant physiological stresses while diving, which can result in disease on occasion. With the increasing popularity of sports diving, it is critical that both physicians and divers be aware of the spectrum of illness associated with diving. An overview of common diving-related disorders is presented. After a brief discussion of relevant physics principles, the clinical presentation of ear and sinus squeeze is covered along with preventive strategies and treatment. This is followed by a discussion of the pathophysiology, clinical settings, and manifestations of pulmonary barotrauma along with a review of the pathophysiology and presentation of decompression illness. Initial emergency measures and referral procedures for decompression related disorders are addressed. A brief discussion of recompression therapy is included.

Nitric oxide-releasing polymers containing the [N(O)NO]- group

Ions of structure X[N(O)NO]- display broad-spectrum pharmacological activity that correlates with the rate and extent of their spontaneous, first-order decomposition to nitric oxide when dissolved. We report incorporation of this functional group into polymeric matrices that can be used for altering the time course of nitric oxide release and/or targeting it to tissues with which the polymers are in physical contact. Structural types prepared include those in which the [N(O)NO]- group is attached to heteroatoms in low molecular weight species that are noncovalently distributed throughout the polymeric matrix, in groupings pendant to the polymer backbone, and in the polymer backbone itself. They range in physical form from films that can be coated onto other surfaces to microspheres, gels, powders, and moldable resins. Chemiluminescence measurements confirm that polymers to which the [N(O)NO]- group is attached can serve as localized sources of nitric oxide, with one prototype providing sustained NO release for 5 weeks in pH 7.4 buffer at 37 degrees C. The latter composition, a cross-linked poly-(ethylenimine) that had been exposed to NO, inhibited the in vitro proliferation of rat aorta smooth muscle cells when added as a powder to the culture medium and showed potent antiplatelet activity when coated on a normally thrombogenic vascular graft situated in an arteriovenous shunt in a baboon's circulatory system. The results suggest that polymers containing the [N(O)NO]- functional group may hold considerable promise for a variety of biomedical applications in which local delivery of NO is desired.

Erythropoietin does not demonstrate circadian rhythm in healthy men

The hormone erythropoietin (Epo) produced in the kidneys in response to hypoxia stimulates the production of red blood cells. We measured serum Epo levels in 26 healthy men over a 24-h period to determine whether Epo is secreted according to a circadian rhythm. Samples were collected every 2-4 h, and Epo was measured by using a radioimmunoassay (INCSTAR Epo-trac). To determine whether blood collection had any effect on Epo production, one-half of the subjects began the collection period in the morning and the other half in the evening. Exercise and the use of prostaglandin inhibitors were prohibited to eliminate fluctuations in Epo production in response to discrete stimuli. The daily Epo concentration for all subjects combined was 15.5 +/- 5.3 (SD) U/l. No significant circadian variation in serum Epo concentrations was observed in either group or when both groups were combined; however, a measure of individual variance was observed (mean deviation = 0.8 +/- 0.4 U/l).

TNF-alpha potentiates oxidant and reperfusion-induced endothelial cell injury

Pulmonary edema following reperfusion is a major clinical problem. Changes in endothelial cell shape induced by oxidant injury may account for immediate capillary leakage associated with reperfusion injury. In these experiments we examined the role of tumor necrosis factor-alpha (TNF-alpha) in acute endothelial cell injury following ischemia-reperfusion. Sprague-Dawley rats were treated with a neutralizing antisera directed against TNF-alpha prior to production of distal ischemia. These rats demonstrated a significant reduction (P < 0.05) in acute lung edema in response to 4 hr of ischemia and 30 min of reperfusion when compared to rats undergoing the same procedure without antisera treatment. An in vitro model was developed to determine if TNF-alpha had a direct effect on endothelial cell response to ischemia-reperfusion. The effects of TNF-alpha and oxidant stress on the integrity of cultured endothelial cell monolayers was measured. Rat pulmonary artery endothelial cell monolayers reacted in vitro to oxidant stress by an increase in permeability. The cells changed shape and an increase in diffusion of 125I-albumin across cell monolayers resulted when these cells were exposed to 50 microM hydrogen peroxide (H2O2) or plasma from the ischemic hind limb of a Sprague-Dawley rat (50 microliters/ml). Pretreatment of cultured cells with low levels of recombinant mouse TNF-alpha significantly affected both the cell shape change and the increase in permeability (P < 0.05). Increased permeability of cell monolayers in vitro was not due to cell lysis as determined by media lactate dehydrogenase levels. The effect appeared to be due to cellular rounding and contraction seen using video time lapse microscopy. These data suggest a direct effect of TNF-alpha on endothelial cells, whereby the cells are rendered more susceptible to oxidant injury accompanying reperfusion.

Comparison of a rapid hepatitis B immunization schedule to the standard schedule for adults

We report a prospective, randomized, single-blinded trial comparing immunogenicity of rapid (0, 1, and 2 months) versus standard schedule (0, 1, 6 months) hepatitis B vaccinations of healthy adults with recombinant hepatitis B vaccine (Engerix-B, 20 micrograms i.m.) (230 of 234) negative to hepatitis B were randomized and completed the study. Groups were similar in age, weight, race, and obesity rate, but the rapid schedule group had more women. Both groups reached > or = 100 mIU/mL at a similar rate, but a higher seroprotection rate at > or = 500 mIU/mL was reached by the standard schedule. No demographic variables influenced the effect of dose schedule on anti-hepatitis B titer. We conclude that rapid schedule vaccination gives a rate that is quicker than, and identical to, the rate of seroprotection of the standard schedule vaccination.

Biochemical and pharmacological characterization of multiple beta-endorphinergic antinociceptive systems in the rat periaqueductal gray

Based on the differential abilities of the opioid antagonists naltrexone and D-Phe-Cys-Tyr-D-Trp-Lys-Thr-Pen-Thr-NH2 (CTP) to antagonize the antinociceptive action of beta-endorphin and morphine in the rat periaqueducatal gray (PAG), three pharmacologically distinct mechanisms were determined to mediate the antinociceptive effect of beta-endorphin. Two of these mechanisms are unique to beta-endorphin, possess a high affinity for CTP and can be discriminated based on their differential sensitivity to naltrexone. The third mechanism displays characteristics common to that activated by morphine. The results of radioligand binding studies were consistent with these observations. [125I]-beta-Endorphin labeled a population of sites in the PAG which (compared to those labeled by [3H]morphine) displayed a significantly higher affinity for CTP. In addition, a naltrexone-insensitive binding component was identified in the [125I]-beta-endorphin, but not [3H]morphine assays. Furthermore, comparable competitor affinities were determined across assays, suggesting an interaction of the radioligands with common PAG sites. A naltrexone-insensitive component to beta-endorphin antinociception also was identified in studies which evaluated the ability of the antagonist to shift the beta-endorphin dose-response curve. Interestingly, the ability of low doses of CTP and naltrexone to inhibit increasing doses of beta-endorphin was described by a U-shaped dose effect curve. The response to low and high, but not intermediate, doses of beta-endorphin were antagonized by picomole doses of both antagonists. As there was no evidence for allosteric interactions between [125I]-beta-endorphin binding sites in the PAG, it appears that beta-endorphin also may activate pain facilitory mechanisms which counterbalance its overall antinociceptive effect.

Diagnosis of silicone gel breast implant rupture by ultrasonography

To prospectively evaluate the efficacy of ultrasonography in the diagnosis of ruptured silicone gel breast implants, 98 patients (192 implants) underwent preoperative breast ultrasonography prior to silicone gel breast implant removal. The prevalence of implant rupture confirmed at surgery in this group of patients was 62 of the 192 implants (32 percent). Of the 60 implants diagnosed as ruptured by ultrasonography, 46 were confirmed as having visible defects at surgery (true positive) for a positive predictive value of 77 percent. Of the 132 implants diagnosed as intact by ultrasonography, 116 were confirmed as intact at surgery (true negative) for a negative predictive value of 88 percent. Overall, the sensitivity of ultrasonography for implant rupture was 74 percent, and the specificity was 89 percent. These findings demonstrate that ultrasonography is an effective imaging modality for the diagnosis of silicone gel breast implant rupture. Compared with mammography, ultrasonography appears to offer superior sensitivity and specificity without radiation exposure or discomfort. Although magnetic resonance imaging has shown considerable promise in the diagnosis of implant rupture, ultrasonography provides comparable sensitivity at a fraction of MRI's cost.

Identification of beta-glucuronidase-resistant diastereomeric glucuronides of 3-hydroxy-3-methyloxindole formed during 3-methylindole metabolism in goats

Goats were jugularly infused with the pneumotoxin 3-methylindole (3MI; 15 mg/kg, 0.5 microCi/kg) dissolved in cremophor-EL to characterize the urinary metabolites of 3MI in a ruminant specie. Urine was collected for 36 hr after the beginning of a 2-hr infusion period, and 3MI metabolites were purified using reversed-phase HPLC. Goats excreted 3MI as at least 11 distinct metabolites. Metabolites were characterized using a combination of UV spectroscopy, 1H- and 13C-NMR spectroscopy, and negative-ion FAB/MS. Two of the metabolites (E1 and E2), representing approximately 30% of the urinary radioactivity, were unambiguously identified as diastereomeric glucuronides of 3-hydroxy-3-methyloxindole [HMOI; 3-(beta-D-glucosiduronic acid)-3-methyloxindole]. Glucuronide conjugates were investigated using enzymatic and chemical hydrolysis. These ethereal glucuronides were unique in that they were not readily hydrolyzable with bovine beta-glucuronidase, although one of the diastereomers was hydrolyzed sparingly by beta-glucuronidase from Helix pomatia. Treatment of the glucuronides with 6 M HCI for a 2-hr period liberated unconjugated HMOI. Treatment of each diastereomer with dilute acid (pH 3) or dilute alkali (pH 10) was ineffective at hydrolyzing the conjugates. Goats form HMOI from 3MI and extensively glucuronidate the metabolite before excreting it, as opposed to mice that do not conjugate HMOI before excretion. These ethereal glucuronic acid conjugates seem to be unique in that they are essentially resistant to beta-glucuronidase-catalyzed hydrolysis.