Novel selective compounds for the investigation of imidazoline receptors

Over several years our group has sought to synthesize and identify selective ligands for imidazoline (I) receptors, in particular the I2 binding site. As a consequence, [3H]2-(2-benzofuranyl)-2-imidazoline (2BFI) has proved extremely useful for binding and autoradiographic studies. More recently we have synthesized a BU series of compounds and examined these for their affinities for both I1 and I2 binding sites. BU224 (2-(4,5-dihydroimidaz-2-yl)-quinoline) shows high affinity for I2 receptors with a Ki of 2.1 nM. BU226 (2-(4,5-dihydroimidaz-2-yl)-isoquinoline) demonstrated slightly higher affinity (Ki 1.4 nM) for I2 receptors, but overall BU224 displayed greater selectivity for I2 over I1 receptors (832-fold) than BU226 (380-fold). Both compounds showed low (microM) affinity for alpha 2-adrenoceptors. Given BU224's ability to cross the blood brain barrier, we predict that its in vivo effects are likely to be mediated via I2 receptors. Brain dialysis revealed BU224 to dose dependently (0-20 mg/kg i.p.) elevate basal noradrenaline in rat frontal cortex and basal dopamine in striatum. In a rat model of opiate withdrawal, behavioral studies showed that BU224 (10 mg/kg, s.c.) was able to reduce acute weight loss and diarrhea, but not the number of wet dog shakes associated with the withdrawal syndrome.

Histochemical and ultrastructural modification of mucosal mast cell granules in parasitized mice lacking the beta-chymase, mouse mast cell protease-1

The soluble beta-chymases mouse mast cell protease-1 (mMCP-1) and rat mast cell protease-II are predominantly expressed by intestinal mucosal mast cells (IMMCs) and may promote mucosal epithelial permeability when released during intestinal allergic hypersensitivity responses. To study the function of these chymases, we generated mice with a homozygous null mutation of the mMCP-1 gene and investigated their response to infection with the intestinal nematode Nippostrongylus brasiliensis. Whereas mMCP-2, -4, and -5 were transcribed normally, there was no transcription of the mMCP-1 gene in null (-/-) mice, nor was mature mMCP-1 protein detected in (-/-) jejunal mucosa. In contrast, levels of mMCP-1 in wild-type (+/+) jejunal mucosa increased 200- to 350-fold from 0.66 microg mMCP-1/g wet weight in uninfected mice to 129 and 229 microg/g wet weight on days 8 and 10 of infection, respectively. The kinetics of IMMC recruitment differed in -/- mice compared with +/+ controls on days 8 (P < 0.05) and 10 (P < 0.03) of infection. The IMMCs in infected -/- mice stained poorly, if at all, for esterase with naphthol AS-D chloroacetate compared with the intense staining observed in +/+ controls. Ultrastructurally, the prominent crystal intragranular structures that are found in intraepithelial +/+ IMMCs were absent from -/- IMMCs. These data show that disruption of the mMCP-1 gene leads to profound histochemical and ultrastructural changes in IMMC granules.

Updated measurements from CREAM & CREDO & implications for environment & shielding models

Flight data obtained between 1995 and 1997 from the Cosmic Radiation Environment Monitors CREAM & CREDO carried on UoSat-3, Space Shuttle, STRV-1a (Space Technology Research Vehicle) and APEX (Advanced Photovoltaic and Electronics Experiment Spacecraft) have been added to the dataset affording coverage since 1990. The modulation of cosmic rays and evolution of the South Atlantic Anomaly are observed, the former comprising a factor three increase at high latitudes and the latter a general increase accompanied by a westward drift. Comparison of particle fluxes and linear energy transfer spectra is made with improved environment & radiation transport calculations which account for shield distributions and secondary particles. While there is an encouraging convergence between predictions and observations, significant improvements are still required, particularly in the treatrnent of locally produced secondary particles.

Intrasound vibration in the early diagnosis of scaphoid fracture

A prospective trial was designed to assess the sensitivity and specificity of intrasound vibration for the early detection of scaphoid fracture. We replicated the method described by Finkenburg et al. (J Hand Surg 1993;18A:4-7) in an attempt to corroborate their results. We found the test to be 73% sensitive and 51% specific. Because the test was not 100% sensitive, as claimed by Finkenburg et al., we discontinued the use of this device in our hospital.

X-ray intensifying screen visible light detection meter

A light meter has been designed and built for the purpose of measuring the light emitted from an intensifying screen during x-ray irradiation. The meter uses a photodiode detector with a minimal drift amplification system. The meter repeatability was better than 0.5% and was found to be linear. A significant x-ray induced signal was recorded during measurement which needed to be subtracted from readings to deduce the intensification screen light output. The energy response of four screen types was subsequently measured.

Conservation of neutralizing determinants between the sporozoite surface antigens of Theileria annulata and Theileria parva

The sporozoite surface antigens SPAG-1 of Theileria annulata and p67 of Theileria parva are postulated to contain determinants necessary for host cell invasion and/or recognition and are both being considered as candidates for inclusion in subunit vaccines. Preliminary data suggest that these are related molecules. In this paper we describe the investigation of the relationship between these sporozoite antigens further by analysis of the immunological cross-reactivity using Mabs and sera raised against each antigen. The cross-reactions were examined by carrying out Western blots, IFA tests, and in vitro sporozoite neutralization assays. In addition, sequence comparison data which clearly establish that these surface antigens are encoded by related genes are presented. The regions of SPAG-1 identified as containing cross-reactive epitopes recognized by p67 antiserum correlated to regions of high predicted homology between p67 and SPAG-1, which are located at their respective N- and C-termini. Furthermore, p67 and SPAG-1 were found to contain cross-reactive determinants responsible for neutralization of sporozoite infectivity in vitro, and at least some of these were located in the C-termini of both molecules. The relevance of these findings to the possible roles for these molecules in host cell invasion is discussed.

The structure of the head-tail junction of the myosin molecule

An atomic model of the junction between the two heads and tail of a myosin molecule has been created by attaching a scallop regulatory domain to the end of each of the two alpha-helical strands of a model of the scallop alpha-helical coiled coil. The C-terminal alpha-helix of the heavy chain of each regulatory domain was superposed over the corresponding sequence in the coiled coil. In the structure created, the two heads lie alongside one another with their bases in contact but remarkably without steric clash. The principal interactions between the two heads are between the regulatory light chains and there are also head-tail interactions between each regulatory light chain and its heavy chain partner in the coiled coil. The invariant proline residues cause the heavy chains to flare to form the fork. The direction of the turn at the WQW sequence within the regulatory domain causes the long alpha-helix of the heavy chains within the head to continue the sense of the supercoil. With the bases of heads interacting, motion of the heads could still occur by a flexing of the coiled coil close to the heads and by a flexing and twisting of the long alpha-helices in the head. The model accounts for some of the conserved sequence features in myosins from different sources and provides a structural basis for understanding the head-head interactions in regulated myosin. Using the C alpha atoms of subfragment 1 we have also constructed a model with two complete heads. The clockwise curvature of the heads when the model is viewed end-on towards the tail accounts for the most common appearance of myosin molecules in electron micrographs. These models are predicated on the assumption that the entire heptad sequence of the heavy chains forms a coiled coil. Previous evidence from electron micrographs of myosin molecules that this was not the case can be explained by the foreshortening of the tail close to the heads.

The influence of age on the management of anal cancer

The standard treatment for anal cancer is combination chemo-radiotherapy. Management decisions such as radical chemotherapy, resective surgery for poor response or relapse are frequently modified by age-associated comorbid factors. Between 1980 and 1990, our regional cancer center serving a population of 1.8 million saw 78 patients with squamous carcinoma of the anus. We have compared patients who were younger than 65 years (n = 38) with those older than 65 years (n = 38). The mean +/- standard deviation age for the whole cohort was 65 +/- 12 years, with a ratio of 2 females to each male presenting. Fewer of the elderly age group had major surgery (26% vs. 42%) (p = 0.03), and fewer suffered no toxicity (42% vs. 26%) (p = 0.03). However, 61% of the under-65-year age group are alive disease-free vs. 26% of the elderly group (p = 0.03). Similarly, only 18% of the under-65-year group died with disease compared with 37% of the elderly group (b = 0.03). For the series as a whole, the crude mortality was 42%, with 27% dying of their disease. The stage distribution, and the amount of radiotherapy or chemotherapy administered was not age-specific, but younger patients had more surgery and suffered more toxicity, with a greater proportion remaining alive and disease-free, and fewer dying of their disease. These data suggest that a more aggressive multi-modality approach in the elderly may improve disease response and survival.

The value of endorectal ultrasonography in the follow-up of intracavitary radiation treated early rectal cancer

In selected patients with early rectal cancer, intracavitary radiation is a successful treatment. Endorectal ultrasound has proved an accurate method for staging and selecting such cancers for treatment. The value of endorectal ultrasound in the follow-up of patients with intracavitary radiation has not been previously assessed. Between 1989 and 1991, 30 patients treated at the Hamilton Regional Cancer Centre with intracavitary radiation were assessed by endorectal ultrasound. The mean age was 65 +/- 12 years with a range of 37-78 years. There were 17 males and 13 females. All patients were treated with curative intent. The dose of radiation administered was 8963 +/- 1506 cGy over 3.5 +/- 0.7 fractions. No patient received supplemental iridium implantation. Thirty-seven endorectal ultrasounds were carried out in 30 of the intracavitary radiation treated patients. Clinical findings (digital, sigmoidoscopic, and histology) were compared with the radiologist's interpretation of the endorectal ultrasounds. Using a 2 x 2 table accepting the clinical findings as the 'Gold Standard', the sensitivity of endorectal ultrasound was 71%, the specificity 61%, the positive predictive value 53%, the negative predictive value 78% with an overall accuracy of 75%. We conclude that endorectal ultrasound in the routine follow-up of patients treated with intracavitary radiotherapy for carcinoma of the rectum is questionable.

Polymorphism of SPAG-1, a candidate antigen for inclusion in a sub-unit vaccine against Theileria annulata

SPAG-1, a Theileria annulata sporozoite surface antigen, is a vaccine candidate. Data is presented, based on the clonal segregation of SPAG-1 associated RFLPs, showing that this antigen is encoded by a single copy gene. We have cloned and sequenced a full-length genomic copy of the SPAG-1 gene and a comparison of this with a previously published SPAG-1 cDNA sequence demonstrates a high degree of polymorphism. We infer that these sequences represent two distinct allelic SPAG-1 variants. The deduced polypeptides show an overall identity of 92% with the most variable stretch (60% identity) occurring towards the middle of the molecule. The N and C termini are more conserved with identities of 92% and 97% respectively. The elastin receptor ligand, VGVAPG, present 3 times in the protein sequence derived from the cDNA is not found in that deduced from the genomic copy. Evidence for 2 further SPAG-1 alleles was obtained from PCR based sequences using macroschizont clones containing different SPAG-1 associated RFLPs. In summary we have shown the existence of at least 4 highly polymorphic SPAG-1 alleles. The implications of such polymorphism between and within distinct geographical isolates for the development of a SPAG-1 based subunit vaccine is discussed.

Assessing selfcare status in quadriplegia: comparison of the quadriplegia index of function (QIF) and the functional independence measure (FIM)

The purpose of this study was to compare the quadriplegia index of function (QIF) to the functional independence measure (FIM) in assessing the daily performance of selfcare activities by individuals with cervical spinal cord injury. This study evaluated feeding, grooming and bathing activities in 22 C4-C7, Frankel A-D spinal cord injury patients between 3 and 12 months postinjury. The manual muscle test (MMT) was performed on 17 of these subjects during the same window of time as the QIF and the FIM. An upper extremity motor score (UEMS) was derived from the MMT. In order to relate motor power to functional ability, the UEMS was used as a measure of neurological function to test the hypothesis that the QIF scores are more highly correlated to motor power than are the FIM scores for this population. Spearman coefficients were calculated to correlate the QIF, the FIM and the UEMS. For the bathing and grooming categories, both the QIF and the FIM showed significant and similar correlations to the UEMS. For the feeding category, however, the QIF had a significantly better correlation to the UEMS than did the FIM (Rho = 0.90 vs 0.53, p < 0.01). Use of the QIF feeding scale may allow the detection of changes in function as individuals recover that the FIM scale would miss. Further evaluation of the remaining selfcare and mobility scales is needed. Modification of the FIM with more sensitive portions of the QIF would improve the discriminative ability of outcome studies and program evaluations.

Comparison of intravenous and intranasal administration of epinephrine during CPR in a canine model

STUDY OBJECTIVES

Epinephrine improves coronary perfusion pressure during CPR. However, administration of epinephrine during CPR may be delayed or omitted if IV or endotracheal access is not established. Therefore, the objective of this study was to determine if intranasal administration of epinephrine during CPR would provide an alternate route of drug administration that is readily accessible and requires no special technical skills.

DESIGN AND SETTING

Randomized blinded study performed in a controlled laboratory environment.

TYPE OF PARTICIPANTS

Twenty mongrel dogs weighing 19.5 +/- 4.6 kg.

INTERVENTIONS

All dogs received either IV epinephrine 0.015 mg/kg or intranasal epinephrine 14 mg per nostril. Phentolamine (5 mg per nostril) was administered intranasally one minute before nasal administration of epinephrine to improve absorption. Each dog underwent three minutes of ventricular fibrillation followed by seven minutes of CPR with a pneumatic chest compression device. Epinephrine was administered at two minutes into CPR.

MEASUREMENTS AND MAIN RESULTS

Seven dogs were excluded because of inadequate baseline coronary perfusion pressure or compression device displacement, leaving a total of 13 dogs for analysis (six IV epinephrine, seven intranasal epinephrine). Baseline coronary perfusion pressure (mean +/- SD) was similar for IV epinephrine and intranasal epinephrine (16.9 +/- 7.1 mm Hg versus 18.2 +/- 13.8 mm Hg, respectively, P = .84). For IV and intranasal epinephrine, coronary perfusion pressure increased to 21.4 +/- 9.2 mm Hg and 24.4 +/- 18.7 mm Hg one minute after epinephrine, respectively (P = .73). Five minutes after epinephrine coronary perfusion pressure was 18.2 +/- 8.7 mm Hg and 24.3 +/- 13.9 mm Hg for IV epinephrine and intranasal epinephrine, respectively (P = .38). The rate of successful resuscitation was similar for both groups, five of seven dogs for intranasal epinephrine and four of six dogs for IV epinephrine (P = .66).

CONCLUSION

Intranasal epinephrine has similar effects on coronary perfusion pressure and resuscitation compared with standard-dose IV epinephrine. Therefore, the nasal route for administration of epinephrine appears to be an acceptable alternate method of drug delivery during CPR and compares favorably with standard IV therapy in the canine model. Because of the obvious benefits to human patients, these observations suggest further investigation.

High-performance marketing: an interview with Nike's Phil Knight. Interview by Geraldine E. Willigan

Nike's advertising slogans--"Bo Knows," "Just Do It," and "There Is No Finish Line"--have moved beyond advertising into popular expression. Its athletic footwear and clothing have become a piece of Americana. Its brand name is as well known around the world as IBM and Coke. Behind the slogans and the flashy TV commercials is the vision of its founder, chairman, and CEO, Phil Knight. Since forming the company in 1962, Knight has taken Nike from a small-time distributor of Japanese track shoes to the top of the athletic shoe and apparel market. But not without a stumble. Along the way, Knight discovered that technological innovation alone could not continue to drive growth. When sales stagnated in the mid-1980s, Knight and Nike learned several hard lessons on how to build brands and understand consumers, and they transformed their technology company into a marketing company whose product is its most important marketing tool. "Ultimately," says Knight, "we wanted Nike to be the world's best sports and fitness company. Once you say that, you have a focus. You don't end up making wing tips or sponsoring the next Rolling Stones world tour." To keep the company growing, Nike began splitting its brands into sub-brands. In tennis, Nike divided its shoes into Challenge Court--for younger, more active players--and Supreme Court--for older, more mature players. That approach brought the company to a broader range of consumers while preserving the customer base. And to create an emotional tie with the consumer, Nike started advertising on TV. "Sports is at the heart of American culture," Knight says. "You can't explain much in 60 seconds, but when you show Michael Jordan, you don't have to. It's that simple."

Evidence that nebulin is a protein-ruler in muscle thin filaments

Partial amino acid sequence was obtained from the massive myofibrillar protein nebulin. This consists of repeating motifs of about 35 residues and super-repeats of 7 x 35 = 245 residues. The repeat-motifs are likely to be largely alpha-helical and to interact with both actin and tropomyosin in thin filaments. Nebulin from different species was found to vary in size in proportion to filament length. The data are consistent with the proposal that nebulin acts as a protein-ruler to regulate precise thin filament assembly.

Permanent junctional reciprocating tachycardia misdiagnosed as 'cardiomyopathy'

In a nine-year-old female, cardiac failure was erroneously attributed to idiopathic cardiomyopathy and cardiac transplantation was planned. The actual cause of cardiac failure was permanent junctional reciprocating tachycardia (PJRT), a rare form of supraventricular tachycardia. The diagnostic error was discovered before transplantation was performed and the arrhythmia was treated surgically. This resulted in return of near normal cardiac function.

Modification of myofibrils by fluorophore-induced photo-oxidation

The excitation of fluorophores in the vicinity of a myofibril stops both shortening in the presence of ATP and Ca2+, and the extraction of the A-band by NaCl in the presence of Mg pyrophosphate. Shortening is more quickly affected than extraction. These effects can be induced by fluorescently-tagged antibodies bound in the A-band. Both depolymerization of the thick filament and the interaction between the myosin head and actin appear to be modified. Enzymatic lowering of the oxygen concentration in the bathing solution during excitation reduces these effects, indicating that they are due to photo-oxidation catalysed by excitation of the fluorophore. The results suggest that care needs to be exercised to minimize the consequences of these changes on the outcome of fluorescence-based assays of activity. Irradiated myofibrils that do not shorten, hydrolyse ATP at a rate comparable to those that contract, so they may be useful as a model system for the study of crossbridge activity in the ordered array of proteins of the myofibril.

HIV seroprevalence among healthy blood donors in northeastern Zaire

Human immunodeficiency virus (HIV)-antibody screening of blood donors in northeastern Zaire was reviewed to determine overall seroprevalence in the population and to identify particular subgroups of the population who are at relatively high risk. Six hundred and seventy-five healthy blood donors were tested from March 1989 to May 1990 using either the HIV-CHEK or Karpas cell tests. A total of 25 donors (3.7%) were seropositive, and seropositivity was more common in female donors (5.4%) than in male donors (2.5%, P less than 0.05). Donors who came from major population centres had a higher rate of seropositivity than did individuals coming from rural villages (10.5% vs 2.0%, P less than 0.001). There was a tendency toward increasing seroprevalence during the 13 months of the study with 2.8% of donors positive in 1989 and 5.8% positive in 1990 (P less than 0.1). It is concluded that in healthy blood donors in northeastern Zaire: (1) HIV seropositivity is more frequent in women and in individuals coming from major population centres, and, (2) HIV seropositivity seems to be increasing rapidly.

Control of infection due to Klebsiella pneumoniae in an intensive care nursery

Because of an increased incidence of necrotizing enterocolitis (NEC) temporally related to Klebsiella pneumoniae colonization noted in several infants, a study was undertaken to identify the source and to eradicate the infection. Twenty infants in the neonatal intensive care unit (NICU) and 51 in the well-baby nursery were prospectively studied. Cultures were done on all infants. In addition, cultures were done on all employees and parents who regularly visited. Our results showed an increased incidence of infection during this period--8.3% as compared with 4.79% overall. Colonization with K pneumoniae was eradicated, at least temporarily, by establishing a cohort system in both the NICU and the well-baby nursery and by the administration of antibiotics to all infants in these nurseries. Colonized parents and employees were also treated. Follow-up cultures showed clearing of Klebsiella, and the cohort system was abolished. Serotyping of all affected infants later showed that different strains were present, making it unlikely that there was a common source for the Klebsiella. (Initially the source of infection had been thought to be a mother whose premature triplets were colonized. We feel that the eradication of this organism and the subsequent decline in NEC was enhanced by the combination of cohorting and handwashing. The selected use of antibiotics may have prevented an extension of the outbreak, but this could not be proven.