Analysis of an H1 receptor-mediated, zinc-potentiated vasoconstrictor action of the histidyl dipeptide carnosine in rabbit saphenous vein

The contractile action of the dipeptide carnosine (beta-alanyl-L-histidine), active as a Zn.carnosine complex (Zn. Carn), was investigated in isolated rings of rabbit saphenous vein (RSV) and was found to be antagonized by the H1 antagonist mepyramine. Mepyramine-sensitive, histamine-induced contractures in RSV, were smaller (73+/-0.1%) and less well sustained than carnosine-induced contractures. Schild plot values for mepyramine antagonism were, for carnosine-induced contractures; pA2 = 7.97+/-0.12, slope= 1.33+/-0.06 (r = 0.793) and for histamine-induced contractures; pA2 = 8.48+/-0.07, slope = 0.63+/-0.05, r = 0.957). Serotonergic antagonists methiothepin and ketanserin, antagonize both carnosine- and histamine-induced contractures in RSV, probably reflecting coincidental inhibition at the H1-receptor. Carnosine, with Zn present, can inhibit the H1-specific binding of [3H]-mepyramine to isolated guinea-pig cerebellar membranes (log IC50s - 2.78+/-0.02, -3.93+/-0.03 and -4.64+/-0.03 at 10, 30 and 80 microM Zn respectively; values corrected for the Zn-specific inhibition which has a logIC50 of -4.20). In the radioligand binding assay, the effect of carnosine can be described as a function of Zn. Carn concentration with an apparent logIC50 of -5.61. This value is consistent with that obtained from the functional studies on RSV. Histamine-induced contractures have an indomethacine-sensitive component (27.2+/-8.3% of control response), not apparent with carnosine-induced contractures. Like histamine, carnosine evoked an H2-mediated (cimetidine-sensitive) relaxation in the presence of mepyramine, but was less potent (10.8+/-3.1% residual tension at 10 mM carnosine compared with 13.4+7.5% at 0.1 mM histamine). Carnosine, like mepyramine, can 'reveal' the H2-mediated relaxation of histamine providing further evidence that carnosine binds at the H1 receptor. We conclude that carnosine can act at the smooth muscle H1-receptor to provoke vasoconstriction and that it also has the potential to act at H1-receptors in CNS.

The use of two fluorescent dyes to identify sperm in a competitive binding assay to oocytes

The relationship of most sperm laboratory assays to male fertility is inconsistent. Assays that measure traits required to fertilize oocytes are expected to have the most predictive value. A new assay that measures the competitive ability of two sperm samples to bind to oocytes was developed. Two populations of sperm were labeled using a pair of lipophilic dyes. A concentration of 75 microM of the two dyes, DiQ (4-[4-(dihexadecylamino)styryl]-N-methylquinolinium iodide; an orange-red dye) and DiOC16 (3,3'-dihexadecyloxacarbocyanine perchlorate; a yellow-green dye), intensely stained 66 and 73% of sperm, respectively, without affecting sperm motility or oocyte-binding ability. Because sperm could be stained with fluorescent dyes, sperm from two semen samples were mixed together in a droplet, and oocytes were added to allow sperm to bind oocytes competitively. Oocyte-bound sperm from each sample were counted. Binding was specific; nonspecific sperm binding was estimated by sperm bound to two-cell mouse embryos and averaged one to three sperm per embryo. Staining with DiQ or DiOC16 did not affect oocyte-binding ability since more than 80% of the sperm bound were stained with either dye. Furthermore, if different ratios of DiQ- or DiOC16-stained sperm from the same ejaculate were prepared in droplets and oocytes were added, the percentage of sperm bound to the oocytes reflected the percentage of sperm in the droplet; there was no differential effect of either dye. This assay used fixed oocytes because sperm bound equally to fixed and fresh bovine oocytes. This competitive oocyte-binding assay allows one to make a series of pairwise comparisons between a group of males or to include an internal control sample in sperm-oocyte binding assays. This assay may allow more accurate prediction of the oocyte-binding ability of sperm.

Effects of cyclic adenosine monophosphate (cAMP) on sarcoplasmic reticulum Ca(2+)-loading in failing rabbit and human cardiac trabeculae

The response of cardiac SR Ca(2+)-loading to cAMP in failing rabbit and human myocardium was examined. Right ventricular (RV) trabeculae were isolated and mounted for isometric tension measurement. They were treated with saponin to permeabilise the sarcolemma but retain SR function, and bathed in a mock intracellular solution including adenosine triphosphate (ATP) and buffered calcium. Caffeine (10 mM) was used to release calcium from the SR. The amplitude of the caffeine-induced contracture was used as a quantitative gauge of the calcium content of the SR. Trabeculae were isolated from rabbits with coronary ligation-induced heart failure (LIG, n = 11), sham operated controls (SH, n = 10), isoprenaline-infused rabbits (ISO, 7 days mini-osmotic pump 100 micrograms/kg.h; n = 7) and saline-infused controls (SAL, n = 7). Failing human RV trabeculae were obtained at the time of cardiac transplantation. Failing rabbit trabeculae demonstrated increased baseline caffeine-induced contractures compared with controls, the response to cAMP was similar in the two groups (LIG 9.3 +/- 2.8 vs SH 10.6 +/- 3.2% Fmax; P = 0.55), There was no difference in the baseline SR Ca(2+)-loading in ISO trabeculae compared with SAL controls but there was a marked difference in the response to cAMP (11.1 +/- 5.4 vs 4.2 +/- 2.1% Fmax, P = 0.02). SR Ca(2+)-loading in failing human RV trabeculae was related to the severity of LV dysfunction (r = 0.59, P = 0.04) and demonstrated a marked cAMP-induced enhancement of caffeine-contracture (20.2 +/- 4.7% increase of Fmax) which was greater in patients with low compared with high ejection fraction. While beta-receptors are known to be down regulated in heart failure these results suggest that the scope for cAMP-mediated enhancement of SR Ca(2+)-loading is maintained.

Targeting of IgMkappa antibodies to oligodendrocytes promotes CNS remyelination

We previously identified the remyelinating activity of a natural IgMkappa oligodendrocyte-reactive autoantibody (SCH94.03), using a virus-induced murine model of multiple sclerosis. We now describe a second mouse IgMkappa monoclonal antibody (mAb) (SCH79.08) raised against normal mouse spinal cord homogenate, which reacts with myelin basic protein and also promotes remyelination. Because these two mAbs recognize different oligodendrocyte antigens, several previously identified oligodendrocyte-reactive IgMkappa mAbs (O1, O4, A2B5, and HNK-1), each with distinct antigen specificities, were evaluated and found to promote remyelination. In contrast, IgMkappa mAbs that did not bind to oligodendrocytes showed no remyelination. One of these, CH12 IgMkappa mAb, which shares variable region cDNA sequences with SCH94.03 except for amino acid differences in the complementarity-determining region 3 in both heavy and light chains, did not bind to oligodendrocytes and did not promote remyelination. The fact that multiple oligodendrocyte-reactive antibodies with distinct antigen reactivities induce remyelination argues against direct activation by a unique cell surface receptor. These findings are most consistent with the hypothesis that the binding of mAbs to oligodendrocytes in the lesions induces myelin repair via indirect immune effector mechanisms initiated by the mu-chain. Importantly, these studies indicate that oligodendrocyte-reactive natural autoantibodies may provide a powerful and novel therapeutic means to induce remyelination in multiple sclerosis patients.

Psychological characteristics of candidates for liver transplantation

This study examined depression, anxiety, coping styles, optimism, selected personality characteristics, and perception of family environment among candidates for liver transplantation (OLTX); the goal was to measure and empirically describe psychosocial factors reported to impact on the experience and outcome of transplantation. Subjects were 73 US military veterans being considered for OLTX at the VAMC-Pittsburgh (UD) from 1994 to 1996. Psychological evaluation consisted of chart review, consultation with the transplant team, clinical interview and administration of published, standardized, and readily available psychological tests. Candidates displayed above normal levels of situational anxiety and depression, mainly adaptive coping styles, mild optimism, and positive family environments. Factor analysis of the data identified two dimensions of psychological distress, five coping styles, and three types of family environment. The composite MMPI-2 profile for the sample shows marked elevations of the neurotic triad and moderate elevations of psychasthenia and schizophrenia scales. Psychological distress, psychopathology, coping styles, optimism, and perceptions of family environment correlate with each other in the directions suggested by the literature. These findings support previous research with empirical data; results encourage the development of consistent psychological protocols and procedures to evaluate and treat organ transplant candidates.

Sarcoplasmic reticulum Ca2+ loading in rabbits 8 and 15 weeks after coronary artery ligation

Calcium uptake by cardiac sarcoplasmic reticulum (SR) is reported to be reduced in heart failure in the human and in a number of animal models. However, the majority of studies have examined end-stage heart failure in the human and few animal studies have taken account of the duration and severity of left ventricular dysfunction. In this study we have compared SR Ca2+ loading in a haemodynamically assessed, coronary artery ligation model of heart failure at 8 and 15 weeks after ligation. Trabeculae were isolated from the right ventricle and mounted for isometric tension measurement. They were treated with saponin to permeabilize the sarcolemma but retain SR function and bathed in a mock intracellular solution including adenosine triphosphate (ATP) and buffered Ca2+. Caffeine was used to release Ca2+ from the SR. The amplitude of the caffeine-induced contracture was used as a quantitative gauge of the Ca2+ content of the SR. Eight weeks after ligation, trabeculae demonstrated enhanced SR Ca2+ uptake as manifest by larger caffeine-induced contractures (e.g. 200 nM [Ca2+], 120 s loading - 38.2+/-9.2 versus 67.3+/-10.1% of maximum Ca2+-activated force, FCa, max, P=0.03). At 15 weeks, trabeculae from ligated hearts were not significantly different from controls with SR Ca2+ loading returning to control levels (e.g. 200 nM [Ca2+], 120 s loading - 47.3+/-9.6 versus 30.2+/-12.8% FCa, max, P=0.12). These data suggest that SR Ca2+ loading may increase in the early stages of heart failure and fall back to normal with an increasing duration of left ventricular dysfunction. Increased incidence of spontaneous Ca2+ release observed from the SR at 8 weeks and not at 15 weeks may represent an arrhythmogenic mechanism specific to the early phase of heart failure.

Pax-6 origins--implications from the structure of two coral pax genes

Vertebrate Pax-6 and its Drosophila homolog eyeless play central roles in eye specification, although it is not clear if this represents the ancestral role of this gene class. As the most "primitive" animals with true nervous systems, the Cnidaria may be informative in terms of the evolution of the Pax gene family. For this reason we surveyed the Pax gene complement of a representative of the basal cnidarian class (the Anthozoa), the coral Acropora millepora. cDNAs encoding two coral Pax proteins were isolated. Pax-Aam encoded a protein containing only a paired domain, whereas Pax-Cam also contained a homeodomain clearly related to those in the Pax-6 family. The paired domains in both proteins most resembled the vertebrate Pax-2/5/8 class, but shared several distinctive substitutions. As in most Pax-6 homologs and orthologs, an intron was present in the Pax-Cam locus at a position corresponding to residues 46/47 in the homeodomain. We propose a model for evolution of the Pax family, in which the ancestor of all of the vertebrate Pax genes most resembled Pax-6, and arose via fusion of a Pax-Aam-like gene (encoding only a paired domain) with an anteriorly-expressed homeobox gene resembling the paired-like class.

Linkage of genes encoding enolase (eno) and CTP synthase (pyrG) in the beta-subdivision proteobacterium Nitrosomonas europaea

The gene encoding enolase (eno) from the ammonia oxidising bacterium Nitrosomonas europaea has been cloned and sequenced. The deduced amino acid sequence for enolase from N. europaea was 65% identical (76% similar) to its Bacillus subtilis orthologue. An incomplete open reading frame located 432 bp 5' of eno was identified as pyrG, which encodes CTP synthase. These two genes are therefore organised in N. europaea, a beta-subdivision proteobacterium, in the same way as in the gamma-subdivision proteobacterium Escherichia coli.

Powdery Mildew Caused by an Oidium sp. in Alfalfa in Wisconsin

In July 1996 and August 1997, dense amphigenous mycelia bearing Oidium conidia infected the lower stems and leaves of alfalfa (Medicago sativa L.) plants in research nurseries in south-central Wisconsin, causing the defoliation of the affected leaves. In the greenhouse, the disease spread rapidly from transplanted field plants to adjacent flats of alfalfa seedlings. A teleomorphic state of the fungus was not observed. Morphological characteristics of the oidia were similar to those of Erysiphe pisi (1). Conidia were ellipsoid-cylindrical and closely resembled those shown from Pisum sativum L. (2). Dry (2) conidia averaged 14.6 × 41.4 μm (range: 13.0 to 15.6 × 39 to 46.8 μm). Conidia shaken from mildewed alfalfa plants onto plants of garden pea (Pisum sativum) cv. Early Perfection and red clover (Trifolium pratense L.) cv. Lakeland infected both hosts. However, powdery mildew developed sooner and was much more severe in pea than in red clover. Noninoculated control plants remained free of powdery mildew. This is the first report of powdery mildew in alfalfa in Wisconsin fields. In extensive pathogenicity studies in greenhouses in Wisconsin (2), conidia from at least one isolate from red clover infected Medicago falcata L. and M. sativa L. var. glutinosa Urban, but not alfalfa cv. Vernal. References: (1) H. J. Boesewinkel. Bot. Rev. 46:167, 1980. (2) J. R. Stavely and E. W. Hanson. Phytopathology 56:309, 1966.

Light-regulated transcription of genes encoding peridinin chlorophyll a proteins and the major intrinsic light-harvesting complex proteins in the dinoflagellate amphidinium carterae hulburt (Dinophycae). Changes In cytosine methylation accompany photoadaptation

In the dinoflagellate Amphidinium carterae, photoadaptation involves changes in the transcription of genes encoding both of the major classes of light-harvesting proteins, the peridinin chlorophyll a proteins (PCPs) and the major a/c-containing intrinsic light-harvesting proteins (LHCs). PCP and LHC transcript levels were increased up to 86- and 6-fold higher, respectively, under low-light conditions relative to cells grown at high illumination. These increases in transcript abundance were accompanied by decreases in the extent of methylation of CpG and CpNpG motifs within or near PCP- and LHC-coding regions. Cytosine methylation levels in A. carterae are therefore nonstatic and may vary with environmental conditions in a manner suggestive of involvement in the regulation of gene expression. However, chemically induced undermethylation was insufficient in activating transcription, because treatment with two methylation inhibitors had no effect on PCP mRNA or protein levels. Regulation of gene activity through changes in DNA methylation has traditionally been assumed to be restricted to higher eukaryotes (deuterostomes and green plants); however, the atypically large genomes of dinoflagellates may have generated the requirement for systems of this type in a relatively "primitive" organism. Dinoflagellates may therefore provide a unique perspective on the evolution of eukaryotic DNA-methylation systems.

Attitudes of the physician membership of the society for adolescent medicine toward medical abortions for adolescents

OBJECTIVE

To document the practices and attitudes of the US physician members of the Society for Adolescent Medicine (SAM) regarding adolescent abortion and contraception, as well as physician willingness to prescribe medical abortion if approved by the Food and Drug Administration (FDA).

DESIGN

Cross-sectional questionnaire survey. Participants. The entire physician membership of SAM (N = 1001) was surveyed. A total of 713 physicians responded, with 668 usable surveys yielding an adjusted response rate of 70%.

RESULTS

Of the respondents, 81% were trained as pediatricians; 58% had additional adolescent medicine training. Ninety-six percent prescribed contraception for their patients. Sixty-one percent of respondents identified abortion as an option for pregnant adolescents in all circumstances, whereas 4% believed abortion should never be an option. Eighty-nine percent referred their patients for abortions; 90% were aware of medications to induce abortions medically. If these medications (methotrexate and misoprostol, RU-486) were FDA-approved, 42% would prescribe them for their patients; 34% were unsure. Fifty-four percent believed if medical abortions were routinely available, they should be available from primary care physicians. Physicians were significantly more likely to consider prescribing medical abortions if the physician were female, offered postcoital contraception, performed Norplant insertions, referred adolescents for abortions, or performed postabortion medical checkups. Physicians were no more likely to consider prescribing medical abortions according to physician age, specialty training, or date of residency training. Religious affiliation per se was not associated with likelihood of prescribing medical abortions, but Catholic physicians were significantly less likely to consider prescribing medical abortions.

CONCLUSIONS

Virtually all SAM physician respondents (96%) reported that abortion for pregnant adolescents should be available under some circumstances. Forty-two percent would prescribe medical abortion if the medications were FDA-approved, suggesting that medical abortion would potentially be available to adolescents from a larger group of physicians than is currently available.

Method for determining the solubilities of hydrophobic organics in subcritical water

A rapid and simple method has been developed to determine the solubility of organic compounds in water at temperatures from 25 to 250 degrees C and with enough pressure to maintain the liquid state ("subcritical" water). Water is heated and then passed through a cell containing excess test solute. The water, now saturated with solute, is blended with chloroform, cooled, and collected, and the chloroform fraction is analyzed by gas chromatography. Replicate determinations have typical reproducibilities, indicated by the relative standard deviation, of < 5%. Solubilities at 25 degrees C determined by this method are in good agreement with published data. Increasing the temperature of water from 25 degrees C to near the normal melting point of the organic solute results in solubility enhancements ranging from 6-fold for naphthalene (at 65 vs 25 degrees C) to 130,000-fold for chlorothalonil (at 200 vs 25 degrees C).

The accuracy of substituted judgments in patients with terminal diagnoses

BACKGROUND

Patients' loved ones often make end-of-life treatment decisions, but the accuracy of their substituted judgments and the factors associated with accuracy are poorly understood.

OBJECTIVE

To assess the accuracy of judgments made by surrogate decision makers; ascertain the beliefs, practices, and clinical and sociodemographic factors associated with accuracy of surrogates' decisions; assess the preferences of patients for life-sustaining treatments; and compare differences in accuracy across diagnoses.

DESIGN

Cross-sectional paired interviews.

SETTING

Outpatient practices of three university hospitals.

PATIENTS

250 patients with terminal diagnoses of congestive heart failure, AIDS, amyotrophic lateral sclerosis, lung cancer, and chronic obstructive pulmonary disease (50 patient-surrogate pairs in each group) and 50 general medical patients and their surrogates.

MEASUREMENTS

The accuracy of surrogate predictions was measured by using scales based on 10 potential treatments in each of three hypothetical clinical scenarios.

RESULTS

Preferences varied according to mode of treatment and scenario. On average, surrogates made correct predictions in 66% of instances. Accuracy was better for the permanent coma scenario than for the scenarios of severe dementia or coma with a small chance of recovery (P < 0.001). In a binary logit model, the accuracy of substituted judgments was positively associated with the patient having spoken with the surrogate about end-of-life issues (odds ratio [OR], 1.9 [95% CI, 1.6 to 2.3]), the patient having private insurance (OR, 1.4 [CI, 1.1 to 1.7]), the surrogate's level of education (OR, 1.5 [CI, 1.2 to 1.9]), and the patient's level of education (OR, 1.7 [CI, 1.4 to 2.2]). Accuracy was negatively associated with the patient's belief that he or she would live longer than 10 years (OR, 0.6 [CI, 0.5 to 0.7]), surrogate experience with life-sustaining treatment (OR, 0.4 [CI, 0.3 to 0.5]), surrogate participation in religious services (OR, 0.67 [CI, 0.50 to 0.91]), and a diagnosis of heart failure (OR, 0.6 [CI, 0.5 to 0.8]). Age, ethnicity, marital status, religion, and advance directives were not associated with accuracy.

CONCLUSIONS

The accuracy of substituted judgments is associated with multiple clinically apparent patient and surrogate factors. This information can help clinicians identify conditions under which substituted judgments are likely to be accurate or inaccurate and can help target populations for education designed to improve the accuracy of surrogate decision making.

Effects of in vitro and in vivo exposure to doxorubicin (adriamycin) on caffeine-induced Ca2+ release from sarcoplasmic reticulum and contractile protein function in 'chemically-skinned' rabbit ventricular trabeculae

Doxorubicin is an anthracycline antibiotic that is used widely as a chemotherapeutic agent. However, the usefulness of this agent is limited due to its cardiotoxic effects. The mechanisms associated with this cardiotoxicity remain essentially unknown, despite numerous studies describing a range of structural and functional abnormalities. The purpose of the present study was to determine the in vivo and in vitro effects of doxorubicin exposure on sarcoplasmic reticulum (SR) Ca2+-content and contractile protein function. The Ca2+-content of SR is shown to have a biphasic response to in vivo and in vitro doxorubicin exposure that is time- and dose-dependent. In vitro doxorubicin exposure initially reduces the SR Ca2+-content, but the predominant action to block the SR Ca2+-release channel increases SR Ca2+-content within 60 min. Similar results are observed with in vivo doxorubicin exposure: it leads to Ca2+-overload. These data are consistent with the view that doxorubicin acts in a similar manner to ryanodine and results in cardiomyopathy due to Ca2+-overload.

Solid-phase microextraction of polychlorinated biphenyls

The extraction and analysis of 21 polychlorinated biphenyls (PCBs) ranging from di- to decachlorobiphenyls in ocean, wetland and leachate water samples were achieved using solid-phase microextraction (SPME) with a 100-micron poly(di-methylsiloxane) (PDMS) fiber and gas chromatography-electron-capture detection (GC-ECD). Severe carryover between samples (e.g., 20%) occurs on both stir bars and the SPME fibers demonstrating that it is important to use a new stir bar for each sample, as well as to perform SPME-GC blanks between samples to avoid quantitative errors. The equilibrium partitioning coefficients of individual PCB congeners between PDMS and water were found to be surprisingly different compared to their octanol-water partitioning coefficient (Kow), demonstrating that Kow cannot be used to estimate the partitioning behavior of PCBs in the SPME process. Using a 15-min SPME extraction, SPME analysis with GC-ECD was linear (r2 > or = 0.97) from approximately 5 pg/ml to the solubility limit of each congener. Concentrations in water samples obtained by 15-min SPME extractions compared favorably with those obtained by toluene extractions, demonstrating that SPME combined with GC is a useful technique for the rapid determination of PCBs in water samples.

Identification of a novel family of non-lysosomal aspartic proteases in nematodes

A protein encoded by cDNAs from the human parasite Onchocerca volvulus and its homologs from Caenorhabditis elegans and Ancyclostoma caninum define a family of aspartic proteases that are most closely related to cathepsins D, but differ from them in lacking the N-glycosylation site known to be required for lysosomal targeting. The nematode proteins have a potential N-glycosylation site at the same position as mammalian cathepsins E and in common with these have atypically long N-terminal extensions. The literature implies that cathepsins E may be secreted, and adult female O. volvulus are known to secrete a specific inhibitor of aspartic proteases; we therefore predict that the protease is secreted as an enzyme-inhibitor complex.

New Orientia tsutsugamushi strain from scrub typhus in Australia

In a recent case of scrub typhus in Australia, Orientia tsutsugamushi isolated from the patient's blood was tested by sequence analysis of the 16S rDNA gene. The sequence showed a strain of O. tsutsugamushi that was quite different from the classic Karp, Kato, and Gilliam strains. The new strain has been designated Litchfield.

Physical therapists' opinions and practices regarding direct access

BACKGROUND AND PURPOSE

This study examined whether differences exist about physical therapists' opinions and practices regarding the use of direct access between therapists practicing in Massachusetts, a direct-access state, and therapists practicing in Connecticut, a state that allows only evaluation without referral. A second purpose was to examine direct-access practices of therapists in Massachusetts.

SUBJECTS

A sample of 329 therapists in Massachusetts and 179 therapists in Connecticut were surveyed.

METHODS

A cover letter, questionnaire, and return-reply envelope were mailed to each therapist. Independent group t tests and chi-square analyses were used to determine whether therapists' opinions about direct access differed between states. Frequencies were calculated to examine direct-access practices of therapists in Massachusetts.

RESULTS

Adjusted response rates were 65.5% in Massachusetts and 57.9% in Connecticut. Therapists in both states were equally supportive of direct access (74.9%). Therapists in Connecticut were more supportive of three stipulations regulating direct access than therapists in Massachusetts were. In Massachusetts, 34.0% of the respondents stated that they practiced using direct access, and 8.8% of the patients seen by the therapists sampled were treated without physicians' referrals. The therapists indicated that the most common reasons for limited use of direct access were employer policies and lack of insurance reimbursement.

CONCLUSION AND DISCUSSION

Therapists in Connecticut favored more stipulation regulating direct access than therapists in Massachusetts did. Although therapists in both states appear to be supportive of direct access, the number of patients in Massachusetts seen through this mode of care appears to be limited because of practice and financial restraints.

Monoclonal remyelination-promoting natural autoantibody SCH 94.03: pharmacokinetics and in vivo targets within demyelinated spinal cord in a mouse model of multiple sclerosis

Chronic inflammatory demyelination of the central nervous system is usually incompletely repaired. However, we previously reported that in vivo treatment with monoclonal antibody SCH 94.03 (produced using spinal cord homogenate as an immunogen) increased myelin repair 4-fold in the Theiler's virus mouse model of chronic progressive multiple sclerosis (Miller et al., 1994; J. Neurosci. 14: 6230-6238). A major issue regarding site and mechanism of action of this antibody is whether SCH 94.03 enters demyelinated CNS lesions and reacts with oligodendrocytes and myelin. To address this question, we radiolabeled SCH 94.03 and studied its distribution into tissues, pharmacokinetics, and binding to cells within demyelinating spinal cord lesions in vivo. SCH 94.03 distributed widely into extracellular water following intraperitoneal injection and was eliminated with a terminal half-life of 3-4.5 days. Only a portion of the total dose (0.4%) entered brain and spinal cord. SCH 94.03 accumulated 1.5-2.0-fold in brain between 1 and 7 days after injection, but its pharmacokinetics were otherwise similar to those of an isotype control IgMkappa antibody. Oligodendrocytes, myelin sheaths and, less frequently, axons were labeled within demyelinating lesions as detected by light and electron microscopic autoradiography. These findings suggest that remyelination-promoting autoantibodies could act within the demyelinating lesion of the central nervous system by binding to the oligodendrocyte, myelin, or axon.

Preliminary characterisation of an Onchocerca volvulus aspartic protease

PCR using 1 primer specific for aspartic proteases and 1 primer annealing to the vector allowed amplification of a 377 bp fragment encoding part of an aspartic protease from an Onchocerca volvulus cDNA library. Use of this fragment as a probe allowed the isolation of a larger cDNA clone. In common with 2 other nematode aspartic proteases, the O. volvulus predicted protein has several of the general characteristics of this class of proteins, but lacks specific determinants of lysosomal localisation.

Measuring psychological distress in candidates for liver transplantation: a pilot study

A protocol to evaluate the psychopathology of candidates for orthotopic (whole organ) liver transplantation (OLTX) is presented. Patients being considered for OLTX at the VA Pittsburgh Healthcare System were routinely referred for psychological evaluation consisting of a clinical interview and battery of standardized tests. The findings on 26 patients corroborate previous reports of psychological distress among transplant candidates. There is also evidence that higher levels of disturbance are observed among patients with a positive history of substance abuse. This study supports the value of standardized testing in the transplant population and suggests directions for further research.

Sperm from a variety of mammalian species express beta1,4-galactosyltransferase on their surface

In mice, initial gamete recognition is mediated by the binding of sperm surface beta1,4-galactosyltransferase (GalTase) to a glycoprotein of the zona pellucida, ZP3. When sperm bind to the zona pellucida, ZP3 induces the acrosome reaction by aggregating GalTase. The acrosome reaction releases acrosomal enzymes allowing sperm to pass through the zona pellucida, bind to the egg membrane, and activate development. In addition to GalTase, there is evidence that other sperm proteins may also bind ZP3. Although fertilization in the mouse is morphologically similar to fertilization in most other mammalian species, the degree of parallelism at the molecular level is not well defined. Less information is available about the molecular details of fertilization in other species. The aim of this work was to determine whether sperm from other mammalian species express GalTase on their surface. We performed GalTase enzyme assays on sperm from six species, and all six expressed GalTase on their surface. The amounts of GalTase varied between species. Guinea pig, mouse, and rat sperm had higher levels of GalTase than bovine, porcine, and rabbit sperm. GalTase was localized by immunofluorescence on live and fixed sperm to the anterior portion of the sperm head in all species examined. This is the expected location for a receptor that binds the zona pellucida. Biotinylation of sperm surface proteins confirmed that GalTase detected by immunofluorescence and enzyme assay was expressed on the sperm surface. These results demonstrate that various mammalian species express GalTase on their surface and that it is found in the proper location to bind to the zona pellucida.

Two graduating master's students struggle to find meaning

This article was initiated to help two graduating Master's students learn what might be expected of them upon graduation. The purpose of this article is to provide insight from reviewing the current literature on clinical nurse specialist's (CNS's) characteristics. The authors believe that this information is especially useful for graduate CNS students and helpful for those who currently hold CNS positions. Based on a literature review, the article categorizes descriptions of the characteristics of the CNS role as perceived by the CNS, management, staff nurses, and physicians. Within the identified perceptions of each group were the following similarly common CNS role components: (a) clinical practice, (b) education, (c) administration, (d) research, and (e) consultation. The key to congruent expectations and understanding of the CNS role is clear communication between the members of each group. Without this communication, the common result is ambiguity, conflict, and frustration.