Using Computed Tomography-Based Three-dimensional Modeling and Computer Navigation for Minimally Invasive Core Decompression and Adjuvant Orthobiologic Therapy of Femoral Head Avascular Necrosis

Avascular necrosis of the femoral head is a debilitating condition that can lead to femoral head collapse. Core decompression with adjuvant cellular therapies, such as bone marrow aspirate concentrate, delays disease progression and improves outcomes. However, inconsistent results in the literature may be due to limitations in surgical technique and difficulty in targeting the necrotic lesions. Here, we present a surgical technique utilizing computed tomography-based three-dimensional modeling and instrument tracking to guide the therapy to the center of the lesion. This method minimizes the number of attempts to reach the lesion and confirms the three-dimensional positioning of the instrumentation within the lesion. Our technique may improve the outcomes of core decompression and adjuvant therapy and prevent or delay hip collapse in patients with femoral head avascular necrosis.

Owner reported diseases of working equids in central Ethiopia

REASONS FOR PERFORMING STUDY

Working horses, donkeys and mules suffer from numerous diseases and clinical problems. However, there is little information on what owners perceive as important health concerns in their working animals.

OBJECTIVES

To identify and prioritise with owners the diseases and other health concerns in working equids in central Ethiopia using participatory methodologies.

STUDY DESIGN

Participatory situation analysis (PSA).

METHODS

The study was conducted with carthorse- and donkey-owners in 16 sites in central Ethiopia. Multiple participatory methodologies were utilised, including ranking, matrices and focus group discussions. Owners' perceptions on frequency, importance, morbidity and mortality of volunteered diseases and the clinical signs that owners attributed to each disease were obtained; information regarding the impact of these diseases and health concerns was also sought.

RESULTS

A total of 40 separate disease and health problems were volunteered by carthorse- and donkey-owners. Horse-owners volunteered a musculoskeletal syndrome (with the local name 'bird', clinical signs suggest possible disease pathologies including equine exertional rhabdomyolysis), colic and epizootic lymphangitis most frequently, whereas donkey-owners volunteered sarcoids, nasal discharge and wounds to occur most frequently. One problem (coughing) was volunteered frequently by both horse- and donkey-owners. Owners demonstrated knowledge of differing manifestations and severity of these problems, which resulted in differing impacts on the working ability of the animal.

CONCLUSIONS

Although many of the diseases and clinical signs had been previously reported, this study also identified some previously unreported priorities such as rabies in donkeys, an unidentified musculoskeletal syndrome in horses and respiratory signs in both horses and donkeys. The information gathered during this participatory study with owners may be used to inform future veterinary and educational programme interventions, as well as identify future research priorities.

A cluster-randomised controlled trial to compare the effectiveness of different knowledge-transfer interventions for rural working equid users in Ethiopia

There have been few studies evaluating the efficacy of knowledge-transfer methods for livestock owners in developing countries, and to the authors' knowledge no published work is available that evaluates the effect of knowledge-transfer interventions on the education of working equid users. A cluster-randomised controlled trial (c-RCT) was used to evaluate and compare the effectiveness of three knowledge-transfer interventions on knowledge-change about equid health amongst rural Ethiopian working equid users. Groups were exposed to either; an audio programme, a village meeting or a diagrammatic handout, all of which addressed identical learning objectives, and were compared to a control group which received no intervention. Thirty-two villages were randomly selected and interventions randomly assigned. All participants in a village received the same intervention. Knowledge levels were assessed by questionnaire administration. Data analysis included comparison of baseline data between intervention groups followed by multilevel linear regression models (allowing for clustering of individuals within village) to evaluate the change in knowledge between the different knowledge-transfer interventions. A total of 516 randomly selected participants completed the pre-intervention questionnaire, 504 of whom undertook the post-dissemination questionnaire, a follow up response rate of 98%. All interventions significantly improved the overall 'change in knowledge' score on the questionnaire compared to the control, with the diagrammatic handout (coefficient (coef) 9.5, S.E.=0.6) and the village meeting (coef 9.7, S.E.=0.6) having a significantly greater impact than the audio programme (coef 4.8, S.E.=0.6). Covariates that were different at baseline, and which were also significant in the final model, were age and pre-intervention score. Although they had a minimal effect on the intervention coefficients there was a significant interaction between age and intervention. This study should aid the design of education materials for adult learning for working equid users and other groups in developing countries.

Clinical and subclinical mastitis in smallholder dairy farms in Tanzania: Risk, intervention and knowledge transfer

In a cross-sectional study of 400 randomly selected smallholder dairy farms in the Tanga and Iringa regions of Tanzania, 14.2% (95% confidence interval (CI)=11.6-17.3) of cows had developed clinical mastitis during the previous year. The point prevalence of subclinical mastitis, defined as a quarter positive by the California Mastitis Test (CMT) or by bacteriological culture, was 46.2% (95% CI=43.6-48.8) and 24.3% (95% CI=22.2-26.6), respectively. In a longitudinal disease study in Iringa, the incidence of clinical mastitis was 31.7 cases per 100 cow-years. A randomised intervention trial indicated that intramammary antibiotics significantly reduced the proportion of bacteriologically positive quarters in the short-term (14 days post-infusion) but teat dipping had no detectable effect on bacteriological infection and CMT positive quarters. Other risk and protective factors were identified from both the cross-sectional and longitudinal included animals with Boran breeding (odds ratio (OR)=3.40, 95% CI=1.00-11.57, P<0.05 for clinical mastitis, and OR=3.51, 95% CI=1.29-9.55, P<0.01 for a CMT positive quarter), while the practice of residual calf suckling was protective for a bacteriologically positive quarter (OR=0.63, 95% CI=0.48-0.81, P<or=0.001) and for a CMT positive quarter (OR=0.69, 95% CI=0.63-0.75, P<0.001). A mastitis training course for farmers and extension officers was held, and the knowledge gained and use of different methods of dissemination were assessed over time. In a subsequent randomised controlled trial, there were strong associations between knowledge gained and both the individual question asked and the combination of dissemination methods (village meeting, video and handout) used. This study demonstrated that both clinical and subclinical mastitis is common in smallholder dairying in Tanzania, and that some of the risk and protective factors for mastitis can be addressed by practical management of dairy cows following effective knowledge transfer.

The effects of different knowledge-dissemination interventions on the mastitis knowledge of Tanzanian smallholder dairy farmers

We developed three different knowledge-dissemination methods for educating Tanzanian smallholder farmers about mastitis in their dairy cattle. The effectiveness of these methods (and their combinations) was evaluated and quantified using a randomised controlled trial and multilevel statistical modelling. To our knowledge, this is the first study that has used such techniques to evaluate the effectiveness of different knowledge-dissemination interventions for adult learning in developing countries. Five different combinations of knowledge-dissemination method were compared: 'diagrammatic handout' ('HO'), 'village meeting' ('VM'), 'village meeting and video' ('VM+V'), 'village meeting and diagrammatic handout' ('VM+HO') and 'village meeting, video and diagrammatic handout' ('VM+V+HO'). Smallholder dairy farmers were exposed to only one of these interventions, and the effectiveness of each was compared to a control ('C') group, who received no intervention. The mastitis knowledge of each farmer (n=256) was evaluated by questionnaire both pre- and post-dissemination. Generalised linear mixed models were used to evaluate the effectiveness of the different interventions. The outcome variable considered was the probability of volunteering correct responses to mastitis questions post-dissemination, with 'village' and 'farmer' considered as random effects in the model. Results showed that all five interventions, 'HO' (odds ratio (OR)=3.50, 95% confidence intervals (CI)=3.10, 3.96), 'VM+V+HO' (OR=3.34, 95% CI=2.94, 3.78), 'VM+HO' (OR=3.28, 95% CI=2.90, 3.71), 'VM+V' (OR=3.22, 95% CI=2.84, 3.64) and 'VM' (OR=2.61, 95% CI=2.31, 2.95), were significantly (p<0.0001) more effective at disseminating mastitis knowledge than no intervention. In addition, the 'VM' method was less effective at disseminating mastitis knowledge than other interventions. Combinations of methods showed no advantage over the diagrammatic handout alone. Other explanatory variables with significant positive associations on mastitis knowledge included education to secondary school level or higher, and having previously learned about mastitis by reading pamphlets or attendance at an animal-health course.

Side-effects of antituberculosis drug treatment in patients with chronic renal failure

Patients with chronic renal failure (CRF) have a high incidence of tuberculosis (TB). Those from the Indian subcontinent are at particular risk. The frequency of side-effects associated with antituberculous treatment in a group of patients with CRF was studied. All cases of TB in patients with CRF occurring over a 13-yr period at the Manchester Royal Infirmary, from 1986-1999, were identified by diagnostic coding, microbiology records and a TB database. The case notes were then reviewed. Twenty-four cases were identified, eight predialysis and 16 requiring regular dialysis. TB occurring in the dialysis group was extrapulmonary in every case. Nineteen of 24 (79%) patients were of Indian subcontinent origin and 14 of 16 (87%) dialysis patients were non-Caucasian. Adverse effects of treatment occurred in two of eight (25%) in the predialysis group and nine of 16 (56%) of the dialysis group. These were most commonly neuropsychiatric (6), hepatic (4) and gastrointestinal (4). Neuropsychiatric symptoms occurred exclusively in dialysis patients. In conclusion, a high incidence of side-effects from antituberculous medication, especially neuropsychiatric, hepatic and gastrointestinal, was identified in patients with chronic renal failure. Careful monitoring for side-effects is essential in this group, and consideration should be given to administering antituberculous chemoprophylaxis to all high-risk groups.

Crystal structure of the lambda repressor C-terminal domain octamer

The three-dimensional structure of the lambda repressor C-terminal domain (CTD) has been determined at atomic resolution. In the crystal, the CTD forms a 2-fold symmetric tetramer that mediates cooperative binding of two repressor dimers to pairs of operator sites. Based upon this structure, a model was proposed for the structure of an octameric repressor that forms both in the presence and absence of DNA. Here, we have determined the structure of the lambda repressor CTD in three new crystal forms, under a wide variety of conditions. All crystals have essentially the same tetramer, confirming the results of the earlier study. One crystal form has two tetramers bound to form an octamer, which has the same overall architecture as the previously proposed model. An unexpected feature of the octamer in the crystal structure is a unique interaction at the tetramer-tetramer interface, formed by residues Gln209, Tyr210 and Pro211, which contact symmetry-equivalent residues from other subunits of the octamer. Interestingly, these residues are also located at the dimer-dimer interface, where the specific interactions are different. The structures thus indicate specific amino acid residues that, at least in principle, when altered could result in repressors that form tetramers but not octamers.

Structure of a variant of lac repressor with increased thermostability and decreased affinity for operator

A single amino acid substitution, K84L, in the Escherichia coli lac repressor produces a protein that has substantially increased stability compared to wild-type. However, despite the increased stability, this altered tetrameric repressor has a tenfold reduced affinity for operator and greatly decreased rate-constants of inducer binding as well as a reduced phenotypic response to inducer in vivo. To understand the dramatic increase in stability and altered functional properties, we have determined the X-ray crystal structures of a dimeric repressor with and without the K84L substitution at resolutions of 1.7 and 3.0 A, respectively. In the wild-type dimer, K84-11, Lys84 forms electrostatic interactions at the monomer-monomer interface and is partially exposed to solvent. In the K84L-11 substituted protein there is reorientation of the N-subdomains, which allows the leucine to become deeply buried at the monomer-monomer interface. This reorientation of the N-subdomains, in turn, results in an alteration of hydrogen bonding, ion pairing, and van der Waals interactions at the monomer-monomer interface. The lysine residue at position 84 appears to exert its key effects by destabilizing the "optimal" conformation of the repressor, effectively loosening the dimer interface and allowing the repressor to adopt the conformations necessary to function as a molecular switch.

Crystallographic analysis of Lac repressor bound to natural operator O1

Previous structures of Lac repressor bound to DNA used a fully symmetric "ideal" operator sequence that is missing the central G-C base-pair present in the three natural operator sequences. Here we have determined the X-ray crystal structure of a dimeric Lac repressor bound to a 22 base-pair DNA with the natural operator O1 sequence and the anti-inducer ONPF, at 4.0 A resolution. The natural operator is bent in the same way as the symmetric sequence, due to the binding of the hinge helices of the repressor to the minor groove at the central GCGG sequence of O1. Comparison of the structures of the repressor bound to the natural and symmetric operators shows very similar overall structures, with only slight rearrangements of the headpiece domains of the repressor. Analysis of crystals with iodinated DNA shows that the operator is uniquely positioned and allows for the sequence registration of the DNA relative to the repressor to be determined. The kink in the operator is centered between the left half-site and the central G-C base-pair of O1. Our results are most consistent with a previously proposed model in which, relative to the complex with the symmetric operator, the repressor accommodates binding to the natural operator sequence by shifting the position of the right headpiece by one base-pair step towards the center of O1.

Peritoneal tuberculosis in patients receiving continuous ambulatory peritoneal dialysis

BACKGROUND

Patients with chronic renal failure have an increased risk of tuberculosis (TB). This occurs with much higher frequency within the first 12 months of initiating dialysis and is usually extrapulmonary in nature. Patients most at risk are those from susceptible ethnic groups, especially the Indian subcontinent. Peritoneal TB, otherwise relatively uncommon, has emerged as an important form of TB in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).

METHODS

All cases of peritoneal TB occurring at our institution in patients undergoing CAPD over a 13 year period were identified and analysed.

RESULTS

Eight cases were identified, of which seven were non-Caucasian. These patients' characteristics and outcomes are presented. All were undergoing CAPD and most developed TB within 12 months of initiating dialysis. All presented with fever, but symptoms and signs were indistinguishable from bacterial peritonitis. Six were culture-positive, mainly from peritoneal dialysis fluid, but only two cases proved smear-positive. All were treated with standard anti-tuberculous chemotherapy. Three went on to permanent haemodialysis as a result of peritonitis and three have died, one of these as a result of TB.

CONCLUSIONS

Peritoneal TB, whilst otherwise relatively uncommon, is an important manifestation of TB in CAPD patients and usually develops soon after commencing dialysis. The reasons for this are unknown and require further research.

The Lac repressor: a second generation of structural and functional studies

In the past year, the crystal structure of a dimeric version of the Escherichia coli Lac repressor bound to operator DNA was determined at 2.6A resolution, providing a closer view of the operator-bound conformation of the repressor. Refined NMR studies of the DNA-binding portion of the repressor complexed to operator DNA have revealed further details of the unique DNA-binding interactions of the repressor. The structural studies have been complemented by continued biochemical studies, with the overall goal of understanding the mechanism of allosteric regulation.

Crystal structure of the lambda repressor C-terminal domain provides a model for cooperative operator binding

Interactions between transcription factors bound to separate operator sites commonly play an important role in gene regulation by mediating cooperative binding to the DNA. However, few detailed structural models for understanding the molecular basis of such cooperativity are available. The c1 repressor of bacteriophage lambda is a classic example of a protein that binds to its operator sites cooperatively. The C-terminal domain of the repressor mediates dimerization as well as a dimer-dimer interaction that results in the cooperative binding of two repressor dimers to adjacent operator sites. Here, we present the x-ray crystal structure of the lambda repressor C-terminal domain determined by multiwavelength anomalous diffraction. Remarkably, the interactions that mediate cooperativity are captured in the crystal, where two dimers associate about a 2-fold axis of symmetry. Based on the structure and previous genetic and biochemical data, we present a model for the cooperative binding of two lambda repressor dimers at adjacent operator sites.

A closer view of the conformation of the Lac repressor bound to operator

Crystal structures of the Lac repressor, with and without isopropyithiogalactoside (IPTG), and the repressor bound to operator have provided a model for how the binding of the inducer reduces the affinity of the repressor for the operator. However, because of the low resolution of the operator-bound structure (4.8 A), the model for the allosteric transition was presented in terms of structural elements rather than in terms of side chain interactions. Here we have constructed a dimeric Lac repressor and determined its structure at 2.6 A resolution in complex with a symmetric operator and the anti-inducer orthonitrophenylfucoside (ONPF). The structure enables the induced (IPTG-bound) and repressed (operator-bound) conformations of the repressor to be compared in atomic detail. An extensive network of interactions between the DNA-binding and core domains of the repressor suggests a possible mechanism for the allosteric transition.

Oligomerization of a 45 kilodalton fragment of diphtheria toxin at pH 5.0 to a molecule of 20-24 subunits

Diphtheria toxin (DT) is a 58 kDa protein, secreted by lysogenic strains of Corynebacterium diphtheriae, that causes the disease diphtheria in humans. The catalytic (C) domain of DT kills host cells by gaining entry into the cytoplasm and inhibiting protein synthesis. The translocation of the C domain across the endosomal membrane and into the cytoplasm of a host cell is mediated by the translocation (T) domain of DT. This process is triggered by acidification from pH approximately 7 to pH approximately 5 within the endosome. Here we show that crm45 (cross-reacting material of 45 kDa), a 45 kDa deletion mutant of DT which contains the C and T domains but lacks the C-terminal receptor-binding (R) domain, undergoes a transition from a monomer to a large oligomer upon acidification from pH 7.0 to pH 5.0. Dynamic light scattering analysis of crm45 at pH 5.0 results in a polydispersity value of only 8-17%, suggesting that the oligomer is uniformly sized. Using analytical ultracentrifugation, measurements of the sedimentation rate and diffusion coefficient of crm45 at pH 5.0 result in a molecular mass determination of 890 +/- 40 kDa (20 +/- 1 subunits) for the oligomer. Equilibrium sedimentation data on crm45 at pH 5.0 are best fit by a single species with a mass of 1000 +/- 50 kDa (24 +/- 1 subunits). These results reveal the pH-dependent formation of a uniformly sized, 20-24 subunit oligomer of the C and T domains of DT, in solution. Because the oligomer of crm45 forms at the pH of the acidified endosome, it could be relevant to the translocation of the C domain of DT across the endosomal membrane and into the cytoplasm of host cells. The possible relevance of this oligomer of crm45 to the membrane translocation of the C domain of DT correlates with earlier kinetic studies of DT intoxication of Vero cells, which inferred the transfer of approximately 20 C domains of DT to the cytoplasm of host cells, in a single event.

Unusual conformation of nicotinamide adenine dinucleotide (NAD) bound to diphtheria toxin: a comparison with NAD bound to the oxidoreductase enzymes

The conformation of NAD bound to diphtheria toxin (DT), an ADP-ribosylating enzyme, has been compared to the conformations of NAD(P) bound to 23 distinct NAD(P)-binding oxidoreductase enzymes, whose structures are available in the Brookhaven Protein Data Bank. For the oxidoreductase enzymes, NAD(P) functions as a cofactor in electron transfer, whereas for DT, NAD is a labile substrate in which the N-glycosidic bond between the nicotinamide ring and the N-ribose is cleaved. All NAD(P) conformations were compared by (1) visual inspection of superimposed molecules, (2) RMSD of atomic positions, (3) principal component analysis, and (4) analysis of torsion angles and other conformational parameters. Whereas the majority of oxidoreductase-bound NAD(P) conformations are found to be similar, the conformation of NAD bound to DT is found to be unusual. Distinctive features of the conformation of NAD bound to DT that may be relevant to DT's function as an ADP-ribosylating enzyme include (1) an unusually short distance between the PN and N1N atoms, reflecting a highly folded conformation for the nicotinamide mononucleotide (NMN) portion of NAD, and (2) a torsion angle chi N approximately 0 degree about the scissile N-glycosidic bond, placing the nicotinamide ring outside of the preferred anti and syn orientations. In NAD bound to DT, the highly folded NMN conformation and torsion angle chi N approximately 0 degree could contribute to catalysis, possibly by orienting the C1'N atom of NAD for nucleophilic attack, or by placing strain on the N-glycosidic bond, which is cleaved by DT. The unusual overall conformation of NAD bound to DT is likely to reflect the structure of DT, which is unusual among NAD(P)-binding enzymes. In DT, the NAD binding site is formed at the junction of two antiparallel beta-sheets. In contrast, although the 24 oxidoreductase enzymes belong to at least six different structural classes, almost all of them bind NAD(P) at the C-terminal end of a parallel beta-sheet. The structural alignments and principal component analysis show that enzymes of the same structural class bind to particularly similar conformations of NAD(P), with few exceptions. The conformation of NAD bound to DT superimposes closely with that of an NAD analogue bound to Pseudomonas exotoxin A, an ADP-ribosylating toxin that is structurally homologous to DT. This suggests that all of the ADP-ribosylating enzymes that are structurally homologous to DT and ETA will bind a highly similar conformation of NAD.

Crystal structure of nucleotide-free diphtheria toxin

The crystal structure of diphtheria toxin (DT) in the absence of nucleotide (nucleotide-free DT) has been determined at 2.3 A resolution to a crystallographic R factor and free R factor of 18.2 and 28.2%, respectively. A comparison of this structure to the previously determined structures of DT in complex with adenyly(3'-5')uridine monophosphate (ApUp) and DT in complex with nicotinamide adenine dinucleotide (NAD) reveals that there are no significant movements of the two subdomains of the catalytic (C) domain associated with dinucleotide binding. The side chains of six residues within the active-site cleft, including Tyr65, Pro38, Tyr27, Thr23, Glu148, and Tyr54, show movements of up to 3 A upon dinucleotide binding. In the structure of nucleotide-free DT, the active-site loop residues 39-47 of the C domain are well ordered and extend over the active-site cleft in approximately the same position as in the structure of DT in complex with ApUp. This is in contrast to the structure of the DT-NAD complex, in which the active-site loop is disordered. On the basis of a comparison of the nucleotide-free and NAD-bound DT structures, we suggest that the interaction of NAD with Pro38 and also possibly Tyr54 and Trp153 could disrupt the network of hydrogen bonds that stabilizes the position of the active-site loop over the active-site cleft, allowing this loop to become disordered. This may be an important step in binding of the C domain of DT to its substrate, elongation factor-2.

Crystal structure of diphtheria toxin bound to nicotinamide adenine dinucleotide

The crystal structure of diphtheria toxin (DT) in complex with nicotinamide adenine dinucleotide (NAD) has been determined by x-ray crystallography to 2.3 A resolution. NAD binds to a cleft on the surface of the catalytic (C) domain of DT, interacting closely with the side chains of Tyr54, Tyr65, His21, Thr23, and Glu 48. The carboxylate group of Glu148 of Dt lies approximately 4 A from the scissile, N-glycosidic bound of NAD, suggesting a possible catalytic role for Glu148 in stabilizing a positively charged oxocarbonium intermediate. Residues 39-46 of the active-site loop of the C-domain become disordered upon NAD-binding, suggesting a potential role for these residues in binding to elongation facor-2 (EF-2). Structural alignments of the DT-NAD complex with the structures of other ADP-ribosylating toxins suggest how NAD may bind to these other enzymes.

Crystal structure of diphtheria toxin bound to nicotinamide adenine dinucleotide

Diphtheria toxin (DT), a 58 kDa protein secreted by lysogenic strains of Corynebacterium diphtheriae, causes the disease diphtheria in humans by gaining entry into the cytoplasm of cells and inhibiting protein synthesis. Specifically, the catalytic (C) domain of DT transfers the ADP-ribose group of NAD to elongation factor-2 (EF-2), rendering EF-2 inactive. In order to investigate how the C-domain of DT binds NAD and catalyzes the ADP-ribosylation of EF-2, the crystal structure of DT in complex with NAD has been determined to 2.3 A resolution. This is the first crystal structure of an ADP-ribosyltransferase (ADP-RT) enzyme in complex with NAD and suggests the features of the ADP-RT fold which are important for NAD binding. The conformation of NAD in the complex and the proximity of the Glu148 carboxylate group of the C-domain to the scissile, N-glycosidic bond of NAD suggest plausible modes of catalysis of the ADP-ribosylation reaction. Residues 39-46 of the active-site loop of the C-domain become disordered upon NAD binding, suggesting a potential role for this loop in the recognition of the ADP-ribose acceptor substrate, EF-2. The negatively charged phosphates and two ribose hydroxyls of NAD are not in direct contact with any atoms of the C-domain. Instead, they form an exposed surface which appears to be presented for recognition by EF-2. Structural alignments of the DT-NAD complex with the structures of other members of the ADP-RT family suggest how NAD may bind to these other enzymes.

A comparison of the effects of phenelzine treatment with moclobemide treatment on cardiovascular reflexes

The effects of treatment with phenelzine (n = 15) and moclobemide (n = 20) on heart rate variability and cardiovascular responses to standing were examined using non-invasive beat-to-beat blood pressure (BP) monitoring in an open cross-sectional study. Phenelzine markedly impaired the BP response compared with moclobemide, with 83% vs 15% of patients lacking the normal initial BP overshoot (p < 0.01). BP recovery to supine levels was delayed (median time for diastolic BP 14.5 s after phenelzine vs 4.9 s after moclobemide; p < 0.002). Standing BP at 1 min and its change from supine levels were also significantly lower in the phenelzine group (delta diastolic BP 4 mmHg vs 15 mmHg; p < 0.001). Heart rate responses and variability were preserved and did not differ between treatments. These findings are consistent with impairment of sympathetic function but preservation of parasympathetic responses after phenelzine treatment.

Outbreaks of syphilis in rural Texas towns, 1991-1992

Between 1986 and 1990, rates of primary and secondary syphilis increased 134% in rural counties in the South. Reasons for the increases are speculative. During the 14 months ending in October 1992, outbreaks in four eastern Texas counties provided an opportunity to characterize syphilis in rural Texas. We reviewed records for 118 patients and 339 sex partners. Three outbreaks were concentrated in neighborhoods where crack cocaine dealers conducted business and exchange of sex for drugs or money was common; the fourth outbreak involved out-of-town prostitutes who visited undocumented alien workers. Among the 118 syphilis cases, 15 (13%) were primary, 35 (30%) were secondary. Most patients were black (105, 89%); the male-female ratio was 1:1. One woman gave birth to an infant with congenital syphilis. Almost half of the sex partners were infected. HIV pretest counseling was completed for only 55 patients (47%), and only 23 (19%) were tested for the human immunodeficiency virus. These four rural outbreaks of syphilis associated with crack cocaine and the exchange of sex for drugs or money mirror recent urban syphilis outbreaks. Patients in these rural syphilis outbreaks are at risk for HIV infection, but HIV testing has not been emphasized by public health workers.

Comparative response of rainbow trout and rat to the liver mitogen, lead

Lead nitrate and acetate are potent liver mitogens in the Wistar rat. Prior exposure to these agents has been found to alter their susceptibility to hepatotoxins. The present study assessed the capacity of both lead compounds to cause mitogenicity in the liver of adult male and female rainbow trout. Groups treated with a single intravenous or intraperitoneal injection of lead nitrate or lead acetate exhibited no statistically significant (P < 0.05) alterations in liver/body weight ratio nor hepatic DNA content. Results provide evidence of significant interspecies variation in the mitogenic response of rainbow trout and Wistar rats to the mitogenic potential of lead in the liver.

Self-reported sexual behaviors of schizophrenic clients and noninstitutionalized adults

In this descriptive study the authors compare self-reported sexual behaviors of a group of hospitalized psychiatric clients with a group of noninstitutionalized adults. An interview method was used to obtain information about interest in sex, frequency of intercourse, and sexual satisfaction. Control group members and clients reported about the same interest in sex, frequency of intercourse, and satisfaction in their younger years. In their current lives, however, clients reported slightly less sexual feeling and a much lower frequency of intercourse. Nearly half of the clients were not having intercourse, with the majority of those attributing the reason as hospitalization. Concerns about normalizing the institutional environment for sexual expression for chronically mentally ill persons are discussed.

A comparative analysis of the health beliefs of older black males and females

The purpose of this study was to examine differences in the health beliefs of older Black males and females. The sample consisted of 66 respondents, 39 females and 27 males. The six variables measured in this study were current health perceptions, health concerns, resistance-susceptibility perceptions, health outlook and rejection of the sick role. The Health Perceptions Questionnaire (HPQ) developed by Ware (1976) and a demographic profile were utilized to collect data. The HPQ is a self administered instrument, consisting of 32 questions which are designed to obtain information relative to an individual's beliefs about various aspects of his/her health status. Internal consistency coefficients of the HPQ ranged from 0.70 to 0.92. Descriptive statistics were utilized to describe the sample. One-way analysis of variance was utilized to test each hypothesis. Results revealed rejection of all six hypotheses at p < 0.05 level.

The role of staff development in promoting BSN programs

Staff development is undergoing rapid change in the current health care environment. One issue of critical importance is providing access to credit courses for nurses who want to obtain a Bachelor of Nursing (BSN) degree. A university and hospital collaborated to provide learning opportunities jointly for nurses to work toward completion of a BSN using the off-campus concept.

Monoclonal antibodies to human neuron-specific enolase reveal heterogeneity of the enzyme in neurons of the central nervous system

Three monoclonal antibodies to human neuron-specific enolase (NSE) were used to survey the human brain and spinal cord for immunoreactivity. Two of the antibodies (EB and CF) recognized the same population of cells and cell processes. Reactivity was restricted to myelinated axons, basket cell bodies and processes, and a small population of pyramidal cell bodies in the visual cortex. The third antibody (AD) reacted with some, but not all, of the neuronal cell bodies in cerebral cortex, hippocampus, midbrain, and spinal cord. Many neurons did not react with any of the antibodies. The epitope recognized by AD was trypsin-sensitive, while those recognized by EB and CF were not. These studies suggest that NSE may have multiple conformational or structural forms which are segregated between the cell body and axon.

Acute intravascular hemolytic anemia in the black rhinoceros: hematologic and immunohematologic observations

To investigate the syndrome of acute intravascular hemolytic anemia in the black rhinoceros (Diceros bicornis), laboratory techniques used in the differential diagnosis of hemolytic anemias were performed on blood samples from 6 black rhinoceroses: 3 nonrelated healthy rhinoceroses, 1 rhinoceros with iron deficiency anemia, and 2 rhinoceroses with intravascular hemolysis. Osmotic fragility, erythrocyte membrane protein composition, hemoglobin electrophoresis, and hemoglobin stability did not distinguish between healthy and affected (anemia or hemolysis) rhinoceroses. Polyclonal antiglobulin reagents were prepared in rabbits, using whole rhinoceros serum and purified rhinoceros immunoglobulin G. These reagents were nonreactive against erythrocytes of the healthy and iron-deficient rhinoceroses. Reactions with RBC from the rhinoceros with fatal hemolytic anemia indicated increased membrane coating by the third component of complement; this was not evident in a second rhinoceros that survived a hemolytic event.

Serum levels of CA-125 in patients with endometriosis: a preliminary report

Seven out of 8 patients with endometriosis demonstrated levels of CA-125 antigen above 35 U/ml. None of 15 patients with other benign gynecologic diagnoses demonstrated elevated levels. This antigen has been proposed as a tumor marker for epithelial carcinoma and other gynecologic neoplasms. However, it cannot be used to differentiate clinically between cancer and endometriosis.

Thrombomodulin, an endothelial anticoagulant protein, is absent from the human brain

Protein C activation by thrombin is significantly accelerated by the endothelial cell cofactor, thrombomodulin. In this study, we have developed a radioimmunoassay for thrombomodulin and have measured the cofactor content in several human tissues. The assay method detects as little as 2 ng of thrombomodulin. The highest thrombomodulin content was found in lung and placenta, but the antigen was also detected in spleen, pancreas, liver, kidney, skin, heart, and aorta. Unexpectedly, thrombomodulin was absent from brain. Extracts from cerebral cortex, cerebellum, centrum semiovale, midbrain, basal ganglia, pons, and medulla were devoid of thrombomodulin. In contrast, thrombomodulin antigen is present in extracerebral intracranial vessels, including basilar and internal carotid arteries and choroid plexus, as well as in endothelium of the pia-arachnoid.

Thrombomodulin is found on endothelium of arteries, veins, capillaries, and lymphatics, and on syncytiotrophoblast of human placenta

We have used antibodies to human thrombomodulin isolated from placenta to investigate the distribution of this cofactor for protein C activation in human tissues. Thrombomodulin was found on endothelial cells of arteries, veins, capillaries, and lymphatics by immunocytochemical staining using an avidin-biotin peroxidase method. Thrombomodulin was not detected on sinusoidal lining cells of liver or on postcapillary high-endothelial venules of lymph node, although the latter contained another endothelial antigen, von Willebrand factor. Other cells noted to contain thrombomodulin antigen are those of the syncytiotrophoblast in placenta. The thrombomodulin in syncytiotrophoblast was primarily on the plasma membrane surface that forms the maternal blood sinus. Syncytiotrophoblast also stained with antibodies to von Willebrand factor, which implies that these cells have multiple endothelial functions. Thrombomodulin antigen was found in all organs studied, with the notable exception of brain.

Preparation and characterization of monoclonal antibodies to human neuron-specific enolase

Neuron-specific enolase (NSE) has been increasingly recognized as a marker for neuroendocrine tumors including small cell carcinoma of the lung (SCCL). To prepare monoclonal antibodies (MAbs) specific for human NSE, we first developed a simple method of purifying NSE by direct chromatofocusing of a crude extract of human brain tissue. BALB/c mice were then immunized with our preparation of NSE, and MAbs against NSE were generated utilizing a hybridoma technique. The antibodies were screened against both NSE and non-neuronal enolase (NNE) by a solid-phase radioimmunoassay (SPRIA). After cloning and subcloning of hybridomas, two groups of anti-NSE MAbs were identified by SPRIA. One group reacted specifically with NSE but not with its isoenzyme NNE, irrespective of whether antigens were glutaraldehyde fixed or unfixed. A second group reacted with both NSE and NNE when the latter were glutaraldehyde fixed, but surprisingly with neither antigen in the absence of fixation. Group I antibodies were further characterized by immunoblotting, and by immunocytochemistry of normal brain and liver sections and sections of SCCL. The results further supported the specificity of group I antibodies for NSE. These MAbs have potential utility in the diagnosis and management of neuroendocrine tumors, and in further understanding the biology of NSE.

Intestinal pseudo-obstruction as the presenting manifestation of small-cell carcinoma of the lung. A paraneoplastic neuropathy of the gastrointestinal tract

A 58-year-old woman who had presented with intestinal pseudo-obstruction died 9 months later from rapidly progressive neurologic symptoms and autonomic insufficiency. Her gastric emptying had been markedly delayed and transit of markers had been slowed throughout the small bowel. A 5-hour manometric recording of the antrum and duodenum had shown absence of the normal interdigestive motor complex, which was replaced by irregular contractile activity of reduced amplitude. A small-cell carcinoma of the lung was found at autopsy. Pathologic study of the gut showed widespread degeneration of the myenteric plexus, which was infiltrated by plasma cells and lymphocytes and contained significantly reduced numbers of neurons. The extra-intestinal nervous system had neuronal loss and lymphocytic infiltrates in dorsal root ganglia. Thus, a gastrointestinal neuropathy causing intestinal pseudo-obstruction may be the presenting manifestation of a paraneoplastic syndrome associated with small-cell carcinoma.

Pulmonary oat cell carcinomas. Expression of plasma membrane antigen correlated with presence of cytoplasmic neurosecretory granules

A plasma membrane antigen highly associated with pulmonary oat cell carcinoma has recently been identified. Expression of this surface antigen was now examined in routine surgical pathology material from 32 primary lung tumors by immunostaining. The staining patterns of 17 tumors diagnosed as oat cell carcinoma by light microscopy were compared to those of 10 epidermoid carcinomas, four carcinoid tumors, and one lymphocytic lymphoma. In addition, when available, the oat cell carcinoma group was also studied by electron microscopy for demonstration of cytoplasmic neurosecretory granules. Twelve of the 17 oat cell carcinomas and one of the epidermoid carcinomas expressed the antigen. In this group of small cell tumors of the lung, aggrement was found between the expression of this immunochemical marker and the presence of neurosecretory granules in the cytoplasm of the tumors. Demonstration of this surface antigen in routine surgical pathologic material may be a useful aid in the diagnosis of these tumors. The failure of a group of tumors, which satisfied the light microscopic criteria for oat cell carcinoma to stain for the antigen, demonstrates heterogeneity within the oat cell carcinoma group.

Identification of the Schwann cell as a peripheral nervous system cell possessing a differentiation antigen expressed by a human lung tumor

Recent studies of the plasma membrane antigens of a human lung tumor (oat cell carcinoma) indicated that the tumor expressed at least two normal differentiation antigens undetectable in normal respiratory epithelium. One antigen was characteristic of certain endodermally derived epithelial cells of the digestive system; the other antigen was characteristic of certain neural crest-derived cells in the peripheral nervous system. The present studies were undertaken to identify the reactive cell type in the peripheral nervous system. Since similar cells in the rat peripheral nervous system expressed a cross-reactive form of this antigen, and since pure cultures of different rat nerve cell type were available, the following approach was possible. Cultures of pure neurons, pure Schwann cells, pure fibroblasts, neurons and Schwann cells, and neurons, Schwann cells, and fibroblasts were assayed for this antigen with rabbit anti-oat cell carcinoma plasma membrane antiserum absorbed with normal lung and liver. The indirect immunofluorescence method on both whole, viable cell and fixed cell substrates was used. Only Schwann cells expressed the antigen; Schwann cells in the presence of neurons expressed the antigen much more strongly than did pure Schwann cells. It was concluded that the oat cell carcinoma of the lung expressed a differentiation antigen present on Schwann cells.

Human beta-glucuronidase deficiency mucopolysaccharidosis: identification of cross-reactive antigen in cultured fibroblasts of deficient patients by enzyme immunoassay

An enzyme immunoassay for human beta-glucuronidase was developed to determine the presence or absence of antigenically cross-reactive material (CRM) in patients with beta-glucuronidase deficiency mucopolysaccharidosis. This assay provided a sensitive means of measuring the primary interaction between the enzyme molecule and antibody but required neither pure antigen nor monospecific antiserum, an important consideration, since neither of these was available. Goat antiserum to partially purified human placenta beta-glucuronidase did not recognize differences in normal enzyme from human placenta, liver, fibroblasts, or blood platelets. CRM was identified in fibroblast extracts from all four of the unrelated beta-glucuronidase-deficient patients studied, but titration patterns indicated genetic heterogeneity among these four mutant proteins. Fibroblast enzymes from two obligate heterozygotes were distinguishable immunologically from normal enzyme. The enzyme immunoassay was also used to compare human enzyme with liver enzyme from other mammalian species. CRM was present in liver extracts of all species tested, but the liver enzymes, except for the rabbit, were weakly cross-reactive. We conclude that despite certain limitations, the enzyme immunoassay for human beta-glucuronidase is useful and that all four beta-glucuronidase-deficient patients studied possess CRM.

HLA in primary open-angle glaucoma

Histocompatibility antigen typing was carried out in 50 Caucasian patients with primary open-angle glaucoma (POAG) and 50 Caucasian ocular-normotensive subjects. HLA-A 3 was present in 46%, B7 in 52%, B12 in 50%, and either B7 or B12 in 88% of p,tients with POAG. These prevalences in POAG patients were significantly greater than in ocular-normotensive subjects (p less than 0.01, p less than 0.0005, p less than 0.001, and p less than less than 0.0005, respectively). The prevalences of A 3-B 7, A 3-B 12 and either combination were also significantly greater in POAG patients than in the ocular normotensives (p less than 0.005, p less than 0.005, and p less than 0.0005, respectively). HLA-BW 35 was noted to be in deficit in Caucasian POAG patients (8%) as compared to Caucasian ocular normotensives (32%; p less than 0.01).

A plasma membrane antigen highly associated with oat-cell carcinoma of the lung and undetectable in normal adult tissue

The plasma membrane antigens of an oat-cell carcinoma of the lung were studied to determine if any antigens absent from normal adult tissue could be identified. Rabbit and monkey antisera were prepared to a highly purified plasma membrane fraction of an oat-cell carcinoma of the lung. The specificities of the antisera were studied by the indirect immunofluorescence method on frozen section substrate. The rabbit antiserum, after absorption with normal lung, liver, colon and peripheral nerve homogenates and extracts, failed to react with any detectable normal adult tissue. The absorbed anti-serum did react with 7 of 7 oat-cell carcinomas of the lung, but failed to react with any of 7 adeno-carcinomas of the lung, 6 epidermoid carcinomas of the lung, 7 colon carcinomas, 8 breast carcinomas, 4 kidney carcinomas, and 1 pancreatic carcinoma. The unabsorbed monkey antiserum failed to react with any detectable normal adult tissue, and had a tumor reactivity pattern nearly identical to that of the absorbed rabbit antiserum. Thus similar results were obtained with antisera from two different species. It is concluded that oat-cell carcinomas of the lung express a plasma membrane antigen(s) undetectable in normal adult tissue and highly associated with this tumor type.

Endodermally-derived and neural crest-derived differentiation antigens expressed by a human lung tumor

The plasma membrane antigens of an undifferentiated small cell (oat cell) carcinoma of the lung were studied by the indirect immunofluorescence method on frozen section substrates with a rabbit antiserum prepared to the tumor plasma membrane fraction. After appropriate absorption of the antiserum, at least two differentiation antigens present on the tumor cells but undetectable on normal lung surface or glandular epithelial cells were identified. One antigen(s) was characteristic of certain normal, endodermally-derived epithelial cells of the digestive system, including those of colonic mucosa, hepatic ducts, pancreatic ducts and acini, and islets of Langerhans. The other antigen(s) was characteristic of certain normal, neural crest-derived cells in the peripheral nervous system, including cells in peripheral nerve, dorsal root ganglion, and anterior roots of the spinal cord; parasympathetic ganglion cells in the colon; and small nerves and nerve processes in the lung, colon, and skin. It was concluded that the presence of these differentiation antigens on the tumor cells resulted from the expression of gene products repressed in the normal cell of origin of the tumor.

A normal adult and fetal lung antigen present at different quantitative levels in different histologic types of human lung cancer

Rabbits were immunized with extract of either an adenocarcinoma of the lung, or one of three oat cell carcinomas of the lung. Unabsorbed and variously absorbed antisera, and various extracts, were analyzed by double and radial immunodiffusion. The adenocarcinomas-antisera identified an antigen subsequently quantitated at high concentration in seven adenocarcinomas of the lung, but a low concentration in five normal adult and four fetal lungs. Three of four epidermoid carcinomas of the lung contained the antigen at low concentration, however only trace amounts were detected in four of five oat cell carcinomas of the lung. The oat cell carcinoma-antisera failed to identify a significant antigen. Quantitatively, the above antigen appeared to distinguish adenocarcinomas and to a lesser extent epidermoid carcinomas from oat cell carcinomas of the lung, and to be consistent with the concept that oat cell carcinomas arise from a different cell type than the other lung tumors.

Shock Wave Generation in Air and in Water by CO(2) TEA Laser Radiation

Shadowgraph techniques, using a Q-switched ruby laser as a light source, have been used to examine the shock waves produced in air and in water by focusing CO(2) TEA laser radiation at an air-water interface. It is found that the shock speed in water decays to the sound speed within 0.5 microsec, while the shock speed in air persists at values higher than the sound speed for times long compared to 0.5 microsec.