Response to intravenous midazolam sedation in general dental practice

The object of this study was to grade the response of patients undergoing a variety of dental procedures with the aid of intravenous midazolam sedation in general dental practice and to explore any relationships between the patients preoperative anxiety assessment and the clinician's assessment of co-operation whilst under sedation. One hundred consecutive patients aged between 18 and 58 years (mean 32 years; sd 10 years) and in ASA Class I or II were prospectively studied. Results showed that despite attempts to grade patient's behaviour it was not possible to reliably predict patient's responses under intravenous sedation. In addition to these findings, the great individual variation in sensitivity to midazolam was confirmed.

An unusual but important cause of sciatica

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From relief to development: the long-term effects of 'temporary' accommodation on refugees and displaced persons in the Republic of Croatia

The increasing scale of international intervention in conflict is generating new pressures on the humanitarian community. Increased expenditure on emergency relief, static levels of overseas development aid and subsequent lack of funds for development are dictating that agencies design relief projects that positively effect developmental reconstruction. This paper examines the provision of shelter for refugees and displaced persons in the Republic of Croatia and identifies ways in which it has encouraged and discouraged sustainable reconstruction. It argues that to promote lasting reconstruction, programmes must focus on saving livelihoods as well as lives, thus minimising the long-term psychological and physical impacts of aid on refugees, displaced persons and host communities.

Researching under fire: issues for consideration when collecting data and information in war circumstances, with specific reference to relief and reconstruction projects

The post-Cold War era has witnessed an increased number of conflicts and higher levels of international intervention by the humanitarian community and the military. Those who undertake to research the actions of relief and development agencies acting in these wars must act within new parameters that require a flexible, innovative and reflective approach. Not much is known about data collection in war. The most relevant publications come from the field of development studies. This paper is a beginning in a much-needed discourse on researching under fire; it is offered not as a definitive work, but as a starting-point for discussion.

Stray RF field strength during radiofrequency endometrial ablation

A study has been carried out of the RF field strength around a total of 17 patients undergoing radio-frequency endometrial ablation in three hospital centres. The mean equivalent power density at the position of the surgeon exceeded 10 W m-2, which is the derived investigation level for exposure to electromagnetic fields. This value is derived from a basic restriction in the average specific absorption rate in the body to 0.4 W kg-1. This limit applies to general population as well as occupational exposure and is well below that which has been shown to be hazardous to health. Also, the working conditions did not place physical stress on the surgeon. The maximum value of the specific energy absorption rate in the head or trunk should not exceed 10 W kg-1. Measured values on the field strength suggest that this organ dose limit was not exceeded. It is concluded that staff exposure to stray RF radiation during radio-frequency endometrial ablation is not considered to be hazardous to health.

Extracellular truncations of h beta c, the common signaling subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and IL-5, lead to ligand-independent activation

The hypothesis that extracellular truncation of the common receptor subunit for interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 (h beta c) can lead to ligand-independent activation was tested by infecting factor-dependent hematopoietic cell lines with retroviruses encoding truncated forms of h beta c. A truncation, resembling that in v-Mpl, and retaining 45 h beta c-derived extracellular residues, led to constitutive activation in the murine myeloid cell line, FDC-P1. However, infection of cells with retrovirus encoding a more severely truncated receptor, retaining only 7 h beta c-derived extracellular residues, did not confer factor independence on these cells. These experiments show that truncation activates the receptor and define a 37-amino acid segment of h beta c (H395-A431) which contains two motifs conserved throughout the cytokine receptor superfamily (consensus Y/H XX R/Q VR and WSXWS), as essential for factor-independent signaling. The mechanism of activation was also investigated in less severe truncations. A receptor that retains the entire membrane-proximal domain (domain 4) also conferred factor independent growth on FDC-P1 cells; however, a retrovirus encoding a truncated form of h beta c having two intact membrane proximal domains did not have this ability, suggesting that domain 3 may have an inhibitory role in h beta c. The ability of these receptors to confer factor independence was cell specific as demonstrated by their inability to confer factor-independent growth when introduced into the murine IL-3-dependent pro-B cell line BaF-B03. These results are consistent with a model in which activation requires unmasking of an interactive receptor surface in domain 4 and association with a myeloid-specific receptor or accessory component. We suggest that in the absence of ligand intramolecular interactions prevent inappropriate signaling.

Denial of hemiplegia: an investigation into the theories of causation

A comprehensive study of denial of hemiplegia, with tests chosen to cover the varied proposed hypotheses, was undertaken. Twenty patients with denial of hemiplegia following acute CVA were studied. Their results were compared with those from two patient 'control' groups. A neurological examination and neuropsychological assessment were carried out in all patients and CT brain scan performed in 21 CVA cases. The findings are discussed in relation to previously proposed theories of causation concerning denial of hemiplegia which include personality factors, cognitive ability and the presence/absence of neurological deficits. CT scan analyses showed that patients with denial of hemiplegia have significantly more white matter involvement, particularly the corona radiata, than those with neglect and there was also a trend that patients with denial are more likely to have lesions in the caudate.

Solution properties and computational analysis of an oligodeoxynucleotide containing N-(deoxyguanosin-8-yl)-1-aminopyrene

An oligodeoxyribonucleotide 5'-d(CTCATGAPATTCC), in which G(AP) denotes N-(guanin-8-yl)-1-aminopyrene, the C8-guanine adduct of reductively activated 1-nitropyrene, was synthesized and characterized by polyacrylamide gel electrophoresis, absorption and fluorescence spectroscopy, circular dichroism, and thermal melting studies. Polyacrylamide gel electrophoresis showed slower mobility of the adducted oligonucleotide in single-stranded form compared to its unmodified counterpart, as expected. In duplex form, however (with a deoxycytidine opposite the adduct), the adducted 11mer migrated faster than the parent duplex. Absorption and fluorescence studies indicated significant interaction of the aminopyrene residue with the DNA bases in the modified 11mer. The spectroscopic data also suggested the presence of one or more conformers in which the aminopyrene residue is quasi-intercalative, as well as one(s) in which the aminopyrene is externally bound. Thermodynamic parameters for the helix-to-coil transitions for the 11mer duplex were determined. The difference in free energy (delta delta G degree) between the unmodified and modified sequences was relatively small (approximately 1.2 kcal/mol). Circular dichroism spectra indicated the presence of essentially B-form DNA. The energy minimizations suggested that the most stable conformers shared a common feature: displacement of the modified guanine from the double helix. In the global minimum, the aminopyrene residue was inserted in the helix in the site of displaced guanine. In other low energy structures, the aminopyrene was also displaced towards the minor groove (in addition to guanine), or partly inserted and partly in the groove. More conventional structures were also encountered, with anti-guanine within the helix and aminopyrene in the major groove, or syn-guanine within the helix, and aminopyrene in the minor groove. Such structures were 12-20 kcal/mol less stable than the global minimum, however. The C8-guanine adduct of aminopyrene thus appears to perturb the B-DNA structure to a greater extent than do the adducts of less bulky amines such as aminofluorene and 4-aminobiphenyl.

Physician training for patient-centered nutrition counseling in a lipid intervention trial

BACKGROUND

We examined the effect of a 3-hr training program on physicians' lipid intervention knowledge, attitudes, and skills. The program teaches physicians skills to conduct a brief dietary risk assessment and provide patient-centered counseling to enable patients with elevated lipids to change their dietary patterns.

METHOD

The training is part of a randomized trial of lipid-lowering interventions, the Worcester Area Trial for Counseling in Hyperlipidemia. Primary care internists practicing in a health maintenance organization (HMO) were assessed, before and after training using questionnaires and audiotapes to document changes in knowledge about diet, attitudes about intervention, reported nutrition intervention practices, and counseling and assessment skills. Physicians also rated the value that they thought the training program had to them.

RESULTS

After completion of the program the physicians' use of dietary counseling steps, as assessed by blinded evaluation of audiotaped physician-patient interactions, significantly increased (mean pre = 5.4, mean post = 9.2; t = 9.9; P < or = 0.001). In this regard, there were instances in the use of 7 of the 14 specific counseling steps. Physicians also demonstrated increases in self-perceived preparedness as measured by a 5-point scale (mean pre = 3.2, mean post = 4.0; t = 4.25; P < 0.001), confidence in having an effect (mean pre = 3.3, mean post = 3.9; t = 3.16; P < 0.01), perception that materials were available to aid intervention (mean pre = 2.7, mean post = 4.0; t = 5.29; P < 0.001), and perception that they have access to a nutritionist (mean pre = 3.5, mean post = 4.0; t = 2.63; P < 0.01). They rated the value of the program between very good and excellent.

CONCLUSION

Results of this 3-hr educational program indicate that physicians in an HMO are responsive to the teaching of specialized skills deemed important for promoting health behavior change in their patients.

Microwaves for menorrhagia: a new fast technique for endometrial ablation

Current ablative techniques for treating menorrhagia are unsatisfactory. We tried microwave energy, delivered by an 8 mm diameter probe in the uterine cavity, to treat 23 patients with functional menorrhagia. The mean treatment time was 2 min 12 s (range 50-310 s). 6 months after treatment the success rate is 83%, 13 patients (57%) are amenorrhoeic, and six (26%) are experiencing light menstruation. Three initial failures have been successfully retreated. The technique is safe, and is easier and quicker to perform than current alternatives.

Plasminogen activators augment endothelial cell organization in vitro by two distinct pathways

Endothelial cell differentiation into capillary structures is a complex process that requires the concerted effects of several extracellular matrix proteases, including plasminogen activators. Here, the role of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) was evaluated in an in vitro model of endothelial morphogenesis involving organization of human umbilical vein endothelial cells into tubular structures when they are cultured on the basement membrane preparation, Matrigel. Both uPA and tPA were detected in HUVEC cultures on Matrigel, and inhibitors of plasminogen activators or of serine proteases decreased the extent of the tube network formed by the cells. The decrease resulting from serine protease inhibitors was additive to that from matrix metalloproteinase inhibitors which have previously been shown to decrease tube formation in this model, suggesting that the two classes of proteases modulate tube formation by distinct mechanisms. Plasminogen activator inhibitor (PAI)-1 decreased tube formation by 50% when added up to 4.5 h after the initiation of an 18 h assay and caused 25% inhibition when added 9.5 h after culture initiation, indicating that the effects of plasminogen activators are not limited to an early event in the differentiation process. Steady-state expression of mRNA for uPA increased during the first several hours of culture on Matrigel, further supporting a role for PA activity throughout the process of tube formation. These findings suggested that PAs may affect multiple events during tube-forming activity. A fucosylated peptide comprising the amino-terminal domain of uPA that binds to the uPA receptor (uPAR) but lacking proteolytic activity enhanced tube formation. In contrast, a defucosylated form of the same peptide had no effect. Since fucosylation of this fragment has been shown to be essential in other models of cell stimulation by uPA-uPAR interaction, these data support the hypothesis that uPA enhances endothelial morphogenesis both through proteolytic activity and via uPAR occupancy. Plasminogen activators could facilitate angiogenesis in vivo.

Immunization with class I human histocompatibility leukocyte antigen can protect macaques against challenge infection with SIVmac-32H

OBJECTIVE

To evaluate the efficacy of immunopurified class I human histocompatibility leukocyte antigen (HLA) to protect against SIV infection.

METHODS

HLA class I antigens were immunopurified from a human B-lymphoblastoid cell line. Groups of four macaques were vaccinated subcutaneously with four doses of the immunogen in adjuvant, or with adjuvant alone and subsequently challenged intravenously with 10 median monkey infectious doses of cell-free SIVmac-32H. Infection was determined by polymerase chain reaction for SIVmac proviral DNA and by virus isolation. Antigen-specific humoral and cellular immune responses were monitored.

RESULTS

Macaques immunized with the HLA molecules produced anti-HLA class I antibodies that inhibited SIV replication in vitro and downregulated autologous T-cell proliferation against irradiated C8166 cells. They were partially protected (two out of four) from virus infection for at least 33 weeks when challenged with SIV grown in human cells. All four control animals were infected.

CONCLUSIONS

This demonstration of partial protection, together with our previous work reporting that vaccination with allogenic cynomolgus lymphocytes can protect against challenge infection with SIV grown in simian cells, suggests that allogenic immune response induced before or during establishment of HIV infection may have important implications for AIDS disease progression.

Major and minor groove conformations of DNA trimers modified on guanine or adenine by 4-aminobiphenyl: adenine adducts favor the minor groove

We have studied the conformational effects of 4-aminobiphenyl modification at C-8 of guanine or adenine on double-stranded DNA trimers. We used sequences with the modified purine at the central base pair and all 16 possible neighboring sequences at the outer pairs. Minimized potential energy calculations were carried out using the molecular mechanics program DUPLEX to survey the conformation space of these adducts, using a total of 1280 starting structures both in the modified guanine series and in the modified adenine series. Conformer families in which the bound 4-aminobiphenyl was located in the DNA major groove, and in the minor groove, were located for both adenine and guanine modification. In the modified guanine series, the major and minor groove families were roughly comparable in energy, and the sequence context determined which was more stable in a particular case. In the modified adenine series, however, the minor groove structure was more than 10 kcal/mol more stable than the major groove structure for all sequences. As a result, minor groove adducts provided most of the global minima in the adenine-modified series. This result may be relevant to a previous mutagenesis study [Lasko et al. (1988) J. Biol. Chem. 263, 15429-15435] in which the hot spot of most frequent occurrence was located at an adenine, in the sequence GAT.

Left visuo-spatial neglect can be worse in far than in near space

We tested five patients with marked left-sided visuo-spatial neglect and two control subjects on a test of line bisection. A series of horizontal lines was presented to each subject, who had to indicate the centre with a projection light-pen. All five patients misplaced the centre to the right, in accordance with their left-sided neglect. However, in all five the angular displacement was greater for lines well beyond reach, than for lines of identical angular size within reaching distance. This result, precisely because it is opposite to that of a previous report, supports the conclusion that there are separate dissociated neural systems concerned with the perception of, and response to, stimuli in near and far space.

Polymorphism of bovine MHC class I genes. Joint report of the Fifth International Bovine Lymphocyte Antigen (BoLA) Workshop, Interlaken, Switzerland, 1 August 1992

The objectives of the Fifth International BoLA Workshop were to: standardize nomenclature, compare typing methods, and characterize BoLA haplotypes. The workshop was based on the distribution of blood samples (cells) from 60 selected cattle to 14 laboratories. Results for the class I (BoLA-A) region are presented in this paper while results for the class II regions are presented in a separate report. Thirty-six of the 50 previously established serological class I specificities were represented in the cell panel. However, only 30 specificities could be confirmed. Two specificities, A16 and A32, were upgraded from provisional, workshop (w) specificities to BoLA-A locus specificities and three new specificities, w51(w28), w52 and w53(w28), were defined. The 39 specificities distinguished 30 class I haplotypes in the 60 animals. Class I isoelectric focusing proved to be a useful adjunct to the serology. Isoelectric focusing confirmed several serologically defined splits and detected splits of A15(A8), A18(A6) and A22(w49) that had not been detected by serology. Subsequently, serological support for splits of A15(A8) and A22(w49) was found.

How lateralised is visuospatial neglect?

Seventeen patients with left visuospatial neglect caused by cerebral infarction undertook the six subtests of the Behavioural Inattention Test (BIT) as soon as possible following their neurological event. The group mean results on line, letter and star cancellation tasks revealed a linear decrement in performance from right to left on the displays. However, subsequent analysis of patients' cancellations revealed that this finding was not representative of individual performance. Many patients in fact made both marked left- and right-sided omissions on the three cancellation tasks. This was not merely a transitory phenomenon because it remained present at weekly follow-up intervals. Patients' performance on a laterally extended version of the star cancellation task was also investigated. These findings strongly suggest that patients with visuospatial neglect can initially present with a diverse range of performance deficit. Many patients, in particular those with the lowest BIT scores, showed a consistent pattern in the results on letter and star cancellation, providing evidence that their inattention consistently included a considerable section of right-sided (including the extreme right of displays) as well as left-sided space.

Brief remission periods in visuospatial neglect: evidence from long-term follow-up

Ten patients with left-sided visuospatial neglect due to cerebrovascular accident were monitored using the Behavioural Inattention Test (BIT) at weekly intervals, on a long-term basis. The novel finding was that some patients showed occasional but transitory marked improvement in their visuospatial neglect at times producing a normal score. This spontaneous phenomenon was evidenced by the patient cancelling sections or the entire block of left-sided targets, without any additional cues or prompts. Such episodes indicate that, in this small group of patients, visuospatial neglect is not necessarily irrevocable, at least for simple stimuli.

Cardiovascular studies of phenylpropanolamine

Phenylpropanolamine is found in a number of over-the-counter preparations commonly used for appetite control or as a cold remedy. Even though widely used, some questions still exist as to its effect on the cardiovascular system of man. Both anesthetized and unanesthetized adult beagle dogs were used in this study. In the unanesthetized conditioned dog, blood pressure and heart rate were measured using an inflatable tail cuff. In the first group, consisting of 12 dogs, phenylpropanolamine was given (0.0, 3.1, 6.25 and 12.5 mg/kg) via a stomach tube and the animals were followed for 300 minutes. Each dose of phenylpropanolamine was given to 4 groups made up of 3 dogs each. It produced dose-dependent increases in blood pressure and decreases of heart rate. Maximum changes were noted at 30 to 60 minutes, lasting for 3 to 5 hours. A second group of 9 unanesthetized dogs was given repeated oral doses of phenylpropanolamine (3 groups of 3 animals each). Doses of 3 mg/kg and 6 mg/kg, given orally, produced approximately the same increase in blood pressure and decrease of heart rate as previously observed. At 6 hours, these same doses of phenylpropanolamine produced little or no change in either parameter. At 24 hours after the first dose, however, the dogs responded in much the same manner as with the first administration of phenylpropanolamine. Control dogs given water did not exhibit any degree of tachyphylaxis. Dogs anesthetized with Na pentobarbital were given oral and intravenous doses of phenylpropanolamine (0.0-25 mg/kg). The overall response was like that observed in the unanesthetized preparation with the important exception that low doses (0.1-3 mg/kg) produced significant increases in both heart rate and blood pressure, while higher doses (6-25 mg/kg) resulted in a lesser overall effect. Six anesthetized animals were used to study the effects of phenylpropanolamine and norepinephrine on the cardiovascular function. Both the increase in blood pressure and left ventricular force of contraction, produced by the first dose of phenylpropanolamine, were markedly reduced or absent with the second administration of the drug. In addition, the classic blood pressure response to norepinephrine was likewise increased by prior administration of phenylpropanolamine.(ABSTRACT TRUNCATED AT 400 WORDS)

Fate of lesion-related side branches after coronary artery stenting

OBJECTIVES

The aim of this study was to assess the immediate and long-term patency of lesion-associated side branches after coronary artery stenting.

BACKGROUND

The possible adverse effects related to implantation of coronary stents are not completely known. An important potential complication of stenting is side branch occlusion due to mechanical obstruction or thrombosis.

METHODS

Serial coronary angiography was performed in 153 patients (167 lesions) at baseline, after conventional balloon angioplasty, immediately after Palmaz-Schatz stent placement and at 6 months. The patency of side branches, where present, was analyzed at each of these points.

RESULTS

Of 167 lesions stented, 57 stent placements spanned 66 side branches with a diameter > or = 1 mm. Twenty-seven (41%) of these side branches had > or = 50% ostial stenosis before standard balloon angioplasty. Six side branches became occluded after standard balloon angioplasty and remained occluded after stenting. Of the 60 side branches patent after conventional angioplasty, 57 (95%) remained patent immediately after stenting. All three side branches that became occluded after stenting had > or = 50% ostial stenosis at baseline. All 60 side branches, including the 3 initially occluded after stenting, were patent at 6-month follow-up.

CONCLUSIONS

These findings demonstrate that 1) acute side branch occlusion due to coronary stenting occurs infrequently; 2) when side branch occlusion occurs, it is associated with intrinsic ostial disease; and 3) the patency of side branch ostia is well maintained at long-term follow-up.

Typing of strains from a single-source outbreak of Pseudomonas pickettii

Plasmid profiles, genome restriction fragment polymorphisms, carbohydrate oxidation-fermentation reactions, methylumbelliferyl substrate hydrolysis patterns, antimicrobial susceptibilities, and results obtained with the Biolog GN biochemical substrate kit were used to type 19 common-source, but mixed-biotype, outbreak strains and one epidemiologically distinct strain of Pseudomonas pickettii. Biotyping with conventional and methylumbelliferyl substrates failed to distinguish between strains. Plasmid profile testing was found to be inconsistent and not reproducible. The Biolog GN kit allowed greater strain differentiation than restriction fragment polymorphism did (12 biotypes versus 5 biotypes); antimicrobial susceptibility testing yielded 4 biotypes, and oxidation-fermentation tests gave 3 biotypes. Oxidation-fermentation results were consistent with restriction fragment polymorphs in all but 1 of the 20 strains tested. For ease of typing, comprehensive typeability, and reproducibility, oxidation-fermentation tests should be performed initially and followed if necessary by restriction fragment polymorph analysis for the elucidation of P. pickettii infection outbreaks.

Lower extremity muscle thickness during 30-day 6 degrees head-down bed rest with isotonic and isokinetic exercise training

Muscle thickness was measured in 19 bed-rested (BR) men (32-42 year) subjected to isotonic (ITE, cycle ergometer) and isokinetic (IKE, torque ergometer) lower extremity exercise training, and no exercise (NOE) training. Thickness was measured with ultrasonography in anterior thigh--rectus femoris (RF) and vastus intermedius (VI), and combined posterior leg--soleus, flexor hallucis longus, and tibialis posterior (S + FHL + TP)--muscles. Compared with ambulatory control values, thickness of the (S + FHL + TP) decreased by 9%-12% (p < 0.05) in all three test groups. The (RF) thickness was unchanged in the two exercise groups, but decreased by 10% (p < 0.05) in the NOE. The (VI) thickness was unchanged in the ITE group, but decreased by 12%-16% (p < 0.05) in the IKE and NOE groups. Thus, intensive, alternating, isotonic cycle ergometer exercise training is as effective as intensive, intermittent, isokinetic exercise training for maintaining thicknesses of rectus femoris and vastus intermedius anterior thigh muscles, but not posterior leg muscles, during prolonged BR deconditioning.

HIV awareness at work

Shared personal and professional awareness of and commitment to HIV issues in employment prompted Sue Ellis and Liz Smart to set up a project which, through collaborative working between health promotion, personnel functions and trade unionists, would devise training materials to address employment issues and reduce concern about HIV infection in the workplace.

The recording and analysis of EMG and jaw tracking. II. Reproducibility of jaw tracking

In 10 male and 10 female adults jaw movements and muscle activity were monitored during chewing. Subjects had a Class I occlusion and fluent unrestricted jaw movements; non exhibited signs or symptoms of craniomandibular disorders. Recordings were made on two occasions separated by 2 weeks. Within each recording session the subjects carried out a number of tasks under direction, including eating nuts and gum. The jaw movements were monitored with a Sirognathograph which had been interfaced to a computer for data logging and analysis. A computer program identified each chewing stroke and after scrutiny a data base was constructed of measurements from a subset of 4447 suitable strokes. Mean values of 10 parameters selected to describe jaw movements during chewing were entered into an ANOVA. This indicated that the major contribution to variance was due to the subject from whom the data was recorded. This intersubject variability is well known, but can its separation from the other contributions to the variation within the data be assessed? To provide an estimate of the spread of data the variance for each parameter was calculated, transformed and these values entered into an analysis of variance. All subject differed significantly in their chewing movements from one another. But 15 of the 20 subjects showed a greater degree of consistency than the other five: they exhibited good inter- and intra-recording reproducibility. The food being eaten made a major contribution to the variability. The timing of the chewing strokes was also more consistent than the dimensions of the chewing envelope.

Monocyte diapedesis through an in vitro vessel wall construct: inhibition with monoclonal antibodies to thrombospondin

Human peripheral blood monocytes were examined for migration across an endothelial cell monolayer in an in vitro vessel wall construct. Few monocytes invaded in the absence of a chemotactic gradient, despite significant adhesion to the endothelial monolayer. However, the addition of zymosan-activated human plasma to the lower compartment, to create a chemotactic gradient across the vessel wall, resulted in significantly enhanced monocyte migration. Pretreatment of the monocytes with monoclonal antibodies to thrombospondin (TSP) dramatically inhibited monocyte diapedesis into the vessel wall. The same treatment inhibited monocyte adhesion to endothelial cells in two-dimensional monolayer cultures as well as in vessel wall constructs (no chemotactic gradient). Of interest, however, the monoclonal antibodies had no inhibitory effect on monocyte migration into collagen gels devoid of endothelial cells in response to the same chemotactic gradient, suggesting the importance of TSP in monocyte-endothelial cell interactions. Monoclonal antibodies to fibronectin and normal mouse immunoglobulin G did not inhibit migration in this model of a vessel wall. Furthermore, monoclonal antibodies to TSP showed no inhibition of human peripheral blood neutrophil migration. Previous studies have shown that monocytes synthesize TSP and express this moiety on their surface. The present data suggest that monocytes may utilize TSP to interact with endothelial cells lining the vessel wall during diapedesis.

The recording and analysis of EMG and jaw tracking. I. The recording procedure

A computer-based system is described which records and analyses electromyographic (EMG) signals and tracking data for mandibular movements during function. EMG signals were obtained bilaterally from six muscles and a Sirognathograph monitored the position of the lower incisor teeth in three dimensions. Directed jaw movement tasks by subjects were monitored. These data were continuously sampled at a rate of 1 KHz per channel over an operator controlled period. Analysis of the data was performed off-line following the experiment. Individual chewing cycles associated with masticatory function were identified and the timing and dimensions of each chewing envelope established. Corresponding EMG values were also determined and displays of EMG and jaw movement were plotted on a common time base. An average chewing cycle and correlated EMG activity could also be displayed on a high resolution monitor and plotted for a hard copy to enable a comparison to be made between subjects with and without jaw dysfunction.

Muscle sarcomere lesions and thrombosis after spaceflight and suspension unloading

Spaceflight (flight) and tail suspension-hindlimb unloading (unloaded) produced significant decreases in fiber cross-sectional areas of the adductor longus (AL), a slow-twitch antigravity muscle. However, the mean wet weight of the flight AL muscles was near normal, whereas that of the suspension unloaded AL muscles was significantly reduced. Interstitial edema within the flight AL, but not in the unloaded AL, appeared to account for this apparent disagreement. In both experimental conditions, the slow-twitch oxidative fibers atrophied more than the fast-twitch oxidative-glycolytic and fast-twitch glycolytic fibers. Immunostaining showed that slow-twitch oxidative fibers expressed fast myosin, producing hybrid fibers containing slow and fast myosin isoforms. Two-dimensional gel electrophoresis of flight AL muscles revealed increased content of fast myosin light chains and decreased amounts of slow myosin light chains and fatty acid-binding protein. In the flight AL, absolute mitochondrial content decreased, but the relatively greater breakdown of myofibrillar proteins maintained mitochondrial concentration near normal in the central intermyofibrillar regions of fibers. Subsarcolemmal mitochondria were preferentially lost and reduced below normal concentration. Elevated fiber immunostaining for ubiquitin conjugates was suggestive of ubiquitin-mediated breakdown of myofibrillar proteins. On return to weight bearing for 8-11 h, the weakened atrophic muscles exhibited eccentric contraction-like lesions (hyperextension of sarcomeres with A-band filaments pulled apart and fragmented), tearing of the supporting connective tissue, and thrombosis of the microcirculation. Segmental necrosis of muscle fibers, denervation of neuromuscular junctions, and extravasation of red blood cells were minimal. Lymphocyte antibody markers did not indicate a significant immune reaction. The flight AL exhibited threefold more eccentric-like lesions than the unloaded AL; the high reentry G forces experienced by the flight animals, but not the unloaded group, possibly accounted for this difference. Muscle atrophy appears to increase the susceptibility to form eccentric contraction-like lesions after reloading; this may reflect weakening of the myofibrils and extracellular matrix. Microcirculation was also compromised by spaceflight, such that there was increased formation of thrombi in the post-capillary venules and capillaries. This blockage led to edema by 8-11 h after resumption of weight bearing by the COSMOS 2044 rats. The present findings indicate that defective microcirculation most likely accounted for the extensive tissue necrosis and microhemorrhages observed for COSMOS 1887 rats killed 2 days after landing.

Coronary bypass surgery improves global and regional left ventricular function following thrombolytic therapy for acute myocardial infarction. TAMI Study Group

Coronary bypass surgery was performed prior to hospital discharge in 303 (22%) of 1387 consecutive patients enrolled in the TAMI 1 to 3 and 5 trials of intravenous thrombolytic therapy for acute myocardial infarction. Bypass surgery was of emergency nature (less than 24 hours from treatment with intravenous thrombolytic therapy) in 36 (2.6%) and was deferred (greater than 24 hours) in 267 (19.3%) patients. The indications for bypass surgery included failed angioplasty (12%); left main or equivalent coronary disease (9%); complex or multivessel coronary disease (62%); recurrent postinfarction angina (13%); and refractory pump dysfunction, mitral regurgitation, ventricular septal rupture or abnormal predischarge functional test (1% each). Although patients having bypass surgery were older (59.5 +/- 9.8 versus 56.0 +/- 10.2 years, (p less than 0.0001), had more extensive coronary artery disease (46% with three-vessel disease versus 11%, (p less than 0.0001), had more frequent diabetes mellitus (19% versus 15%, (p = 0.048), had more prior infarctions (p less than 0.0001), had more severe initial depression in global left ventricular ejection fraction (48.0 +/- 11.9% versus 51.8 +/- 11.9%, p = 0.0002), and regional infarct zone (-2.7 +/- 0.94 versus -2.5 +/- 1.1 SD/chord, p = 0.02) and noninfarct zone function (-0.36 +/- 1.8 versus 0.43 +/- 1.6 SD/chord, p less than 0.0001) than patients not having coronary bypass surgery, no difference in the incidence of death in hospital (7% surgical versus 6% nonsurgical) or death at long-term follow-up of hospital survivors (7% surgical versus 6% nonsurgical) was noted between groups. Surgical patients demonstrated a greater degree of recovery in left ventricular ejection fraction (3.4 +/- 9.8% versus 0.16 +/- 8.5%, p = 0.036) and infarct zone regional function (0.71 +/- 1.1 versus 0.34 +/- 0.99 SD/chord, p = 0.001) when immediate (90 minutes following initiation of thrombolytic therapy) and predischarge (7 to 14 days after treatment) contrast left ventriculograms were compared than did patients who received only intravenous thrombolytic therapy with or without coronary angioplasty. These data suggest a beneficial influence of coronary bypass surgery on left ventricular function and possibly on the clinical outcome of patients initially treated with intravenous thrombolytic therapy for acute myocardial infarction.

Clinical experience with the Palmaz-Schatz coronary stent

Complications that occurred in 247 patients who underwent successful elective stenting to native coronary arteries with the Palmaz-Schatz balloon expandable stent included subacute thrombosis in 7 patients (2.8%), myocardial infarction in 3 (1.2%), death 3 (1.2%), urgent bypass surgery in 4 (1.6%) and major bleeding events in 24 (9.7%). Angiographic restenosis occurred in 21 (20%) of 103 patients who received a single stent. Subgroup analysis, however, revealed that restenosis of a single stent occurred in 3 (7%) of 45 patients without prior angioplasty compared with 25 (27%) of 91 patients with prior angioplasty. Patients with "suboptimal" angioplasty results (dis-section) who received a single stent seemed to have a higher thrombosis rate perioperatively (4 [4%] of 98), but no higher incidence of restenosis (7 [15%] of 46) than that of the total group of patients who received a single stent. Coronary stenting may be a valuable adjunct to coronary angioplasty in carefully selected patients. Complication rates are similar to those of routine angioplasty; however, angiographic restenosis may be reduced in certain subsets of patients.

Myocardial infarction with minimal coronary atherosclerosis in the era of thrombolytic reperfusion. The Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) Study Group

The incidence of minimal residual atherosclerotic coronary obstruction after successful intravenous thrombolytic therapy was evaluated in 799 patients with acute myocardial infarction. Minimal residual coronary obstruction (less than or equal to 50%) was observed on selective coronary angiography performed 90 min after initiation of thrombolytic therapy in 43 patients (5.5%). In 42 other patients (5.4%), a greater than 50% but less than 100% residual stenosis noted at 90 min demonstrated further resolution of obstruction to less than 50% at an angiographic follow-up study 7 to 10 days later. Patients with minimal residual coronary obstruction were significantly younger (52 +/- 10.7 versus 56.7 +/- 10 years; p = 0.002) and had less multivessel coronary disease (p less than 0.001), better initial left ventricular ejection fraction (54 +/- 12% versus 50.2 +/- 11.4%; p = 0.006) and a lower in-hospital mortality rate (1% versus 7%; p = 0.04) than did patients who had a significant (greater than 50%) residual coronary obstruction after intravenous thrombolysis. Long-term follow-up study of patients with a minimal coronary lesion (average 1.5 +/- 0.6 years) and those with significant residual stenosis (average 1.6 +/- 0.7 years) demonstrated that the incidence of death (2.4% in patients with minimal stenosis versus 3.5% in those with significant stenosis) and recurrent myocardial infarction (5% each) were similar in both groups. New strategies are needed to prevent coronary rethrombosis in patients with minimal atherosclerosis after thrombolytic therapy for acute myocardial infarction.

Compensatory mechanisms in platelet production: the response of Sl/Sld mice to 5-fluorouracil

Sl/Sld mice are a unique animal model for studying platelet production in that they sustain normal platelet mass despite reduced marrow activity. The aim of this study was to determine if the compensatory mechanisms operating in these mice could be augmented by further reducing bone marrow activity with the drug 5-fluorouracil (5-FU), known to induce a strong stimulatory effect on platelet production. The platelet recovery in Sl/Sld mice after 5-FU administration contrasted that found in their normal littermates. Sl/Sld mice did not display the sustained thrombocytosis that was observed in +/+ mice between days 10 and 14. Platelet number was elevated in Sl/Sld mice at day 20, when the marrow megakaryocyte compartment had normalized. A significant increase in marrow megakaryocyte number and size was observed at days 8 and 11 in both +/+ and Sl/Sld mice after 5-FU administration. The data suggest that the increase in megakaryocyte size and number following 5-FU treatment was not able to significantly contribute to a sustained rebound thrombocytosis at the time of increased marrow megakaryocytopoiesis. It is concluded that the already compromised marrow of Sl/Sld mice is able to respond to the damage invoked by 5-FU to produce larger than normal megakaryocytes. In contrast to normal mice (+/+ littermates), the increase in marrow megakaryocytopoiesis observed does not lead to a thrombocytosis, indicating that platelet production and release in Sl/Sld mice cannot be further amplified by a strong marrow stimulation.

Consequences of reocclusion after successful reperfusion therapy in acute myocardial infarction. TAMI Study Group

To determine the clinical consequences of reocclusion of an infarct-related artery after reperfusion therapy, we evaluated 810 patients with acute myocardial infarction. Patients were admitted into four sequential studies with similar entry criteria in which patency of the infarct-related artery was assessed by coronary arteriography 90 minutes after onset of thrombolytic therapy. Successful reperfusion was established acutely in 733 patients. Thrombolytic therapy included tissue-type plasminogen activator (t-PA) in 517, urokinase in 87, and a combination of t-PA and urokinase in 129 patients. All patients received aspirin, intravenous heparin and nitroglycerin, and diltiazem during the recovery phase. A repeat coronary arteriogram was performed in 88% of patients at a median of 7 days after the onset of symptoms. Reocclusion of the infarct-related artery occurred in 91 patients (12.4%), and 58% of these were symptomatic. Angiographic characteristics at 90 minutes after thrombolytic therapy that were associated with reocclusion compared with sustained coronary artery patency were right coronary infarct-related artery (65% versus 44%, respectively) and Thrombolysis in Myocardial Infarction (TIMI) flow 0 or 1 (21% versus 10%, respectively) before further intervention. Median (interquartile value) degree of stenosis in the infarct-related artery at 90 minutes was similar between groups: 99% for reoccluded (value, 90/100%) compared with 95% for patent (value, 80/99%). Patients with reocclusion had similar left ventricular ejection fractions compared with patients with sustained patency at follow-up. However, patients with reocclusion at follow-up had worse infarct-zone function at -2.7 (value, -3.2/-1.8) versus -2.4 (SD/chord) (value, -3.1/-1.3) (p = 0.016). The recovery of both global and infarct-zone function was impaired by reocclusion of the infarct-related artery compared with maintained patency; median delta ejection fraction was -2 compared with 1 (p = 0.006) and median delta infarct-zone wall motion was -0.10 compared with 0.34 SD/chord (p = 0.011), respectively. In addition, patients with reocclusion had more complicated hospital courses and higher in-hospital mortality rates (11.0% versus 4.5%, respectively; p = 0.01). We conclude that reocclusion of the infarct-related artery after successful reperfusion is associated with substantial morbidity and mortality rates. Reocclusion is also detrimental to the functional recovery of both global and infarct-zone regional left ventricular function. Thus, new strategies in the postinfarction period need to be developed to prevent reocclusion of the infarct-related artery.

Maxillofacial surgery and the troubles of Northern Ireland

In Northern Ireland, for the last 20 years, an evil and unnecessary conflict has presented the maxillofacial surgeons with a spectrum of violent injuries to the face and neck. The result has been a valuable surgical school and it was the object of my elective to study the progression of the methods used in the management of these injuries and the lessons learnt from them.

Skeletal muscle fiber, nerve, and blood vessel breakdown in space-flown rats

Histochemical and ultrastructural analyses were performed postflight on hind limb skeletal muscles of rats orbited for 12.5 days aboard the unmanned Cosmos 1887 biosatellite and returned to Earth 2 days before sacrifice. The antigravity adductor longus (AL), soleus, and plantaris muscles atrophied more than the non-weight-bearing extensor digitorum longus, and slow muscle fibers were more atrophic than fast fibers. Muscle fiber segmental necrosis occurred selectively in the AL and soleus muscles; primarily, macrophages and neutrophils infiltrated and phagocytosed cellular debris. Granule-rich mast cells were diminished in flight AL muscles compared with controls, indicating the mast cell secretion contributed to interstitial tissue edema. Increased ubiquitination of disrupted myofibrils implicated ubiquitin in myofilament degradation. Mitochondrial content and succinic dehydrogenase activity were normal, except for subsarcolemmal decreases. Myofibrillar ATPase activity of flight AL muscle fibers shifted toward the fast type. Absence of capillaries and extravasation of red blood cells indicated failed microcirculation. Muscle fiber regeneration from activated satellite cells was detected. About 17% of the flight AL end plates exhibited total or partial denervation. Thus, skeletal muscle weakness associated with spaceflight can result from muscle fiber atrophy and segmental necrosis, partial motor denervation, and disruption of the microcirculation.

Morphology of left anterior descending coronary territory lesions as a predictor of anterior myocardial infarction: a CASS Registry Study

Despite a growing awareness of the correlation of coronary artery stenoses morphology with clinical syndromes, no comprehensive, prospective analysis of the implications of stenosis morphology on risk of myocardial infarction has been reported. Angiograms from 118 patients, representative of the 4.9% of medically treated Coronary Artery Surgery Study (CASS) patients who during subsequent 3 year follow-up study had an anterior myocardial infarction, were matched on the basis of arteriographic anatomy and disease with 141 patients who did not have an anterior infarction. Angiograms from these 259 patients with 557 left anterior descending artery stenoses were reviewed without knowledge of clinical outcome. Conditional regression analyses were performed to determine the importance of stenosis morphology, relative to computer-determined stenosis severity and other clinical variables, in the prediction of risk of infarction. Univariate analysis revealed luminal roughness (odds ratio 4.5; p = 0.001) and lesion length (odds ratio 1.7 per unit length; p = 0.007) to be highly correlated with future risk of infarction. Multivariate analysis revealed left anterior descending artery percent stenosis greater than or equal to 50%, lesion roughness, left circumflex artery stenosis and smoking, in that order, to be predictive of anterior myocardial infarction, whereas 22 other morphologic variables were not independently predictive of outcome. The importance of stenosis roughness may relate to its propensity for thrombogenesis and should be considered in clinical decision making.

An investigation of factors affecting progress of patients on a stroke unit

The aim of the study was to identify factors affecting the progress in physical abilities and activities of daily living of patients admitted to a stroke unit. A series of 70 patients admitted consecutively were assessed on a series of tests of motor, functional and cognitive abilities at admission. They were assessed for level of motor abilities and activities of daily living at discharge and 9 months after stroke. Predictive equations were developed which account for between 61% and 33% of the variance in motor abilities and activities of daily living at discharge and at 9 months after stroke. The most important factor influencing outcome was the degree of motor loss.

Prenatal development and innervation of the circumvallate papilla in the mouse

The embryonic development of the circumvallate papilla in the mouse is described. Serial sections of Day 11 to Day 18 mouse embryos were stained by Linder's silver method and examined to determine the temporal events in relation to circumvallate papilla formation. This was complemented by scanning electron micrographs. On Day 13, the earliest sign of a single median circumvallate papilla formation was visible as an epithelial invagination which had bilateral nerve innervation. Scanning electron micrographs of this stage showed a median flattened area demarcated at its periphery by cells invaginating from the surface. On Day 14, the epithelial invagination appeared like an inverted cup with a dense nerve plexus within its core. By the afternoon of Day 14 a furrow had formed by a split in the epithelium. During that period the surface morphology changed from a flattened area to a central dome-shaped structure. As development progressed the furrow became accentuated by the elevation of its lateral walls. Nerve fibres penetrated the epithelium, but taste bud differentiation was not easily observable. The dense innervation of the circumvallate papilla was established from the start of its formation. The role of these nerves as an inductive factor or as providing a trophic effect on the formation of the circumvallate papilla remains to be investigated.

Catalase-positive microperoxisomes in rat soleus and extensor digitorum longus muscle fiber types

The size, distribution, and content of catalase-reactive microperoxisomes were studied cytochemically in slow-twitch oxidative (SO), fast-twitch oxidative glycolytic (FOG), and fast-twitch glycolytic (FG) fibers of soleus and extensor digitorum longus (EDL) rat muscles. Fiber types were classified on the basis of mitochondrial content and distribution, Z-band widths, and myofibril size and shape. Microperoxisomes were generally located between myofibrils at the I-bands. The absence of crystalloid inclusions prevented positive identification of microperoxisomes in nonreacted and aminotriazole-inhibited muscles. EDL and soleus SO fibers possessed the largest microperoxisomes, whereas FOG and FG fibers of the EDL contained small- to medium-sized microperoxisomes. Comparing either microperoxisome number per muscle fiber area or microperoxisome area per fiber area revealed significant differences between fiber types with this ranking: soleus SO greater than EDL SO greater than EDL FOG greater than EDL FG. The present observations demonstrate that the content of catalase-positive microperoxisomes is greatest in the oxidative muscle fiber types. These cytochemical findings account for the higher catalase activity in homogenates of soleus muscles as compared to that of EDL muscles, because the soleus contains more oxidative fibers than EDL.

Quantitation and immunocytochemical localization of ubiquitin conjugates within rat red and white skeletal muscles

We employed solid-phase immunochemical methods to probe the dynamics of ubiquitin pools within selected rat skeletal muscles. The total ubiquitin content of red muscles was greater than that of white muscles, even though the fractional conjugation was similar for both types of muscle. The specificity for conjugated ubiquitin in solid-phase applications, previously demonstrated for an affinity-purified antibody against SDS-denatured ubiquitin, was retained when used as a probe for ubiquitin-protein adducts in tissue sections. Immunohistochemical localization revealed that differences in ubiquitin pools derived from the relative content of red (oxidative) vs white (glycolytic) fibers, with the former exhibiting a higher content of ubiquitin conjugates. Subsequent immunogold labeling demonstrated statistically significant enhanced localization of ubiquitin conjugates to the Z-lines in both red and white muscle fiber types.

Prediction of risk of anterior myocardial infarction by lesion severity and measurement method of stenoses in the left anterior descending coronary distribution: a CASS Registry Study

To assess the 3 year risk of anterior myocardial infarction in patients with left anterior descending coronary artery territory disease (30 to 100% stenosis), National Heart, Lung, and Blood Institute (NHLBI) Coronary Artery Surgery Study (CASS) registry patients were identified who were 1) medically treated, and 2) had evidence of viable anterior myocardium at the time of baseline angiography. Prospectively, 118 patients having an anterior infarction within 3 years of baseline angiography were identified from annual follow-up of 4,535 medically treated patients who had left anterior descending coronary artery disease and viable anterior myocardium. From the large residual pool of patients without infarction, 141 were randomly selected from a stratified matrix to represent the entire group. The maximal percent stenosis was estimated by the CASS multiple angiographers, by a current single observer rereading and by contemporary computer measurement techniques. Absolute lumen dimension was assessed by computer measurement. The 3 year risk of anterior infarction was 2% for patients with their most severe left anterior descending stenosis less than 50%, 6% for patients with one such stenosis greater than or equal to 50% and 11% for patients with two or more such stenoses greater than or equal to 50% (p less than 0.02). Stenoses of 90 to 98% had the highest (15%) 3 year risk of anterior myocardial infarction. The three methods used to measure maximal percent stenosis differed little with regard to their predictiveness. Absolute lumen dimension was less predictive of risk. These results may provide a more rational basis on which to base coronary revascularization decisions.

Metabolism of benz[j]aceanthrylene (cholanthrylene) and benz[l]aceanthrylene by induced rat liver S9

The metabolites of benz[j]aceanthrylene (B[j]A) produced by incubation with liver S9 proteins from rats induced with Aroclor-1254 and phenobarbital have been identified as: trans-B[j]A-1,2-dihydrodiol, B[j]A-9,10-dihydrodiol, B[j]A-11,12-dihydrodiol, and 10-hydroxy-B[j]A. The major metabolite formed (58-60%) by both induced S9 preparations was trans-B[j]A-1,2-dihydrodiol, the cyclopenta-ring dihydrodiol while oxidation at the k-region or the proximal-bay region was minor. There were no statistical differences in individual or total B[j]A metabolite rates between the 2 induced S9 preparations. B[l]A was metabolized by Aroclor-1254 and phenobarbital induced rat liver S9 preparations to trans-B[l]A-1,2-dihydrodiol, B[l]A-7,8-dihydrodiol, and B[l]A-4,5-dihydrodiol. The major B[l]A metabolite formed (28-40%) by both induced S9 preparations was B[l]A-7,8-dihydrodiol, the k-region dihydrodiol. Cyclopenta-ring oxidation to trans-B[l]A-1,2-dihydrodiol was approximately 50% of that observed for k-region oxidation. Both induced S9s produced similar rates of B[l]A metabolites except for B[l]A-7,8-dihydrodiol formation which was higher for Aroclor-1254-induced S9.

Species variation in bladder cell and liver cell activation of acetylaminofluorene

The metabolism and mutagenicity of 2-acetylaminofluorene were measured using freshly prepared intact bladder and liver cells from the cow, dog and rat. High pressure liquid chromatography was used to separate 2-acetylaminofluorene metabolites, and Salmonella typhimurium, strain TA98, was used to detect mutagenic intermediates. Species differences as well as animal-to-animal variation within a species were observed. Mutagenic activity with 2-acetylaminofluorene was greater with cow bladder cells than with dog or rat bladder cells. However, dog bladder cells were most active in metabolizing 2-acetylaminofluorene, and rat bladder cells were least active. Liver cells from all three species metabolized 2-acetylaminofluorene to mutagens for Salmonella, with dog and cow cells being more active than rat liver cells. However, cow liver cells were the most active in metabolizing 2-acetylaminofluorene, followed by rat and dog cells. With all cell types studied, except rat bladder cells, aminofluorene was the major metabolite detected. Carbon and N-hydroxylated products were produced by liver and bladder cells of the three species and glucuronide and sulfate conjugates of the metabolites were detected from both cell types. Correlations between mutagenic activity and the level of metabolism or any individual metabolite were not apparent. The data suggest that the relative contribution of bladder cell metabolism in aromatic amine induced bladder cancer may vary with the species.

Idiotype-anti-idiotype interactions of VHIX-coded anti-progesterone and anti-arsonate antibodies. Comparison of passive haemagglutination and radioimmunoassays

The reactivity and specificity of polyclonal and monoclonal anti-idiotypic antibodies raised against monoclonal anti-progesterone and anti-arsonate antibodies have been studied by solid phase radioimmunoassay (RIA) with immobilized idiotype and by passive haemagglutination with idiotype-coupled red cells. The sensitivity of the two methods was comparable, though some cross-reactions were only detected by RIA. Passive haemagglutination was found to be especially suitable in screening for monoclonal anti-idiotypes in hybridoma supernatants and ascites, and had advantages over RIA in detection of syngeneic anti-idiotypes. Demonstration of binding site-associated idiotopes was possible by haemagglutination inhibition. RIA and haemagglutination were used to investigate the idiotypic relationships between BALB/c antiprogesterone and anti-arsonate monoclonal antibodies which share heavy chains encoded by VHIX variable region genes.