The effect of nutritional supplements on food intake in patients undergoing radiotherapy

PURPOSE/OBJECTIVES

To describe the effect of nutritional supplements on food intake in patients undergoing radiotherapy.

DESIGN

Experimental prospective.

SAMPLE

40 newly diagnosed patients with cancer beginning external beam radiation therapy.

METHODS

Weekly dietary counseling and recording of total daily dietary intake for three days a week for four weeks. One half of the subjects were randomly assigned to ingest a liquid nutritional supplement between meals and at bedtime.

MAIN RESEARCH VARIABLES

Total daily protein and caloric intake, food-derived protein and caloric intake, and supplement-derived protein and caloric intake.

FINDINGS

Subjects ingesting nutritional supplements between meals significantly increased their total caloric and protein intake above that of controls and did not reduce their food-derived caloric or protein intake compared to controls.

CONCLUSIONS

Nutritional supplements can be used to increase total caloric and protein intake without causing a significant reduction in food intake.

IMPLICATIONS FOR NURSING PRACTICE

In this patient sample, supplements were not substituted for food intake. Further research is needed to determine the effects of supplements on appetite in patients with advanced cancer.

Persons and their copies

Is cloning human beings morally wrong? The basis for the one serious objection to cloning is that, because of what a clone is, clones would have much worse lives than non-clones. I sketch a fragment of moral theory to make sense of the objection. I then outline several ways in which it might be claimed that, because of what a clone is, clones would have much worse lives than non-clones. In particular, I look at various ideas connected with autonomy. I conclude that there is no basis to the claim that, because of what a clone is, clones would have much worse lives than non-clones. I therefore reject the claim that cloning human beings is morally wrong.

N-terminal and C-terminal modifications affect folding, release from the ribosomes and stability of in vitro synthesized proteins

Important aspects of translation are release and folding of the synthesized protein into its three-dimensional structure. Studies from our group indicated that during in vitro protein synthesis a large portion of full-length polypeptides apparently accumulated as peptidyl-tRNA on ribosomes. We have also shown that some proteins though released in biologically active form may be inactivated without being degraded. These experiments were carried out by coupled transcription/translation using an Escherichia coli extract in which eukaryotic or prokaryotic test proteins were synthesized from their coding sequence inserted into specific plasmids. Experiments described here were designed to analyze the effects of N-terminal and C-terminal modifications of the coding sequence on the ribosomal release/termination process and on the stability of the newly synthesized protein. Elimination of the leader sequence in two proteins tested, mitichondrial rhodanese and bacterial beta-lactamase, caused an increase in the percentage of polypeptides released from the ribosomes relative to total synthesis. Conversely, an N-terminal extension such as a histidine-lag impaired the ribosomal release process. Also, a hydrophobic N-terminal modification of the synthesized protein reduced release of newly formed protein from the ribosomes. A C-terminal extension of the coding sequence for rhodanese by one amino acid decreased the percentage released polypeptide and furthermore affected the stability of the in vitro formed protein. We propose that a regulatory mechanism exists by which N-terminal and C-terminal sequences of a newly synthesized protein have feed-back effects on the termination factor-mediated release and on the stability of the native three-dimensional structure.

Nonsteroidal anti-inflammatory drug-related gastrointestinal toxicity: definitions and epidemiology

Nonsteroidal anti-inflammatory drug (NSAID)-associated gastrointestinal (GI) toxicity is a broad topic encompassing symptoms as well as severe GI complications. GI bleeding and perforation are the 2 overlapping components that account for the majority of deaths and disability associated with these drugs. Abnormal gastric endoscopic profiles as well as symptoms such as heartburn, pain, and dyspepsia are common in NSAID users, but no correlation has been found between these factors and the occurrence of the more severe complications; therefore, neither symptoms nor endoscopic observations can necessarily be considered reliable predictors of future outcomes. Confounding factors can increase the risk of complications, and specific NSAIDs vary in the magnitude and type of risk attending their use. Recent studies have focused on the contribution of nonprescription NSAIDs to total complications, and combined with evidence suggesting that the risk is greatest during the first month of NSAID use, it is apparent that NSAID toxicity is an acute as well as a chronic problem.

Comparative evaluation of four different infusion rates of ropivacaine (2 mg/mL) for epidural labor analgesia

BACKGROUND AND OBJECTIVES

Previous studies have reported comparable efficacy for ropivacaine and bupivacaine when used for labor analgesia at concentrations of 2.5 mg/mL. In this multicenter study, we assessed ropivacaine at the commercially available concentration of 2 mg/mL (0.2%) for labor pain management.

METHODS

After Institutional Review Board approval and informed consent, 128 women at term were randomly assigned to receive ropivacaine at one of the four infusion rates via a lumbar epidural catheter. Analgesia was initiated with a 5-mL test dose, followed by injections of 5-15 mL of 2 mg/mL ropivacaine. The continuous infusion was then started at 4, 6, 8, or 10 rmL/hour. Rescue analgesia was provided with 5-mL "top-up" injections as necessary to provide maternal comfort. Pain relief was assessed by using a visual analog pain scale (VAPS) and motor block was assessed by using a modified Bromage scale.

RESULTS

All infusion regimens effectively decreased VAPS, and most patients in all groups had minimal or no motor block at the end of the first stage of labor. Mean total number of the top-up injections required per patient were 3, 2, 1.5, and 1.4, respectively, in the 4, 6, 8, and 10-mL/hour groups (P < .05, 4 mL/hour vs. all other groups). Despite receiving more total bolus dosages, the 4-mL/hour group had less motor block in the lower extremities (P < .05). Apgar scores and neurological adaptive capacity scores were similar for all groups.

CONCLUSIONS

The 2 mg/mL of ropivacaine produces satisfactory labor analgesia at epidural infusion rates of 4, 6, 8, and 10 mL/hour, provided supplemental bolus dosages are available. Clinically, a rate of 6 mL/hour may be the lowest effective rate that provides the best combination of pain relief, motor block, and rebolusing, although rates of 8 and 10 mL/hour produced similar results.

Reactivation of thermally inactivated pre-beta-lactamase by DnaK, DnaJ, and GrpE

To understand the role of the 23-amino acid signal sequence in the folding and stability of beta-lactamase, the precursor and a mutant beta-lactamase with a 19-amino acid signal sequence deletion were synthesized in vitro using an Escherichia coli cell-free coupled transcription/translation system. Approximately 30% of the newly synthesized full-length precursor and 60% of the deletion mutant polypeptides were terminated and released from the ribosomes as active enzyme. Activity of the pre-beta-lactamase, but not the mutant, was unstable at 37 degrees C, suggesting that the signal sequence causes the enzyme to unfold. This inactivation was independent of ATP. Pre-beta-lactamase activity was stabilized by lowering the temperature to 30 degrees C. Furthermore, addition of the molecular chaperones DnaK/J and GrpE, in the presence of ATP and Mg2+, restored the activity of the temperature-inactivated precursor. The precursor formed a stable complex with DnaK and GrpE. Both ATP and DnaJ were required for recovery of enzymatic activity, indicating that DnaJ may bind transiently to the complex. These results suggest that the signal sequence of the pre-beta-lactamase causes a temperature-dependent unfolding of the synthesized enzyme and that DnaK/J and GrpE interact with unfolded pre-beta-lactamase to promote refolding of the protein into its native, enzymatically active conformation.

Generation of a nude mouse tumor model for in vivo replication of human cytomegalovirus

Human cytomegalovirus (HCMV) is a common opportunistic infection resulting in retinitis in 15%-40% of AIDS patients. Several anti-HCMV therapies are currently available, and new treatments are in various stages of development. An HCMV animal model involving in vivo infection of human cells without the dependence on human fetuses or multiple surgical procedures has been developed. A human glioblastoma cell line that is permissive for HCMV replication (U373MG) was adapted to grow as a subcutaneous tumor in nude mice. These tumors arise in approximately 7 days and grow progressively. An evaluation of HCMV DNA replication demonstrated an increase in the accumulation of HCMV DNA within infected tumors from 48 to 168 h after infection. Immunohistochemical analysis showed focal areas of HCMV infection in which expression of immediate-early and late antigens was detected. In addition, it was demonstrated that ganciclovir inhibited HCMV DNA replication in vivo in a dose-dependent manner.

Health services research at United HealthCare Corporation: the role of the Center for Health Care Policy and Evaluation

This article describes collaborative health services research and performance evaluation activities at United HealthCare Corporation, a national health care management services company. We outline the development of a research capacity within our company, the principal data sources used, and the types of research conducted. The importance of health services research within a managed care system is illustrated using two projects as examples. finally, we discuss issues faced by organizations such as ours in defining appropriate research priorities, ensuring health plan participation, and disseminating research findings. Lessons learned should be of interest to health services researchers working in or collaborating with managed care organizations as well as others seeking to understand the dynamics of research in private-sector health care companies.

The diagnosis of iron deficiency in patients with rheumatoid arthritis and anemia: an algorithm using simple laboratory measures

OBJECTIVE

Anemia of chronic disorders (ACD) and iron deficiency are common features in rheumatoid arthritis (RA), but may be difficult to distinguish without marrow sampling, which is invasive, time consuming, and expensive. We sought simple laboratory measures that identified patients with absent marrow iron stores (iron deficiency).

METHODS

45 anemic patients with RA underwent marrow sampling in addition to a complete blood count and serum ferritin and iron saturation measurements.

RESULTS

47% of patients had iron deficiency. These patients had significantly lower mean corpuscular volume (MCV), serum ferritin, and iron saturation. A 3 step algorithm was developed using these laboratory variables to identify iron deficiency. This algorithm correctly classified 94% patients with iron deficiency and 85% with ACD.

CONCLUSION

Our study demonstrates that iron deficiency may be reliably identified by measuring serum ferritin, MCV, and iron saturation in many patients with RA, thereby avoiding the trauma and expense of marrow sampling.

Cotranslational folding of nascent proteins on Escherichia coli ribosomes

Evidence is presented for cotranslational folding of rhodanese or ricin during its synthesis on Escherichia coli ribosomes. During transcription-translation, full-length but enzymatically inactive polypeptides accumulated as peptidyl-tRNA on the ribosomes. These polypeptides were activated and released by subsequent incubation with the bacterial chaperones and with release factor (RF-2). Coumarin was incorporated cotranslationally at the N-terminus of the nascent protein from fluorophore-S-Ac-Met-tRNAf. Changes in fluorescence indicated that DnaJ bound to the nascent proteins and to a fluorescently labeled synthetic peptide corresponding to the N-terminal 17 amino acids of bovine rhodanese. This peptide also bound to 70S ribosomes or 50S subunits but not to 30S subunits. It inhibited activation and RF-2-dependent release of the full-length ribosome-bound rhodanese. A deletion mutant of rhodanese lacking the N-terminal 23 amino acids was not accumulated on the ribosome but was synthesized very efficiently. However, the protein that was formed was enzymatically inactive. DnaJ did not bind to this deletion mutant on ribosomes. We conclude that the chaperone-mediated reactions facilitate binding of the N-terminal sequence of nascent proteins to a specific site on 50S ribosomal subunits where it blocks release. The ribosome-bound protein undergoes chaperone-mediated reactions that are required for folding into an enzymatically active conformation.

Insulin-like growth factor-I enhances immune response in dexamethasone-treated or surgically stressed rats maintained with total parenteral nutrition

BACKGROUND

New evidence suggests that insulin-like growth factor-I (IGF-I) is an important regulator of immune response. Our objective was to determine the effects of IGF-I on immune response during total parenteral nutrition (TPN) using two stress models.

METHODS

Male, Sprague-Dawley rats (230 to 250 g) were given TPN with or without coinfusion of recombinant human IGF-I (800 micrograms/d for 6 days) and subjected to either dexamethasone, a synthetic glucocorticoid, or surgical stress, in the form of a midline abdominal incision. In the dexamethasone model, immune response was assessed by total cellularity of the thymus and spleen, in vitro assays of lymphocyte proliferation, and interleukin 6 (IL-6) production, and concentrations of IL-6 and tumor necrosis factor alpha (TNF-alpha) in serum. In the surgical model, flow cytometry was used to identify and quantify splenic populations of T and B lymphocytes and macrophages.

RESULTS

In rats immunosuppressed by dexamethasone, IGF-I infusion increased mitogen-induced proliferation of thymocytes, but did not alter cellularity in the thymus; enhanced proliferation and IL-6 production in peripheral blood mononuclear cells following treatment with concanavalin A or lipopolysaccharide; and reduced the serum concentration of IL-6, but not TNF-alpha. In surgically stressed rats, IGF-I infusion restored the splenic populations of immature and mature B lymphocytes, which were decreased by TPN.

CONCLUSIONS

our data demonstrate that IGF-1 enhances immune response during TPN in rats.

Synthesis and characterization of an aryl-azidoparoxetine. A novel photo-affinity probe for serotonin-transporter

Paroxetine is an effective antidepressant drug and potent serotonin (5-HT) uptake inhibitor. It selectively labels 5-HT transporter on platelets and neurons. We report here the synthesis of an aryl-azido derivative of paroxetine, which is a novel photoactive and irreversible ligand for the [3H]paroxetine binding site on the platelet 5-HT transporter. The compound inhibited [3H]paroxetine binding (IC50, 55 nM) and 5-HT uptake (IC50, 12 nM) at equilibrium conditions and inactivated 10-20% of [3H]paroxetine binding sites upon irradiation at 320 nm. SDS-PAGE of platelet protein extract labelled with the radioactive analogue of the synthesized probe revealed the presence of four radioactive bands of which the 71-kDa one was the most prominent.

Effects of mild hypoxia on perceptual-motor performance: a signal-detection approach

Twelve healthy male subjects were required to make speeded judgements concerning the orientation of visual stimuli while breathing air at reduced partial pressure in a hypobaric chamber at altitudes of 7000 and 12,000 ft. A control condition was also conducted at sea level, and subjects received practice on the task at sea level prior to the commencement of the experiment. Significantly slower response times were obtained at 7000 and 12,000 ft relative to sea level. A signal-detection analysis showed that accuracy of judgement was significantly poorer at 12,000 ft, but oxygen deprivation has no systematic effect on response criterion.

Comparison of the effects of hydrophobicity, amphiphilicity, and alpha-helicity on the activities of antimicrobial peptides

Multiple linear regression was used to quantify the dependence of the antimicrobial activity of 13 peptides upon three calculated or experimentally determined parameters: mean hydrophobicity, mean hydrophobic moment, and alpha-helix content. Mean hydrophobic moment is a measure of the amphiphilicity of peptides in an alpha-helical conformation. Antimicrobial activity was quantified as the reciprocal of the measured minimal inhibitory concentration (MIC) against Escherichia coli. One of the peptides was magainin 2, and the remainder were novel peptides designed for this study. The multiple linear regression results revealed that the amphiphilicity of the peptides was the most important factor governing antimicrobial activity compared to mean hydrophobicity or alpha-helix content. A better regression of the data was obtained using ln(1/MIC+constant) as the dependent variable than with either 1/MIC or ln(1/MIC). These results should be useful in designing peptides with higher antimicrobial activity.

Whole body autoradiography of CCK-8 in rats

Rats were given i.v., intranasal or intraperitoneal doses of CCK-8 (sulfated) labelled with 125I-labeled Bolton and Hunter reagent. Radioactivity was found mainly in the liver, kidney, and the intestinal contents. No radioactivity was detected in the brain. In animals dosed i.v., specific localization occurred in the tissue of the pyloric region of the stomach, and in the pancreas. Label persisted within the pyloric region of the stomach for longer than 30 min, in spite of the reported half-life of CCK-8 in plasma of approximately 1 min. Intranasal and intraperitoneal doses had limited bioavailability. The binding to the sites in the pyloric region of the stomach, which required systemic delivery, may have identified receptors associated with appetite control.

Leaving patches: Effects of travel requirements

Five pigeons were trained in an analogue foraging procedure in which, by completing a travel requirement, they entered a "patch" in which a reinforcer might be available after an unpredictable time. They also had the opportunity, by emitting a defined response, to exit the patch and travel to another patch. Prey availability in a patch was not signaled. Data were collected on the length of time that subjects stayed in patches before exiting (residence times) as a function of various travel requirements: travel for a fixed time in blackout, fixed-interval schedule traveling, fixed-time traveling with an added response required to terminate traveling, and fixed-ratio traveling. For each of these conditions, the required amount of travel (time or responses) was varied over a wide range. As previously reported, residence times increased with increases in fixed-time traveling, as they did with increasing fixed-interval or fixed-ratio traveling. There was no evidence that adding response or work requirements systematically affected residence time except via increased travel time, although 3 of the 5 birds stayed longer in a patch under higher fixed-ratio values. A "threshold-maximization" model described the data well with a single parameter that was consistent across subjects, procedures, and experiments.

A survey of methods of processing and storage of bone marrow and blood stem cells in the EBMT

We conducted a survey to identify current practices in bone marrow processing, preservation and storage by mailing a questionnaire to 155 bone marrow transplant centres listed in the EBMT records. Approximately 57% of centres replied. There were wide variations in methodology which reflected the different types of disease being treated, local conditions and personal preferences. A number of areas where more caution could be exercised were identified: possible reinfusion of excessive quantities of heparin, possible misuse of disposable needles and lack of awareness of the implications of product liability rules relating to cooling rate, storage and viability data.

Sequence of the rec-2 locus of Haemophilus influenzae: homologies to comE-ORF3 of Bacillus subtilis and msbA of Escherichia coli

The nucleotide sequence of a 4243-bp PstI fragment containing the rec-2 gene of Haemophilus influenzae was determined. The amino acid (aa) sequences of four putative proteins were deduced from the corresponding open reading frames (ORFs). The 2400-bp ORF2 accounted for rec-2, based on the sequences of DNA fragments that contained rec-2::mini-Tn10 mutations. The rec-2 gene encoded a putative 800-aa protein with a M(r) of 90,561. Sequence analysis suggested that the rec-2 product contained nine highly probable integral membrane-spanning segments. Database searches showed that rec-2 was homologous to the comE-ORF3 gene of Bacillus subtilis. This hypothesis is consistent with the known involvement of both of these genes in the passage of transforming DNA through the competent-cell envelope. Although the sequences of the other three ORFs were incomplete, sufficient data were available to allow inferences about their homologies to other genes. ORF4, which overlapped ORF1, was homologous to the Escherichia coli dnaK suppressor gene, dksA, and therefore was named dsh-1 (dnaK suppressor homolog). Mutations in dsh-1 and its putative promoter region caused a mild sensitivity to UV light, but did not affect DNA recombination. ORF3, located downstream from rec-2, was homologous to msbA, an essential gene of E. coli with extensive similarity to the ATP-dependent translocators. ORF3 was named msh-1 (msbA homolog). Mutations in msh-1 had no effects on genetic transformation. The close juxtaposition of rec-2 and msh-1 implied that the expression of msh-1 could be linked to the translation of the rec-2 ORF.

Leaving patches: An investigation of a laboratory analogue

Five pigeons were trained on a procedure that has been used as a laboratory analogue to natural patch residence. Trials commenced with two responses available. One of these might provide a reinforcer if the patch was a prey patch; the other ended the residence time in the patch and, after a fixed travel time in blackout, produced another patch that might or might not provide a reinforcer. Patch residence also ended, and was followed by the same travel time, after a reinforcer was obtained or after a fixed maximum time was spent in the patch. The dependent variable was patch residence time, from the commencement of the patch to the time at which the subject emitted a response to exit from the patch or until the maximum patch residence time had elapsed. In Parts 1 to 3, the duration of the imposed travel time was varied from 0.25 to 16 s at three different probabilities (.05, .1, and .2) of food per second (lambda) in prey patches. As reported in previous research, both increasing travel time and decreasing probabilities of reinforcers per second increased patch residence time. In Parts 4 to 7, the probability of prey trials (rho) was varied in an irregular order from .1, through .2, .5, and .7, to .9 for different combinations of lambda and travel time. Respectively, these were in Part 4, .05 per second and 0.25 s; in Part 5, .05 per second and 16 s; in Part 6, .2 per second and 0.25 s; and in Part 7, .2 per second and 16 s. A previously offered model, based on optimization assumptions, substantially and consistently underpredicted patch residence time. However, a modification of that model, which assumes that the subjects could not accurately discriminate the residence time that provided the minimum interreinforcer interval, described the data well. The same model also described previously reported residence times in a different species with a uniform distribution of prey-arrival times.

An activity gel assay for the detection of DNA helicases and nucleases from cell-free extracts

An activity gel assay was developed for the detection of DNA helicases in crude extracts. The assay was based on the ability of DNA helicases to unwind radioactive fragments from single-stranded M13 circles that were immobilized in an SDS polyacrylamide gel. The displaced radioactive strands were detected by blotting them to a filter and visualizing the resulting bands by autoradiography. Experiments with purified proteins demonstrated that DNA helicases, endonucleases and exonucleases could produce activity bands. A one-dimensional gel assay was sufficiently sensitive to allow detection of DNA helicase I, DNA helicase II, DNA helicase IV, the RecQ helicase as well as 3 unidentified putative DNA helicases in crude extracts of Escherichia coli. Exonuclease and endonuclease activities from crude extracts could be distinguished from DNA helicase activities by their ATP-independence and from each other by their band morphologies.

The effect of pre-fitting counselling on the outcome of hearing aid fittings

The effect of pre-fitting counselling on the outcome of fittings of NHS behind-the-ear hearing aids to adult first-time users was investigated. Questionnaires and diaries were sent both before and after fitting to 48 subjects who were given pre-fitting counselling and 47 control subjects, all of whom were fitted with standard NHS hearing aids in Southampton or Bath between September 1989 and July 1991. The test and control groups had similar distributions of age, sex and hearing loss. Analysis of the data showed that the counselling had no significant effect on levels of satisfaction, aid usage or benefit; these outcome measures also showed no significant correlation with any of the personal characteristics or attitude factors which were studied.

Quantitating cataract and nuclear brunescence, the Harvard and LOCS systems

Subjective and objective systems are used to quantify cataract at The Center for Clinical Cataract Research. We have described each system and its use, presented data on reproducibility and validity, and for objective systems, demonstrated the correlation to the subjective grade of the cataract as defined by the Lens Opacities Classification Systems, Versions II and III (LOCS II and III). The subjective systems are used to classify nuclear color, nuclear opalescence, cortical cataract, and posterior subcapsular cataract. Reported kappa scores for LOCS II range from 0.85 to 1.0. Intraclass correlation coefficients for LOCS III (r1) range from 0.67 to 0.94. The computerized objective system are: (1) fast spectral scanning colorimetry (FSSC) for assessment of nuclear color (r1 = 0.96 to 0.98); (2) nuclear mean density (NMD) for assessment of nuclear opalescence (r1 = 0.97); and (3) percent area opacity (anterior = a; posterior = p) (OPAC-a and OPAC-p) for assessment of cortical and posterior subcapsular cataract (r1 = 0.92 to 0.96).

Association of mononuclear cells and eosinophils with airway resistance and responsiveness in rat pulmonary inflammatory responses

To evaluate the association of various leukocytes with pulmonary resistance and methacholine responsiveness, we induced pulmonary eosinophil-rich inflammation in IgE-sensitized (ovalbumin) Sprague Dawley rats. Sensitized rats were challenged with either relevant (OA) or irrelevant antigen by tracheal insufflation a) with no other treatment, b) in conjunction with intravenous Sephadex beads pretreatment, or c) with antigen coupled covalently to Sepharose beads. About 24 h after antigen challenge, respiratory system resistance (Rrs), response to aerosolized methacholine, and pulmonary histopathology were evaluated. Challenge with OA, insufflation with Sepharose, and treatment with i.v. Sephadex all independently increased inflammatory cell infiltrates, but the combination of OA with the other agents did not significantly enhance the inflammatory response over OA alone. Interactive stepwise regression techniques were utilized to identify correlates for Rrs and methacholine responsiveness. Mononuclear cell score was a significant predictor (p < .01) for Rrs, and insufflation of Sepharose had a significant independent effect on Rrs (p = .01) above that predicted by mononuclear cell infiltrates. Conversely, eosinophil score and neutrophil score were not significant predictors for Rrs, and challenges with antigen or Sephadex had no significant independent effect on Rrs beyond that predicted from mononuclear cell infiltrates. Eosinophil score was the only significant histological predictor for methacholine responsiveness (p < .0001). Challenges with Sephadex, antigen and Sepharose did not significantly change methacholine responsiveness independently of the changes associated with eosinophil infiltrates. These findings suggest that mononuclear cells and eosinophils contribute to increases in airway resistance and responsiveness, respectively, following the induction of pulmonary inflammation by both allergic and non-allergic stimuli.

Leukocyte activation and function-associated antigens in inflammatory disease

Expression of adhesion molecules, CD11a, CD11b and CD18, and of the function-associated molecules CD3, CD4, CD8, CD16, CD19, CD56 and CD57 was assayed on peripheral blood leukocytes from normal control subjects (n = 10), and from patients with adult periodontitis PD (n = 9), ankylosing spondylitis AS (n = 11) and rheumatoid arthritis RA (n = 14). A novel rapid fixation leukocyte preparation technique was used which prevents artefactual up-regulation of surface antigens. In RA patients, the percentage of CD18+ lymphocytes was decreased and that of CD11b+ neutrophils was increased. On lymphocytes the mean fluorescence intensity (MFI) of both CD11b and CD18 was decreased whereas that of CD57 was increased. In AS patients the percentages of CD11b+ lymphocytes and neutrophils were increased and CD18+ lymphocytes and neutrophils were decreased. On lymphocytes the MFIs of CD11b and CD18 were decreased, whilst that of CD16 was increased. On neutrophils the MFI for CD18 was increased. No significant differences (p < 0.01) were seen for the periodontitis patients. It is suggested that the antigen expression on peripheral blood cells from RA and AS patients is consistent with leukocyte activation.

Abnormal binding properties of blood monocytes in rheumatoid arthritis

Blood monocytes from patients with RA exhibited a greater binding to monolayers of umbilical cord vein endothelium than monocytes from control subjects (mean 42% increase; p < 0.01). When control monocytes were added to TNF or IL-1 treated endothelium their adhesion was enhanced (mean 24% increase; p < 0.05), whereas the number of monocytes from RA patients binding to TNF or IL-1 treated monolayers was less than that adhering to untreated endothelial cells (mean 22% inhibition; p < 0.02). The surface expression of CD11b/CD18 on RA monocytes was increased and pretreatment of normal and RA cells with an anti-CD18 monoclonal antibody inhibited their attachment to untreated and cytokine-treated endothelial cells. Normal blood monocytes activated with LPS demonstrated an enhanced binding to untreated cultures (mean 23% increase; p < 0.05) and an inhibited attachment to cytokine-treated endothelial cells. This study suggests that blood monocytes in RA may be activated and that this property modifies the attachment of these cells to normal and "inflammatory" endothelium.

The Lens Opacities Classification System III. The Longitudinal Study of Cataract Study Group

OBJECTIVE

To develop the Lens Opacities Classification System III (LOCS III) to overcome the limitations inherent in lens classification using LOCS II. These limitations include unequal intervals between standards, only one standard for color grading, use of integer grading, and wide 95% tolerance limits.

DESIGN AND RESULTS

The LOCS III contains an expanded set of standards that were selected from the Longitudinal Study of Cataract slide library at the Center for Clinical Cataract Research, Boston, Mass. It consists of six slit-lamp images for grading nuclear color (NC) and nuclear opalescence (NO), five retroillumination images for grading cortical cataract (C), and five retroillumination images for grading posterior subcapsular (P) cataract. Cataract severity is graded on a decimal scale, and the standards have regularly spaced intervals on a decimal scale. The 95% tolerance limits are reduced from 2.0 for each class with LOCS II to 0.7 for nuclear opalescence, 0.7 for nuclear color, 0.5 for cortical cataract, and 1.0 for posterior subcapsular cataract with the LOCS III, with excellent interobserver agreement.

CONCLUSION

The LOCS III is an improved LOCS system for grading slit-lamp and retroillumination images of age-related cataract.

Developing Analytic Thinking Skills in Early Undergraduate Education

This article describes how a required prenursing health issues course was substantially restructured to increase the opportunities for students to develop analytic skills and for faculty to gain greater insight into how the students processed course content. Using writing-to-learn (WTL) strategies based on theories of adult cognitive development (Kinneavy, McCleary, & Nakadate, 1985; Kohlberg, 1978; Perry 1978), course readings, writing assignments, and exam questions were revised continuously over five semesters. This article describes the purpose and process of redesigning the course and some reflections on the outcome.

Apoptosis as a mechanism of tributyltin cytotoxicity to thymocytes: relationship of apoptotic markers to biochemical and cellular effects

Recent in vitro studies have suggested that activation of apoptosis could account for the profound depletion of cortical thymocytes, which characterizes tributyltin (TBT) immunotoxicity. However, it has also been shown that TBT disrupts macromolecular synthesis and cellular energetics to an extent that might be expected to interfere with the initiation of apoptosis. The purpose of these studies was to further evaluate the morphological and biochemical characteristics of thymocyte killing by TBT and to relate this to key cellular processes. Ex vivo thymocyte cultures from immature rats were treated with bis(tri-n-butyltin) oxide (TBTO) at concentrations ranging from those which rapidly produced necrosis (5-10 microM), down to cytotoxic but subnecrotic concentrations (0.1-2 microM). In cells exposed to TBTO concentrations that caused a rapid and near maximal inhibition of protein synthesis, it remained possible to demonstrate the stereotypic internucleosomal DNA cleavage and morphological changes indicative of apoptosis. Further confirmation that apoptosis was occurring independently from protein synthesis was provided by the absence of a protective effect following cycloheximide pretreatment. Apoptosis still occurred in TBTO-treated thymocytes although intracellular ATP levels were depressed to 20% or less of control values. Cytoprotective effects were noted with the intracellular Ca2+ chelators BAPTA-AM and Quin-2 AM, and also with zinc. Cell killing by TBTO occurred without overt disturbance of thymocyte cell cycle parameters. These results indicate that thymocyte apoptosis stimulated by TBT exposure occurs independently of a requirement for protein synthesis and does not require fully conserved cellular energetics.

Picosecond neodymium:yttrium lithium fluoride laser sclerectomy

The picosecond neodymium:yttrium lithium fluoride laser, a high-power, short-pulse laser that uses low energy per pulse and has a high repetition rate and a highly coherent energy source of 1,053 nm, was used to perform sclerectomies by an ab externo approach in human cadaver eyes. We evaluated laser settings with regard to full-thickness scleral perforation and thermal damage to surrounding tissue. We studied energy per pulse, depth per burst (a present number of spots), spot and line separation of the pattern (spacing between spots of the laser in length [spot separation] and width [line separation]), and total energy required to perforate the sclera. Efficiency was determined by evaluating which settings required the fewest spots and least total energy to perforate the sclera. We studied histologic sections of the sclerectomy sites to determine thermal damage to the surrounding sclera. The picosecond neodymium:yttrium lithium fluoride laser is effective in performing full-thickness sclerectomy with minimal thermal damage to the surrounding tissue. The anterior chamber could be penetrated with an average total energy of 13.3 +/- 0.4 (SEM) J. The sclerectomy size was 545 +/- 11 microns externally and 163 +/- 4 microns internally. Successful sclerectomies were performed with as little as 3 to 5 microns of thermal damage to the surrounding scleral tissue with 250 microJ per pulse.

Loss of contrast sensitivity in diabetic patients with LOCS II classified cataracts

Contrast sensitivity function (CSF) was assessed in a population of diabetics with moderate cataracts to determine if CSF testing provides more information about visual dysfunction than Snellen or Lotmar interferometric visual acuity. With the Lens Opacities Classification Systems Version II (LOCS II) of cataract classification it was possible to grade accurately the type and severity of cataract and nuclear brunescence. The presence of statistically significant relationships between increasing LOCS II classification (worsening cataract) and diminished function, even when the regression model was controlled for Snellen visual acuity, supports the thesis that CSF measurements do provide more information about cataract related visual loss than Snellen acuity alone. Statistically significant (p < or = 0.05) relationships existed between different morphological types of cataract, nuclear colour, and CSF at specific frequencies. The frequencies affected differed with cataract type or nuclear colour, and with distance and near CSF.

Adaptive optics for array telescopes using piston-and-tilt wave-front sensing

A near-infrared adaptive optics system operating at approximately 50 Hz has been used to control phase errors adaptively between two mirrors of the Multiple Mirror Telescope by stabilizing the position of the interference fringe in the combined unresolved far-field image. The resultant integrated images have angular resolutions of better than 0.1 arcsec and fringe contrasts of >0.6. Measurements of wave-front tilt have confirmed the wavelength independence of image motion. These results show that interferometric sensing of phase errors, when combined with a system for sensing the wave-front tilt of the individual telescopes, will provide a means of achieving a stable diffraction-limited focus with segmented telescopes or arrays of telescopes.

rec-2-dependent phage recombination in Haemophilus influenzae

The genetic transformation mutant Rd(DB117)rec- has a pleiotropic phenotype that includes reduced levels of phage recombination. Physical mapping experiments showed that this strain has a 78.5-kbp insertion in the rec-2 gene. The rec-2 dependence of phage recombination was reexamined to determine whether the defective phenotype in Rd(DB117)rec- was due to the simple disruption of the rec-2 gene or whether trans-acting factors from the inserted DNA were responsible. Analysis of strains with transposon insertions in the rec-2 gene showed that they were also defective for phage recombination. Therefore, the phage recombination defect was due solely to the disruption of the rec-2 gene. Strain KB6 is proficient for phage recombination but has a defect in genetic transformation resembling that of Rd(DB117)rec-. The transformation defect of KB6 could be complemented by the wild-type rec-2 gene, showing that the rec-2 contributions to genetic transformation and phage recombination were uncoupled in this strain. The rec-2-dependent phenotype of KB6 suggests that the rec-2 gene participates in genetic transformation and phage recombination in different ways.

Expression of functional antigens on neutrophils. Effects of preparation

We have studied how different conditions of cell labelling and isolation affect the expression of five functional antigens on neutrophils from healthy subjects. Fluorescein isothiocyanate conjugated (FITC) antisera specific for the C3bi receptor CR3 (CD11b), aminopeptidase N (CD13), the LPS:LPS binding protein receptor (CD14) and the receptors for human IgG (Fc gamma RII CDw32 and Fc gamma RIII CD16) were incubated with (i) unfixed whole blood at 4 degrees C and at room temperature (RT, approximately 20 degrees C), and the leukocytes prepared for analysis using the Coulter Q-Prep system, (ii) leukocytes which had obtained following the removal of erythrocytes from whole blood by dextran sedimentation and which had been washed or left unwashed at RT, and (iii) leukocytes which had been prepared from whole blood that had been formaldehyde fixed immediately following venesection. The amount of fluorescence associated with the cells was determined by flow cytometry. The expression of CD14 was low under all conditions. However the expression of CD11b, CD16 and CDw32 was significantly higher (p less than 0.05) on neutrophils obtained by dextran sedimentation (n = 4) than on cells which had been fixed with formaldehyde ex vivo; the increase in expression was even greater if the cells had been washed. In contrast, the expression of CD13 on formaldehyde fixed cells was higher than on cells which had been labelled at 4 degrees C or at room temperature and was similar to or slightly lower than that on cells obtained by dextran sedimentation. Increasing the time between 10 and 60 min for which the whole blood was incubated with antisera at RT or at 4 degrees C, resulted in progressive increases in the expression of CD11b and CD13. When neutrophils which had been obtained by dextran sedimentation were incubated with unlabelled antibodies to CD16 or CDw32 and FITC labelled antibodies to CD11b there was a marked increase in the expression of CD11b. Altogether these findings indicate that the analysis of functional molecules on neutrophils (which may be rapidly up-regulated during activation) should be performed under clearly defined and controlled conditions. Dual fluorescence studies may, in some circumstances, produce misleading results.

Leucocyte integrin and CR1 expression on peripheral blood leucocytes of patients with rheumatoid arthritis

Expression of the leucocyte integrins (CD11a, b, c/CD18) and of CD35 (CR1) on leucocytes from the peripheral blood of patients with rheumatoid arthritis (RA) (n = 14) and control subjects (n = 12) was measured by flow cytometry using a rapid fixation and leucocyte preparation procedure. The mean (SE) percentages of lymphocytes expressing CD11a (RA 93.4 (1.7)%; controls 97.2 (1.8)%) and CD18 (RA 91.3 (2.3)%; controls 97.0 (2.6)%) were lower and the percentage of monocytes expressing CD11b (RA 86.9 (11.4)%; controls 78.4 (11.9)%) and CR1 (RA 62.6 (15.5)%; controls 36.6 (17.6)%) were higher in patients with RA than in controls. In addition, the mean fluorescence intensity of CD18 (RA 22.1 (2.3); controls 30.7 (2.5)) on lymphocytes was decreased and that of CD11b (RA 4.5 (0.8); controls 2.9 (0.9)) and CR1 (RA 2.4 (0.4); controls 1.5 (0.5)) on monocytes was increased in patients with RA compared with controls. The functional importance (if any) of the altered expression of the antigens on lymphocytes is not yet known. Altered expression on monocytes is consistent with activation within the circulation.

Large Quasi-Circular Features Beneath Frost on Triton

Specially processed Voyager 2 images of Neptune's largest moon, Triton, reveal three large quasi-circular features ranging in diameter from 280 to 935 kilometers within Triton's equatorial region. The largest of these features contains a central, irregularly shaped area of comparatively low albedo about 380 kilometers in diameter, surrounded by crudely concentric annuli of higher albedo materials. None of the features exhibit significant topographic expression, and all appear to be primarily albedo markings. The features are located within a broad equatorial band of anomalously transparent frost that renders them nearly invisible at the large phase angles (alpha > 90 degrees ) at which Voyager obtained its highest resolution coverage of Triton. The features can be discerned at smaller phase angles (alpha = 66 degrees ) at which the frost only partially masks underlying albedo contrasts. The origin of the features is uncertain but may have involved regional cryovolcanic activity.

A method of preparing blood leucocytes for flow cytometry which prevents upregulation of leucocyte integrins

LeuCAM (CD11/CD18) cell-surface antigens are easily upregulated on cell manipulation ex vivo. A procedure for preparing leucocytes, in which human blood is immediately treated ex vivo with buffered formaldehyde and then the erythrocytes and platelets are removed by lysis and differential centrifugation, has been successfully applied to the analysis of LeuCAM antigen expression by flow cytometry. We show that the increased expression of monocyte CD11/CD18, which occurs when mononuclear leucocytes are separated by a standard Lymphoprep density gradient separation, can be avoided if cells are fixed immediately. Following this fixation polymorphs are unable to upregulate CD11/CD18 in response to fMLP stimulation in vitro. The technique produces lymphocyte, polymorph and monocyte populations that can be clearly defined on the basis of forward scatter and side scatter, and preserves the expression of various surface antigens; the percentages of gated lymphocytes expressing CD3, CD4, and CD8 were similar to those obtained using a commercial fixing and lysis solution. The processing does not render cells permeable to antibodies, as evidenced by our failure to stain cells with antibodies to intracellular antigens. We believed the method to be useful for measuring CD11/CD18 expression on blood leucocytes from normal or pathological specimens and to have application to the measurement of other cells surface antigens which may also be upregulated by the separation procedures.