Who Is Healthy? A Review of How Equine Control Groups Are Defined in Clinical Orthopaedic Research 1999-2021

INTRODUCTION

 Proper identification of healthy subjects is essential in case-control studies. However, standardized definitions of healthy controls are lacking in equine orthopaedic research.

OBJECTIVES

 The aim of this study was to define the non-invasive methods used for selecting healthy control horses in osteoarthritis (OA), desmitis and tendinitis research.

METHODS

 Systematic review. Case-control studies with a healthy control group and longitudinal studies where horses had to be healthy at the start were included. Studies where joints were visualized by arthroscopy or post-mortem examination were excluded.

RESULTS

From 2,472 OA papers and 2,746 desmitis/tendinitis papers, 127 and 84 papers met the inclusion criteria respectively. For OA, 11 methods were identified for defining healthy subjects with a median of three methods used per paper. Dynamic examination, radiographic evaluation and clinical examination were the most frequent. Eight different methods were identified in the desmitis/tendinitis papers with a median of three methods per paper; ultrasonography, clinical- and dynamic examination were the most frequent.

CONCLUSIONS

 Overall, the OA and desmitis/tendinitis studies used similar methods for defining subjects as healthy, but the way the examinations were performed and interpreted was inconsistent. In several studies, healthy controls were not examined for lameness. The most common methods have limitations for detecting horses with early OA, which may have implications for interpretation of results. Standardized use of more sensitive and objective methods could be beneficial.

Nerve growth factor in the equine joint

Nerve growth factor (NGF) is a neurotrophin with many functions. In humans, it is involved in inflammation, nerve growth, apoptosis and pain signalling. Increased concentrations of NGF in synovial fluid has been shown in humans and dogs with osteoarthritis. Despite osteoarthritis being a common problem in horses, no studies have previously been published on NGF in the equine joint. The aim of this study was to quantify NGF in equine synovial fluid from healthy joints, acutely inflamed septic joints and joints with structural changes associated with osteoarthritis. A secondary aim was to identify the localisation of NGF and its two receptors, TrkA and p75^NTR, in healthy and osteoarthritic articular cartilage. NGF concentrations in synovial fluid from osteoarthritic joints (n = 27), septic joints (n = 9) and healthy joints (n = 16) were determined by ELISA. In addition, articular cartilage from osteoarthritic and healthy joints was examined for NGF, TrkA and p75^NTR using immunohistochemistry staining. NGF was present in equine synovial fluid and articular cartilage. Compared to synovial fluid from healthy joints, NGF concentration was higher in synovial fluid from joints with structural osteoarthritic changes (P = 0.032) or acute septic inflammation (P = 0.006). In articular cartilage with severe osteoarthritic changes, there was more abundant positive immunohistochemistry staining for NGF and its receptors than in normal articular cartilage. Further studies should focus on identifying precursor forms of NGF, and on receptor expression and downstream signalling of TrkA and P75^NTR in health and disease.

Glutathione Peroxidase Activity, Plasma Total Antioxidant Capacity, and Urinary F2- Isoprostanes as Markers of Oxidative Stress in Anemic Dogs

Background

Oxidative stress plays a role in the pathophysiology of several diseases and has been documented as a contributor to disease in both the human and veterinary literature. One at‐risk cell is the erythrocyte, however, the role of oxidative stress in anemia in dogs has not been widely investigated.

Hypothesis/Objective

Anemic dogs will have an alteration in the activity of glutathione peroxidase (GPx), a decrease in of total antioxidant capacity (TAC), and an increased concentration of urinary 15‐F₂‐isoprostanes (F₂‐IsoP) when compared to healthy dogs.

Animals

40 client‐owned dogs with anemia (PCV <30%) age‐matched to 40 client‐owned healthy control dogs.

Methods

Prospective, cross‐sectional study. Whole blood GPx activity, plasma TAC, and urinary F₂‐isoprostane concentrations were evaluated in each dog and compared between groups.

Results

Anemic dogs had significantly lower GPx activity (43.1 × 10³ +/‐ 1.6 × 10³ U/L) than did dogs in the control group (75.8 × 10³ +/‐ 2.0 × 10³ U/L; P < 0.0001). The GPx activity in dogs with hemolysis (10³ +/‐ 0.8 × 10³ U/L) was not significantly different (P = 0.57) than in dogs with nonhemolytic anemia (43.5 × 10³ +/‐ 1.1 × 10³ U/L). The TAC concentrations (P = 0.15) and urinary F₂‐isoprostanes (P = 0.73) did not significantly differ between groups.

Conclusions and Clinical Importance

Glutathione peroxidase activity was significantly decreased in anemic dogs indicating oxidative stress. Additional studies are warranted to determine if antioxidant supplementation would improve survival and overall outcome as part of a therapeutic regimen for anemic dogs.

Disparities in auditory physiology and pathology between C57BL/6J and C57BL/6N substrains

C57BL/6 inbred mice are frequently used as models in auditory research, mostly the C57BL/6J and C57BL/6N substrains. Genetic variation and phenotypic disparities between these two substrains have been extensively investigated, but conflicting information exists about differences in their auditory and vestibular phenotypes. Literature-based comparisons are rendered difficult or impossible because most auditory publications do not designate the substrain used. We therefore evaluated commercial C57BL/6N and C57BL/6J mice for their baseline auditory brainstem response (ABR) thresholds at 3 months of age as well as their susceptibility to noise exposure and aminoglycoside antibiotics. Both substrains have similar thresholds at 4 and 12 kHz, but C57BL/6N show significantly higher baseline thresholds at 24 and 32 kHz. Because of these elevated thresholds, the N substrain is unsuitable as a model for drug ototoxicity, which primarily affects high frequencies. Exposure to 2-20 kHz broadband noise for 2 h at 110 dB produced significantly higher threshold shifts in the J substrain. These results suggest caution in the selection of C57BL/6 substrains for auditory research and indicate the need to specify substrains, age and the breeding source in all publications.

Identification and evaluation of improved 4'-O-(alkyl) 4,5-disubstituted 2-deoxystreptamines as next-generation aminoglycoside antibiotics

The emerging epidemic of drug resistance places the development of efficacious and safe antibiotics in the spotlight of current research. Here, we report the design of next-generation aminoglycosides. Discovery efforts were driven by rational synthesis focusing on 4' alkylations of the aminoglycoside paromomycin, with the goal to alleviate the most severe and disabling side effect of aminoglycosides-irreversible hearing loss. Compounds were evaluated for target activity in in vitro ribosomal translation assays, antibacterial potency against selected pathogens, cytotoxicity against mammalian cells, and in vivo ototoxicity. The results of this study produced potent compounds with excellent selectivity at the ribosomal target, promising antibacterial activity, and little, if any, ototoxicity upon chronic administration. The favorable biocompatibility profile combined with the promising antibacterial activity emphasizes the potential of next-generation aminoglycosides in the treatment of infectious diseases without the risk of ototoxicity.

IMPORTANCE

The ever-widening epidemic of multidrug-resistant infectious diseases and the paucity of novel antibacterial agents emerging from modern screening platforms mandate the reinvestigation of established drugs with an emphasis on improved biocompatibility and overcoming resistance mechanisms. Here, we describe the preparation and evaluation of derivatives of the established aminoglycoside antibiotic paromomycin that effectively remove its biggest deficiency, ototoxicity, and overcome certain bacterial resistance mechanisms.

Metformin protects against gentamicin-induced hair cell death in vitro but not ototoxicity in vivo

Metformin (N,N-dimethylbiguanidine) is a widely employed oral hypoglycemic agent for the management of type 2 diabetes mellitus. Its antioxidant properties and safe clinical use raise the possibility of preventing gentamicin-induced hearing loss in patients. Therefore, we screened the usefulness of metformin against gentamicin toxicity in murine cochlear explants and in the guinea pig in vivo. We confirmed in organ culture that metformin blocks the gentamicin-induced translocation of endonuclease G into the nucleus of outer hair cells and attenuates hair cell loss. In vivo, gentamicin treatment with 80, 100, or 130mg/kg body weight for 14 days induced significant threshold shifts as determined by auditory brain stem responses. Metformin (30, 75, or 100mg/kg for 14 days) was well tolerated without any indication of auditory side effects. However, co-administration of metformin with gentamicin in various permutations did not prevent loss of auditory function. On the contrary, combined treatment at higher dosages aggravated the gentamicin-induced threshold shifts and caused additional adverse reactions including body weight loss and premature deaths in some animals. These results caution against the use of metformin co-treatment with aminoglycosides and confirm the need for in vivo studies in order to evaluate potentially protective agents selected by in vitro screens.

Designer aminoglycosides that selectively inhibit cytoplasmic rather than mitochondrial ribosomes show decreased ototoxicity: a strategy for the treatment of genetic diseases

There is compelling evidence that aminoglycoside (AG) antibiotics can induce the mammalian ribosome to suppress disease-causing nonsense mutations and partially restore the expression of functional proteins. However, prolonged AG treatment can cause detrimental side effects in patients, including most prominently, ototoxicity. Recent mechanistic discussions have considered the relative contributions of mitochondrial and cytoplasmic protein synthesis inhibition to AG-induced ototoxicity. We show that AGs inhibit mitochondrial protein synthesis in mammalian cells and perturb cell respiration, leading to a time- and dose-dependent increase in superoxide overproduction and accumulation of free ferrous iron in mitochondria caused by oxidative damage of mitochondrial aconitase, ultimately leading to cell apoptosis via the Fenton reaction. These deleterious effects increase with the increased potency of AG to inhibit the mitochondrial rather than cytoplasmic protein synthesis, which in turn correlates with their ototoxic potential in both murine cochlear explants and the guinea pig in vivo. The deleterious effects of AGs were alleviated in synthetic derivatives specially designed for the treatment of genetic diseases caused by nonsense mutations and possessing low affinity toward mitochondrial ribosomes. This work highlights the benefit of a mechanism-based drug redesign strategy that can maximize the translational value of "readthrough therapy" while mitigating drug-induced side effects. This approach holds promise for patients suffering from genetic diseases caused by nonsense mutations.

Silencing near tRNA genes is nucleosome-mediated and distinct from boundary element function

Transfer RNA (tRNA) genes and other RNA polymerase III transcription units are dispersed in high copy throughout nuclear genomes, and can antagonize RNA polymerase II transcription in their immediate chromosomal locus. Previous work in Saccharomyces cerevisiae found that this local silencing required subnuclear clustering of the tRNA genes near the nucleolus. Here we show that the silencing also requires nucleosome participation, though the nature of the nucleosome interaction appears distinct from other forms of transcriptional silencing. Analysis of an extensive library of histone amino acid substitutions finds a large number of residues that affect the silencing, both in the histone N-terminal tails and on the nucleosome disk surface. The residues on the disk surfaces involved are largely distinct from those affecting other regulatory phenomena. Consistent with the large number of histone residues affecting tgm silencing, survey of chromatin modification mutations shows that several enzymes known to affect nucleosome modification and positioning are also required. The enzymes include an Rpd3 deacetylase complex, Hos1 deacetylase, Glc7 phosphatase, and the RSC nucleosome remodeling activity, but not multiple other activities required for other silencing forms or boundary element function at tRNA gene loci. Models for communication between the tRNA gene transcription complexes and local chromatin are discussed.

Tachypnea and antipyresis in febrile horses after sedation with alpha-agonists

BACKGROUND

Signs of tachypnea after sedation of febrile horses with alpha2-agonists have been noted previously but have not been further investigated.

OBJECTIVES

To examine the effects of xylazine and detomidine on respiratory rate and rectal temperature in febrile horses and to investigate if either drug would be less likely than the other to cause changes in these variables.

ANIMALS

Nine febrile horses and 9 healthy horses were included in the study.

METHODS

Horses were randomly assigned to sedation with xylazine 0.5 mg/kg or detomidine 0.01 mg/kg. Heart rate and respiratory rate were recorded before sedation and at 1, 3, and 5 minutes after injection. Hourly measurements of rectal temperature were performed starting before sedation.

RESULTS

All febrile horses experienced an episode of tachypnea and antipyresis after sedation. Rectal temperature in the febrile group was significantly lower at 1, 2, and 3 hours after sedation. In several measurements, the decrease was >1 degrees C. Respiratory rate in the febrile group was significantly increased after sedation. All febrile horses were breathing>40 breaths/min and 3 horses>100 breaths/min 5 minutes after sedation. No differences were noted between the 2 treatments. No significant changes in respiratory rate or temperature were noted in the reference group.

CONCLUSIONS AND CLINICAL IMPORTANCE

Febrile horses can become tachypneic after sedation with detomidine or xylazine. The antipyretic properties of alpha2-agonists need consideration when evaluating patients that have been sedated several hours before examination.

Clinical efficacy of capecitabine as first-line chemotherapy in metastatic breast cancer--how low can you go?

Sixty-three patients received capecitabine at 1000 mg/m2 twice daily every 2 out of 3 weeks as first-line treatment for advanced disease at our institution. Forty-five patients (71%) had previously received adjuvant or neoadjuvant chemotherapy. The median number of capecitabine cycles administered was 5(1-40). Forty-eight patients had measurable disease with response rate (RR) of 29%. The median time to progression (TTP) was 18(2-122) weeks. Seven patients (11%) had TTP of >1 yr, four of whom received more than 10(24-40) cycles of capecitabine. Thirty-seven percent of patients still needed dose reductions. Our retrospective audit is consistent with a previously published study which used a higher starting dose of capecitabine as first-line chemotherapy. For a subgroup of patients, capecitabine can result in a long TTP with minimal toxicity. The benefit of continuing capecitabine beyond a fixed number of cycles should be investigated further. Schedules using even lower doses of capecitabine for longer periods may also be of interest.

Aromatase inhibition and very low dose estradiol add-back: A pilot study for novel breast cancer prevention

1014

Background: Aromatase inhibitors (AIs) are important agents for the treatment of hormone receptor positive breast cancer in post menopausal women. They are being assessed as chemopreventives of breast cancer in large clinical trials, but there are known issues of tolerability notably affecting bone. It is possible that decreasing, but not abolishing, circulating estradiol levels may reduce breast cancer risk without such side effects. We have undertaken a novel pilot study to establish whether healthy volunteers on an AI could be delivered very low dose estradiol replacement to a predictable serum level of 10–20 pmol/L using a transdermal patch, and whether this would reverse changes in the bone resorption biomarker CTx. Methods: Ten healthy postmenopausal women with normal estradiol levels received letrozole 2.5mg/day for 16 weeks. From weeks 6–16 they were also given a quarter of Estraderm MX25 transdermal patch (6.25 μg of estradiol) replaced, twice weekly. Fasting blood samples were taken at baseline, 6, 10, 12, 14 and 16 weeks for estradiol, FSH, LH, SHBG and CTx. Results: Serum estradiol levels fell to <3pmol/L at 6 weeks consistent with AI therapy. The quarter patch successfully replaced estradiol levels to a median of 12pmol/L although there was marked inter and intrasubject variability. FSH rose significantly with AI therapy with no appreciable change in SHBG or LH. There is encouraging evidence that CTx levels which increased with AI (p=0.076) can be corrected with low dose estradiol replacement although this did not reach statistical significance in this initial group. We continue to collect data on a further 8 subjects already recruited into the study. Conclusions: A quarter of Estraderm MX25 transdermal patch can be used to provide a serum estradiol level of 10–20 pmol/l in postmenopausal women given an AI. Further data will confirm whether this novel approach to chemoprevention can reverse the negative impact of AIs on bone metabolism and be suitable for extending to a full chemoprevention trial.

[Table: see text]

No significant financial relationships to disclose.

Staging of small cell lung cancer (SCLC): Comparison of two criteria by survival analysis

17030

Background: Consistent staging of SCLC is pertinent to the selection and evaluation of treatment regimens. The Veterans Administration Lung Study Group (VALG) defines patients with limited disease (LD) as those with tumor limited to one hemithorax. In contrast, the International Association for the Study of Lung Cancer (IASLC), basically a TNM method, defines limited disease as those with no distant metastases. We assessed the survival of intermediate patients (ID), defined as those who qualified as LD by the IASLC but not the VALG criteria. Methods: A retrospective chart review was done on 252 patients consecutively diagnosed with SCLC between 1990 and 2004 at a Northern California hospital. Kaplan Meier analysis and log-rank tests were used to compare the survival of ID and LD patients. We also compared survival of both ID and LD to patients with extensive disease (ED). Multivariate Cox regression analysis was used to incorporate clinically relevant data. Bonferroni adjustment was made for multiple comparisons. Results: We defined 93 patients as LD, 32 as ID and 127 as ED. Median survival of patients with ID was 12 months (95% CI 9–16 months) and for LD 11 months (95% CI 9–13 months). Median survival for patients with ED was 6 months (95% CI 4–7 months) and significantly shorter (P < .0001) than either ID or LD. Conclusions: The present study questions the inclusiveness of the VALG definition of LD concurs with prior findings from Germany (Lung Cancer 37:271, 2002). SCLC patients should be staged by the IASLC criteria when being evaluated for treatment regimens.

No significant financial relationships to disclose.

Clinical efficacy of capecitabine as first-line chemotherapy in metastatic breast cancer

10727

Background: Capecitabine is commonly used in metastatic breast cancer (MBC), but there are limited data on its efficacy in the first-line setting. The clinical efficacy of capecitabine monotherapy was evaluated in our institution. Methods: Patients who received capecitabine monotherapy (starting dose 1 g/m2 twice daily every 2 out of 3 weeks) between April 2001 and April 2005 as first-line treatment for advanced disease were retrospectively identified from our prospectively maintained database. Endpoints included response rate (RR), response duration, time to progression (TTP) and overall survival (OS). Results: 63 patients were evaluated. The median age was 57 (30–79) years. The sites of disease were soft tissue and/or bone only in 24 (38%) patients, and involved visceral sites in 39 (62%) patients. 45 (71%) patients had previously received adjuvant or neoadjuvant chemotherapy. The median number of cycles administered was 5 (1–40). 48 (76%) had measurable disease with a RR of 29% (14/48). Chemotherapy-naive patients with measurable disease had a RR of 33% (5/15), while patients previously exposed to neoadjuvant or adjuvant chemotherapy had a RR of 27% (9/33). The median response duration was 24(9–68) weeks. The median TTP was 18 (range 2–122) weeks. However 12(19%) had a TTP of 9 months or more, including 7 (11%) with a TTP of >1 year (14–28 months). Of these, 6/7 were oestrogen receptor +ve and 5/7 had bone and/or soft tissue disease only. 21 (33%) patients developed disease progression on treatment, and response was not evaluable in 4 (6%) patients who stopped capecitabine after 2 or fewer cycles due to medical co-morbidities. Conclusions: These audit results on first line capecitabine monotherapy in MBC are consistent with a previously published study(1). The overall RR may be less than for anthracyclines and taxanes (generally 30–50%) in this setting, but for a subgroup of patients with predominantly soft tissue/bone disease capecitabine can result in prolonged TTP with minimal toxicity. This should be evaluated further in a randomized clinical trial. References 1. O’Shaughnessey JA et al. Ann Oncol 2001 Sept; 12 (9): 1247–54.

[Table: see text]

Caution: Vaginal estradiol appears to be contraindicated in postmenopausal women on adjuvant aromatase inhibitors

BACKGROUND

Aromatase inhibitors (AI) are increasingly used in early breast cancer and there is a growing interest in associated long-term side-effects of profound estrogen suppression. Urogenital side-effects due to atrophic vaginitis are often managed with vaginal estrogen preparations. These are generally perceived to result in minimal systemic absorption of estrogen. We followed serum estradiol, follicle stimulating hormone (FSH) and luteinising hormone (LH) levels in seven postmenopausal women using vaginal estrogen preparations whilst on AIs for breast cancer.

PATIENTS AND METHODS

Serum was analysed for estradiol, FSH and LH at baseline then 2, 4, 7-10 and 12 weeks since commencement of vaginal estradiol. Estradiol was measured on an assay specifically developed for measuring low levels in postmenopausal women.

RESULTS

Serum estradiol levels rose from baseline levels < or = 5 pmol/l consistent with AI therapy to a mean 72 pmol/l at 2 weeks. By 4 weeks this had decreased to < 35 pmol/l in the majority (median 16 pmol/l) although significant further rises were seen in two women.

CONCLUSIONS

The vaginal estradiol tablet Vagifem significantly raises systemic estradiol levels, at least in the short term. This reverses the estradiol suppression achieved by aromatase inhibitors in women with breast cancer and is contraindicated.

Phase II study of oral capecitabine in patients with hormone-refractory prostate cancer

BACKGROUND

Currently available treatment for hormone refractory prostate cancer is limited in efficacy and associated with significant toxicity. This phase II study was performed to assess the efficacy of the oral fluoropyrimidine capecitabine in advanced prostate cancer.

PATIENTS AND METHODS

Patients who had a rising prostate-specific antigen (PSA) despite androgen withdrawal, but who remained free from cancer-related symptoms. In total, 14 patients received oral capecitabine 1250 mg/m2 twice daily for two weeks of a three-week cycle. Tumour response was assessed using serum PSA measurement at 3-weekly intervals and, where present, imaging of soft tissue metastases.

RESULTS

One of 14 patients experienced a partial response as assessed by both PSA and imaging of liver metastases. In seven other patients (50%), treatment decreased the rate of PSA rise. The duration of PSA stabilisation was generally short, but in 5/14 patients (36%) was sustained beyond 18 weeks, and in one patient to 24 weeks. Toxicity was significant but manageable, the most common adverse events being nausea, mucositis and hand-foot syndrome, each occurring in 50% of patients. Other common side effects were diarrhoea and lymphopenia. All toxicities were grade 1 or 2, except for grade 3 hand-foot syndrome occurring in one patient, and no dose reduction was required because of toxicity.

CONCLUSION

Capecitabine has limited activity as a single agent in prostate cancer, but appears to modulate tumour biology. Considering the added convenience of oral administration, these results support further evaluation of combinations containing capecitabine in hormone-refractory prostate cancer.

Signet Ring Cell Carcinoma in the Prostate

Metastases to the prostate gland are rare and often found in the context of widespread metastatic disease. We report an unusual case of primary gastric signet ring cell adenocarcinoma (SRCC) diagnosed over 1 year after treatment for metastatic disease in the prostate.

Evaluation of psychosocial measures for understanding weight-related behaviors in pregnant women

The greatest weight gain for US. women occurs during the childbearing years of 25 to 34, and many obese women attribute their adult weight gain to childbearing. Few studies have examined psychosocial influences on women's behaviors during pregnancy, in part because of the lack of valid and reliable measures of psychosocial constructs relevant to pregnant women. Based on existing theory and an in-depth interview study, the psychosocial constructs of locus of control, self-efficacy, body image, feelings about motherhood, and career orientation were identified. Scales for each construct were constructed by drawing items from existing validated scales and writing items based on the in-depth interviews; their content validity assessed using factor analysis with oblique rotation and their reliability using Cronbach's alpha. Construct validity was assessed by examining the associations between scale scores and preexisting conditions of participants. Data for evaluating the scales came from a study of 622 pregnant women in a rural health care system who completed questionnaires and whose medical records were audited. Cronbach's alpha of the scales ranged from 0.73 to 0.89. Scale scores were strongly associated with lifestyle behaviors, body weight, and demographic characteristics of the participants. The analysis provides evidence of the validity of measures of psychosocial factors related to health behaviors of pregnant women. These measures should be useful in studying weight-related behaviors in pregnant women.

A CBF5 mutation that disrupts nucleolar localization of early tRNA biosynthesis in yeast also suppresses tRNA gene-mediated transcriptional silencing

In the budding yeast, Saccharomyces cerevisiae, actively transcribed tRNA genes can negatively regulate adjacent RNA polymerase II (pol II)-transcribed promoters. This tRNA gene-mediated silencing is independent of the orientation of the tRNA gene and does not require direct, steric interference with the binding of either upstream pol II factors or the pol II holoenzyme. A mutant was isolated in which this form of silencing is suppressed. The responsible point mutation affects expression of the Cbf5 protein, a small nucleolar ribonucleoprotein protein required for correct processing of rRNA. Because some early steps in the S. cerevisiae pre-tRNA biosynthetic pathway are nucleolar, we examined whether the CBF5 mutation might affect this localization. Nucleoli were slightly fragmented, and the pre-tRNAs went from their normal, mostly nucleolar location to being dispersed in the nucleoplasm. A possible mechanism for tRNA gene-mediated silencing is suggested in which subnuclear localization of tRNA genes antagonizes transcription of nearby genes by pol II.

Novel nonpeptidic inhibitors of peptide deformylase

A novel series of nonpeptidic compounds structurally related to the known anticholesteremic thyropropic acid were found to inhibit Escherichia coli peptide deformylase (PDF), with IC50 values in the low-micromolar range. Kinetic analysis of [4-(4-hydroxyphenoxy)-3,5-diiodophenyl]acetic acid reveals competitive inhibition, with a Ki value of 0.66 +/- 0.007 microM. A structure-activity relationship study demonstrates that the carboxylate is required for activity, while the distal phenolic function can be methylated without significant effect. Either decreasing the number of iodine atoms on the molecule to one or increasing the number of iodine atoms to four results in the loss of an order of magnitude in potency. These compounds are the first nonpeptidic inhibitors disclosed and represent a template from which better inhibitors might be designed.

Nucleolar localization of early tRNA processing

There is little information as to the location of early tRNA biosynthesis. Using fluorescent in situ hybridization in the budding yeast, Saccharomyces cerevisiae, examples of nuclear pre-tRNAs are shown to reside primarily in the nucleoli. We also probed the RNA subunit of RNase P. The majority of the signal from RNase P probes was nucleolar, with less intense signals in the nucleoplasm. These results demonstrate that a major portion of the tRNA processing pathway is compartmentalized in nucleoli with rRNA synthesis and ribosomal assembly. The spatial juxtaposition suggests the possibility of direct coordination between tRNA and ribosome biosynthesis.

Hunger and food insecurity in the elderly: its nature and measurement

To better understand the nature of food insecurity in the elderly and to improve its measurement, in-depth interviews were conducted with 41 urban Black and rural White elderly in 35 households, followed by telephone administration of commonly used measures of food insecurity in 24 of these elderly. Elderly food insecurity appears to follow a progression of severity, beginning with compromised diet quality, followed by food anxiety, socially unacceptable meals, use of emergency food strategies, and finally actual hunger. The five quantitative measures tested were compared to each elderly person's food insecurity status based on the in-depth interview. All measures had reasonable specificity, and good sensitivity for those experiencing severe food insecurity. However, the Cornell-Radimer, Community Childhood Hunger Identification Project (CCHIP) and Nutrition Screening Initiative (NSI) measures appeared more sensitive than the USDA food sufficiency or Urban Institute measures in correctly identifying those in the lesser stages of food insecurity.

Potent antimitotic and cell growth inhibitory properties of substituted chalcones

A series of substituted chalcones was synthesised and screened for cytotoxic activity against the K562 human leukaemia cell line. (E)-3-(3"-Hydroxy-4"-methoxyphenyl)-2-methyl-1-(3',4',5'- trimethoxyphenyl)-prop-2-en-1-one [IC50 (K562) 0.21 nM] was found to be the most active. A relationship between the conformation and cytotoxicity of the chalcones is discussed.

Questionnaire-based measures are valid for the identification of rural households with hunger and food insecurity

This study assessed the validity of questionnaire-based measures for the identification of rural households with hunger and food insecurity. Data used were from a 1993 survey of 193 households with women and children living at home in a rural county. Two interviews provided data on demographics, factors contributing to food insecurity, coping strategies, fruit and vegetable consumption, disordered eating behaviors, height, weight, dietary recall and household food-stores inventory. This information was used to develop a definitive criterion measure for hunger and food insecurity to compare with hunger and food insecurity items from Radimer/Cornell, the Community Childhood Hunger Identification Project (CCHIP) and the Third National Health and Nutrition Examination Survey (NHANES III). The Radimer/Cornell and CCHIP questionnaire-based measures had good specificity (i.e., percentage of truly food secure correctly classified; 63-71%) and excellent sensitivity (i.e., percentage of truly food insecure correctly classified; 84-89%) when compared with the criterion measure. Estimates of the prevalence of household food insecurity from the criterion, Radimer/Cornell and CCHIP measures were almost identical. The overall agreement of the Radimer/Cornell and CCHIP measures was very good. These measures can be validly used to screen for hunger and food insecurity among rural households similar to those studied and to target subpopulations for food programs. The NHANES III item alone had excellent specificity but poor sensitivity, and underestimated prevalence.

Relationship of hunger and food insecurity to food availability and consumption

OBJECTIVE

To describe the relationship of new measures of hunger and food insecurity to household food supplies and individual food and nutrient intake.

DESIGN AND SETTING

A questionnaire containing the Radimer/Cornell hunger and food insecurity items and questions on eating patterns and the frequency of fruit and vegetable consumption was administered to subjects during a personal interview in their homes. A 24-hour diet recall and a household food inventory were conducted at the initial interview and at a follow-up visit.

SUBJECTS

Participants were 193 women drawn from a random sample of 308 women who had completed a previous health census in a rural New York State county. Subjects' ages ranged from 15 to 40 years. All had children living at home and less than 16 years of education.

STATISTICAL ANALYSES

Regression analysis was used to test for linear trends across food insecurity groups for the household food inventory scores and for the frequency of consumption of fruits and vegetables. t Tests were used to assess differences between the food secure and food insecure groups for nutrient and food group means. A chi 2 test for trend was used to examine differences in the distribution of nutrient and fruit and vegetable intake between the food secure and food insecure groups.

RESULTS

A significant decrease in the frequency of consumption of fruits and vegetables and the amount of food in the household and a significant increase in scores indicative of disordered eating patterns were associated with a worsening of food insecurity status. Potassium and fiber intake and fruit consumption differed significantly between the food secure and food insecure groups. The percentage of respondents consuming less than the Recommended Dietary Allowance for vitamin C and fewer than five fruits and vegetables per day was significantly greater among food insecure respondents than food secure respondents.

APPLICATIONS/CONCLUSIONS

The quantity of food available in households and consumption of fruits and vegetables decreased with increasingly severe problems with food insecurity and hunger. In this rural population, the Radimer/ Cornell measures were useful in identifying households experiencing food insecurity and providing information about the nature of the food supply and the dietary intake problems experienced by food insecure households and persons, suggesting that these measures may be useful on community surveys designed to examine food insecurity issues.

Validation of the Radimer/Cornell measures of hunger and food insecurity

Hunger and food insecurity have been identified as core indicators of an individual's nutritional state that should be assessed in nutrition surveillance activities. Such an assessment requires a valid measure of these phenomena. This paper describes further work on the construction of measures of hunger and food insecurity based on the Radimer/Cornell items and provides an assessment of their validity. A random sample survey of 193 households with women and children living at home was conducted in 1993 in a rural county in New York State. A questionnaire containing the Radimer/Cornell hunger and food insecurity items, information about demographic characteristics, frequency of fruit and vegetable consumption, and household food supplies was administered to subjects. Measures were constructed that identified households experiencing household- and individual-level food insecurity and households with hungry children. The construct and criterion-related validity of the measures was assessed. In relation to criterion-related validity, as food insecurity worsened, there was a significant and progressive increase in the percentage of subjects participating in food programs and having low income, education and employment and a significant decline in average household food availability and fruit and vegetable consumption. These results support the validity of the Radimer/Cornell measures and illustrate their ability to differentiate among groups of households experiencing increasingly severe food insecurity and hunger.

Stress, anxiety, depression, and physical illness in college students

The interrelationships among measures of stress, anxiety, depression, and physical illness in a proportional sample of college undergraduates (N = 184) were examined. Significant correlations were found in the stress-illness, anxiety-illness, depression-illness, and anxiety-depression relationships. Partial correlations demonstrated that the stress-illness relationship remained significant, though lowered, when first anxiety and then depression were held constant. In the second phase of the research the indices of stress, anxiety, depression, and illness were predicted to vary by both year in school and gender within this sample. Significant differences in reported stress and anxiety by year in school and in reported illness incidence by gender were found. Possible ties between these results and research on coping, social support, and gender roles are discussed.

Weight loss on a low-fat diet: consequence of the imprecision of the control of food intake in humans

This study examined the degree to which humans compensate for a reduction in dietary fat by increasing energy intake. Thirteen females were randomly assigned to either a low-fat diet (20-25% of calories as fat) or a control diet (35-40% fat) for 11 wk. After a 7-wk washout period, the conditions were reversed for another 11 wk. Energy intake on the low-fat diet gradually increased by 0.092 kJ/wk resulting in a total caloric compensation of 35% by the end of the 11-wk treatment period. This failure to compensate calorically on the low-fat diet resulted in a deficit of 1.22 kJ/d and a weight loss of 2.5 kg in 11 wk, twice the amount of weight lost on the control diet. These results demonstrate that body weight can be lost merely by reducing the fat content of the diet without the need to voluntarily restrict food intake.

Lymphocyte proliferation responses after exercise in men: fitness, intensity, and duration effects

This study investigated the effects of intensity and duration of exercise on lymphocyte proliferation as a measure of immunologic function in men of defined fitness. Three fitness groups--low [maximal O2 uptake (VO2max) = 44.9 +/- 1.5 ml O2.kg-1.min-1 and sedentary], moderate (VO2max = 55.2 +/- 1.6 ml O2.kg-1.min-1 and recreationally active), and high (VO2max = 63.3 +/- 1.8 ml O2.kg-1.min-1 and endurance trained)--and a mixed control group (VO2max = 52.4 +/- 2.3 ml O2.kg-1.min-1) participated in the study. Subjects completed four randomly ordered cycle ergometer rides: ride 1, 30 min at 65% VO2max; ride 2, 60 min at 30% VO2max; ride 3, 60 min at 75% VO2max; and ride 4, 120 min at 65% VO2max. Blood samples were obtained at various times before and after the exercise sessions. Lymphocyte responses to the T cell mitogen concanavalin A were determined at each sample time through the incorporation of radiolabeled thymidine [( 3H]TdR). Despite differences in resting levels of [3H]TdR uptake, a consistent depression in mitogenesis was present 2 h after an exercise bout in all fitness groups. The magnitude of the reduction in T cell mitogenesis was not affected by an increase in exercise duration. A trend toward greater reduction was present in the highly fit group when exercise intensity was increased. The reduction in lymphocyte proliferation to the concanavalin A mitogen after exercise was a short-term phenomenon with recovery to resting (preexercise) values 24 h after cessation of the work bout. These data suggest that single sessions of submaximal exercise transiently reduce lymphocyte function in men and that this effect occurs irrespective of subject fitness level.

Exercise and blood lymphocyte subset responses: intensity, duration, and subject fitness effects

This study examined the effect of exercise intensity and duration on the percent blood lymphocytes in men of low [LF; maximal O2 uptake (VO2max) less than 50 ml.kg-1.min-1 and sedentary], moderate (MF; VO2max = 50-60 ml.kg-1.min-1 and recreationally active), and high (HF; VO2max greater than 60 ml.kg-1.min-1 and recent training history) fitness. Thirty healthy adult men (aged 20-31 yr) participated in four randomly ordered cycle ergometer rides: ride 1 (65% VO2max, 30 min), ride 2 (30% VO2max, 60 min), ride 3 (75% VO2max, 60 min), and ride 4 (65% VO2max, 120 min). Blood samples were drawn at various times before and after the exercise sessions. Lymphocyte subsets were determined by flow cytometry using monoclonal antibodies for total T (CD3+), T-helper (CD4+), and T-suppressor (CD8+) lymphocytes and for a subset of cells expressing a natural killer (NK) cell antigen (Leu7+). Plasma catecholamines were assayed to determine exercise stress. There were sharp reductions (P less than 0.01) in the percentage of pan-T and T-helper lymphocytes immediately after exercise across all fitness levels; the magnitude of this reduction was greatest after the highest intensity (ride 3) or longest duration (ride 4) work. In contrast, the absolute number of T and T-helper cells tended to increase after exercise and significantly so in the HF subjects (P less than 0.005). There was no significant effect of exercise or subject fitness category on the percentage of T-suppressor lymphocytes, although the absolute numbers of this subset increased significantly after exercise in LF subjects. Marked increases (P less than 0.01) in the percentage of NK cells occurred immediately after exercise at all intensities and durations tested; numerical increases in total NK cells were significant in all fitness groups after the highest intensity work (ride 3; P less than 0.005). Irrespective of whether the changes were expressed as percentage or total numbers, recovery to base line occurred at 30 min after exercise. The results suggest that the exercise effect on blood lymphocyte subset percentages in men is transient and occurs across all fitness levels. Concomitant changes in plasma catecholamine concentrations are only weakly associated with these lymphocyte subset percentage responses to exercise. Furthermore, this study shows that the exercise-induced changes in lymphocyte percentages do not consistently reflect changes in the absolute numbers of cells.

Inhibition of human tumor cell induced platelet aggregation by antibodies to platelet glycoproteins Ib and IIb/IIIa

Tumor cell induced platelet aggregation was shown to be inhibited in a dose dependent manner by preincubation of human platelets with antibodies to platelet glycoprotein Ib and the IIb/IIIa complex. Combination of antibody to Ib and antibody to the IIb/IIIa complex at concentrations which produced half maximal inhibition of platelet aggregation alone caused complete inhibition of tumor cell induced platelet aggregation. Antibodies to platelet glycoproteins Ib and the IIb/IIIa complex also inhibited platelet synthesis of thromboxane A2, but not synthesis of 12-hydroxyeicosatrienoic acid. Inhibition of tumor cell induced platelet aggregation with antibodies against platelet glycoproteins suggests a role for these glycoproteins in tumor cell-platelet interactions and possibly platelet facilitated tumor cell metastasis.

Hemoglobin New York associated with alpha-thalassemia

A Chinese family is described in which 6 members possess both the beta-chain hemoglobin variant Hb New York and alpha-thalassemia trait. The frequency of this combination may be greater than hitherto realized because Hb New York may easily be missed on routine hemoglobin electrophoresis.

Human erythrocyte carbonic anhydrase polymorphism in Kenya

In this study, 1736 Western Kenyans were examined for red cell carbonic anhydrase (CA) variants. No CA I variants were detected, but the CA II2 isozyme was found with a calculated gene frequency of 0.054.

The unstable Hb Genova (beta 28Leu replaced by Pro) in an East African Family. Family study and the effect of splenectomy

A fifth family with the unstable Hb Genova is reported from Kenya, East Africa. This almost certainly represents an independent mutation. The beneficial effect of splenectomy has been carefully assessed in one member of the family.