Novel aspects to the structure of rabbit articular cartilage

Applying cryo and modified chemical preparation techniques, mainly for scanning electron microscopy, revealed entirely new aspects to the structure of the radial zone of rabbit tibial plateau articular cartilage. The aggrecan component of the extracellular matrix was contained radially in columns, each with a diameter of 1-3 mm, by a tightly packed matrix of collagen fibrils. The collagen fibrils were arranged radially, some straight and others in an opposed spiral arrangement, with regularly repeating patterns. This organization existed in the regions surrounding the columns of chondrocytes, known as chondrons. The load bearing property of the tissue was explained by the directed flow and containment of the interstitial fluid, modulated by the protein-carbohydrate complexes, along these collagen bounded tubular structures. The reason why such a structure has not been described previously may be that it is not retained by aldehyde fixation followed by dehydration, the method commonly used for tissue preparation for electron microscopy.

Neurobehavioral symptoms in childhood closed-head injuries: changes in prevalence and correlates during the first year postinjury

OBJECTIVE

To examine changes in the prevalence and correlates of neurobehavioral symptoms during the first year following childhood closed-head injuries (CHIs).

METHODS

Participants included 31 children with severe CHIs, 38 with moderate CHIs, and 53 with orthopedic injuries (OIs). Children and their families were assessed shortly after injury and at 6- and 12-month follow-ups. Parents rated 15 symptoms classified as either cognitive/somatic (C/S) or emotional/behavioral (E/B).

RESULTS

Both kinds of symptoms were more common in the CHI groups than in the OI group. C/S symptoms declined in the CHI groups over time, whereas E/B symptoms became relatively more common. Measures of injury severity, children's premorbid behavioral adjustment, and concurrent cognitive functioning predicted C/S symptoms. E/B symptoms were predicted by injury severity, concurrent cognitive functioning soon after the injury, and concurrent parent and family functioning later in time. Both types of symptoms contributed to the prediction of perceived family burden, with the relationships strengthening over time.

CONCLUSIONS

The findings indicate that the prevalence and correlates of neurobehavioral symptoms in childhood CHIs vary as a function of symptom type and time since injury.

Explaining drug spending trends: does perception match reality?

Several recent studies have made clear that drug expenditures are rising more rapidly than other health care spending. What has not been clear, however, is how much drug spending is driven by price rather than volume and whether volume increases are appropriate. This DataWatch takes a closer look at the components and drivers of drug spending using large claims databases from managed care and employer-sponsored health benefit plans. In both environments this study found volume, not price, to be the largest driver of drug spending for seven diseases studied. For four of the diseases, we review the clinical issues that may have influenced volume growth.

Freeze-substitution of rabbit tibial articular cartilage reveals that radial zone collagen fibres are tubules

Investigations of the micromorphology of rabbit tibial articular cartilage using scanning and transmission electron microscopy revealed that the collagenous elements in the tissue form fluid-containing tubular structures. The commonly described radial or deep zone longitudinal fibres were found to be tubular structures with internal diameters of 1-2 microm. The walls of the tubules were composed of tightly packed fibrils of collagen. The tangential zone, close to the tibial plateau, was composed mainly of a spongy arrangement of collagen fibrils, containing bunches of tangentially lying small (< 1 microm) diameter tubules. The application of conventional chemical fixation techniques resulted in the fine detail of this tissue being obscured. When the tissue was frozen, followed by cryo-scanning electron microscopy or freeze-drying, prior to observation in the scanning electron microscope the tubule structures were not obviously present. It was only by applying freeze-substitution techniques, followed by critical point drying or resin embedding, that the structure was revealed clearly. Segregation of water into ice crystals did occur during the freezing process, but the formation of those crystals played no part in creating the tubular morphology observed. A similar structure was still revealed following pre-treatment with glycerol, methanol or Triton X-100, provided that concentration of these additives was not too high. The walls of the tubules in the radial region were composed of straight, longitudinally arranged as well as helically arranged, 30 nm diameter fibrils. The lumen of the tubules appears to be lined by a circumferentially arranged array of approximately 10 nm diameter fibres, spaced at regular intervals of 50-70 nm.

Efficient discovery of inhibitory ligands for diverse targets from a small combinatorial chemical library of chimeric molecules

Living systems are mainly composed and regulated by compounds in four biochemical classes and their polymers-nucleotides, carbohydrates, lipids, and amino acids. Early combinatorial chemistry libraries consisted of peptides. The present report describes the general bioactivity and biophysical properties of a combinatorial chemical library that used glyco, nucleotidyl, and lipid building blocks. The resulting chimeric combinatorial library of 361 compounds had a confirmed cumulative hit rate of 0.16%, which is 8-fold higher than a commonly claimed industrial benchmark of 0. 02%. It produced 7 structurally confirmed hits for a third of 12 proprietary drug discovery projects, and these comprised a variety of molecular targets. Diversity analyses demonstrated that despite the small number of compounds, a wider range of diversity space was covered by this library of biochemical chimeras than by a branched tripeptide library of the same size and similar generic formula.

HIV testing practices of Zimbabwean physicians and their perspectives on the future use of rapid on-site tests

To improve HIV testing procedures, rapid on-site HIV tests have been introduced in Zimbabwe. At present, little is known about physicians' perspectives on the potential use of rapid tests in their clinics or about their current laboratory-based testing practices. In a sample of 63 general practitioners in Harare, this study found physicians were generally testing individuals, not couples, and an important reason for suggesting a patient be tested was medical symptoms; frequent reasons for patients requesting the test were insurance purposes, being about to get married or having suspicions about a partner. A primary deterrent to physicians testing patients, even when patients requested it, was fear of traumatizing them. Fifty-six per cent of the physicians believed rapid tests would increase the number of HIV tests they performed; significant associations were found between this belief and whether physicians ever chose not to test patients they suspected were HIV-positive (a positive association) and whether they chose not to test specifically out of fear that patients would commit suicide (a negative association). Prior to any expansion of testing with rapid tests, training in counselling and confidentiality measures is essential, given that over half the medical personnel providing counselling to these physicians' patients had received no training in pre- and post-test HIV counselling.

Promoting quality of care for older people: developing positive attitudes to working with older people

AIMS

Managers and administrators have a key strategic role and responsibility for the way the care of older people is delivered within health and social care services, since the decisions made and directions taken at this level have a direct influence on services delivered. This article provides an outline of the context in which the services provided for older people have emerged, especially within health care, and offers strategies for the way forward.

BACKGROUND

The standard of care received by older people is high on the agenda in contemporary health care. Frequent reports have questioned this quality over the years, yet concerns still remain. A key factor influencing quality of care received by older people, can be attributed to the persistence and perpetuation of ageist attitudes held by society and those working within health and social care settings at all levels.

METHODS

Drawing upon a range of literature, an overview of those factors that seem to be attributable to the development of contemporary attitudes and perceptions about older people and their care are reviewed, focusing particularly upon health and social care workers, especially nurses.

FINDINGS

The role of education in particular is explored as this has a key role in influencing attitudes towards caring for older people and will impact directly on the way in which all care and services develop.

CONCLUSION

A number of areas are outlined for future development and research that aim to address and serve the needs of older people, and which could be supported at a managerial and administrative level to promote positive attitudes.

The family burden of injury interview: reliability and validity studies

OBJECTIVE

To assess the reliability and validity of a new instrument, the Family Burden of Injury Interview (FBII) was designed to assess the impact of childhood traumatic head injuries (THI) on the family.

PARTICIPANTS

99 Mothers of school-age children who experienced THI.

RESULTS

The FBII Total Score revealed group differences between families of children with severe THI and families of children with moderate THI. The measure also showed concurrent and predictive relationships to measures of the general impact of injury on families and maternal and child functioning.

CONCLUSION

The FBII is a promising tool for measuring the impact of injury-related stressors on the family.

The sleep of older people in hospital and nursing homes

Disturbed sleep can affect personal wellbeing and impede the rehabilitation and recovery of older people from illness. This paper reports the findings of a pilot study which included examination of sleep quality and sleep patterns of older people in community hospital and nursing home settings. A marked proportion of older people reported sleeping well in nursing care settings, and those in nursing homes slept better than those in the community hospital. The main causes of sleep disturbance in both settings were: needing to go to the toilet, noise, pain, and discomfort; a similar pattern was seen across the different settings. No discernible difference was found in quality of sleep and whether patients felt rested or not between those patients on hypnotic medication and those who were not. The implications of the findings for practice and future research are discussed.

Evaluation of gross and fine motor functions in children with hemidecortication: predictors of outcomes and timing of surgery

The purpose of this study is three-fold: First, to determine the levels of gross and fine motor functions in children before and after hemidecortication, using standardized measurement tools; second, to investigate if predictors of these outcomes can be characterized; and third, to explore if both clinical measures and functional magnetic resonance imaging (MRI) potentially can identify optimal timing of surgery. The Gross Motor Function Measure and the Quality of Upper Extremity Skills Test are shown to be comprehensive, standardized outcome measures of movement performance in affected children. Age at surgery and interval between age at seizure onset and age at surgery could be the most reliable predictors of clinical outcomes. Functional MRI studies are valuable in exploring the potential of the cortical reorganization that sustains residual sensorimotor function. The combination of clinical measures with functional MRI is a promising method of inquiry into developmental and plasticity processes.

Acute psychosocial impact of pediatric orthopedic trauma with and without accompanying brain injuries

BACKGROUND

The acute psychosocial effects of orthopedic injuries on children and their families are poorly understood. Previous studies have relied on retrospective reports or failed to take into account accompanying brain injuries. The purpose of the present study was to examine prospectively the psychosocial impact of pediatric orthopedic traumatic fractures with and without accompanying brain injuries.

METHODS

Participants were 108 children 6 to 12 years old with orthopedic injuries requiring hospitalization: group 1 (n=80) had fractures only, group 2 (n=28) also had moderate or severe brain injuries. Using standardized measures and parent interviews, we obtained preinjury estimates of family functioning and child behavior problems and postinjury measures of parental distress, family stresses, and child behavior.

RESULTS

Parents reported significant clinical distress (35% in group 1, 57% in group 2), family burdens (group 2 > group 1), and child behavioral changes (41% in group 1, 89% in group 2). Multiple regression analyses indicated that preinjury family status and brain injuries predicted postinjury parental and family distress.

CONCLUSION

Pediatric orthopedic injuries have greater social effects on children with accompanying brain injuries and poorer preinjury family functioning.

Effect of food processing on iron availability of African pearl millet weaning foods

The effects of different cereal precooking process (roasting and extrusion cooking) on iron availability and protein digestibility of four African weaning foods were investigated using in vitro methods. In two weaning foods based on pearl millet, cowpea and peanut, the cereal was extruded (A) or roasted (B). In two other weaning foods having a similar composition, a low proportion of milk powder was added and the cereal extruded (C) or roasted (D). The mean +/- SD iron values (mg/100 g) were: A, 5.56 +/- 0.18; B, 9.12 +/- 0.93; C, 5.89 +/- 0.23; D, 9.04 +/- 0.85. When the pearl millet was roasted, the iron content was higher than in the extruded weaning foods (P < 0.01). However, the percent of available iron of the roasted weaning foods was very low (B, 1.64 +/- 0.01; D, 0.91 +/- 0.02). The iron availability of the extruded weaning foods, A and C, was 3.5 times and 6.5 times higher than the corresponding roasted weaning foods, B and D, respectively. This represented 332.4 +/- 4.4 and 375.1 +/- 5.8 micrograms of available iron/100 g for A and C, respectively versus 149.5 +/- 0.9 and 82.2 +/- 1.8 micrograms of available iron/100 g for B and D, respectively. No significant differences in polyphenol contents were found according to the precooking process of the cereal. The extruded weaning foods showed a higher protein digestibility of approximately 10% than the roasted ones (P < 0.05). A positive correlation was found between in vitro iron availability and protein digestibility (r = 0.976, P < 0.02). Despite a high content of iron, the iron availability of roasted pearl millet weaning foods was quite low. Extrusion cooking of the cereal improved the protein digestibility and iron availability of pearl millet weaning foods; however, the amount of available iron remained insufficient to meet the iron requirements of infants whatever the cereal processing.

[Epidemiology of systemic inflammatory response syndrome, infection and septic shock in surgical intensive care patients]

This paper uses definitions of a consensus conference (ACCP/CCM) describing the epidemiology of SIRS, sepsis and septic shock in surgical ICU patients. During a period of 2 years a total of 656 patients were prospectively enrolled into the study. 335 patients (51.1% of the total population) developed SIRS (systemic inflammatory response syndrome); in 65 of these patients infection could be documented, i.e. they met the criteria of sepsis, 47 of these 65 septic patients developed septic shock, with mortality of 53.2%. SIRS is associated with a high sensitivity but a low specificity in predicting the outcome of ICU patients. Moreover, SIRS and sepsis appear to be of minor clinical relevance. On the contrary, septic shock describes a very high risk group of patients which should be characterized more closely in future studies.

Clinical use of three-dimensional video measurements of eye movements

Noninvasive measurements of three-dimensional eye position can be accurately achieved with video methods. A case study showing the potential clinical benefit of these enhanced measurements is presented along with some thoughts about technological advances, essential for clinical application, that are likely to occur in the next several years.

Clinical use of Three-Dimensional Video Measurements of Eye Movements

Noninvasive measurements of three-dimensional eye position can be accurately achieved with video methods. A case study showing the potential clinical benefit of these enhanced measurements is presented along with some thoughts about technological advances, essential for clinical application, that are likely to occur in the next several years. (Otolaryngol Head Neck Surg 1998;118:S35-S38)

Psychosocial characteristics of inner-city children with asthma: a description of the NCICAS psychosocial protocol. National Cooperative Inner-City Asthma Study

Previous research has demonstrated a significant reciprocal relationship between psychosocial factors and asthma morbidity in children. The National Cooperative Inner-City Asthma Study investigated both asthma-specific and non-specific psychosocial variables, including asthma knowledge beliefs and management behavior, caregiver and child adjustment, life stress, and social support. This article presents these psychosocial characteristics in 1,528 4-9-year-old asthmatic urban children and their caretakers. Caretakers demonstrated considerable asthma knowledge, averaging 84% correct responses on the Asthma Information Quiz. However, respondents provided less than one helpful response for each hypothetical problem situation involving asthma care, and most respondents had more than one undesirable response, indicating a potentially dangerous or maladaptive action. Both adults and children reported multiple caretakers responsible for asthma management (adult report: average 3.4, including the child); in addition, children rated their responsibility for self-care significantly higher than did adults. Scores on the Child Behavior Checklist indicated increased problems compared to normative samples (57.3 vs. 50, respectively), and 35% of children met the criteria for problems of clinical severity. On the Brief Symptom Inventory, adults reported elevated levels of psychological distress (56.02 vs norm of 50); 50% of caretakers had symptoms of clinical severity. Caretakers also experienced an average of 8.13 undesirable life events in the 12 months preceding the baseline interview. These findings suggest that limited asthma problem-solving skills, multiple asthma managers, child and adult adjustment problems, and high levels of life stress are significant concerns for this group and may place the inner-city children in this study population at increased risk for problems related to adherence to asthma management regimens and for asthma morbidity.

A One-Bead One-Peptide Combinatorial Library Method for B-Cell Epitope Mapping

The one-bead one-peptide combinatorial library method represents a powerful approach to the discovery of binding peptides for various macromolecular targets. It involves the synthesis of millions of peptides on beads such that each bead displays only one peptide entity. The peptide-beads that interact with a specific macromolecular target are then isolated for structure determination. We have applied this method to discovering peptide ligands for several murine monoclonal antibodies: (i) anti-beta-endorphin (continuous epitope), (ii) anti-vmos peptide, (iii) anti-human insulin (discontinuous epitope), and (iv) surface immunoglobulins (&mu;kappa) of two murine B-cell lymphoma cell lines (antigen unknown).

Assessing the effects of traumatic brain injury on family functioning: conceptual and methodological issues

Reviewed empirical literature published since 1975 on the effects of pediatric traumatic brain injury (TBI) on the family. Few systematic, hypothesis-driven investigations of the impact of TBI on family functioning have been conducted. However, existing findings indicate that severe TBI can adversely affect families and individual family members. Certain factors, such as poor preinjury functioning and parental psychological disorder, appear to place families at greater risk for long-term disruption. Issues associated with the conceptualization of the impact of TBI on various aspects of family functioning are discussed and methodological considerations are outlined. Special attention is given to novel strategies for studying these complex, multifaceted issues. Finally, a framework is proposed for examining the processes of family adaptation after pediatric TBI to guide future research directions.

Partnership in care: a critical review

In a comprehensive literature review, the author examines partnership in care between nurses and patients. The article describes the constraints on the relationship, assessing how theory relates to current practice and highlighting the stresses nurses are under as patient attitudes and expectations change.

Library of libraries: approach to synthetic combinatorial library design and screening of "pharmacophore" motifs

Construction of synthetic combinatorial libraries is described that allows for the generation of a library of motifs rather than a library of compounds. Peptide libraries based on this strategy were synthesized and screened with model targets streptavidin and anti-beta-endorphin antibody. The screens resulted in observation of expected motifs providing evidence of the effectiveness of the suggested approach.

Serum osteocalcin regulation in protein-energy malnourished children

To evaluate bone turnover changes occurring during protein-energy malnutrition, serum osteocalcin, a marker of bone formation, has been studied in healthy control, stunted, and severely malnourished (kwashiorkor and marasmus) Senegalese children. Serum osteocalcin levels were dramatically reduced in stunted, kwashiorkor, and marasmic children compared with control children. In addition serum osteocalcin levels of control children living in Senegal were lower (-46%) than those of African children living in France. Interestingly, serum osteocalcin level was not related to its major known regulators (1 alpha,25-dihydroxycholecalciferol, 25-hydroxycholecalciferol, and PTH) nor to stunting, but was related to serum transthyretin and thyroid hormones concentrations. These data suggest that serum osteocalcin level is related to protein-energy status and that bone formation was affected in apparently healthy and in malnourished Senegalese children. Serum osteocalcin could be a potent tool in the study of the alterations of bone formation in malnutrition.

Relationship of 24-hour urinary free cortisol to 4-hour salivary morning and afternoon cortisol and cortisone as measured by a time-integrated oral diffusion sink

The relationship between salivary corticosteroids integrated over 4-hour periods and urinary free cortisol collected over 24 hours was investigated in normal controls. Twenty-one normal volunteers wore "oral diffusion sink" sampling devices in their mouths for two 4-hour periods (08:00-12:00 hours and 13:00-17:00 hours) and on the same day collected a 24-hour urine specimen. Time-integrated salivary corticosteroid concentrations were determined from the sample devices and urinary free cortisol was measured. Salivary corticosteroids were not consistently higher in the morning than in the afternoon period and did not differ between men and women. Urinary free cortisol levels were higher in women. No salivary corticosteroids measure was significantly correlated with urinary free cortisol. We conclude that time-integrated salivary corticosteroids do not reflect urinary free cortisol levels in normal controls.

Application of a dual color detection scheme in the screening of a random combinatorial peptide library

Selectide Technology is a random synthetic combinatorial library method in which millions of random compounds are screened in parallel for their ability to bind to a tagged macromolecular target. The library consists of millions of beads and each individual bead expresses a unique chemical compound such as a peptide. In the standard enzyme-linked colorimetric detection scheme, the positive bead which turns color is isolated for microsequencing. In this paper, a dual color detection scheme using two sequential orthogonal probes is described. This dual color system enables one to rapidly differentiate false positive beads from true positive beads, resulting in a much more efficient use of the microsequencer.

Gentamicin vestibulotoxicity

We reviewed 36 patients with gentamicin vestibulotoxicity to determine its relationship to gentamicin dosage, serum gentamicin levels, and the development of gentamicin nephrotoxicity. Thirty of the patients had received intravenous or intramuscular gentamicin; six had received intraperitoneal gentamicin. Sixteen of the 30 patients treated with intramuscular or intravenous gentamicin had received less than the recommended maximum dose of 5 mg/kg/day for less than the recommended maximum period of 10 days. Nephrotoxicity as well as vestibulotoxicity developed in 16 of these 30 patients. Gentamicin vestibulotoxicity was not recognized before discharge from hospital in 32 of the 36 patients. We conclude that as far as the vestibular system is concerned there is no safe gentamicin dose and no safe serum gentamicin level, and there is an increased risk of vestibulotoxicity in patients in whom nephrotoxicity develops. Physicians who use gentamicin should become more aware of the clinical features of vestibulotoxicity because stopping gentamicin as soon as symptoms of vestibulotoxicity appear could prevent permanent impairment of vestibular function.

Synthesis of combinatorial libraries with only one representation of each structure

A technique of generating libraries in which every compound is displayed only once and all possible combinations are prepared with absolute certainty is presented. The method is based on the stepwise division of a continuous carrier in each step of randomization. Polypropylene membrane and cotton thread were evaluated as potential supports for this approach to library construction. Cotton thread accommodates 400 nmol of test compound per cm, but its mechanical properties limit the dimension of libraries. An alternative combinatorial library of "restructurable toothbrushes" is suggested.

Association of IBM's "A Plan for Life" health promotion program with changes in employees' health risk status

To evaluate the association of participation in IBM's "A Plan for Life" program with changes in blood pressure, serum total, high-density lipoprotein, and non-high-density lipoprotein cholesterol, body mass index, and cigarette smoking, we compared changes in these measures over a 1- to 5-year period among program participants and nonparticipants initially found to be at risk. After adjustment for age, sex, time to follow-up, and baseline values, the proportion of participants no longer at high risk was significantly greater than the corresponding proportion of nonparticipants in the areas of blood pressure total and non-high-density lipoprotein cholesterol and smoking cessation.

Growth hormone and insulin-like growth factor I in athletes performing a marathon at 4000 m of altitude

Human growth hormone (hGH) characteristically increases during physical exercise. In sports medicine, hGH changes have mostly been described in short-term performances under standardized laboratory procedures. We studied hGH and insulin-like growth factor I (IGF-I) under field conditions in 7 runners performing a marathon at 4000 m of altitude, to study the hormonal changes under extreme endurance effort and to evaluate the release of 22 kDa and 20 kDa monomers under these conditions, in comparison with a control group. The blood samples were taken at sea level, after 1 week of acclimatization, immediately after the run, and after a recovery of 24 h from the marathon. hGH was quantified by using a polyclonal method, a 22 kDa specific monoclonal method and a monoclonal method recognizing both 22 kDa and 20 kDa isoforms. A significant increase in hGH was noted using all methods after the marathon, followed by a significant decrease after recovery. Significant differences between athletes and controls were found only for the measurement after the marathon. No statistically reliable decrease of IGF-I was observed in athletes and controls. We obtained more limited hGH rises than previously described in athletes; the importance of lactate levels indicates that the use of physical exercise as a stimulation test for hGH should be closely standardized. The 20 kDa monomer and other hGH molecular forms played a limited role in the hormone increase: in our experience, elevation of hGH in heavy exercise corresponds mostly to the 22 kDa isoform. We suggest that the evaluation of hGH elevation in sports medicine could be accurately performed using specific 22 kDa monoclonal assays.

Discovery of D-amino-acid-containing ligands with selectide technology

When all L-amino acid (aa) random peptide libraries synthesized on solid-phase particles were screened (Selectide Technology), we identified several peptide ligands (YG_F_) that interacted specifically with an anti-beta-endorphin monoclonal antibody (clone 3E7) (single-letter aa symbols; symbols '_' indicate variable aa). Here, we report on the screening of three different D-aa-containing pentapeptide libraries (XxXxX, xXxXx and xxxxx, wherein X = L-aa, and x = D-aa) with the same antibody, in which several D-aa-containing ligands were identified. The binding affinities of many of these D-aa-containing ligands were as least two orders of magnitude lower than that of YGGFL, for which the Ki is 17.5 nM.

Discovery of biologically active peptides in random libraries: solution-phase testing after staged orthogonal release from resin beads

To speed drug discovery, we developed an approach for identification of individual peptides with a desired biological activity from a library containing millions of peptides. The approach uses sequential orthogonal release of chemically synthesized peptides from insoluble beads, followed by testing in solution. In this system, each bead within a library of beads has one peptide sequence, but peptide molecules are attached to the bead with three types of chemical linkers, including two linkers cleavable at different pH optima. An uncleavable linker keeps some peptide attached to the bead for sequencing positives from the solution assay. Applicability of this discovery technique was documented by identifying ligands for a monoclonal antibody and for the human platelet fibrinogen receptor, glycoprotein IIb/IIIa.

Endocrine correlates of stress vulnerability

Psychological stress is implicated as one element in a constellation of risk factors for the development and maintenance of psychosomatic disease. Endocrine responses to stressful experience vary widely among individuals, and may account for some of the individual variability in vulnerability to development of psychosomatic symptoms under stress. Endocrine stress responsiveness probably has a large genetic component, but is also known to be modifiable by prolonged and/or profound stressful experience. Social and cognitive factors influence the pituitary-adrenal response to stress, and sex differences may also be significant. It may be possible to develop specific tests of endocrine responsiveness, perhaps incorporating psychological and pharmacological challenges, that may serve as markers of chronic stress experience or of vulnerability to psychosomatic disorders.

Cognitive-behavioral treatment of health-impairing food phobias in children

Three cases reports describe assessment and treatment of three boys (ages 6 to 8 years) hospitalized because of weight loss and malnutrition, caused by severe dietary restriction and/or refusal to eat solid food. Psychological, behavioral, and medical assessments indicated that the boys were of average intelligence, without other significant psychological or medical disorders. Their eating disturbances were conceptualized as phobic disorders maintained by family factors reinforcing the children's avoidant behaviors. Cognitive-behavioral treatment consisted of an individualized combination of contingency management, shaping, desensitization, relaxation training, education, and cognitive restructuring. Generalization and maintenance were promoted by training parents to implement treatment at home before discharge. Treatment positively affected overall caloric intake, weight gain, number of solid foods accepted, and incidence of emesis.

Failure of tryptophan deficiency to reduce specifically serum levels of transthyretin or albumin in rats

Because transthyretin (TTR) is a tryptophan-rich molecule and a sensitive nutritional marker, tryptophan deficiency might markedly influence the circulating level of TTR. The effect of severe tryptophan (Trp) deficiency on serum TTR, as well as on albumin and transferrin levels, was studied in growing rats for 8 d. The animals were then refed a control diet for 12 d. The Trp-deficient and control diets contained 0.008 and 0.34% Trp, respectively. A loss of body weight and a dramatic reduction in food intake were observed in the Trp-deficient rats. Although serum total Trp concentration was significantly less in these rats than in pair-fed controls, serum TTR declined to the same extent in both groups compared to control rats fed ad libitum. Albumin concentrations were not altered, but transferrin levels declined slightly in the Trp-deficient rats compared to both the pair-fed group and the controls fed ad libitum. Refeeding the control diet to Trp-deficient rats restored total and free Trp concentrations, as well as TTR and transferrin levels, but body weight and food intake remained lower than in the control group. To examine the effect of moderate Trp restriction, rats were fed for 2 wk a diet whose Trp content was 50% less than that of the control diet. Although total and free Trp concentrations were significantly lower in the rats fed the Trp-deficient diet than in the control group, body weight, food intake and TTR levels were similar in both groups. The results suggest that acute and severe Trp deficiency per se does not modify TTR and albumin levels.

Genetic control of murine T cell proliferative responses to Mycobacterium leprae. V. Evidence for cross-reactivity between host antigens and Mycobacterium leprae

T cell proliferative responses to Mycobacterium leprae were measured by immunization of mice at the base of the tail with Ag and challenging lymphocytes from draining lymph nodes in culture with M. leprae. C57BL/10J and B10.BR mice were identified as low responder mice and the congenic strains B10.M, B10.Q, and B10.AKM as high responders whereas F1 (high x low) hybrid mice were found to be low responders. The cellular basis of low responsiveness did not appear to result from a defect in Ag-presenting cells or the activation of suppressor T cells by M. leprae. The influence of the environment in which T cells developed on responsiveness to M. leprae was analyzed in chimeric mice prepared by irradiating F1(C57BL/10J x B10.M) mice and reconstituting with bone marrow from C57BL/10J, B10.M, or F1 donors. Six weeks later, chimeric mice were immunized with M. leprae, lymph node cells were subsequently prepared, and H-2 phenotyped and challenged in culture with M. leprae Ag. T cell proliferative responses were found to be low in all cases, similar to those observed using lymph node cells from F1 hybrid mice. These results suggested that high responder B10.M lymphocytes developing in the irradiated F1 mice became tolerized to antigenic determinants found on M. leprae. This implied cross-reactive epitopes existed between some mouse strains and M. leprae. Low responsiveness to M. leprae in low responder and F1 hybrid mice may result from tolerance to H-2-encoded Ag that show cross-reactivity with M. leprae.

Genetic control of murine T cell proliferative responses to Mycobacterium leprae. V. Evidence for cross-reactivity between host antigens and Mycobacterium leprae

T cell proliferative responses to Mycobacterium leprae were measured by immunization of mice at the base of the tail with Ag and challenging lymphocytes from draining lymph nodes in culture with M. leprae. C57BL/10J and B10.BR mice were identified as low responder mice and the congenic strains B10.M, B10.Q, and B10.AKM as high responders whereas F1 (high x low) hybrid mice were found to be low responders. The cellular basis of low responsiveness did not appear to result from a defect in Ag-presenting cells or the activation of suppressor T cells by M. leprae. The influence of the environment in which T cells developed on responsiveness to M. leprae was analyzed in chimeric mice prepared by irradiating F1(C57BL/10J x B10.M) mice and reconstituting with bone marrow from C57BL/10J, B10.M, or F1 donors. Six weeks later, chimeric mice were immunized with M. leprae, lymph node cells were subsequently prepared, and H-2 phenotyped and challenged in culture with M. leprae Ag. T cell proliferative responses were found to be low in all cases, similar to those observed using lymph node cells from F1 hybrid mice. These results suggested that high responder B10.M lymphocytes developing in the irradiated F1 mice became tolerized to antigenic determinants found on M. leprae. This implied cross-reactive epitopes existed between some mouse strains and M. leprae. Low responsiveness to M. leprae in low responder and F1 hybrid mice may result from tolerance to H-2-encoded Ag that show cross-reactivity with M. leprae.