Effect of fried sunflower oil intake on mandibular biomechanical competence of growing rats

Previous studies by us demonstrated that the consumption of thermally oxidized oil diet adversely affects body growth, lipid metabolism, bone mass and femur biomechanical competence.

AIM

The aim of this study was to evaluate the effects of a diet containing fried sunflower oil on the mandible of growing rats.

MATERIALS AND METHOD

Male Wistar rats (21±1 day old) (n=21) were assigned at weaning to one of three diets for 8 weeks: a control diet (C), a diet containing sunflower oil (SFO) or a diet containing sunflower oil that had been repeatedly heated (SFOx); both SFO and SFOx were mixed with commercial rat chow at 13% (w/w). The consistency and viscosity of the 3 diets were similar. Zoometrics and food intake were recorded weekly. At wk=8, mandibular growth was assessed by measurements of anatomical points of cleaned bones, and mandible biomechanical competence was assessed to estimate the structural properties of the bone. Statistical analysis was performed by SPSS v. 20.0.

RESULTS

Rats fed SFOx diet attained the lowest final body weight (P=0.0074), mandibular weight (P=0.0001) and mandibular \length (P=0.0002). Load bearing capacity (Wf;N), load of yielding (Wy;N) and stiffness (Wy/dy;N/mm) of the mandible were negatively affected by both sunflower oil diets (fresh and fried) (P=0.001; P=0.002; P=0.003, respectively) though SFOx induced the most significant reduction in Wy/dy (C:44.4(5.4) > SFO:36.1(2.1) > SFOx: 26.3(3.7) N/ mm; P=0.003). The deleterious effect of SFOx on mandibular growth was more accentuated on the posterior part of the bone (C:11.4(0.3)=SFO:11.2(0.2)>SFOx: 10.7(0.2) mm; p=0.0005); the anterior/ posterior ratio (C:1.25(0.02)=SFO:1.27(0.02)

CONCLUSION

Consumption of SFOx diet during growth could affect mandibular morphometric properties and biomechanical competence, in terms of bone stiffness.

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Key Words

• biomechanical competence
• fried sunflower oil
• growth
• healthy rats
• mandibular morphometrics

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MESH Headings

• Rats
• Animals
• Male
• Sunflower Oil
• Rats, Wistar
• Diet
• Mandible

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Grants

• UBACyT 20020170100138BA, 2018-2023 Buenos Aires University

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Cognitive impairment related to arterial stiffness in cardiovascular disease patients with severe periodontitis

Severe periodontal disease (SPD) associated with systemic peripheral inflammation, cognitive impairment (CI) and arterial stiffness (AS) has been recognized. The aim of this study was to investigate whether CI and arterial stiffness (AS) occur in cardiovascular disease (CVD) patients with SPD. A crosssectional case-control study included hospitalized patients with CVD. Demographic characteristics, CVD and atherogenic risk factors were recorded. SPD was diagnosed by clinical and radiographic dental examinations. Dental clinical attachment level (CAL) and CAL % were recorded. A Mini-Mental State Examination test (MMSE) assessed cognition, a MMSE score of < 27 was set as the cut-off point of CI; a score ≥ 27 was considered as no CI. Patients were categorized into: MMSE<27 (cases) and MMSE≥27 (controls). AS was evaluated by pulse wave velocity (PWV). Serum VCAM-1 levels were determined in a random sample. Results: This study comprised 91 patients (cases, n=26; 29.6%; controls, n=65, 71.4%); aged 73±8 vs. 73±7 years, respectively (p=0.73), of whom 53.8% and 36.9% respectively, were women; SPD was found to be a risk factor for CI; the presence of SPD increased the risk for MMSE <27 by an average 5.39 times (model 1). PWV was associated with MMSE < 27 in the three models. The risk of having MMSE < 27 increased an average of 2.404-fold for each 1-unit increase in PWV. SPD and AS had significant and independent associations on the risk for development CI. MMSE negatively correlated with CAL% (r=0.69) and PWV (r=0.70). PWV positively correlated with CAL% (r=0.67). Serum VCAM-1 levels were higher in SPD with lower MMSE scores. In conclusion, SPD increases the risk of development of cognitive decline in CVD patients. PWV was directly associated with the risk of cognitive decline. These findings denote a significant opportunity to improve periodontal health in order to avert CI in CVD patients.

Oxidative stress response to air particle pollution in a rat nutritional growth retardation model

Air pollution consisting of gases and particulate matter-(PM) represents a health problem in cities worldwide. However, air pollution does not impact equally all individuals, as children appear to be more vulnerable subpopulations. Air pollution and malnutrition are two distinct factors that have been associated with oxidative damage. Therefore, the interaction between environmental exposure and nutritional status in populations at risk needs to be explored. The aim of this study was to examine oxidative metabolism in lung, heart and liver in malnourished young rats exposed to residual oil fly ash (ROFA). A Nutritional Growth Retardation (NGR) model was developed in weanling male rats placed on a 20% restricted balanced diet for 4 weeks. Then, NGR and control rats were intranasally instilled with either ROFA (1mg/kg BW) or phosphate buffered saline (PBS). Twenty-four hr post-exposure lung, heart and liver were excised, and serum collected. ROFA induced lung and liver inflammation in control and NGR animals as evidenced by lung polymorphonuclear neutrophil (PMN) recruitment and alveolar space reduction accompanied by liver lymphocyte and binucleated hepatocyte level increase. In lung and liver, antioxidant defense mechanisms reduced lipoperoxidation. In contrast, only in NGR animals did ROFA exposure alter heart oxidative metabolism leading to lipid peroxidation. Although histological and biochemical tissue alterations were detected, no marked changes in serum liver and heart systemic biomarkers were observed. In conclusion, NGR animals responded differently to PM exposure than controls suggesting that nutritional status plays a key role in responsiveness to ambient air contaminants.

Efficacy of phytosterols and fish-oil supplemented high-oleic-sunflower oil rich diets in hypercholesterolemic growing rats

Phytosterols (P) and fish-oil (F) efficacy on high-oleic-sunflower oil (HOSO) diets were assessed in hypercholesterolemic growing rats. Controls (C) received a standard diet for 8 weeks; experimental rats were fed an atherogenic diet (AT) for 3 weeks, thereafter were divided into four groups fed for 5 weeks a monounsaturated fatty acid diet (MUFA) containing either: extra virgin olive oil (OO), HOSO or HOSO supplemented with P or F. The diets did not alter body weight or growth. HOSO-P and HOSO-F rats showed reduced total cholesterol (T-chol), non-high-density lipoprotein-cholesterol (non-HDL-chol) and triglycerides and increased HDL-chol levels, comparably to the OO rats. Total body fat (%) was similar among all rats; but HOSO-F showed the lowest intestinal, epididymal and perirenal fat. However, bone mineral content and density, and bone yield stress and modulus of elasticity were unchanged. Growing hypercholesterolemic rats fed HOSO with P or F improved serum lipids and fat distribution, but did not influence material bone quality.

Monounsaturated fatty acids-rich diets in hypercholesterolemic-growing rats

The effects of replacing dietary saturated fat by different monounsaturated fatty acid (ω-9MUFA) sources on serum lipids, body fat and bone in growing hypercholesterolemic rats were studied. Rats received one of the six different diets: AIN-93G (control, C); extra virgin olive oil (OO) + C; high-oleic sunflower oil (HOSO) + C or atherogenic diet (AT) for 8 weeks; the remaining two groups received AT for 3 weeks and then, the saturated fat was replaced by an oil mixture of soybean oil added with OO or HOSO for 5 weeks. Rats consuming MUFA-rich diets showed the highest body fat, hepatic index and epididymal, intestinal and perirenal fat, and triglycerides. T-chol and non-HDL-chol were increased in HOSO rats but decreased in OO rats. Bone mineral content and density were higher in both OO and HOSO groups than in AT rats. This study casts caution to the generalization of the benefits of MUFA for the treatment of hypercholesterolemia.

Prevalence of dyslipidemia and metabolic syndrome risk factor in overweight and obese children

OBJECTIVE

To study the prevalence of dyslipidemia and metabolic syndrome risk factors in overweight/ obese children and adolescents.

METHODOLOGY

The study included 139 healthy white Argentinean children/adolescents (aged 8-14 years) who were overweight (n = 30) or obese (n = 109), based on BMI z score according to WHO, 2007. Children were referred to the Nutrition Clinic, San Martin University Hospital, Buenos Aires, Argentina for evaluation and treatment. Dyslipidemia was considered when one or more serum lipids (mg/dL) were out of range: total cholesterol ≥ 200, high-density lipoprotein (HDL-C) ≤ 40, triglycerides (TG) > 110, low-density lipoprotein (LDL-C) > 130 or non-HDL-C > 145 and fasting blood glucose (FBG) > 110. Additional metabolic syndrome risk factors included: increased waist circumference (WC, ≥ 90th percentile) and high blood pressure (> 90th percentile). A history of low birth weight (< 2.5 kg) and a family history of: dyslipidemia (FHDL), premature acute myocardial infarction (FHPAMI) and/or type 2 diabetes mellitus (FHT2DM) were also assessed.

RESULTS

The prevalence of dyslipidemia among overweight and obese children was 50.4% and its pattern was: hypertriglyceridemia 31.9%, low HDL-C 29.7%, high non-HDL-C 15.8%, hypercholesterolemia 11.9%, and elevated LDL-C 10.7%. The dyslipidemia was more often detected among those with increased WC (55.4%), FHDL (51.1%), and FHT2DM (48%); prevalence was lower in those with FHPAMI (18.7%) and low birth weight (4.3%). Most children presented a variety of metabolic syndrome risk factors; only 25.8% did not have any such alterations identified. BMI z score showed a positive association with TG and negative with HDL-C. Overweight and obesity increased the odds ratios of metabolic syndrome risk factors, hypertriglyceridemia and low HDL-C.

CONCLUSIONS

Overweight/obese children were prone to have dyslipidemia and metabolic syndrome. Excess body weight is an important harbinger of health that requires the assessment of multiple parameters to discern further health concerns that may be amenable to specific treatment.

Low protein intake magnifies detrimental effects of ovariectomy and vitamin D on bone

Protein-induced changes in bone and calcium homeostasis could potentially be greater in the elderly and in women at risk for osteoporosis. We hypothesize that a low protein intake would magnify the negative changes in bone metabolism seen in vitamin D (vitD) insufficiency and/or estrogen deficiency. The present study was undertaken to better understand how a low protein diet along with vitD insufficiency could affect bone metabolism using a rodent ovariectomized (OVX) model. Rats (n = 60) underwent ovariectomy (OVX) or sham operation. The first 15 days after surgery, all rats were fed a standard rodent diet. Thereafter, rats (n = 10/group) were fed a low protein diet (LP; 2.5 %) or a control diet (NP; 12.5 %) with 100 IU% vitD (+D; cholecalciferol) or without vitD (-D) for 45 days. The groups were as follows: SHAM + NP + D (control); SHAM + LP + D; SHAM + LP - D; OVX + NP + D; OVX + LP + D; OVX + LP - D. Body weight (BW) of control and OVX + NP + D groups increased while those feeding the LP diet, independently of vitD feedings, decreased (p < 0.05). The OVX + LP - D group presented the lowest serum Ca, phosphorus and osteocalcin levels and the highest CTX levels (p < 0.05). At the end of the study, total skeleton bone mineral content, proximal tibia bone mineral density, bone volume and trabecular number levels decreased as follows: SHAM + NP + D (controls) > SHAM + LP + D > OVX + NP + D > SHAM + LP - D > OVX + LP + D > OVX + LP - D (p < 0.05). A low protein diet negatively affected bone mass and magnified the detrimental effects of vitD and/or estrogen deficiencies.

Oxidative stress assessed in saliva from patients with acute myocardial infarction. A preliminary study

There is evidence that acute myocardial infarction (AMI) is associated with increasing production of reactive oxygen species and tissue injury. The aim of this study was to assess the presence of oxidative stress indices in saliva 24 and 48h after AMI.

MATERIALS AND METHODS

We designed a prospective study comparing salivary levels of biomarkers of oxidative stress in patients with AMI with elevation of the ST segment in electrocardiogram versus clinically healthy subjects. Oxidative stress indices including the rate of oxidation of 2'7' dichlorohydrofluorescein diacetate (DCFH-DA) and the activity of the antioxidant enzyme catalase (CAT) were evaluated in saliva from patients with AMI at 24 and 48 hours. At each sampling time, blood was drawn for serum markers of myocardial infarction.

RESULTS

This study included ten patients with acute ST-segment elevation myocardial infarction and ten clinically healthy controls. Mean age was 67.8 +/- 11.1 vs. 48.7 +/- 4.1 years (p < 0.001) and gender was 60% male vs. 50% (p > 0.05) for AMI vs. controls, respectively. Our results demonstrated an increase in the rate of oxidation of DCFH-DA in the myocardial infarction group as compared with controls (p = 0.004), which remained unchanged at 48h. There was no difference in salivary catalase activity between controls and AML subjects at 24h or at 48h post-diagnosis (p = 0.157). The relationship between CAT48 and DCFH-DA48 was fairly significant (r = 0.39; p = 0.053).

CONCLUSION

This preliminary study showed that biomarkers of oxidative stress are detectable in saliva of patients with acute myocardial infarction.

CLINICAL RELEVANCE

Future studies using a larger population are needed to confirm these observations and to explore the possibility of using the saliva to monitor evolving diagnosis and prognosis in acute coronary syndrome.

High-fat diets affect energy and bone metabolism in growing rats

BACKGROUND

High-fat diets are usually associated with greater weight (W) gain and body fat (BF). However, it is still unclear whether the type and amount of fat consumed influence BF. Additionally, dietary fat intake may also have consequences on skeletal health.

OBJECTIVE

To evaluate in healthy growing rats the effects of high-fat diets and type of dietary fat intake (saturated or vegetable oils) on energy and bone metabolism.

METHODS

At weaning, male Wistar rats (n = 50) were fed either a control diet (C; fat = 7% w/w) or a high-fat diet (20% w/w) containing either: soybean oil, corn oil (CO), linseed oil (LO), or beef tallow (BT) for 8 weeks. Zoometric parameters, BF, food intake and digestibility, and total and bone alkaline phosphatase (b-AP) were assessed. Total skeleton bone mineral density (BMD) and content (BMC), BMC/W, spine BMD, and bone volume (static-histomorphometry) were measured.

RESULTS

Animals fed BT diet achieved lower W versus C. Rats fed high-fat vegetable oil diets showed similar effects on the zoometric parameters but differed in BF. BT showed the lowest lipid digestibility and BMC. In contrast, high vegetable oil diets produced no significant differences in BMC, BMC/W, BMD, spine BMD, and bone volume. Marked differences were observed for LO and BT groups in b-AP and CO and BT groups in bone volume.

CONCLUSION

BT diet rich in saturated fatty acids had decreased digestibility and adversely affected energy and bone metabolisms, in growing healthy male rats. There were no changes in zoometric and bone parameters among rats fed high vegetable oil diets.

Co-managed care for fragility hip fractures (Rochester model)

Hip fractures in older adults are a common event with a high risk of morbidity and mortality. Patients who sustain a hip fracture often present with multiple co-morbid conditions that can benefit from co-management by orthopedic surgeons and geriatricians. This manuscript describes a co-managed model of care for patients with hip fractures. This model of care will be explained, and the benefits and results will be described. Retrospective review of the care of all native non-pathological hip fracture patients aged 60 years and older admitted between April 2005 and March 2009 to a 261-bed community teaching hospital. The outcome measures include patient characteristics, length of stay, mortality, 30-day readmission, re-operation, and costs of care. Seven hundred fifty-eight patients were identified with an average age of 84.8 (SD 8.4); 77.8% of the patients were female, 94.7% Caucasian, and 37.3% from nursing homes, and the mean Charlson score is 2.9 (SD 2.1). The length of stay was 4.3 days, 30-day readmission rate was 10.4%, 17-month re-operation rate was 1.9%, and costs of care to the system were $15,188. The 1-year mortality rate was 21.2%. This model of care resulted in improvements in all measures studied. Previous studies have shown reduction in in-hospital complications. Additional studies are needed to show if this model of care can be translated to other systems or to other surgical conditions. Wide application of this model care could substantially improve the quality of care and cost of caring for frail elders with hip fractures.

Ortho-geriatric service--a literature review comparing different models

In the fast-growing geriatric population, we are confronted with both osteoporosis, which makes fixation of fractures more and more challenging, and several comorbidities, which are most likely to cause postoperative complications. Several models of shared care for these patients are described, and the goal of our systematic literature research was to point out the differences of the individual models. A systematic electronic database search was performed, identifying articles that evaluate in a multidisciplinary approach the elderly hip fracture patients, including at least a geriatrician and an orthopedic surgeon focused on in-hospital treatment. The different investigations were categorized into four groups defined by the type of intervention. The main outcome parameters were pooled across the studies and weighted by sample size. Out of 656 potentially relevant citations, 21 could be extracted and categorized into four groups. Regarding the main outcome parameters, the group with integrated care could show the lowest in-hospital mortality rate (1.14%), the lowest length of stay (7.39 days), and the lowest mean time to surgery (1.43 days). No clear statement could be found for the medical complication rates and the activities of daily living due to their inhomogeneity when comparing the models. The review of these investigations cannot tell us the best model, but there is a trend toward more recent models using an integrated approach. Integrated care summarizes all the positive features reported in the various investigations like integration of a Geriatrician in the trauma unit, having a multidisciplinary team, prioritizing the geriatric fracture patients, and developing guidelines for the patients' treatment. Each hospital implementing a special model for geriatric hip fracture patients should collect detailed data about the patients, process of care, and outcomes to be able to participate in audit processes and avoid peerlessness.

Indoleamine 2,3-dioxygenase, an emerging target for anti-cancer therapy

The inability of the host immune system to control tumor growth appears to result from dominant mechanisms of immune suppression that prevent the immune system from effectively responding in a way that consistently results in tumor rejection. Among the many possible mediators of tumoral immune escape, the immunoregulatory enzyme, indoleamine 2,3-dioxygenase (IDO), has recently gained considerable attention. IDO is a heme-containing, monomeric oxidoreductase that catalyzes the first and rate-limiting step in the degradation of the essential amino acid tryptophan to N formyl-kynurenine. Tryptophan depletion as well as the accumulation of its metabolites results in a strongly inhibitory effect on the development of immune responses by blocking T cell activation, inducing T cell apoptosis and promoting the differentiation of naïve T cells into cells with a regulatory phenotype (T(regs)). Recent data obtained from preclinical tumor models demonstrate that IDO inhibition can significantly enhance the antitumor activity of various chemotherapeutic and immunotherapeutic agents. These results, coupled with data showing that increased IDO expression is an independent prognostic variable for reduced overall survival in cancer patients, suggest that IDO inhibition may represent an effective strategy to treat malignancies, either alone or in combination with chemotherapeutics or other immune based therapies. This review will focus on the role of IDO as a mediator of peripheral immune tolerance, evidence that IDO becomes dysregulated in human cancers, and the latest progress on the development of IDO inhibitors as a novel anti-cancer therapy.

The use of ozone to lighten teeth. An experimental study

Tooth-whitening agents are available for therapeutic use in the dental office or at home. However, whitening more severe stains, such as those caused by systemic ingestion of tetracycline, constitutes a challenge. The aim of this study was to evaluate, in an experimental model of growing rats, the efficacy of using ozone to lighten tetracycline-stained incisors. At weaning, male Wistar rats (n=40) were randomly assigned to one of three groups. Two control groups, C2, and C60 (n=8, each) were used to document the usual age-related color. The third group (n=24) received 0.25 g% of oxytetracycline (0) until 60 days of age. These rats were subsequently divided into three further groups: O0, O3 and O5 (n=8, each). These rats were anesthetized; O3 and O5 groups received ozone application to the lower incisors for 3 (group O3) or 5 minutes (group O5), respectively; while O0 did not receive the ozone treatment. Teeth were then photographed and the incisors from the control (C60) and treatment groups (O0, O3 and O5) were cut, and compared to a standard color guide (there were eight shades numbered 0 to 7, lightest to darkest) to assess the hue visually. The teeth were then placed in phosphoric acid to quantify the color by spectrophotometry. The data (mean +/- SD) were analyzed by One-Way Analysis of Variance (ANOVA) followed by Tukey's test or Dunnett test. The visual observation, analyzed blindly by one investigator showed that O3 and O5 groups had diminished yellowing of the teeth as compared to the untreated O0 group (P < 0.001). The color quantified by spectrophotometry also detected significant differences among groups (O3 < O0, P < 0.01; O5 < O0, P < 0.001 and O5 < 03, P < 0.01). C21 and C60 were significantly different among groups (P < 0.001). This is the first experimental study to show that ozone can be successfully used for lightening the yellowish tinge of tetracycline-stained rat incisors. Further studies are required for its potential use in the dental clinic.

[Body composition by simple anthropometry, bioimpedance and DXA in preschool children: interrelationships among methods]

OBJECTIVE

To examine the interrelationships of body composition variables derived from simple anthropometry, bioelectrical impedance (BIA) and dualenergy X-ray absorptiometry (DXA).

POPULATION, MATERIAL AND METHODS

A total of 230 healthy preschool children (118 males and 112 females) age 4-6 years, attending a day care center, were examined to determine body mass index (BMI) and waist circumference (WC). Percentage of body fat content (%BF) was predicted by BIA (Maltron BF- 900) and DXA (Lunar DPX-L, pediatric software).

RESULTS

BMI and WC did not show significant differences among sex, while %BF by BIA or DXA did. BIA measures were lower than DXA s (p <0.0001). Correlation between BIA vs. anthropometric methods and WC vs. DXA were moderate (Pearson r= 0.43 to 0.53), whereas the other correlations were strong (r= 0.71 to 0.83). However Bland Altman comparison showed wide limits of agreement between BIA and DXA; BIA significantly underestimated %BF as determined by DXA (p <0.0001).

CONCLUSION

The methods used to estimate body composition in healthy preschool children highly correlated. However, the Bland Altman procedure suggests that BIA and DXA should not be used interchangeably.

Vitamin D insufficiency reduces the protective effect of bisphosphonate on ovariectomy-induced bone loss in rats

The present study was carried out to obtain an experimental model of vitamin D (vit D) insufficiency and established osteopenia (experiment 1) to then investigate whether vit D status, i.e. normal or insufficient, interferes with bone mass recovery resulting from bisphosphonate therapy (experiment 2). Rats (n = 40) underwent OVX (n = 32) or a sham operation (n = 8). The first 15 days post-surgery, all groups were kept under fluorescent tube lighting and fed a diet containing 200 IU% vit D (+D). They were then assigned during an additional 45 days to receive either +D or a diet lacking vit D (-D) and kept under 12 h light/dark cycles using fluorescent or red lighting. Serum 25HOD was significantly lower in -D rats (P < 0.0001). The type of lighting did not induce differences in 25OHD, calcium (sCa), phosphorus (sP), bone alkaline phosphatase (b-AL), CTX, bone density or histology. No osteoid was observed in undecalcified bone sections. Experiment 2 (105 days): rats were fed either +D or -D according to experiment 1 and were treated with either placebo or 16 mug olpadronate (OPD)/100 g rat/week during the last 45 days. Whereas 25HOD was significantly lower (P < 0.0001) in -D/OPD than in +D/OPD rats, no significant differences in sCa, sP, b-AL or CTX were observed. OPD prevented the loss of lumbar spine (LS) and proximal tibia (PT) BMD and the decrease in bone volume (BV/TV) (P < 0.05) and in the number of trabeculae observed in untreated rats. However, +D/OPD animals presented significantly higher values of LS BMD, PT BMD and BV/TV than -D/OPD rats (P < 0.05). No osteoid was observed in undecalcified sections of bone. In summary, this is the first experimental study to provide evidence that differences in vit D status may affect the anticatabolic response to bisphosphonate treatment. However, the molecular mechanism through which vit D insufficiency reduces the effect of the aminobisphosphonate remains to be defined.

Metabolic status in growing rats fed isocaloric diets with increased carbohydrate-to-fat ratio

OBJECTIVE

A low-fat diet is hypothesized to be associated with significant weight loss. However, most previous studies have been limited to low-fat, low-calorie restrictive diets. This study evaluated the effect of isocaloric diets given "ad libitum" but different in relative amounts of fat and carbohydrate on body size, energy metabolism, body composition, insulin-like growth factor-1, and leptin serum levels in growing Wistar rats.

METHODS

Weanling male rats were fed with one of three diets that contained a ratio of carbohydrate to fat of 1:1, 2:1, or 3:1. Food intake, body weight, body length, oxygen consumption, and body composition were measured at ages 21 to 50 d. Serum levels of insulin-like growth factor-1 and leptin were also determined.

RESULTS

Energy intake was similar across groups. The ratio of body weight to body length remained adequate throughout the experimental period. However, groups that received 3:1 and 2:1 showed increased weight and progressive decreases in energy expenditure, body fat composition, and serum level of leptin, but the ratio of insulin-like growth factor-1 to body length was not affected.

CONCLUSIONS

Dietary substitution of fat with carbohydrates contributes to weight gain by decreasing energy expenditure and possibly by decreasing leptin secretion.

[Imbalance diets in preschool children: study in a day-care center in the Province of Buenos Aires, Argentina]

The purpose of this study was to investigate the impact of low fat diets in children aged 2 to 5. Eighty two children (40 females and 42 males) attending a school cafeteria (Province of Buenos Aires, Argentina), in a cross sectional study, were evaluated. Body weight (W), height (H) and body composition (BC) by bioimpedance were recorded. The anthropometric raw data were processed as Z-score of the weight-for-age (WEZ) and of the height-for-age (HAZ). Serum insulin-like growth factor 1 (IGF-1) and Zinc/haemoglobin ratio (Zn/Hb) were also measured. Results showed that 73.2% of the children were adequate (A) according WEZ, 13.4% were lean (L) and 13.4% overweight (O). 8.5% presented simultaneously impairment in WEZ and HAZ. Body fat percentage and energy metabolism were higher in O than in L and A (p < 0.05). Serum IGF-1's children--aged 4 to 5 years--with HAZ deficit were low than adequate HAZ ones. No statistical differences in Zn/Hb ratio between A, L and O were found. This cross sectional study suggests metabolic disorders in young children attending school cafeterias. These conclusions will allow to design balanced diets in order to optimize the resources, promote optimal growth and development and prevent adult diseases through dietary practices in childhood.

Bone growth in nonorganic nutritional dwarfing rats

Since no data are available to characterize mandibular growth in nonorganic nutritional dwarfing (ND), the purpose of the present study was to describe the effects of a diet on mandible and femur growth in a nutritional dwarfish animal model. Male Wistar rats were divided into two groups of 10 animals each: Control (C) and Experimental (E80: diet-restricted group). C rats were fed a standard diet ad libitum. E80 rats received 80% of the amount of standard diet eaten by group C. Food intake and body weight (Wt) and length (Lt) were recorded periodically. Growth data (Wt and Lt) were expressed as a Z-score of weight-for-length (WLZ) ratio, an index of body size. Five animals of each group were selected at random at 4 and 8 weeks and sacrificed. Additionally at t = 0, 5 animals were sacrificed for baseline measurements. Mandibular growth was estimated directly on the right mandible by measuring ten dimensions. Femur growth was estimated from Wt and Lt measurements of the bone. Mandibular weight, area, length and height were negatively affected by dietary restriction during the first 4 weeks of the experimental period. Mandibular growth ceased after this point. Dimensions corresponding to the alveolar unit did not change with time. However, all other dimensions were negatively influenced but not to the same extent. Femur rather than mandibular weight was severely affected. Therefore, the negative effects of the nutritional stress that occurs after weaning would be stronger for the femur, than for the mandible. Femur length was also negatively affected by suboptimal nutrition. In summary, the results of the present study showed that mandible and femur growth respond differently to mild chronic food restriction. These observations could be explained in terms of the different critical bone growth periods and of the time at which nutritional stress was imposed.

Role of crevice in the occurrence of hemoglobin in saliva

The aim of the present study was to analyze the role of the gingival-periodontal component in the presence of blood in saliva. We studied a population of 184 adult patients composed of 101 totally edentulous patients with no oral mucosa lesions and 83 dentulous patients with clinically healthy gums. Saliva samples obtained by spontaneous salivation were collected in sterile containers. Qualitative and quantitative evaluation of each of the samples was performed. 67% of the dentulous patients tested positive for hemoglobin in saliva. None of the patients in the totally edentulous group exhibited hemoglobin in saliva. These data suggest that the periodontal condition is an essential factor for the presence of hemoglobin in saliva.

Biology of TACE inhibition

Studies conducted over the past decade have demonstrated a central role for tumour necrosis factor alpha (TNFalpha) in inflammatory diseases. As a result of this work, a number of biological agents that neutralise the activity of this cytokine have entered the clinic. The recent clinical data obtained with etanercept and infliximab highlight the relevance of this strategy. TNFalpha converting enzyme (TACE) is the metalloproteinase that processes the 26 kDa membrane bound precursor of TNFalpha (proTNFalpha) to the 17 kDa soluble component. Although a number of proteases have been shown to process proTNFalpha, none do so with the efficiency of TACE. A series of orally bioavailable, selective, and potent TACE inhibitors are currently in clinical development. These inhibitors effectively block TACE mediated processing of proTNFalpha and can reduce TNF production by lipopolysaccharide stimulated whole blood by >95%. Through a series of studies it is shown here that >80% of the unprocessed proTNFalpha is degraded intracellularly. The remainder appears to be transiently expressed on the cell surface. Although, in vitro, TACE inhibition has also been implicated in shedding of p55 and p75 surface TNFalpha receptors, the in vivo data cast doubt on the consequences of this finding. In a mouse model of collagen-induced arthritis, the inhibitors are efficacious both prophylactically and therapeutically. The efficacy seen is equivalent to strategies that neutralise TNFalpha. In many studies greater efficacy is observed with the TACE inhibitors, presumably owing to greater penetration to the site of TNFalpha production.

Photochemically enhanced binding of small molecules to the tumor necrosis factor receptor-1 inhibits the binding of TNF-alpha

The binding of tumor necrosis factor alpha (TNF-alpha) to the type-1 TNF receptor (TNFRc1) plays an important role in inflammation. Despite the clinical success of biologics (antibodies, soluble receptors) for treating TNF-based autoimmune conditions, no potent small molecule antagonists have been developed. Our screening of chemical libraries revealed that N-alkyl 5-arylidene-2-thioxo-1,3-thiazolidin-4-ones were antagonists of this protein-protein interaction. After chemical optimization, we discovered IW927, which potently disrupted the binding of TNF-alpha to TNFRc1 (IC(50) = 50 nM) and also blocked TNF-stimulated phosphorylation of Ikappa-B in Ramos cells (IC(50) = 600 nM). This compound did not bind detectably to the related cytokine receptors TNFRc2 or CD40, and did not display any cytotoxicity at concentrations as high as 100 microM. Detailed evaluation of this and related molecules revealed that compounds in this class are "photochemically enhanced" inhibitors, in that they bind reversibly to the TNFRc1 with weak affinity (ca. 40-100 microM) and then covalently modify the receptor via a photochemical reaction. We obtained a crystal structure of IV703 (a close analog of IW927) bound to the TNFRc1. This structure clearly revealed that one of the aromatic rings of the inhibitor was covalently linked to the receptor through the main-chain nitrogen of Ala-62, a residue that has already been implicated in the binding of TNF-alpha to the TNFRc1. When combined with the fact that our inhibitors are reversible binders in light-excluded conditions, the results of the crystallography provide the basis for the rational design of nonphotoreactive inhibitors of the TNF-alpha-TNFRc1 interaction.

Differential regulation of IL-1beta and TNF-alpha RNA expression by MEK1 inhibitor after focal cerebral ischemia in mice

Activation of the extracellular-signal-responsive kinase (ERK 1/2) by MAP kinase/ERK kinase (MEK1/2) following ischemia/reperfusion in the brain has been associated with cell death since inhibition of MEK1/2 provides neuroprotection in cerebral ischemia injury. Since inflammation has been implicated in ischemic brain injury, the present study investigated whether MEK1/2 modifies expression of two key inflammatory cytokines, IL-1beta and TNFalpha, that have been shown to exacerbate ischemic brain injury. A mouse model of transient cerebral ischemia was deployed to test the effect of selective MEK1/2 inhibitor (SL327) on infarct size and cytokine expression. SL327 (100 mg/kg, i.p.) administered 15 min prior to ischemia resulted in 64% reduction in infarct size over controls (n = 8, P < 0.01). Under the same condition, SL327 significantly reduced peak expression of IL-1beta mRNA (59% reduction compared to vehicle, P < 0.01, n = 4) but not TNF-alpha mRNA. A parallel reduction in IL-1beta protein (67%, P < 0.05, n = 6) was also observed using ELISA analysis. These data suggest that the neuroprotective effect of MEK1/2 inhibition may be mediated by suppression of IL-1beta. The study also demonstrates for the first time that these two cytokines are differentially regulated by kinase mediated signaling pathways.

Mutation in the DNA gyrase A Gene of Escherichia coli that expands the quinolone resistance-determining region

In three Escherichia coli mutants, a change (Ala-51 to Val) in the gyrase A protein outside the standard quinolone resistance-determining region (QRDR) lowered the level of quinolone susceptibility more than changes at amino acids 67, 82, 84, and 106 did. Revision of the QRDR to include amino acid 51 is indicated.

Growth deceleration and bone metabolism in nutritional dwarfing rats

Nutritional status as well as energy and protein intake are critical regulators of IGF-1 and IGFBP-3 and contribute to the modulation of bone remodeling and formation. The purpose of this study was to investigate on an experimental model with nutritional dwarfing (ND), whether the alterations on body growth velocity, energy metabolism and body composition could affect serum concentrations of IGF-1 and IGFBP-3 and bone (tibiae and mandible) histology and histomorphometry. Twenty-one male weanling Wistar rats (body weight = 38.20 +/- 0.94 g) were randomized to three groups: seven of them were killed at day = 0 (CO, n = 7); control (C, n = 7); and experimental 80 (E80, n = 7). During 4 weeks, C was fed ad libitum with a 1:1 carbohydrate to fat diet. E80 was being underfed with the same diet by 80% and the following parameters were measured: weight (Wt) for length (L) ratio z-score; oxygen consumption (VO2); body composition (BC) by EM-SCAN SA 3000. At t = 28, E80 and C were killed. Serum IGF-1 and IGFBP-3 and bone histology and histomorphometry were performed on C0, E80 and C. E80 showed Wt for L z-score between lean and adequate, a decrease in VO2 according to body proportions, a BC of a delayed puberty individual, IGF-1 and IGFBP-3 decreased by 56 and 53%, respectively. Tibiae's hematopoyetic and adipose bone marrow areas were combined, with sealing trabeculae on metaphyseal areas. This study suggests that there is a relationship among growth deceleration in ND rats and structural alterations on tibiae.

Ocular findings in aplastic anemia

OBJECTIVE

To analyze the ocular findings in aplastic anemia.

DESIGN

Eighteen patients with aplastic anemia were examined.

RESULTS

Ocular findings included cotton wool spots (38%), nerve fiber layer or preretinal hemorrhages (67%), vitreous hemorrhages (13%), a picture resembling central retinal vein occlusion (13%) and optic disk edema (6%). Preretinal hemorrhages were the presenting sign of aplastic anemia in 2 patients (13%).

CONCLUSIONS

A blood profile is needed in patients with unexplained retinal hemorrhages. Patients with aplastic anemia need to avoid ocular massage and Valsalva maneuvers to decrease ocular morbidity.

The development of the inventory of countertransference behavior

A measure was developed to assess supervisor-perceived countertransference (CT) behavior during counseling sessions. Eleven experts provided face validity for the items, indicating that each item was at least somewhat an expression of countertransference. Exploratory factor analysis of ratings of 126 supervisors of supervisee counseling sessions revealed, as expected, the existence of two factors. However, rather than reflecting the dimensions of overinvolvement and underinvolvement as hypothesized, the factors were better captured by the terms Negative Countertransference and Positive Countertransference. The total scale and each subscale demonstrated high internal consistency. In addition, both positive and negative CT were found to relate positively with an existing one-item index of countertransference behavior and negatively with an existing measure of countertransference management ability. Research and clinical implications are discussed.

Choroidal neovascular membranes: reproducibility of angiographic interpretation

PURPOSE

To determine interobserver agreement for classifying choroidal neovascular membranes in age-related macular degeneration.

METHODS

Six fluorescein angiograms of choroidal neovascular membranes were interpreted by 21 retina specialists. Reliability was measured by percent agreement and kappa coefficient.

RESULTS

Interobserver agreement of membrane types ranged from perfect concordance for a small, classic membrane to near-random classification for a complex pattern. Mean kappa coefficient was.64. Interobserver agreement of membrane size was most variable for intermediate size lesions (mean kappa coefficient =.40).

CONCLUSION

Fluorescein angiographic interpretation of choroidal neovascular membrane type and size can vary considerably. Interobserver agreement is better for membrane type than for membrane size.

The development of the inventory of countertransference behavior

A measure was developed to assess supervisor-perceived countertransference (CT) behavior during counseling sessions. Eleven experts provided face validity for the items, indicating that each item was at least somewhat an expression of countertransference. Exploratory factor analysis of ratings of 126 supervisors of supervisee counseling sessions revealed, as expected, the existence of two factors. However, rather than reflecting the dimensions of overinvolvement and underinvolvement as hypothesized, the factors were better captured by the terms Negative Countertransference and Positive Countertransference. The total scale and each subscale demonstrated high internal consistency. In addition, both positive and negative CT were found to relate positively with an existing one-item index of countertransference behavior and negatively with an existing measure of countertransference management ability. Research and clinical implications are discussed.

Mixed lens opacities and subsequent mortality

BACKGROUND

Previous studies have found an association between cataract or lens opacity and increased risk of mortality. Further work on determining explanatory factors for this association is needed.

OBJECTIVES

To determine, in a population-based cohort of older persons, the 2-year risk of death associated with different types of lens opacities; whether an association of mortality and lens opacity is explained by confounding risk factors such as smoking, diabetes, age, race, and sex, which are known to be related to opacity and mortality; whether lens opacity is a marker for health status; and whether there are differences in cause-specific mortality for persons with and without lens opacity.

MAIN OUTCOME MEASURE

Two-year mortality rate.

METHODS

The Salisbury Eye Evaluation Project consists of a random sample of 2520 residents of Salisbury, Md, aged 65 to 84 years. At baseline, lens photographs were taken to document nuclear, cortical, posterior subcapsular cataract, and mixed opacities. Data on education, smoking, alcohol use, hypertension, diabetes and other comorbid conditions, handgrip strength, and body mass index were also collected. Two-year follow-up was conducted for mortality and cause of death.

RESULTS

Nuclear opacity, particularly severe nuclear opacity, and mixed opacities with nuclear were significant predictors of mortality independent of body mass index, comorbid conditions, smoking, age, race, and sex (mixed nuclear: odds ratio, 2.23; 95% confidence interval, 1.26-3.95).

CONCLUSION

Lens opacity status is an independent predictor of 2-year mortality, an association that could not be explained by potential confounders.

Overexpression of the cat-86 gene is associated with thermosensitivity in Bacillus subtilis

Bacillus subtilis harboring the cat-86 constitutive plasmid pPL708C2 with an ochre mutation at the 9th codon (terc 9) was sensitive to chloramphenicol (Cm(s)) and exhibited relative thermostability when heated at 47 degrees C. Reversion to chloramphenicol resistance (Cm(r)) occurred at a frequency of 5.4 x 10(-8). All of the plasmid Cm(r) revertants tested were thermosensitive. Similarly, wild-type pPL708C2 present in B. subtilis also rendered the bacterium thermosensitive. When a nonsense mutation is introduced at codon 141, however, this terc 141 variant of pPL708C2 failed to thermosensitize B. subtilis. Another variant of pPL708C2 that produces intact yet catalytically inactive CAT-86 has both His-16 and His-17 at the active site replaced by Pro. Nevertheless, cells of B. subtilis carrying this variant were thermosensitive. Plasmid-free and pPL708C2-bearing strains did not exhibit differences in major heat shock proteins. Electron micrographs revealed a threefold increase of inclusion bodies present in a strain harboring pPL708C2 when compared with those in an isogenic plasmid-free strain.

Proliferative response of mantle cell lymphoma cells stimulated by CD40 ligation and IL-4

Mantle cell lymphoma (MCL) is a tumor of intermediate-size, IgM+, IgD+ B cells derived from the mantle zone of the germinal center. Little is known about its specific immunologic features or responsiveness to T cell-derived signals. In this work, we evaluated the proliferation and cell cycle properties of freshly isolated MCL cells after CD40 ligation, in the absence and presence of interleukin 4 (IL-4). In each MCL case examined, there was a marked growth-enhancing effect of these two stimuli characterized by improved viability, augmented expression of Ki-67, and induction of the proliferating cell nuclear antigen (PCNA). Cyclin D1 was expressed throughout the cell cycle in MCL cells induced to enter S phase. From these investigations, we conclude that the biology of MCL B lymphocytes is affected by CD154 (CD40 ligand) and IL-4, two signals usually provided by CD4+ T cells. The capacity to manipulate the activation and cell cycle state of MCL cells by these specific immunological stimuli may be exploited to confer susceptibility to chemotherapy agents and develop novel therapies in this disease.

Optic nerve avulsion secondary to a basketball injury

Optic nerve avulsion secondary to a basketball injury is a rare complication. The patient underwent a vitrectomy for a non-clearing vitreous hemorrhage. The nerve was partially avulsed with multiple choroidal ruptures in the fovea. It was concluded that optic nerve disorders rarely occur after basketball injuries. Patients with a dense vitreous hemorrhage may benefit from a vitrectomy although the vision will be limited by the optic nerve disorder.

A comparison of job satisfaction among nursing assistants in nursing homes and the Program of All-inclusive Care for the Elderly (PACE)

Three hundred forty-nine full-time nursing assistants (NAs) in 5 PACE programs and their neighboring nursing homes were surveyed to assess job satisfaction. There were no significant differences between NAs in the two models of care with respect to demographics, job description, or importance placed on job elements. Job satisfaction, however, was higher among the PACE NAs. PACE NAs reported a significantly higher prevalence of the chance to form close relationships with patients, variety, respect for suggestions by people who make decisions about patient care, the chance to use one's own judgment, the chance to discuss patients with other team members, and respect for choices in assignment type.

[Assessment of normal growth patterns in rats by Z score]

Malnutrition is one of the most important causes of normal growth disruption. Anthropometric methods are highly valuable in clinic pediatric diagnosis to determine the nutritional status of children and as recovery monitoring. In previous studies, we have demonstrated that the standards weight-age, height-age and weight-height of growing rats had similar distribution to those in normal children. However, to improve the diagnostic effectiveness of anthropometric information, statistical analysis to normally and non-normally distributed variables should be applied. One hundred Wistar rats (50 male and 50 female rats) from weaning (day = 25, weight = 35-40 g) to 70 days of age were fed with a commercial diet. Water and diet were offered "ad libitum". Body weight and height were recorded every two or four days, respectively. Percentiles of weight vs age, height vs age and weight vs height were plotted for male and female rats. The statistical criterion for classifying the anthropometric measurements into nutritional categories was based on percentiles cutoff and Z-score. The Z-score was calculated according to: Z = (standard mean value-subject value/standard deviation of standard). The statistical anthropometric categories of growing rats were similar to those obtained in children. This evidence suggest that the rat can be used as an experimental model to infer and predict the nutritional response in children.

Impact of community volunteers on immunization rates of children younger than 2 years

OBJECTIVE

To assess the effectiveness of a volunteer-driven outreach program on immunization rates in children younger than 2 years.

DESIGN

Randomized controlled trial.

SETTING

Pediatric ambulatory clinics in New York, NY.

PATIENTS

A total of 163 children were randomly assigned to receive services from the volunteer-driven outreach program or to serve as control subjects. All children were (1) younger than 2 years, (2) no-shows for a scheduled appointment in the pediatric clinic, and (3) due or overdue for a vaccine.

INTERVENTION

Immunization outreach, tracking, and follow-up were provided by community volunteers throughout follow-up (mean, 6.5 months). Control children were notified of immunization status at enrollment but received no further contact until the conclusion of follow-up (mean, 6.4 months).

MAIN OUTCOME MEASURE

Immunization status 6 months after enrollment.

RESULTS

Significantly more intervention children were up-to-date with their vaccination series than controls (75% vs. 54%; P = .03). Children in the control group were 2.8 times more likely to be late for a vaccine than intervention children (odds ratio = 2.8; P = .02). In addition, an immunization delay of longer than 30 days at enrollment was a significant predictor of final immunization delay (odds ratio = 2.6; P = .02).

CONCLUSIONS

This volunteer-driven program significantly improved immunization rates among intervention children compared with controls. Results confirm previous findings that indicate an increased risk of an incomplete immunization series by 2 years of age among children who fall behind early in their primary vaccination series. However, control children were almost 3 times more likely to be late (for > or =1 vaccines) than intervention children, regardless of whether an earlier immunization delay was present.

Characteristics of discrepancies between self-reported visual function and measured reading speed. Salisbury Eye Evaluation Project Team

PURPOSE

Visual impairment is a risk factor for morbidity in the elderly and is often screened for by self-report. This study evaluates whether there are subsets for whom there is a discrepancy between self-reported and measured function.

METHODS

The prevalence of a discrepancy between self-reported difficulty reading a newspaper and measured reading speed was determined in 2520 community-based men and women, aged 65 to 84 years, and the discrepant group characterized by polychotomous regression.

RESULTS

Of subjects who reported minimal difficulty reading a newspaper, 10.8% (227/2107) read newsprint-sized text (0.21 degrees) more slowly than 80 words/min, a level previously shown to be necessary for sustained reading. Poor visual acuity, presence of psychiatric symptoms, and less satisfaction with vision were associated with being in the group that read slowly and reported difficulty with reading. Better cognition, better visual acuity, more years of education, white race, and fewer psychiatric symptoms were associated with being in the group that read more quickly and reported minimal difficulty. When reading the text size at which subjects read their fastest, only 2.6% of those with minimal difficulty remained discrepant. These individuals were more likely to have less education, be male, be African American, and have poorer cognitive status than those who did not remain discrepant.

CONCLUSIONS

A subset of the elderly population have a substantial discrepancy between self-reported reading difficulty and measured reading speed. In some, this discrepancy may be based on underlying expectations and experiences, and in others it may represent a transition from no visual impairment to visual impairment.

[Nutrition dwarfism: longitudinal analysis of anthropometric and metabolic parameters in rats]

Nutritional dwarfing (ND) is the result of nonorganic causes reflective of a voluntary or unintentional reduction in food intake, inappropriate eating behavior, dissatisfaction with body weight or unhealthy approaches toward weight control. Patients with ND have reached an equilibrium between their genetic growth potential and their nutritional intake. This study was undertaken to compare on a growing rat model the metabolic alterations in terms of substrate utilization (SU), oxygen consumption (VO2) and growth rate velocity. Twenty male weanling Wistar rats were randomized to 3 groups: control (C), experimental 4 (E4) and 8 (E8). C was fed "ad libitum" with a stock diet, E4 and E8 were underfed by 80% of the requirements during four or eight weeks, respectively. During the depletion phase the following measurements were performed: 1a) body weight (Wt), 1b) length, 1c) Weight for Length ratio z-score, 2) Body composition (BC) by EM-SCAN Tobec Model 3 000, Springfield. USA, 3) VO2 by indirect calorimetry, ECO-OXYMAX.

RESULTS

1) wt for length was -0.70 +/- 0.43 for E4 (t = 4 weeks) and 1.44 +/- 0.32 for E8 (t = 8 weeks), 2% of fat mass was within the normal range, 3) VO2 was not significantly different between groups. Chronic suboptimal nutrition (80%) decreased growth velocity which was the sole manifestation of nutritional inadequacy.

Chronic lymphocytic leukemia B cells can express CD40 ligand and demonstrate T-cell type costimulatory capacity

Chronic lymphocytic leukemia (CLL) is characterized by a clonal expansion of CD5(+) B cells in the peripheral blood. Associated immune aberrations include abnormal Th-cell function and pathogenic autoantibodies. Under most circumstances, CLL B cells do not proliferate in culture and express a limited repertoire of surface antigens, including CD19, CD20, CD23, CD27, CD40, and CD70. In this report, we demonstrate that freshly isolated B cells from a subset of CLL cases constitutively express CD40 ligand (CD40L, CD154), a member of the tumor necrosis factor family which is normally expressed by activated CD4(+) T cells and mediates T-cell-dependent B-cell proliferation and antibody production. The degree of CD40L expression varied considerably among the CLL cases examined. CD40L was detected in purified CLL B cells by immunofluorescence flow cytometry, by RT-PCR, and by immunoprecipitation. To demonstrate that CD40L in the CLL B cells is functional, we used irradiated CLL cells to stimulate IgG production by target, nonmalignant B cells in coculture. The CLL B cells induced IgG production by normal B cells to a similar degree as did purified T cells in a process which was partially inhibited by monoclonal antibody to CD40L. This is one of the first reports of CD40L expression in a B-cell tumor. The data suggest that CD40L in the tumor cells may be a factor in the generation of pathologic antibodies by normal B cells in some patients with CLL.

CD40 ligation impedes lymphoblastoid B cell proliferation and S-phase entry

The CD40 cell surface antigen and member of the tumor necrosis factor (TNF) receptor superfamily is expressed in many cell types, including normal and neoplastic B cells. Signaling through CD40 induces B cell proliferation, differentiation and, in some circumstances, protects the B cell from apoptosis. Lymphoblastoid cells (LCLs) resemble the malignant B cells that comprise the Epstein-Barr virus (EBV)-associated posttransplant lymphoproliferative disorders, in that the cells bear a highly activated phenotype and, unlike most other EBV positive tumor cells, express the majority of latent EBV genes. In this study, we use assays of cell viability, proliferation, cell cycle and apoptosis to demonstrate that ligation of the CD40 receptor in EBV-transformed LCLs inhibits their growth. The process does not involve apoptosis, but is characterized by reduced S-phase entry from G0/G1. A better understanding of the negative effects of CD40 ligation in these cells may offer clues for the development of novel therapies in EBV-related B cell disorders.

Influence of dietary calcium concentration on body size and bone composition in rats during recovery from malnutrition

OBJECTIVE

The purpose of our study was to assess the influence of different levels of calcium (Ca) in a diet containing 30% protein on the rehabilitated of the body size from protein-energy malnutrition (PEM) and to establish the optimal Ca/protein ratio for attaining a normal body composition.

METHODS

Weanling female Wistar rats were fed with protein-free diet up to a weight deficit of 20 +/- 1%. Then they were arranged in groups (TO) and fed diets with 30% protein and 0.0, 0.2, 0.4, 0.6, 0.9 or 1.2% Ca for 28 days (T28). Food and deionized water were given ad libitum. Body weight and length were recorded every 3 days. At T28, the animals were sacrificed to determine femur composition.

RESULTS

At T13, weight-for-age (W/A) was within the normal range for rats consuming > or = 0.6% Ca. At T28 all groups showed adequate W/A. Although length-for-age was adequate during rehabilitated period, rate of weight gain improved when Ca was > or = 0.6%. Femur length did not show significant difference between groups. Total femur Ca content and mg Ca/g of dry-weight tissue increased with increments in dietary Ca concentration and tended to plateau with 0.4% Ca. Ca/P ratio reached the highest value with 0.9% Ca.

CONCLUSIONS

Our findings indicate that at a dietary protein level of 30% the Ca/protein ratio is a limiting factor in attaining of normal body size; this is achievable when Ca concentration is 1.2% and the Ca/protein ratio is 0.04.

Structural motifs in rheumatoid T-cell receptors

The linkage of rheumatoid arthritis (RA) to HLA-DR haplotypes, high levels of HLA-DR expression, and T-cell infiltration in the joints, indicate a central role for the interaction of T-cell receptors (TCR) with antigen (Ag) + major histocompatibility complex (MHC) complexes in pathogenesis. Receptor analysis in RA has uncovered a restricted heterogeneity of TCR transcripts, suggesting an antigen-driven response. We analyzed the sequence and structural features of RA-associated TCRs in light of the recently published TCR crystal structures. The surface-exposed residues of the third complementarity-determining region (CDR3s) showed preferential use of certain amino acid residues when sequences derived from synovial fluid or tissue were compared with those derived from peripheral blood, particularly for alpha chains. Sequence alignment of oligoclonal synovial TCR CDR3s revealed groupings with similar CDR3 lengths and amino acid compositions, which suggests shared antigen recognition. Given the limitations of analyzing TCR sequences without knowing their structures, we developed several in vivo-activated synovial-tissue Vbeta17 + RA T-cell clones. Two Vbeta17/V alpha7 clones with different CDR3 sequences were analyzed by molecular modeling. Although distinct topologic features were seen, a central patch of residues with similar chemical and geometric characteristics was present in both. Electrostatic maps revealed similar binding surfaces of both alpha domains and central patches, with differences in the beta domains. This suggests that an alpha-domain-focused binding trajectory would allow shared antigen recognition by these TCRs. These studies support recognition of a limited diversity of Ag + MHC complexes by synovial RA TCRs.

Rapidly progressive herpetic retinal necrosis: a blinding disease characteristic of advanced AIDS

Eleven patients with rapidly progressive herpetic retinal necrosis (RPHRN) complicating AIDS were investigated retrospectively to study the disease spectrum, systemic involvement, and therapy. The mean CD4 cell count was 24/microL. There was a characteristic disease pattern with rapid progression, 82% bilaterality, relative resistance to intravenous antiviral therapy, and 70% retinal detachment. Varicella-zoster virus was the probable cause in 10 patients (detected by polymerase chain reaction in two eyes investigated), and herpes simplex virus was the probable cause in one. Cutaneous zoster occurred previously in 73% but was not concurrent. Seventy-three percent had central nervous system disease, possibly virus-related. RPHRN may be a local herpetic recrudescence in an immune-privileged site with transneural spread. Only four of 20 affected eyes retained useful vision. Poor ocular bioavailability, retinal ischemia, acquired drug resistance, and strain pathogenicity may underlie treatment failure. Acyclovir therapy appears relatively ineffective. Combined intravenous and intravitreal therapy with foscarnet and ganciclovir may be the best current management. Research advances are needed urgently.

Bilateral subinternal limiting membrane hemorrhage with Terson syndrome

PURPOSE

To report the anatomic location of bilateral dome-shaped posterior pole hemorrhages in a patient with Terson syndrome.

METHODS

Case report. We performed bilateral vitrectomy for vitreous hemorrhage in a patient with Terson syndrome. After removal of vitreous hemorrhage, the tissue overlying a large discrete hemorrhage in the posterior pole was removed, and the tissue from one eye was examined histologically.

RESULT

The discrete dome-shaped hemorrhage in the posterior pole was confined to the retina anteriorly by the internal limiting membrane.

CONCLUSION

Large dome-shaped retinal hemorrhages with Terson syndrome can be located beneath the internal limiting membrane of the retina.