How to spot the recurring lumbar disc? Risk factors for recurrent lumbar disc herniation (rLDH) in adult patients with lumbar disc prolapse: a systematic review and meta-analysis

Despite a fast-growing evidence-base examining the relationship of certain clinical and radiological factors such as smoking, BMI and herniation-type with rLDH, there remains much debate around which factors are clinically important. We conducted a systematic review and meta-analysis to identify risk factors for recurrent lumbar disc herniation (rLDH) in adults after primary discectomy. A systematic literature search was carried out using Ovid-Medline, EMBASE, Cochrane library and Web of Science databases from inception to 23rd June-2022. Observational studies of adult patients with radiologically-confirmed rLDH after ≥3 months of the initial surgery were included, and their quality assessed using the Quality-In-Prognostic-Studies (QUIPS) appraisal tool. Meta-analyses of univariate and multivariate data and a sensitivity-analysis for rLDH post-microdiscectomy were performed. Twelve studies (n=4497, mean age:47.3; 34.5% female) were included, and 11 studies (n=4235) meta-analysed. The mean follow-up was 38.4 months. Mean recurrence rate was 13.1% and mean time-to-recurrence was 24.1 months (range: 6-90 months). Clinically, older age (OR:1.04, 95%CI:1.00-1.08, n=1014), diabetes mellitus (OR:3.82, 95%CI:1.58-9.26, n=2330) and smoking (OR:1.80, 95%CI:1.03- 3.14, n=3425) increased likelihood of recurrence. Radiologically, Modic-change type-2 (OR:7.93, 95%CI:5.70-11.05, n=1706) and disc extrusion (OR:12.23, 95%CI:8.60-17.38, n=1706) increased likelihood of recurrence. The evidence did not support an association between rLDH and sex; BMI; occupational labour/driving; alcohol-consumption; Pfirmann- grade, or herniation-level. Older patients, smokers, patients with diabetes, those with type-2 Modic-changes or disc extrusion are more likely to experience rLDH. Higher quality studies with robust adjustment of confounders are required to determine the clinical bearing of all other potential risk factors for rLDH.

Distal retinal ganglion cell axon transport loss and activation of p38 MAPK stress pathway following VEGF-A antagonism

There is increasing evidence that VEGF-A antagonists may be detrimental to neuronal health following ocular administration. Here we investigated firstly the effects of VEGF-A neutralization on retinal neuronal survival in the Ins2^Akita diabetic and JR5558 spontaneous choroidal neovascularization (CNV) mice, and then looked at potential mechanisms contributing to cell death. We detected elevated apoptosis in the ganglion cell layer in both these models following VEGF-A antagonism, indicating that even when vascular pathologies respond to treatment, neurons are still vulnerable to reduced VEGF-A levels. We observed that retinal ganglion cells (RGCs) seemed to be the cells most susceptible to VEGF-A antagonism, so we looked at anterograde transport in these cells, due to their long axons requiring optimal protein and organelle trafficking. Using cholera toxin B-subunit tracer studies, we found a distal reduction in transport in the superior colliculus following VEGF-A neutralization, which occurred prior to net RGC loss. This phenomenon of distal transport loss has been described as a feature of early pathological changes in glaucoma, Alzheimer's and Parkinson's disease models. Furthermore, we observed increased phosphorylation of p38 MAPK and downstream Hsp27 stress pathway signaling in the retinas from these experiments, potentially providing a mechanistic explanation for our findings. These experiments further highlight the possible risks of using VEGF-A antagonists to treat ocular neovascular disease, and suggest that VEGF-A may contribute to the maintenance and function of axonal transport in neurons of the retina.

Stem cells for neuroprotection in glaucoma

Stem cell transplantation is currently being explored as a therapy for many neurodegenerative diseases including glaucoma. Cellular therapies have the potential to provide chronic neuroprotection after a single treatment, and early results have been encouraging in models of spinal cord injury and Parkinson's disease. Stem cells may prove ideal for use in such treatments as they can accumulate at sites of injury in the central nervous system (CNS) and may also offer the possibility of targeted treatment delivery. Numerous stem cell sources exist, with embryonic and fetal stem cells liable to be superseded by adult-derived cells as techniques to modify the potency and differentiation of somatic cells improve. Possible neuroprotective mechanisms offered by stem cell transplantation include the supply of neurotrophic factors and the modulation of matrix metalloproteinases and other components of the CNS environment to facilitate endogenous repair. Though formidable challenges remain, stem cell transplantation remains a promising therapeutic approach in glaucoma. In addition, such studies may also provide important insights relevant to other neurodegenerative diseases.

The chemistry of silica and its potential health benefits

There is considerable interest in the effects of silica on human health in contrast to prior research which focused solely on the toxic effects of inhaled crystalline silica. However, multiple forms of silica exist in nature and silicon, a component, is the second most prevalent element after oxygen. Silica has widespread industrial applications including use as a food additive, i.e., anti-caking agent, as a means to clarify beverages, control viscosity, as an anti-foaming agent, dough modifier, and as an excipient in drugs and vitamins. Chemically, silica is an oxide of silicon, viz., silicon dioxide, and is generally colorless to white and insoluble in water. When associated with metals or minerals the family of silicates is formed. There are several water soluble forms of silica referred collectively to as silicic acid (ortho, meta, di, and tri-silicates), which are present in surface and well water in the range of 1--100 mg/L. Orthosilicic acid is the form predominantly absorbed by humans and is found in numerous tissues including bone, tendons, aorta, liver and kidney. Compelling data suggest that silica is essential for health although no RDI has been established. However, deficiency induces deformities in skull and peripheral bones, poorly formed joints, reduced contents of cartilage, collagen, and disruption of mineral balance in the femur and vertebrae. Very little toxicity data exist regarding aqueous silica consumption due, in part, to the lack of anecdotal reports of toxicity and general presumption of safety. However, a few rodent studies have been conducted, which indicate a No Observed Adverse Effects Level (NOAEL) of 50,000 ppm (mg/L) for dietary silica. In conclusion, many forms of silica exist in nature and compelling data support myriad beneficial effects of silica in water.

Reactive oxygen species as double-edged swords in cellular processes: low-dose cell signaling versus high-dose toxicity

ROS are diverse and abundant in biological systems. While excessive ROS production clearly damages DNA, low levels of ROS affect cell signaling particularly at the level of redox modulation. Moreover, the specific contributions of ROS to apoptosis and mitogenesis in maintenance of cell number homeostasis remains to be elucidated. ROS dose is a critical parameter in determining the ultimate cellular response; however the shape of the dose response curve is unpredictable. When cells are stimulated with ROS, cell-signaling cascades are activated. It appears that the cellular redox potential is an important determinant of cell function and interruption of redox balance may adversely affect cell function. As a result, compounds such as antioxidants may intercept critical ROS signaling molecules and both protect cells and foster pathogenesis. As a result, further study is needed to unravel the role of ROS in redox regulation and the potential outcome of antioxidant administration on cellular responses.

Dietary N-acetyl-L-cysteine modulates benzo[a]pyrene-induced skin tumors in cancer-prone p53 haploinsufficient Tg.AC (v-Ha-ras) mice

Epidemiologic studies support the protective role of dietary antioxidants in preventing cancer. However, emerging evidence from clinical trials and laboratory data suggest that in some cases individual antioxidant supplements may actually exacerbate carcinogenesis. Our goal was to explore these paradoxical activities in a rodent model that possesses genotypic characteristics of human cancers. We selected the p53 haploinsufficient Tg.AC (v-Ha-ras) mouse as a model, because it contains an activated, carcinogeninducible ras oncogene and an inactivated p53 tumor suppressor gene, which are frequent genetic alterations in human cancers. These mice develop chemically induced benign and malignant skin tumors rapidly which can easily be quantified. Mice were fed basal diets with or without 3% N-acetyl-L-cysteine (NAC), a well-recognized antioxidant, prior to, during and after topical application of the carcinogen benzo[a]pyrene (64 microg/mouse) applied twice per week for 7 weeks. Tumor incidence exceeded 90% for both groups, and NAC did not reduce tumor latency. Mice fed NAC displayed a 43% reduction (P < 0.05) in tumor multiplicity and delayed the appearance of lesions (P < 0.05). Dietary NAC also significantly (P < 0.05) improved group survival by 5 weeks. Total tumor yields were reduced in both dietary groups but malignant spindle cell tumors (SCT) increased by 25% in NAC-fed mice. The v-Ha-ras oncogene and p53 protein products were clearly co-expressed in both benign and malignant lesions from both dietary groups. In summary, dietary supplementation with NAC was chemopreventive, but the marginal increase in SCT suggests a paradoxical effect.

N-acetyl-L-cysteine simultaneously increases mitogenesis and suppresses apoptosis in mitogen-stimulated B-lymphocytes from p53 haploinsufficient Tg.AC (v-Ha-ras) mice

Recent epidemiological evidence suggests that antioxidants may enhance carcinogenesis by promoting cellular proliferation and/or impeding programmed cell death. We examined the effect of N-acetyl-l-cysteine (NAC) on mitogenesis and apoptosis in splenocytes from p53 haploinsufficient Tg.AC (v-Ha-ras) mice. This model contains genetic lesions found frequently in human cancer and is predisposed to develop carcinogen-induced cancer. Splenocytes were incubated with NAC alone or with the B- and T-cell-specific mitogens Concanavalin A (Con A) and E. coli lipopolysaccharide (LPS), respectively. Mitogenesis increased 17-fold in mitogen-stimulated cultures and 10-fold in cultures incubated with NAC alone. Co-incubation with both NAC (1000 microg/mL) and mitogen increased mitogenesis by 33-fold without changing apoptosis rates. Strikingly, incubation with NAC and LPS attenuated LPS-induced apoptosis. Mitogen alone did not affect GSH levels but NAC-induced increases were significantly depleted by co-incubation with mitogen. Furthermore, NAC increased the number of CD45R+ B cells, but decreased CD3+ T cells showing enhanced survival of B cells under these conditions. These results demonstrate concurrent reduced apoptosis and increased mitogenesis in B lymphocytes that may favor clonal selection of preneoplastic cells.

Cyclodiode laser therapy for painful, blind glaucomatous eyes

AIMS

To determine the ability of cyclodiode laser treatment to relieve discomfort in painful blind glaucomatous eyes.

METHODS

30 eyes underwent cyclodiode to reduce intraocular pressure (IOP) and relieve pain. Patients graded their pre-cyclodiode and post-cyclodiode pain.

RESULTS

After a minimum follow up of 6 months, a single cyclodiode treatment lowered mean IOP from 51 mm Hg (95% CI plus or minus 3.7 mm Hg) to 26 mm Hg (95% CI plus or minus 5.8 mm Hg) providing pain relief in 73.3% (22/30). After retreatment of six eyes, mean IOP was reduced to 22 (95% CI plus or minus 5.3) mm Hg and pain relief was obtained in 96.7% (29/30). For eyes achieving pain relief after one treatment, IOP was reduced by >30% in 81.0% (17/21). For eyes not achieving pain relief after one treatment, IOP was reduced by >30% in only 22.2% (2/9) (p=0.0042, Fisher's exact test).

CONCLUSION

Cyclodiode was highly successful in providing pain relief in painful blind hypertensive glaucomatous eyes. The best predictor of successful pain relief was IOP reduction of > 30% from baseline.

Who should manage primary retinal detachments?

PURPOSE

To determine whether the outcome of primary retinal reattachment surgery in a subregion is improved by surgery being performed in a specialist vitreoretinal unit (VRU).

METHODS

A subregional, population-based, retrospective audit cycle of primary retinal reattachment surgery was conducted by independent investigators. The subregion was defined as the catchment area of a teaching hospital (TH) with a specialist VRU and three neighbouring district general hospitals (DGHs). During the initial audit period (January 1989 to December 1990), 142 cases were treated at all four hospitals: TH/VRU (83), DGH-A (15), DGH-B (13), and DGH-C (31). Policy changes after the initial audit led to primary retinal reattachment surgery being predominantly performed by the VRU. During the re-audit period (September 1995 to August 1997), 160 cases were treated at two hospitals: VRU (148) and DGH-C (12). The outcome measure employed was complete retinal reattachment after a single procedure with a minimum follow-up of 12 months.

RESULTS

The success rate for primary retinal reattachment surgery in the subregion improved from 76.1% to 88.8% (p = 0.006) following the policy changes. The success rate of the vitreoretinal specialists in the VRU (90%) was greater than the general ophthalmologists in the DGHs (ranging from 47% to 77%), despite case selection by the general ophthalmologists. The number of cases treated by the VRU increased by 156% in the 6.5 year interval between the two audits due to a widespread change in the model of care for primary retinal detachments (both within and outside the subregion). During the re-audit period, the VRU treated 348 primary retinal detachments (including referrals from outside the subregion), achieving a success rate of 86.8% with a single procedure and 97.4% with further surgery. This primary success rate included 35 cases (10%) treated by vitrectomy with silicone oil tamponade who did not undergo silicone oil removal.

CONCLUSIONS

The outcome of primary retinal reattachment surgery can be improved if surgery is performed by a specialist VRU. It is suggested that the current standard for retinal reattachment with a single procedure should be set in the region of 85% to 90%. Changing the model of care so that primary retinal reattachment surgery is predominantly performed by a specialist VRU has important resource implications.

The effect of carotenoids on the expression of cell surface adhesion molecules and binding of monocytes to human aortic endothelial cells

Several large epidemiological studies have shown a correlation between elevated plasma carotenoid levels and decreased risk of cardiovascular disease (CVD). One proposed mechanism for the beneficial effect of carotenoids is through functional modulation of potentially atherogenic processes associated with the vascular endothelium. To test this, we incubated confluent human aortic endothelial cell (HAEC) cultures (passages 4-8) for 24 h with each of the five most prevalent carotenoids in human plasma, which are alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, and lycopene, at an approximate concentration of 1 micromol/l. Carotenoids were solubilized in 0.7% (v/v) tetrahydrofuran and incorporated into FBS before adding to cell culture medium. Due to disparate solubilities in aqueous medium, final concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, and lycopene were 1.7, 1.1, 0.7, 0.9, and 0.3 micromol/l and monolayers accumulated 647, 158, 7, 113, and 9 pmol/mg protein, respectively. Monolayers were then stimulated with IL-1beta (5 ng/ml) for 6 h with subsequent determination of cell surface expression of adhesion molecules as measured by an enzyme-linked immunosorbent assay (ELISA). To assess endothelial cell adhesion to monocytes, IL-1beta-stimulated monolayers were incubated for 10 min with 51Cr-labeled U937 monocytic cells and adhesion determined by isotope counting. Pre-incubation of HAEC with beta-carotene, lutein and lycopene significantly reduced VCAM-1 expression by 29, 28, and 13%, respectively. Pre-incubation with beta-carotene and lutein significantly reduced E-selectin expression by 38 and 34%, respectively. Pre-treatment with beta-carotene, lutein and lycopene significantly reduced the expression of ICAM-1 by 11, 14, and 18%, respectively. While other carotenoids were ineffective, lycopene attenuated both IL-1beta-stimulated and spontaneous HAEC adhesion to U937 monocytic cells by 20 and 25%, respectively. Thus, among the carotenoids, lycopene appears to be most effective in reducing both HAEC adhesion to monocytes and expression of adhesion molecules on the cell surface.

The phacoemulsification learning curve: per-operative complications in the first 3000 cases of an experienced surgeon

PURPOSE

To assess the per-operative complications occurring during the first 3000 phacoemulsification cases performed by an experienced consultant surgeon.

METHODS

A prospective analysis of 3000 consecutive cases performed without supervision between November 1992 and November 1998 was carried out. Data recorded for each case included details of per-operative complications, pre-operative best corrected visual acuity, nuclear density, history of previous pars plana vitrectomy, and whether phacoemulsification was performed as part of a phacotrabeculectomy procedure.

RESULTS

The overall rate of vitreous loss was 1.3%. Nuclear fragments were lost to the vitreous in 6 cases (0.2%). The initial rate of vitreous loss was 4.0% in the first 300 cases falling to 0.7% in the last 300 cases. Capsulorhexis failure was the commonest per-operative complication observed, but the risk of subsequent posterior capsule rupture fell significantly from 9 of 45 (20.0%) in the first 100 cases to 1 of 49 (2.0%) in the next 2000 cases (p = 0.0061, Fisher's exact test). There was a significant increase in risk with denser cataracts, especially for capsulorhexis failure, rising to over 35% in the densest cases. The increases in posterior capsule rupture and vitreous loss were less dramatic but nonetheless very significant. There was no significant increase in the risk of per-operative complications with phacotrabeculectomy, and no increased risk in patients who had previously undergone pars plana vitrectomy. Posterior capsule rupture occurred in 22 of 612 (3.6%) local anaesthesia cases compared with 31 of 2269 (1.4%) topical anaesthesia cases. Per-operative best corrected visual acuity of 6/9 or better was recorded in 2.0% of the first 1000 cases compared with 13.9% of the last 1000 cases.

CONCLUSIONS

(1) Per-operative surgical risks could be reduced to low levels during the learning curve, but complications continued to occur at a low frequency. (2) The risk of per-operative complications was not significantly elevated in previously vitrectomised eyes. (3) Nuclear density correlated significantly with per-operative complication risk. (4) The visual threshold for cataract surgery fell dramatically with increasing experience of phacoemulsification. (5) Topical anaesthesia was not associated with an increased risk of per-operative complications.

In vitro supplementation with different tocopherol homologues can affect the function of immune cells in old mice

Alpha-tocophorel (T) is the most common form of vitamin E inplasma and tissues. Alpha-T is also believed to be superior to its homologues beta-T, gamma-T, and delta-T in antioxidant activity. Biological activity of alpha-T has been intensively studied in a number of bodily systems. In contrast, the other homologues have received little attention beyond the evaluation of their relative antioxidant activity. We as well as others have previously shown that alpha-T can enhance cell- mediated immune function of aged animals and humans. Gamma-T is a principal form of vitamin E in the American diet and some cooking oils contain substantial amount of beta-T and delta-T. Thus it is of public health interest to compare their biological effects with than of alpha-t in various systems. In this study, we used an in vitro supplementation protocol to determine immunologic effects of these T homologues on murine splenocytes. The results showed that all four T homologues enhance both spontaneous and mitogen-stimulated lymphocyte proliferation (LP) and the maximal enhancement produced by them was of the same magnitude. The dose range to produce maximal enhancement varied with different homologues. The efficiency was in the order of beta-T approximately delta-T > alpha-T. Interestingly, at 50 (optimal for alpha-T) and 150 micromol/L, while alpha-T enhanced LP, all the other homologues inhibited LP. This inhibition was found to be due to their cytotoxicity at these levels. T homologues had a differential effect on interleukin (IL)-2 and prostaglandin (PG)E(2) production. IL-2 production by mouse splenocytes was not affected by alpha-T or beta-T, but was increased by gamma-T and delta-T. All T homologues, except for beta-T, inhibited PGE(2) alpha-T. Thus, all the T homologues enhance LP. However, the dose required to reach maximal enhancement varies among the homologues. On the other hand, they have a differential effect on IL-2 and PGE(2) production. The difference in nature and magnitude of the effect on immune function does not correlate with their reported relative antioxidant activity and might be due to minor differences in their structure important to their other biological activities.

Effect of vitamin E on human aortic endothelial cell production of chemokines and adhesion to monocytes

Epidemiological and clinical studies indicate that vitamin E may reduce the risk of cardiovascular disease (CVD). Modulation of adhesion molecule expression and chemokine production by vitamin E may contribute to its beneficial effect. In this study we found that the enrichment of confluent human aortic endothelial cells (HAEC) or U937 monocytic cells with increasing doses of vitamin E (d-alpha-tocopherol, 20, 40, and 60 micromol/l for 20 h) inhibited their adhesion when either or both cell types were stimulated with interleukin (IL)-1beta. Enrichment of HAEC with the same doses of vitamin E suppressed IL-1beta-stimulated expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and endothelial leukocyte adhesion molecule-1 (E-selectin). Supplementation with increasing doses of vitamin E up to 60 micromol/l was not effective in preventing spontaneous production of monocyte chemoattractant protein-1 (MCP-1), but supplementation with vitamin E at 60 micromol/l reduced IL-8 production significantly. However, IL-1beta-induced productions of both MCP-1 and IL-8 were dose-dependently suppressed by enrichment of cells with vitamin E. Vitamin E, at the doses used, did not significantly change the spontaneous production but dose-dependently inhibited the IL-1beta-induced production of inflammatory cytokine IL-6. We concluded that vitamin E could inhibit production of chemokines and inflammatory cytokines, in addition to inhibiting adhesion of HAEC to monocytes by reducing expression of adhesion molecules when cells were activated with an inflammatory cytokine. These mediators are actively involved in the pathogenesis of atherosclerosis. Therefore, their inhibition by vitamin E may contribute to vitamin E's reported reduction in risk of CVD.

Dietary marine algae (Schizochytrium sp.) increases concentrations of conjugated linoleic, docosahexaenoic and transvaccenic acids in milk of dairy cows

Modification of milk fat to contain long-chain (n-3) fatty acids and increased concentrations of conjugated linoleic acid has potential for improving health of consumers. Natural modification of milk through nutritional manipulation of diets for dairy cows is preferable to post-harvest modification. The objectives of this study were to increase the concentrations of beneficial fatty acids in milk fat by feeding a diet rich in (n-3) fatty acids from algae to dairy cows. Cows were fed a control diet, a diet containing algae (Schizochytrium sp.) protected against ruminal biohydrogenation, or a diet containing unprotected algae for 6 wk. Feed intake and milk production were recorded daily. Milk samples were obtained weekly for analysis of milk composition and profile of fatty acids. Percentage of fat in milk of cows fed algae was lower (P < 0.01) than in milk from cows fed the control diet; however, energy-corrected milk production did not differ (P > 0.05). Inclusion of algae in diets decreased (P < 0.01) feed intake. Milk fat from cows fed algae contained greater (P < 0.01) concentrations of conjugated linoleic acid, (n-3) fatty acids (particularly docosahexaenoic acid), and transvaccenic acid. Concentrations of docosahexaenoic acid were greater (P < 0.01) in milk fat from cows fed protected algae compared to milk fat from cows fed unprotected algae. Milk fat from cows fed algae contained lower (P < 0.05) concentrations of total saturated fatty acids compared to cows fed the control diet. In conclusion, milk fat can be modified through nutritional management of dairy cows to provide more favorable fatty acids for consumers.

The effect of long-term dietary supplementation with antioxidants

The impact of diet and specific food groups on aging and age-associated degenerative diseases has been widely recognized in recent years. The modern concept of the free radical theory of aging takes as its basis a shift in the antioxidant/prooxidant balance that leads to increased oxidative stress, dysregulation of cellular function, and aging. In the context of this theory, antioxidants can influence the primary "intrinsic" aging process as well as several secondary age-associated pathological processes. For the latter, several epidemiological and clinical studies have revealed potential roles for dietary antioxidants in the age-associated decline of immune function and the reduction of risk of morbidity and mortality from cancer and heart disease. We reported that long-term supplementation with vitamin E enhances immune function in aged animals and elderly subjects. We have also found that the beneficial effect of vitamin E in the reduction of risk of atherosclerosis is, in part, associated with molecular modulation of the interaction of immune and endothelial cells. Even though the effects of dietary antioxidants on aging have been mostly observed in relation to age-associated diseases, the effects cannot be totally separated from those related to the intrinsic aging process. For modulation of the aging process by antioxidants, earlier reports have indicated that antioxidant feeding increased the median life span of mice to some extent. To further delineate the effect of dietary antioxidants on aging and longevity, middle-aged (18 mo) C57BL/6NIA male mice were fed ad libitum semisynthetic AIN-76 diets supplemented with different antioxidants (vitamin E, glutathione, melatonin, and strawberry extract). We found that dietary antioxidants had no effect on the pathological outcome or on mean and maximum life span of the mice, which was observed despite the reduced level of lipid peroxidation products, 4-hydroxynonenol, in the liver of animals supplemented with vitamin E and strawberry extract (1.34 +/- 0.4 and 1.6 +/- 0.5 nmol/g, respectively) compared to animals fed the control diet (2.35 +/- 1.4 nmol/g). However, vitamin E-supplemented mice had significantly lower lung viral levels following influenza infection, a viral challenge associated with oxidative stress. These and other observations indicate that, at present, the effects of dietary antioxidants are mainly demonstrated in connection with age-associated diseases in which oxidative stress appears to be intimately involved. Further studies are needed to determine the effect of antioxidant supplementation on longevity in the context of moderate caloric restriction.

Disease incidence and longevity are unaltered by dietary antioxidant supplementation initiated during middle age in C57BL/6 mice

The ability of augmented antioxidant consumption to alter disease incidence, lesion burden and/or longevity was studied in adult male C57BL/6 mice. Mice were fed modified AIN76 diet or modified AIN76 supplemented with vitamin E, glutathione (GSH), vitamin E and GSH, melatonin or strawberry extract starting at 18 months of age. All the mice in this study were heavier than reference populations of male C57BL/6 mice fed NIH-07 or NIH-31, which were maintained without a mid-life change in diet. Fatty liver, focal kidney atrophy and proteinacious casts in the renal tubules were observed more frequently in this study population than in the reference populations. Lesion burden and incidence of specific lesions observed amongst the various groups in this study did not differ. There were no differences observed for longevity of any of the study groups. The longevity observed in this study was similar to that previously reported for male C57BL/6 mice. Thus, diet supplementation with antioxidants initiated during middle age did not appear to affect age-associated lesions patterns, lesion burden or longevity for ad libitum fed male C57BL/6 mice.

Estimation of plasma volume in Holstein and Jersey calves

The concentration of immunoglobulin (Ig) G in the blood of neonatal calves shortly after birth is a widely used criterion to determine the degree of acquisition of passive immunity. Another method used to determine the biological mechanisms of IgG absorption is calculation of the apparent efficiency of IgG absorption. Estimation of the efficiency of IgG absorption requires the estimation of plasma volume in neonatal calves. Previous estimates of plasma volume in a few calves of varying breeds have been made; the estimates ranged from 7 to 14.5% of body weight (BW). Holstein (n = 97 from four farms) and Jersey (n = 49 from one farm) calves were fed fresh maternal colostrum or colostrum that had been previously frozen. Calves were fed 2 L of colostrum at 4.1 h (SE = 0.2; range = 0.3 to 11.0 h) and 12 h later. Plasma volume was measured by determining the concentration of Evans' blue dye in a jugular blood sample collected 10 min after injection of approximately 1.5 ml of 1.5% Evans' blue dye. Factors that affected plasma volume (milliliters) were BW, breed, and age at sampling; r2 of the regression was 0.60. Factors that affected plasma volume (percentage of BW) were BW, breed, and age at sampling; r2 of the regression was 0.08. Mean plasma volume for all calves was 3162 ml (SE = 79) and was 9.86% of birth BW (SE = 0.15%). Mean plasma volume was 2250 ml (9.71% of BW) and 3623 ml (9.94% of BW) for Jersey and Holstein calves, respectively. Body weight was the best predictor of plasma volume.

Human lipoproteins as a vehicle for the delivery of beta-carotene and alpha-tocopherol to HepG2 cells

Highly differentiated human cell lines represent a useful in vitro model for the study of carotenoid uptake, metabolism, and function. Carotenoids are usually introduced into tissue culture media either in organic solvents or as micelles, whereas carotenoids are localized in lipoproteins in vivo. Initially, the stability of beta-carotene and alpha-tocopherol in micelles and human lipoproteins under standard tissue culture conditions was compared. Recovery of beta-carotene and alpha-tocopherol was 27% +/- 2% and 73% +/- 2%, respectively, after overnight incubation of micellar beta-carotene and alpha-tocopherol in serum-free medium without cells. This marked loss of beta-carotene was attenuated by inclusion of alpha-tocopherol in micelles. In contrast, recovery of beta-carotene and alpha-tocopherol was 88%-95% when medium containing the total lipoprotein fraction isolated from beta-carotene supplemented individuals was incubated overnight without cells. Cellular accumulation of beta-carotene and alpha-tocopherol from medium containing total lipoproteins (1 mg/ml) was proportional to their concentrations in the lipoprotein fraction (r = 0.94 for beta-carotene and 0.74 for alpha-tocopherol). Cells exhibited similar capability of acquiring beta-carotene and alpha-tocopherol from medium containing either low- or high-density lipoproteins. These data show that lipoproteins represent a stable vehicle for delivery of beta-carotene and alpha-tocopherol to HepG2 human liver cells.

Beta-carotene and lutein protect HepG2 human liver cells against oxidant-induced damage

Numerous epidemiological studies support a strong inverse relationship between consumption of carotenoid-rich fruits and vegetables and the incidence of some degenerative diseases. One proposed mechanism of protection by carotenoids centers on their putative antioxidant activity, although direct evidence in support of this contention is limited at the cellular level. The antioxidant potential of beta-carotene (BC) and lutein (LUT), carotenoids with or without provitamin A activity, respectively, was evaluated using the human liver cell line HepG2. Pilot studies showed that a 90-min exposure of confluent cultures to 500 mumol/L tert-butylhydroperoxide (TBHP) at 37 degrees C significantly (P < 0.05) increased lipid peroxidation and cellular leakage of lactate dehydrogenase (LDH), and decreased the uptake of 3H-alpha-aminoisobutyric acid and 3H-2-deoxyglucose. Protein synthesis, mitochondrial activity and glucose oxidation were not affected by TBHP treatment, suggesting that the plasma membrane was the primary site of TBHP-induced damage. Overnight incubation of cultures with > or = 1 mumol/L dl-alpha-tocopherol protected cells against oxidant-induced changes. In parallel studies, overnight incubation of HepG2 in medium containing micelles with either BC or LUT (final concentrations of 1.1 and 10.9 mumol/L, respectively), the cell content of the carotenoids increased from < 0.04 to 0.32 and 3.39 nmol/mg protein, respectively. Carotenoid-loaded cells were partially or completely protected against oxidant-induced changes in lipid peroxidation, LDH release and amino acid and deoxyglucose transport. These data demonstrate that BC and LUT or their metabolites protect HepG2 cells against oxidant-induced damage and that the protective effect is independent of provitamin A activity.

Concentrations of trypsin inhibitor and immunoglobulins in colostrum of Jersey cows

Colostrum samples from 49 Jersey cows were analyzed for concentrations of trypsin inhibitor, IgG, IgM, IgA, TS, fat, specific gravity, and N fractions. Colostrum (100 ml) was sampled from each cow as soon as possible after parturition. Mean concentrations of IgG, IgM, and IgA were 84.6, 3.4, and 4.5 g/L, respectively. Mean concentration of trypsin inhibitor was 56 mg of trypsin inhibited/dl of colostrum. Concentration of trypsin inhibitor was unaffected by lactation number and averaged 60, 53, and 54 mg of trypsin inhibited/dl of colostrum for cows in first, second, and third or later lactations, respectively. Colostral trypsin inhibitor and IgG were correlated (.54), although correlations between trypsin inhibitor and IgM and IgA were not significant. Trypsin inhibitor in colostrum was also positively correlated with fat, total N, protein N, noncasein N, and TS in colostrum. Variation in concentration of trypsin inhibitor from first-milking colostrum was closely related to colostral IgG concentration and may serve to protect IgG and other proteins from proteolytic degradation in the intestine of the neonatal calf.

Immunoglobulin concentrations in serum in response to injectable immunoglobulin in neonatal dairy calves

Thirty Holstein bull calves were used to investigate the use of an injectable solution of purified Ig to increase Ig in serum of neonatal calves. The Ig were from abbatoir blood purified by column chromatography. Calves were blocked by date of birth and assigned randomly to treatment within block. Treatments were s.c. injections of Ig solution (30 or 60 mg of Ig/ml) or .9% NaCl with or without colostrum (41.1 g of IgG/L) feeding. Calves were injected by 24 h of age. The mass of Ig injected was 1.05 g/kg of BW. Calves received 2 L of pooled colostrum or commercial milk replacer at 0, 12, 24, and 36 h. Blood was sampled at 0 and 48 h postinjection and at 28 d of age, and serum was analyzed for IgG and IgM by radial immunodiffusion. Mean IgG and IgM in serum of calves injected with Ig were 4.2 and .7 g/L, respectively, and were higher than in calves receiving no Ig. Mean IgG (14.6 g/L) and IgM (1.0 g/L) concentrations in serum of calves fed colostrum were higher than in other calves. Subcutaneous Ig provided moderate amounts Ig in serum.

Effects of housing and colostrum feeding on serum immunoglobulins, growth, and fecal scores of Jersey calves

Ninety-six Jersey calves were used to evaluate the effects of housing and method of colostrum feeding on serum Ig concentrations, incidence and severity of scours, intake, and BW changes from birth to 35 d of age. Calves were separated from the dam and fed 2 L of colostrum in nipple-bottles or allowed to nurse the dam for 3 d. Calves were housed in individual hutches or wooden pens in a barn. Intake of colostrum by calves allowed to nurse the dam was not controlled. Serum IgG and IgM concentrations at 24 h of age were greater for calves that nursed the dam. Scours were less severe when calves were housed in hutches, but number of days scouring was unaffected by treatment. Calves fed colostrum in nipple-bottles and housed in the barn consumed more starter than did other calves from 3 to 5 wk of age. The BW were greater for calves allowed to nurse the dam and housed in hutches. Feed efficiency over the 35-d study was improved when calves nursed the dam. Optimal transfer of passive immunity and housing in hutches appeared to maximize health and growth in this study.

Addition of soybean trypsin inhibitor to bovine colostrum: effects on serum immunoglobulin concentrations in Jersey calves

Secretion of trypsin by the neonate may reduce absorption of Ig from colostrum and increase failure of transfer of passive immunity, particularly for calves fed after 12 h of age. Jersey calves (n = 48) were used in a 2 x 2 factorial arrangement of soybean trypsin inhibitor (0 or 1 g) added to 1 L of maternal colostrum at the first two feedings and time of initial feeding (.65 or 12 h of age). A second colostrum feeding was offered 12 h after the initial feeding. Maternal colostrum was analyzed for Ig by radial immunodiffusion and trypsin inhibitor by radial protease diffusion. Jugular blood was sampled at 0, 12, 24, and 48 h after initial feeding, and serum was analyzed for IgG and IgM. Addition of trypsin inhibitor increased serum Ig and total serum protein concentrations, regardless of age at first feeding. Concentrations of serum IgG and IgM were increased 16 and 30%, respectively, when trypsin inhibitor was fed. Age of first feeding did not affect concentrations of IgG or IgM in serum. Supplementation of colostrum with trypsin inhibitor improved transfer of passive immunity to neonatal Jersey calves.

Protein and energy balance following femoral neck fracture in geriatric patients

To elucidate the effect of total peripheral parenteral nutrition (TPPN) on protein kinetics following injury, we compared the whole-body leucine kinetic response using a primed-constant infusion of L-[1-14C]leucine in 33 elderly patients (aged 82 +/- 1.0 years) following hip fracture and 33 healthy elderly control subjects (aged 75 +/- 0.7 years). Following a 36-hour fast, leucine release from protein breakdown was 1.2 +/- 0.10 mumol.kg-1.min-1 and leucine incorporation into protein was 0.94 +/- 0.095 mumol.kg-1.min-1 in control subjects, and in injured subjects leucine release from protein breakdown was 1.3 +/- 0.14 mumol.kg-1.min-1 and leucine incorporation into protein was 0.97 +/- 0.092 mumol.kg-1.min-1. Control and injured subjects were then administered TPPN (protein, 1.5 g amino acids.kg-1; carbohydrate, 10.0 kcal.kg-1; lipid, 15.0 kcal.kg-1) for 24 hours, and leucine kinetics were redetermined. Compared with protein kinetics in the fasting state, leucine release from protein decreased to 1.0 +/- 0.14 mumol.kg-1.min-1 and leucine incorporation into protein increased to 1.16 +/- 0.097 mumol.kg-1.min-1 in control subjects. Injured patients also responded to TPPN with a decrease in leucine release from protein breakdown (1.12 +/- 0.156 mumol.kg-1.min-1) and an increase in leucine incorporation into protein (1.29 +/- 0.164 mumol.kg-1.min-1). These results indicate that in a geriatric population, whole-body leucine kinetics following hip fracture and the anabolic response to TPPN are not significantly altered from those of uninjured subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of housing and colostrum feeding on the prevalence of selected infectious organisms in feces of Jersey calves

Neonatal Jersey calves (n = 96) were used to evaluate effects of housing (individual hutches or wooden pens in a barn) and colostrum feeding (calves were separated from the dam and fed 2 L of colostrum in nipple-bottles or allowed to nurse the dam for 3 d) on the prevalence of selected organisms in feces. Prevalence of Cryptosporidium and Eimeria were reduced, and prevalence of rotavirus tended to be reduced, when calves were housed in hutches. Prevalence of coronavirus was unaffected by treatment. Weekly prevalence of Giardia was increased when calves were left to nurse the dam for 3 d. Mean prevalence of Cryptosporidia (wk 1 to 4), Eimeria (wk 4 to 5), Giardia, rotavirus, and coronavirus (wk 1 to 5) were 34.7, 20.6, 27.1, 15.8, and 4.9%, respectively. Escherichia coli (K99 positive) were observed in 3 of 174 samples cultured. Methods of housing and colostrum feeding affected acquisition of enteropathogens in this study.

Response of peripheral blood mononuclear cells to mitogenic stimulation in young calves

Sixteen Holstein bull calves were used to evaluate effects of increasing blood BHBA, as a consequence of ruminal development, on response of peripheral blood mononuclear cells to mitogenic stimulation. Calves were blocked by date of birth and assigned to weaning at 35 or 49 d of the study. Calves began the study at 4 d of age. Milk replacer was fed at 10% of BW to d 7 prior to weaning; thereafter, milk replacer offered was reduced by 50%. Calf starter was offered from d 1. Blood was sampled at wk 0, 2, 4, 6, 8, and 10 at 4 h after the a.m. feeding. Blood glucose declined, and blood BHBA increased, as calf starter intake increased. Blood BHBA increased at weaning in each treatment group and exceeded 1 mM during the week of weaning. Responses of peripheral blood mononuclear cells to stimulation with concanavalin A, pokeweed mitogen, or phytohemagglutinin were unaffected by increasing blood BHBA and increased with age. Increased concentration of blood BHBA in young calves from increased starter intake did not impair immune response.

Immunoglobulin concentration, specific gravity, and nitrogen fractions of colostrum from Jersey cattle

Colostrum samples from 88 Jersey cows were analyzed for concentrations of IgG, IgM, IgA, total solids, specific gravity, and N fractions. Colostrum (50 ml) was sampled from each cow as soon as possible after parturition, and specific gravity was determined immediately using a hydrometer. Samples then were frozen prior to analysis of Ig, fat, and N fractions. Mean concentrations of IgG, IgM, and IgA were 65.8, 2.4, and 1.7 g/L, respectively. Concentration of IgG was lower, and IgA was higher, in colostrum from second lactation cows than from first lactation cows or from cows in third or later lactations; IgM increased linearly as lactation number increased. Total N, protein N, noncasein N, and fat contents also were lower in second lactation cows. Regression of total Ig (grams per liter) on specific gravity was -1172 + 1180 x specific gravity (r2 = .38). Relationship of total Ig to specific gravity differed from colostrum of Holstein cattle and may have been related to differences in fat and noncasein N concentrations. Use of specific gravity hydrometer to estimate Ig concentration using equations derived from Holstein cattle appears to underestimate Ig concentration in colostrum from Jersey cattle.

Intake, growth, and selected blood parameters in calves fed calf starter via bucket or bottle

Calf starter was offered to 40 calves in a plastic bucket or from a nipple bottle, and intake, growth, and selected blood parameters were measured. The nipple was designed with a large opening to allow feed particles to pass through the nipple during meals. Calves began the study at 7 d of age and were fed for 56 d. A commercially prepared calf starter was offered for ad libitum consumption from d 1 of the study, and commercial milk replacer was offered at 10% of BW to weaning at 6 wk of the study. No effects of treatment on intake, rates of gain, feed efficiency, blood BHBA or plasma glucose, urea N, or NEFA were observed. Consumption of starter DM exceeded 1.9 kg/d by wk 8 of the study. Concentration of blood parameters changed in a fashion consistent with developing ruminal function. Calf starter fed from a plastic nipple bottle promoted starter intake as effectively as did starter fed from plastic buckets.

Obstructive jaundice secondary to primary biliary involvement with Hodgkin's disease

A 41-yr-old man presented with jaundice, night sweats, and weight loss. The patient had been on phenytoin for seizure disorder. The drug was discontinued, and a diminution of bilirubin and transaminases occurred over several weeks. Percutaneous liver biopsy revaled cholestasis at the time of maximal hyperbilirubinemia. Recurrent jaundice ensued several weeks later, and an ERCP revealed a common bile duct lesion. Laparotomy revealed Hodgkin's disease involving the common bile duct and periportal node. This cause represents the first report of extrahepatic biliary obstruction from Hodgkin's disease.

The significance of articulator capability. Part II: The prevalence of immediate side shift

The occurrence of immediate side shift of the mandible is frequent enough that the restorative dentist must either use an articular system that adjusts for its presence or must carefully check and adjusts for occlusal interferences intraorally at the time of try-in. However, the prevalence and degree of immediate side shift do not indicate that a fully adjustable articulator is required for all patients.