Role of calpain in spinal cord injury: effects of calpain and free radical inhibitors

The demonstration of increased calpain activity, immunostaining, and expression at the gene (mRNA) and protein levels concomitant with ultrastructural degeneration and loss of axon and myelin proteins in lesioned cord have implicated a pivotal role for calpain in tissue destruction in spinal cord injury (SCI). Calpain, stimulated by free radicals, also mediates apoptotic cell death. These findings suggested that the use of calpain and lipid peroxidation drugs as therapeutic agents would protect cells and maintain the axon-myelin structural unit by preventing protein degradation. In order to examine this hypothesis, we treated SCI animals with calpain inhibitors (calpeptin) and/or methlprednisolone (MP), and antiinflammatory and free-radical inhibitor. SCI (40 g/cm) was induced by weight-drop, and 1 mg calpeptin or 165 mg MP/kg were given intravenously (i.v.) for 24 hours. Untreated injured animals receiving vehicle served as controls. Lesion 68-kDa and 200-kDa neurofilament proteins (NFPs) were analyzed by sodium dodecylsulfate polyarcylamide gel electrophoresis (SDS-PAGE) and chemiluminescence, and the extent of protein loss was quantitated. Loss of protein in the lesion of untreated cord amounted to 47% compared to sham control, while that for calpeptin- or MP-treated rats was 25-30%. Combination treatment with calpeptin and MP was slightly more effective in preventing NFP degradation, compared to either when used alone. Apopotic cell death in SCI as characterized by internucleosomal DNA fragmentation was also reduced following treatment with the inhibitors. The inhibition of cytoskeletal protein degradation suggests that calpain and free-radical inhibitors may rescue cells and preserve and maintain membrane structure by preventing protein breakdown, preserving motor function, and being neuroprotective.

Interactional processes in families with depressed and non-depressed adolescents: reinforcement of depressive behavior

Problem-solving interactions were observed in 86 families of depressed adolescents and 408 families of non-depressed adolescents. Sequential analyses indicated that mothers of depressed adolescents were more likely than mothers of non-depressed adolescents to increase facilitative behavior in response to adolescent depressive behavior. Additionally, fathers of depressed adolescents were more likely than their counterparts in families of non-depressed adolescents to decrease aggressive behavior subsequent to adolescent depressive behavior. These analyses suggest that parents of depressed adolescents may be inadvertently reinforcing depressive behavior. Decreases in adolescent depressive symptomatology from year 1 to year 2 were not accompanied by changes in family interaction patterns.

Solution structure of the C-terminal SH2 domain of the p85 alpha regulatory subunit of phosphoinositide 3-kinase

Heterodimeric class IA phosphoinositide 3-kinase (PI 3-kinase) plays a crucial role in a variety of cellular signalling events downstream of a number of cell-surface receptor tyrosine kinases. Activation of the enzyme is effected in part by the binding of two Src homology-2 domains (SH2) of the 85 kDa regulatory subunit to specific phosphotyrosine-containing peptide motifs within activated cytoplasmic receptor domains. The solution structure of the uncomplexed C-terminal SH2 (C-SH2) domain of the p85 alpha subunit of PI 3-kinase has been determined by means of multinuclear, double and triple-resonance NMR experiments and restrained molecular-dynamics simulated-annealing calculations. The solution structure clearly indicates that the uncomplexed C-SH2 domain conforms to the consensus polypeptide fold exhibited by other SH2 domains, with an additional short helical element at the N terminus. In particular, the C-SH2 structure is very similar to both the p85 alpha N-terminal SH2 domain (N-SH2) and the Src SH2 domain with a root mean square difference (rmsd) for 44 C alpha atoms of 1.09 and 0.89 A, respectively. The canonical BC, EF and BG loops are less well-defined by the experimental restraints and show greater variability in the ensemble of C-SH2 conformers. The lower level of definition in these regions may reflect the presence of conformational disorder, an interpretation supported by the absence or broadening of backbone and side-chain NMR resonances for some of these residues. NMR experiments were performed, where C-SH2 was titrated with phosphotyrosine-containing peptides corresponding to p85 alpha recognition sites in the cytoplasmic domain of the platelet-derived growth-factor receptor. The ligand-induced chemical-shift perturbations indicate the amino-acid residues in C-SH2 involved in peptide recognition follow the pattern predicted from homologous complexes. A series of C-SH2 mutants was generated and tested for phosphotyrosine peptide binding by surface plasmon resonance. Mutation of the invariant Arg36 (beta B5) to Met completely abolishes phosphopeptide binding. Mutation of each of Ser38, Ser39 or Lys40 in the BC loop to Ala reduces the affinity of C-SH2 for a cognate phosphopeptide, as does mutation of His93 (BG5) to Asn. These effects are consistent with the involvement of the BC loop and BG loops regions in ligation of phosphopeptide ligands. Mutation of Cys57 (beta D5) in C-SH2 to Ile, the corresponding residue type in the p85 alpha N-SH2 domain, results in a change in peptide binding selectivity of C-SH2 towards that demonstrated by p85 alpha N-SH2. This pattern of p85 alpha phosphopeptide binding specificity is interpreted in terms of a model of the p85 alpha/PDGF-receptor interaction.

Increased density of glutamate/N-methyl-D-aspartate receptors in putamen from schizophrenic patients

Saturable radioligand binding of [3H]L-689,560 to the glycine site of the N-methyl-D-aspartate (NMDA) glutamate receptor complex was employed to determine the density of this receptor in putamen, caudate and nucleus accumbens taken post mortem from schizophrenic patients and matched controls. Receptor density was found to be significantly increased in putamen of schizophrenics (P=0.012), although no significant change was found in the other two areas studied. Further experiments following 21 days administration of haloperidol to rats provided no evidence that the increase was related to prior drug treatment.

A lasting public health response to an outbreak of HIV infection in a Scottish prison?

Between April and June 1993, 8 cases of acute clinical hepatitis B infection and 2 seroconversions to HIV infection were detected among drug injecting inmates of HM Prison Glenochil in Scotland. To prevent the further spread of infection, an initiative which involved counselling and voluntary attributable HIV testing was conducted over a 10-day period commencing at the end of June. A team of 18 counsellors and phlebotomists was brought together rapidly as part of a unique organizational exercise in the field of public health. Fourteen cases of HIV infection were identified of which 13 were almost certainly infected in Glenochil. Following the exercise, a range of harm reduction measures for injecting prisoners was introduced; these included the availability of hepatitis B vaccine, provision of bleach tablets which could be used to clean injecting equipment, a methadone detoxification programme, increased training for prison officers and improved access to drug and harm minimization counselling for inmates. By mid-1996 all these measures had been sustained and several could be found in many other prisons throughout Scotland. Follow-up investigations showed no evidence of epidemic spread of HIV during the 12 months after the initiative. While the frequency of injecting and needle/syringe sharing may have decreased over the last 3 years, these activities are still being reported and it is highly likely that transmissions of bloodborne infections, in particular hepatitis C, continue to occur. The surveillance and prevention of infections associated with injecting drug use in the prison setting remain a high public health priority.

Rn Delegation: the New Jersey Task Force recommendations

Because licensure and delegation clauses are determined state by state, all statewide home care associations need to begin a dialogue concerning delegation and how it impacts the nurse's practice and the way agencies deliver care in the community. State organizations need to communicate with each other and share concerns and experiences with other state home care organizations. Nursing boards, nursing and home health aide associations, advocates for long-term care patients, and the older population also need to be involved in the discussion. This open dialogue between many different organizations concerning delegation will ensure that patients receive safe, quality care that is also cost effective.

Long-term trial of deferiprone in 51 transfusion-dependent iron overloaded patients

Fifty-one transfusion-dependent iron-loaded adult patients (38 with thalassemia major) were treated with the orally active iron chelator deferiprone (1,2 dimethyl-3-hydroxypyrid-4-one, L1) at a dose of 75 mg/kg/d (range, 50 to 79). Twenty patients discontinued the drug and five died after a mean of 18.7 months (range, 4 to 35). Of the 20, 5 had arthropathy, 5 had gastrointestinal symptoms, 4 had a rising serum ferritin, 3 had agranulocytosis or neutropenia, 1 had tachycardia, 1 had renal failure, and 1 went abroad. Twenty-six patients continued deferiprone for a mean of 39.4 months (range, 12 to 49). Among these patients, there was no overall significant change in serum ferritin (initial mean, 2,937 microg/L; range, 980 to 5,970; final mean, 2,323 microg/L; range, 825 to 5,970) or in urine iron excretion (initial mean, 31.2 mg/24 h; range, 16.3 to 58. 2; final mean, 32.1 mg/24 h; range, 9.4 to 75.8), implying no overall change in iron stores. When the patients who had received deferiprone for longer than 3 years were considered separately, there was also no significant change in serum ferritin or urinary iron excretion. The initial serum ferritin levels in the 26 patients who continued deferiprone treatment were significantly lower than in those who discontinued the drug (P < .01). The liver iron content in 17 patients who had received deferiprone for 24 to 48 months ranged from 5.9 to 41.2 mg/g dry weight, 50% having levels above 15.0 mg, a level associated with a high risk of cardiac disease due to iron overload. In this study the drug caused fewer side effects and was more effective at maintaining iron status among patients previously well chelated and with lower initial serum ferritin levels.

Prospective study of equine colic incidence and mortality

A prospective study of one year was conducted on 31 horse farms to obtain population based estimates of incidence, morbidity and mortality rates of equine colic. Farms with greater than 20 horses were enrolled by randomly selecting horse owners from 2 adjacent counties of Virginia and Maryland. Descriptive information for 1427 horses was collected at the initiation of the study and updated at 3 month intervals. Time on the farm during the study was tabulated for each horse. When colic was reported by the owner, investigators visited the farm to obtain information about the colic. The crude incidence density rate of colic was 10.6 colic cases/100 horse-years, based on 104 cases/358,991 horse-days. The median farm specific incidence density rate was 7 cases/100 horse-years, and the range for individual farms varied from 0 to 30 colic cases/100 horse-years. A specific diagnosis was not made for 84 (81%) of colic episodes. Seventy colic episodes (67%) were treated by a veterinarian. Drugs were used in 83 (80%) colic episodes, and 78 (75%) of colic cases were mild, requiring no treatment or resolving after only one treatment. Four horses required colic surgery. Fourteen (13%) horses had more than one episode of colic during the year. Mortality from all causes of death was 2.5 deaths/100 horse-years, mortality rate for colic was 0.7 deaths/100 horse-years. Proportional mortality rate of colic, 28%, was higher than for any other cause of death. Horses less than age 2 years or greater than age 10 years had lower incidence than horses age 2-10 years. No difference in colic risk between genders was identified. Arabian horses had the lowest and Thoroughbreds the highest breed specific incidence rates. Horses used for eventing, or in training had a statistically significant higher incidence rate of colic compared to mature horses with no use (pets, retired, on pasture with no stated purpose). Horses used for lessons or with no use had the lowest incidence rates.

Prospective study of equine colic risk factors

A 1 year prospective study was conducted on 31 horse farms to identify risk factors for equine colic. Farms were randomly selected from a list from 2 adjacent counties of Virginia and Maryland, USA. The association between colic and farm or individual horse risk factors related to management, housing, pasture, use, nutrition, health and events was first examined by univariate statistical analysis. Individually significant (P < = 0.25 for farm factors, P < = 0.10 for horse factors) variables were used in a stepwise multivariable forward logistic regression to select explanatory factors (P < = 0.05). Analysis was conducted at 2 levels: farm and individual horse with farm specified as a random effects variable. No farm-level variables were significant. Significant horse-level variables included: age, odds ratio (OR) = 2.8 for horses age 2-10 years compared to < 2 years; history of previous colic, OR = 3.6 relative to no colic; changes in concentrate feeding during the year (1 per year, OR = 3.6, more than 1, OR = 2.2) relative to no changes; more than 1 change in hay feeding during the year, OR = 2.1 relative to no changes; feeding high levels of concentrate (> 2.5 kg/day dry matter, OR = 4.8, > 5 kg/day dry matter, OR = 6.3) relative to feeding no concentrate; and vaccination with monocytic ehrlichiosis vaccine during the study, OR = 2.0 relative to no vaccination. Feeding a whole grain with or without other concentrate components reduced risk, OR = 0.4, relative to feeding no whole grain. Results of the study suggest that diet and changes in diet are important risks for colic in a population of horses on farms.

Benzidine-DNA adduct levels in human peripheral white blood cells significantly correlate with levels in exfoliated urothelial cells

In a cross-sectional study of 33 workers exposed to benzidine and benzidine dyes and 15 non-exposed controls, we previously reported that exposure status and internal dose of benzidine metabolites were strongly correlated with the levels of specific benzidine-DNA adducts in exfoliated urothelial cells. We also evaluated DNA adduct levels in peripheral white blood cells (WBC) of a subset of 18 exposed workers and 7 controls selected to represent a wide range of adducts in exfoliated urothelial cells. Samples were coded and then DNA was analyzed using 32P-postlabeling, along with n-butanol extraction. One adduct, which co-chromatographed with a synthetic N-(3'-phospho-deoxyguanosin-8-yl)-N'-acetylbenzidine standard, predominated in those samples with adducts present. The median level (range) of this adduct in WBC DNA was 194.4 (3.2-975) RAL x 10(9) in exposed workers and 1.4 (0.1-6.4) in the control subjects (p = 0.0002, Wilcoxon Rank Sum Test). There was a striking correlation between WBC and exfoliated urothelial cell adduct levels (Pearson r = 0.84, p < 0.001) among exposed subjects. In addition, the sum of urinary benzidine, N-acetylbenzidine and N,N'-diacetylbenzidine correlated with the levels of this adduct in both tissues. This is the first study in humans to show a relationship for a specific carcinogen adduct in a surrogate tissue and in urothelial cells, the target for urinary bladder cancer.

Deficits of [3H]D-aspartate binding to glutamate uptake sites in striatal and accumbens tissue in patients with schizophrenia

The hypothesis involving glutamate in the neuropathology of schizophrenia has attracted great interest. Several studies report dysfunctions in glutamatergic systems, including alterations in kainate and N-methyl-D-aspartate (NMDA) receptors in various areas, as well as changes in the number of glutamate uptake sites. We have studied this further using [3H]D-aspartate binding to glutamate uptake sites as a measure of the integrity of presynaptic glutamate systems in several areas (caudate nucleus, putamen, nucleus accumbens, frontal cortex and temporal cortex) of brain tissue taken at autopsy from schizophrenic patients and controls. A significant decrease in the number of glutamate uptake sites was apparent in caudate nucleus, putamen and nucleus accumbens in the schizophrenia group, indicating an impaired glutamatergic innervation of these subcortical regions. However, no significant changes were found in the two cortical regions studied.

Systemic lupus erythematosus-associated lymphoproliferative disorder: report of a case and discussion in light of the literature

A case of autoimmune disease-associated lymphadenopathy (ADAL) with histological, immunophenotypic, Epstein-Barr virus (EBV) in situ hybridization, and genotypic analyses is presented. The patient had a well-documented history of systemic lupus erythematosus (SLE) and was found at autopsy to have massive lymphadenopathy, thymic enlargement, pulmonary nodules, and polyclonal serum dysproteinemia. Histological examination revealed a polymorphous lymphoid infiltrate containing many plasma cells, rare immunoblasts, and a pronounced arborizing vasculature. No foci of necrosis were found and there was no evidence of lymphocyte depletion. The plasma cells were immunophenotypically polyclonal and no EBV mRNA (EBER-1) or gene rearrangements were identified. The unusual gross features, which resembled a malignant lymphoproliferative process, as well as the unusual histological features make this case a notable addition to the spectrum of atypical lymphoproliferative disorders associated with an autoimmune disorder. We conclude that although reminiscent of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD), this case lacks the diagnostic features of AILD, and is, perhaps, best classified as an autoimmune disease-associated lymphadenopathy (ADAL).

Family support and conflict: prospective relations to adolescent depression

The relations between family support, family conflict, and adolescent depressive symptomatology were examined longitudinally in a sample of 231 female and 189 male adolescents and their mothers. Structural equation models revealed that less supportive and more conflictual family environments were associated with greater depressive symptomatology both concurrently and prospectively over a 1-year period. Conversely, adolescent depressive symptomatology did not predict deterioration in family relationships. Depressive symptomatology and, to a greater extent, family characteristics showed high levels of stability over the 1-year period. Counter to our expectations, the relations between family variable and depressive symptomatology were similar for boys and girls. The results suggest that the quality of family interactions is relevant for understanding the development of depressive symptoms in adolescents.

Effect of practice guidelines on therapeutic bed use

Therapeutic beds, though clinically beneficial, can prove to be costly if their use is not directed. In this research utilization project, the use of therapeutic beds in five patient care units and one intensive care unit in a 300-bed acute care hospital were evaluated before and after the implementation of practice guidelines. Usage time and cost for each patient were measured and compared over the same four-month period in 1994 and 1995. Our findings indicated there were no significant differences between the two groups with regard to the time patients spent on therapeutic beds and the total cost of these beds. The mean time on the bed and the mean cost per patient were, however, lower for the practice guideline group. It was concluded that even without demonstrating significant differences, practice guidelines are a useful tool in providing a standard for nursing practice when caring for patients in the acute care setting.

Prevention of an increase in plasma cortisol during hypoglycemia preserves subsequent counterregulatory responses

The aim of this study was to determine whether preventing increases in plasma cortisol during antecedent hypoglycemia preserves autonomic nervous system counterregulatory responses during subsequent hypoglycemia. Experiments were carried out on 15 (8 male/7 female) healthy, overnight-fasted subjects and 8 (4 male/4 female) age- and weight-matched patients with primary adrenocortical failure. 5 d before a study, patients had their usual glucocorticoid therapy replaced with a continuous subcutaneous infusion of cortisol programmed to produce normal daily circadian levels. Both groups underwent identical 2-d experiments. On day 1, insulin was infused at a rate of 1.5 mU/kg per min, and 2-h clamped hypoglycemia (53+/-2 mg/dl) was obtained during the morning and afternoon. The next morning, subjects underwent an additional 2-h hypoglycemic (53+/-2 mg/ dl) hyperinsulinemic clamp. In controls, day 2 steady state epinephrine, norepinephrine, pancreatic polypeptide, glucagon, growth hormone, and muscle sympathetic nerve activity were significantly blunted (P < 0.01) compared with day 1 hypoglycemia. In marked contrast, when increases of plasma cortisol were prevented in the patient group, day 2 neuroendocrine, muscle sympathetic nerve activity, hypoglycemic symptoms, and metabolic counterregulatory responses were equivalent with day 1 results. We conclude that (a) prevention of increases of cortisol during antecedent hypoglycemia preserves many critical autonomic nervous system counterregulatory responses to subsequent hypoglycemia; (b) hypoglycemia-induced increases in plasma cortisol levels are a major mechanism responsible for causing subsequent hypoglycemic counterregulatory failure; and (c) our results suggest that other mechanisms, apart from cortisol, do not play a major role in causing hypoglycemia-associated autonomic failure.

Hydrogen exchange in chymotrypsin inhibitor 2 probed by mutagenesis

Two-dimensional NMR spectroscopy has been used to monitor hydrogen-deuterium exchange in chymotrypsin inhibitor 2. Application of two independent tests has shown that at pH 5.3 to 6.8 and 33 to 37 degrees C, exchange occurs via an EX2 limit. Comparison of the exchange rates of a number of mutants of CI2 with those of wild-type identifies the pathway of exchange, whether by local breathing, global unfolding or a mixture of the two pathways. For a large number of residues, the exchange rates were unaffected by mutations which destabilized the protein by up to 1.9 kcal mol(-1), indicating that exchange is occurring through local fluctuations of the native state. A small number of residues were found for which the mutations had the same effect on the rate constants for exchange as on the equilibrium constant for unfolding, indicating that these residues exchange by global unfolding. These are residues that have the slowest exchange rates in the wild-type protein. We see no correspondence between these residues and residues involved in the nucleation site for the folding reaction identified by protein engineering studies. Rather, the exchange behaviour of CI2 is determined by the native structure: the most protected amide protons are located in regions of hydrogen bonding, specifically the C terminus of the alpha-helix and the centre of the beta-sheet. A number of the most slowly exchanging residues are in the hydrophobic core of the protein.