Impact of accreditation on documentation and staff perception in the ophthalmology department of an Indian medical college

Purpose

National Accreditation Board for Hospitals and Healthcare Providers operates the health-care accreditation program in India. Research on impact of accreditation on eye-care centers is scarce. This article was conceptualized to scientifically evaluate the changes in documentation brought about by accreditation and its effects on staff in the Ophthalmology Department of an Indian Medical College.

Methods

This was conducted as a quasi-experimental study in four steps. First, a point-based evaluation of case sheets in both pre-accreditation and postaccreditation phase, along with statistical analysis of the results, was done. Step two involved analysis of quality indicators and patient safety indices in successive years from inception of data to post-accreditation phase. Step three comprised a survey of staff employing a validated tool, and finally, face-to-face semistructured interviews with designated authorities, including finance departmental head, completed the study.

Results

A statistically significant difference was seen in scores achieved by the pre and postaccreditation case sheets, with the postphase case sheets achieving 15% increased scores over the prephase case sheets. Quality indicator indices displayed improvements post-accreditation. There was an accompanying increase in quantity of documentation. Financial data analysis showed increased expenditure for accreditation under multiple heads. Staff believed that accreditation led to increased workload but did not express decreased satisfaction and felt that accreditation was eventually beneficial. However, staff believed rewards for improving quality can be enhanced.

Conclusion

Accreditation increases quality and quantity of documentation, and staff workload. Increased financial costs also ensue.Staff believe that accreditation improves quality, is beneficial, but desire enhanced rewards.

Infectious complications and mortality in an American acute care surgical service

BACKGROUND

Acute care surgery (ACS) services have evolved in an effort to provide 24-h surgical services for a wide array of general surgical emergencies. The formation of ACS services has been shown to improve outcomes and lead to more expeditious care. Despite the advances of ACS, the etiology and timing of patient mortality has yet to be described. We hypothesized that infectious complications occur more frequently in ACS patients that die during their hospitalization.

METHODS

A retrospective review of a local ACS service (non-trauma) registry was conducted. Demographic variables, admission and discharge data, and ICD-9 codes were collected. ICD-9 codes were used to identify patients with sepsis, shock, GI perforation, peritonitis, and other hospital acquired infections (urinary tract, bloodstream, and ventilator-associated pneumonias). Univariate and multivariate logistic regression analysis was performed to model the outcome of death.

RESULTS

1,329 patients were analyzed. 53 % were male with the mean age of 52 years and an average length of stay of 13 days. 106 (8 %) died while in the hospital. Of the patients who died, 34 (32 %) died within 7 days of admission. The majority of mortalities (56 %) occurred after hospital day 14. In ACS patients that died, there were significantly higher rates of sepsis, shock, peritonitis, urinary tract infections, and VAP. After adjustment; age, sepsis on admission, and shock on admission were associated with greater odds of death.

CONCLUSION

ACS patients with sepsis and shock have higher mortality rate than those patients without. The majority of ACS patient deaths occurred after hospital day 14. Further investigation and continued focus on preventing and rapidly treating infectious complications as they arise is warranted.

Risperidone and weight change in children with learning disability. A retrospective study

Aim

Risperidone has been recommended for the management of disruptive behaviour disorders in children with learning disabilities. This study explored the effects of Risperidone on absolute body weight in children with learning disabilities who received Risperidone for disruptive behaviour disorders.

Methodology

Data was collected for children (n = 70) with learning disabilities who were prescribed Risperidone for disruptive behaviour disorders in out patient clinic. Weight, height and BMI were recorded at the first appointment and at the follow up for up to one year. Data was analysed to find any changes in weight and BMI during the course of treatment with Risperidone.

Results

Mean weight gain for the sample was 6.1 kg (sd = 2.7), 1.7 kg more than expected in one year which was statistically significant (t = 6.2, df = 69, p < 0.001). Mean BMI change was 1.51 kg; significantly larger than the mean expected BMI change of 0.62 of this sample (t = 4.98, df = 1.6, P = 0.001). Change in BMI was more for girls, 2.17 (sd = 1.00) compared with boys 1.36 (sd = 1.18), but this was not significant (t = 1.90, df = 49, p = 0.06). There is no significant relationship between Risperidone dose and weight gain (Pearson's r = 0.21, p = 0.42) and BMI (Pearson's r = 0.03, p = 1.00).

Conclusion

Risperidone should be used with caution in children where weight gain could have long lasting impact. Prescribing clinicians should obtain baseline measures of weight, height, BMI and monitor them at regular intervals. Emphasis should be placed on life style interventions such as diet, physical activities etc. Further comparable studies with larger sample sizes using more homogenous diagnostic samples are needed.

Impact of an easily reducible disulfide bond on the oxidative folding rate of multi-disulfide-containing proteins

The burial of native disulfide bonds, formed within stable structure in the regeneration of multi-disulfide-containing proteins from their fully reduced states, is a key step in the folding process, as the burial greatly accelerates the oxidative folding rate of the protein by sequestering the native disulfide bonds from thiol-disulfide exchange reactions. Nevertheless, several proteins retain solvent-exposed disulfide bonds in their native structures. Here, we have examined the impact of an easily reducible native disulfide bond on the oxidative folding rate of a protein. Our studies reveal that the susceptibility of the (40-95) disulfide bond of Y92G bovine pancreatic ribonuclease A (RNase A) to reduction results in a reduced rate of oxidative regeneration, compared with wild-type RNase A. In the native state of RNase A, Tyr 92 lies atop its (40-95) disulfide bond, effectively shielding this bond from the reducing agent, thereby promoting protein oxidative regeneration. Our work sheds light on the unique contribution of a local structural element in promoting the oxidative folding of a multi-disulfide-containing protein.

Phosphorylation of two serine residues regulates human T-cell leukemia virus type 2 Rex function

The function of the human T-cell leukemia virus (HTLV) Rex phosphoprotein is to increase the level of the viral structural and enzymatic gene products expressed from the incompletely spliced viral RNAs containing the Rex-responsive element. The phosphorylation of HTLV type 2 Rex (Rex-2), predominantly on serine residues, correlates with an altered conformation, as detected by a gel mobility shift, and is required for specific binding to its viral RNA target sequence. Thus, the phosphorylation state of Rex in the infected cell may be a switch that determines whether the virus exists in a latent or a productive state. A mutational analysis of Rex-2 that focused on serine and threonine residues was performed to identify regions or domains within Rex-2 important for function, with a specific emphasis on identifying Rex-2 phosphorylation mutants. We identified mutations near the carboxy terminus that disrupted a novel region or domain and abrogated Rex-2 function. Mutant M17 (with S151A and S153A mutations) displayed reduced phosphorylation that correlated with reduced function. Replacement of both serine residues 151 and 153 with phosphomimetic aspartic acid restored Rex-2 function and locked Rex-2 in a phosphorylated active conformation. A mutant containing threonine residues at positions 151 and 153 displayed a phenotype indistinguishable from that of wild-type Rex. Furthermore, this same mutant showed increased threonine phosphorylation and decreased serine phosphorylation, providing conclusive evidence that one or both of these residues are phosphorylated in vivo. Our results provide the first direct evidence that the phosphorylation of Rex-2 is important for function. Further understanding of HTLV Rex phosphorylation will provide insight into the regulatory control of HTLV replication and ultimately the pathobiology of HTLV.

Coupling of conformational folding and disulfide-bond reactions in oxidative folding of proteins

The oxidative folding of proteins consists of conformational folding and disulfide-bond reactions. These two processes are coupled significantly in folding-coupled regeneration steps, in which a single chemical reaction (the "forward" reaction) converts a conformationally unstable precursor species into a conformationally stable, disulfide-protected successor species. Two limiting-case mechanisms for folding-coupled regeneration steps are described. In the folded-precursor mechanism, the precursor species is preferentially folded at the moment of the forward reaction. The (transient) native structure increases the effective concentrations of the reactive thiol and disulfide groups, thus favoring the forward reaction. By contrast, in the quasi-stochastic mechanism, the forward reaction occurs quasi-stochastically in an unfolded precursor; i.e., reactive groups encounter each other with a probability determined primarily by loop entropy, albeit modified by conformational biases in the unfolded state. The resulting successor species is initially unfolded, and its folding competes with backward chemical reactions to the unfolded precursors. The folded-precursor and quasi-stochastic mechanisms may be distinguished experimentally by the dependence of their kinetics on factors affecting the rates of thiol--disulfide exchange and conformational (un)folding. Experimental data and structural and biochemical arguments suggest that the quasi-stochastic mechanism is more plausible than the folded-precursor mechanism for most proteins.

Structural determinants of oxidative folding in proteins

A method for determining the kinetic fate of structured disulfide species (i.e., whether they are preferentially oxidized or reshuffle back to an unstructured disulfide species) is introduced. The method relies on the sensitivity of unstructured disulfide species to low concentrations of reducing agents. Because a structured des species that preferentially reshuffles generally first rearranges to an unstructured species, a small concentration of reduced DTT (e.g., 260 microM) suffices to distinguish on-pathway intermediates from dead-end species. We apply this method to the oxidative folding of bovine pancreatic ribonuclease A (RNase A) and show that des[40-95] and des[65-72] are productive intermediates, whereas des[26-84] and des[58-110] are metastable dead-end species that preferentially reshuffle. The key factor in determining the kinetic fate of these des species is the relative accessibility of both their thiol groups and disulfide bonds. Productive intermediates tend to be disulfide-secure, meaning that their structural fluctuations preferentially expose their thiol groups, while keeping their disulfide bonds buried. By contrast, dead-end species tend to be disulfide-insecure, in that their structural fluctuations expose their disulfide bonds in concert with their thiol groups. This distinction leads to four generic types of oxidative folding pathways. We combine these results with those of earlier studies to suggest a general three-stage model of oxidative folding of RNase A and other single-domain proteins with multiple disulfide bonds.

Oxidative folding of proteins

The oxidative folding of proteins is reviewed and illustrated with bovine pancreatic ribonuclease A (RNase A). The mutual effects of conformational folding and disulfide bond regeneration are emphasized, particularly the "locking in" of native disulfide bonds by stable tertiary structure in disulfide intermediates. Two types of structured metastable disulfide species are discerned, depending on the relative protection of their disulfide bonds and thiol groups. Four generic pathways for oxidative folding are identified and characterized.

Acceleration of oxidative folding of bovine pancreatic ribonuclease A by anion-induced stabilization and formation of structured native-like intermediates

Phosphate anions accelerate the oxidative folding of reduced bovine pancreatic ribonuclease A with dithiothreitol at several temperatures and ionic strengths. The addition of 400 mM phosphate at pH 8.1 increased the regeneration rate of native protein 2.5-fold at 15 degrees C, 3.5-fold at 25 degrees C, and 20-fold at 37 degrees C, compared to the rate in the absence of phosphate. In addition, the effects of other ions on the oxidative folding of RNase A were examined. Fluoride was found to accelerate the formation of native protein under the same oxidizing conditions. In contrast, cations of high charge density or ions with low charge density appear to have an opposite effect on the folding of RNase A. The catalysis of oxidative folding results largely from an anion-dependent stabilization and formation of tertiary structure in productive disulfide intermediates (des-species). Phosphate and fluoride also accelerate the initial equilibration of unstructured disulfide ensembles, presumably due to non-specific electrostatic and hydrogen bonding effects on the protein and solvent.

Disulfide bonds and protein folding

The applications of disulfide-bond chemistry to studies of protein folding, structure, and stability are reviewed and illustrated with bovine pancreatic ribonuclease A (RNase A). After surveying the general properties and advantages of disulfide-bond studies, we illustrate the mechanism of reductive unfolding with RNase A, and discuss its application to probing structural fluctuations in folded proteins. The oxidative folding of RNase A is then described, focusing on the role of structure formation in the regeneration of the native disulfide bonds. The development of structure and conformational order in the disulfide intermediates during oxidative folding is characterized. Partially folded disulfide species are not observed, indicating that disulfide-coupled folding is highly cooperative. Contrary to the predictions of "rugged funnel" models of protein folding, misfolded disulfide species are also not observed despite the potentially stabilizing effect of many nonnative disulfide bonds. The mechanism of regenerating the native disulfide bonds suggests an analogous scenario for conformational folding. Finally, engineered covalent cross-links may be used to assay for the association of protein segments in the folding transition state, as illustrated with RNase A.

Neuroanatomic substrates of late-life mental disorders

Advances in magnetic resonance imaging (MRI) techniques have made it possible to quantify anatomic brain abnormalities in neuropsychiatric disorders. This review focuses on controlled, quantitative MRI studies in depression, degenerative disorders, and psychosis in the elderly. Although many of the anatomic abnormalities detected are observed across disorders, the patterns of regional involvement may be more selective and disorder specific. We integrate MRI findings with relevant clinical and neurobiologic observations in an attempt to develop a cohesive model of late-life psychiatric illness. Although the model primarily alludes to the pathophysiology of late-life depression, it may have broader biologic implications for other mental disorders in the elderly.

Human T-cell leukemia virus type 2 tax mutants that selectively abrogate NFkappaB or CREB/ATF activation fail to transform primary human T cells

Human T-cell leukemia virus (HTLV) Tax protein has been implicated in the HTLV oncogenic process, primarily due to its pleiotropic effects on cellular genes involved in growth regulation and cell cycle control. To date, several approaches attempting to correlate Tax activation of the CREB/activating transcription factor (ATF) or NFkappaB/Rel transcriptional activation pathway to cellular transformation have yielded conflicting results. In this study, we use a unique HTLV-2 provirus (HTLV(c-enh)) that replicates by a Tax-independent mechanism to directly assess the role of Tax transactivation in HTLV-mediated T-lymphocyte transformation. A panel of well-characterized tax-2 mutations is utilized to correlate the respective roles of the CREB/ATF or NFkappaB/Rel signaling pathway. Our results demonstrate that viruses expressing tax-2 mutations that selectively abrogate NFkappaB/Rel or CREB/ATF activation display distinct phenotypes but ultimately fail to transform primary human T lymphocytes. One conclusion consistent with our results is that the activation of NFkappaB/Rel provides a critical proliferative signal early in the cellular transformation process, whereas CREB/ATF activation is required to promote the fully transformed state. However, complete understanding will require correlation of Tax domains important in cellular transformation to those Tax domains important in the modulation of gene transcription, cell cycle control, induction of DNA damage, and other undefined activities.

Hippocampal volume reduction in major depression

OBJECTIVE

Elevated levels of glucocorticoids in depression have been hypothesized to be associated with damage to the hippocampus, a brain area involved in learning and memory. The purpose of this study was to measure hippocampal volume in patients with depression.

METHOD

Magnetic resonance imaging was used to measure the volume of the hippocampus in 16 patients with major depression in remission and 16 case-matched nondepressed comparison subjects.

RESULTS

Patients with depression had a statistically significant 19% smaller left hippocampal volume than comparison subjects, without smaller volumes of comparison regions (amygdala, caudate, frontal lobe, and temporal lobe) or whole brain volume. The findings were significant after brain size, alcohol exposure, age, and education were controlled for.

CONCLUSIONS

These findings are consistent with smaller left hippocampal volume in depression.

Two new structured intermediates in the oxidative folding of RNase A

Two new three-disulfide intermediates have been found to be populated in the oxidative folding pathway of bovine pancreatic ribonuclease A at a low temperature (15 degrees C). These intermediates, des-[26-84] and des-[58-110], possess all but one of the four native disulfide bonds and have a stable tertiary structure, similar to the two previously observed intermediates, des-[65-72] and des-[40-95]. While the latter two des species each lack one surface-exposed disulfide bond, the newly discovered intermediates each lack one buried disulfide bond. The possible involvement of these species in the rate-determining steps during the oxidative folding of RNase A is discussed and a specific role for such species during oxidative folding is suggested.

Neural correlates of memories of childhood sexual abuse in women with and without posttraumatic stress disorder

OBJECTIVE

Childhood sexual abuse is very common in our society, but little is known about the long-term effects of abuse on brain function. The purpose of this study was to measure neural correlates of memories of childhood abuse in sexually abused women with and without the diagnosis of posttraumatic stress disorder (PTSD).

METHOD

Twenty-two women with a history of childhood sexual abuse underwent injection of [15O]H2O, followed by positron emission tomography imaging of the brain while they listened to neutral and traumatic (personalized childhood sexual abuse events) scripts. Brain blood flow during exposure to traumatic and neutral scripts was compared for sexually abused women with and without PTSD.

RESULTS

Memories of childhood sexual abuse were associated with greater increases in blood flow in portions of anterior prefrontal cortex (superior and middle frontal gyri-areas 6 and 9), posterior cingulate (area 31), and motor cortex in sexually abused women with PTSD than in sexually abused women without PTSD. Abuse memories were associated with alterations in blood flow in medial prefrontal cortex, with decreased blood flow in subcallosal gyrus (area 25), and a failure of activation in anterior cingulate (area 32). There was also decreased blood flow in right hippocampus, fusiform/inferior temporal gyrus, supramarginal gyrus, and visual association cortex in women with PTSD relative to women without PTSD.

CONCLUSIONS

These findings implicate dysfunction of medial prefrontal cortex (subcallosal gyrus and anterior cingulate), hippocampus, and visual association cortex in pathological memories of childhood abuse in women with PTSD. Increased activation in posterior cingulate and motor cortex was seen in women with PTSD. Dysfunction in these brain areas may underlie PTSD symptoms provoked by traumatic reminders in subjects with PTSD.

Fine tuning the N-terminus of a calcium binding protein: alpha-lactalbumin

The effects of amino acid substitutions in the N-terminus of bovine recombinant alpha-lactalbumin (including enzymatic removal of the N-terminal methionine and deletion of Glu-1) were studied by intrinsic fluorescence, circular dichroism (CD), and differential scanning microcalorimetry (DSC). Wild-type recombinant alpha-lactalbumin has a lower thermostability and calcium affinity compared to the native protein, while the properties of wild-type protein with the N-terminal methionine enzymatically removed are similar to the native protein. Taken together, the fluorescence, CD, and DSC results show that recombinant wild type alpha-lactalbumin in the absence of calcium ion is in a type of molten globule state. The delta-E1 mutant, where the Glu(1)residue of the native sequence is genetically removed, leaving an N-terminal methionine in its place, shows almost one order of magnitude higher affinity for calcium and higher thermostability (both in the absence and presence of calcium) than the native protein isolated from milk. It was concluded that the N-terminus of the protein dramatically affects both stability and function as manifested in calcium affinity. Proteins 1999;37:65-72.

Treatment of major depression with nortriptyline and paroxetine in patients with ischemic heart disease

OBJECTIVE

This study compared the efficacy, tolerability, and safety of paroxetine and nortriptyline in depressed patients with ischemic heart disease.

METHOD

After a 2-week, single-blind placebo lead-in phase, 81 outpatients with DSM-III-R-defined nonpsychotic unipolar major depression and ischemic heart disease were randomly assigned to double-blind treatment with paroxetine or nortriptyline for 6 weeks. Paroxetine was administered at a fixed-flexible dose of 20-30 mg/day. Nortriptyline dose was adjusted with the use of blood-level monitoring to reach a plasma concentration of 50-150 ng/ml.

RESULTS

Twenty-seven of the 41 patients who started treatment with paroxetine and 29 of the 40 patients who started treatment with nortriptyline had an improvement of at least 50% in their Hamilton Depression Rating Scale scores. Significantly more patients taking nortriptyline discontinued treatment prematurely (35% versus 10%), and more patients taking nortriptyline had adverse events resulting in termination (25% versus 5%).

CONCLUSIONS

Both treatments were efficacious. Sixty-three percent of all patients improved at least 50%, and of these, 90% met the criteria for remission. Paroxetine was better tolerated than nortriptyline and less likely to produce cardiovascular side effects.

The effects of stress on memory and the hippocampus throughout the life cycle: implications for childhood development and aging

Studies in animals showing hippocampal atrophy and associated memory deficits in stress and aging have implications for stress and aging in humans. Clinical studies in traumatized human populations with posttraumatic stress disorder (PTSD) have replicated studies in animals, showing reduction in volume of the hippocampus measured with magnetic resonance imaging and associated memory deficits. Trauma at different stages of development (early childhood abuse versus trauma in later life due to combat) may influence the nature of memory deficits and hippocampal atrophy. Studies in aging human subjects are consistent with animal studies, although future research is needed in this area. The similarities between biological findings related to cortisol and the hippocampus in stress and aging in both animal and human studies raises the question of whether PTSD can be seen as a form of accelerated aging. Evidence that stress affects the hippocampus and the capacity for learning has broad implications for public health policy, underlying the need for additional resources in this important area and a reexamination of our understanding of factors influencing academic achievement.

Divalproex treatment of mania in elderly patients

Because lithium is difficult to use, divalproex may be an effective alternative for elderly manic patients. In this study, the authors retrospectively assessed outcome of 21 patients, age 60 to 82 years, hospitalized for a manic episode and treated with divalproex. The mean final divalproex dose was 1,405 mg/day, and the mean serum level was 72 micrograms/ml; 20 patients also received concomitant neuroleptic medication. Overall, 19 of the 21 patients (90%) were rated as Much or Very Much Improved. The only remarkable side effect, sedation, occurred in two patients and improved with dose reduction. Although the study suggests that divalproex is an effective and well tolerated treatment for elderly manic patients, the retrospective nature of the study and the concomitant administration of neuroleptic medication suggest caution in interpreting the findings.

Serotonin transporter-blocking properties of nefazodone assessed by measurement of platelet serotonin

This study aims to determine whether the newly introduced serotonin type 2 (5-HT2) antagonist nefazodone has serotonin (5-HT) transporter-blocking properties at clinical doses in depressed patients. Change in platelet 5-HT was used as an index of the cumulative peripheral 5-HT uptake blockade produced by nefazodone and selective serotonin reuptake inhibitors (SSRIs). Platelet 5-HT was measured before and during treatment with nefazodone (N = 6) or an SSRI (N = 10) in patients with major depression. Corresponding Hamilton Rating Scale for Depression (HAM-D) scores were also obtained over the course of the study. The results of the study demonstrated that the decrease from mean baseline platelet 5-HT after SSRI treatment was significantly greater than the change after nefazodone treatment (-88% vs. -3%; Mann-Whitney U-test, p = 0.0002). Pretreatment platelet 5-HT level, posttreatment platelet 5-HT level, nor the percent decrease in platelet 5-HT correlated with the percent change in HAM-D scores in either treatment group. In conclusion, therapeutic doses of nefazodone do not cause sustained 5-HT uptake inhibition at the platelet 5-HT transporter.

Comparison of paroxetine and nortriptyline in depressed patients with ischemic heart disease

CONTEXT

Depression and ischemic heart disease often are comorbid conditions and, in patients who have had a myocardial infarction, the presence of depression is associated with increased mortality. Patients with heart disease need a safe and effective treatment for depression.

OBJECTIVE

To compare the efficacy, cardiovascular effects, and safety of a specific serotonin reuptake inhibitor, paroxetine, with a tricyclic antidepressant, nortriptyline hydrochloride, in depressed patients with ischemic heart disease.

DESIGN

Two-week placebo lead-in followed by a double-blind randomized 6-week medication trial.

SETTING

Research clinics in 4 university centers.

PATIENTS

Eighty-one outpatients meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for major depressive disorder and with documented ischemic heart disease.

INTERVENTIONS

Treatment with either paroxetine, 20 to 30 mg/d, or nortriptyline targeted to a therapeutic plasma level, 190 to 570 nmol/L (50-150 ng/mL), for 6 weeks.

MAIN OUTCOME MEASURES

For effectiveness of treatment, a decline in the score of the Hamilton Rating Scale for Depression by 50% and final score of 8 or less; for cardiovascular safety, heart rate and rhythm, supine and standing systolic and diastolic blood pressures, electrocardiogram conduction intervals, indexes of heart rate variability, and rate of adverse events.

RESULTS

By intent-to-treat analysis, 25 (61%) of 41 patients improved during treatment with paroxetine and 22 (55%) of 40 improved with nortriptyline. Neither drug significantly affected blood pressure or conduction intervals. Paroxetine had no sustained effects on heart rate or rhythm or indexes of heart rate variability, whereas patients treated with nortriptyline had a sustained 11% increase in heart rate from a mean of 75 to 83 beats per minute (P<.001) and a reduction in heart rate variability, as measured by the SD of all normal R-R intervals over a 24-hour period, from 112 to 96 (P<.01). Adverse cardiac events occurred in 1 (2%) of 41 patients treated with paroxetine and 7 (18%) of 40 patients treated with nortriptyline (P<.03).

CONCLUSIONS

Paroxetine and nortriptyline are effective treatments for depressed patients with ischemic heart disease. Nortriptyline treatment was associated with a significantly higher rate of serious adverse cardiac events compared with paroxetine.

Mapping fatty acid binding to beta-lactoglobulin: Ligand binding is restricted by modification of Cys 121

Native beta-lactoglobulin (Blg) binds 1 mole of palmitic acid per mole of protein with a dissociation constant of 0.6 microM for the primary fatty acid binding site. Chemical modification of Cys 121, which lies at the external putative hydrophobic binding site of Blg, does not affect retinol or 4,4'-bis 1-(phenylamino)-8-naphthalenesulfonate (bis-ANS) binding to the protein, indicating that the incorporated appendages do not perturb the internal hydrophobic site within the beta-barrel of Blg (i.e., the retinoid site is unaffected). On the other hand, methylation of Cys 121, reduces the affinity of Blg for palmitic acid by 10-fold as monitored by intrinsic fluorescence. Modification of the Cys 121 with methylmethanethiosulfonate or a thiol-specific spin label appears to either further weaken or totally eliminate fatty acid binding, respectively, due to steric hindrance. Furthermore, this binding pattern has been independently verified using a spin labeled fatty acid analog and monitoring ESR as well as by bis-ANS fluorescence when bound to the protein. These results suggest that fatty acids bind at the "external site" of beta-lactoglobulin, between the sole alpha-helix and the beta-barrel. In addition, structural stability studies of native and chemically modified Blg appear to confirm this observation as well.

Interactions of alpha-lactalbumin with fatty acids and spin label analogs

Bovine alpha-lactalbumin (alpha-LA) has been shown by intrinsic protein fluorescence and electron spin resonance methods to interact with the spin-labeled fatty acid analog, 5-doxylstearic acid, as well as stearic acid. An intrinsic fluorescence titration of various alpha-LA forms with 5-doxylstearic acid causes first an increase and then a decrease in emission intensity with concomitant shifts in tryptophan emission wavelength. In some cases, up to three steps in the fluorescence titration curves were visible, which were fit to apparent binding steps from 10(-6) to 10(-4) M. The binding parameters of 5-doxylstearic acid for apo- and Ca2+-alpha-LA were an order of magnitude different from one another; the stronger one, apo-alpha-lactalbumin, exhibited a Kd of 35 microM. Electron spin resonance titrations of 5-doxylstearic acid-loaded apo-alpha-LA with stearate (micelles) seem to suggest separate binding loci if alpha-LA indeed binds stearate at these concentrations. The titration of alpha-LA by stearic acid results in a fluorescence emission red shift and an apparent stepped increase in fluorescence intensity. Lipid-protein association occurred at concentrations at which stearic acid micelles and aggregates begin to form in the absence of protein. Nonetheless, the relatively strong association between stearic acid and apo-alpha-LA was also confirmed by means of the fluorescent indicator acrylodated fatty acid binding protein, in which addition of alpha-LA to the stearate-loaded indicator protein reverses the decrease in fluorescence of the acrylodan chromophore conjugated to the protein.

Evaluation of P-glycoprotein expression in human oral oncogenesis: correlation with clinicopathological features

To determine whether the multidrug-resistance-gene product phospho-glycoprotein (P-gp) is implicated in progression of oral tumours and/or drug resistance, the expression of P-gp was examined in different stages of oral oncogenesis using monoclonal antibody C-219. Cryosections from normal (41 cases), dysplastic lesions (32 cases), untreated primary SCCs (50 cases) and recurrent tumours (31 cases) were used for immunostaining, and the results were corroborated by immunoblotting. Chi-square test for trend analysis showed a significant increase in P-gp immunopositivity across the normal, leukoplakia, primary oral SCC and recurrent SCC groups (p < 0.01). Expression of P-gp in dysplastic lesions showed significant association with severity of dysplasia, the level of P-gp protein being higher in severe and moderate dysplasia. Among the primary tumours, significant correlation was observed between P-gp positivity as well as level of P-gp expression and tumour stage. The recurrent tumours showed significant increase in P-gp expression as compared with untreated primary oral tumours. We conclude that differential expression of P-gp may be an index of the disease prognosis in oral-cancer patients in the context of the Indian population.

Treatment of dementia with behavioral disturbance using divalproex or a combination of divalproex and a neuroleptic

BACKGROUND

Neuroleptics have been used extensively to treat noncognitive behavioral disturbances in dementia, although their efficacy is only moderate and side effects are prominent. This study aims to determine the efficacy and tolerability of the non-neuroleptic divalproex sodium in patients with dementia and behavioral problems.

METHOD

Charts of consecutive inpatients with dementia and behavioral problems according to DSM-IV were retrospectively reviewed. Patients treated with divalproex were analyzed for dosage, duration of divalproex treatment, levels, efficacy, side effects, and concurrent medications. Target behavioral symptoms were identified, and change was rated using a Clinical Global Impressions (CGI)-Severity of Illness scale. Patients who were much or very much improved were considered to be responders.

RESULTS

Twenty-five patients (15 men and 10 women) with a mean+/-SD age of 77+/-7 years were identified. Fourteen (56%) of the 25 patients met our criteria for response after the addition of divalproex. Divalproex given alone was effective in 7 of 15 patients. Divalproex was added to an ongoing neuroleptic in 10 patients, and 7 patients responded. Patients received a mean final divalproex dose of 1650 mg/day with a mean blood level of 64 microg/mL. Divalproex was well tolerated in this population except for reversible sedation in 8 patients and transient worsening gait and confusion in 1 subject.

CONCLUSION

Divalproex appeared to be as effective as previously reported rates for neuroleptics in the treatment of behavioral disturbances in dementia. The combination of divalproex and a neuroleptic was effective in patients who had failed either agent administered independently.

Biological reactions of peroxynitrite: evidence for an alternative pathway of salicylate hydroxylation

Salicylate hydroxylation has often been used as an assay of hydroxyl radical production in vivo. We have examined here if hydroxylation of salicylate might also occur by its reaction with peroxynitrite. To test this hypothesis, we exposed salicylate to various concentrations of peroxynitrite, in vitro. We observed the hydroxylation of salicylate at 37 degrees C by peroxynitrite at pH 6, 7 and 7.5, where the primary products had similar retention times on HPLC to 2,3- and 2,5-dihydroxybenzoic acid. The product yields were pH dependent with maximal amounts formed at pH 6. Furthermore, the relative concentration of 2,3- to 2,5-dihydroxybenzoic acid increased with decreasing pH. Nitration of salicylate was also observed and both nitration and hydroxylation reaction products were confirmed independently by mass spectrometry. The spin trap N-t-butyl-alpha-phenylnitrone (PBN), with or without dimethyl sulfoxide (DMSO), was incapable of trapping the peroxynitrite decomposition intermediates. Moreover, free radical adducts of the type PBN/.CH3 and PBN/.OH were susceptible to destruction by peroxynitrite (pH 7, 0.1 M phosphate buffer). These results suggest direct peroxynitrite hydroxylation of salicylate and that the presence of hydroxyl radicals is not a prerequisite for hydroxylation reactions.

Polypurine/polypyrimidine sequences as cis-acting transcriptional regulators

Genome sequence information has generated increasing evidence for the claim that repetitive DNA sequences present within and around genes could play a important role in the regulation of gene expression. Polypurine/polypyrimidine sequences [poly(Pu/Py)] have been observed in the vicinity of promoters and within the transcribed regions of many genes. To understand whether such sequences influence the level of gene expression, we constructed several prokaryotic and eukaryotic expression vectors incorporating poly(Pu/Py) repeats both within and upstream of a reporter gene, lacZ (encoding beta-galactosidase), and studied its expression in vivo. We find that, in contrast to the situation in Escherichia coli, the presence of poly(Pu/Py) sequences within the gene does not significantly inhibit gene expression in mammalian cells. On the other hand, the presence of such sequences upstream of lacZ leads to a several-fold reduction of gene expression in mammalian cells. Similar down-regulation was observed when a structural cassette containing poly(Pu/Py) sequences upstream of lacZ was integrated into yeast chromosome V. Sequence analysis of the nine totally sequenced yeast chromosomes shows that a large number of such sequences occur upstream of ORFs. On the basis of our experimental results and DNA sequence analysis, we propose that these sequences can function as cis-acting transcriptional regulators.

Fatty acids and retinoids bind independently and simultaneously to beta-lactoglobulin

beta-Lactoglobulin (Big) binds 1 mol of a fatty acid spin-label analog, 5-doxylstearic acid (5-DSA), per mole of protein with a dissociation constant Kd = 0.8 microM for the strongest binding site. There are also several weaker sites for this ligand. Blg saturated with either retinol or retinoic acid binds 5-DSA with essentially equal affinity (Kd = 0.6 and 1 microM, respectively). Palmitic acid and SDS displace bound 5-DSA from Blg. However, unlike palmitic acid, 5-DSA binding does not enhance the structural stability of Blg to urea denaturation. The spin-labeled fatty acid also binds to the protein at low pH, presumably at secondary fatty acid binding sites. These results suggest that Blg binds at least two different types of hydrophobic ligands simultaneously.

Comparison of technetium-99m-HMPAO and technetium-99m-ECD cerebral SPECT images in Alzheimer's disease

SPECT has shown increasing promise as a diagnostic tool in Alzheimer's disease (AD). Recently, a new SPECT brain perfusion agent, 99mTc-ethyl cysteinate dimer (99mTc-ECD) has emerged with purported advantages in image quality over the established tracer, 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO). This research aimed to compare cerebral images for 99mTc-HMPAO and 99mTc-ECD in discriminating patients with AD from control subjects.

METHODS

Twenty-four AD patients (mean age +/- s.d. = 68.9 +/- 8.2 yr) and 13 healthy subjects (68.4 +/- 8.0 yr) were scanned sequentially with 20 mCi of each tracer using the CERASPECT system within 1 mo. Scanning began on average 11.5 +/- 2.8 min after 99mTc-HMPAO injection and 41.8 +/- 10.1 min after 99mTc-ECD. A ratio, R, was derived of count densities in "typically affected" brain structures (parietal and temporal association cortices) to "unaffected" structures (cerebellum, basal ganglia, thalamus, occipital cortex, and sensorimotor cortex).

RESULTS

Analysis of variance revealed significant interaction between diagnostic group and radiopharmaceutical (F = 4.71; df = 1.35; p = 0.04), with 99mTc-ECD demonstrating better separation of R values between AD patients and control subjects than 99mTc-HMPAO. Receiver operating characteristic (ROC) analysis, revealed no significant difference in the ability of the two tracers to correctly classify AD patients and control subjects. Both tracers showed high diagnostic accuracy (99mTc-ECD: sensitivity = 100%, specificity = 92%; 99mTc-HMPAO: sensitivity = 100%, specificity = 85%).

CONCLUSION

Technetium-99m-ECD shows greater contrast than 99mTc-HMPAO between affected and unaffected brain structures in AD when patients are compared to age-matched control subjects. Both tracers perform equally well in correctly classifying patients and control subjects.

Plasma levels of gamma-aminobutyric acid and panic disorder

Low levels of gamma-aminobutyric acid (GABA) in plasma have been associated with the presence of mood disorders in patients with major depressive disorder. We examined plasma GABA in patients with panic disorder, a disorder that is often comorbid with major depression, and in a group of control subjects. Patients with panic disorder had plasma GABA levels that did not differ significantly from levels in controls subjects. These data support the specificity of low plasma GABA as a marker for mood disorders.

Cerebrospinal fluid levels of homovanillic acid and 5-hydroxyindoleacetic acid in autism

Cerebrospinal fluid (CSF) concentrations of the serotonin and dopamine metabolites, 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA), respectively, were measured in a group of 17 children with Autistic Disorder (DSM-III-R). The group means observed for 5HIAA (135 +/- 91 nmol/L) and HVA (502 +/- 324 nmol/L) in the autistic children were not significantly different from those seen in the control group of 15 nonneurologically impaired children (5HIAA, 122 +/- 120 nmol/L; HVA 401 +/- 378 nmol/L). These data suggest that consistent, marked alterations in central serotonin and dopamine turnover are not present in the autistic subjects studied. Although studies to date have found little or no alteration in CSF 5-HIAA in autism, the various reports of CSF HVA are not entirely congruent. Although this study is consistent with most previous studies in not finding a group difference in CSF HVA, the possibility of increased CSF HVA in autism cannot be ruled out.

Nerve conduction impairment in patients with respiratory insufficiency and severe chronic hypoxemia

Sixteen patients with chronic respiratory insufficiency and severe hypoxemia were studied to determine the effect of chronic respiratory insufficiency on peripheral sensory and motor nerve conduction. When matched with a control group, a statistically significant slowing (from p less than 0.02 to p less than 0.001) of nerve conduction was noted in the motor median, ulnar peroneal, and tibial nerves and also in the sensory median nerve. The peripheral neuropathy was probably due to chronic hypoxemia.