Readmissions to an alternate hospital in patients undergoing vascular intervention for claudication and critical limb ischemia associated with significantly higher mortality

BACKGROUND

Hospital readmissions with 30 days after vascular surgical interventions have been associated with increased morbidity, mortality, and cost. Readmission rates, now a Centers for Medicare and Medicaid Services quality measure, have been studied in databases that have excluded certain payer types and states and have not accounted for readmission to a hospital different from that of the index admission. More accurate and nationally representative data are needed, because this fragmentation of care could lead to flawed conclusions. The purpose of the present study was to examine the incidence and risk factors for readmission to a nonindex hospital for patients admitted for claudication or critical limb ischemia (CLI). We also examined how this disruption of patient care affects mortality.

METHODS

The 2013 to 2014 Nationwide Readmissions Database was queried for all patients admitted for claudication or CLI who had undergone angioplasty, lower extremity bypass, or aortobifemoral bypass. The outcomes of interest were 30- and 365-day readmission rates to any hospital, 30- and 365-day readmission rates to a nonindex hospital, and mortality rates. Multivariable logistic regression was used to identify risk factors for readmission to a nonindex hospital. The most common readmission diagnoses and diagnosis-related groups were identified.

RESULTS

A total of 92,769 patients had been admitted with peripheral vascular disease (33,055 with claudication and 59,714 with CLI). The 30- and 365-day readmission rate was 8.97% and 21.49% and 19.26% and 40.36%, for claudication and CLI, respectively. Of the 30- and 365-day readmissions, 20.47% and 24.92% had occurred at a nonindex hospital, respectively. Significantly higher mortality rates were found for patients with 30- or 365-day readmissions to different hospitals (odds ratio, 1.4 and 1.8, respectively). Multivariable analysis revealed that procedural indication and angioplasty are not significant risk factors for readmission to a different hospital. However, female sex, length of stay >7 days, and Charlson Comorbidity Index >3 remained significant risk factors for nonindex readmissions. The most common disease groups for nonindex readmission were "septicemia and disseminated infections" (6.5%), "heart failure" (6.4%), "other vascular procedures" (6.1%), and "amputation of lower limb except toes" (4.0%).

CONCLUSIONS

Previously unreported, ≥1 in 4 readmissions after lower extremity vascular procedures for peripheral vascular disease will occur at a nonindex hospital. This fragmentation of care is associated with increased mortality and has serious implications for guiding outcome and quality measures. With a sizeable portion of patients missed by current metrics, concern exists that providers are using flawed data. Further study into social- and patient-specific risk factors might provide methods to prevent these readmissions and improve outcomes in this difficult patient population.

Reduced genetic diversity in endemic Brazilian Lymania spp (Bromeliaceae) populations and implications for conservation

We analyzed the genetic diversity of populations of two sympatric species of Lymania (Bromeliaceae), both endemic to the Atlantic rainforest of southern Bahia (Brazil). Lymania azurea has a restricted occurrence, while Lymania smithii has a wider distribution. Our aim was to provide genetic data to contribute to the design of more efficient conservation strategies for these bromeliads, possibly justifying inclusion in the official Brazilian list of Endangered Species. Up to now, L. azurea has been classified by the Brazilian Ministry of the Environment as "data deficient". We sampled four populations of L. azurea throughout its distribution area in southern Bahia and two populations of L. smithii in the same region. Genotyping was performed with 48 random amplified polymorphic DNA markers. Based on the Jaccard genetic similarity index, L. smithii has greater diversity than L. azurea. An analysis of molecular variation showed greater genetic variance within than between populations for both species. L. azurea was found to have 20% inbreeding, probably due to population fragmentation, with L. smithii showing only 10%. When we analyzed pairs of populations of L. azurea within a conservation unit, we found low population structure (ФST = 0.098), apparently due to a large degree of gene flow between them. In disturbed areas, we found a higher ФST (0.372). We found low genetic variability for L. azurea, probably as a consequence of habitat fragmentation, supporting the need for its inclusion in the Brazilian list of endangered flora.

Genetic assessment of the Atlantic Forest bristle porcupine, Chaetomys subspinosus (Rodentia: Erethizontidae), an endemic species threatened with extinction

The bristle-spined porcupine, Chaetomys subspinosus, an endemic rodent from Atlantic Forest, was considered to be abundant in the recent past, but population reductions due to habitat loss and expansion of human activities caused this species to be included in the "vulnerable" category of the World Conservation Union Red List. We performed the first genetic assessment in natural populations of this focal species along its geographical distribution. Thirty-five non-invasive samples (hair) were collected from three natural populations in the Brazilian States of Sergipe, Bahia and Espírito Santo. Genetic similarity obtained by Jaccard's index, based on dominant RAPD and ISSR markers, varied between 25 and 100%. Four clusters, mainly coincident with the geographical distribution of the populations, were observed. Analysis of molecular variance based on 47 polymorphic loci showed that there was 15.99% genetic variability among populations and 84.01% within populations. The estimated genetic structure among populations (Φ(ST)) was 0.16. The populations may have formed a continuum along the past distribution of the Atlantic rainforest but historical events of human occupation resulted in recent divergence among sampled populations.

DNA extraction from bristles and quills of Chaetomys subspinosus (Rodentia: Erethizontidae) using a novel protocol

DNA extraction protocols are as varied as DNA sources. When it comes to endangered species, it is especially important to pay attention to all details that ensure the completion of the study goals and effectiveness in attaining useful data for conservation. Chaetomys subspinosus (Rodentia: Erethizontidae) is a secretive arboreal porcupine endemic to certain ecosystems of the Brazilian Atlantic Forest. A multidisciplinary study (including genetic data) was performed to create a management plan for the conservation of this species. Individuals from natural populations of the states of Bahia, Espírito Santo and Sergipe were sampled. To obtain a reliable and abundant amount of starting material, non-destructive methods were tested, extracting DNA from the bristles and quills that comprise most of this animal's hide. This method has also been innovative in adapting a DNA extraction protocol traditionally used for plants. Digestion using proteinase K was followed by protein precipitation with CTAB, a chloroform-isoamyl alcohol cleaning and DNA precipitation with isopropyl alcohol. This protocol supplies good-quality DNA for genetic analysis with molecular markers based on PCR.

Polyglutamine-expanded ataxin-7 antagonizes CRX function and induces cone-rod dystrophy in a mouse model of SCA7

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant disorder caused by a CAG repeat expansion. To determine the mechanism of neurotoxicity, we produced transgenic mice and observed a cone-rod dystrophy. Nuclear inclusions were present, suggesting that the disease pathway involves the nucleus. When yeast two-hybrid assays indicated that cone-rod homeobox protein (CRX) interacts with ataxin-7, we performed further studies to assess this interaction. We found that ataxin-7 and CRX colocalize and coimmunoprecipitate. We observed that polyglutamine-expanded ataxin-7 can dramatically suppress CRX transactivation. In SCA7 transgenic mice, electrophoretic mobility shift assays indicated reduced CRX binding activity, while RT-PCR analysis detected reductions in CRX-regulated genes. Our results suggest that CRX transcription interference accounts for the retinal degeneration in SCA7 and thus may provide an explanation for how cell-type specificity is achieved in this polyglutamine repeat disease.

Genomic organization, chromosome location, and expression analysis of mouse beta-synuclein, a candidate for involvement in neurodegeneration

The synuclein family of proteins is a group of primarily brain-expressed polypeptides that show a high degree of amino acid conservation. alpha-Synuclein is the best known of the synuclein family, as it is a major component of the Lewy body, a cytoplasmic inclusion characteristic of Parkinson's disease as well as a variety of related neurodegenerative disorders. With the discovery that mutations in alpha-synuclein can cause Parkinson's disease, a potential role for the other synuclein family members in neurodegenerative disease is being considered. beta-Synuclein in particular may deserve special attention, as it is co-expressed with alpha-synuclein at presynaptic nerve terminals, is subject to phosphorylation by Ca(2+) calmodulin protein kinase II, appears important for neural plasticity, and forms aggregates in the brains of patients with Parkinson's disease and a related disorder. To facilitate study of beta-synuclein, we have cloned the mouse beta-synuclein gene (Sncb) and determined its genomic organization, size, and intron-exon structure. Using an interspecific backcross mapping panel from The Jackson Laboratory, we were then able to localize Sncb to chromosome 13 at the MGD 35.0 cM position. Like the human beta-synuclein gene, Sncb appears to consist of six exons separated by five introns. Unlike the human beta-synuclein gene, the mouse ortholog possesses a variant GC 5' splice donor sequence at the exon 4 - intron 4 boundary in a highly conserved splice junction consensus. Northern blot analysis and Western blot analysis both indicate that Sncb is highly expressed in the brain. Knowledge of the genomic organization and expression pattern of Sncb will allow functional studies of its potential role in neurodegeneration to commence in the mouse.

A high-resolution radiation hybrid map of the human genome draft sequence

We have constructed a physical map of the human genome by using a panel of 90 whole-genome radiation hybrids (the TNG panel) in conjunction with 40,322 sequence-tagged sites (STSs) derived from random genomic sequences as well as expressed sequences. Of 36,678 STSs on the TNG radiation hybrid map, only 3604 (9.8%) were absent from the unassembled draft sequence of the human genome. Of 20,030 STSs ordered on the TNG map as well as the assembled human genome draft sequence and the Celera assembled human genome sequence, 36% of the STSs had a discrepant order between the working draft sequence and the Celera sequence. The TNG map order was identical to one of the two sequence orders in 60% of these discrepant cases.

Late-onset SCA2: 33 CAG repeats are sufficient to cause disease

SCA-2 is an autosomal dominant inherited disorder characterized by ataxia, slow saccades, and hyporeflexia. The authors evaluated a patient with a mild balance problem with a SCA-2 allele sized at 33 CAG repeats. The authors then ascertained her 91 year-old mother, who showed disease onset at age 86 with an SCA-2 allele of identical size. Their study indicates that 33 CAG repeats can be pathogenic at the SCA-2 locus, though such an allele may produce an extremely late onset and gradual rate of disease progression.

Low incidence of persistent tardive dyskinesia in elderly patients with dementia treated with risperidone

OBJECTIVE

The authors studied the incidence of tardive dyskinesia in elderly institutionalized patients with dementia being treated with risperidone.

METHOD

After participating in a 12-week multicenter double-blind study during which they received placebo or one of three doses of risperidone, 330 patients (mean age=82.5 years) with Alzheimer's, vascular, or mixed dementia were enrolled in a 1-year open-label study during which they received flexible doses of risperidone. Persistent emergent tardive dyskinesia was defined according to scores on the dyskinesia subscale of the Extrapyramidal Symptom Rating Scale.

RESULTS

The mean modal risperidone dose was 0.96 mg/day (SD=0.53), and the median length of risperidone use was 273 days. The 1-year cumulative incidence of persistent emergent tardive dyskinesia among the 255 patients without dyskinesia at baseline was 2.6%. Patients with dyskinetic symptoms at baseline experienced significant reductions in the severity of dyskinesia. Patients who received 0.75-1.5 mg/day of risperidone showed a significant improvement in psychopathologic symptoms over the 1-year period.

CONCLUSIONS

Although there was no control group, the observed incidence of persistent tardive dyskinesia with risperidone seemed to be much lower than that seen in elderly patients treated with conventional neuroleptics. The average optimal dose of risperidone in elderly dementia patients was found to be 0.75-1.5 mg/day.

Relationship between physical and psychosocial dysfunction in Mexican patients with vertigo: a cross-cultural validation of the vertigo symptom scale

The Vertigo Symptom Scale (VSS) was designed to assess and differentiate symptoms of: (a) balance disorder; and (b) somatic anxiety and autonomic arousal in patients complaining of dizziness and vertigo. Although it has been translated for use in countries other than the UK, where it was originally developed, its validity in different languages and cultures has not previously been evaluated. This study examined the structure, reliability, and discriminative power of a Spanish translation of the VSS administered to a Mexican sample of 172 dizzy patients and 40 healthy controls. Scores on the two subscales of the VSS not only discriminated between patients and controls, but were also sensitive to differences between patient groups classified on the basis of diagnosis, test results, and occupational disability. The pattern of intercorrelations between symptoms, anxiety, depression, and handicap in the Mexican sample was almost identical to that observed in the original UK sample.

A randomized, open-label comparison of venlafaxine and fluoxetine in depressed outpatients

In this randomized, open-label, 8-week comparative study, the efficacy and safety of venlafaxine and fluoxetine were assessed in outpatients with major depression. One hundred forty-five patients were assigned to receive venlafaxine 37.5 mg twice daily or fluoxetine 20 mg once daily. On day 15, if clinically indicated to improve patient response, the dosage could be increased at the investigator's discretion to venlafaxine 75 mg twice daily or fluoxetine 40 mg once daily. One hundred forty-five patients were evaluated for safety and 110, for efficacy. The mean age was 37 years, and 70% of the patients were female. In both treatment groups, mean scores on the Hamilton Depression Rating Scale decreased significantly between baseline (27.8, venlafaxine; 29.2, fluoxetine) and the end of the study (8.7, venlafaxine; 8.2, fluoxetine). Similarly, mean scores on the Montgomery-Asberg Depression Rating Scale decreased significantly between baseline (31.4, venlafaxine; 31.6, fluoxetine) and the end of the study (8.3, venlafaxine; 7.6, fluoxetine). In venlafaxine patients, the most common adverse events were nausea (44.3%), headache (40.0%), insomnia (31.4%), dizziness (30.0%), and dry mouth (22.9%); in fluoxetine patients, they were headache (32.0%), nausea (28.0%), insomnia (24.0%), anxiety (21.3%), sleepiness (20.0%), and generalized tremor (20.0%). The results of this study indicate that venlafaxine is effective and well tolerated for the treatment of major depression at doses of 37.5 or 75 mg twice daily and not significantly different from fluoxetine 20 or 40 mg once daily.

National Institute of Mental Health: an update on women and minorities in research

Guidelines for the recruitment and retention of women and minorities as subjects in clinical trials have been developed at the National Institutes of Health. Training more women and minority investigators is also a National Institutes of Health priority. These individuals, like all other applicants, however, must be sophisticated consumers of the federal grants process. This article present information about administration changes for entry-level research awards to help potential applicants understand the funding process.

National Medical Association/National Institutes of Health Workshop on Violence and the Conduct of Research. Workgroup Proceedings, June 1-2, 1994

The physical, economic, and mental toll caused by violence in the United States has put tremendous pressure on American medical, political, religious, and social institutions. The impact in urban neighborhoods has been especially harrowing, forcing African-American organizations to address this domestic problem with ideas and suggestions unique to their philosophies and collective talents. This article contains general perspectives and commentary from physicians and social science experts who participated in a workshop sponsored by the National Medical Association, the National Institute of Drug Abuse, and the National Institute of Mental Health to discuss topics on violence, its health consequences, and the conduct of research in the African-American community.

Familial alcoholism and ERPs: differences in probability sensitivity?

Event-related potentials (ERPs) were recorded from sons (age 11-14) of families that were positive (FH+) and negative (FH-) for alcoholism in response to circles, triangles and squares presented in four colors with a single central digit. A button was pressed for successive presentations of identical stimuli (target probability = 0.2). Reduced late positivity in FH+ boys has been previously reported. This positivity was shown to increase with the number of features that match target requirements. FH- boys responded more quickly, but no less accurately, than FH- boys, and were characterized by reduced ERP stimulus selectivity. That is, FH+ boys not only produced less P3 than FH- boys in response to targets, but generally produced more late positivity than FH- boys in response to nontargets. The pattern of group differences was most consistent with FH+ boys exhibiting both reduced ERP effects of target features in general, and a specific insensitivity to matching digits. It is hypothesized that these effects result from reduced sensitivity to information about the frequency with which categories of events occur, and that this may be characteristic of those at high risk for alcoholism.

Autonomic dysfunction in patients with dementia of the Alzheimer type

Abnormalities of the noradrenergic system have been documented in the central nervous system of patients with dementia of the Alzheimer's type (DAT). To evaluate the autonomic sympathetic system in DAT, we measured lying and standing blood pressure (BP), pulse, and plasma epinephrine (E) and norepinephrine (NE) in 60 DAT patients (mean age +/- SD = 65 +/- 8 years), and 20 normal elderly controls. DAT patients had normal baseline findings (BP, pulse, NE, and E). Upon standing, plasma NE and E significantly increased in both DAT patients and controls, without group differences. However, the systolic BP response to standing was reduced in DAT patients compared with the normal controls (repeated measures ANOVA, p < 0.01). This impaired response of the systolic BP on standing was particularly evident in DAT patients with symptoms of depression. Severely impaired DAT patients did not differ in E, NE, BP, pulse, or in orthostatic changes from mild-to-moderately impaired patients. These results suggest that the sympathetic response to the stress of standing is functionally impaired in DAT. This deficit was especially evident when DAT was accompanied by depression, consistent with prior studies in non-demented depressed patients.

CSF somatostatin in Alzheimer's disease and major depression: relationship to hypothalamic-pituitary-adrenal axis and clinical measures

Patients with Alzheimer's disease (AD) and major depression have been shown to have overlapping clinical symptoms and biological markers, including decreased concentrations of cerebrospinal fluid (CSF) somatostatin-like immunoreactivity (SLI), which may be related to alterations in the hypothalamic-pituitary-adrenal axis activity. As in prior studies, we found that CSF SLI was significantly decreased in a group of AD patients (N = 49) and a group of elderly patients with major depression (N = 18), as compared with 13 age-matched controls (F[2, 77] = 12.9, p < .001). In the present study, CSF SLI and CSF corticotropin-releasing factor correlated significantly within the group of AD patients (r = 0.49, p < .0004) and almost attained significance in the depressed patients (r = 0.47, p < .07). CSF SLI correlated significantly with urinary free cortisol within each patient group (r = -0.51, p < .03). Clinical measures of dementia severity and depression did not consistently correlate with CSF SLI in either patient group.

Increased cognitive sensitivity to scopolamine with age and a perspective on the scopolamine model

18 older normal volunteers (mean age = 66.5 +/- 7.9 years) and 46 younger volunteers (mean age = 27.0 +/- 6.1 years) were administered the anticholinergic drug scopolamine (0.5 mg i.v.) followed by a battery of cognitive tests evaluating attention, learning and memory. The older subjects were significantly more impaired than the younger by scopolamine on some tests of learning and memory. This increased sensitivity of the older group to scopolamine is consistent with studies in animals and humans showing decreased cholinergic system function with age. The findings also indicate that age is an important variable to consider in using the scopolamine model of memory impairment. The cognitive impairment caused by scopolamine in younger subjects in this and prior studies is similar to some, but not all aspects of the impairment which occurs in normal aging. Scopolamine also caused impairments on digit span and word fluency tasks, which are not consistent with normal aging changes. In the older group of subjects, scopolamine produced aspects of the cognitive impairment which occurs in AD on tests of episodic memory and learning, vigilance-attention, category retrieval, digit span, and number of intrusions. Other areas of cognition that are of relevance to aging and AD such as psychomotor speed, praxis, concept formation and remote memory were not evaluated in this study. Some of these are being evaluated in ongoing studies, along with additional and more specific tests of retrieval from knowledge memory, implicit memory and attention. The scopolamine model has provided a fruitful pharmacologic starting point for the study of a number of cognitive operations. The idea of dissecting apart aspects of memory systems pharmacologically depends on the availability of neurochemically specific drugs and on the specificity and sensitivity of neuropsychological tests for distinct cognitive operations or domains. Further studies using such tools will aid not only in the understanding of the impairments which occur in aging and in AD, but also of the conceptualization of memory and other cognitive operations and ultimately the physiological mechanisms involved in memory and learning.

Lack of seasonal variation in the births of patients with dementia of the Alzheimer type

Seasonal variation in the birth rates of patients suffering from dementia of the Alzheimer type (DAT) was investigated in 150 patients, aged 42-88 years, and in 132 normal control subjects of comparable age and gender. No seasonal variation or cyclic trend could be demonstrated in the DAT patients compared with control subjects. The exclusion from the analysis of the patients with a positive family history did not change the results of the study, which further suggests that a seasonality in DAT birth rates is unlikely.

Reduced cerebrospinal fluid dynorphin A1-8 in Alzheimer's disease

Cerebrospinal fluid (CSF) measures of dynorphin A were compared in three groups. Alzheimer patients (n = 9), elderly depressives (n = 9), and age-matched normal controls (n = 9). The Alzheimer patients revealed a 40% decrease in CSF dynorphin compared with controls (36 +/- 15 versus 60 +/- 21 pg/ml, p less than 0.05). In contrast, other peptide measures [Neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and galanin] remained unchanged across groups. This finding was further supported when an additional 20 Alzheimer patients with similar clinical backgrounds also showed reduced CSF dynorphin (37 +/- 13 pg/ml). CSF dynorphin did not correlate significantly with clinical variables or other CSF measures of monoamine metabolites [i.e., 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA)]. Given the previous report of increased kappa binding of Alzheimer brains at autopsy, the authors speculate about a possible up-regulation of opiate receptors in Alzheimer's disease and suggest ways to test this hypothesis in vivo.

CSF monoamine metabolites and somatostatin in Alzheimer's disease and major depression

Decreased cerebrospinal fluid (CSF), somatostatinlike immunoreactivity (SLI) and alterations in the CSF monamine metabolites 3-methoxy-4-hydroxyphenylethylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and homovanillic acid (HVA) have been reported in patients with probable Alzheimer's disease (AD) and in patients with major depression. In this study, we found CSF SLI to be significantly lower in a large group of AD patients (n = 60) and in a group of age-matched patients with major depression (n = 18) as compared with normal controls (n = 12). Mean CSF, MHPG, 5-HIAA, and HVA levels were not significantly different among diagnostic groups. Within a group of "depressed" AD patients, CSF levels of 5-HIAA showed a significant positive correlation (p = 0.03) with CSF SLI; a similar relationship was found within the group of patients with major depression. Further exploration of the relationship between the somatostatin and serotonin systems may provide clues as to how neuropeptides interact with monoamine neurotransmitters and what role they have in depression.

Reflections of the self: atypical misidentification and delusional syndromes in two patients with Alzheimer's disease

Two patients with moderately severe AD, when asked directly, could identify their own images in a mirror, but also consistently misidentified their own reflections as that of another person. Both patients were paranoid and mildly depressed at times, but had no evidence of other concurrent psychotic symptoms. It appeared that mood substantially modified the nature of the symptom and the patients' reaction to it over time. These cases illustrate the ability of an organic symptom to be modified by a concurrent affective state, indicating the importance of the interaction between biological and psychological factors in the expression of such symptoms.

Independent effects of morphine and apomorphine on stereotyped gnawing in the hamster

Eight experiments were conducted to investigate the effects of apomorphine, a dopaminergic agonist, and of morphine, an opiate, on stereotyped behavior in the hamster. Animals were observed at two minute intervals for one hour and incidents of stereotyped gnawing, licking and sniffing were recorded using a time-sampling method. Both morphine and apomorphine produced dose-related increases in stereotyped gnawing. A low dose of the opiate antagonist, naloxone (0.4 mg/kg), blocked morphine-induced gnawing but neither that dose nor higher doses of naloxone (1, 4 and 10 mg/kg) blocked apomorphine-induced gnawing. A low dose of the dopaminergic antagonist, haloperidol (0.05 mg/kg), blocked apomorphine-induced gnawing but did not block morphine-induced gnawing. Further experiments indicated that morphine administration did not sensitize, or influence in any way, subsequent apomorphine-induced stereotyped behavior.

Antigenic relationships of fractionated western diamondback rattlesnake (Crotalus atrox) hemorrhagic toxins and other rattlesnake venoms as indicated by monoclonal antibodies

Seven hemorrhagic factors have been isolated from Crotalus atrox venom, but their antigenic relationships have not been well studied. In this study, two different monoclonal antibodies, C. atrox peak 8 (CA-P-8) and C. atrox subclone 5 (CA-5+), were produced against two C. atrox venom hemorrhagic fractions and used in an ELISA (enzyme-linked immunosorbent assay) to determine if the hemorrhagic factors in C. atrox venom are antigenically related. The same ELISA test was used to determine cross-reactivity of seven other crude Crotalidae venoms. The two monoclonal antibodies were tested for their ability to neutralize each hemorrhagic HPLC fraction separated from C. atrox venom. C. atrox venom was fractionated into 22 fractions using HPLC analytical DEAE ion exchange. Fractions 4-17 were hemorrhagic. The CA-P-8 monoclonal antibody reacted strongly with hemorrhagic fraction 8; CA-5+ had a broader reactivity and reacted with several HPLC hemorrhagic and non-hemorrhagic fractions. Crude venoms of C. adamanteus, C. scutulatus scutulatus and C. viridis lutosus reacted with CA-P-8, while C. viridis lutosus, C. viridis oreganus, C. scutulatus scutulatus and C. horridus horridus reacted with CA-5+. C. molossus molossus and C. lepidus lepidus did not react with CA-P-8 and CA-5+. Hemorrhagic HPLC fractions 6, 7, 8, were completely neutralized by monoclonal antibody CA-P-8; fraction 9 was partially neutralized. The present study indicated that some C. atrox venom HPLC hemorrhagic fractions have both common and unique epitopes. Antigenic determinants were also found to be shared among different Crotalus species.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis of regiospecifically labeled [18O]glycolic acid and [18O]acyldihydroxyacetone phosphate

Methods are detailed for the preparation of [2-18O]glycolate from chloroacetic acid and for the direct conversion of these intermediates to regiospecifically labeled [2-18O]-2-O-acylglycolic acids containing approximately 90% 18O at the C-O-acyl bond. Methods are also detailed for optimization of reaction conditions and yields for each synthetic step in previously published methods for the preparation of 1-O-acyldihydroxyacetone-3-O-phosphate (DHAP) from acyloxyacetic acid (i.e., 2-O-acylglycolic acid), where acyl is tetradecanoyl, hexadecanoyl, or heptadecanoyl. The optimized reaction conditions generate 1-O-acyl DHAP in its acid form, both in high overall yield and in high purity, without requiring a final chromatographic purification of the product, 1-O-acyl DHAP. Combining these new methods, efficient and facile preparations of regiospecifically labeled [1-18O]-1-O-hexadecanoyl DHAP and [1-18O]-1-O-heptadecanoyl DHAP have now been demonstrated, in which approximately 90% 18O is specifically located only at the C-O-acyl position. Some mechanistic postulates are offered to account for the optimized yields, regioselectivities, and high 18O incorporation which are observed in the reactions we have employed to generate 1-O-acyl DHAP from glycolate intermediates.

A photoaffinity derivative of colchicine: 6'-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine. Photolabeling and location of the colchicine-binding site on the alpha-subunit of tubulin

A photoaffinity analog of colchicine, 6-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine, was synthesized by reacting deacetylcolchicine or [3H]deacetylcochicine with N-succinimidyl-6-(4'-azido-2'-nitrophenylamino)hexanoate. Homogeneity of the photoaffinity analog was established by thin-layer chromatography and high-pressure liquid chromatography. The structure of the photoaffinity analog was determined by 1H and 13C NMR, infrared and ultraviolet-visible spectroscopies, and elemental analysis. Binding of 6-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine to bovine renal tubulin was measured by competition with [3H]colchicine. The value of the apparent Ki for the photoaffinity analog was 0.28 microM in the concentration range of 0.8-1.2 microM of the analog. A value of 0.50 microM for the apparent Kd was measured by the direct binding of the tritiated photoaffinity analog to tubulin. The analog is slightly more potent an inhibitor of microtubule formation than colchicine. The photoaffinity analog reacted with renal tubulin upon irradiation with a mercury lamp equipped with a 420-nm cutoff filter. Spectral and radiochemical analyses of the tubulin after photolysis and dialysis have demonstrated a stoichiometric incorporation of the photoaffinity analog in the alpha-subunit of the tubulin. Covalent labeling of tubulin with the photoaffinity analog decreases the extent of [3H]colchicine binding by more than 90%.

Dural plasmacytoma

Dural plasmacytoma is an unusual form of myeloma. We describe a woman with plasmacytoma of the tentorium cerebelli that was managed successfully with surgical decompression and radiotherapy. Computed tomography, not previously reported in cases of dural plasmacytoma, was useful in her management. Another unique feature was the restoration of a normal immunoglobulin G content in the blood and cerebrospinal fluid after local treatment of the neoplasm. Two previously reported cases showed similar normalization of cerebrospinal fluid immunoglobulin G after local radiotherapy. Dural plasmacytoma presents a characteristic clinical syndrome. The typical patient is a woman (92% of the reported cases) in the 5th decade of life. Clinical findings reflect intracranial hypertension, often with focal neurological signs, consistent with the usual dural or tentorial origin of the tumor. Immunoglobulin abnormalities may be found in serum or cerebrospinal fluid. The prognosis is good after surgical decompression and local radiotherapy.

Synthesis of [32P]dolichyl phosphate, utilizing a general procedure for [32P]phosphorus oxychloride preparation

Equilibration of the phosphorus in radioactive phosphoric acid with the phosphorus in phosphorus oxychloride occurs if these compounds are refluxed together for approximately 24 h. This observation led us to develop a method for the preparation of radioactive phosphorus oxychloride on a small scale with high specific radioactivity. The labeled phosphorus oxychloride may be utilized directly in a one-pot reaction for the preparation of labeled phosphate esters or for the synthesis of more selective phosphorylating agents such as cyanoethyl phosphate. Since the method is very simple and capable of yielding highly labeled radioactive phosphate esters on a small scale, it is applicable to a number of different problems. The preparation of 32P-labeled dolichyl phosphate is described utilizing this procedure.