Biomedical subjects

S Spector

Publications and source records attributed to S Spector.

At least 19 recordsLinked to original sources

PubMed2004

Omalizumab: efficacy in allergic disease.

Asthma and allergic rhinitis are common conditions that have a substantial impact on patient quality of life, severely disrupting physical, emotional and social functioning. These diseases share many pathophysiological characteristics and recent research has provided evidence that a strong causal relationship exists between allergy and both asthma and allergic rhinitis. As a root cause of allergic diseases of the airways, immunoglobulin E (IgE) represents an appropriate target for the development of new therapies. Omalizumab (Xolair) is a recombinant humanized monoclonal anti-IgE antibody that has demonstrated efficacy in allergic asthma and other IgE-related allergic illnesses. In three pivotal, placebo-controlled trials in patients with moderate-to-severe allergic asthma, omalizumab provided effective disease control, significantly reducing exacerbations while improving quality of life. Additionally, omalizumab reduced the need for unscheduled outpatient visits, emergency room visits and hospitalizations. Omalizumab was particularly useful as add-on treatment for patients with poorly controlled severe asthma. Similar benefits were reported in patients with seasonal or perennial allergic rhinitis. Omalizumab significantly improved disease symptoms and reduced the use of rescue antihistamines. In patients with concomitant asthma and perennial allergic rhinitis, omaliuzumab significantly prevented asthma exacerbations and improved quality of life compared with placebo. Taken together, these results suggest that omalizumab represents an important clinical advance in the management of allergic disease.

Antibodies, Anti-Idiotypic↗

PubMed2001

Endogenous morphine and codeine. Possible role as endogenous anticonvulsants.

Exogenously administered morphine can have both convulsive or anticonvulsive effects, depending on the dose and species. The levels of the endogenous opiate alkaloids morphine and codeine were significantly elevated in specific rat brain regions by the convulsive drug, pentylenetetrazole, as well as by the anticonvulsant drugs, carbamazepine and phenytoin. Morphine and codeine levels in peripheral tissues (heart, lung, spleen and adrenal) were unaffected by these drugs. Maximal increases in morphine levels were seen in the hypothalamus and striatum (2-10-fold), while lesser increases occurred in the midbrain and brain stem (2-4-fold). Codeine levels were also markedly increased in hypothalamus (5-10 fold), In contrast to morphine, codeine levels were also increased in the hippocampus (2-10-fold), but were unchanged in the striatum. These studies suggest that the endogenous alkaloids morphine and codeine are involved in the modulation of convulsions and that morphine and/or codeine may act as an endogenous anticonvulsant.

Animals↗

PubMed2001

A controlled study of intravenous immunoglobulin combined with prednisone in the treatment of IBM.

OBJECTIVE: To investigate whether the combination of intravenous immunoglobulin (IVIg) with prednisone improves muscle strength and alters endomysial inflammation in patients with sporadic inclusion body myositis (s-IBM). BACKGROUND: In a previous controlled trial in s-IBM, IVIg did not significantly improve strength in spite of modest benefits in some muscle groups. The possibility that prednisone may have a synergistic effect with IVIg prompted another controlled trial. METHODS: Thirty-six patients with biopsy-proven IBM were randomized to receive IVIg or placebo monthly for 3 months. Before infusions, all patients were started on high-dose prednisone for 3 months. Primary outcome measures were differences in the 1) Quantitative Muscle Strength (QMT) testing; and 2) modified Medical Research Council (MRC) scores, between the patients randomized to IVIg + prednisone compared with those randomized to placebo + prednisone. Repeated open muscle biopsies were performed at random in 24 patients to determine changes in the number of autoinvasive T cells and necrotic muscle fibers. RESULTS: Nineteen patients were randomized to IVIg + prednisone and 17 to placebo + prednisone. No significant change was noted in muscle strength, assessed by QMT and MRC, from baseline to the 2nd, 3rd, or 4th month after treatment between the two groups. The number of necrotic fibers was reduced in the IVIg randomized group (p < 0.01), and the mean number of CD2+ cells was significantly decreased in both groups (p < 0.0001), denoting a steroid effect. CONCLUSION: IVIg combined with prednisone for a 3-month period was not effective in IBM. Endomysial inflammation was significantly reduced after treatment, but the reduction was not of clinical significance.

Aged↗

PubMed2001

Effects of zafirlukast upon clinical, physiologic, and inflammatory responses to natural cat allergen exposure.

BACKGROUND: Leukotriene receptor antagonists have been shown to attenuate physiologic changes in the upper and lower airways induced by allergen challenge. However, it is unknown whether these drugs modulate airway inflammation after exposure to allergen in a natural setting. OBJECTIVE: To determine the effects of the oral leukotriene receptor antagonist zafirlukast upon symptoms, changes in pulmonary function, and indices of inflammation in the upper and lower airways induced by natural exposure to cats. METHODS: Zafirlukast, 20 mg twice daily, or placebo was administered to 18 cat-allergic asthmatic patients in this randomized, double-blind, crossover study. Cat room challenges were performed after a 1-week period of each treatment. Upper and lower airway symptoms were measured and spirometry performed before and at regular intervals during each challenge. Nasal lavage and sputum induction were performed 24 hours before and after each challenge. RESULTS: Zafirlukast significantly improved the prechallenge baseline FEV1 (P = 0.001) and attenuated the decrease in FEV1 induced by cat challenge (P = 0.019). Zafirlukast also significantly reduced lower airway symptoms associated with cat challenge (P = 0.005) but had no effects on nasal symptoms. Although zafirlukast did not significantly differ from placebo in its effects on sputum inflammatory cells or eosinophil cationic protein, it significantly reduced the absolute counts of total white cells, lymphocytes, neutrophils, and basophils in nasal lavage fluid. CONCLUSIONS: Zafirlukast, 20 mg twice daily for 1 week, demonstrated a significant protective effect on symptoms of asthma and alterations in pulmonary function induced by natural cat exposure, whereas nasal symptoms and markers of sputum inflammation were not affected by the medication.

Administration, Oral↗

PubMed2001

High and low perceived self-control of epileptic seizures.

PURPOSE: To define behaviours and to identify psychological, demographic, and epilepsy-related variables associated with high as opposed to low perceived self-control of seizures. METHOD: In a semistructured interview, 100 adults with intractable seizures were asked about their seizure precipitants and attempts at self-control of seizures. They also completed four psychological questionnaires. Latent Class Analysis was used to analyse the interview data to create two groups, High Controllers and Low Controllers, who were then compared on demographic, epilepsy, and psychological characteristics. RESULTS: Being able to identify and seeking out low-risk-for-seizure situations, avoiding high-risk-for-seizure situations, and making attempts at seizure inhibition were seizure behaviours that discriminated High from Low Controllers. The general probability of being a High Controller was greater than that of being a Low Controller. Perceived high self-control of seizures was associated with low chance-health locus of control. For Low Controllers, current age, age at onset of seizures, and duration of epilepsy history were related to psychological variables. A significantly higher proportion of the Low Controllers than High Controllers were women. CONCLUSIONS: Many people with intractable seizures do not accept their epilepsy as a condition over which they have no control. Perceived self-control of seizures, however, involves a complex interaction between epilepsy and psychological factors, with health locus of control an apparently important discriminator between High and Low Controllers.

Adult↗

PubMed2001

Chest tube removal: end-inspiration or end-expiration?

BACKGROUND: Recurrent pneumothorax is the most significant complication after discontinuation of thoracostomy tubes. The primary objective of the present study was to determine which method of tube removal, at the end of inspiration or at the end of expiration, is associated with a lesser risk of developing a recurrent pneumothorax. A secondary objective was to identify potential risk factors for developing recurrence. METHODS: A prospective study of 102 chest tubes in 69 trauma patients (1.5 tubes per patient) randomly assigned to removal at the end of inspiration (n = 52) or the end of expiration (n = 50). RESULTS: Recurrent pneumothorax or enlargement of a small but stable pneumothorax was observed after the removal of four chest tubes in the end-inspiration group (8%) and after discontinuation of three chest tubes (6%) in the end-expiration group (p = 1.0). Of those, only two tubes in the end-inspiration group and 1 tube in the end-expiration group required repeat closed thoracostomy. Multiple factors were analyzed that did not adversely affect outcome. These included patient age, Injury Severity Score, Revised Trauma Score, mechanism of injury, hemothorax, thoracotomy, thoracostomy, previous lung disease, chest tube duration, the presence of more than one thoracostomy tube in the same hemithorax, or a small (but stable) pneumothorax at the time of tube removal. CONCLUSIONS: Discontinuation of chest tubes at the end of inspiration or at the end of expiration has a similar rate of post-removal pneumothorax. Both methods are equally safe.

Adolescent↗

PubMed2001

Surgical treatment of hypothalamic hamartoma and refractory seizures: a case report and review of the literature.

Refractory gelastic seizures are often associated with hypothalamic hamartoma (HH). Presurgical evaluation in such children often points to a distinct cortical region as the source of the seizures. A case of a child with HH and refractory seizures is presented. Video-EEG monitoring revealed a well-defined epileptic focus in the left frontal region. In accordance with the current understanding of the nature of hamartoma-related seizures, the hamartoma was resected. Follow-up evaluations revealed a marked improvement in seizure frequency and global functioning.

Child, Preschool↗

PubMed2000

Illumination for coherent soft X-ray applications: the new X1A beamline at the NSLS.

The X1A soft X-ray undulator beamline at the NSLS has been rebuilt to serve two microscopy stations operating simultaneously. Separate spherical-grating monochromators provide the resolving power required for XANES spectroscopy at the C, N and O absorption edges. The exit slits are fixed and define the coherent source for the experiments. The optical design and the operational performance are described.

Journal Article↗

PubMed2000

Tumor selective G2/M cell cycle arrest and apoptosis of epithelial and hematological malignancies by BBL22, a benzazepine.

Two distinct benzodiazepine binding sites have been identified, (i) a central site restricted to brain and (ii) a ubiquitously expressed mitochondrial binding site, the so-called peripheral-type benzodiazepine receptor (PBR). In this paper, we show that a benzazepine referred to as BBL22 (2-amino 9-chloro-7-(2-fluorophenyl)-5H-pyrimidol[5,4-d][2]benzazepine), which is classified as a PBR ligand based on structure, induces arrest in G(2)/M phase of the cell cycle in human tumor cell lines of both epithelial and hematopoietic cellular origin. After G(2)/M arrest, several tumor types, notably prostate and certain breast cancer lines exhibited significant apoptosis. Ideally, cancer therapies should selectively target tumor cells while sparing normal cell counterparts. BBL22 exhibited such selectivity, as it did not affect the growth and survival of nonmalignant breast and prostate epithelial lines. Moreover, BBL22 demonstrated structural requirements for this selective antitumor activity as 11 structurally related PBR ligands, including high-affinity ligands Ro5-4864 and PK11195, failed to induce tumor cell growth arrest or apoptosis. The in vivo antitumor activity of BBL22 was examined in a human xenograft model of androgen-independent prostate cancer where BBL22 significantly reduced the growth of PC3 prostate tumors without eliciting overt toxicity. Identification of BBL22 represents a tumor selective therapeutic strategy for a variety of human tumors.

Antineoplastic Agents↗

PubMed2000

Rational modification of protein stability by the mutation of charged surface residues.

Continuum methods were used to calculate the electrostatic contributions of charged and polar side chains to the overall stability of a small 41-residue helical protein, the peripheral subunit-binding domain. The results of these calculations suggest several residues that are destabilizing, relative to hydrophobic isosteres. One position was chosen to test the results of these calculations. Arg8 is located on the surface of the protein in a region of positive electrostatic potential. The calculations suggest that Arg8 makes a significant, unfavorable electrostatic contribution to the overall stability. The experiments described in this paper represent the first direct experimental test of the theoretical methods, taking advantage of solid-phase peptide synthesis to incorporate approximately isosteric amino acid substitutions. Arg8 was replaced with norleucine (Nle), an amino acid that is hydrophobic and approximately isosteric, or with alpha-amino adipic acid (Aad), which is also approximately isosteric but oppositely charged. In this manner, it is possible to isolate electrostatic interactions from the effects of hydrophobic and van der Waals interactions. Both Arg8Nle and Arg8Aad are more thermostable than the wild-type sequence, testifying to the validity of the calculations. These replacements led to stability increases at 52.6 degrees C, the T(m) of the wild-type, of 0.86 and 1.08 kcal mol(-)(1), respectively. The stability of Arg8Nle is particularly interesting as a rare case in which replacement of a surface charge with a hydrophobic residue leads to an increase in the stability of the protein.

Acetyltransferases↗

PubMed2000

Seizure precipitants and perceived self-control of seizures in adults with poorly-controlled epilepsy.

This study was set up in order to investigate the prevalence and nature of seizure precipitants and self-control behaviours in adults with intractable seizures. A semi-structured interview was conducted with 100 patients attending neurology or neuropsychiatry epilepsy out-patient clinics. The interview included six questions regarding seizure precipitants, the extent to which the patients seek and avoid precipitants, and their ability to induce or abort seizures. The study revealed that over 90% of the participants could identify at least one seizure precipitant. Stress, depression, tiredness and the menstrual cycle were the most common precipitants reported. In addition, 65% of the participants could identify at least one 'low-risk' situation in which seizures were unlikely to occur. Fifteen percent reported they could induce a seizure, 52% said that they consciously try to avoid seizure precipitants and 47% said they could sometimes stop their seizures from happening. These results indicate that the majority of the sample could identify factors which trigger their seizures, and that some of the participants engage in attempts to reduce their seizure frequency by avoiding these factors and by controlling the onset of their seizures. The possible mechanisms involved in the relationship between precipitants and seizure genesis are discussed.

Adult↗

PubMed2000

Sparfloxacin for the treatment of acute bacterial maxillary sinusitis documented by sinus puncture.

PURPOSE: To evaluate the efficacy and safety of sparfloxacin in the treatment of patients with acute bacterial maxillary sinusitis, the microbiologic etiology of which was determined by maxillary sinus puncture. PATIENTS AND METHODS: Two hundred fifty-three patients enrolled in the open, noncomparative trial received sparfloxacin as a 400-mg loading dose followed by 200 mg once daily doses for a total of 10 days. One hundred ninety-eight patients were clinically evaluable and 82 were also bacteriologically evaluable. All treated patients were included in the safety analysis. Overall success was determined based on clinical success (resolution or reduction of signs and symptoms and sinus x-rays) and bacteriologic success (eradication and presumed eradication of baseline pathogens obtained by maxillary sinus puncture and aspiration). RESULTS: Overall success in the bacteriologically evaluable population at test-of-cure was 91.5% [75/82; 95% confidence interval (85.4%, 97.5%)]. For all pathogens, the eradication rate was 93.2% (109/117 baseline pathogens); individual pathogen eradication rates were 88.9% (16/18) for S. pneumoniae (including those strains exhibiting decreased susceptibility to penicillin); and 100% for H. influenzae (17/17), S. aureus (14/14), and M. catarrhalis (11/11). The majority of adverse events were of mild or moderate severity; the most frequently related adverse events were photosensitivity reaction, headache, nausea, and diarrhea. CONCLUSION: Sparfloxacin had an overall success rate of 91.5% for patients in this study and was generally well tolerated in the treatment of acute bacterial maxillary sinusitis.

Acute Disease↗

PubMed2000

Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: I. Instrumentation, imaging and spectroscopy.

We have developed a cryo scanning transmission X-ray microscope which uses soft X-rays from the National Synchrotron Light Source. The system is capable of imaging frozen hydrated specimens with a thickness of up to 10 microm at temperatures of around 100 K. We show images and spectra from frozen hydrated eukaryotic cells, and a demonstration that biological specimens do not suffer mass loss or morphological changes at radiation doses up to about 1010 Gray. This makes possible studies where multiple images of the same specimen area are needed, such as tomography (Wang et al. (2000) Soft X-ray microscopy with a cryo scanning transmission X-ray microscope: II. Tomography. J. Microsc. 197, 80-93) or spectroscopic analysis.

3T3 Cells↗

PubMed2000

A standardized plaque reduction assay for determination of drug susceptibilities of cytomegalovirus clinical isolates.

Twelve laboratories collaborated in formulating and testing a standardized plaque reduction assay for cytomegalovirus (CMV) cell-associated clinical isolates. Four characterized and plaque-purified CMV strains, as well as six coded clinical isolates obtained after antiviral therapy, were distributed and tested. Good agreement was obtained for four of the clinical isolates, but a broad distribution of results was obtained for two isolates. Analysis of these results indicates the problems associated with clinical isolates, including the large genetic variability and the highly cell-associated phenotype. This collaborative effort, by addressing these problems, represents a significant step toward the development of a standardized assay.

Antiviral Agents↗

PubMed2000

Noncompliance with asthma therapy--are there solutions?

Compliance with medication is essential if treatment is to be effective. Noncompliance can include underuse, overuse, and erratic use of medication; underuse being the most frequently reviewed. Generally estimated to be around 10%-46%, noncompliance with asthma therapy is a serious problem and studies have shown that compliance with the mainstay of asthma treatment, inhaled corticosteroids, is low. Oral therapy offers better compliance with treatment, with many patients preferring tablets to inhalers. Different ways to monitor compliance include monitoring prescriptions, counting tablets, measuring levels of medication in blood or urine, and measuring canister weight, although none are fully effective. Contributing factors to noncompliance with treatment include side effects, lifestyle, social and economic factors, method of drug delivery, and dosing. The consequences of these include increased symptoms and asthma exacerbations, both of which can lead to increased morbidity. To improve compliance, causal factors need to be addressed; there is a need to educate patients and those who support them about the disease and the importance of following the physician's recommendations. Various self-management programs have also been established to improve patient compliance at a relatively low cost. Difficulties with treatment may be addressed by simplifying the treatment regimen using oral therapy. A relatively new class of oral agents, the leukotriene modifiers, is being increasingly used in clinical practice.

Asthma↗

PubMed1999

Submillisecond folding of the peripheral subunit-binding domain.

Folding and unfolding rates have been measured for the peripheral subunit-binding domain, a small three-helix protein. The protein folds very fast, with rates too rapid to be measured using traditional stopped-flow techniques. Folding and unfolding rates were measured as a function of temperature using dynamic NMR lineshape analysis. At the lowest temperature at which there is sufficient broadening to measure rates, 41 degrees C, the folding rate is 16,050 s(-1). Thus, the halftime required for folding is 43 micros. At the same temperature, the unfolding rate is 2800 s(-1). Identical rates were measured using resolved resonances from Val16 in the loop and Val21 at the end of the 310-helix. Folding rates have been correlated with protein topology, and this correlation is consistent with the rapid folding of the peripheral subunit-binding domain. The results presented here show that the peripheral subunit-binding domain is the third fastest folding protein for which rates have been estimated. The folding rate is the fastest that has been directly measured and provides further support for the importance of chain topology as a major determinant of folding rates.

Kinetics↗

PubMed1999

Pharmacological characterization of morphine-6-sulfate and codeine-6-sulfate.

Morphine-6-sulfate (M6S) and codeine-6-sulfate (C6S) are mu-selective opiates which have been isolated from brain. M6S is an effective analgesic, with a 30-fold greater potency than morphine in the mouse radiant heat tailflick assay and similar to the active morphine metabolite morphine-6beta-glucuronide (M6G). M6S analgesia is reversed by 3-methoxynaltrexone at low antagonist doses which are inactive against morphine, suggesting that M6S may be acting through the same mechanisms as M6G. Consistent with this possibility, antisense mapping of the MOR-1 clone revealed that M6S analgesia was lowered by probes targeting exon 2 and not by targeting exon 1, a sensitivity profile similar to that of M6G and not morphine. C6S also has analgesic activity at doses approximately 10-fold greater than M6S. However, its characterization was impeded by the appearance of seizures at doses below full analgesic activity. Thus, M6S is a potent analgesic with pharmacological properties similar to M6G. C6S has limited utility due to its high level of toxicity.

Analgesics, Opioid↗

PubMed1999

Nativelike structure and stability in a truncation mutant of a protein minidomain: the peripheral subunit-binding domain.

Despite its small size, the peripheral subunit-binding domain from the dihydrolipoamide acetyltransferase component of the Bacillus stearothermophilus pyruvate dehydrogenase multienzyme complex adopts a unique, compact structure. To determine whether the full 43 residue sequence is required for the domain to adopt a stable, nativelike structure, 3 proteins of different lengths were prepared. Psbd41 corresponds to residues 3-43 of the domain, psbd36 spans residues 6-41, and psbd33 comprises residues 7-39. Psbd41 folds in a cooperative, two-state fashion with a Tm of 53 degrees C and a stability at 25 degrees C of 2.2 kcal mol-1. Psbd36 is nearly as stable with a Tm of 48 degrees C and a stability of 1.8 kcal mol-1. Similar m-values and heat capacities suggest that psbd36 and psbd41 bury approximately the same surface area. Minimal differences in CalphaH and NH chemical shifts between psbd41 and psbd36 show that the two sequences adopt the same tertiary fold. On a per residue basis, DeltaH degrees and DeltaC degrees p fall within the range typical for single-domain globular proteins. Psbd33 is significantly less stable. It is not fully folded at 25 degrees C, and at all temperatures it shows broadened NMR lines. ANS titrations provide evidence that this is due to an equilibrium between nativelike and unfolded molecules rather than formation of a molten globule. The fraction of psbd33 molecules which are folded appear to adopt the same structure as the full-length domain. Thus, although more than the 33 residue core is required to form a fully stable native structure, the entire sequence is not required for folding.

Amino Acid Sequence↗