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PubMed2006

Clinical trials and the response rate illusion.

Clinical trial outcome data can be presented and analyzed as mean change scores or as response rates. These two methods of presenting the data can lead to divergent conclusions. This article explores the reasons for the apparently divergent outcomes produced by these methods and considers their implications for the analysis and reportage of clinical trial data. It is shown that relatively small differences in improvement scores can produce relatively large differences in expected response rates. This is because differences in response rates do not indicate differences in the number of people who have improved; they indicate differences in the number of people whose degree of improvement has pushed them over a specified criterion. Therefore, patients classified as non-responders may have shown substantial and clinically significant improvement, and these are the patients who are most likely to become responders when given medication. Response rates based on continuous data do not add information, and they can create an illusion of clinical effectiveness.

Antidepressive Agents↗
PubMed2000

Capillary zone electrophoresis of a recombinant adenovirus.

Adenovirus preparations are used as vectors in a number of gene therapy clinical development programs. The success of commercial production of adenovirus will strongly depend on the development of methods to define the recombinant virus product by analysis as opposed to being defined by the manufacturing process. While most analytical techniques examine portions of the virus, e.g. proteins or DNA, ion-exchange chromatography has been used to separate intact virus at low efficiency. A free zone capillary electrophoretic method was developed for high-efficiency separations of adenovirus 5. Experimental conditions such as buffer pH and concentration were explored which produced a high-efficiency separation in less than 20 min. The virus band was identified by collection of CE fractions and examination using a cell based assay. Initially, a single virus peak is found in fresh virus samples. After as little as one freeze-thaw in 1 x phosphate-buffered saline with 2% sucrose, the active virus migrates as a regular series of peaks. The nature of the virus modification leading to the differing electrophoretic mobilities is presently under investigation.

Adenoviridae↗
PubMed2005

Corneal melt after amniotic membrane transplant.

PURPOSE: To report an eye-threatening complication associated with amniotic membrane grafting. DESIGN: Interventional case report. METHODS: Retrospective review of the clinical and surgical records of a 43-year-old man who developed melting of his corneal graft after amniotic membrane transplantation. RESULTS: Melting of a corneal graft after amniotic membrane transplantation was arrested by utilizing a tectonic, full-thickness corneal button denuded of endothelium in conjunction with a temporary tarsorraphy and systemic steroids. CONCLUSIONS: To the best of our knowledge, this is the first report of an eye-threatening complication associated with amniotic membrane grafting. Caution should be exercised in utilizing amniotic membrane in patients who have undergone multiple ophthalmologic surgical procedures, which may sensitize the ocular immune system or lead to localized ischemia.

Adult↗
PubMed2001

The in situ supermolecular structure of type I collagen.

BACKGROUND: The proteins belonging to the collagen family are ubiquitous throughout the animal kingdom. The most abundant collagen, type I, readily forms fibrils that convey the principal mechanical support and structural organization in the extracellular matrix of connective tissues such as bone, skin, tendon, and vasculature. An understanding of the molecular arrangement of collagen in fibrils is essential since it relates molecular interactions to the mechanical strength of fibrous tissues and may reveal the underlying molecular pathology of numerous connective tissue diseases. RESULTS: Using synchrotron radiation, we have conducted a study of the native fibril structure at anisotropic resolution (5.4 A axial and 10 A lateral). The intensities of the tendon X-ray diffraction pattern that arise from the lateral packing (three-dimensional arrangement) of collagen molecules were measured by using a method analogous to Rietveld methods in powder crystallography and to the separation of closely spaced peaks in Laue diffraction patterns. These were then used to determine the packing structure of collagen by MIR. CONCLUSIONS: Our electron density map is the first obtained from a natural fiber using these techniques (more commonly applied to single crystal crystallography). It reveals the three-dimensional molecular packing arrangement of type I collagen and conclusively proves that the molecules are arranged on a quasihexagonal lattice. The molecular segments that contain the telopeptides (central to the function of collagen fibrils in health and disease) have been identified, revealing that they form a corrugated arrangement of crosslinked molecules that strengthen and stabilize the native fibril.

Collagen Type I↗
PubMedDate not supplied

GC/MS analysis of phencyclidine acid metabolite in human urine.

Available methods for determining PCP use are based on the presence of the parent drug in urine. PCP, however, is very potent and is extensively metabolized; it is therefore present in urine in only small quantities. This work was undertaken to determine whether an amino acid metabolite of PCP, 5-(N-(1'-phenylcyclohexyl)amino)pentanoic acid, can be used to determine PCP use. A solid phase adsorption technique was developed to extract the amino acid metabolite from urine. Recovery averaged 93%, and subsequent GC/MS analysis was free from interference. Analysis of 67 urine samples demonstrated that the amino acid metabolite exists in human urine in significant quantities.

Gas Chromatography-Mass Spectrometry↗
PubMed2006

Uniformly-sized, molecularly imprinted polymers for nicotine by precipitation polymerization.

Uniformly-sized, molecularly imprinted polymers (MIPs) for (S)-nicotine have been prepared by a precipitation polymerization method using methacrylic acid (MAA) or 2-(trifluoromethyl)acrylic acid (TFMAA) as a functional monomer and divinylbenzene (DVB) as a cross-linker in a mixture of toluene and acetonitrile. The (S)-nicotine-imprinted MAA-co-DVB polymers were monodispersed microspheres of about 4 microm in diameter, while the TFMAA-co-DVB ones were gel-like. Molecular recognition abilities of the former MIPs were evaluated for nicotine and its structurally related compounds in liquid chromatography using a mixture of sodium phosphate buffer and acetonitrile as the eluent. Enantioseparation of nicotine was attained using the (S)-nicotine-imprinted MAA-co-DVB polymers. Furthermore, they could selectively trap nicotine in cigarette smoke extracts.

Chemical Precipitation↗
PubMed2001

Protein structural alignments and functional genomics.

Structural genomics-the systematic solution of structures of the proteins of an organism-will increasingly often produce molecules of unknown function with no close relative of known function. Prediction of protein function from structure has thereby become a challenging problem of computational molecular biology. The strong conservation of active site conformations in homologous proteins suggests a method for identifying them. This depends on the relationship between size and goodness-of-fit of aligned substructures in homologous proteins. For all pairs of proteins studied, the root-mean-square deviation (RMSD) as a function of the number of residues aligned varies exponentially for large common substructures and linearly for small common substructures. The exponent of the dependence at large common substructures is well correlated with the RMSD of the core as originally calculated by Chothia and Lesk (EMBO J 1986;5:823-826), affording the possibility of reconciling different structural alignment procedures. In the region of small common substructures, reduced aligned subsets define active sites and can be used to suggest the locations of active sites in homologous proteins.

Bacillus subtilis↗
PubMed2006

The detection of sedatives in hair and nail samples using tandem LC-MS-MS.

Drug screening methods were developed to detect alprazolam, clobazam, clonazepam, diazepam, midazolam, oxazepam, temazepam, triazolam, zopiclone, and selected metabolites in human hair and nail samples employing liquid-liquid extraction and tandem liquid chromatography-mass spectrometry (LC-MS-MS). Hair and nail samples were obtained from patients who had recently discontinued or were currently prescribed one or more of the targeted drugs. Prazepam was used as the internal standard for all compounds. Some components in the hair matrix gave the same transitions as some of the analytes but did not compromise the analyses because their retention times differed from those for the target compounds. The analytical run time was 8-10min. Results of the hair analysis of a DFSA victim are also presented.

Adult↗
PubMed2006

Reports of abusive experiences during childhood and adult health ratings: personal control as a pathway?

OBJECTIVE: This study examines the relationship between reports of childhood abuse and self-rated health in adulthood, and the potential of personal control to serve as a mediator. METHOD: Regression models were estimated using data from the National Survey of Midlife Development in the United States (MIDUS). RESULTS: Reported emotional abuse was associated with lower personal control. In addition, women who reported emotional abuse by mother or both parents were more likely than women who were not abused to report lower self-rated health. The relationship between emotional abuse by both parents and self-rated health was mediated by personal control. DISCUSSION: The findings suggest that there are long-term health consequences of early childhood abuse. The effects of childhood abusive experiences, however, operate differently for men and women and are dependent on the outcome examined. Childhood abuse compromises personal control that, in turn, leads to lower health ratings.

Adult↗
PubMed1976

Febrile illnesses resulting in hospital admission: a bacteriological and serological study in Jakarta, Indonesia.

A study of 741 Indonesian patients with fever was carried out in order to determine what serious febrile illnesses are prevalent in Jakarta. All patients were hospitalized primarily because of fever and were studied by bacteriological and serological methods. Bacteremia due to Salmonella typhi (150 cases), S. enteritidis (36 cases), or both (2 cases) was common in both children and adults. One S. enteritidis isolate was chloramphenicol resistant. Serological evidence of Salmonella infection was found in 130 additional cases without bacteremia. Serological evidence of arbovirus infection (94 cases) was common in children. Malaria was found in 12 adults, most of whom were probably infected outside Jakarta. Little serological evidence was found for rickettsial, leptospiral, Brucella, Toxoplasma gondii or a number of other infections. Clinical signs and symptoms in the febrile patients studed were generally nonspecific, and laboratory results reported were very helpful in establishing more accurate diagnoses.

Arbovirus Infections↗
PubMed2004

Spin-lattice relaxation and a fast T1-map acquisition method in MRI with transient-state magnetization.

The magnetization under the spin-lattice relaxation and the nuclear magnetic resonance radiofrequency (RF) pulses is calculated for a signal RF pulse train and for a sequence of multiple RF pulse-trains. It is assumed that the transverse magnetization is zero when each RF pulse is applied. The result expressions can be grouped into two terms: a decay term, which is proportional to the initial magnetization M0, and a recovery term, which has no M0 dependence but strongly depends on the spin-lattice relaxation and the equilibrium magnetization Meq. In magnetic resonance pulse sequences using magnetization in transient state, the recovery term produces artifacts and can seriously degrade the function of the preparation sequence for slice selection, contrast weighting, phase encoding, etc. This work shows that the detrimental effect can be removed by signal averaging in an eliminative fashion. A novel fast data acquisition method for constructing the spin-lattice relaxation (T1) map is introduced. The method has two features: (i) By using eliminative averaging, the curve to fit the T1 value is a decay exponential function rather than a recovery one as in conventional techniques; therefore, the measurement of Meq is not required and the result is less susceptible to the accuracy of the inversion RF pulse. (ii) The decay exponential curve is sampled by using a sequence of multiple pulse-trains. An image is reconstructed from each train and represents a sample point of the curve. Hence a single imaging sequence can yield multiple sample points needed for fitting the T1 value in contrast to conventional techniques that require repeating the imaging sequence for various delay values but obtain only one sample point from each repetition.

Algorithms↗
PubMedDate not supplied

Cell-based therapy for disc repair.

BACKGROUND CONTEXT: One of the most promising therapies for symptomatic disc degeneration involves the implantation of therapeutic cells into the degenerative disc. PURPOSE: In this article, the rationale and approaches for cell-based tissue engineering of the intervertebral disc are discussed. STUDY DESIGN: The scientific literature related to cell-based tissue engineering of the intervertebral disc is reviewed. METHODS: A variety of cell types have been used in various research models to affect matrix repair of the intervertebral disc. The use of cellular scaffolds and growth factors or genes also appears promising for achieving meaningful tissue repair of the intervertebral disc. RESULTS: Disc tissue engineering is a promising approach for achieving repair of the intervertebral disc. Using cell-based approaches, various research models suggest that improvements in the complex matrix of the disc may be achieved. CONCLUSION: A cell-based approach to repair of the intervertebral disc appears promising. More research is needed to define the optimal cell type, cellular scaffold and mixture of growth factors that may allow meaningful repair of the human symptomatic degenerative disc.

Animals↗
PubMed1998

Gene expression by single Reed-Sternberg cells: pathways of apoptosis and activation.

Although Hodgkin's disease is highly responsive to treatments that cause apoptosis, it remains resistant to the physiological mechanisms intended to cause cell death. Presumably, the Reed-Sternberg cell defies endogenous apoptosis, persists, accumulates, and manifests the malignant disorder seen clinically. The Reed-Sternberg cell expresses several members of the tumor necrosis factor receptor superfamily. This family of receptors is involved in both activation and proliferation of cells, as well as either protection from or initiation of apoptosis in cells expressing these surface proteins. Signals from these receptors affect transcription. We reasoned that the activation state and resistance to apoptosis of Reed-Sternberg cells might be attributable to dysregulation of genes controling these processes. To determine gene expression by Reed-Sternberg cells, we developed a method of micromanipulation, global reverse transcription, and the reverse transcription-polymerase chain reaction and applied it to 51 single Reed-Sternberg cells and their variants from six cases of Hodgkin's disease. This report analyzes the gene expression of bcl-xs, bcl-xl, bax-alpha, bax-beta, fadd, fas, fas ligand (fas L), ice, TNF-alpha, TNF-beta, TNFR1, TNFR2, TRAF1, TRAF2, TRAF3, cIAP2, and tradd at the level of mRNA in the single Reed-Sternberg cells and their variants. The findings here suggest a molecular mechanism for the activated state and in vivo survival occurring in untreated Reed-Sternberg cells of Hodgkin's disease.

Apoptosis↗
PubMed2003

Identification of a GABA-containing cerebral-buccal interneuron-11 in Aplysia californica.

The cerebral-buccal interneurons (CBIs) in Aplysia are a group of inter-ganglionic projection neurons that regulate feeding motor programs. In this study, electrophysiological and immunocytological methods were used to identify a previously uncharacterized CBI, designated CBI-11. CBI-11 is a gamma-aminobutyric acid (GABA)-immunoreactive neuron located in the G cluster of the cerebral ganglion. Firing CBI-11 produced fast picrotoxin-sensitive inhibitory postsynaptic potentials (IPSPs) in buccal motor neuron B3. Local application of GABA to B3 produced a picrotoxin-sensitive hyperpolarization that reversed at the same membrane potential as the IPSPs elicited by stimulation of CBI-11. Together, these observations indicate that CBI-11 utilizes GABA as its transmitter. Finally, stimulation of CBI-11 elicited rhythmic motor programs in quiescent buccal ganglia. Thus, CBI-11 is a GABAergic CBI that can function as a motor program initiator.

Animals↗
PubMed2004

A national study examining the effect of making emergency hormonal contraception available without prescription.

BACKGROUND: In January 2001, emergency hormonal contraception was made available for women over the age of 16 years directly from a pharmacist without prescription. It is of interest whether this change in the UK has led to any improvements or deterioration in the service provided for the women who need it. METHODS: Self- completed, anonymous questionnaires were distributed to women requesting emergency hormonal contraception through a single group of pharmacies located throughout England, Wales and Scotland. RESULTS: A total 419 women returned completed questionnaires. A greater proportion of women were able to take emergency contraception within 24 h when they obtained their tablets directly from a pharmacy without a prescription (64% versus 46%, P = 0.029). Women who obtained their drugs directly from the pharmacist were just as well informed, just as likely to arrange regular follow-up and generally preferred this system, although they disliked having to pay. CONCLUSION: Making emergency hormonal contraception available without prescription has improved services to women who need them, but these improvements are quantitatively minimal, preventing only five additional pregnancies per 10,000 users.

Contraceptives, Postcoital, Hormonal↗
PubMed1986

Polyethylene glycol polymers of low molecular weight as probes of intestinal permeability. I. Innovations in analysis and quantitation.

The differential passive permeation of polymers of different lengths across the intestinal mucosa has been proposed as a probe to test mucosal integrity under a variety of physiologic and pathologic conditions. Polyethylene glycol (PEG) 400 contains a series of polymers whose pattern of urinary recovery after oral administration has been used to characterize intestinal mucosal function. To extend this method to the low levels of PEG polymers found in the urine of children with diarrhea, we have introduced three methodologic innovations. These alterations involve (1) formulation of a balanced PEG polymer mixture, (2) improved isolation, derivatization, and gas chromatography techniques, and (3) a new quantification of the pattern of PEG urinary recoveries. Urinary recovery of orally administered PEG was assessed in four normal adults, six hospitalized infants without gastrointestinal complains, two infants with prolonged diarrhea and carbohydrate malabsorption, and two children with cystic fibrosis. A parameter characterizing the urinary recovery of PEG, N1/2, which is the theoretical number of subunits in the polymer whose recovery is reduced to 50% of the value of the polymer whose recovery is maximal, gave stable, reproducible, and consistent results in normal adults and infants.

Adult↗
PubMed2001

Interferon plus amantadine versus interferon alone in the treatment of naïve patients with chronic hepatitis C: a UK multicentre study.

BACKGROUND/AIMS: The antiviral agent amantadine may have activity against the hepatitis C virus. To determine whether the combination of interferon-alpha plus amantadine was more effective than interferon monotherapy we conducted a multicentre clinical trial in untreated patients with chronic hepatitis C infection. METHODS: We performed a pilot study in two centres (36 patients) to determine the number needed for a statistically significant clinical trial and then conducted a multicentre, randomized controlled clinical trial involving 14 centres and 143 patients. RESULTS: There was no significant difference in sustained response rates in patients receiving interferon and amantadine compared to those receiving interferon alone. The on treatment response rate at 3 months was 65% on combination vs. 49% on interferon alone (P = 0.05) while the sustained response was 18 and 15%, respectively. CONCLUSIONS: Combination therapy with interferon plus amantadine does not lead to a significant increase in sustained response rates when compared to interferon monotherapy.

Adult↗
PubMed2006

Rapid, real-time detection of acute HIV infection in patients in Africa.

BACKGROUND: We conducted a prospective study to evaluate methods of detecting clients with sexually transmitted diseases (STDs) who were acutely coinfected with human immunodeficiency virus (HIV) in Lilongwe, Malawi. METHODS: After informed consent was obtained, all clients with acute STDs were offered voluntary HIV counseling and testing by 2 rapid antibody tests. Samples from rapid test-negative or -discordant subjects were pooled (50 : 5 : 1) and tested for HIV RNA. Western blots were performed on all rapid test-discordant specimens with detectable HIV RNA. A subset of specimens received p24 antigen testing with standard and/or ultrasensitive methods. Patients with possible acute HIV infection were followed to confirm seroconversion. RESULTS: A total of 1450 clients (34% female and 66% male) agreed to testing, of whom 588 (40.55%) had established HIV infection and 21 (1.45%) had acute infection. Discordant rapid antibody tests identified 7 of 21 (33.3% sensitivity), standard p24 antigen identified 12 of 16 (75% sensitivity), and ultrasensitive p24 antigen identified 15 of 17 (88% sensitivity) acute cases. By definition, the sensitivity of the RNA assay was 100%. CONCLUSIONS: Real-time pooled RNA testing for the detection of acute HIV infection is feasible in resource-limited settings. However, parallel rapid testing and p24 antigen testing are technologically simpler and together may detect approximately 90% of acute cases.

Acute Disease↗