Breast cancer diagnosis using scattered X-rays

Small-angle X-ray diffraction data has been collected from 99 ;core-cut' breast tissue specimens representing a number of different pathologies. Data in the range 75-1390 A have been compared with controls from patients with no breast disease. Bessel functions and Bragg maxima resulting from the fibrillar structure of collagen have been identified. The Bragg maxima indexed onto a 649 A lattice. Systematic differences in the intensities and D-spacings between the collagen of malignant, benign and normal tissue groups have been clearly demonstrated and quantified. These differences appear to be due to a significantly lower structural order within the malignant tissues. Possible explanations for this are discussed and the potential for utilizing this observation in cancer diagnosis is considered.

Mutations in MKKS cause obesity, retinal dystrophy and renal malformations associated with Bardet-Biedl syndrome

Bardet-Biedl syndrome (BBS) is an autosomal recessive disorder predominantly characterized by obesity, retinal dystrophy, polydactyly, learning difficulties, hypogenitalism and renal malformations, with secondary features that include diabetes mellitus, endocrinological dysfunction and behavioural abnormalities. Despite an initial expectation of genetic homogeneity due to relative clinical uniformity, five BBS loci have been reported, with evidence for additional loci in the human genome; however, no genes for BBS have yet been identified. We performed a genome screen with BBS families from Newfoundland that were excluded from BBS1-5 and identified linkage with D20S189. Fine-mapping reduced the critical interval to 1.9 cM between D20S851 and D20S189, encompassing a chaperonin-like gene. Mutations in this gene were recently reported to be associated with McKusick-Kaufman syndrome (MKKS; ref. 8). Given both the mapping position and clinical similarities of these two syndromes, we screened MKKS and identified mutations in five Newfoundland and two European-American BBS pedigrees. Most are frameshift alleles that are likely to result in a non-functional protein. Our data suggest that a complete loss of function of the MKKS product, and thus an inability to fold a range of target proteins, is responsible for the clinical manifestations of BBS.

Field-induced phase transitions in an antiferroelectric liquid crystal using the pyroelectric effect

The antiferroelectric liquid crystal (AFLC) under investigation possesses different helical polar phases. Measurements of pyroelectric response of these phases as a function of temperature and bias field have elucidated the ability of this method for investigating the nature of antiferroelectric phases and phase transitions under the bias field. The pyroelectric signal as a function of the bias field at fixed temperatures and as a function of temperature for fixed bias fields was measured for different phases of the investigated AFLC material. A theoretical model describing the pyroelectric response in different phases of AFLC is given, and the experimental results are interpreted. The threshold fields for field induced phase transitions are determined. The type of field induced phase transition from the AF phase in particular is found to be dependent on the temperature within its range. The properties of an unusual ferrielectric phase existing between ferrielectric chiral smectic-C (SmC*) and antiferroelectric AF phases are studied in a great detail. The results confirm that this phase is one of the incommensurate phases, predicted by the axial next-nearest neighbor Ising model and Landau model for this temperature region.

Neurological dysfunction and axonal degeneration in Charcot-Marie-Tooth disease type 1A

Charcot-Marie-Tooth disease type 1A (CMT1A), the most frequent form of CMT, is caused by a 1.5 Mb duplication on the short arm of chromosome 17. Patients with CMT1A typically have slowed nerve conduction velocities (NCVs), reduced compound motor and sensory nerve action potentials (CMAPs and SNAPs), distal weakness, sensory loss and decreased reflexes. In order to understand further the molecular pathogenesis of CMT1A, as well as to determine which features correlate with neurological dysfunction and might thus be amenable to treatment, we evaluated the clinical and electrophysiological phenotype in 42 patients with CMT1A. In these patients, muscle weakness, CMAP amplitudes and motor unit number estimates correlated with clinical disability, while motor NCV did not. In addition, loss of joint position sense and reduction in SNAP amplitudes also correlated with clinical disability, while sensory NCV did not. Taken together, these data strongly support the hypothesis that neurological dysfunction and clinical disability in CMT1A are caused by loss or damage to large calibre motor and sensory axons. Therapeutic approaches to ameliorate disability in CMT1A, as in amyotrophic lateral sclerosis and other neurodegenerative diseases, should thus be directed towards preventing axonal degeneration and/or promoting axonal regeneration.

Case report: acute urinary retention secondary to Isaacs' syndrome

We report an unusual case of acute urinary retention secondary to Isaacs' syndrome due to external urethral sphincter spasm. The patient was able to resume spontaneous voiding after the treatment of the underlying disease. At 6-month follow-up, there were no voiding complaints.

Macular degeneration: the emerging genetics

Discovery of the gene responsible for a recessive, early-onset maculopathy has focused attention on a biomolecular pathway in which subtle metabolic flaws become toxic to irreplaceable retinal cells. The pathway's identification points toward specific ways of intervening. Among patients with age-related macular degeneration, carriers of single mutations in the same gene are proving to be remarkably common.

Vision loss as the presenting sign in juvenile neuronal ceroid lipofuscinosis

OBJECTIVE

To review cases of juvenile neuronal ceroid lipofuscinosis (JNCL) and highlight salient clinical and diagnostic features, thereby enhancing recognition of this disease among ophthalmologists.

MATERIALS AND METHODS

Twelve cases of JNCL seen from 1982 to 1999 were reviewed. Diagnosis was based on characteristic clinical history, ophthalmoscopic findings, electroretinography, neuroimaging, histopathology, and molecular analysis.

RESULTS

Vision loss was the first subjective symptom of the disease in all 12 cases. Among these cases, nine of 12 patients (75%) developed neurologic deficits an average of 3 years after the onset of visual deterioration.

CONCLUSION

Because visual symptoms usually precede neurologic dysfunction, JNCL should be considered in the differential diagnosis when an apparently healthy child presents with unexplained bilateral vision loss.

Genomic rearrangement in NEMO impairs NF-kappaB activation and is a cause of incontinentia pigmenti. The International Incontinentia Pigmenti (IP) Consortium

Familial incontinentia pigmenti (IP; MIM 308310) is a genodermatosis that segregates as an X-linked dominant disorder and is usually lethal prenatally in males. In affected females it causes highly variable abnormalities of the skin, hair, nails, teeth, eyes and central nervous system. The prominent skin signs occur in four classic cutaneous stages: perinatal inflammatory vesicles, verrucous patches, a distinctive pattern of hyperpigmentation and dermal scarring. Cells expressing the mutated X chromosome are eliminated selectively around the time of birth, so females with IP exhibit extremely skewed X-inactivation. The reasons for cell death in females and in utero lethality in males are unknown. The locus for IP has been linked genetically to the factor VIII gene in Xq28 (ref. 3). The gene for NEMO (NF-kappaB essential modulator)/IKKgamma (IkappaB kinase-gamma) has been mapped to a position 200 kilobases proximal to the factor VIII locus. NEMO is required for the activation of the transcription factor NF-kappaB and is therefore central to many immune, inflammatory and apoptotic pathways. Here we show that most cases of IP are due to mutations of this locus and that a new genomic rearrangement accounts for 80% of new mutations. As a consequence, NF-kappaB activation is defective in IP cells.

Factor Xa inhibitors (Berlex)

Berlex Biosciences is investigating several series of Factor Xa inhibitors aimed at the prevention and treatment of thrombotic disorders [297584]. Some compounds are based on the structure of ZK-805412, a Z,Z-2,7-bis(dibenzylidene)cycloheptanone, which showed nanomolar Factor Xa inhibitor potency [301618]. Specific inhibitors identified in the program include ZK-806350 and ZK- 807191. Other series include condensed diphenoxypyridines, indoles, benzimidazoles and carbazoles [279707,279714,297584, 279710,279716,279718]. The inhibitory activity of 2,6-diphenoxypyridines on Factor Xa has been demonstrated in vitro [328787]. Berlex and Warner-Lambert are collaborating on Factor Xa inhibitors [347062].

Multiple CYP1B1 mutations and incomplete penetrance in an inbred population segregating primary congenital glaucoma suggest frequent de novo events and a dominant modifier locus

Primary congenital glaucoma (PCG) is an autosomal recessive disorder associated with unknown developmental defect(s) in the anterior chamber. Recently, we reported three distinct mutations in CYP1B1, the gene for cytochrome P4501B1, in 25 Saudi families segregating PCG. For this report, we analyzed 37 additional families and confirmed the initial finding of decreased penetrance. Mutations and intragenic single-nucleotide polymorphisms (SNPs) were also analyzed from direct sequencing of all CYP1B1 coding exons. Eight distinct mutations were identified: G61E, R469W and D374N, the most common Saudi mutations, account for 72, 12 and 7%, respectively, of all the PCG chromosomes. Five additional homozygous mutations (two deletions and three missense mutations) were detected, each in a single family. Affected individuals from five families had no CYP1B1 coding mutations, and each family had a unique SNP profile. The identification of eight distinct mutations in a single gene, on four distinct haplotypes, suggests a relatively recent occurrence of multiple mutations in CYP1B1 in Saudi Arabia. These data demonstrate decreased penetrance of the PCG phenotype in the Saudi population, because 40 apparently unaffected individuals in 22 families have mutations and haplotypes identical to their affected siblings. Two individuals were subsequently diagnosed with glaucoma and two others had abnormal ocular findings that are consistent with milder forms of glaucoma. Analysis of these 22 kindreds suggests the presence of a dominant modifier locus that is not linked genetically to CYP1B1. Linkage and Southern analyses excluded three candidate modifier loci.

MecI represses synthesis from the beta-lactamase operon of Staphylococcus aureus

Plasmid diploids were constructed in Staphylococcus aureus to study the effect of the repressor of methicillin resistance (MecI) on the synthesis of both beta-lactamase and the beta-lactamase repressor (BlaI). MecI-mediated repression of the synthesis of beta-lactamase was shown by reduction in the specific activity of nitrocefinase in bacteria containing a plasmid carrying mecI but not when containing the same plasmid deleted for mecI. Antisera prepared against purified MecI and against purified BlaI were used in Western blots which showed that MecI repressed the synthesis of BlaI in these diploids. The interactions between the mec operon and the bla operon are discussed.

Complex inheritance of ABCR mutations in Stargardt disease: linkage disequilibrium, complex alleles, and pseudodominance

Stargardt disease is a recessively transmitted disease caused by mutations in the ABCR gene. Linkage disequilibrium has recently been reported between a polymorphism, 2828 A, and a common Western European founder mutation, 2588 C. Here, we confirm this linkage disequilibrium in a North American population. We also describe two complex alleles involving the 2828 A and 2588 C alterations and suggest a possible order of clinical severity of mutations identified in trans to the complex alleles. Finally, we report pseudodominance of Stargardt disease in a family with the 2588 C mutation, further supporting a high frequency of carriers for ABCR mutations in our population.

Charcot-Marie-Tooth disease type 1: molecular pathogenesis to gene therapy

Charcot-Marie-Tooth disease type 1 (CMT1) is caused by mutations in the peripheral myelin protein, 22 kDa (PMP22) gene, protein zero (P0) gene, early growth response gene 2 (EGR-2) and connexin-32 gene, which are expressed in Schwann cells, the myelinating cells of the peripheral nervous system. Although the clinical and pathological phenotypes of the various forms of CMT1 are similar, including distal muscle weakness and sensory loss, their molecular pathogenesis is likely to be quite distinct. In addition, while demyelination is the hallmark of CMT1, the clinical signs and symptoms of the disease are probably produced by axonal degeneration, not demyelination itself. In this review we discuss the molecular pathogenesis of CMT1, as well as approaches to an effective gene therapy for this disease.

Ziprasidone for schizophrenia and severe mental illness

BACKGROUND

Typical antipsychotic drugs are widely used as the first line treatment for people with schizophrenia. However, the atypical class of antipsychotic drugs are making important inroads into this approach. Atypical is a widely used term used to describe some antipsychotics which have a low propensity to produce movement disorders, sedation and raised serum prolactin. There is some suggestion that the different adverse effect profiles of the atypical antipsychotic group make them more acceptable to people with schizophrenia. Ziprasidone is one of the newer atypicals with a high serotonin/dopamine receptor affinity.

OBJECTIVES

To determine the effects of ziprasidone compared with placebo, typical and other atypical antipsychotic drugs for schizophrenia and related psychoses.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1980-1999), The Cochrane Library (Issue 1, 1999), The Cochrane Schizophrenia Group's Register (January 1999), EMBASE (1980-1999), MEDLINE (1966-1999), LILACS (1982-1996), PSYNDEX (1977-1995) and PsycLIT (1974-1999) were undertaken. In addition, pharmaceutical databases on the Dialog Corporation Datastar and Dialog services were searched. References of all identified studies were searched for further trials. Pharmaceutical companies and authors of trials were contacted.

SELECTION CRITERIA

All randomised controlled trials that compared ziprasidone to other treatments for schizophrenia and schizophrenia-like psychoses were included by independent assessment.

DATA COLLECTION AND ANALYSIS

Citations and, where possible, abstracts were independently inspected by reviewers, papers ordered, re-inspected and quality assessed. Data were independently extracted. Data were excluded if loss to follow up was greater than 50%. For homogeneous dichotomous data the risk ratio (RR), 95% confidence interval (CI) and, where appropriate, the number needed to treat (NNT) were calculated on an intention-to-treat basis. For continuous data, weighted mean differences were calculated (WMD). All data were inspected for heterogeneity.

MAIN RESULTS

Data for this compound range from very short (1 week) studies of the intramuscular preparation, to trials lasting over six months. For measures of mental state ziprasidone seems more effective than placebo (RR 0.8 CI 0.7-0.9) and as effective as haloperidol (RR 0.8 CI 0.7-1). It is less likely than haloperidol to cause movement disorders (RR 0.4 CI 0.2-0.6), but may cause more nausea and vomiting (RR 2.1 CI 1.2-3.8). The injected form of the drug may cause more pain at the injection site than haloperidol (RR 5.3 CI 1.3-22).

REVIEWER'S CONCLUSIONS

Currently data are limited. Ziprasidone may be an effective antipsychotic with less extrapyramidal effects than haloperidol. It also may, however, cause more nausea and vomiting than the typical drugs, and, at present, there is no data suggesting that it is different to other atypical compounds. Well planned, conducted and reported long term randomised trials are needed if ziprasidone is to be accepted into everyday use.

Novel mutations in XLRS1 causing retinoschisis, including first evidence of putative leader sequence change

Juvenile retinoschisis is an X-linked recessive disease caused by mutations in the XLRS1 gene. We screened 31 new unrelated patients and families for XLRS1 mutations in addition to previously reported mutations for 60 of our families (Retinoschisis Consortium, Hum Mol Genet 1998;7:1185-1192). Twenty-three different mutations including 12 novel ones were identified in 28 patients. Mutations identified in this study include 19 missense mutations, two nonsense mutations, one intragenic deletion, four microdeletions, one insertion, and one intronic sequence substitution that is likely to result in a splice site defect. Two novel mutations, c.38T-->C (L13P) and c.667T-->C (C223R), respectively, present the first genetic evidence for the functional significance of the putative leader peptide sequence and for the functional significance at the carboxyl terminal of the XLRS1 protein beyond the discoidin domain. Mutations in 25 of the families were localized to exons 4-6, emphasizing the critical functional significance of the discoidin domain of the XLRS1 protein.

Proteolytic cleavage of the repressor (BlaI) of beta-lactamase synthesis in Staphylococcus aureus

The proteolytic cleavage of BlaI was shown to correlate with beta-lactamase synthesis in Staphylococcus aureus. BlaI was found to be autoregulatory when expressed from the blaZ promoter. Insertion of a 10-bp linker into the SnaBI site of blaRI resulted in constitutive synthesis of beta-lactamase.

Electrophysiologic features of inherited demyelinating neuropathies: a reappraisal

The observation that inherited demyelinating neuropathies tend to have uniform conduction slowing and acquired disorders (CIDP and variants) have nonuniform or multifocal slowing was made before the identification of genetic defects of specific myelin constituents that cause the different forms of Charcot-Marie-Tooth and other inherited disorders involving peripheral nerve myelin. It is becoming clear that the electrophysiologic aspects of these disorders are more complex than previously realized. We review the current information available on the electrophysiologic features of the inherited demyelinating neuropathies in hopes of clarifying the clinical electrodiagnostic features of these disorders as well as to shed light on the physiologic consequences of the different genetic mutations.

The rod photoreceptor ATP-binding cassette transporter gene, ABCR, and retinal disease: from monogenic to multifactorial

The ABCR gene encodes a rod photoreceptor specific ATP-binding cassette transporter. Mutations in ABCR are associated with at least four inherited retinal dystrophies: Stargardt disease, Fundus Flavimaculatus, cone-rod dystrophy, and retinitis pigmentosa. A statistically significant increase in heterozygous ABCR alterations has been identified in patients with age-related macular degeneration (AMD). A pedigree is described which manifests both Stargardt disease and AMD in which an ABCR mutation cosegregates with both disease phenotypes. These data from this case report support the hypothesis that ABCR is a dominant susceptibility locus for AMD. Recent work regarding ABCR is reviewed and a model is presented in which decreased ABCR function correlates with severity of retinal disease.