Halogen- and hydrogen-bonded self-assembled fibrillar networks of substituted 1,3:2,4-dibenzylidene-D-sorbitols (DBS)

Substituting the sole primary hydroxyl group of the low molecular weight organogelator (LMOG), 1,3:2,4-dibenzylidene-D-sorbitol (DBS), with a halogen atom (Cl, Br, or I; i.e., 6-Cl-DBS, 6-Br-DBS, or 6-I-DBS) drastically alters the supramolecular self-assembled fibrillar network (SAFiN) that forms when the molecules aggregate. The SAFiN varies depending on the solvent properties, impacting the role of non-covalent hydrogen- and halogen-bonding interactions along and between fibers. The halogenated DBS derivatives have more coherent crystalline fibers than DBS, with larger length-to-width aspect ratios. High-resolution synchrotron powder X-ray diffraction of each wet-state gel in toluene and DFT optimization obtained complete structures for the three halogenated DBS derivatives in their SAFiNs. The presence of a halogen atom reduces the reliance on hydrogen bonding by enabling new halogen bonding interactions that impact the self-assembly behavior, especially in solvents of higher polarity. For 6-I-DBS and 6-Br-DBS, the primary forces driving molecular self-assembly are C-H⋯π and intermolecular halogen-to-halogen interactions, and there is one unique molecule in each unit cell. However, the Cl atoms of 6-Cl-DBS are not close, and its SAFiN structures rely more on hydrogen bonding. As a result, the enhanced hydrogen bonding, electronic differences among the halogens, and spatial factors allow its unit cell to include two independent molecules of 6-Cl-DBS.

Mixed cyclo di-amino acids structured edible oils: a potential hardstock fat mimic

Pure cyclic diamino acids (CdAA) gel differently than combinations of CdAAs, altering the gelation behavior to highly-branched colloidal protein crystal networks reminiscent of traditional fat crystal networks in canola oil, making it an exciting structuring agent for unsaturated oils.

Sous Vide Cook Temperature Alters the Physical Structure and Lipid Bioaccessibility of Beef Longissimus Muscle in TIM-1

Changes in the physical states, induced with different sous vide cooking temperatures, significantly (P < 0.05) altered lipid bioaccessibility measured in the TNO-simulated gastrointestinal tract model-1 of AAA boneless beef striploin, containing the longissimus lumborum muscle. The denaturation of actin significantly correlates with the total cumulative free fatty acid (FFA) bioaccessibility, whereby the striploin cooked to 60 °C presents the maximum lipid bioaccessibility (15.8 ± 1.0%), rate constant (k_a) for FFA hydrolysis (0.087 ± 0.003 min^-1), and greatest actin denaturation enthalpy (-0.57 ± 0.06 ΔH). Thus, thermal treatments above 60 °C significantly decrease the kinetics of lipolysis (70 °C = 0.042 ± 0.002 min^-1 and 80 °C = 0.047 ± 0.002 min^-1) and the resultant total lipid bioaccessibility (70 °C = 8.6 ± 0.7 and 80 °C = 8.3 ± 0.5%). This research highlights the potential to manipulate the physical food structure to alter digestion kinetics, supporting the need to understand supramolecular structures in food and their nutritional outcomes.

Correction: Self-assembled fibrillar networks comprised of a naturally-occurring cyclic peptide—LOB3

Correction for ‘Self-assembled fibrillar networks comprised of a naturally-occurring cyclic peptide—LOB3’ by M. A. Rogers et al., RSC Adv., 2016, 6, 40765–40776.

A comprehensive perspective of food nanomaterials

Nanotechnology is a rapidly developing toolbox that provides solutions to numerous challenges in the food industry and meet public demands for healthier and safer food products. The diversity of nanostructures and their vast, tunable functionality drives their inclusion in food products and packaging materials to improve their nutritional quality through bioactive fortification and probiotics encapsulation, enhance their safety due to their antimicrobial and sensing capabilities and confer novel sensorial properties. In this food nanotechnology state-of-the-art communication, matrix materials with particular focus on food-grade components, existing and novel production techniques, and current and potential applications in the fields of food quality, safety and preservation, nutrient bioaccessibility and digestibility will be detailed. Additionally, a thorough analysis of potential strategies to assess the safety of these novel nanostructures is presented.

The influence of dietary fat and intestinal pH on calcium bioaccessibility: anin vitrostudy

In vivostudies measuring true fractional calcium (Ca) absorption have shown that dietary fat is a significant predictor of absorption and is influenced by luminal pH levels.

Surfactant concentration and type affects the removal of Escherichia coli from pig skin during a simulated hand wash

The effect of surfactant type and concentration on a bland soap formulation's ability to remove bacteria from hands remains largely unstudied. Several combinations of surfactants and water were combined to test bacterial removal efficacy using a hand-washing device (two pieces of pig skin and a mechanical motor) to simulate a hand wash. A nalidixic acid-resistant, nonpathogenic strain of Escherichia coli (ATCC 11229) was used. Two anionic surfactants, sodium lauryl sulphate and sodium stearoyl lactylate, and two nonionic surfactants, poloxamer 407 and sorbitan monostearate, each in concentrations of 2, 5 and 10% were studied. A slight positive (r²  = 0·17) but significant (P = 0·03) correlation was observed between hydrophile-lipophile balance value and mean log reduction. No correlation was observed between pH of the treatment solution and the mean log reduction (r²  = 0·05, P = 0·25). A 10% sodium lauryl sulphate mixture showed the highest log reduction (x¯ = 1·1 log CFU reduction, SD = 0·54), and was the only treatment significantly different from washing with water (P = 0·0005). There was a correlation between increasing surfactant concentrations above the critical micelle concentration, and mean microbial reduction (r²  = 0·62, P = 0·001).

SIGNIFICANCE AND IMPACT OF THE STUDY

This study characterizes the role of surfactants in removing microbes during a hand wash. Numerous studies address how surfactants support antimicrobial effect in soap, or cause irritation of skin, but no published studies show which surfactants are best for removing microbes. We used pig skin as a model for human skin and a lathering device to simulate a hand wash. A 10% sodium lauryl sulphate mixture was the only treatment significantly different from a water wash. There was a strong correlation between increasing surfactant concentrations above the critical micelle concentration and mean microbial reduction.

Advances in edible oleogel technologies - A decade in review

Trans and saturated fat replacers/substitutes have been a tremendously active area of research for the food industry. Unlike polymers used for hydrogels, oleogels utilize small, amphiphilic molecules that self-assemble via highly specific, non-covalent interactions entrapping liquid oil via capillary forces. Edible applications of oleogels have replaced the need for trans unsaturated and saturated fatty acids to structure processed foods. These innovations mitigate the use of hardstock fats that are associated with deleterious health risks and negative consumer perception. Over the past decade, oleogels have made significant strides towards emulating desired sensory traits while maintaining healthy nutritional profile of the oil. Due to the rapid advancements in the past decade, the most promising technologies will be reviewed.

Self-assembled fibrillar networks comprised of a naturally-occurring cyclic peptide—LOB3

LOB3, a naturally-occurring orbitide, is capable of self-assembling into 1D nano-fibers and ultimately 3D molecular gel networks in acetonitrile.

To gel or not to gel: correlating molecular gelation with solvent parameters

Rational design of small molecular gelators is an elusive and herculean task, despite the rapidly growing body of literature devoted to such gels over the past decade. The process of self-assembly, in molecular gels, is intricate and must balance parameters influencing solubility and those contrasting forces that govern epitaxial growth into axially symmetric elongated aggregates. Although the gelator-gelator interactions are of paramount importance in understanding gelation, the solvent-gelator specific (i.e., H-bonding) and nonspecific (dipole-dipole, dipole-induced and instantaneous dipole induced forces) intermolecular interactions are equally important. Solvent properties mediate the self-assembly of molecular gelators into their self-assembled fibrillar networks. Herein, solubility parameters of solvents, ranging from partition coefficients (log P), to Henry's law constants (HLC), to solvatochromic parameters (ET(30)), and Kamlet-Taft parameters (β, α and π), and to Hansen solubility parameters (δp, δd, δh), are correlated with the gelation ability of numerous classes of molecular gelators. Advanced solvent clustering techniques have led to the development of a priori tools that can identify the solvents that will be gelled and not gelled by molecular gelators. These tools will greatly aid in the development of novel gelators without solely relying on serendipitous discoveries. These tools illustrate that the quest for the universal gelator should be left in the hands of Don Quixote and as researchers we must focus on identifying gelators capable of gelling classes of solvents as there is likely no one gelator capable of gelling all solvents.

Micro-viscosity of liquid oil confined in colloidal fat crystal networks

Molecular rotors may be utilized as non-invasive, non-disruptive and highly sensitive alternatives to conventional measures of bulk viscosity when the oil is entrained in a colloidal fat crystal network. Oil viscosity changes based on the molecular confinement of the oil, which is dependent on its molecular volume. Changes in micro-viscosity were not dependent on the solids content, but instead were strongly dependent on the box-counting fractal dimension in high-space filling colloidal fat crystal networks (i.e., D > 1.89). A bulk oil viscosity is often an overestimation of the actual viscosity of the entrained oil and may not be appropriate when predicting diffusion in multi-phase materials.

Influence of emulsifier structure on lipid bioaccessibility in oil-water nanoemulsions

The influence of several nonionic surfactants (Tween-20, Tween-40, Tween-60, Span-20, Span-60, or Span-80) and anionic surfactants (sodium lauryl sulfate, sodium stearoyl lactylate, and sodium stearyl fumarate) showed drastic differences in the rank order of lipase activity/lipid bioaccessibility. The biophysical composition of the oil and water interface has a clear impact on the bioaccessibility of fatty acids (FA) by altering the interactions of lipase at the oil-water interface. It was found that the bioaccessibility was positively correlated with the hydrophilic/lipophilic balance (HLB) of the surfactant and inversely correlated to the surfactant aliphatic chain length. Furthermore, the induction time in the jejunum increased as the HLB value increased and decreased with increasing aliphatic chain length. The rate of lipolysis slowed in the jejunum with increasing HLB and with increasing aliphatic chain length.

Inter-limb Coupling in Coordinated Bimanual Movement: Attention and Asymmetries

Inter-limb coupling, a phenomenon whereby each of the upper limbs tends to take on characteristics of the intended movement of the other, represents a limitation on the ability to perform asymmetrical bimanual movements. Two experiments each employing 16 dextral and 16 sinistral normal subjects are reported. In the first experiment evidence of inter-limb coupling was observed during a continuous bimanual rotary task. This coupling appeared to be asymmetrical, with the nonpreferred hand contributing more to coupling than the preferred hand, especially in dextrals. In the second experiment asymmetries in inter-limb coupling were found to be modified by the conscious direction of attention to one or other hand. This suggests that the often reported strong inter-limb asymmetry associated with dextrality, and the weaker assymetry associated with sinistrality, may be partly due to an underlying inter-limb attentional asymmetry in the former, and a relative lack of attentional asymmetry in the latter.

Pili annulati: refinement of the locus on chromosome 12q24.33 to a 2.9-Mb interval and candidate gene analysis

BACKGROUND

Pili annulati is an autosomal dominant hair shaft disorder characterized by alternating light and dark bands in hairs of affected individuals. Recently, a locus for pili annulati was mapped to chromosome 12q24.32-24.33 and recombination events defined a critical region of 9.2 cM (3.9 Mb).

OBJECTIVES

The aim of the current study was to narrow the size of the candidate region and to identify the pathogenic mutation for pili annulati by analysing the candidate genes.

METHODS

In three families with 90 individuals, including 40 affected subjects, linkage analysis was performed with 13 microsatellite markers in the candidate region on chromosome 12. Candidate genes were analysed for their expression in hair follicles and other tissues by reverse transcriptase-polymerase chain reaction (RT-PCR) and mutation analysis.

RESULTS

Multipoint LOD score analysis for all three families confirmed the locus on the long arm of chromosome 12 with a maximum LOD score of 12.26 at marker D12S357. In two families, recombinations were identified which narrowed the region to 2.9 Mb containing 36 genes. We analysed the candidate genes in this region by RT-PCR and found that 24 were expressed in human hair follicles. Based on the result of the expression analysis, DNA sequencing of the coding region of the candidate genes was performed; this did not result in the discovery of a causal mutation.

CONCLUSION

We reduced the critical interval of pili annulati to 2.9 Mb and excluded mutations in the coding region of all 36 possible candidate genes by sequence analysis.

Association between mitochondrial DNA 10398A>G polymorphism and the volume of amygdala

Mitochondrial calcium regulation plays a number of important roles in neurons. Mitochondrial DNA (mtDNA) is highly polymorphic, and its interindividual variation is associated with various neuropsychiatric diseases and mental functions. An mtDNA polymorphism, 10398A>G, was reported to affect mitochondrial calcium regulation. Volume of hippocampus and amygdala is reportedly associated with various mental disorders and mental functions and is regarded as an endophenotype of mental disorders. The present study investigated the relationship between the mtDNA 10398A>G polymorphism and the volume of hippocampus and amygdala in 118 right-handed healthy subjects. The brain morphometry using magnetic resonance images employed both manual tracing volumetry in the native space and voxel-based morphometry (VBM) in the spatially normalized space. Amygdala volume was found to be significantly larger in healthy subjects with 10398A than in those with 10398G by manual tracing, which was confirmed by the VBM. Brain volumes in the other gray matter regions and all white matter regions showed no significant differences associated with the polymorphism. These provocative findings might provide a clue to the complex relationship between mtDNA, brain structure and mental disorders.

Phase I trial of intravesical Suramin in recurrent superficial transitional cell bladder carcinoma

Suramin is an antitrypanosomal agent with antineoplastic activity, but with serious systemic side effects. We administered Suramin intravesically to determine a concentration with low toxicity but with evidence of a pharmacodynamic effect, to recommend a dose level for phase II trials. This was an open-labelled, nonrandomised dose-escalation phase I study. In all, 12 patients with a history of recurrent superficial bladder cancer were grouped into four dose levels (10–150 mg ml⁻¹ in 60 ml saline). Six catheter instillations at weekly intervals were used. Cystoscopy and biopsy were performed before and 3 months after the start of treatment. Suramin was assayed using high-performance liquid chromatography, vascular endothelial growth factor (VEGF) using ELISA (enzyme-linked immunosorbent assay), and urinary protein profile using surface-enhanced laser desorption ionisation mass spectroscopy (SELDI). Minimal systemic absorption of Suramin was found at the highest dose of 150 mg ml⁻¹. Urinary VEGF was affected by Suramin at doses above 50 mg ml⁻¹, corresponding to the estimated threshold of saturation of Suramin binding to urine albumin. SELDI showed a specific disappearance of urinary protein peaks during treatment. Intravesical Suramin shows lack of toxicity and low systemic absorption. The results of this phase I trial support expanded clinical trials of efficacy at a dose of 100 mg ml⁻¹ intravesically.

Response selection deficits in melancholic but not nonmelancholic unipolar major depression

One consistent functional imaging finding from patients with major depression has been abnormality of the anterior cingulate cortex (ACC). Hypoperfusion has been most commonly reported, but some studies suggest relative hyperperfusion is associated with response to somatic treatments. Despite these indications of the possible importance of the ACC in depression there have been relatively few cognitive studies ACC function in patients with major depression. The present study employed a series of reaction time (RT) tasks involving selection with melancholic and nonmelancholic depressed patients, as well as age-matched controls. Fifteen patients with unipolar major depression (7 melancholic, 8 nonmelancholic) and 8 healthy age-matched controls performed a series of response selection tasks (choice RT, spatial Stroop, spatial stimulus-response compatibility (SRC), and a combined Stroop + SRC condition). Reaction time and error data were collected. Melancholic patients were significantly slower than controls on all tasks but were slower than nonmelancholic patients only on the Stroop and Stroop + SRC conditions. Nonmelancholic patients did not differ from the control group on any task. The Stroop task seems crucial in differentiating the two depressive groups, they did not differ on the choice RT or SRC tasks. This may reflect differential task demands, the SRC involved symbolic manipulation that might engage the dorsal ACC and dorsolateral prefrontal cortex (DLPFC) to a greater extent than the, primarily inhibitory, Stroop task which may engage the ventral ACC and orbitofrontal cortex (OFC). This might suggest the melancholic group showed a greater ventral ACC-OFC deficit than the nonmelancholic group, while both groups showed similar dorsal ACC-DLPFC deficit.

Attentional asymmetries following ECT in patients with major depression

Neuropsychological abnormalities of lateralization have been reported after right unilateral electroconvulsive therapy (ECT), that may reflect temporary disruption of the treated hemisphere. A visuospatial task sensitive to lateralization of spatial attention was administered in a test-retest design to patients with unipolar major depression and a group of age and gender matched controls. The patient group underwent right unilateral ECT between the two test sessions. The patient and control groups did not differ significantly at the initial baseline testing. After ECT, the patient group showed a significant shift of attentional bias toward the left, while the control group showed no significant shift in the second session relative to the first. The results suggest that approximately 1 h after termination of ictus there is a leftward attentional bias, possibly reflecting a change in right hemisphere cerebral activity.

Mental rotation in unipolar major depression

Mental rotation (MR) performance may be used as an index of mental slowing or bradyphrenia, and may reflect, in particular, speed of motor preparation. MR was employed with a sample of both melancholic (n=8) and non-melancholic (n=9) unipolar depressed patients and healthy controls (n=10) to determine if motor slowing associated with depression might be reflected in slowed motor preparation (as reflected in slope of the MR function) independent of actual motor slowing (overall response time). Both melancholic and non-melancholic patients showed a generalised slowing relative to controls, perhaps reflecting bradykinesia and akinesia. This effect was significantly greater in the melancholic group than in the non-melancholic group. Relative to both the controls and the non-melancholic groups, the melancholic patients showed a progressive slowing with increasing angle of orientation indicating a specific slowing of MR. This deficit suggests a role of slowed motor planning in the psychomotor retardation of patients with melancholic depression.

The catalog of human hair keratins. II. Expression of the six type II members in the hair follicle and the combined catalog of human type I and II keratins

The human type II hair keratin subfamily consists of six individual members and can be divided into two groups. The group A members hHb1, hHb3, and hHb6 are structurally related, whereas group C members hHb2, hHb4, and hHb5 are rather distinct. Specific antisera against the individual hair keratins were used to establish the two-dimensional catalog of human type II hair keratins. In this catalog, hHb5 showed up as a series of isoelectric variants, well separated from a lower, more acidic, and complex protein streak containing isoelectric variants of hair keratins hHb1, hHb2, hHb3, and hHb6. Both in situ hybridization and immunohistochemistry on anagen hair follicles showed that hHb5 and hHb2 defined early stages of hair differentiation in the matrix (hHb5) and cuticle (hHb5 and hHb2), respectively. Although cuticular differentiation proceeded without the expression of further type II hair keratins, cortex cells simultaneously expressed hHb1, hHb3, and hHb6 at an advanced stage of differentiation. In contrast, hHb4, which is undetectable in hair follicle extracts and sections, could be identified as the largest and most alkaline member of this subfamily in cytoskeletal extracts of dorsal tongue. This hair keratin was localized in the posterior compartment of the tongue filiform papillae. Comparative analysis of type II with the previously published type I hair keratin expression profiles suggested specific, but more likely, random keratin-pairing principles during trichocyte differentiation. Finally, by combining the previously published type I hair keratin catalog with the type II hair keratin catalog and integrating both into the existing catalog of human epithelial keratins, we present a two-dimensional compilation of the presently known human keratins.

Home monitoring service improves mean arterial pressure in patients with essential hypertension. A randomized, controlled trial

BACKGROUND

Technological advances in the distribution of information have opened new avenues for patient care. Few trials, however, have used telemedicine to improve blood pressure in patients with essential hypertension.

OBJECTIVE

To determine the efficacy of a telecommunication service in reducing blood pressure.

DESIGN

Randomized, controlled trial.

SETTING

University-affiliated primary care outpatient clinics.

PATIENTS

121 adults with essential hypertension who were under evaluation for a change in antihypertensive therapy.

INTERVENTION

A home service consisting of automatic transmission of blood pressure data over telephone lines, computerized conversion of the information into report forms, and weekly electronic transmission of the report forms to physicians and patients.

MEASUREMENTS

24-hour ambulatory blood pressure monitoring at baseline and exit. The primary end point was change in mean arterial pressure from baseline to exit.

RESULTS

Mean arterial pressure decreased by 2.8 mm Hg in patients receiving the home service and increased by 1.3 mm Hg in patients receiving usual care (P = 0.013 for the difference). Mean diastolic blood pressure decreased by 2.0 mm Hg for home service but increased by 2.1 mm Hg for usual care (P = 0.012 for the difference). Mean systolic blood pressure decreased by 4.9 mm Hg for home service and 0.1 mm Hg for patients receiving usual care (P = 0.047 for the difference). Among African-American patients, mean arterial pressure decreased by 9.6 mm Hg in those receiving home service and increased by 5.25 mm Hg in those receiving usual care (P = 0.047). Part of the decrease in blood pressure for home service was due to more frequent changes in the type or dose of antihypertensive medications.

CONCLUSION

This telecommunication service was efficacious in reducing the mean arterial pressure of patients with established essential hypertension.

Characterization of a cluster of human high/ultrahigh sulfur keratin-associated protein genes embedded in the type I keratin gene domain on chromosome 17q12-21

Low stringency screening of a human P1 artificial chromosome library using a human hair keratin-associated protein (hKAP1.1A) gene probe resulted in the isolation of six P1 artificial chromosome clones. End sequencing and EMBO/GenBank(TM) data base analysis showed these clones to be contained in four previously sequenced human bacterial artificial chromosome clones present on chromosome 17q12-21 and arrayed into two large contigs of 290 and 225 kilobase pairs (kb) in size. A fifth, partially sequenced human bacterial artificial chromosome clone data base sequence overlapped and closed both of these contigs. One end of this 600-kb cluster harbored six gene loci for previously described human type I hair keratin genes. The other end of this cluster contained the human type I cytokeratin K20 and K12 gene loci. The center of the cluster, starting 35 kb downstream of the hHa3-I hair keratin gene, contained 37 genes for high/ultrahigh sulfur hair keratin-associated proteins (KAPs), which could be divided into a total of 7 KAP multigene families based on amino acid homology comparisons with previously identified sheep, mouse, and rabbit KAPs. To date, 26 human KAP cDNA clones have been isolated through screening of an arrayed human scalp cDNA library by means of specific 3'-noncoding region polymerase chain reaction probes derived from the identified KAP gene sequences. This screening also yielded four additional cDNA sequences whose genes were not present on this gene cluster but belonged to specific KAP gene families present on this contig. Hair follicle in situ hybridization data for single members of five different KAP multigene families all showed localization of the respective mRNAs to the upper cortex of the hair shaft.

Skeletal muscle satellite cell characteristics in young and older men and women after heavy resistance strength training

Skeletal muscle satellite cell proportions and morphology were assessed in healthy, sedentary young and older men and women in response to heavy resistance strength training (HRST). Fourteen young (20-30 years) men (n = 7) and women (n = 7) and 15 older (65-75 years) men (n = 8) and women (n = 7) completed 9 weeks of unilateral knee extension exercise training 3 days per week. Muscle biopsies were obtained from each vastus lateralis before and after training, with the nondominant leg serving as an untrained control. All four groups demonstrated a significant increase in satellite cell proportion in response to HRST (2.3 +/- 0.4% vs 3.1 +/- 0.4% for all subjects combined, before and after training, respectively; p < .05), with older women demonstrating the greatest increase (p < .05). Morphology data indicated a significant increase in the proportion of active satellite cells in after-training muscle samples compared with before-training samples and with control leg samples (31% vs 6% and 7%, respectively; p < .05). The present results indicate that the proportion of satellite cells is increased after HRST in young and older men and women, with an exaggerated response in older women. Furthermore, the proportion of satellite cells that appear morphologically active is increased as a result of HRST.

Bimanual coordination in chronic schizophrenia

Anomalies of movement are observed both clinically and experimentally in schizophrenia. While the basal ganglia have been implicated in its pathogenesis, the nature of such involvement is equivocal. The basal ganglia may be involved in bimanual coordination through their input to the supplementary motor area (SMA). While a neglected area of study in schizophrenia, a bimanual movement task may provide a means of assessing the functional integrity of the motor circuit. Twelve patients with chronic schizophrenia and 12 matched control participants performed a bimanual movement task on a set of vertically mounted cranks at different speeds (1 and 2 Hz) and phase relationships. Participants performed in-phase movements (hands separated by 0 degrees ) and out-of-phase movements (hands separated by 180 degrees ) at both speeds with an external cue on or off. All participants performed the in-phase movements well, irrespective of speed or cueing conditions. Patients with schizophrenia were unable to perform the out-of-phase movements, particularly at the faster speed, reverting instead to the in-phase movement. There was no effect of external cueing on any of the movement conditions. These results suggest a specific problem of bimanual coordination indicative of SMA dysfunction per se and/or faulty callosal integration. A disturbance in the ability to switch attention during the out-of-phase task may also be involved.

A novel type II cytokeratin, mK6irs, is expressed in the Huxley and Henle layers of the mouse inner root sheath

Hair follicle differentiation involves the expression of both epithelial-type keratins or cytokeratins and hair keratins as well as hair keratin-associated proteins. In this study, a cDNA clone encoding a cytokeratin family member was isolated using RNA differential display techniques. The predicted amino acid sequence derived from this clone, revealed a homology with a number of cytokeratins, not only in the central alpha-helical regions but also in the conserved portions of the amino and carboxy terminal domains, indicating that this protein represents a new member of the mouse type II cytokeratin family. Northern blot analysis showed expression in mouse skin, but not in other tissues, including tongue, esophagus, and forestomach. One- and two-dimensional western blot analysis showed that this new cytokeratin was 57 kDa in size and ran slightly below the area of cytokeratin 5, which corresponded to that of the cytokeratin 6 family members. Both RNA in situ hybridization and immunohistochemical studies of mouse anagen hair follicles demonstrated expression of this cytokeratin in the inner root sheath hair cone during anagen III and in the Henle and Huxley layers of the inner root sheath during anagen VI. The expression of the new cytokeratin began in the hair bulb and progressed up to the height of the keratogenous zone. Taken together the sum of the data analyzed, we have termed this novel cytokeratin mK6irs (mouse gene nomenclature k2-6g) to indicate both its similar mobility with K6 in two-dimensional gels and its specific expression in the inner root sheath of the hair follicle.

Treating benign colon disorders using laparoscopic colectomy

Laparoscopic bowel surgery is a recent application of minimally invasive videoscopic techniques. Understanding the anatomy and physiology of the bowel, the background of bowel disorders and their treatment, signs and symptoms of bowel disease, and the patient selection process can help perioperative nurses better care for patients diagnosed with colon polyps, diverticulitis, and inflammatory bowel disease.

Searching for clinical prediction rules in MEDLINE

OBJECTIVES

Clinical prediction rules have been advocated as a possible mechanism to enhance clinical judgment in diagnostic, therapeutic, and prognostic assessment. Despite renewed interest in the their use, inconsistent terminology makes them difficult to index and retrieve by computerized search systems. No validated approaches to locating clinical prediction rules appear in the literature. The objective of this study was to derive and validate an optimal search filter for retrieving clinical prediction rules, using the National Library of Medicine's MEDLINE database.

DESIGN

A comparative, retrospective analysis was conducted. The "gold standard" was established by a manual search of all articles from select print journals for the years 1991 through 1998, which identified articles covering various aspects of clinical prediction rules such as derivation, validation, and evaluation. Search filters were derived, from the articles in the July through December issues of the journals (derivation set), by analyzing the textwords (words in the title and abstract) and the medical subject heading (from the MeSH Thesaurus) used to index each article. The accuracy of these filters in retrieving clinical prediction rules was then assessed using articles in the January through June issues (validation set).

MEASUREMENTS

The sensitivity, specificity, positive predictive value, and positive likelihood ratio of several different search filters were measured.

RESULTS

The filter "predict$ OR clinical$ OR outcome$ OR risk$" retrieved 98 percent of clinical prediction rules. Four filters, such as "predict$ OR validat$ OR rule$ OR predictive value of tests," had both sensitivity and specificity above 90 percent. The top-performing filter for positive predictive value and positive likelihood ratio in the validation set was "predict$.ti. AND rule$."

CONCLUSIONS

Several filters with high retrieval value were found. Depending on the goals and time constraints of the searcher, one of these filters could be used.

Human type I hair keratin pseudogene phihHaA has functional orthologs in the chimpanzee and gorilla: evidence for recent inactivation of the human gene after the Pan-Homo divergence

In addition to nine functional genes, the human type I hair keratin gene cluster contains a pseudogene, phihHaA (KRTHAP1), which is thought to have been inactivated by a single base-pair substitution that introduced a premature TGA termination codon into exon 4. Large-scale genotyping of human, chimpanzee, and gorilla DNAs revealed the homozygous presence of the phihHaA nonsense mutation in humans of different ethnic backgrounds, but its absence in the functional orthologous chimpanzee (cHaA) and gorilla (gHaA) genes. Expression analyses of the encoded cHaA and gHaA hair keratins served to highlight dramatic differences between the hair keratin phenotypes of contemporary humans and the great apes. The relative numbers of synonymous and non-synonymous substitutions in the phihHaA and cHaA genes, as inferred by using the gHaA gene as an outgroup, suggest that the human hHaA gene was inactivated only recently, viz., less than 240,000 years ago. This implies that the hair keratin phenotype of hominids prior to this date, and after the Pan-Homo divergence some 5.5 million years ago, could have been identical to that of the great apes. In addition, the homozygous presence of the phihHaA exon 4 nonsense mutation in some of the earliest branching lineages among extant human populations lends strong support to the "single African origin" hypothesis of modern humans.

Skeletal muscle satellite cell populations in healthy young and older men and women

The purpose of the present investigation was to assess satellite cell populations and morphology in m. vastus lateralis biopsies obtained from young (20-30 years) and older (65-75 years) healthy, sedentary men and women. Multiple muscle biopsies were obtained from 14 young individuals (men, n = 7; women, n = 7) and 15 older individuals (men, n = 8; women, n = 7). Muscle fibers were viewed longitudinally using a Zeiss EM 10 CA electron microscope. All myonuclei and satellite cells were counted and satellite cells were photographed for morphological analysis. The proportion of satellite cells [satellite cells/(myonuclei + satellite cells)] did not differ among the four subject groups (1.7-2.8%), nor did proportions differ when subject groups were combined for age and gender comparisons. Few morphological differences were noted between groups; however, lipofuscin granules were more prominent in satellite cells from older subjects and women demonstrated significantly larger satellite cell and satellite cell nucleus areas than men. Mitochondria from satellite cells (regardless of group) were more pallid and exhibited fewer cristae than mitochondria located in the adjacent muscle fiber. The results of the current investigation suggest that, despite findings in animal models, satellite cell populations are not significantly lower in healthy, sedentary older compared to young adult men and women.

Skeletal muscle satellite cell populations in healthy young and older men and women

The purpose of the present investigation was to assess satellite cell populations and morphology in m. vastus lateralis biopsies obtained from young (20-30 years) and older (65-75 years) healthy, sedentary men and women. Multiple muscle biopsies were obtained from 14 young individuals (men, n = 7; women, n = 7) and 15 older individuals (men, n = 8; women, n = 7). Muscle fibers were viewed longitudinally using a Zeiss EM 10 CA electron microscope. All myonuclei and satellite cells were counted and satellite cells were photographed for morphological analysis. The proportion of satellite cells [satellite cells/(myonuclei + satellite cells)] did not differ among the four subject groups (1.7-2.8%), nor did proportions differ when subject groups were combined for age and gender comparisons. Few morphological differences were noted between groups; however, lipofuscin granules were more prominent in satellite cells from older subjects and women demonstrated significantly larger satellite cell and satellite cell nucleus areas than men. Mitochondria from satellite cells (regardless of group) were more pallid and exhibited fewer cristae than mitochondria located in the adjacent muscle fiber. The results of the current investigation suggest that, despite findings in animal models, satellite cell populations are not significantly lower in healthy, sedentary older compared to young adult men and women.

Muscle biopsy and muscle fiber hypercontraction: a brief review

The percutaneous muscle biopsy technique is an important tool used in exercise and applied physiology to study human skeletal muscle structure, adaptation, and regeneration. One important use of this technique has been the assessment of ultrastructural muscle damage, especially in tissue samples obtained following strenuous exercise protocols, often involving eccentric muscle actions. In this brief review, we define and describe hypercontracted fibers, and outline how such fibers may adversely affect the interpretation of muscle damage from fixed tissue. Evidence suggests that hypercontracted fibers present in healthy skeletal muscle samples are likely to be artifacts related to the muscle biopsy procedure, as opposed to intrinsic degeneration present prior to the biopsy. When hypercontracted fibers are noted as being intrinsic to a muscle sample (e.g., in myopathy or following an extreme eccentric stimulus), such fibers are generally associated with the infiltration of inflammatory cells, indicative of a regenerative response. In contrast, hypercontracted fibers resulting from the biopsy procedure are not typically associated with an inflammatory response. The major sources of hypercontracted fibers are outlined and recommendations for their interpretation are discussed.

Treatment of latent tuberculosis infection in patients aged > or =35 years

Treating patients aged > or =35 years for tuberculosis infection has been controversial because of the hepatotoxic effects of isoniazid. A 2-year retrospective cohort study of outpatient medical records determined the completion rate in this age group and identified risk factors associated with isoniazid-associated hepatotoxicity. Isoniazid preventative therapy was well tolerated. However, toxicity occurred in women receiving concomitant medications and men who used alcohol.

Oestrogen receptor expression in normal breast epithelium

Higher levels of oestrogen receptor (ER) expression in normal breast epithelium may compound the increase in breast cancer risk seen with prolonged estrogen exposure. In prior studies, we have used immunohistochemical ER assays on fresh frozen samples of benign breast tissue. Future studies will be more feasible on paraffin-embedded samples, and newer, more sensitive antibodies are now available. We examined 30 samples of paraffin-embedded breast epithelium from postmenopausal women with two antibodies, 6F11 and TE111. We find that the median labelling indices for ER are significantly higher using these antibodies, compared with previous results. The threshold for ER positivity will, therefore, have to be reset in future studies, since there are still many issues that remain to be resolved in this area.

Reliance on external cues during serial sequential movement in major depression

Maintenance of motor set in patients with unipolar major depression was examined. Twelve melancholic and 12 non-melancholic depressed patients and 24 age matched controls performed a serial choice reaction time task while external cues aiding maintenance of a motor set were systematically removed. Melancholic patients were significantly slower than controls with no reduction in external cues and with a moderate reduction in external cues. At a high level of reduction in external cues, seven of 12 melancholic patients (but only three of 12 non-melancholic patients and controls) were unable to complete the task; suggesting a greater reliance on external cues, perhaps implicating a failure of motor planning ability in melancholic patients. This, in turn, may point to a prefrontal (premotor) deficit in melancholic depression, with possible commonalities with Parkinson's disease.

Limited utility of routine drug screening in trauma patients

BACKGROUND

Routine toxicology screening of seriously injured patients has become the standard of care in most trauma centers. However, the benefit of drug screening in acute trauma is unproven. We reviewed the impact of positive drug screening results on patient care within the first 3 days of treatment.

METHODS

We retrospectively reviewed the charts of seriously injured patients admitted to an American College of Surgeons-certified level I trauma center over a 5-year period. Modifications of therapeutic regimens based on positive toxicology results were noted. Using current financial data, charges for toxicology were calculated.

RESULTS

Between January 1, 1990, and December 31, 1995, 2,678 trauma patients had drug screening. Of these, 414 (15%) had detectable quantities of the following intoxicants: opiates, barbiturates, amphetamines, phencyclidine hydrochloride (PCP), cocaine, marijuana, or benzodiazepines. Review of all 401 available charts failed to identify any cases in which treatment was altered by a positive toxicology result. Hospital costs related to routine screening were $138,587, while charges to patients amounted to $538,278.

CONCLUSIONS

Routine toxicology does not alter or improve the immediate care of the injured patient. Routine drug screening is expensive, and benefits were not easily documented. The policy of routine toxicology screening in trauma centers should be reevaluated.

Parkinsonian motor characteristics in unipolar major depression

Clinical observation points to similarities between psychomotor retardation in major depression and bradykinesia in Parkinson's disease (PD). While common elements of neuropathology have been proposed to account for this, experimental investigations of this possible link have been few and inconclusive. The present study attempts to determine whether patients with depression display the characteristically Parkinsonian reliance on external cues; and if so, whether this is common to both melancholic and non-melancholic patients. Twenty three patients with unipolar major depression (11 melancholic and 12 non-melancholic) and 24 age-matched healthy controls performed a serial choice reaction time task known to be sensitive to Parkinsonian movement deficits. The melancholic patients showed a Parkinsonian pattern of impairment on the task, exhibiting a particular difficulty when initiating movements in the absence of external cues. This was largely alleviated when a moderate amount of external cueing was provided. At a high level of advance information, melancholic patients were again slow relative to controls. A base-line measure of bradykinesia and a derived measure of dependence upon external cues both correlated significantly with CORE (measure of psychomotor disturbance) ratings. The non-melancholic patients did not show any measurable motor impairment. This cue-dependent deficit may be due to an underlying basal ganglia dysfunction similar to that involved in PD, i.e. a failure of internal cueing. Difficulty with a high level of external cueing might reflect bradyphrenia or a prefrontal motor deficit of ability to plan multiple upcoming movements simultaneously. The results suggest that depression subtypes involve differing patterns of fronto-striatal impairment.

High-volume, heavy-resistance strength training and muscle damage in young and older women

To determine possible age differences in muscle damage response to strength training, ultrastructural muscle damage was assessed in seven 20- to 30-yr-old and six 65- to 75-yr-old previously sedentary women after heavy-resistance strength training (HRST). Subjects performed unilateral knee-extension exercise 3 days/wk for 9 wk. Bilateral muscle biopsies from the vastus lateralis were assessed for muscle damage via electron microscopy. HRST resulted in a 38 and 25% increase in strength in the young and older women, respectively (P < 0.05), but there were no between-group differences. In the young women, 2-4% of muscle fibers exhibited damage before and after training in both the trained and untrained legs (P = not significant). In contrast, muscle damage increased significantly after HRST, from 5 to 17% of fibers damaged (P < 0.01), in the older women in the trained leg compared with only 2 and 5% of fibers damaged in the untrained leg before and after training, respectively. The present results indicate that older women exhibit higher levels of muscle damage after chronic HRST than do young women.

Characterization of a 300 kbp region of human DNA containing the type II hair keratin gene domain

Screening of an arrayed human genomic P1 artificial chromosome DNA library by means of the polymerase chain reaction with a specific primer pair from the human type II hair keratin hHb5 yielded two P1 artificial chromosome clones covering approximately 300 kb of genomic DNA. The contig contained six type II hair keratin genes, hHb1-hHb6, and four keratin pseudogenes psihHbA-psihHbD. This hair keratin gene domain was flanked by type II epithelial keratins K6b/K6hf and K7, respectively. The keratin genes/pseudogene are 5-14 kbp in size with intergenic distances of 5-19 kbp of DNA and do not exhibit a single direction of transcription. With one exception, type II hair keratin genes are organized into nine exons and eight introns, with strictly conserved exon-intron boundaries. The functional hair keratin genes are grouped into two distinct subclusters near the extremities of the hair keratin gene domain. One subcluster encodes the highly related hair keratins hHb1, hHb3, and hHb6; The second cluster encodes the structurally less related hair keratins hHb2, hHb4, and hHb5. Reverse transcription-polymerase chain reaction shows that all hair keratin genes are expressed in the hair follicle. Pseudogene psihHbD is also transcriptionally expressed, albeit with alterations in splicing and frameshift mutations, leading to premature stop codons in the splice forms analyzed. Evolutionary tree analysis revealed a divergence of the type II hair keratin genes from the epithelial keratins, followed by their segregation into the members of the two subclusters over time. We assume that the approximately 200 kbp DNA domain contains the entire complement of human type II hair keratin genes.