A comparison of the ease of tracheal intubation using a McGrath MAC(®) laryngoscope and a standard Macintosh laryngoscope.

We compared the McGrath MAC(®) videolaryngoscope when used as both a direct and an indirect laryngoscope with a standard Macintosh laryngoscope in patients without predictors of a difficult tracheal intubation. We found higher median Intubation Difficulty Scores with the McGrath MAC as a direct laryngoscope, 1 (0-3 [0-5]) than when using it as an indirect videolaryngoscope, 0 (0-1 [0-5]) or when using the Macintosh laryngoscope, 0 (0-1 [0-5]), p = 0.04. This was mirrored in the subjective user reporting, scored out of 10, of difficulty for each method 3.0 (2.0-3.4 [0.5-80]); 2.0 (1.0-3.9 [0-70]) and 2.0 (1.0-3.3 [0-70]), respectively (p = 0.01). This difficulty is in part explained by the poorer laryngeal views recorded using the Cormack and Lehane classification system (p < 0.001) and reflected in the higher than normal operator force required (25%, 4%, 8% for each method, respectively, p < 0.001) and the increased use of rigid intubation aids (21%, 6%, 2%, respectively, p < 0.001). There was no difference between the groups in time taken to intubate or incidence of complications. There was no statistical difference in the performances as measured between the McGrath MAC used as an indirect videolaryngoscope and the Macintosh laryngoscope. We cannot recommend that the McGrath videolaryngoscope be used as a direct laryngscopic device in place of the Macintosh.

Studies on Synthetic and Natural Melanin and Its Affinity for Fe(III) Ion.

In this work, we measured the metal-binding sites of natural and synthetic dihydroxyindole (DHI) melanins and their respective interactions with Fe(III) ions. Besides the two acid groups detected for the DHI system: catechol (Cat) and quinone-imine (QI), acetate groups were detected in the natural oligomer by potentiometric titrations. At acidic pH values, Fe(III) complexation with synthetic melanin was detected in an Fe(OH)(CatH(2)Cat) interaction. With an increase of pH, three new interactions occurred: dihydroxide diprotonated catechol, Fe(OH)(2)(CatH(2)Cat)(-), dihydroxide monoprotonated catechol, [Fe(OH)(2)(CatHCat)](2-), and an interaction resulting from the association of one quinone-imine and a catechol group, [Fe(OH)(2)(Qi(-))(CatHCat)](3-). In the natural melanin system, we detected the same interactions involving catechol and quinone-imine groups but also the metal interacts with acetate group at pH values lower than 4.0. Furthermore, interactions in the synthetic system were also characterized by infrared spectroscopy by using the characteristic vibrations of catechol and quinone-imine groups. Finally, scanning electronic microscopy (SEM) and energy-dispersive X-ray (EDS) analysis were used to examine the differences in morphology of these two systems in the absence and presence of Fe(III) ions. The mole ratio of metal and donor atoms was obtained by the EDS analysis.

The Southwest of Scotland Structural Chromosomal Abnormalities Database: an assessment of its contribution to genetic counselling in affected families.

AIM: To assess the effect of establishing a genetic database on the provision of genetic counselling to individuals and families with structural chromosomal abnormalities. METHOD: For the four year period 1997-2000, we compared all cytogenetics laboratory records with entries on the database to determine its completeness. We assessed the extent to which families had been followed up, compared these findings with a previous four year period (1977-1980) and sought to discover why some families were not followed up. RESULTS: Of 215 probands identified during 1997-2000, 19 (9%) were not recorded on the register. Approximately one third of families were followed up completely, one third were partially followed up and one third had had no follow-up, for a variety of reasons. In this last group, there was evidence that some had received inadequate or incorrect genetic advice. There was no evidence that the database improved follow-up in families with structural chromosome abnormalities. Over 20 years, there has been a downward trend in the proportion of cases referred to the genetic clinic. CONCLUSIONS: Our register can be used to monitor trends in clinical practice but has had no direct effect on the service provided to patients and their families.

Handheld metal detector confirmation of radiopaque foreign bodies in the esophagus.

OBJECTIVE: To examine the utility of handheld metal detectors in confirming the position of radiopaque foreign bodies in the esophagus before delayed endoscopic removal. DESIGN: Prospective study of patients evaluated between June 1, 1997, and August 31, 1999. SETTING: Tertiary pediatric referral center. PATIENTS: Twenty-six of 139 children presenting consecutively for evaluation of esophageal foreign bodies met eligibility criteria and completed the study protocol. Inclusion in the study was contingent on a delay of at least 6 hours from the time of diagnosis to the time of endoscopic removal. All patients underwent both radiographic evaluation and handheld metal detector scanning of the chest and abdomen on presentation and immediately before endoscopic removal. RESULTS: All patients evaluated during the study period had coins lodged within the esophagus. Handheld metal detector scanning accurately confirmed this position before endoscopic removal in all cases. CONCLUSION: Our data suggest that handheld metal detectors may obviate the need for repeated radiographs in patients whose foreign bodies cannot be removed at presentation.

Characterization of clustered MHC-linked olfactory receptor genes in human and mouse.

Olfactory receptor (OR) loci frequently cluster and are present on most human chromosomes. They are members of the seven transmembrane receptor (7-TM) superfamily and, as such, are part of one of the largest mammalian multigene families, with an estimated copy number of up to 1000 ORs per haploid genome. As their name implies, ORs are known to be involved in the perception of odors and possibly also in other, nonolfaction-related, functions. Here, we report the characterization of ORs that are part of the MHC-linked OR clusters in human and mouse (partial sequence only). These clusters are of particular interest because of their possible involvement in olfaction-driven mate selection. In total, we describe 50 novel OR loci (36 human, 14 murine), making the human MHC-linked cluster the largest sequenced OR cluster in any organism so far. Comparative and phylogenetic analyses confirm the cluster to be MHC-linked but divergent in both species and allow the identification of at least one ortholog that will be useful for future regulatory and functional studies. Quantitative feature analysis shows clear evidence of duplications of blocks of OR genes and reveals the entire cluster to have a genomic environment that is very different from its neighboring regions. Based on in silico transcript analysis, we also present evidence of extensive long-distance splicing in the 5'-untranslated regions and, for the first time, of alternative splicing within the single coding exon of ORs. Taken together with our previous finding that ORs are also polymorphic, the presented data indicate that the expression, function, and evolution of these interesting genes might be more complex than previously thought.

Screw fixation mentoplasty.

A technique of transoral screw fixation mentoplasty is described for management of facial disproportion due to microgenia. One hundred and fifty-two patients followed for an average of 5.3 years revealed that screw fixation mentoplasty serves well to reduce perioperative morbidity and ensure a long-term improvement in facial balance and aesthetics.

MHC-linked olfactory receptor loci exhibit polymorphism and contribute to extended HLA/OR-haplotypes.

Clusters of olfactory receptor (OR) genes are found on most human chromosomes. They are one of the largest mammalian multigene families. Here, we report a systematic study of polymorphism of OR genes belonging to the largest fully sequenced OR cluster. The cluster contains 36 OR genes, of which two belong to the vomeronasal 1 (V1-OR) family. The cluster is divided into a major and a minor region at the telomeric end of the HLA complex on chromosome 6. These OR genes could be involved in MHC-related mate preferences. The polymorphism screen was carried out with 13 genes from the HLA-linked OR cluster and three genes from chromosomes 7, 17, and 19 as controls. Ten human cell lines, representing 18 different chromosome 6s, were analyzed. They were from various ethnic origins and exhibited different HLA haplotypes. All OR genes tested, including those not linked to the HLA complex, were polymorphic. These polymorphisms were dispersed along the coding region and resulted in up to seven alleles for a given OR gene. Three polymorphisms resulted either in stop codons (genes hs6M1-4P, hs6M1-17) or in a 16-bp deletion (gene hs6M1-19P), possibly leading to lack of ligand recognition by the respective receptors in the cell line donors. In total, 13 HLA-linked OR haplotypes could be defined. Therefore, allelic variation appears to be a general feature of human OR genes.

The interrelationship of subglottic air pressure, fundamental frequency, and vocal intensity during speech.

In this study we have simultaneously measured subglottic air pressure, airflow, and vocal intensity during speech in nine healthy subjects. Subglottic air pressure was measured directly by puncture of the cricothyroid membrane. The results show that the interaction between these aerodynamic properties is much more complex that previously believed. Certain trends were seen in most individuals, such as an increase in vocal intensity with increased subglottic air pressure. However, there was considerable variability in the overall aerodynamic properties between subjects and at different frequency and intensity ranges. At certain frequencies several subjects were able to generate significantly louder voices without a comparable increase in subglottic air pressure. We hypothesize that these increases in vocal efficiency are due to changes in vocal fold vibration properties. The relationship between fundamental frequency and subglottic pressure was also noted to vary depending on vocal intensity. Possible mechanisms for these behaviors are discussed.

Polymorphisms in olfactory receptor genes: a cautionary note.

The hundreds of human olfactory receptor (OR) genes are organized into clusters occurring on nearly every chromosome. Although their sequences are not always closely related, they share stretches of considerable similarity, both at the amino acid and nucleotide levels. We demonstrate here that an HLA complex-linked OR sequence, FAT11, for which recently a number of alleles have been claimed within the Hutterites, contains sequences derived from two closely related, linked OR genes, hs6M1-12 and hs6M1-16. Instead of indicating a difference between alleles of a given locus, two of the polymorphisms described for FAT11 (at amino acids 48 and 220 of the deduced protein sequence, respectively) may in fact reflect distinct sequences of hs6M1-12 and a further, closely related HLA-linked OR locus, hs6M1-13P. As a consequence, recombination rates in Hutterites in the region telomeric of HLA-G may have to be reconsidered.

Illusions in rhinoplasty.

A good rhinoplasty surgeon attempts to enhance nasal performance through airway and appearance improvement. The great rhinoplasty surgeon routinely improves not only nasal performance but endeavors to achieve a higher level of overall facial aesthetic enhancement by manipulating the surgical illusions of the face. This cohesive interplay of science between the eyes, cheeks, nose, lips, and chin is known all to well by the master facial plastic surgeon who defines the art of rhinoplasty.

Conservative subtraction-addition rhinoplasty.

The deviated external nose remains a difficult technical challenge to even the most masterful rhinoplastic surgeon. The classic septorhinoplasty approach to the deviated nose demonstrated a 9.8% revision rate in this study. During a 2-year period, the conservative subtraction-addition rhinoplasty procedure was developed, which subsequently reduced the revision rate to 1.3%. Conservative subtraction-addition rhinoplasty foregoes aggressive septal surgery and equalizes and enhances the airway through asymmetric turbinate volume reduction. Minimal bony and upper lateral work through rasping, soft tissue removal, and/or cartilage grafting allows for external nasal alignment. Both internal and external conservative subtraction-addition rhinoplasty components thus maintain perioperative structural stability and ensure long-term nasal symmetry.

The versatile melolabial flap.

The melolabial flap is a versatile technique for reconstruction of defects of the central face. Variations of this flap may be used to reconstruct the lower eyelids, the nose, the upper and lower lip, chin, and malar regions. Regional anatomy, indications, technical considerations, and avoidance of complications are discussed on the basis of 10 bilateral cadaver dissections of the melolabial area, in conjunction with 70 reconstructive cases that used this flap. Statistical analysis of the results reveals that flap viability is compromised by previous radiation and smoking. Consequently, alternate methods of reconstruction of the central face should be used in patients who have a history of these problems.

Characterization of mononuclear cell-derived histamine release enhancing factor.

Histamine release enhancing factor (HREF) is a product of phytohemagglutinin-stimulated mononuclear cells that substantially augments in vitro IgE-mediated basophil histamine release. The factor is stable at 56 degrees C and has a molecular weight in the 10,000 to 30,000 dalton range. The magnitude of HREF activity produced is dependent on the concentration of mononuclear cells cultured and the final concentration of HREF during basophil challenge. The HREF phenomenon could not be attributed to phytohemagglutinin, alpha- or gamma-interferon, arachidonic acid metabolites, or interleukin-1 or 2. HREF appears to be a unique cytokine of potential importance in the immunology of inflammatory and atopic processes.

Intravenous methylprednisolone efficacy in status asthmaticus of childhood.

Forty-nine nonsteroid-dependent children hospitalized with status asthmaticus were randomized to receive IV placebo or methylprednisolone treatment (1 mg/kg every six hours). All patients received nebulized isoetharine inhalations and continuous IV aminophylline infusion. Twenty-four hours after admission, the methylprednisolone-treated patients demonstrated a greater rate of improvement in their clinical scoring index than did placebo-treated children. However, the duration of hospital stay was not significantly shortened. Twenty-eight of the patients performed serial bedside spirometry at 0, 12, 24, and 36 hours after admission. The methyl-prednisolone-treated patients experienced a more rapid recovery from peripheral airway obstruction as measured by forced expiratory flow rate during 25% to 75% of forced vital capacity (FEF25-75). The magnitude and rate of improvement in FEF25-75 was significantly greater at 36 hours (P less than .05) and independent of changes in peak expiratory flow rate, forced vital capacity, or forced expiratory volume in the first second of forced vital capacity. Placebo-treated patients had a higher incidence of asthma relapse within 4 weeks of discharge (eight v two relapses, P less than .05). Findings of this study indicate that IV corticosteroid therapy is beneficial in treating pediatric status asthmaticus.

Characteristics of diatrizoate-induced basophil histamine release.

Factors influencing the release of histamine by basophils exposed to the radiocontrast agent diatrizoate were investigated in vitro by use of cells from healthy adult subjects with no history of radiocontrast reactions. Diatrizoate-induced release shared similarities with calcium ionophore-induced release. The response to both agents is dose dependent, enhanced by deuterium oxide, optimal at 37 degrees C, calcium dependent, and enhanced with longer reaction times. Unlike calcium ionophore, however, pretreatment of basophils with diatrizoate may also induce dose-dependent inhibition of reactivity during subsequent challenges with anti-IgE, N-formyl methionine peptide, and calcium ionophore. These findings suggest that diatrizoate may induce histamine release via a calcium ionophore-like mechanism, but other effects on cellular function probably account for its ability to inhibit basophil responsiveness.

Functional aspects of T-lymphocyte subsets in pregnancy.

Several recent reports have suggested that a decrease in circulating T helper cells may contribute to the relative immunodeficiency of pregnancy. To investigate the significance of these findings, 90 pregnant women were evaluated. The results of this study indicate that although pregnant women have a decreased proportion of T helper cells, they do have adequate T helper cell function as determined by an in vitro immunoglobulin synthesis assay and a T-lymphocyte colony-forming assay. Based on these studies it is unlikely that decreased numbers of T helper cells are primarily responsible for the immunodeficiency of pregnancy.