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PubMed1995

The validity of maxillary expansion indices.

Numerous indices have been proposed to help the clinician decide how much maxillary expansion will be required to alleviate crowding. The purpose of this investigation was to examine the validity of Pont's index, Schwarz's analysis and McNamara's rule of thumb. Records of 40 patients (20 females and 20 males) were selected from 155 consecutive pretreatment records. The discrepancy between actual intermolar/interpremolar widths and the index-generated widths were correlated against measures of crowding, and linear regressions were computed. Statistical analysis revealed that (1) males had more significant correlations between arch width and crowing than females, (2) interpremolar widths were more strongly correlated than intermolar widths, (3) Pont's index and McNamara's rule of thumb overestimated required arch width by 2.5 mm to 4.7 mm and 2.7 mm to 3.7 mm respectively, and (4) Schwarz's analysis overestimated interpremolar width by 2.5 mm to 4.3 mm but was reasonably accurate for intermolar width in males. The results suggest that these indices potentially overestimate the arch expansion required to alleviate crowding.

Bicuspid↗
PubMed2000

Concerns of speech-impaired people and those communicating with them.

This study investigated the perception and experiences of people with speech impairments and of the general public when communicating with speech impaired people. The aim was to identify the actual concerns of people and factors that make communication easier or more difficult, to inform treatment programmes and information. A triangulated approach was used. Discussion groups were held with members of the public, in-depth interviews were conducted with speech-impaired people and an experimental study examined encounters between speech-impaired people and shop workers. In a partial replication of the work of Crow (1988) the views of speech-impaired people were elicited by a questionnaire. Concerns identified in group discussions related to the importance of time and the need for information. The experiment suggested that the type of speech impairment might influence attitudes. Findings from the questionnaire and the interviews emphasized the importance of taking time and being assertive. The limitations of the findings and the possible service implications are discussed.

Journal Article↗
PubMed2002

Evaluating the effect of stage-specific survivorship on the N(e)/N ratio.

Evaluating effective population size (Ne) and the effective size to census size ratio (Ne/N) in species with Type III survivorship curves is complicated when key demographic parameters [mean (k macro) and variance (V(k)) of family size] are measured during early life stages. The method of Crow & Morton (1955) for scaling demographic data collected at a juvenile stage to expected values at adulthood is extended to consider sequential episodes of random and family correlated survival. Results show the following: (i) The order in which the episodes of random and family-correlated survival occur does not affect N(e) or N(e)/N; (ii) If a population experiences an episode of family-correlated survival, N(e)/N scaled to its expected value in a population of constant size (k macro= 2) is simply the survival rate during the family-correlated stage. If multiple such stages occur, scaled N(e)/N is the product of the survivals during all family-correlated life stages; (iii) Under the assumption of random post-enumeration survival, adjusting the variance effective size to its expected value at k macro= 2 is equivalent to computing the inbreeding effective size at the earlier life stage. Application to experimental data for hatchery populations of Pacific salmon (Oncorhynchus spp.) indicates that nonrandom survival during the marine phase led to estimated reductions in effective size of 0-62 (mean 19) in 12 different cohorts. This approach can provide insights into N(e)/N in highly fecund species, including some marine species in which N(e) has been estimated to be several orders of magnitude less than N.

Animals↗
PubMed2003

Estimating effective paternity number in social insects and the effective number of alleles in a population.

Estimating paternity and genetic relatedness is central to many empirical and theoretical studies of social insects. The two important measures of a queen's mating number are her actual number of mates and her effective number of mates. Estimating the effective number of mates is mathematically identical to the problem of estimating the effective number of alleles in population genetics, a common measure of genetic variability introduced by Kimura & Crow (1964). We derive a new bias-corrected estimator of effective number of types (mates or alleles) and compare this new method to previous methods for estimating true and effective numbers of types using Monte Carlo simulations. Our simulation results suggest that the examined estimators of the true number of types have very similar statistical properties, whereas the estimators of effective number of types have quite different statistical properties. Moreover, our new proposed estimator of effective number of types is approximately unbiased, and has considerably lower variance than the original estimator. Our new method will help researchers more accurately estimate intracolony genetic relatedness of social insects, which is an important measure in understanding their ecology and social behaviour. It should also be of use in population genetic studies in which the effective number of alleles is of interest.

Alleles↗
PubMed2003

Pathological effects of formalin (37% formaldehyde) mixed in feed or administered into the crops of White Leghorn cockerels.

This study compared the adverse effects of formalin administered by two different methods. Formalin mixed with the feed (2.5, 5.0 and 10 ml/kg) was given to 10-week-old White Leghorn cockerels for a period of 8 weeks. Simultaneously in other groups, a 3% solution of formalin was administered into the crops (5, 10, 15 and 20 ml/bird/day). Total amount of formalin utilized during the experiment in the feed of individual bird of groups given 2.5, 5 and 10 ml/kg was 6.25, 3.9 and 1.6% higher than those administered 5, 10 and 20 ml of 3% formalin into crop, respectively. Body mass and feed intake in all feed-mixed groups and those given 5 and 10 ml formalin (3%) into the crop were not significantly different from control. Administration of 15 and 20 ml formalin (3%) into crop resulted in depression, delayed onset of crowing, significantly decreased feed intake, lower body mass, decreased mass and volume of testes, ulceration in crops, sloughing of mucosa and petechial haemorrhages in proventriculus. All the groups given formalin had significantly smaller diameters of seminiferous tubules. Kidneys of the birds administered formalin into crop exhibited pyknotic nuclei of epithelial cells in proximal tubules. Non-significant differences in different parameters and lesser degree of pathological changes in birds given formalin-mixed feed than their corresponding crop-administered groups suggested that formalin present in the feed had partially evaporated. Therefore, birds ingested less amount of formalin than that originally mixed in the feed.

Administration, Oral↗
PubMed2003

Role of birds in transmission of classical swine fever virus.

Active transmission of classical swine fever virus (CSFV) was studied in six birds (five ravens, one hooded crow) and two laying hens. Cloacal swabs, blood and organs of birds and hens as well as blood and organ samples of pigs which had been fed with faeces derived from CSFV infected birds or which had come in contact with faeces of infected hens were negative for CSFV. None of the animals seroconverted during the study. This result demonstrates that active virus transmission by these animals is unlikely. Dissemination of CSFV from wild boar to domestic pigs is discussed.

Animals↗
PubMed2000

The significance of orbital anatomy and periocular wrinkling when performing laser skin resurfacing.

Knowledge of orbital anatomy and the interaction of muscle contractions, gravitational forces and photoagingis fundamental in understanding the limitations of carbon dioxide (CO2) laser skin resurfacing when rejuvenating the skin of the periocular area. Laser resurfacing does not change the mimetic behavior of the facial muscles nor does it influence gravitational forces. When resurfacing periocular tissue, the creation of scleral show and ectropion are a potential consequence when there is an over zealous attempt at improving the sagging malar fat pad and eyelid laxity by performing an excess amount of laser passes at the lateral portion of the lower eyelid. This results in an inadvertent widening of the palpebral fissure due to the lateral pull of the Orbicularis oculi. Retrospectively, 85 patients were studied, who had undergone periorbital resurfacing with a CO2 laser using anew treatment approach. The Sharplan 40C CO2 Feather Touchlaser was programmed with a circular scanning pattern and used just for the shoulders of the wrinkles. A final laser pass was performed with the same program over the entire lower eyelid skin surface, excluding the outer lateral portion (e.g. a truncated triangle-like area),corresponding to the lateral canthus. Only a single laser pass was delivered to the lateral canthal triangle to avoid widening the lateral opening of the eyelid, which might lead to the potential complications of scleral show and ectropion. When the area of the crows' feet is to be treated, three passes on the skin of this entire lateral orbital surface are completed by moving laterally and upward toward the hairline. Patients examined on days 1, 7, 15, 30, 60, and one year after laser resurfacing showed good results. At two months after treatment, the clinical improvement was rated by the patient and physician as being "very good" in 81 of the 85 patients reviewed. These patients underwent laser resurfacing without complications. The proposed technique of periocular resurfacing prevents complications of scleral show and laxity in the lateral eyelid opening and even ectropion, because treatment conforms to the osseo-muscular anatomical relationship of eyelid structures.

Aging↗
PubMed2001

Botulinum-A toxin treatment of the lower eyelid improves infraorbital rhytides and widens the eye.

Botulinum-A exotoxin (BTX-A) can be used cosmetically to improve rhytides, particularly of the upper one-third of the face. In this study, fifteen women had BTX-A (BOTOX, Allergan, Inc.) injected into the orbicularis oculi muscle. One lower eyelid received two units just subdermally in the midpupillary line three millimeters below the ciliary margin. The opposite periocular area received two units BTX-A in the lower eyelid with 12 units BTX-A injected into the lateral orbital ("crow's foot") area. Three injections of four units each were placed 1.5 cm from the lateral canthus, each 1 cm apart. Patients and physicians independently evaluated the degree of improvement (grade 0 = no improvement, grade 1 = mild improvement, grade 2 = moderate improvement, and grade 3 = dramatic improvement). An independent photographic analysis was performed. Patients reported a grade of 0.73 when two units were injected alone into the lower lid, and a grade of 1.9 when the lower eyelid and the lateral orbital areas were injected. Physician assessment was grade 0.7 with injection of the eyelid alone and grade 1.8 with injection of the lower eyelid and lateral orbital area. Single investigator photographic analysis demonstrated that 40% of the subjects who had injection of the lower eyelid alone had an increased palpebral aperture (IPA), while 86% of the subjects who had injection of the lower eyelid and lateral orbital area had an IPA. Subjects receiving two units alone had an average 0.5 mm IPA and a mean 1.3 mm IPA at full smile. Concomitant treatment of the lateral orbital area produced a mean 1.8 mm IPA at rest and a mean 2.9 mm IPA at full smile. The results were more notable in the Asian eye. Two units of BTX-A injected into the lower eyelid orbicularis oculi muscle improves infraorbital wrinkles, particularly when used in combination with BTX-A treatment of the lateral orbital area.

Adolescent↗
PubMed2002

Decreased tear expression with an abnormal Schirmer's test following botulinum toxin type A for the treatment of lateral canthal rhytides.

BACKGROUND: Inactivation of muscles of facial expression by chemodenervation with botulinum toxin remains an off-label indication. Nevertheless, it continues to be a safe and effective technique to improve dynamic rhytides and is the treatment of choice for the hypertrophic lateral fibers of the orbicularis oculi muscle that can cause the superimposed crow's feet. OBJECTIVE: Although infrequent and self-limiting, the complication of unexpected muscle weakness from toxin diffusion or erroneous placement is documented. METHODS: However, injection into the pretarsal portion of the orbicularis oculi muscle resulting in unilateral ocular irritation and diminished tear expression as evidenced by a dry eye and an abnormal Schirmer's test has rarely been reported. Direct injection into the pretarsal fibers of the muscle as opposed to diffusion of the toxin into the muscle fibers or the lacrimal gland was consistent with the onset of action of the toxin and the prolonged duration of the ocular symptoms. RESULTS: Treatment consisted of ocular lubrication until the effects of the toxin dissipated and muscle tone returned. Subsequent treatment did not result in a result in a recurrence of adverse sequelae. CONCLUSIONS: Facial muscles are small, not isolated, and often have fibers that interdigitate. An important factor in the administration of botulinum toxin is the identification of the muscles responsible for the corresponding rhytide. Precise knowledge of muscular anatomy and function will aid in minimizing this and other potential complications.

Botulinum Toxins, Type A↗
PubMed2003

Botulinum toxin A treatment of perioral rhytides.

BACKGROUND: Botulinum toxin A is well documented as a useful therapy for smoothing dynamic facial rhytides of the upper face. Most controlled studies have focused on the treatment of glabellar frown lines, horizontal forehead lines, and crow's feet. Reports of botulinum toxin A use in the lower face are few and anecdotal. OBJECTIVE: We present our experience using botulinum toxin A in the lip as a treatment of vertical perioral rhytides, which resulted in the added cosmetic benefits of lip eversion and enhanced lip fullness. METHODS: Eighteen patients were injected with botulinum toxin A into the vertical lip rhytides. The effect of treatment was evaluated at 2 to 3 weeks after procedure. RESULTS: Smoothening of hyperfunctional lines and upper lip fullness/eversion is observed in patients treated with perioral botulinum toxin A injections; 72% of patients continued treatment. CONCLUSIONS: In select patients, perioral botulinum toxin A results in amelioration of perioral rhytides and enhancement of lip fullness and lip eversion.

Adult↗
PubMed2003

Subtrochanteric shortening and derotational osteotomy in primary total hip arthroplasty for patients with severe hip dysplasia: 5-year follow-up.

Twenty-one primary hip arthroplasties were performed in Crowe grade 3 or 4 hip dysplasia using a subtrochanteric shortening osteotomy. Average patient age was 48.2 years. Average follow-up was 5.8 years (minimum, 2 years). Femoral fixation was cemented in 10 hips and uncemented in 11 hips. All acetabular components were uncemented, with 33% requiring structural autograft. Ninety-one percent of femoral osteotomies healed without complication. Two osteotomy nonunions required revision. Two acetabular revisions were performed for malposition and polyethylene failure. Three patients experienced postoperative dislocation. One cemented femoral component was revised for loosening. However, no neurologic deficiencies were identified. Harris hip score improved from 32.5 to 73.6. Limp improved in 60% of patients and dependence on assistive walking device improved in 40% of patients. Subtrochanteric shortening osteotomy is a safe and predictable method of restoring the anatomic hip center in high developmental hip dislocation. However, the complication rate in these patients is higher than primary hip arthroplasty for osteoarthritis.

Adult↗
PubMedDate not supplied

[Bilateral hip joint replacement as a one-stage or two-stage procedure for dysplastic coxarthritis: a comparative analysis of 30 patients].

AIM: Dysplastic coxarthritis usually occurs earlier than primary coxarthritis. As a rule dysplastic coxarthritis mostly affects young and active individuals. Bilateral coxarthritis may lead to severe impairment requiring surgical replacement of both hip joints, as the patients are frequently dissatisfied with the substitution of one joint alone. METHOD: In a retrospective study, 15 patients with bilateral hip dysplasia who had received total endoprostheses in both hip joints in a one-stage procedure (group A) were compared to 15 patients with bilateral dysplasia who had been operated on bilaterally in two stages (group B). Group B was subdivided into B1 (first side) and B2 (second side). All dysplasias were classified according to Hartofilakidis and Crowe. RESULTS: On the first postoperative day, group A experienced a mean drop of 33.9% in haemoglobin values, group B1 a mean drop of 25.1% and group B2 a mean drop of 26.3%. Patients of groups A/B1/B2 received on average 1.7/1.1/1.3 units of autologous blood and 1.2/0.1/0.3 units of foreign blood, respectively. Both groups experienced an improvement in their quality of life due to marked improvements in their Harris Hip Score and UCLA Score. Group A had no higher rate of complications. CONCLUSION: Although the single-stage procedure involved greater effort in terms of physiotherapy, patients preferred bilateral implantation of total hip endoprosthesis in a single surgical session because they needed to undergo the process of operation, mobilisation and rehabilitation only once.

Adult↗
PubMed1978

Stepwise mutation model and distribution of allelic frequencies in a finite population.

A mathematical theory is developed that enables us to derive a formula for the equilibrium distribution of allelic frequencies in a finite population when selectively neutral alleles are produced in stepwise fashion (stepwise mutation model). It is shown that the stepwise mutation model has a remarkable property that distinguishes it from the conventional infinite allele model (Kimura-Crow model): as the population size increases indefinitely while the product of the effective population size and the mutation rate is kept at a fixed value, the mean number of different alleles contained in the population rapidly reaches a plateau which is not much larger than the effective number of alleles (reciprocal of homozygosity).

Alleles↗
PubMed1981

Functional cooperation of the dnaE and dnaN gene products in Escherichia coli.

A system was designed to isolate second-site intergenic suppressors of a thermosensitive mutation of the dnaE gene of Escherichia coli. The dnaE gene codes for the alpha subunit of DNA polymerase III [McHenry, C. S. & Crow, W. (1979) J. Biol. Chem. 254, 1748-1753]. One such suppressor, named sueA77, was finely mapped and found to be located at 82 min on the E. coli chromosome, between dnaA and recF, and within the dnaN gene [Sakakibara, Y. & Mizukami, T. (1980) Mol. Gen. Genet. 178, 541-553]. The dnaN gene codes for the beta subunit of DNA polymerase III holoenzyme [Burgers, P. M. J., Kornberg, A. & Sakakibara, Y. (1981) Proc. Natl. Acad. Sci. USA 78, 5391-5395]. The sueA77 mutation was trans-dominant over its wild-type allele, and it suppressed different thermosensitive mutations of dnaE with different maximal permissive temperature. These properties were interpreted as providing genetic evidence for interaction of the dnaE and dnaN gene products in E. coli.

Bacteriophage lambda↗
PubMed1987

Molecular clock rates at loci under stabilizing selection.

Under stabilizing selection in a finite population, lambda, the rate of allelic substitutions at a locus is approximately lambda approximately mu(1 + S)-1/2, where mu is the mutation rate. S, the stringency of selection upon new mutants, is defined by S = NVm/Vs, where N is the population size and Vm/Vs is a measure of the average fitness decrease experienced by new mutants. The approximation holds both for a "lonely" locus, which is the sole provider of genetic variation for the character under selection, and for an "embedded" locus, which is not. In both cases I use the Crow and Kimura model of a continuum of alleles with Gaussian selection and mutation. Monte Carlo simulations corroborate the substitution rate formula. Some molecular evolution data suggest the potential utility and limitations of the formula for estimating population size, mutation, and selection parameters. This work agrees with the rest of nearly neutral theory in emphasizing the important role of population size for substitution rates.

Alleles↗
PubMed1997

Changes in multiple brain regions underlie species differences in a complex, congenital behavior.

The evolutionary brain modifications that produce any complex, congenital behavioral difference between two species have never been identified. Evolutionary processes may (i) alter a single, "higher" brain area that generates and/or coordinates the diverse motor components of a complex act; (ii) separately change independent, "lower" brain areas that modulate the fine motor control of the individual components; or (iii) modify both types of areas. This study explores the brain localization of a species difference in one such behavior, the crowing of chickens (Gallus gallus domesticus) and Japanese quail (Coturnix coturnix japonica). Two major subcomponents of the behavioral difference can be independently transferred with interspecies transplantation of separate brain regions, despite the fact that these components, sound and patterned head movement, occur together in a highly integrated fashion. To our knowledge, this is the first experimental demonstration that species differences in a complex behavior are built up from separate changes to distinct cell groups in different parts of the brain and that these cell groups have independent effects on individual behavioral components.

Animals↗
PubMed1999

Prehistoric birds from New Ireland, Papua New Guinea: extinctions on a large Melanesian island.

At least 50 species of birds are represented in 241 bird bones from five late Pleistocene and Holocene archaeological sites on New Ireland (Bismarck Archipelago, Papua New Guinea). The bones include only two of seabirds and none of migrant shorebirds or introduced species. Of the 50 species, at least 12 (petrel, hawk, megapode, quail, four rails, cockatoo, two owls, and crow) are not part of the current avifauna and have not been recorded previously from New Ireland. Larger samples of bones undoubtedly would indicate more extirpated species and refine the chronology of extinction. Humans have lived on New Ireland for ca. 35,000 years, whereas most of the identified bones are 15,000 to 6,000 years old. It is suspected that most or all of New Ireland's avian extinction was anthropogenic, but this suspicion remains undetermined. Our data show that significant prehistoric losses of birds, which are well documented on Pacific islands more remote than New Ireland, occurred also on large, high, mostly forested islands close to New Guinea.

Animals↗
PubMed2002

Oxidation and nitrosation in the nitrogen monoxide/superoxide system.

Based on the previous report of McCord and co-workers (Crow, J. P., Beckman, J. S., and McCord, J. M. (1995) Biochemistry 34, 3544-3552), the zinc dithiolate active site of alcohol dehydrogenase (ADH) has been studied as a target for cellular oxidants. In the nitrogen monoxide ((*NO)/superoxide (O(2)) system, an equimolar generation of both radicals under peroxynitrite (PN) formation led to rapid inactivation of ADH activity, whereas hydrogen peroxide and ( small middle dot)NO alone reacted too slowly to be of physiological significance. 3-Morpholino sydnonimine inactivated the enzyme with an IC(50) value of 250 nm; the corresponding values for PN, hydrogen peroxide, and (*NO) were 500 nm, 50 microm, and 200 microm. When superoxide was generated at low fluxes by xanthine oxidase, it was quite effective in ADH inactivation (IC(50) (XO) approximately 1 milliunit/ml). All inactivations were accompanied by zinc release and disulfide formation, although no strict correlation was observed. From the two zinc thiolate centers, only the zinc Cys(2)His center released the metal by oxidants. The zinc Cys(4) center was also oxidized, but no second zinc atom could be found with 4-(2-pyridylazo)resorcinol (PAR) as a chelating agent except under denaturing conditions. Surprisingly, the oxidative actions of PN were abolished by a 2-3-fold excess of (*)NO under generation of a nitrosating species, probably dinitrogen trioxide. We conclude that in cellular systems, low fluxes of (*)NO and O(2) generate peroxynitrite at levels effective for zinc thiolate oxidations, facilitated by the nucleophilic nature of the complexed thiolate group. With an excess of (*)NO, the PN actions are blocked, which may explain the antioxidant properties of (*)NO and the mechanism of cellular S-nitrosations.

Animals↗