Biomedical subjects
S Berkowitz
Publications and source records attributed to S Berkowitz.
Commentary on speech outcome and maxillary growth in patients with unilateral complete cleft lip/palate operated on at 6 versus 12 months of age.
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Shape changes in the cleft palate maxilla: a longitudinal study.
OBJECTIVE: The purpose of this study was to compare the shape of the maxilla in Norma lateralis of cleft lip and palate (CLP) patients with non-CLP controls matched for sex and age. This study utilized elliptical Fourier functions to assess the presence of residual shape changes in the cleft palate maxilla after treatment, compared with controls. DESIGN: Longitudinal data (n = 25) were available from the Miami Craniofacial Anomalies Foundation. From these data, two samples were selected: group I (mean age and SD, 5.06 +/- 1.82 years) after lip surgery and the initiation of palate surgery and group II (16.58 +/- 2.42 years) well after the conclusion of surgery. Twenty-two of these patients were matched with controls (5.11 +/- 1.33 and 15.91 +/- 2.25 years, respectively). The maxillary outline as seen on the lateral radiograph was (1) traced, (2) fitted with a series of 48 closely placed points, (3) digitized, and (4) submitted to a specially written routine that computes elliptical Fourier functions (EFFs). These EFFs are close analogs of the bounded maxillary outline as judged by the residual or difference between the observed points and the predicted points generated by the Fourier function. Each maxillary outline was subsequently standardized for size and corrected for positioning in two-dimensional space. RESULTS AND CONCLUSIONS: Utilizing a three-way multivariate analysis of variance, statistically significant shape differences were obtained for both young and older groups, as well as between the CLP and controls. No significant gender differences were found. Morphological differences consisted of a posterior repositioning of the nasal crest aspect in the CLP cases. These results suggest that although a clinically satisfactory treatment result was obtained, differences in maxillary shape remain.
A multicenter retrospective 3D study of serial complete unilateral cleft lip and palate and complete bilateral cleft lip and palate casts to evaluate treatment: part 1--the participating institutions and research aims.
OBJECTIVE: To compare the multicenter retrospective and prospective spatiotemporal (4D) serial analyses of complete unilateral (CUCLP) and complete bilateral (CBCLP) cleft lip and palate casts that had undergone different treatment procedures. The involved institutions are Miami Craniofacial Anomalies Foundation, South Florida Cleft Palate Clinic; University Hospital of Nijmegen Cleft Palate Center; Free University of Amsterdam Cleft Palate Center; Academic Hospital (Dijkzigt/Sophia) Rotterdam Cleft Palate Center; Center for Craniofacial Anomalies, University of Illinois College of Medicine; Cleft Palate Center, Sahlgrenska University Hospital, Göteborg, Sweden; and Children's Memorial Medical Center, Northwestern University Cleft Palate Institute. DESIGN: Using serial casts of the upper jaw and an electromechanical digitizer with special Cad-Cam software (CadKey), the occlusal relationships and morphometric palatal growth changes that occur under the influence of presurgical orthopedics and various surgical procedures will be studied. It is anticipated that 3D geometric data extracted from serial casts will identify the important geometric palatal parameters present before cleft surgical closure, which will supply objective criteria for establishing a scientific basis for improved surgical therapy. This research study will test three hypotheses: (1) Conservative (varying the timing of surgical cleft closure according to the size of the cleft space) lip and palatal surgery will permit "catch-up" palatal growth and normalize palatal growth and development. (2) The amount of mucoperiosteal tissue relative to the size of the cleft space is important in determining the timing of palatal surgery, as it influences the degree of scarring and ultimately the palate's adult size and form. (3) Presurgical orthopedics (the use of appliances soon after birth) can stimulate palatal growth beyond its normal growth potential. RESULTS: In a previous project and again after reviewing the data already collected during the first year of this study, it has been shown that incremental changes in size of palatal segments in CUCLP and CBCLP cases prior to surgery vary slightly. The CBCLP cases grow slightly faster than CUCLP cases before surgery, but growth of the CBCLP cases decreases in acceleration after surgery. Reasons for these differences will be determined when more cases are analyzed and subjected to biostatistical analysis.
Long-term outcome analysis of two treatment methods for cleft palate: combined levator retropositioning and pharyngeal flap versus double-opposing Z-plasty.
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Prerandomization of clinical trials: a more ethical way for performing cleft palate research.
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Re: Bronshtein M, Blumenfeld I, Blumenfeld Z. Early prenatal diagnosis of cleft lip and its potential impact on the number of babies with cleft lip. Br J Oral Maxillofac Surg 1996; 34: 486-487.
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In search of the harmonious face: Apollo revisited, with an examination of the indications for retrograde maxillary displacement.
A historical review of our perception of facial flatness and convexity and what constitutes "a pleasing face," both in North America and internationally, is provided. Attractive faces may range from slightly flat ("Apollonian") to mildly bimaxillary protrusive, but marked deviations in either direction, from the dish face to extreme bimaxillary protrusion, constitute a deformation and warrant combined orthodontic and surgical treatment. Technical aspects of segmental and total maxillary setback are presented, along with four representative cases.
A new direction for cleft palate research.
Successful outcomes in the treatment of complete unilateral cleft-lip and palate (CUCL/P) and complete bilateral cleft lip and palate (CBCLP) are not obtained universally, despite significant improvements in surgical techniques over the past three decades. In particular, deficient palatal growth may occur even when expert surgical treatment is rendered. The factors which contribute most significantly to unfavorable growth outcomes remain obscure.
The use of gingivoperiosteoplasty in CUCLP.
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A comparison of treatment results in complete bilateral cleft lip and palate using a conservative approach versus Millard-Latham PSOT procedure.
Conservative non-presurgical orthopedic treatment in complete bilateral cleft lip and palate (CBCLP) cases were compared with those treated will the Millard-Latham (M-L) method, which involves the presurgical mechanical retraction of the protruding premaxilla using pinned palatal appliances. In conservatively treated cases, a head bonnet with an external elastic is sometimes used before surgical lip closure to ventroflex the premaxilla thereby reducing tension at the surgical sites. The M-L method involves premaxillary bodily retraction followed by a gingivo-periosteoplasty. In both series of cases the palatal cleft (hard and soft) is closed for patients aged 18 to 30 months using a modified von Langenbeck procedure. A secondary alveolar bone graft is only performed in the conservatively treated series for patients aged 7 to 9 years. Although the premaxilla in 2 of 29 conservatively treated cases were retruded and in anterior crossbite by 10 to 12 years of age, all M-L cases were retruded by 9 years of age requiring maxillary protraction. In the M-L cases 90% showed bony bridging of the alveolar cleft with frequent loss of the lateral incisor space; surgical closure of the nasal floor is facilitated, and early aesthetic improvement is followed by midfacial retrusion.
A dissent: cleft palate closure in the neonate.
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Ethical issues in the case of surgical repair of cleft palate.
There are some advantages to prospective randomized clinical trials (PRCT) to resolve some limited clinical problems. But, when this method is used to determine the best surgical procedure to close the palatal cleft space, there are strong ethical considerations that cannot be overcome. There are two basic problems. The first is having the surgeon perform surgical procedures which he/she does not believe is the treatment of choice or that can be performed as skillfully as others, even after demonstrations. Secondly, this method does not consider the theoretical aspect that many clefts within the same cleft type are different in the relative size of cleft space to size of soft tissue available for closing the cleft space, thereby creating different degrees of scarring. Different outcomes to the same surgery must, therefore, result irrespective of the surgeons' skills or treatment plans. Retrospective research studies, whether they involve one or more institutions, have been and are still very valuable in improving the knowledge base of all areas of cleft palate habilitation.
The monobloc frontofacial advancement: do the pluses outweigh the minuses?
The results of 32 patients who underwent transcranial monobloc frontofacial advancement by the senior author (Wolfe) are examined. Fifteen of the patients were Crouzon's and 17 were Apert's, 14 of whom also underwent simultaneous facial bipartition. The ages ranged from 7 months to 14 years. Although a transcranial facial advancement carries with it substantial risks, with careful consideration of airway control, the anterior cranial base dura, and the retrofrontal dead space, the procedure is recommended for carefully selected patients. The indications and contraindications for the procedure in various age groups are given.
Ultraviolet-visible transient spectroscopy of bacteriorhodopsin mutants. Evidence for two forms of tyrosine-185----phenylalanine.
The photocycle kinetics of the bacteriorhodopsin mutant Tyr-185----Phe has been investigated by UV-visible transient spectroscopy. Flash-induced spectral changes were measured from 100 ns to 500 ms using a gated optical multichannel analyzer on protein samples that were reconstituted in vesicles with Halobacterium halobium lipids. Tyr-185----Phe exhibits a pH-dependent absorbance spectrum reflecting contributions from two different species. At pH 6, the dominant photocycling species has a lambda max near 610 nm although the absorption maximum of light-adapted Tyr-185----Phe is at 581 nm. This red-shifted species does not form any M-like intermediate and undergoes a photocycle similar to that observed for deionized blue membrane. At pH 8, the dominant photoactive form exhibits a lambda max near 550 nm. This purple species, which is blue shifted 20 nm relative to wild-type bacteriorhodopsin, exhibits a photocycle similar to the wild type. However, M formation occurs in 8 microseconds, approximately three times faster than wild-type bacteriorhodopsin at pH 8. In addition, an unusually long lived intermediate absorbing at 610 nm is observed at high pH. In the UV region, a broad band near 300-310 nm is absent in the mutant relative to wild type, consistent with earlier measurements made at low temperature which suggest that Tyr-185 undergoes a change in protonation. Steady-state proton pumping action spectra indicate that the 550 nm species does transport protons but that the blue species is inactive. These results are discussed in terms of a model that hypothesizes that Tyr-185 is located close to the bacteriorhodopsin chromophore and stabilizes the interaction of helices F and G through formation of a polarizable bond with Asp-212.
A comparison of two methods of prompting in training discrimination of communication book pictures by autistic students.
Two methods of prompting were compared for their relative effectiveness in teaching a group of autistic students to discriminate line drawings used in picture communication books. All four students required fewer trials to meet the task criterion using a delayed-prompting technique. Further, students made significantly more errors in the fading-of-prompts design than in the delayed-prompting design. The high rate of errors in faded-prompt sessions resulted in some students displaying aberrant behaviors. The results are discussed in terms of effectiveness of the two teaching methodologies, as well as the consequences of error patterns. Suggestions are made for further research.
Effect of inspired air temperature on genioglossus activity during nose breathing in awake humans.
Experimental data suggest the presence of sensory receptors specific to the nasopharynx that may reflexly influence respiratory activity. To investigate the effects of inspired air temperature on upper airway dilator muscle activity during nose breathing, we compared phasic genioglossus electromyograms (EMGgg) in eight normal awake adults breathing cold dry or warm humidified air through the nose. EMGgg was measured with peroral bipolar electrodes during successive trials of cold air (less than or equal to 15 degrees C) and warm air (greater than or equal to 34 degrees C) nasal breathing and quantified for each condition as percent activity at baseline (room temperature). In four of the subjects, the protocol was repeated after topical nasal anesthesia. For all eight subjects, mean EMGgg was greater during cold air breathing than during baseline (P less than 0.005) or warm air breathing (P less than 0.01); mean EMGgg during warm air breathing was not significantly changed from baseline. Nasal anesthesia significantly decreased the mean EMGgg response to cold air breathing. Nasal airway inspiratory resistance, measured by posterior rhinomanometry in six subjects under similar conditions, was no different for cold or warm air nose breathing [cold 1.4 +/- 0.7 vs. warm 1.4 +/- 1.1 (SD) cmH2O.l-1.s at 0.4 l/s flow]. These data suggest the presence of superficially located nasal cold receptors that may reflexly influence upper airway dilating muscle activity independently of pressure changes in awake normal humans.
Substitution of membrane-embedded aspartic acids in bacteriorhodopsin causes specific changes in different steps of the photochemical cycle.
Millisecond photocycle kinetics were measured at room temperature for 13 site-specific bacteriorhodopsin mutants in which single aspartic acid residues were replaced by asparagine, glutamic acid, or alanine. Replacement of aspartic acid residues expected to be within the membrane-embedded region of the protein (Asp-85, -96, -115, or -212) produced large alterations in the photocycle. Substitution of Asp-85 or Asp-212 by Asn altered or blocked formation of the M410 photointermediate. Substitution of these two residues by Glu decreased the amount of M410 formed. Substitutions of Asp-96 slowed the decay rate of the M410 photointermediate, and substitutions of Asp-115 slowed the decay rate of the O640 photointermediate. Corresponding substitutions of aspartic acid residues expected to be in cytoplasmic loop regions of the protein (Asp-36, -38, -102, or -104) resulted in little or no alteration of the photocycle. Our results indicate that the defects in proton pumping which we have previously observed upon substitution of Asp-85, Asp-96, Asp-115, and Asp-212 [Mogi, T., Stern, L. J., Marti, T., Chao, B. H., & Khorana, H. G. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 4148-4152] are closely coupled to alterations in the photocycle. The photocycle alterations observed in these mutants are discussed in relation to the functional roles of specific aspartic acid residues at different stages of the bacteriorhodopsin photocycle and the proton pumping mechanism.