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Biomedical subjects

M E Cohen

Publications and source records attributed to M E Cohen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Characteristics of the Functional Independence Measure in traumatic spinal cord injury.

OBJECTIVES: The characteristics of the Functional Independence Measure (FIM) were examined for spinal cord injury (SCI) in regard to norms over time by level and completeness of injury, differential benefit of motor and cognition subscales, and "ceiling effect" after rehabilitation discharge. DESIGN: Descriptive study of raw FIM data collected prospectively at admission and discharge from acute inpatient rehabilitation, and at 1, 2, and 5 years after injury. SETTING: National Database of the 18 Spinal Cord Injury Model Systems. SUBJECTS: Persons with SCI, age 16 and over, with functionally complete injuries at inpatient rehabilitation admission (ASIA grades A, B, or C), admitted to Model System an average of 8 days after injury (standard deviation = 13, median = 1 day). Maximum sample sizes for which data were available were: at rehabilitation admission, 3,971 cases; at discharge, 4,033; at year 1 postinjury, 903; 2 years, 712; and 5 years, 570. OUTCOME MEASURES: The FIM motor and cognition subscales. RESULTS: There is a substantial ceiling effect of the FIM cognition items even by inpatient rehabilitation discharge, ie, 80% to 90% of the cases average 6 to 7 (independent or modified independence) across the 5 FIM cognition items. At 1 year 89% to 97% of cases were rated independent. FIM motor items were consistent with level of injury and neurologic status. Motor items (excluding locomotion items) were highly intercorrelated (correlations range from .58 to .92 for self care, sphincter control, and mobility items). Trends over years 1, 2, and 5 were stable for both motor and cognition subscales. FIM motor gains were greatest between admission and discharge and gains continued through 1 year after injury, but at a much-decreased rate. CONCLUSIONS: The cognition items are not informative for detecting changes over time in SCI; at best, these items could serve as a crude cognition screening assessment. Motor items, in contrast, appear to reflect well the functional status of individuals. High correlations among several of the motor items suggest item redundancy. FIM motor scores illustrated the improvements in neurologic and ASIA scores in appropriate cases. Individuals with ASIA impairment grades of B or C at admission make the most gains in FIM motor scores.

Activities of Daily Living↗
PubMed1999

Palatal tubercles, palatal tori, and mandibular tori: prevalence and anatomical features in a U.S. population.

The prevalence and features of 3 types of exostoses commonly encountered during periodontal surgery were studied in a sample of 328 modern American skulls drawn from the collection at the American Museum of Natural History. Measurements were made of the height, width, and breadth of exostoses. The relationship to teeth or other skeletal structures was also recorded. Palatal tubercles were observed in 56% of all skulls (69% of all dentate skulls), with higher prevalences among males and African-Americans. Palatal tubercles were commonly associated with second and third molars, and were usually directly lateral to and a mean of 11.4 mm from the greater palatine foramen. Mandibular tori were observed in 27% of all skulls (42% of dentate skulls), with higher prevalences seen among African-Americans and males. The importance of these findings relates to the frequent need for exostosis removal to permit proper flap adaptation, especially in the posterior maxilla, and to the potential use of the mandibular and palatal tori as sources of autogenous cortical bone.

Adolescent↗
PubMed1998

Human SLUG gene organization, expression, and chromosome map location on 8q.

SLUG is a member of the snail family of zinc finger proteins. It is involved in epithelial to mesenchyme cell transition during neurulation and plays a role in limb bud development. We have isolated and described the human SLUG gene by sequencing a region spanning 4034 bp. The human SLUG gene contains three exons. The SLUG transcript is 2.2 kb and is found in placenta and adult heart, pancreas, liver, kidney, and skeletal muscle, and it codes for a protein of 268 amino acids and 29.989 kDa. This protein contains five zinc finger regions. The human SLUG protein is 95, 93, and 88% homologous to mouse, chicken, and Xenopus slug, respectively, but shows only 47% homology to mouse Snail. The zinc finger region is 100% identical between human and mouse Slug. Slug maps to the long arm of chromosome 8, closely linked to D8S2090 between D8S519 and D8S1098.

Amino Acid Sequence↗
PubMed1998

Second malignancies in young children with primary brain tumors following treatment with prolonged postoperative chemotherapy and delayed irradiation: a Pediatric Oncology Group study.

Between 1986 and 1990, the Pediatric Oncology Group conducted a study in which 198 children younger than 3 years of age with malignant brain tumors were treated with prolonged postoperative chemotherapy in an effort to delay irradiation and reduce long-term neurotoxicity. Children younger than 2 years of age received 24 months of chemotherapy followed by irradiation, and those between 2 and 3 years of age received 12 months of chemotherapy plus irradiation. Chemotherapy was given in 28-day cycles (AAB, AAB), with cycle A = vincristine (0.065 mg/kg) intravenously on days 1 and 8 and cyclophosphamide (65 mg/kg) intravenously on day 1, and cycle B = cisplatinum (4 mg/kg) intravenously on day 1 and etoposide (6.5 mg/kg) intravenously on days 3 and 4. Five of the 198 children developed second malignancies, with a cumulative risk at 8 years of 11.3% (95% confidence interval [CI], 0-39%). Four of the five second malignancies occurred in children younger than 2 years of age at diagnosis, with a cumulative risk at 8 years of 18.9% (CI, 0-70%). Initial diagnoses were choroid plexus carcinoma (2 children), ependymoma (1 child), desmoplastic infantile ganglioglioma (2 children), and medulloblastoma (1 child). Duration from diagnosis of initial tumor to second malignancy was 33, 35, 57, 66, and 92 months. Three children younger than 2 years of age developed lymphoproliferative disease, that is, myelodysplastic syndrome (2 children), both with monosomy 7 deletions, and acute myelogenous leukemia (1 child), after 24 to 26 cycles of chemotherapy, including 8 cycles of etoposide. Two of 3 received craniospinal irradiation (2,560/3,840 cGy) and (3,520/5,320 cGy). Time to second malignancy was 7 years 8 months, 4 years 9 months, and 2 years 9 months. Two children developed solid tumors, at 5 years 6 months and 2 years 11 months, respectively, after initiation of treatment. A sarcoma developed after 26 cycles of chemotherapy and no irradiation, and a meningioma developed after 12 cycles of chemotherapy and local craniospinal irradiation. Potential causative factors for this high rate of secondary malignancies include prolonged use of alkylating agents and etoposide with or without irradiation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

A test of the 1992 International Standards for Neurological and Functional Classification of Spinal Cord Injury.

This study was designed to test the 1992 International Standards for Neurological and Functional Classification of Spinal Cord Injury. One hundred and six professionals in the field of spinal cord injury attending an instructional course at the 1994 ASIA Meeting participated in the test. Participants completed a pretest and posttest in which they classified two patients who had a spinal cord injury (one with complete tetraplegia and one with incomplete paraplegia) by sensory and motor levels, zone of partial preservation (ZPP), ASIA Impairment Scale and completeness of injury. Between tests, three members of the ASIA Standards Executive Committee gave presentations on the neurological assessment, scoring, scaling and classification of spinal cord injury and a video of the actual examinations of the two cases was viewed. Percent 'correct' (as defined by the ASIA Standards Committee) was calculated for sensory and motor levels, ZPP, ASIA Impairment and completeness. Overall, the analyses showed that participants had very little difficulty in correctly classifying the patient with complete tetraplegia. Pretests scores ranged from 72% (left motor level) to 96% (complete injury), posttest scores from 73% (left motor level) to 100% correct (complete injury). For the patient with incomplete paraplegia (Case 2), scores were considerably lower. Pretest scores ranged from 16% (right motor level) to 95% correct (incomplete injury); posttest scores from 21% (right motor level) to 97% correct (incomplete injury). The results showed that further revisions of the 1992 Standards and more training is needed to ensure accurate classification of spinal cord injury.

Chi-Square Distribution↗
PubMed1998

A quantile plot for simultaneous representation of clinical and statistical attributes of probing change: application to early identification of the downhill patient.

When multiple periodontal sites are observed in patients over time there is an intention to identify those sites where there is important change, typically loss of attachment or increase in probing depth. A change may be declared if it: (a) exceeds a threshold level, and/or (b) is determined to be statistically significant (e.g. regression slope different from zero), perhaps after (c) that significance level has been corrected for multiple testing. These criteria are not often considered when clinical or research decisions are made and there is no universal protocol for their evaluation. A quantile (uniform probability) plot, modified to incorporate additional information, is proposed as a graphical method for the display of changes at multiple sites within a mouth. This plot identifies, for each site, clinical changes beyond a threshold, site-wise statistical significance and statistical significance adjusted for multiple testing. These alternative criteria for attachment change are, thereby, made explicit, providing a detailed evaluative context. In addition, this methodology permits incorporation of an estimation procedure for the number of sites for which the null hypothesis of no change is false. This statistic can provide evidence of progressive disease even when no site has significant clinical or statistical change and even if the average change is zero. Use of the quantile plot was elucidated by application to simulated data, and to a clinical dataset using a BASIC program to automate the computational process. In the clinical example presented, the approach appeared more effective in detecting periodontal change than traditional clinical and statistical criteria. Pending technical refinement, this graphical approach may represent a new tool for the early identification of the downhill patient.

Adult↗
PubMed1998

Quantitative contribution of NHE2 and NHE3 to rabbit ileal brush-border Na+/H+ exchange.

Intestinal neutral NaCl absorption, which is made up of brush-border (BB) Na+/H+ exchange linked to BB Cl-/HCO3- exchange, is up- and downregulated as part of digestion and diarrheal diseases. Glucocorticoids stimulate ileal NaCl absorption and BB Na+/H+ exchange. Intestinal BB contains two Na+/H+ exchanger isoforms, NHE2 and NHE3, but their relative roles in rabbit ileal BB Na+/H+ exchange has not been determined. A technique to separate the contribution of NHE2 and NHE3 to ileal BB Na+/H+ exchange activity was standardized by using an amiloride-related compound, HOE-694. Under basal conditions, both NHE2 and NHE3 contribute approximately 50% to ileal Na+/H+ exchange. Glucocorticoids (methylprednisolone) increase BB Na+/H+ exchange (2.5 times) but increase only ileal NHE3 activity (4.1 times), without an effect on NHE2 activity. Thus ileal BB Na+/H+ exchange in animals treated with glucocorticoids is 69% via NHE3. A quantitative Western analysis for NHE3 was developed, using as an internal standard a fusion protein of the COOH-terminal 85 amino acids of NHE3 and maltose binding protein. Glucocorticoid treatment increased the amount of BB NHE3. The quantitative Western analysis showed that NHE3 makes up 0.018% of ileal BB protein in control rabbits and 0.042% (2.3 times as much) in methylprednisolone-treated rabbits. Methylprednisolone treatment did not alter the amount of ileal BB NHE2 protein. NHE3 turnover number was estimated to be 458 cycles/s under basal conditions and 708 cycles/s in glucocorticoid-treated ileum. Thus methylprednisolone stimulates ileal BB Na+/H+ exchange activity only by an effect on NHE3 and not on NHE2; it does so primarily by increasing the amount of BB NHE3, although it also increases the NHE3 turnover number.

Animals↗
PubMed1998

Prognostic factors in infants and very young children with intracranial ependymomas.

The Pediatric Oncology Group (1986-1990) conducted a study in which 48 children <3 years of age with intracranial ependymomas were treated with prolonged postoperative chemotherapy (CT) and delayed RT. Thirty-one children, 0-23 months of age at diagnosis (Gp A) received 2 years of CT followed by RT; while 17 children, 24-36 months of age at diagnosis (Gp B) received CT for 1 year followed by radiation. One-year survivals were 87% (Gp A) and 94% (Gp B) and 2-year survivals were 67% (Gp A) and 82% (Gp B). In subsequent years a significant divergence in survivals according to age has been noted (p = 0.04). Five-year survivals were 25.7% (Gp A) vs. 63.3% (Gp B). The curves began to diverge 1 year following diagnosis. Other than age, the only significant prognostic factor was degree of surgical resection: 5-year survivals were 66% (total resection) vs. 25% (subtotal resection). Neither the presence of metastases, degree of anaplasia nor the degree of surgical resection varied significantly according to age at diagnosis. The most likely reason for the difference in survivals between the two age groups relates to the timing of radiation following CT, i.e., 1-year delay in children 24-36 months of age compared to a 2-year delay in children 0-23 months of age. An alternative but less likely hypothesis is that ependymomas in the younger children have a more aggressive biology. In contrast, survivals in the 24- to 36-month group are much better than previous reports in the literature suggesting that prolonged postoperative CT may allow both a delay in CRT as well as provide improved survivals. Based on these results, future treatment trials should emphasize maximal surgical resection and a delay in radiation of no more than 1 year.

Age Distribution↗
PubMed1998

Development of new photopolymerizable dental sealants.

This paper describes the results obtained in the optimization of the composition of dental sealants in relation to the nature and proportions of monomer mixtures and photoinitiating system employed. The quantification and variation of certain parameters which determine the quality of a dental sealant (such as viscosity and penetrating power, residual double bonds, solubility and absorption, volume shrinkage and certain specific mechanical properties) have resulted in the development of new formulations. The composition which has achieved the best results of all the above properties was that corresponding to the monomer mixture bis-GMA/tri(ethylene glycol) dimethacrylate (TEGDMA) 40/60 wt%, and the photoinitiating system camphorquinone (CQ) with co-initiators N,N,3,5-tetramethyaniline (TMA) or N,N-dimethyl-p-toluidine (DMPT) in the ratio 1:1. The final properties and characteristics of the obtained formulations are superior to those of commercial dental sealants currently in use.

Absorption↗
PubMed1998

A prospective study of sealant application in navy recruits.

A 3-year prospective study was designed to evaluate sealants in preventing the formation and progression of caries in a young adult military population. United States Navy dentists performed dental examinations on recruits being in-processed at the Naval Training Center, San Diego, California. Contralateral molar pairs (same arch) without caries or restorations were selected. Occlusal decalcification and lesions limited to enamel were also eligible, but teeth with proximal decalcification were disqualified. The sample consisted of 860 molar pairs in 529 Navy recruits, each contributing one or two pairs. Required annual dental examinations provided follow-up data, with results being recorded on postcards that were mailed back to the investigator. Yearly response rates were as follows: 1 year, 62.2% (483 molar pairs); 2 year, 47.8% (378 molar pairs); and 3 year, 41.4% (317 molar pairs). The response rate for pairs having at least one observation during the 3-year follow-up was 72.6% (563 molar pairs), with a caries conversion rate of 1.2% (7 teeth) on sealed teeth and 5.3% (32 teeth) on control teeth, yielding 35 discordant molar pairs on 33 recruits (30 on control teeth and 5 on sealed teeth) (p < 0.0001). These results confirm the efficacy of sealants in significantly reducing the rate caries in a young adult military population.

Adult↗
PubMed1997

The role of the Internet in medical decision making.

The Internet has dramatically changed the means by which information is obtained. Accurate, up-to-date information is vital to maintain the quality of healthcare, especially as US healthcare delivery changes to a primary care-based system. The availability of this new and potentially vast source of information also affects strategies for medical decision making. In this article, use of online information in our medical center is discussed, together with the impact of a locally-developed decision support system. This system first contained components for differential diagnosis as well as computer-assisted instruction. Initially, online searching was limited to Medline literature searches. This component has now been expanded to include important new tools for accessing medical information on the Internet.

Artificial Intelligence↗
PubMed1997

Use of shoulder flexors to achieve isometric elbow extension in C6 tetraplegic patients during weight shift.

The anterior deltoid muscle has been found to be active during elbow extension in normal volunteers and in C6 tetraplegic patients lacking a functional triceps. Using surface electromyography (EMG) on normal volunteers and on patients with spinal cord injury (SCI) at the C6 motor level, we evaluated whether the anterior deltoid and biceps brachii muscles are active during closed chain elbow extension in a simulated weight shift position. Thirteen normal volunteers performed isometric contractions at 5 submaximal levels of force ranging from 4-25 kg. Six SCI patients performed isometric contractions at force levels of 20%, 40%, 60%, 80% and 100% maximum voluntary contraction (MVC). Surface EMG over the right biceps, triceps, and anterior deltoid muscles was recorded for each participant and the root mean square (rms) electromyographic activity level for each muscle was determined at each level of force. Statistical analyses using repeated ANOVA with Tukey HSD post-hoc tests were performed for each level of force. The results indicated increasing rms activity of the triceps and anterior deltoid muscles with increasing force in normal volunteers to a significant degree (P < 0.05). SCI patients showed significant increasing activity of the anterior deltoid with increasing force, but showed minimal triceps rms activity. In both groups, the biceps showed minimal rms activity. SCI patients exhibited significantly greater rms activity of the anterior deltoid at low force compared with normal volunteers. The results suggest that the anterior deltoid aids in isometric elbow extension during a simulated weight shift maneuver.

Activities of Daily Living↗
PubMed1997

On the interpretation of microbial clusters in periodontal disease.

Cluster analysis is sometimes used in periodontal research to describe patterns of microbial identifications observed among cases (subjects or sites). These patterns are assumed to define subsets of cases that are meaningful, in the sense of defining periodontal subgroups that have reliable differences in some aspect of their disease. However, cluster analysis is an exploratory, first-stage technique that does not incorporate the machinery that allows one to evaluate the statistical significance and reliability of the patterns observed. Problems inherent in drawing inferences from cluster analysis are discussed and, as one methodological example of how the statistical significance of clustering might be determined, a randomization-based test for binary scaled microbial identifications is described. The introduction of cluster analysis to the study of periodontal microbiology was important and innovative, but future work needs to incorporate validation by either statistical means or independent replication. The present rarity of such confirmatory methods in the literature suggests caution in accepting specific cluster-based hypotheses about patient-microbial patterns.

Analysis of Variance↗