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Biomedical subjects

D F Cruess

Publications and source records attributed to D F Cruess.

At least 55 records · Page 3Linked to original sources
PubMed1987

Barrett's esophagus. A prevalent, occult complication of gastroesophageal reflux disease.

A prospective study of patients with symptoms of gastroesophageal reflux was undertaken to determine the prevalence of Barrett's esophagus and reevaluate the diagnostic approach necessary to detect this complication. Endoscopy with mucosal biopsy was performed in 97 subjects. Twelve (12.4%) were found to have Barrett's esophagus. The sensitivity and specificity of the endoscopic and radiologic examinations for Barrett's esophagus were prospectively evaluated. Endoscopy (92%) was significantly more sensitive than radiology (24%) in detecting Barrett's esophagus (p less than 0.001). The frequency and severity of reflux symptoms among patients determined to have Barrett's esophagus, reflux esophagitis, or normal esophageal biopsies were quantitatively similar in all three groups, except for significantly greater daytime heartburn in those with reflux esophagitis (p less than 0.01). These data indicate that Barrett's esophagus complicates gastroesophageal reflux more often than previously believed.

Barrett Esophagus↗
PubMed1986

The cytotoxic effect of surgical glove powder particles on adult human vascular endothelial cell cultures: implications for clinical uses of tissue culture techniques.

Clinical use of autogenous endothelial cell (EC) seeding of vascular prostheses (VP) would require reliable methods for EC harvest for immediate seeding or primary culture in a hospital or operating room setting. Observation of glove powder particles (GPP) in failed primary adult human saphenous vein EC (AHSVEC) cultures led us to study the effect of surgical GPP on cultured AHSVEC. Addition of GPP to the culture medium of growing ASHVEC cultures reduced the cell counts in a dose-dependent fashion; the mean concentration of GPP required to produce a greater than 50% decrease in cell number was 1.5 +/- 0.8 (SD) X 10(4) GPP/ml (N = 10 experiments), equivalent to a mean dose of 36 micrograms glove powder per milliliter. The effect was seen within 24 hr of addition of GPP and was not due to interference with EC attachment and spreading or to changes in medium osmolality, pH, glucose, electrolyte, Ca2+, or Mg2+ content. Instead, the effect appeared to be due to a filterable toxin added during the final rubber-vulcanizing stage of glove manufacture, since pure cornstarch particles and epichlorhydrin-treated pure cornstarch did not prevent culture growth, whereas 0.2 micron filtrates of medium incubated with GPP taken directly from gloves were lethal. We conclude that filterable cytotoxic substances from GPP may be an avoidable cause of failure in EC seeding of VP, and may affect surgical wound healing as well.

Cell Adhesion↗
PubMed1986

Adult human endothelial cell enzymatic harvesting. Estimates of efficiency and comparison of crude and partially purified bacterial collagenase preparations by replicate microwell culture and fibronectin degradation measured by enzyme-linked immunosorbent assay.

Reliable enzymatic endothelial cell (EC) harvest methods are required for clinical EC seeding of vascular prostheses by methods analogous to those demonstrated in dogs. But crude collagenases used for EC harvest vary in efficacy and cytotoxicity, and purified collagenases reportedly give low EC yields. To compare different harvest methods, we studied growth curves of primary adult human saphenous vein EC (HSVEC) harvests plated in replicate microwell cultures. The EC yield, defined as attachment-capable ECs obtained per square centimeter of vein lumen, was estimated from the lowest number of ECs counted in lag phase before exponential growth began. With the use of morphometric studies of HSVs that were perfusion-fixed at their original dimensions, the baseline in situ density of ECs available for harvest from HSV was estimated at 1.3 X 10(5) EC/cm2. Crude (CBC) and partially purified bacterial collagenase (PBC) solutions at concentrations with equal levels of basement membrane lysis activity (BMLA) were compared by the replicate microwell method in a series of 21 harvests (six CBC, eight PBC, and seven enzyme-free control harvests). All 14 enzymatic harvests produced confluent EC cultures with no significant difference in mean harvest efficiency between CBC (12% of in situ EC number) and PBC (15%). However, PBC caused less degradation of human fibronectin (p less than 0.0001) as measured by an enzyme-linked immunosorbent assay employing a fibronectin-specific monoclonal antibody. These data suggest that chemically defined mixtures of pure enzymes with BMLA equal to the BMLA of crude collagenase might allow reliable EC harvesting without sacrifice in EC yield but with improved preservation of structures at the EC periphery. EC losses during initial vein dissection may have contributed to the low 12% to 15% efficiency we observed.

Adult↗
PubMed1985

Methicillin-resistant Staphylococcus aureus (MRSA): risk and outcome of colonized vs. infected patients.

A retrospective study of 204 patients culture positive for methicillin-resistant Staphylococcus aureus compared infected and colonized patients. Seventy-eight patients were colonized and never developed infection (C), 24 were colonized and subsequently infected (C----I), and 102 patients had 1 or more nosocomial infections with MRSA at time of first culture (I). The most prevalent sites of infection were wound (26.5%) and blood-stream (20.7%), whereas the respiratory tract and surgical wounds were both frequent sites of colonization. Stepwise discriminant analysis found the most important factors in differentiating likelihood of colonization vs. infection were recent prior hospitalization, history of wound debridement, and number of invasive procedures. Ten percent of (C) died and 25.5% of (I) died. MRSA contributed to death in 57.6% of the (I) deaths (p less than .05). These results underscore the importance of differentiating (C) vs. (I) in hospitals where MRSA is endemic so that early specific treatment may be initiated. Risk factors for infection should be discriminated from those for acquisition of the organism.

Cross Infection↗
PubMed1985

Evaluation of radiology resident cognitive performance.

Using radiographs and slides in three formats, we objectively tested the cognitive performance of 16 residents during an 8-month period. One format tested individual residents with radiographs and required only that a list of findings be provided within a week. For the second method, radiographs were projected to a small group of residents and a single diagnosis for each of ten cases was required. The third format required a larger group of competing residents to view projected slides of ten loosely defined but thematically connected cases and develop one diagnosis. Two of the test formats correlated significantly with a Spearmen rank, r = .50 or better (P less than .025) with a ranking based upon total score on the American College of Radiology Inservice Examination. All three test formats had a Spearmen rank r = .50 or better (P less than .05) when compared with pooled ranking performed by the staff radiologists.

Cognition↗
PubMed1985

Normal erect swallowing. Normal function and incidence of variations.

Of 871 candidates presenting for upper gastrointestinal examinations, 16 met the rigorous criteria established for selecting asymptomatic normal volunteers. Frame-by-frame evaluation of their videorecorded pharyngeal swallow confirmed many observations made previously utilizing cine recording at much higher radiation dosages. In addition, new observations were made: the nasopharynx may not occlude until the bolus is entirely within the pharynx; air mixes with the bolus if the swallow is an "open" type; the epiglottis always inverts in normal individuals regardless of the type of swallow ("open," air filled oro-and hypopharynx into which the swallowed bolus is dropped; "closed," airless oropharynx into which the swallowed bolus is pushed by a continuous peristaltic drive of the tongue and palate, thus reconstituting the pharyngeal space); laryngeal descent may aid in stripping the bolus from the pharynx; the vestibule may not completely close during the swallow and the larynx can still be impervious to the bolus; the peristaltic wave does not begin until the bolus has breeched the cricopharyngeus; the cricopharyngeus may be seen frequently in normal individuals, but does not delay the passage of the bolus; asymmetric flow of the bolus around the larynx is common and may not be the result of epiglottic tilt or head positioning.

Adolescent↗
PubMed1985

Ranking: a reproducible semiobjective means of evaluating overall resident performance.

Eleven staff radiologists evaluated resident performance by independent subjective ranking regardless of residency year. A pooled ranking correlated with a ranking obtained from the total raw score of the American College of Radiology (ACR) Inservice Examination (P less than .005). The staff pooled ranking had a Spearman rank correlation, r = .70, with resident overall performance upon the ACR Inservice Examination. The pooled ranking had a Spearman rank correlation, r = .90, with a subsequent pooled ranking obtained six months later (P less than .0001). This method of ranking accurately predicts ACR Inservice Examination performance and appears to evaluate the objectivity of the staff radiologists involved.

Clinical Competence↗
PubMed1985

Self-reported physical health practices and health care utilization: findings from the National Health Interview Survey.

Cross-sectional physical health practice and health care utilization data from the 1977 National Health Interview Survey were analyzed. After adjusting for the effects of age, sex, race, income, education, and marital status, there were significant relationships between hours of sleep and both doctor visits and hospital days; increased physical activity was associated with fewer doctor visits. Prospective intervention studies are needed to determine whether changes in health practices will lead to decreased utilization.

Adult↗
PubMed1985

Health practices in United States Air Force personnel compared to United States adult civilians.

Seven physical health practices have been found to be related to both physical health and mortality in cross-sectional and longitudinal studies. The practices include adequate rest, sufficient exercise, eating breakfast, no snacking, maintaining a reasonable body weight, no smoking, and use of alcohol in moderation. The purpose of this study was to describe physical health practices in the United States Air Force (USAF) and to compare them to those in the US adult population. In 1977 the USAF conducted a Health Survey that included questions concerning the seven physical health practices, and the National Center for Health Statistic's Health Interview Survey included a Health Practices Supplement. The results indicated a lower level of breakfast eating and more snacking in the USAF compared to other U.S. adults, but the difference may have been due to the relatively younger age distribution in the USAF. Air Force members reported sleeping less, and the females and older persons in both populations reported less physical activity. Air Force females reported drinking more than other females, but there appeared to be less heavy drinking in the USAF. Cigarette smoking in the USAF was slightly higher. The validity of self-reported health practice data is of considerable importance in these studies. However, there is no reason to suspect meaningful differences in reporting between the USAF and US populations.

Aerospace Medicine↗
PubMed1984

Videofluoroscopic identification of two types of swallowing.

Two forms of swallowing were observed during videofluoroscopy in 166 asymptomatic patients, consisting of an air-containing ("open") pharynx in 120 (72%) and an occluded ("closed") pharynx in 46 (28%). The epiglottis inverted differently in the two forms of swallowing.

Deglutition↗
PubMed1984

The cricopharyngeal muscle: a videorecording review.

In a review of 618 videorecordings of the pharynx and esophagus, 77 (10.8%) had cricopharyngeal abnormalities. This represents twice the reported frequency. This paper examines the cricopharyngeal abnormalities. The cricopharyngeal muscle was observed consistently malfunctioning in the same manner in 36 (47%) of the patients. It was observed most consistently (20%) as a prominent structure throughout the swallow (15 patients). It also was observed early in the swallow (13 patients), late in the swallow (six), and obstructing the pharyngoesophageal transition (two). It was observed rising and falling with the motion of the larynx during the swallow. Over half the time (53%), however, it was seen at different times during the swallow, altered its appearance from swallow to swallow, and was seen at different levels. The significance of the cricopharyngeal muscle to the patient's health remains to be determined.

Deglutition↗
PubMed1984

Importance of soft-tissue evaluation in hand and wrist trauma: statistical evaluation.

Four radiologists reviewed 197 hand and wrist radiographs to determine the usefulness of routine soft-tissue evaluation in the delineation of bony trauma. Soft-tissue changes at four sites in the lateral view were evaluated. Dorsal-hand fat-plane swelling was associated with second through fifth metacarpal fractures (p less than 0.01). Dorsal-wrist fat-plane swelling was associated with carpal fractures and wrist dislocations (p less than 0.01). Pronator and dorsal radial swelling were both associated with forearm fractures and carpal dislocations (p less than 0.01). Soft-tissue changes at five sites in the posteroanterior view were evaluated. Thenar swelling was associated with thumb metacarpal fractures and dislocations (p less than 0.01). Hypothenar swelling was associated with second through fifth metacarpal fractures and dislocations (p less than 0.01). Navicular fat-pad swelling was associated with carpal fractures (p less than 0.01) and strongly suggested a navicular fracture when present. Pararadial swelling was significantly associated with distal radial fractures (p less than 0.01), while paraulnar swelling was significantly associated with ulnar fractures (p less than 0.01). The lateral view of the hand and wrist is useful in compartmentalizing fractures to the hand, wrist, and forearm. Swelling in any compartment should lead to closer evaluation of all bony structures contained within that compartment. The soft tissues found in the posteroanterior view of the hand and wrist help further localize hand and wrist fractures. Additional views should be considered when significant swelling is present in the absence of an obvious fracture or dislocation. When more than one fat plane is unequivocally disturbed, protective immobilization with reexamination in 10 days is recommended.

Adipose Tissue↗
PubMed1984

Murine immunization by cesium-137 irradiation attenuated Schistosoma mansoni cercariae.

Cesium-137, becoming a more readily available ionizing gamma radiation source for laboratory use, was shown to effectively attenuate Schistosoma mansoni cercariae for vaccine production. In parallel comparison studies with the murine model, cesium-137 attenuated cercariae consistently afforded better (P greater than 0.05) protection than did the cobalt-60 prepared vaccine. Dose-response data indicated that the optimal total irradiation with cesium-137 was between 45 and 50 Krad.

Animals↗
PubMed1983

Enhanced survival in Pseudomonas aeruginosa septicemia associated with high levels of circulating antibody to Escherichia coli endotoxin core.

We studied the relationship between serum antibodies to the cross-reactive endotoxin core of Escherichia coli and survival following Pseudomonas aeruginosa septicemia. Core glycolipid was purified from the outer cell membrane of a uridine diphosphate galactose 4-epimerase-deficient rough mutant E. coli (J5 strain), characterized, and used as the antigen in a quantitative enzyme-linked immunosorbent assay (ELISA) to measure core-specific IgG and IgM antibodies. 43 patients with Pseudomonas septicemia, among whom there was a mortality of 42%, were evaluated. Core-specific antibody concentrations in acute sera ranged from 1 to 49 micrograms/ml in the case of IgG and from 1 to 200 micrograms/ml for IgM. Core-specific antibodies of both isotypes were higher in patients who survived compared with those who succumbed to their septicemias (mean, microgram/ml +/- SEM, 26 +/- 3 vs. 14 +/- 4, P = 0.005 for IgG, and 55 +/- 12 vs. 18 +/- 5, P = 0.009 for IgM). Although total IgG levels were also higher in acute sera from survivors compared with nonsurvivors (mean, mg/dl +/- SEM, 1,120 +/- 99 vs. 694 +/- 119, P = 0.004), total IgM levels were virtually identical in the two groups (146 +/- 23 vs. 148 +/- 48, P = 0.52). Conversely, patients with core-specific IgG levels greater than 10 micrograms/ml at the onset of septicemia had better survival than those with levels less than 10 micrograms/ml (79 vs. 14%, P less than 0.001), and patients with core-specific IgM levels greater than 30 micrograms/ml had better survival than those with levels less than 30 micrograms/ml (81 vs. 44%, P = 0.01). In comparison, patients with total IgG levels greater than 1,000 mg/dl also had better survival than those with levels less than 1,000 mg/dl (82 vs. 42%, P = 0.01), while those with total IgM levels greater than 150 mg/dl showed somewhat less improvement in survival compared with those with levels less than 150 mg/dl (71 vs. 50%, P = 0.12). Core-specific IgM was highly correlated with core-specific IgG (r = 0.52), but not with type-specific anti-lipopolysaccharide (r = 0.13) or anti-toxin A (r = 0.12) antibodies, or with total IgG (r = 0.28) or IgM (r = 0.31). In contrast, core-specific IgG correlated somewhat more closely with type-specific antibodies (r = 0.36), and with total IgG (r = 0.51) and IgM (r = 0.52). Stepwise linear discriminant analysis indicated that type-specific antibody levels were the best predictor of outcome, among those antibodies examined, followed by anti-core IgM. Although anti-core IgG, anti-toxin A, and total IgG levels all correlated individually with survival, none augmented the prognostic power of type-specific antibodies in combination with anti-core IgM, which together predicted outcome accurately 73.5% of the time. Host factors not significantly associated with anti-core antibody levels included rapidly fatal underlying disease, age, sex, leukopenia, and prior treatment with cytotoxic drugs. In contrast, prior steroid therapy was associated with low levels of both core-specific IgG and IgM (P < 0.05). These data suggest cross-protective activity against P. aeruginosa septicemia of naturally occurring antibodies to the endotoxin core of E. coli. Anti-core antibodies, particularly of the IgM isotype appear to augment the more specific protective immunity engendered by antibodies to the O-specific side chains of Pseudomonas lipopolysaccharides. This cross-protective immunity likely applies to other Gram-negative pathogens as well.

Antibodies, Anti-Idiotypic↗
PubMed1982

Teaching concepts of clinical measurement variation to medical students.

An exercise in clinical epidemiology was developed for medical students to demonstrate the process and limitations of scientific measurement using models that simulate common clinical experiences. All scales of measurement (nominal, ordinal and interval) were used to illustrate concepts of intra- and interobserver variation, systematic error, recording error, and procedural error. In a laboratory, students a) determined blood pressures on six videotaped subjects, b) graded sugar content of unknown solutions from 0 to 4+ using Clinitest tablets, c) measured papules that simulated PPD reactions, d) measured heart and kidney size on X-rays and, e) described a model skin lesion (melanoma). Traditionally, measurement variation is taught in biostatistics or epidemiology courses using previously collected data. Use of these models enables students to produce their own data using measurements commonly employed by the clinician. The exercise provided material for a meaningful discussion of the implications of measurement error in clinical decision-making.

Clinical Competence↗