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Biomedical subjects

D K Smith

Publications and source records attributed to D K Smith.

At least 91 records · Page 5Linked to original sources
PubMed1993

Injuries to preschool-age children in day-care centers. A retrospective record review.

OBJECTIVES: To increase our understanding of the epidemiologic nature of injuries to children in day-care settings by examining injury logs and to determine appropriate methods for calculating injury rates. DESIGN: Retrospective, with data collected through a review of 1 year's records. SETTING: Four suburban day-care centers in the upper Midwest. PARTICIPANTS: Five hundred twenty-seven preschool-age children, 275 of whom experienced one or more injuries during the study period. SELECTION PROCEDURE: Convenience sample. MEASUREMENTS/RESULTS: Injury rates were calculated based on the number of hours spent in day care in the study year. More than 1000 injuries were reported for 527 children. Injury rates ranged from 0.006 to 0.049 per child per standardized 8-hour day in a day-care center (or six to 49 injuries per 1000 children per 8 hours of exposure). However, most injuries were minor, and none resulted in a fatality or hospital admission. Using this method, injury rates were examined by gender and month. CONCLUSIONS: Future research should determine exposure time based on the actual number of hours a child spends in attendance to determine injury rates. Exposure time should also be carefully considered in determining product- and location-specific rates of injury.

Abstracting and Indexing↗
PubMed1993

Laparoscopic injection of fibrin glue to arrest intraparenchymal abdominal hemorrhage: an experimental study.

The laparoscope offers a novel avenue for the diagnosis of intra-abdominal injury and the use of fibrin glue (FG) as a treatment for hemorrhage in trauma patients. This study was undertaken to assess the practicality and effectiveness of FG injection under laparoscopic direction to arrest hemorrhage in solid viscera. Twenty dogs were randomized into a control group (CG) and a treatment group (TG). All animals underwent laparotomy to surgically induce uniform injuries to the hepatic and splenic parenchyma. The TG animals (n = 12) were allowed to hemorrhage for 30 minutes. The injuries were then visualized and FG injected intraparenchymally under laparoscopic direction. The average duration of the procedure was 25 minutes (range, 15-50). No hemostatic interventions were performed on the CG animals (n = 8). Mortality in the CG was 63% (5 of 8); there were no deaths in TG animals prior to sacrifice. Necropsy of TG animals revealed progressively healing hepatic and splenic injuries with no gross evidence of pulmonary FG emboli, intraparenchymal microemboli, or increased adhesion formation. No other complications were noted. This study demonstrates that hemorrhage from the liver and spleen can be successfully controlled using the laparoscope to direct the intraparenchymal injection of FG. In this experimental model, the procedure can be performed expeditiously. It is associated with reduction of mortality to zero when compared with controls. No complications associated with laparoscopy or FG injection were recognized. This technique may have potential for application in the management of stable patients who manifest evidence of intraperitoneal hemorrhage as a result of solid organ injury.

Animals↗
PubMed1993

Anatomic features of the carpal scaphoid: validation of biometric measurements and symmetry with three-dimensional MR imaging.

The goals of reconstructive surgery for scaphoid fracture nonunions include restoration of normal scaphoid length and shape by use of the contralateral scaphoid bone as a geometric model. A literature search revealed limited documentation of normal biometric measurements and no validation of scaphoid anatomic symmetry. A study was performed to provide normative data and evaluate the right-to-left symmetry of specific geometric measurements of the scaphoid. One hundred normal carpal scaphoid bones in 30 healthy subjects and 40 patients were examined with three-dimensional magnetic resonance (MR) imaging. Standardized oblique projections were reconstructed from each three-dimensional data set, and seven biometric measurements of each scaphoid were obtained. Normative data from the study group were obtained by means of analysis of all 100 scaphoids. Right-to-left symmetry was validated with the biometric measurements of both scaphoids in the healthy subjects. These data validate scaphoid symmetry and provide 95% confidence intervals for specific biometric measurements that are used for preoperative planning of surgical reconstruction of scaphoid nonunions.

Adolescent↗
PubMed1993

Dorsal carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging.

OBJECTIVE: Three-dimensional Fourier transform MR imaging techniques can produce much thinner contiguous slices than are obtainable with standard two-dimensional Fourier transform MR imaging techniques. The improved spatial resolution and capabilities for interactive multiplanar displays allow improved visualization of small, complex anatomic structures such as the carpal ligaments. The purposes of this study were twofold: (1) to determine if the dorsal carpal ligaments can be visualized consistently with three-dimensional Fourier transform MR imaging techniques with multiplanar reconstructions and (2) to evaluate the size, shape, orientation, and right-to-left symmetry of the dorsal carpal ligaments in both wrists of 25 asymptomatic volunteers as a basis for future comparison when patients with suspected ligament injuries are seen. SUBJECTS AND METHODS: Both wrists of 25 asymptomatic volunteers were imaged with a three-dimensional Fourier transform MR imaging technique with commercially available equipment. A three-dimensional graphic workstation was used to reconstruct oblique two-dimensional images in the long axes of the radiotriquetral and dorsal intercarpal ligaments in all 50 wrists. The size, shape, orientation, and right-to-left symmetry were determined by the author using the reconstructed two-dimensional images. RESULTS: The radiotriquetral ligament and dorsal intercarpal ligament were visualized in all 50 wrists. The radiotriquetral ligament consisted of a single band arising from the distal radius (next to Lister's tubercle) in 84% and had dual origins from the styloid process of the radius and Lister's tubercle in 16%. The dorsal intercarpal ligament consisted of a single broad band in 14% of wrists, was a branched structure with separate triquetroscaphoid and triquetrotrapezial fascicles in 44%, had completely separate triquetroscaphoid and triquetrotrapezial fascicles in 38%, and had a triquetrotrapezial fascicle larger than the triquetroscaphoid fascicle in 4%. The dorsal intercarpal ligamentous anatomy was symmetric in 16 of 25 volunteers. CONCLUSION: The major dorsal carpal ligaments can be visualized consistently when using three-dimensional Fourier transform MR imaging techniques and multiplanar reconstructions. The dorsal carpal ligaments are usually symmetric in size and morphology; therefore, MR images of the contralateral wrist may be used for comparison with MR images of a patient's injured wrist. The size and shape of the dorsal carpal ligaments are described for comparison with findings in patients who have suspected ligamentous injuries.

Adolescent↗
PubMed1993

Volar carpal ligaments of the wrist: normal appearance on multiplanar reconstructions of three-dimensional Fourier transform MR imaging.

OBJECTIVE: Three-dimensional Fourier transform MR imaging techniques can produce much thinner contiguous slices than are obtainable with standard two-dimensional Fourier transform MR imaging techniques. The improved spatial resolution and capabilities for interactive multiplanar displays allow better visualization of small, complex anatomic structures, such as the carpal ligaments. The purposes of this study were twofold: (1) to determine if the volar carpal ligaments can be consistently visualized when using three-dimensional Fourier transform MR imaging techniques with multiplanar reconstructions and (2) to evaluate the size, shape, orientation, and right-to-left symmetry of the volar carpal ligaments in both wrists of 25 asymptomatic volunteers as a basis for future comparison when patients with suspected ligament injuries are seen. SUBJECTS AND METHODS: Both wrists of 25 asymptomatic volunteers were imaged with a three-dimensional Fourier transform MR imaging technique with commercially available equipment. A three-dimensional graphic workstation was used to reconstruct oblique two-dimensional images in the long axes of the major volar carpal ligaments. The size, shape, orientation, and right-to-left symmetry of the ligaments were determined from the reconstructed two-dimensional images. RESULTS: Six of the eight volar ligaments were visualized in more than 95% of the 50 wrists: the radioscaphocapitate, radiolunotriquetral, radiolunate, ulnolunate, ulnotriquetral, and triquetroscaphoid ligaments. The radioscaphoid and radioscapholunate ligaments were less well defined and were recognizable as ligaments in only 66% and 26% of wrists, respectively. CONCLUSION: The major volar carpal ligaments can be visualized consistently with three-dimensional Fourier transform MR imaging techniques and multiplanar reconstructions. The volar carpal ligaments are usually symmetric between the right and left sides; therefore, MR images of a patient's injured wrist can be compared with MR images of the contralateral wrist. The size and shape of the volar carpal ligaments shown in this article can be used as a basis for comparison when patients with suspected ligamentous injuries are examined. This information will be useful for detecting ligamentous injuries on MR images.

Adult↗
PubMed1992

Transtriquetral perihamate ulnar axial dislocation and palmar lunate dislocation.

Transtriquetral perihamate ulnar axial dislocation associated with palmar lunate dislocation is a rare condition. We could find no other similar cases reported. The mechanism of injury was a combined anteroposterior crushing force that caused axial disruption of the carpus and the metacarpals and wrist hyperextension that caused the transtriquetral lunate dislocation. Our patient was treated with open reduction and internal fixation with good result.

Adult↗
PubMed1992

Vitamin A in hypercholesterolemia.

This study evaluated the relationship between plasma vitamin A and cholesterol in 48 patients with hypercholesterolemia studied before and after treatment with a cholesterol-lowering diet, with or without lipid-lowering medication. Plasma vitamin A levels were higher in hypercholesterolemic subjects than in healthy controls (2.58 +/- 0.15 vs. 1.82 +/- 0.14 mmol/L, p = 0.025) despite similar values for retinol binding protein (RBP). Successful cholesterol lowering, defined as greater than 25% reduction in low density lipoprotein cholesterol, was achieved in 16 patients. In this subset, plasma vitamin A declined from 3.00 +/- 0.32 (pretreatment) to 2.34 +/- 0.15 mmol/L (post treatment; p = 0.018). A nonsignificant increase in RBP was observed, resulting in a significant decrease in the molar ratio of vitamin A to RBP (1.05 +/- 0.06 vs. 0.80 +/- 0.05, p = 0.013). These data suggest an interaction between vitamin A and cholesterol that is independent of the transport mechanisms for vitamin A in association with chylomicrons (post absorptive) and with RBP. Further examinations of the form or forms of vitamin A (retinol, retinyl ester), its distribution within the plasma lipoproteins, and the mechanisms of origin and removal are warranted to explain these findings.

Anticholesteremic Agents↗
PubMed1992

Escherichia coli has two homologous glutamate decarboxylase genes that map to distinct loci.

Degenerate oligonucleotides based on the published Escherichia coli glutamate decarboxylase (GAD) protein sequence were used in a polymerase chain reaction to generate a DNA probe for the E. coli GAD structural gene. Southern blots showed that there were two cross-hybridizing GAD genes, and both of these were cloned and sequenced. The two GAD structural genes, designated gadA and gadB, were found to be 98% similar at the nucleotide level. Each gene encoded a 466-residue polypeptide, named, respectively, GAD alpha and GAD beta, and these differed by only five amino acids. Both GAD alpha and GAD beta contain amino acid residues which are highly conserved among pyridoxal-dependent decarboxylases, but otherwise the protein sequences were not homologous to any other known proteins. By restriction mapping and hybridization to the Kohara miniset library, the two GAD genes were located on the E. coli chromosome. gadA maps at 4046 kb and gadB at 1588 kb. Neither of these positions is in agreement with the current map position for gadS as determined by genetic means. Analysis of Southern blots indicated that two GAD genes were present in all E. coli strains examined, including representatives from the ECOR collection. However, no significant cross-hybridizing gene was found in Salmonella species. Information about the DNA sequences and map positions of gadA and gadB should facilitate a genetic approach to elucidate the role of GAD in E. coli metabolism.

Amino Acid Sequence↗
PubMed1992

HIV disease as a cause of death for African Americans in 1987 and 1990.

Using death certificate data for 1987 and 1988 from the National Center for Health Statistics, combined with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) surveillance data through December 1990 from the Centers for Disease Control, this article reports ranked mortality causes as a measure of the impact of the HIV epidemic within the African-American community. In 1987, while HIV/AIDS ranked 15th as a cause of death for all Americans, for African Americans the disease ranked 10th overall (third for African-American men, fifth for African-American women between 25 and 34 years of age, and ninth for African-American children ages 0 to 14). By 1990, it can be estimated that for all Americans HIV disease was the eight leading cause of death, but for African-Americans it ranked sixth overall. For African-American men between the ages of 35 and 44, HIV disease became the leading cause of death, accounting for 23.5% of all deaths. This disease was the second leading cause of death for African-American men and women between the ages of 25 and 35, and the eighth leading cause of death for African-American children ages 0 to 14. The implications of these findings are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Physician's and dietitian's role in obese care.

In the Surgeon General's Report on Nutrition and Health, of the ten leading causes of death in the United States, five are nutrition related. Instead of nutritional deficiencies as seen in the 1940s, the national diet has shifted to dietary excesses and imbalances. Dietary excesses and imbalances are reflected in obesity, a major health problem affecting approximately 30% of the United States' population. Unfortunately, the diet industry is not regulated and, hence, patients have many avenues from which to choose. Many of these leave patients lost and confused as to why they have failed in maintaining their weight loss. It is well documented that the recidivism rate in the obese is high with only 5% maintaining their weight loss after one year. The following is a review of the physician's and dietitian's roles in long-term weight maintenance.

Dietetics↗
PubMed1992

Community resources in obese care.

Community resources can augment care provided by physicians and dietitians for the obese. The well-distributed community resources in Florida are reviewed. They are well-established and provide emotional support, peer group dynamics, a variety of formats and prices, and information about food and life-style changes.

Humans↗
PubMed1990

External fixation of high-energy upper extremity injuries.

Forty patients with high-energy upper extremity injuries involving the humerus and forearm bones were treated by primarye external fixation. Concomitant soft tissue or neurovascular injuries were rated by the Gustilo classification, and this rating correlated well with the final results: three fractures were Gustilo type I, two fractures were type II, and 35 were type III (IIIA, nine fractures; IIIB, eight; and IIIC, 18). Immediate external fixation, open wound treatment, delayed bone grafting, and late internal fixation led to good to excellent results in 73%. Complications were either minor (related to the external fixation and included pin loosening, 20%) or significant (osteomyelitis, 3%).

Adolescent↗
PubMed1990

Acoustic reflectometry for assessment of hearing loss in children with middle ear effusion.

We sought associations between acoustic reflectometry and hearing loss in ears with and without middle ear effusion in 137 New Zealand children ages 3 to 16 years. Reflectometry was significantly associated with conductive hearing loss. These associations were present in the entire sample; correlation coefficients varied between 0.31 at 2000 Hz (P less than 0.001) and 0.55 for a three frequency pure tone average (P less than 0.001). The associations persisted for the sample of ears deemed to be filled entirely by effusion; correlation coefficients varied between 0.27 at 4000 Hz (P = 0.026) and 0.47 at 500 Hz (P less than 0.001). Using a reflectivity of 6.0 or greater to detect a three frequency pure tone average loss of 30 dB or more, the sensitivity was 88% and the specificity was 44%. The technique of acoustic reflectometry should be explored and extended to permit rational decisions about management of middle ear effusions.

Adolescent↗
PubMed1990

The knee after partial meniscectomy: MR imaging features.

The magnetic resonance (MR) examinations of 51 menisci treated by means of partial meniscectomy were reviewed. Menisci were divided into three groups: group 1, near normal length without osteoarthritis; 2, substantially shortened without osteoarthritis; and 3, any length with osteoarthritis. Group 1 menisci resembled normal menisci except for mild shortening and frequent signal inhomogeneity (56%). Group 2 menisci varied in appearance, with marked contour irregularity simulating fragmentation in 40% of segments despite a normal postoperative appearance at follow-up arthroscopy. Group 3 menisci appeared similar to menisci of the same length without osteoarthritis. Arthroscopic correlation, available for 23 menisci (45%), confirmed the MR diagnosis of a tear in 11 and no tear in 49 and revealed an unsuspected tear in three meniscal segments. There is a spectrum of normal MR appearances after partial meniscectomy. Standard MR criteria can be used to diagnose tears in the absence of marked contour irregularity; however, the diagnosis of tears of segments with marked contour irregularity must be made cautiously, since this irregularity can mimic a tear and was not predictive of an arthroscopically visible tear.

Adolescent↗
PubMed1990

Dorsal lunate tilt (DISI configuration): sign of scaphoid fracture displacement.

Excessive dorsiflexion (dorsal tilting) of the lunate on a lateral wrist radiograph can be an important sign of carpal injury. Lunate dorsiflexion is a well-recognized sign of an intercarpal ligamentous injury pattern known as dorsal intercalated segment instability (DISI). It is less well recognized that excessive dorsal tilting of the lunate (DISI configuration) can also be produced by displacement of a scaphoid waist fracture. Since the management and prognosis of displaced scaphoid fractures may be quite different from those for nondisplaced fractures, radiologists can make an important contribution by recognizing dorsal tilting of the lunate and appreciating that it may be an important, indirect sign of scaphoid fracture displacement, which may not be directly visualized with standard wrist radiography. In this setting, computed tomography or complex motion tomography may be helpful for further evaluation of the scaphoid fracture.

Aged↗
PubMed1990

Subtalar arthrosis: evaluation with CT.

The surgical implantation of a Silastic wedge into the lateral subtalar joint (subtalar arthrosis) is designed to restrict the osseous malalignment associated with a flexible or neurogenic flatfoot deformity. We used CT to examine patients who had persistent pain after a subtalar arthrosis and retrospectively reviewed our experience with CT scans of 13 subtalar implants (seven patients) during a 3.5-year period. The CT scans of four asymptomatic subtalar implants showed each implant in the expected position and orientation, and the findings were considered normal. Conversely, the findings on CT scans of all nine painful implants (seven patients) were interpreted as abnormal. The scans showed oblique orientation of four implants (44%), loosening of three implants (33%), extruded methyl methacrylate in the subtalar joint in two implants (22%), and abnormal calcaneal recession in two implants (22%). Five of the nine painful implants were revised with improvement or resolution of symptoms. Our experience suggests that CT scanning of the subtalar joint can show the position and orientation of a subtalar implant and identify causes of persistent pain after a subtalar arthrosis.

Adolescent↗
PubMed1989

Phylogenetic comparative analysis and the secondary structure of ribonuclease P RNA--a review.

The most incisive a priori approach to inferring the higher order structure of large RNAs has proven to be the use of phylogenetic comparisons. This article provides guidelines to the method, using as an illustration the elucidation of the secondary structure of the catalytic RNA subunit of ribonuclease P (RNase P). The resultant structure is compared to the possibilities that are predicted thermodynamically for the RNase P RNA sequences of nine eubacteria.

Bacillus subtilis↗