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Biomedical subjects

D L Johnson

Publications and source records attributed to D L Johnson.

At least 91 records · Page 5Linked to original sources
PubMed1998

Are mental health services losing out in the US under managed care?

Managed care in its various forms has become a dominating force in US healthcare. For people who have long term serious mental illnesses, this trend has had undesirable consequences. In the US, states that have adopted managed-care systems such as New Mexico, Tennessee and Texas have been harder hit than states that have not chosen managed care. Funds available for services have been reduced, hospital bed days have been shortened, formularies have been limited and number of treatment sessions reduced. A basic problem is that for-profit managed care is more interested in profits than in quality of services.

Humans↗
PubMed1998

Patellar tendon ACL reconstruction and rehabilitation practices and opinions (autograft versus allograft): orthopaedic sports medicine fellowship program survey.

We wanted to determine the bone-patellar tendon-bone (BPTB) anterior cruciate ligament (ACL) reconstruction practices of accredited orthopaedic sports medicine fellowship programs and their opinions about whether differences should exist in rehabilitation protocol, bracing, and timing of release to cutting/agility sports between autogeneic and allogeneic grafts. Our survey showed most programs did 51 to 100 BPTB ACL reconstructions during the 12 months before survey completion. Standard rehabilitation protocols were used without differences based on BPTB graft type or fixation concerns. Programs were equally divided regarding whether BPTB graft type should be a timing of release to cutting/agility sports factor. Programs were almost equally divided regarding routinely prescribed derotation braces. More programs used autograft rather than allograft BPTB tissue for ACL reconstruction, without rehabilitation protocol differences based on graft type or fixation concerns. Conflicting results regarding protocol and timing of release to cutting/agility sports indicate that several factors may contribute to the clinical decision-making process. Equivocal results regarding derotation brace prescription raises concerns regarding their necessity.

Anterior Cruciate Ligament↗
PubMed1998

Urolithiasis in dogs. I: Mineral prevalence and interrelations of mineral composition, age, and sex.

OBJECTIVE: To compile and statistically analyze selected data from a large number of canine urinary calculi. SAMPLE POPULATION: 11,000 specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex. PROCEDURE: Records were used to compile information from all canine calculi analyzed between July 1981 and January 1994. Interrelations of mineral composition, location of specimens within the urinary tract, age and sex of affected dogs, and number of previous episodes of urolithiasis were determined. RESULTS: Approximately 70% of the specimens were from a first episode of urolithiasis. Calculi were located in the urinary bladder of 93.1% of females and 79.0% of males, and in the upper urinary tract of 4% of females and 2% of males. Calculi were found in multiple sites in 23.1% of males and 5.2% of females. Significantly higher proportions of struvite, apatite, and urate were found in uroliths from females; oxalate, cystine, silica, and brushite were significantly more prevalent in males. Sixty-one percent of specimens from males and 29% from females were composed of a single mineral substance. The most common mineral combination of 2 or more minerals included struvite and apatite. An additional 67 specimens from male dogs and 49 from female dogs contained other mineral combinations. In 48% of specimens from males and nearly 62% of specimens from females, the minerals formed several distinct layers of differing composition. CONCLUSIONS: Male and female dogs from urinary calculi composed of 1 or more of several distinct minerals. Prevalence of canine uroliths differs between ages and between the sexes. Many specimens contain complex layering of minerals; most specimens were found in the urinary bladder. CLINICAL RELEVANCE: Sex and age of dogs, mineral types of likely calculi in males versus females, and their anatomic location are important considerations for clinicians when evaluating risk in dogs with urolithiasis.

Age Distribution↗
PubMed1998

Urolithiasis in dogs. II: Breed prevalence, and interrelations of breed, sex, age, and mineral composition.

OBJECTIVE: To analyze selected breed-related data for canine urinary calculi. SAMPLE POPULATION: 11,000 specimens: 5,781 from female dogs, 5,215 from males, and 4 from dogs of unrecorded sex. PROCEDURE: Information was compiled for all canine urinary calculi submitted between July 1981 and January 1994. Results for a mixed-breed group and 26 of the most common breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of affected dogs and mineral composition of the specimens were determined. RESULTS: Prevalence of 5 specific mineral types was significantly correlated between the sexes of 27 common breed groups: struvite, calcium phosphate (apatite), calcium oxalate, brushite, and urate. Struvite-containing calculi were seen in high proportions in both sexes of 7 breeds, and in low proportions in both sexes of 7 other breeds. Male and female Lhasa Apsos, Cairn Terriers, and 5 other breeds had high proportions of oxalate-containing calculi; values in males were substantially higher. Low numbers of oxalate-containing calculi were seen in both sexes of 7 breeds; Dalmatians had the lowest numbers. Males and females of 6 breeds had high numbers of urate-containing calculi, Dalmatians and English Bulldogs had the highest numbers. Low amounts of urate were found in calculi from males and females of 6 breeds, Samoyeds had the lowest numbers. Highest proportions of cystine-containing calculi were seen in male Dachshunds, English Bulldogs, and Chihuahuas. Males of 8 breeds had no specimens that contained cystine; only 2 such specimens were obtained from females. CONCLUSIONS: Prevalence of uroliths differs among breed, age, and sex of affected dogs. CLINICAL RELEVANCE: Breed, sex, and age of dogs; mineral types of calculi in males versus females; and their anatomic location within the tract are important considerations for clinicians when evaluating risk in dogs with urolithiasis and in identifying areas that need further in-depth applied or clinical investigation, or both.

Age Distribution↗
PubMed1998

Urolithiasis in dogs. III: Prevalence of urinary tract infection and interrelations of infection, age, sex, and mineral composition.

OBJECTIVE: To compile and statistically analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis. SAMPLE POPULATION: 11,000 canine urinary calculus specimens. 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex. PROCEDURE: Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding all canine urinary calculus specimens submitted for analysis between July 1981 and January 1994. Interrelations of sex and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically. RESULTS: Urolithiasis was associated with growth of bacteria isolated from urine or calculi, or both, in 65% of females and nearly 44% of males. Staphylococcus intermedius was isolated most often from either sex (54% for females, 30% for males). In addition to staphylococci, 22 other bacterial species were isolated from specimens from females, and 17 other bacterial species and 1 species of yeast were isolated from males. A single bacterial species was isolated from 87.6% of cultures from females and from nearly 90% of cultures from males. Among females, nearly 98% of pure cultures of staphylococci were associated with calculi that contained struvite; this was true for 80% of pure cultures of staphylococci from males. CONCLUSIONS AND CLINICAL RELEVANCE: There are wide sex differences in prevalence of urolithiasis- and specific mineral-associated bacterial infections. In several instances, bacterial infections were significantly related to urinary calculus location. These variables should be considered in any evaluation of canine patients that have uroliths.

Age Distribution↗
PubMed1998

Urolithiasis in dogs. IV: Survey of interrelations among breed, mineral composition, and anatomic location of calculi, and presence of urinary tract infection.

OBJECTIVE: To compile and analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis. SAMPLE POPULATION: 11,000 canine urinary calculus specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex. PROCEDURE: Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding urinary calculus specimens from dogs. Records surveyed were of all canine calculi submitted for analysis between July 1981 and January 1994. Results analyzed included those of a mixed-breed group and 26 common breeds of stone-forming dogs. Interrelations of breed, sex, and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically. RESULTS: Proportions of culture-positive specimens were significantly correlated between the sexes (r = 0.494, P = 0.008). Staphylococcus intermedius was isolated most often from either sex, ranging from 36.1% (Basset Hounds) to 67.9% (Pekingese) of cultured specimens from females and 8.7% (Chihuahuas) to 71.4% (Scottish Terriers) of specimens from males. The second most frequently isolated bacterial species, Escherichia coli, ranged from 0% in males of 2 breeds and females of 4 breeds to 25% in Cairn Terrier males and 19.4% in Basset Hound females. Streptococcus spp were the third most frequently isolated bacterial species. Significant correlations between the sexes were found for percentages of calculi located in the urinary bladder (r = 0.490, P = 0.008), and for calculi voided in the urine (r = 0.503, P = 0.006). CONCLUSIONS: Breed and sex differences in prevalence of urolithiasis- and mineral-associated bacterial infections are numerous. Staphylococcus intermedius was the most common isolate from specimens from all but 3 of 54 breed/sex groupings. For either sex, streptococcal infections were significantly related to proportions of calculi passed in the urine.

Age Distribution↗
PubMed1998

The Wisconsin Primary Care Organizations Consortium: a forum for the primary care medical specialties.

The Wisconsin Primary Care Organizations Consortium (WI-PCOC) is composed of the leadership of Wisconsin's primary care medical specialties whose four professional societies have a combined membership of about 3,900 physicians. Since 1992, WI-PCOC has explored the priorities and issues of importance of each organization, and has reviewed organizational resources to synchronize agendas and to avoid conflict. WIPCOC articulates policy supported by its member societies with a common voice; it does not set policy. WI-PCOC has worked with legislators, medical school deans, other specialty societies and other groups interested in primary care service and education. WI-PCOC member organizations aspire to work together to improve the level of health of Wisconsin citizens and their communities.

Family Practice↗
PubMed1998

Functional MRI statistical software packages: a comparative analysis.

Currently, there are many choices of software packages for the analysis of fMRI data, each offering many options. Since no one package can meet the needs of all fMRI laboratories, it is helpful to know what each package offers. Several software programs were evaluated for comparison of their documentation, ease of learning and use, referencing, data input steps required, types of statistical methods offered, and output choices. The functionality of each package was detailed and discussed. AFNI 2.01, SPM96, Stimulate 5.0, MEDIMAX 2.01, and FIT were tested. FIASCO, Yale, and MEDx 2.0 were described but not tested. A description of each package is provided.

Algorithms↗
PubMed1997

Use of age and serum gamma-glutamyltransferase activity to assess passive transfer status in lambs.

OBJECTIVE: To develop an algorithm for predicting passive transfer status of lambs of various ages, using the lamb's age and serum gamma-glutamyltransferase (GGT) activity. DESIGN: Prospective study. ANIMALS: 51 Suffolk, Columbia, and crossbred lambs from 1 to 16 days old. PROCEDURE: Serum was obtained from all lambs. Serum GGT activity was measured, using a commercially available kit. Serum IgG concentration was determined by use of radial immunodiffusion. Day-1 serum IgG concentration was estimated from sample IgG concentration, lamb age, and the published 14-day half-life of IgG in lambs. Stepwise multivariate regression models were developed to estimate day-1 serum IgG concentration as a function of the natural logarithm of serum GGT activity (In[GGT]) and natural logarithm of lamb age (In[age]) at the time of sampling. These regression models were then used to calculate serum GGT activities that were equivalent to various day-1 IgG concentrations in lambs of various ages. RESULTS: In(GGT) and In(age) were significantly associated with estimated day-1 IgG concentration. Day-1 serum IgG concentration could be predicted using the formula: IgG = -7,686 + 1,366(In[GGT]) + 1,199(In[age]). The model was moderately accurate in predicting serum IgG concentration (R2 = 0.52). CLINICAL IMPLICATIONS: Serum GGT activity can be used to assess passive transfer status of lambs.

Aging↗
PubMed1997

An RNA polymerase III-defective mutation in TATA-binding protein disrupts its interaction with a transcription factor IIIB subunit in drosophila cells.

A subunit of the Drosophila RNA polymerase III transcription factor IIIB (TFIIIB) complex has been identified using antibodies directed against the analogous human protein, hIIIB90. This protein has an apparent molecular mass of 105 kDa and has been designated dTAFIII105. Drosophila S-2 cell extracts that were immunodepleted of dTAFIII105 were substantially reduced in their capacity to support tRNA gene transcription. A protein (far Western) blot analysis revealed that dTAFIII105, present in a TFIIIB fraction, directly interacts with TATA-binding protein (TBP). Coimmunoprecipitation assays demonstrated that this protein associates with TBP in S-2 cell extracts. Our previous studies have identified a mutation at position 332 within Drosophila TBP that changes a highly conserved arginine residue to a histidine residue, which renders it specifically defective in its ability to support RNA polymerase III transcription in S-2 cells (Trivedi, A., Vilalta, A., Gopalan, S., and Johnson, D. L. (1996) Mol. Cell. Biol. 16, 6909-6916). We further demonstrate that extracts prepared from a stable cell line expressing epitope-tagged wild-type TBP exhibit an increase in tRNA gene transcription, whereas extracts derived from cells expressing the mutant TBP protein do not. Coimmunoprecipitation assays and far Western blot analysis demonstrate that this mutation in TBP abolishes its ability to stably interact with dTAFIII105. Thus, we have identified both a Drosophila protein that is directly associated with TBP in the TFIIIB complex, dTAFIII105, and an amino acid residue within the highly conserved carboxyl-terminal region of TBP that is critical for dTAFIII105-TBP interactions.

Animals↗
PubMed1997

Mutagenesis studies of the human erythropoietin receptor. Establishment of structure-function relationships.

Mutagenesis of the erythropoietin receptor (EPOR) permits analysis of the contribution that individual amino acid residues make to erythropoietin (EPO) binding. We employed both random and site-specific mutagenesis to determine the function of amino acid residues in the extracellular domain (referred to as EPO binding protein, EBP) of the EPOR. Residues were chosen for site-specific alanine substitution based on the results of the random mutagenesis or on their homology to residues that are conserved or have been reported to be involved in ligand binding in other receptors of the cytokine receptor family. Site-specific mutants were expressed in Escherichia coli as soluble EBP and analyzed for EPO binding in several different assay formats. In addition, selected mutant proteins were expressed as full-length EPOR on the surface of COS cells and analyzed for 125I-EPO binding in receptor binding assays. Using these methods, we have identified residues that appear to be involved in EPO binding as well as other residues, most of which are conserved in receptors of the cytokine receptor family, that appear to be necessary for the proper folding and/or stability of the EPOR. We present correlations between these mutagenesis data and the recently solved crystal structure of the EBP with a peptide ligand.

Amino Acid Sequence↗
PubMed1997

Fatigue after eccentric quadriceps femoris work produces earlier gastrocnemius and delayed quadriceps femoris activation during crossover cutting among normal athletic women.

Athletic women are at greater risk of anterior cruciate ligament (ACL) injury than men. Twenty, healthy, athletic women were evaluated for the effect of preferred stance limb isokinetic quadriceps femoris and hamstring fatigue from eccentric work compared with controls on the activation onset of vastus medialis, rectus femoris, vastus lateralis, the medial hamstrings, biceps femoris, and gastrocnemius muscles. Following 3 weeks of crossover cut training, subjects were tested for fatigue effects (5 subjects/week, 3 conditions, 1 condition/day, order effect controlled) on muscle activation onsets prior to crossover cut landing heelstrike (mixed model, ANOVA, P < 0.05). Fatigue from eccentric quadriceps femoris work produced delayed vastus medialis (P = 0.03), rectus femoris (P = 0.007), and vastus lateralis (P = 0.03) activation onsets compared with control, but did not differ compared to hamstring fatigue. Neither hamstring nor quadriceps femoris fatigue produced differences (P > 0.05) in medial hamstring or biceps femoris activation onsets compared to control. Quadriceps femoris fatigue from eccentric work produced earlier gastrocnemius activation onsets (P = 0.048) than control, but did not differ for hamstring fatigue. The gastrocnemius appears to provide synergistic and compensatory dynamic knee stabilization in closed kinetic chain function during quadriceps femoris fatigue. This finding in a normal group at high risk of ACL injury while performing a maneuver with a high ACL injury risk supports gastrocnemius inclusion in knee rehabilitation and conditioning programs and suggests the need for comparative evaluations of knee injured/reconstructed subjects.

Analysis of Variance↗
PubMed1997

Intervertebral disc space inflammation in children.

Discitis in children commonly presents with fever, back pain, irritability, and an inability to walk. An elevated ESR and characteristic changes on plain X-rays or bone scan are sufficient for diagnosis, but MRI is more sensitive and more specific, and it shows pathologic changes earlier. Intravenous antibiotics are administered when cultures of the disc space are positive, but in more than half of the cases, no organism can be grown. Symptoms are alleviated with bed-rest or external orthoses, but neither the duration nor the kind of symptomatic treatment influences outcome.

Anti-Inflammatory Agents↗
PubMed1997

Lased and sandblasted denture base surface preparations affecting resilient liner bonding.

STATEMENT OF PROBLEM: Adhesive failure between the liner and the denture base creates an environment for potential bacterial growth and accelerated breakdown of the soft liner resulting in a deteriorating prosthesis. PURPOSE: This study evaluated the effects of a specific sandblasted or lased preparation on the interfacial bonding of polymethyl methacrylate and silicone and polyethyl methacrylate resilient liners. MATERIAL AND METHODS: Polymethyl methacrylate test specimens were fabricated and received one of three surface treatments: untreated (control), sandblasted (250 microns aluminum oxide particles), and lased (carbon dioxide). Polyethyl methacrylate and silicone resilient lining materials were applied to these surfaces and the peel strengths were determined with the American Society for Testing and Materials peelin-adhesion test. RESULTS: Altering the polymethyl methacrylate surface by sandblasting significantly reduced the peel strengths for the polymethyl methacrylate/polyethyl methacrylate and polymethyl methacrylate/silicone specimens. Altering the polymethyl methacrylate surface by delivering carbon dioxide laser energy to form a grid pattern produced lower peel strengths that were statistically significant from the controls for the polymethyl methacrylate/polyethyl methacrylate specimens, but not so for the polymethyl methacrylate/silicone specimens. Untreated polymethyl methacrylate/polyethyl methacrylate peel strengths were significantly higher than polymethyl methacrylate/silicone. CONCLUSIONS: Results of this study imply that mechanical surface preparation of denture bases before application of a resilient liner may not be warranted.

Adhesiveness↗
PubMed1997

Overview of severe mental illness.

The severe mental illnesses are psychiatric disorders characterized by their persistence and extensive disability. Classification of these disorders has seen improved reliability, but problems remain with validity. Etiological formulations emphasize the biological origins of the disorders, but psychological factors, chiefly in the area of stress, are recognized as important in the management of relapse. Psychological features, especially those apparent during psychotic episodes, make the disorders particularly difficult to treat. Patients tend to be noncompliant. In addition, these features dispose people with severe mental illnesses to behaviors that place them at risk for HIV and other catastrophic illnesses. New psychopharmacological treatments may improve compliance and reduce relapse, but none has made psychosocial treatments unnecessary. Progress in developing effective treatments has been slow, but prospects are encouraging.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Stress fractures. Clinical history and physical examination.

The incidence of stress fractures is increasing among competitive and recreational athletes as well as among children and the elderly. By understanding the continuum of bone's response to stress and maintaining an appropriate index of suspicion, the health care provider can diagnose these injuries appropriately. An accurate history and examination is essential and will differentiate stress fractures from other stress reactions. The more common stress fractures are discussed.

Bone and Bones↗