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Biomedical subjects

D N Collins

Publications and source records attributed to D N Collins.

At least 37 records · Page 2Linked to original sources
PubMed1991

Cervical spine instability in rheumatoid patients having total hip or knee arthroplasty.

The records and roentgenographs of 113 rheumatoid patients treated by total hip or knee arthroplasty were analyzed retrospectively. The cervical spine roentgenographs were evaluated for significant atlantoaxial subluxation, atlantoaxial impaction, and subaxial subluxation. One or more of these findings were present in 69 (61%) of the patients. Thirty-five of the 69 (50%) with roentgenographically documented cervical spine instability had no signs or symptoms of instability at the time of admission for joint replacement. This high incidence of cervical spine instability in a select population of rheumatoid patients emphasizes the importance of preoperative evaluation of the cervical spine including flexion and extension lateral roentgenographs.

Adolescent↗
PubMed1991

Chronic rupture of the Achilles tendon: a new technique of repair.

A new operative technique is described for the treatment of patients who have a rupture of the Achilles tendon. The large gap between the proximal and distal stumps of the Achilles tendon in seven patients was bridged by use of the tendon of the flexor digitorum longus as the graft. At the most recent follow-up examination (average follow-up, thirty-nine months; range, two to six years), the result was excellent or good in six patients and fair in one. Postoperatively, two patients needed an adjuvant procedure: one, a local rotation flap and the other, a split-thickness skin graft. Both patients had excellent restoration of function. The patient who had a fair result had a persistent limp and residual discomfort. There were no re-ruptures.

Achilles Tendon↗
PubMed1991

Porous-coated anatomic total knee arthroplasty. A prospective analysis comparing cemented and cementless fixation.

The results of 26 cementless porous-coated anatomic (PCA) total knee arthroplasties (TKAs) were analyzed and compared to 25 cemented PCA TKAs. Identical prospective protocols were followed. The mean preoperative and postoperative knee scores at an average three-year follow-up interval (range, two to five years) were 59.6 and 81.5 for cementless knees compared to 57.6 and 80.4 for cemented knees. The difference was not statistically significant (p greater than 0.10). Blood loss was significantly higher in the cementless knees (p = 0.02). Radiolucent lines, loose beads, and tibial component subsidence were more frequent in cementless knees. No differences between cementless and cemented knees were observed in the femoral components. The PCA femoral components implanted without cement compare favorably to those implanted with cement. The PCA tibial and patellar components are more reliably secured with cement.

Adult↗
PubMed1990

Successful use of reaming and intramedullary nailing of the tibia.

The records and radiographs of 87 patients with 88 fractures of the tibial diaphysis who underwent intramedullary reaming and nailing were retrospectively reviewed. The mean patient age was 37 years. Seventy fractures were closed, and 18 were open. The indications for nailing were failures of closed treatment (n = 48), nonunions (n = 24), multiple injuries (n = 14), and fixation of osteotomy (n = 2). Seventy-six patients with 77 nails who were followed for an average of 26.2 months were studied. For acute fractures, the average time to complete clinical and radiographic union was 5.3 months. For established nonunions, the average healing time was 9 months. The only fractures that failed to unit were nonunions developing from previously open Type III injuries. Angular deformities greater than 5 degrees did not occur. Significant tibial shortening occurred in only one fracture. Decreased motion in the ankle or knee was present in six patients. Major complications as a result of tibial nailing occurred in three patients: two deep infections and one patellar tendon rupture. Minor complications included 10 patients with pain at the nail insertion site necessitating removal in four patients, three patients with transient sensory peroneal nerve dysesthesias, and one patient with a superficial wound infection that cleared with local care. Nine patients required reoperation. Intramedullary reaming and nailing of the tibia can be used advantageously in the treatment of difficult fractures of the tibial shaft and their sequelae. Attention to the technical details of nail insertion will minimize the most frequent complications.

Adult↗
PubMed1990

Standard specimens for stain calibration: application to Romanowsky-Giemsa staining.

Standardized specimens with reproducible staining properties were fabricated from extracts of biological objects (bovine liver, nucleoprotamine and defatted muscle). The standard specimens were stained with two formulations of the Romanowsky-Giemsa stain (RG), using the same azure B and eosin Y. One formulation used methanol and Sorensen's buffer and the other DMSO and Hepes buffer as solvents. The standard specimens were stained either in the composite stain or in the individual dyes dissolved in the same solvents and at the same concentration as the composite stain. Solution spectroscopy demonstrated different spectra for the two formulations with some wavelength regions varying by more than an order of magnitude. The RG spectra were also very different from those of the individual dyes dissolved at the RG concentration in the respective solvents. The stained standard specimens were analyzed by microspectrophotometry and were found to have spectra similar to those of cell smears. Furthermore, the standard specimens were shown to be a repeatable substrate for stain uptake. The transmitted light intensity from random fields of the same standardized specimen varied +/- 5%. When specimens were stained at the same time, the specimen-to-specimen variation depended on preparation conditions and the measurement wavelength, but was as good as +/- 5% for some conditions. The quantitative stain performance of both formulations was studied and compared. The standardized specimens provide a tool for the quantitative study of staining processes and specimen preparation procedures and for stain calibration.

Animals↗
PubMed1989

Optimum specimen positioning in the electron microscope using a double-tilt stage.

Optimal imaging of complex structures requires proper alignment relative to the optic axis of the electron microscope. This is especially important for high-voltage and intermediate-voltage microscopes, which form an in-focus image throughout the entire thickness of the object. As a result, structures at different specimen heights form overlapping and confused images that severely curtail the usefulness of these instruments. The work described here provides a generalized, flexible method for optimizing specimen orientation and eliminating or limiting image overlap by means of a commonly used double-tilt stage. Analysis of the motion about the two axes provides accurate tilting for any azimuthal direction whether or not it corresponds to a mechanical axis of the stage. An object can be positioned to minimize image overlap, to record stereopairs for any parallax axis, and to record three-dimensional data sets by the conical collection geometry. Images of muscle paracrystals are shown after tilting about an axis perpendicular to a symmetry direction. The tilted image displays higher-order symmetry, which is altered by changes of one degree. Precision double-tilting for optimizing stereopairs is shown for a desmosome recorded using different parallax axes and pretilts. A tomographic conical data-collection scheme is demonstrated by imaging a microtubule axoneme for a specific cone half-angle and arbitrary azimuthal angles.

Microscopy, Electron↗
PubMed1989

Quality assurance in cytology: New York State Proficiency Testing Program.

The New York State Proficiency Testing Program in Cytology is a three-part program consisting of an annual inspection, biennial proficiency tests, and ongoing education programs. Clinical laboratory consultants inspect laboratories' internal quality control and compliance with regulatory standards. In the proficiency test, cytotechnologists screen test slides and cytopathologists make final diagnostic interpretations. The program promotes professional competence through continuing educational courses and remedial training. Data from a 1988 study that examined test results from the July 1, 1986 to June 30, 1988 test period show that 93.9% of test participants agreed with the correct reference answer.

Cell Biology↗
PubMed1989

Open joint injuries. Classification and treatment.

Experience with wounds involving the major joints of the lower extremity suggests that the extracapsular soft tissues and the intracapsular structures should be considered individually to assess accurately the magnitude of injury and to provide a prognosis. A classification scheme is proposed to characterize the areas and types of injury. Type I open joint injuries are single penetrations without extensive soft-tissue damage, permitting uncomplicated joint and wound closure. Type II injuries are single or multiple penetrations with extensive soft-tissue disruptions (flaps, avulsions, degloving), often requiring secondary operations to attain closure. Type III injuries are open periarticular fractures with extension through the adjacent intraarticular surface. Type IV injuries are open dislocations or those with associated nerve or vascular injury requiring repair. The extent of intraarticular injury further subdivides Types I, II, and III. The prognosis for functional impairment correlates with the severity of injury. The cornerstones for successful management are debridement, antibiotic therapy, properly timed and performed joint closure, and aggressive treatment of the associated bony injury.

Adult↗
PubMed1988

Coccidioidomycosis of the knee with a 26-year follow-up evaluation. A case report.

A case of coccidioidomycosis of the knee caused by the fungus Coccidioides immitis demonstrates the chronicity of this disease as well as the disability incurred. The patient was completely asymptomatic for 11 years after initial treatment but developed progressive joint destruction, disabling pain, and loss of function. The nature of fungal infections in bone and joint necessitates long-term follow-up evaluation, even with adequate surgical debridement and medical therapy.

Arthritis, Infectious↗
PubMed1987

Group C streptococcal arthritis. A case report of equine transmission.

Presented is the third known case of a group C streptococcal arthritis, this case documented in a healthy 42-year-old horse trainer, apparently transmitted by a mare. After a delayed diagnosis, the patient responded favorably to surgical drainage and parenteral penicillin G, but required a manipulation of his knee under general anesthesia. Although rare, group C streptococcal arthritis can occur in hosts with no apparent predisposing factors. Frequent exposure to farm animals may increase the risk.

Adult↗
PubMed1987

Standard specimens for stain calibration and their application to the Papanicolaou stain.

Standardized specimens composed of extracts of biologic objects (nucleoprotamine and bovine liver) were developed as tools for the quantitative evaluation of stain performance on biologic substrates. The specimens are mixtures of proteins and nucleic acids and thus mimic the staining characteristics of cytologic smears. The concentration of each mixture and the specimen thickness can be precisely controlled, ensuring the production of a large number of samples with a nearly identical capability for dye binding. The transmitted light spectra of the standardized specimens varied depending on the extract and the preparation conditions. Spectra similar to those reported from the nuclei and cytoplasm of cell types in Papanicolaou-stained cervicovaginal smears were observed. Light transmission was uniform to +/- 5% across each specimen and from specimen to specimen. The specimen thickness was uniform within +/- 2%. Studies with these standardized samples could reveal the much-needed correlations between the chemical and optical characteristics of dyes and dye solutions and the performance of the dyes on biologic substrates.

Animals↗
PubMed1987

The use of the vastus lateralis flap in patients with intractable infection after resection arthroplasty following the use of a hip implant.

Recurrent sepsis and breakdown of the tissues in the operative wound after resection arthroplasty is performed for a hip with an infection at the site of an implant present a formidable challenge. A review of the literature indicates that more than 25 per cent of patients had delayed healing, additional surgery, or persistent drainage after resection arthroplasty. Under these circumstances, muscle flaps may help provide definitive closure, cessation of drainage, and functional recovery of the extremity as well as a reduction in the length and cost of hospitalization. The successful use of a vastus lateralis flap in seven patients is described. The specific advantages are: the flap has a consistent reliably identified vascular pedicle which permits a wide arc of rotation; sufficient muscle volume enables large open wounds to be filled; the structural integrity of the muscle is not violated by previous operations; and no important functional deficit is attributable to the procedure.

Drainage↗
PubMed1985

Alterations in guinea pig hepatocytes exposed to chlorinated hydrocarbons: membrane proliferation and excretion.

Polychlorinated aromatic hydrocarbons are a widespread, extremely toxic group of environmental pollutants. A fine soot containing a mixture of these compounds contaminated an office building after a fire involving an electric service transformer and its polychlorinated biphenyl (PCB) containing cooling fluid. The soot was found to contain polychlorinated dibenzo-p-dioxins (PCDD), and dibenzofurans (PCDF). Guinea pigs fed this soot develop steatosis and smooth endoplasmic reticulum (SER) proliferation as major hepatocyte alterations. The proliferated SER is associated with cytoplasmic vacuoles and laminated concentric membrane arrays (CMAs) usually associated with lipid. High-voltage electron microscopy examination of serial 0.25 micron sections revealed an occasional vacuole communicating directly with either a sinusoid or bile canaliculus. This channel provided a pathway for the ejection of membrane sheets and condensed fragments which shed from the luminal surface of the vacuoles. In addition, membrane sheets from the CMAs and proliferated SER were also ejected into the vacuoles. This resulted in continuity from the hepatocyte cytoplasm to the sinusoids and bile canaliculi via the vacuoles. Membrane sheets were also shed directly from the luminal surface of the bile canaliculi. Numerous membrane sheets and condensed fragments were found in the sinusoids, bile canaliculi and ducts. These morphologic observations elaborate a mechanism of direct and indirect membrane ejection from the hepatocyte into the blood and bile spaces and may explain the origin of reported elevated serum bilirubin and cholesterol levels. Since these PCDDs and PCDFs are excreted primarily via the bile, this ejection mechanism may be important in the detoxification process.

Animals↗
PubMed1984

Liver morphology in guinea pigs fed pyrolysis products of a polychlorinated biphenyl transformer fluid continuously for 90 days.

After a fire involving a transformer, the State Office Building in Binghamton, New York, was contaminated with soot containing polychlorinated biphenyls, biphenylenes, naphthalenes, dioxins, and dibenzofurans. The toxicity of the soot and its effect on liver morphology after prolonged (subchronic) exposure were determined for both sexes of Hartley guinea pigs, which were fed soot continuously for 90 days. By light microscopy the observed alterations of the liver were predominantly centrilobular; they included hepatocyte hypertrophy, steatosis, increased glycogen and iron, focal necrosis, and bile duct proliferation with fibrosis. Cytoplasmic vacuoles and acidophilic hyalin-like bodies were observed. Electron microscopy of hepatocytes showed proliferated smooth endoplasmic reticulum (SER), cytoplasmic vacuoles, concentric membrane arrays (CMAs), glycogen bodies, and microdroplets of fat, often without limiting membranes. The vacuoles frequently contained membrane fragments and had a halo-like periphery composed of proliferated membranes. Cell debris, membrane fragments, and small CMAs were observed in the sinusoids. Membrane fragments were also observed in the bile canaliculi and bile ducts. Intoxicated bile duct cells contained more cytoplasmic myelin whorls and altered mitochondria. In contrast to the previously reported study of a single dose, these liver alterations showed a strong dose dependence, emphasizing the importance of time and method of administration. The cytoplasmic vacuoles, which were not pronounced in the previous study, are here a prominent alteration, probably originating from outpouchings of canaliculi and sinusoidal membranes. A hypothesis for the mechanism of hepatocyte detoxification based on the proliferated SER and ejection of membrane fragments is proposed.

Animals↗
PubMed1984

Sarcomas of soft tissues after Vietnam service.

Vietnam service and military service experiences of 281 men with sarcomas of soft tissues were compared in this epidemiologic study to a control group of men derived from driver's license files and matched on 5-year period of birth and ZIP code of residence. No direct association was found for service in Vietnam (odds ratio, 0.53; confidence limits, 0.21-1.31) or for any military service (odds ratio, 0.53; confidence limits, 0.37-0.76). A multivariate matched logistic regression analysis showed similar results for Vietnam service while controlling for military service. Results also were similar when the 130 cases who had died were compared to a second control group derived from death certificates. Finally, no significant associations were found for "Agent Orange" or other variables that might be related to herbicide exposure.

Adult↗
PubMed1983

Liver morphology in guinea pigs administered either pyrolysis products of a polychlorinated biphenyl transformer fluid or 2,3,7,8-tetrachlorodibenzo-p-dioxin.

A transformer cooled and insulated with a mixture of 65% Aroclor 1254 and 35% chlorinated benzenes located in the Binghamton State Office Building in Binghamton, New York, was involved in a fire, which produced soot containing polychlorinated biphenyls, biphenylenes, dioxins, and dibenzofurans. A single dose of either soot or 2,3,7,8-tetrachlorodibenzo-p-dioxin in aqueous methyl cellulose was administered by gavage to Hartley guinea pigs of both sexes. The liver tissue was examined 42 days after administration. By light microscopy hypertrophy of hepatocytes, steatosis, focal necrosis, and cytoplasmic hyalin-like bodies were observed as a result of both treatments. Bile duct proliferation (adenofibrosis) was observed only in the guinea pig groups administered soot. These animals also showed proliferation of the smooth endoplasmic reticulum, concentric membrane arrays (CMA), mitochondrial alterations, decreased rough endoplasmic reticulum, and autophagolysosomes by electron microscopy. The CMAs, which corresponded to the hyalin-like bodies, surrounded lipid droplets and cytoplasmic matrix containing mitochondria and degenerating organelles.

Animals↗