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Biomedical subjects

D E Sweet

Publications and source records attributed to D E Sweet.

At least 19 recordsLinked to original sources
PubMed1992

Asymptomatic HIV infection. A primary care disease.

Asymptomatic human immunodeficiency virus infection is a disease entering the primary care arena more and more frequently. Patients may be monitored in this setting until complications and clinical deterioration develop (typically after several years). As the disease progresses, referral to consultants who specialize in AIDS may be appropriate. However, many patients do not live near a major healthcare center and do not have the financial, physical, or emotional capability to travel to one as they become sicker. In these cases, primary care physicians, with the aid of a personally chosen network of specialized consultants, should offer care as the disease progresses to its terminal stage.

AIDS-Related Opportunistic Infections↗
PubMed1992

Cortical osteofibrous dysplasia of long bone and its relationship to adamantinoma. A clinicopathologic study of 30 cases.

Thirty cases of cortical osteofibrous dysplasia (COFD) were studied in an attempt at defining the relationship of COFD to adamantinoma. The patients ranged in age from newborn to 39 years (mean 13.4 years). The male:female ratio was 1:1. Presenting symptoms were most often pain or a mass. The tibia was involved in all 30 patients; in addition, the ipsilateral fibula was involved in five patients (17%). The histologic appearance of the lesions was dominated by the combination of woven bone trabeculae with prominent osteoblastic rimming and a loose, slightly myxoid stroma (less heavily collagenized in most instances than usually encountered in intramedullary fibrous dysplasia). Results of immunohistochemical study showed isolated cytokeratin-positive cells in the stroma of 28 of the lesions (93%). However, hyperchromatic epithelial islands characteristic of adamantinoma were not found in any of the 30 cases. A control population of 50 fibro-osseous lesions (intramedullary fibrous dysplasia, sclerosing fibroxanthoma, and cranial ossifying fibroma) was studied immunohistochemically; in none of these control cases were cytokeratin-positive cells found. Follow-up data were obtained in 17 cases (57%); the period ranged from 1 to 16 years (mean 6.05 years). Certain overlapping clinical features (including the location of the vast majority of the lesions in the tibia and, less often, the fibula) and the morphologic similarities of many areas of COFD and adamantinoma (particularly the shared presence of cytokeratin-positive cells) suggest a more than coincidental association between COFD and a adamantinoma. However, to date none of the 30 cases of COFD evaluated in this study has developed an adamantinoma.

Adolescent↗
PubMed1992

Giant cell tumor in skeletally immature patients.

The radiographs and clinical and surgical histories of 50 skeletally immature patients with histologically verified giant cell tumor (GCT) of the long and short tubular bones were retrospectively studied to determine the prevalence, location within bone (eg, epiphysis, metaphysis), skeletal distribution, radiographic appearance, and pathogenesis of GCTs. Skeletal immaturity was determined radiographically by the presence of open epiphyses. Patients were selected from a group of 876 patients who were seen in consultation with documented GCT of the tubular bones. Approximately 5.7% of all GCTs occurred in the skeletally immature (this rate must be viewed with caution due to the selection bias inherent in any referral population). The lesions almost invariably involved the metaphysis. The tibia was the most commonly affected site, representing approximately 26% of cases. All were geographic lytic lesions, with margins ranging from sclerotic to ill defined. An expanded (widened), remodeled bone contour was frequently encountered. Approximately 56% of lesions were solid or solid with cystic change; the remaining 44% were predominantly cystic.

Adolescent↗
PubMed1992

Parosteal lipomas: a new perspective.

Parosteal lipomas, benign adipose tissue tumors situated directly on bone cortex, are unusual neoplasms that appear to emerge from multidirectional mesenchymal "modulation" within the periosteum. These tumors have been described as "periosteal lipomas", "chondrolipomas of soft tissue" and "lipomas of nerves" but they are most commonly believed to originate from the periosteum. Although over 100 of such tumors have been described in the literature, they have not been the subject of a comprehensive review, nor their potential for chondroid modulation and enchondral ossification emphasized. A review of 14 parosteal lipomas from the Bone Tumor Registry, Armed Forces Institute of Pathology, indicates these tumors are frequently associated with chondroid and/or osseous modulation, which permits subclassification into 4 distinct variants. Each of the 4 subtypes (I: No Ossification; II: Pedunculated Exostosis; III: Sessile Exostosis; IV: Patchy Chondro-Osseous Modulation) is illustrated to demonstrate the morphologic basis for radiologic/pathologic correlation and subclassification. A brief overview of the literature and pathogenesis of this unusual lesion is presented and discussed.

Aged↗
PubMed1991

A histomorphologic and immunohistochemical study of chordoma in twenty ferrets (Mustela putorius furo).

The histomorphologic and immunohistochemical features of chordoma in 20 ferrets were evaluated. The mean age was 3.4 years, and, in the cases for which sex was known, females (n = 10) outnumbered males (n = 5) two to one. All 20 tumors occurred on the tip of the tail. Nineteen of 20 tumors (95%) were composed of three tissue components, often arranged concentrically with lobules of physaliferous cells at the periphery, trabecular bone in the center, and cartilage in between. The bone often contained marrow and hematopoietic cells. One tumor lacked chondromatous or osseous tissue. Immunohistochemical results were consistent with previous studies of chordoma. All 20 tumors (100%) were positive for keratin and vimentin intermediate filaments; 15 (75%) were positive for S-100 protein; and 17 (85%) were positive for neuron specific enolase. This neoplasm shares morphologic and immunohistochemical features with "classic," as well as chondroid chordoma, of human beings, making it a potential animal model.

Animals↗
PubMed1991

John Caffey Award paper. Avascular necrosis: early MR imaging and histologic findings in a canine model.

To examine the early MR and histologic changes of avascular necrosis, we surgically devascularized the distal femur of adult beagle dogs and performed short TR/short TE MR imaging and histologic examinations. MR showed increasing areas of low signal, and histologic examination showed changes of fat necrosis, inflammatory infiltrate, and fibrocytic and bony repair. These processes were divided into four stages. Stage 1 is seen in the first days after surgery and consists of homogeneous high signal on MR and only subtle histologic changes of early fat necrosis. Stage 2, seen by 7 days after surgery, shows linear low-signal areas within the high-signal marrow on MR and fat necrosis and an inflammatory infiltrate on histologic sections. Stage 3, seen by 16 days after surgery, shows patchy low signal occupying more of the marrow on MR with a fibrocytic infiltrate on histologic sections. Stage 4, seen by 23 days after surgery, shows a more homogeneous low and intermediate signal on MR and histologic findings of more organized fibrocytes and the onset of new bone formation. Using this model, we have proved that MR imaging can show marrow changes as soon as 1 week after the onset of avascular necrosis. Whereas MR imaging showed a progression of increasing areas of low signal, the histologic findings seen during this time were diverse, including inflammatory infiltration (a previously unreported finding), fat necrosis, and fibrocytic and osseous repair.

Animals↗
PubMed1991

Well-differentiated extraskeletal osteosarcoma. A soft-tissue homologue of parosteal osteosarcoma.

We describe a unique case of a low-grade extraskeletal osteosarcoma revealing both histologic and radiologic features reminiscent of parosteal osteosarcoma. The tumor, which had been present for 10 years, occurred in the left axilla of a 74-year-old black woman. To date, all the published cases of extraskeletal osteosarcoma have been high-grade neoplasms; to our knowledge, this is the first reported case of a low-grade extraskeletal osteosarcoma.

Aged↗
PubMed1990

Osteoid osteoma of the elbow. A review of six cases.

Six cases of osteoid osteoma of the elbow were reviewed to determine the spectrum of clinical, pathologic and radiologic findings. Since osteoid osteoma of the elbow may masquerade as a nonspecific synovitis, the diagnosis is challenging and frequently delayed. The histology is, however, indistinguishable from that of osteoid osteoma occurring in typical locations. The radiologic features of osteoid osteoma of the elbow include the following triad: (a) osteosclerosis, usually a dominant feature at initial imaging and typically enveloping the nidus; (b) joint effusion; and (c) periosteal reaction that can involve both the bone in which the osteoid osteoma arises and adjacent bones. Awareness of these features will facilitate correct diagnosis, thereby facilitating timely and appropriate treatment.

Adult↗
PubMed1990

Osteosarcomatosis.

A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized.

Adolescent↗
PubMed1990

Biphasic response of rat tibial growth to thyroxine administration.

To evaluate the dose-response relationship between thyroxine and tibial growth, 60 male rats age 21 days were rendered hypothyroid by administration of methimazole in the drinking water. Twenty-one days later, the hypothyroid rats were randomly divided into 5 groups which received 0, 2, 8, 32, or 64 micrograms.kg-1.day-1 of T4 im for 21 days. All animals were sacrificed at age 64 days. Rat tibia were removed for measurement of epiphyseal growth plate width and longitudinal growth rate. Serum T4 and IGF-I levels were determined by RIA. Methimazole therapy significantly decreased serum T4, IGF-I, epiphyseal growth plate width, and longitudinal growth rate compared to controls. Epiphyseal growth plate width gradually increased when T4 was administered at doses from 2 to 32 micrograms.kg-1.day-1 (271 +/- 14, 311 +/- 15 and 324 +/- 11 microns), and subsequently decreased when T4 was given at a dose of 64 micrograms.kg-1.day-1 (267 +/- 8 microns). A similar profile was observed for longitudinal growth rate and IGF-I. We conclude that rat tibial growth has a biphasic response to exogenous T4 administration, and that the effects of T4 on tibial growth may be mediated through IGF-I secretion.

Animals↗
PubMed1989

Radiology as gross pathology in evaluating chondroid lesions.

The study of large ("whole mount") histologic sections underscores the complexity of bone lesions and explains the great potential for misdiagnosis when a limited biopsy sample is assumed to be totally representative. Diagnostic pitfalls can generally be avoided by insisting on the opportunity for clinical-radiologic-pathologic correlation ("triangulation") before a final diagnosis is made. Essential to the method of triangulation is equal attention to the three lines of evidence. The ability to render reliable, clinically relevant, and individually pertinent consultations (as opposed to purely histologic opinions) derives from pursuing questions until all lines of evidence point ("triangulate") to the same answer. This is especially true in the realm of cartilage tumors where the limitations of histopathology are widely acknowledged. In this review, the use of radiographic data will be explored in general terms and in the special context of chondroid lesions.

Humans↗
PubMed1989

Direct administration of testosterone increases rat tibial epiphyseal growth plate width.

Local injection of hormones into the tibial epiphyseal growth plate offers a possible model to answer whether sex steroids can affect bone growth directly. To answer this question, we injected different doses of testosterone enanthate (4, 40, 120 and 400 micrograms/100 g of rat weight) once into the tibial epiphyseal growth plate of castrated 35-day-old male rats. The contralateral tibia was injected with sesame oil and served as control. All animals were sacrificed at age 42 days. Tibias were removed for measurement of epiphyseal growth plate width and blood was collected for measurement of serum IGF-I and testosterone. The lower doses of testosterone enanthate (4, 40 and 120 micrograms/100 g) did not produce any significant change in epiphyseal growth plate width. Testosterone at the largest dose tested (400 micrograms/100 g) increased epiphyseal growth plate width by about 15% compared to control (p less than 0.01). At this dose, serum testosterone was not increased, suggesting that the effect on epiphyseal growth plate width was not due to higher systemic testosterone concentrations. No differences in IGF-I levels were observed among the groups. We conclude that direct administration of testosterone enanthate at a dose of 400 micrograms/100 g into the rat tibial epiphyseal growth plate can increase epiphyseal growth plate width.

Animals↗
PubMed1989

Comparison of heparin and 0.9% sodium chloride injection in the maintenance of indwelling intermittent i.v. devices.

Heparin sodium 10 units/mL was compared with 0.9% sodium chloride injection as a flush solution for indwelling intermittent i.v. devices, or i.v. locks (IVLs), in a prospective, randomized, double-blind study. The heparin and 0.9% sodium chloride injections were prepared in the pharmacy using aseptic technique. Most of the IVLs were inserted by an i.v. therapy team member. Each patient's IVL site was evaluated for phlebitis and patency by one of three study nurses, and when a catheter was removed, its contents were flushed so that clots or fibrin strands could be detected. Nurses also collected information regarding disease states, surgical procedures, medications administered, and how long each site lasted. A total of 173 sites were studied in 76 patients in the heparin group, and 131 sites were studied in 71 patients in the sodium chloride group. The groups were well matched, except that the sodium chloride group received more vancomycin and dextrose-containing i.v. solutions, while the heparin group received more penicillins. There was no significant difference in the incidence of phlebitis or lost patency between the groups. When locks through which vancomycin, penicillins, and dextrose-containing i.v. solutions were administered were excluded, there was still no significant difference between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Multiple sclerosis presenting as an intramedullary cervical cord tumor.

We report a case of a 21-year-old white woman with a three-week history of rapidly progressive paresis and paresthesias of her extremities presenting as an intramedullary cervical cord lesion. Computer-assisted tomography and magnetic resonance imaging demonstrated a normal brain with a cervical cord enlargement suggestive of a primary spinal cord tumor. Her neurological deficits progressed despite dexamethasone; hence, laminectomy was performed with open biopsy of the cord lesion. The pathological specimens were sent to the Mayo Clinic and Kansas University for cell-type determination, due to their bizarre morphology. Both institutions concluded the biopsy specimens were demyelinated axonal plaques consistent with multiple sclerosis. This case illustrates that demyelinating disease can mimic spinal cord tumor, even with MRI scanning. Multiple sclerosis is a chronic demyelinating disease of the central nervous system. The clinical diagnosis requires documentation of lesions occurring on more than one occasion and at more than one site in the central nervous system. To improve the accuracy of the diagnosis of multiple sclerosis, spinal fluid analysis, visual and auditory evoked responses and radiologic imaging have been proposed. We report a patient with multiple sclerosis who presented with symptoms and physical findings suggesting a primary cervical cord tumor. Localized enlargement of the cervical cord was documented on magnetic resonance imaging. This is the first reported description of histopathologically confirmed spinal cord demyelination presenting as an intramedullary cervical cord tumor.

Adult↗