Biomedical subjects

S Griffey

Publications and source records attributed to S Griffey.

11 recordsLinked to original sources

PubMed2001

Pathologic changes in grossly normal menisci in dogs with rupture of the cranial cruciate ligament.

OBJECTIVE: To determine whether histopathologic changes are detectable in grossly normal medial menisci from dogs with rupture of the cranial cruciate ligament (CCL). DESIGN: Case series. SAMPLE POPULATION: 40 medial menisci from dogs with rupture of the CCL and 20 medial menisci from control dogs without stifle joint disease. PROCEDURE: Data evaluated included age, duration of clinical signs, and whether rupture of the CCL was complete or incomplete. Three groups (n = 20/group) were also compared on the basis of 5 histologic criteria; group-1 menisci appeared grossly normal and were obtained from dogs with naturally occurring rupture of the CCL, group-2 menisci were grossly abnormal and were also obtained from dogs with naturally occurring CCL ruptures, and group-3 menisci were collected at postmortem from dogs without stifle joint disease that were of similar age and weight as dogs in groups 1 and 2. RESULTS: Group-2 menisci were significantly different from group-1 and -3 menisci in all histologic criteria. Group-1 menisci were significantly different from control menisci in only 1 of the 5 histologic criteria (cartilage differentiation). Dogs that were > or =3 years old had significantly more surface cellularity than did dogs that were < 3 years old. A significant difference was not detected between groups 1 and 2 with regard to completeness of rupture. CONCLUSIONS AND CLINICAL RELEVANCE: Histologic changes in meniscal cartilage correlate with gross appearance of the cartilage at time of surgery for rupture of the CCL. On the basis of minimal histologic changes, routine removal of grossly normal menisci does not appear to be warranted.

Age Factors↗

PubMed2001

Particulate dermal matrix as an injectable soft tissue replacement material.

Products currently used as injectable soft tissue replacement materials in the dermatologic, plastic and reconstructive, and urological fields exhibit several shortfalls including reactivity, migration, rapid degradation, and necessity of a donor site. This study examines the feasibility of providing a particulate acellular human dermal matrix for injection as a soft tissue replacement material that addresses many of these issues. Animal feasibility studies tested differences in implant performance related to processing techniques, matrix concentration, and volume of the collagen matrix to be injected. Results demonstrated that processing techniques that involve shearing and tearing of the dermal collagen matrix resulted in frayed and damaged collagen bundles and led to rapid resorption or loss of the implant, when injected subcutaneously in a rat model. Processing the collagen matrix in liquid nitrogen resulted in less damage to the collagen matrix and exhibited longer persistence, when compared to the damaged collagen matrix. This particulate matrix also exhibits rapid repopulation by host cells that should enhance revascularization and remodeling. The particulate nature of this processed dermal matrix allows for easy delivery of concentrations up to 330 mg/mL, which exceeds that of other currently used products. This increased concentration should allow for decreased need of "overcorrection" and repeated injections.

Animals↗

PubMed2001

Reduced expression of cyclin-dependent kinase inhibitor p27Kip1 in feline lymphoma.

Expression of p27Kip1 was identified in feline lymphoid tissues by immunohistochemistry. In normal lymphoid tissues, p27Kip1 was detected as a distinct nuclear stain in lymphocytes of the follicular mantle zone and interfollicular small lymphocytes, whereas activated lymphoblasts in the germinal center were negative. Lymphoid hyperplasia was similarly immunolabeled but with an expanded mantle zone and marginal zone of p27Kip1-reactive lymphocytes. Both T- and B-cell lymphomas lacked p27Kip1 immunolabel and were determined to be proliferative based on immunohistochemical detection of the Ki-67 antigen. Scattered p27Kip1-immunolabeled lymphocytes were detected throughout the lamina propria of most specimens characterized as lymphoplasmacytic enteritis. The results of this study suggest that the antiproliferative effect of the cell cycle regulator p27Kip1 is abrogated in feline lymphoma, presumably allowing cells to bypass the G1-S checkpoint of the cell cycle.

Animals↗

PubMed2000

Prognostic factors and patterns of treatment failure in dogs with unresectable differentiated thyroid carcinomas treated with megavoltage irradiation.

OBJECTIVE: To determine quality and duration of progression-free survival (PFS) time in dogs with unresectable thyroid carcinomas treated with definitive megavoltage irradiation and analyze prognostic factors of PFS and patterns of failure (local recurrence vs metastasis). DESIGN: Prospective clinical trial. ANIMALS: 25 dogs with locally advanced thyroid carcinomas and no evidence of metastasis. PROCEDURE: Dogs were treated with 48 Gy during 4 weeks on an alternate-day schedule of 4 Gy/fraction. RESULTS: Irradiation was safe and effective for treatment of large unresectable thyroid carcinomas. Progression-free survival rates were 80% at 1 year and 72% at 3 years. Time to maximum tumor size reduction ranged from 8 to 22 months. Factors affecting PFS were not found. Twenty-eight percent (7/25) of dogs developed metastasis. Dogs with bilateral tumors had 16 times the risk of developing metastases, compared with dogs with a single tumor. Dogs with no evidence of tumor progression had 15 times less risk of developing metastases. Radiation-induced hypothyroidism was suspected in 2 dogs 13 and 29 months after irradiation. CONCLUSIONS AND CLINICAL RELEVANCE: Irradiation is effective for local control of thyroid tumors, despite their slow regression rate. Results provided evidence that local tumor control affects metastatic outcome in dogs with thyroid carcinomas and is a strong basis for the development of new approaches that include irradiation in the management of dogs with advanced thyroid carcinomas. Improvements in local tumor control alone may be insufficient to improve survival times because of the high risk of metastatic spread before an initial diagnosis is made, which warrants initiation of early systemic treatment.

Animals↗

PubMed1997

Analysis of prognostic factors and patterns of failure in dogs with periodontal tumors treated with megavoltage irradiation.

OBJECTIVE: To determine quality and duration of progression-free survival (PFS) time in dogs with periodontal tumors after definitive megavoltage irradiation and to analyze prognostic factors for PFS time and patterns of treatment failure. DESIGN: Prospective clinical trial. ANIMALS: 47 dogs with acanthomatous, fibromatous, or ossifying epulis. PROCEDURE: Dogs were treated with 48 Gy over 4 weeks on an alternate-day schedule of 4 Gy/fraction. Multivariate analysis was done by use of Cox's proportional hazards regression model to determine prognostic factors for PFS time. RESULTS: The only independent prognostic factor for PFS time was tumor T stage. Pattern of local tumor recurrence (marginal vs infield regrowth) was independent of clinical stage, tumor location, and site. In 4% of the dogs, severe acute radiation reactions in the final week of treatment resulted in treatment discontinuation. In 6.4% of the dogs, chronic radiation reactions included bone necrosis. CLINICAL IMPLICATIONS: Irradiation was a safe and effective treatment of small (T1 and T2 stage) periodontal tumors. The usefulness of the radiation protocol in this study is limited in dogs with large (T3) tumors, particularly those located in the caudal half of the oral cavity, because of poor results and high risk of acute radiation toxicoses.

Animals↗

PubMed1997

Dietary modulation of methotrexate-induced enteritis in cats.

OBJECTIVE: To determine effects of purified and dry expanded (complex) diets on intestinal structure and function in healthy cats and in a feline model of methotrexate-induced enteritis. ANIMALS: 19 adult specific-pathogen-free cats. PROCEDURE: Cats were randomized in groups to receive a purified diet intragastrically or a complex diet orally to meet their daily metabolizable energy requirements. After 21 days, cats received either methotrexate (MTX; 10 mg/kg of body weight, i.v., n = 12) or saline solution i.v. (n = 7), and were anesthetized 72 hours later. Celiotomy was performed for aseptic removal of mesenteric lymph nodes, full-thickness biopsy of the gastrointestinal tract, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine. RESULTS: MTX was associated with severe enterotoxicosis in cats receiving the purified diet, as manifested by diarrhea (4 of 6 cats) and vomiting (2 of 6 cats). One cat receiving the complex diet developed mild diarrhea, and none of these cats vomited. The purified diet was associated with marked villus blunting in the proximal and distal portions of the duodenum and increased bacterial translocation (3 of 6 cats), whereas none of the cats in the complex diet group developed bacterial translocation after MTX administration. For the cats given saline solution, bacterial translocation occurred in 1 of 4 cats receiving the complex diet versus 2 of 3 cats receiving the purified diet. CONCLUSIONS: Feeding of a complex diet containing intact protein as the nitrogen source abrogated the proximal small intestinal atrophy and bacterial translocation associated with feeding an amino acid-based purified diet. CLINICAL RELEVANCE: Use of purified diets containing free amino acids as the only nitrogen source cannot be endorsed in human and animal cancer patients receiving systemic chemotherapy.

Animal Feed↗

PubMed1995

A computer-controlled, continuously circulating, hot irrigating system for endometrial ablation.

OBJECTIVE: This study evaluated the efficacy of a computer-controlled thermal catheter system to ablate the endometrium by use of 5 to 15 ml of hot saline solution. STUDY DESIGN: Five in vivo sheep uteri and 32 freshly excised human uteri were studied by inserting a self-contained heater catheter equipped with thermocouples and circulating hot saline solution for 15 minutes within the uteri at various temperature settings ranging from 60 degrees C to 80 degrees C. The uteri were grossly examined and microscopically evaluated by hematoxylin and eosin and reduced nicotinamide adenine dinucleotide-diaphorase stains for degree of acute destruction, depth of thermal injury, and predicted viability. RESULTS: All 80 degrees C sheep treatments resulted in complete loss of viability at mucosal, submucosal, and myometrial levels. In human uteri temperatures > or = 80 degrees C produced grossly recognizable thermal damage to the endometrium. Full-thickness irreversible damage was seen in the endometrium. Loss of viability was also demonstrated 1 to 3 mm deep in the superficial myometrium. Intrauterine pressure was demonstrated to range from 20 to 40 mm Hg, with a mean of 26 mm Hg. No leakage of fluid from the oviducts was observed. CONCLUSION: The data presented here demonstrate that a simple technique coupled with a sophisticated monitoring control system could successfully ablate the endometrium without the vagaries associated with individual operator skill levels.

Animals↗

PubMed1995

Microvascular transplantation of cryopreserved knee joints.

Successful transplantation of cryopreserved complex tissues has not yet been reported. We wanted to test whether microvascular transplantation of cryopreserved knee joints can be achieved in rats. Twenty-five knee joints were cryopreserved and then microsurgically transplanted to the groin of inbred recipient animals. Ten fresh knee joints were transplanted as controls. One week after transplantation, the transplants were evaluated in situ for pedicle patency and tissue perfusion and then harvested for histology. In all surviving rats (n = 21), the cryopreserved knee joints were well perfused immediately after transplantation. At harvest, 14 knee joints appeared viable with a patent pedicle, whereas 6 were questionably viable and demonstrated arterial thrombosis. Histologically, the viable joints revealed an intact bone and cartilage matrix; however, the number of viable chondrocytes and osteocytes was reduced. Additionally, endothelial cell plugs in some areas of the capillary bed led to scattered microinfarctions despite a patent vascular pedicle. The nonperfused transplants showed infarction. In conclusion, we have demonstrated successful microvascular transplantation of cryopreserved knee joints with reduced short-term viability. Long-term studies must determine whether full recovery occurs.

Animals↗

PubMed1994

In situ analysis of cellular proliferation in canine, feline and equine tumors by immunohistochemistry: a comparison of bromodeoxyuridine, proliferating cell nuclear antigen, and interchromatin-associated antigen immunostaining techniques.

Cell proliferation in canine, feline, and equine tumors was evaluated using immunohistochemical detection of in vitro 5-bromodeoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen (PCNA), and interchromatin-associated antigen (p105). Ten tumors in each species were analyzed. The tumor proliferative fraction (PF) was defined as the percentage of labeled nuclei for 5,000 tumor nuclei counted. Immunoreactivity was observed with all techniques in all species. A good correlation was observed between the proliferative fractions measured with the BrdU (PFBrdU) and PCNA (PFPCNA) techniques (rs = 0.523, P = 0.0026). There was no correlation between the PFs measured with the BrdU (PFBrdU) and p105 (PFP105) techniques. Using the median values obtained from the different approaches as cutoff points to define slowly and rapidly proliferating tumors, there was an 80% agreement (P = 0.009) between PFBrdU and PFPCNA and no agreement between PFBrdU and PFP105. The results of this study indicate that both BrdU and PCNA labeling methods can be used reliably for identifying proliferating cells in animal tumors. In addition, PCNA could be used to replace the BrdU method to assess tumor proliferative fraction because it does not require pretreatment of tissues.

Animals↗

PubMedDate not supplied

Acellular human dermis promotes cultured keratinocyte engraftment.

In full-thickness skin injury, loss of dermis may result in compromised wound repair, including contracture, hypertrophic scarring, and wound breakdown. This report examines the effect of an acellular dermal matrix on in vivo skin repair. Human keratinocytes cultured onto a synthetic hydrophilic dressing were applied with (N = 9) and without (N = 11) an acellular dermal matrix to full-thickness skin defects on athymic mice. Host cells progressively repopulated the acellular dermal component of the grafts. All animals with dermal matrix revealed fully differentiated epidermis by postoperative day 21. Human keratinocytes persisted in all animals grafted with dermal matrix, compared to only 63.6% of those animals without a dermal component. Planimetric analysis revealed significantly reduced wound contraction (p = 0.016) in animals receiving the dermal matrix. Histologic, immunohistochemical, and electron microscopic analyses also were performed. These studies suggest that an acellular dermal matrix can effectively direct regeneration of normal skin morphology.

Animals↗

PubMedDate not supplied

Noninvasive evaluation of the aorto-iliac segment.

Eighty-five patients (169 limbs) were studied in the Noninvasive Vascular Laboratory at the Lahey Clinic as part of a preoperative evaluation for arterial insufficiency. Segmental Doppler systolic pressures and peak velocity waveform analysis using a directional Doppler were performed on all patients. Normal velocity waveforms demonstrated forward flow during systole, reverse flow during the first half of diastole and a return to forward flow again during the latter part of diastole (triphasic flow). Significantly abnormal waveforms did not demonstrate reverse flow during the first half of diastole (monophasic flow). A significantly abnormal angiogram showed a greater than 50% stenosis in the aorto-iliac segment. A comparison of Doppler velocity waveforms with arteriograms showed a 96% correlation. Most errors in our study were technical; related to the assumption that the inguinal skin crease marked the location of the inguinal ligament and the origin of the common femoral artery. In these instances, the superficial femoral artery not the common femoral artery was sampled. Common sources of false positive studies were severe outflow obstruction or recent surgery to the common femoral artery, both showing a loss of laminar flow and a monophasic waveform. Patients who demonstrate reverse flow in the common femoral artery by directional Doppler examination had adequate inflow to support a femoral-popliteal or femoral-femoral by pass graft. Patients with monophasic flow had either inadequate aorto-iliac segments, recent surgery to the common femoral artery or severe outflow obstruction. Supportive data will be presented in detail.

Angiography↗