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R Apel

Publications and source records attributed to R Apel.

13 recordsLinked to original sources
PubMed1997

A semi-solid drug delivery system for epidermal growth factor in corneal epithelial wound healing.

PURPOSE: To examine the effects of EGF, delivered from a semi-solid drug delivery system, on corneal epithelial wound healing following anterior keratectomy wound creation in the eyes of New Zealand white rabbits. METHODS: A semi-solid drug delivery system based on a Carbopol gel was developed. Following creation of a 7.5 mm circular anterior keratectomy wound, 50 microL of either a placebo gel or an EGF-containing gel, was instilled in the inferior fornix. The gel remained in the eye for 8 hours, at which time it was removed. Anaesthesia was maintained for the entire 8-hour period. Wound healing was evaluated by quantitative morphometry. We evaluated 0.04, 0.1, 0.2, 0.4, and 1% EGF concentrations in the gel. Tear EGF concentrations and histology of the healing corneas were also examined. RESULTS: The enhancement factor (ratio of the healing rate with the EGF gel and control gel) was 1.13 +/- 0.12, 1.40 +/- 0.14, 1.29 +/- 0.12, 1.80 +/- 0.22, and 1.09 +/- 0.12 for the gels containing 0.04, 0.1, 0.2, 0.4, and 1% EGF by mass, respectively. The increases in the rate of wound healing were significant with the 0.1, 0.2 and 0.4% gel formulations. Histologically, the 0.4% gels resulted in cellular hyperplasia after 5 days of healing. Differences between the placebo gel-treated and EGF-containing gel-treated eyes were evaluated at both 2 and 5 days. The concentration of EGF in the tears during the treatment period was approximately constant for both the 1% and 0.04% gels. The average tear concentration during the instillation period was 2.87 +/- 0.36 micrograms/mL and 200.61 ng/mL +/- 116.10 for the 1% and 0.04% gels respectively. CONCLUSIONS: Treatment with EGF in a Carbopol gel carrier for a period of 8 hours results in significant wound healing enhancement (p < 0.05). The optimum EGF loading in the gel was determined to be 0.4%. A slow release gel may be an effective way to deliver EGF to the corneal surface.

Animals↗
PubMed1994

Prospective evaluation of early morphological changes in pelvic ileal pouches.

BACKGROUND/AIMS: Little is known about the evolution of morphological changes in pelvic ileal-pouch mucosa. This study evaluates prospectively the sequence of early morphological, histochemical, and phenotypic features in pouch mucosal biopsy specimens. METHODS: Twenty-two patients with pelvic ileal pouches constructed after total colectomy for chronic ulcerative colitis had biopsies performed at the time of ileostomy closure and after 6 weeks and 6 months of pouch function and were evaluated to assess the type and degree of inflammation, villus atrophy, Paneth's cell hyperplasia, mucin histochemical changes, the mucosal proliferative activity using the murine monoclonal antibody 1 (MIB-1), and the expression of the enzyme sucrase-isomaltase. RESULTS: Early changes (6 weeks) were characterized by neutrophilic and eosinophilic inflammation, mild villus atrophy, Paneth's cell hyperplasia, a partial transition to colonic mucin phenotype, and an increased MIB-1 proliferation index. These features remained relatively stable after 6 months, except for a greater degree of mononuclear infiltration, a progressive increase in the degree of eosinophilic inflammation and a new higher steady state level of crypt epithelial kinetics. Expression of sucrase-isomaltase remained stable. CONCLUSIONS: Pelvic ileal pouches develop inflammatory, phenotypic, and kinetic changes early in the course of function but have only a limited potential for colonic type metaplasia. The persistence of these changes is evidence in support of an adaptive response to a new luminal environment.

Adolescent↗
PubMed1993

Repair and reconstruction of the anterior cruciate ligament by the "Sandwich technique". A comparative microangiographic and histological study in the rabbit.

The effect of complete ensheathment of the repaired or reconstructed anterior cruciate ligament (ACL) in the infrapatellar fat pad was studied in a rabbit model. Four to 16 weeks after repair of a transected ACL or insertion of an autologous tendon graft these tissues were evaluated by histology and microangiography. Following ACL repair a high incidence of ligament atrophy was evident in both the ensheathed (43%) and the non-ensheathed control (54%) group. In functional ligaments a similar sequence of remodelling events was evident in both the ensheathed and the non-ensheathed group: infiltration of the transected area by mesenchymal cells, maturation of these cells to fibroblasts, and increasing organization of newly formed collagen fibres. An initial hypervascular reaction was followed by a decrease in the number and an increase in the longitudinal orientation of blood vessels. Despite a similar sequence of remodelling events, however, this process was considerably accelerated in repaired ligaments ensheathed with infrapatellar fat pad compared with non-ensheathed controls. At 16 weeks only the ensheathed repaired ACL resembled the normal ACL morphologically, even though it was still hypercellular. The tendon autograft followed a similar course from an initially avascular and acellular tissue towards a structure similar to the normal ACL. In the ensheathed ligaments and tendon grafts vascular and cellular ingrowth as well as subsequent maturation were again accelerated. This effect may be attributable to improved revascularization and cell repopulation, as well as protection from synovial fluid by the surrounding fat pad.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1993

Hepatitis B virus infection in liver allografts.

Liver transplantation of hepatitis B surface antigen (HBsAg)-positive patients has been associated with high morbidity and mortality secondary to hepatitis B (HB) recurrence in the graft. Eight patients of the Queensland Liver Transplant Service were HBsAg positive pretransplant. Six acquired HB infection of the graft, one developed serological recurrence of HB before early death from sepsis, and one HB e antigen-negative patient permanently cleared the virus. HB-infected grafts showed early expression of viral antigen, acute hepatitis, fibrosing cholestatic hepatitis, chronic active hepatitis, cirrhosis, or minimal changes associated with a carrier state. Only in the latter case was HB mild and nonprogressive. Cases of fibrosing cholestatic hepatitis progressed rapidly to liver failure; they showed fibrosis and plates of ductular epithelium extending from portal tracts into lobules, cholestasis, ballooning of hepatocytes, and prominent hepatocyte expression of viral antigens. Perioperative HB immunoglobulin proved ineffective in preventing HB recurrence. One other patient became HBsAg positive for the first time after retransplantation; he developed severe acute hepatitis, then chronic active hepatitis. Our biopsy findings support the view that, in liver allografts, the HB virus may be directly cytopathic.

Acute Disease↗
PubMed1993

Continuous epidermal growth factor delivery in corneal epithelial wound healing.

PURPOSE: To investigate the effects of a single prolonged exposure to recombinant epidermal growth factor on the healing of anterior keratotomy wounds in New Zealand white rabbits. METHODS: After wounding, eyes were perfused for 1, 2, 4, and 8 hours with either epidermal growth factor solution at a concentration of 50 micrograms/ml or balanced saline solution using a Morgan therapeutic lens (Mortan Inc, Missoula MT) and a syringe pump. Furthermore, concentration response was evaluated by perfusing with epidermal growth factor solutions at concentrations of 5, 50, 100 and 500 micrograms/ml for 4 hours. Wound healing rates were determined by quantitative morphometry of the wound area. The ratio of healing rates of eyes perfused with epidermal growth factor and control eyes provided a measure of the effect of epidermal growth factor on wound healing, and was defined as the epidermal growth factor enhancement factor. RESULTS: The enhancement factor was found to be 1.04 +/- 0.08, 1.17 +/- 0.07, 1.43 +/- 0.09, and 1.59 +/- 0.07 for perfusion times of 1, 2, 4, and 8 hours, respectively. The concentration response enhancement factors were 0.99 +/- 0.08, 1.43 +/- 0.09, 1.21 +/- 0.09, and 0.95 +/- 0.07 for the 5, 50, 100, and 500 micrograms/ml 4-hour perfusions, respectively. CONCLUSION: The results indicated that continuous epidermal growth factor exposures of as few as 2 hours produced a significant increase in healing rates (P < 0.05); increasing the time of exposure further increases the rate of wound healing. Results from the concentration response experiments showed that the optimum epidermal growth factor concentration for enhancing epithelial wound healing is approximately 50 micrograms/ml.

Animals↗
PubMed1991

[Calcareous tendinitis--special forms of the upper extremities. Clinical aspects and differential diagnosis].

Calcifying tendinitis of the shoulder joint is a relatively common condition. Its pathogenesis is well documented in anatomical-pathological terms. The clinical observation of four unusual locations in the upper limb makes us to suspect the same pathological process as in the supraspinatus location. The clinical course of calcifying tendinitis in a typical location is discussed in detail.

Adult↗
PubMed1989

[Transient osteoporosis or femur head necrosis? Early diagnosis using MRT].

Transient osteoporosis of the hip is a syndrome that does not seem to be widely known; this is also true for its radiological appearance. It is often mistaken for avascular necrosis of the femoral head, metastatic or inflammatory disease. These differential diagnoses lead to more or less invasive procedures, although transient osteoporosis does not require more than immobilisation for complete remission. MRI was done in 38 patients with acute hip pain, 13 had femoral head necrosis and 8 transient osteoporosis. Follow-up studies via MRI in patients with transient osteoporosis revealed 3 stages (diffuse, focal, residual) during the clinical course of which stage II is similar to femoral head necrosis but always without the typical sclerotic rim.

Adolescent↗
PubMed1989

[Acute hip pain in the adult--assessment by magnetic resonance tomography].

Using the modern cross-sectional imaging technique of MRI, significant improvement has been achieved in the early diagnosis of acute hip diseases, such as avascular femoral head necrosis, transient osteoporosis, coxitis, and tumors, the demarcation of which can be seen by MRI. Studies with MRI in patients with transient osteoporosis have revealed three stages during the clinical course. The focal stage is similar to femoral head necrosis, but always without the typical sclerotic rim. To obtain complete remission, transient osteoporosis only requires immobilization. There are difficulties in diagnosing infected and neoplastic processes.

Acute Disease↗
PubMed1986

[Alloplastic replacement of the anterior cruciate ligament by a polytetrafluoroethylene ligament. Animal experiment study].

4 sheep knees received an implant of polytetrafluorethylene. 18 month after implantation the clinical and histological investigation showed two cases of anterior instability and rupture of parts of the prosthesis. We sw severe degenerative lesions intraarticular with chronic inflammation characterized by the proliferation of immature fibroblasts, the accumulation of macrophages and the formation of multinucleated giant cells. The transfer of our results to the human knee is discussed.

Animals↗
PubMed1985

Nuclear polymorphism in osteosarcomas as a prognostic factor for the effect of chemotherapy. A quantitative study.

A current strategy for osteosarcoma treatment is neo-adjuvant chemotherapy prior to the resection of the tumour. It appears that some tumours respond very well to the cytostatic therapy, while others show little or no effect. It is desirable to be able predict the response of the tumour before starting chemotherapy. 16 biopsy specimens from patients with osteosarcoma who had been treated according to the protocol of the study COSS-80 and COSS-82 were examined. 100 tumour cells from each biopsy have been measured by an electronic interactive image analysis system (IBAS II; Kontron/ZEISS). After completion of chemotherapy en bloc resection of the tumour was performed. The entire surgical specimen was completely examined at two levels by means of undecalcified sections, and assigned a grade for the effect of chemotherapy analogous to the grading of Salzer-Kuntschik et al. (1983). The quantitative analysis of tumour cell nuclei revealed two different patterns of nuclear sizes, which were correlated significantly with the chemotherapy response (P less than 0.002). Tumour cell nuclei of well responders were significantly larger and showed a greater variance in size (mean value 66 + 41 micron 2), than those of poor responders (mean value 38 + 18 micron 2). We conclude from our results that quantitative analysis and classification of nuclear size of osteosarcoma cells may be useful for predicting chemotherapy response in patients with osteosarcoma.

Adolescent↗