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Biomedical subjects

R E Allen

Publications and source records attributed to R E Allen.

At least 19 recordsLinked to original sources
PubMed2001

Mechanical stretch induces activation of skeletal muscle satellite cells in vitro.

Cultured quiescent satellite cells were subjected to mechanical stretch in a FlexerCell System. In response to stretch, satellite cells entered the cell cycle earlier than if they were under control conditions. Only a brief period of stretch, as short as 2 h, was necessary to stimulate activation. Additionally, conditioned medium from stretched cells could activate unstretched satellite cells. The presence of HGF on c-met-positive myogenic cells was detected by immunofluorescence at 12 h in culture, and immunoblots demonstrated that HGF was released by stretched satellite cells into medium. Also, stretch activation could be abolished by the addition of anti-HGF antibodies to stretched cultures, and activity in conditioned medium from stretched cells could be neutralized by anti-HGF antibodies. In addition, stretch appeared to cause release of preexisting HGF from the extracellular matrix. These experiments suggest that HGF may be involved in linking mechanical perturbation of muscle to satellite cell activation.

Animals↗
PubMed2001

Micrometastasis to in-transit lymph nodes from extremity and truncal malignant melanoma.

BACKGROUND: The sentinel lymph node (SLN) is the first lymph node in the regional nodal basin to receive metastatic cells. In-transit nodes are found between the primary melanoma site and regional nodal basins. To date, this is one of the first reports on micrometastasis to in-transit nodes. METHODS: Retrospective database and medical records were reviewed from October 21, 1993, to November 19. 1999. At the UCSF Melanoma Center, patients with tumor thickness > 1 mm or < 1 mm with high-risk features are managed with preoperative lymphoscintigraphy, selective SLN dissection, and wide local excision. RESULTS: Thirty (5%) out of 557 extremity and truncal melanoma patients had in-transit SLNs. Three patients had positive in-transit SLNs and negative SLNs in the regional nodal basin. Two patients had positive in-transit and regional SLNs. Three patients had negative in-transit SLNs but positive regional SLNs. The remaining 22 patients were negative for in-transit and regional SLNs. CONCLUSIONS: In-transit SLNs may harbor micrometastasis. About 10% of the time, micrometastasis may involve the in-transit and not the regional SLN. Therefore, both in-transit and regional SLNs should be harvested.

Extremities↗
PubMed2000

HGF is an autocrine growth factor for skeletal muscle satellite cells in vitro.

Muscle satellite cell activation following injury is essential for muscle repair, and hepatocyte growth factor/scatter factor (HGF) was the first growth factor shown to be able to stimulate activation and early division of adult satellite cells in culture and in muscle tissue. In addition, HGF was shown to be present in uninjured and injured skeletal muscle. Experiments in this report demonstrate that cultured satellite cells also synthesize and secrete HGF. Reverse transcription-polymerase chain reaction (RT-PCR) was used to demonstrate the presence of HGF mRNA in cultured adult satellite cells as early as 12 h from the time of plating. Message content was detectable at early times in culture and appeared to increase between 36 and 48 h. HGF protein expression was demonstrated during this time period by immunofluorescence localization; HGF was localized to mononucleated cells and multinucleated myotubes. HGF message was not detectable in muscle-derived fibroblast clones, and fibroblast-like cells in satellite cell cultures were negative for HGF by immunofluorescence analysis. Furthermore, Western blot analysis revealed the presence of HGF in satellite cell culture conditioned medium, associated with the cell surface and inside cells. Finally, the addition of neutralizing HGF antibodies during the proliferation phase in culture (42-90 h) significantly reduced cell proliferation. These experiments indicate that HGF is expressed by cultured satellite cells and that endogenous HGF from satellite cells can act in an autocrine fashion. Because HGF plays a central role in satellite cell activation, it is likely that direct administration of HGF into damaged muscle may represent a potentially useful approach for stimulating muscle repair. This approach may also be useful in enhancing the efficiency of myoblast transplantation in vivo.

Animals↗
PubMed1999

Outpatient combination chemoimmunotherapy for patients with metastatic melanoma. Results of a phase I/II trial.

BACKGROUND: Few studies have examined the feasibility, safety, and efficacy of an outpatient biochemotherapy regimen of low dose, subcutaneously administered interleukin-2 (IL-2) for patients with metastatic (Stage IV) melanoma. METHODS: Nineteen patients were treated with intravenous cisplatin and dacarbazine (DTIC), oral tamoxifen, and subcutaneous IL-2 and interferon-alpha-2b (IFN). Eligibility requirements included bidimensionally measurable metastatic melanoma, a Karnofsky performance score of 60 or higher, absence of significant cardiac or pulmonary dysfunction, no prior DTIC or cisplatin chemotherapy, and no evidence of central nervous system involvement. Patients were given a minimum of 2 6-week cycles. Treatment was continued in the absence of progressive disease, and patients were monitored for response at two-cycle intervals. RESULTS: Of the 19 patients, 1 (5%) achieved a complete response; 6 (32%) a partial response; 3 (16%) stable disease; and 9 (47%) progressive disease, for an overall response proportion of 37% (95% confidence interval, 16-61%). The median survival of the treated cohort was 10.6 months. The mean time to disease progression for patients with stable disease or better was 8.4 months, with a mean response duration of 5.1 months. The most common toxicities noted were constitutional symptoms, weight loss, nausea, neutropenia, and fatigue. The 19 patients received a total of 59 cycles of treatment, and IL-2, IFN, or both were held in 14 of these cycles secondary to Grade 3 or 4 toxicities. In addition, six patients required dose reduction of IL-2 and/or IFN. CONCLUSIONS: Chemoimmunotherapy consisting of cisplatin, DTIC, and tamoxifen combined with subcutaneous IL-2 and IFN can be safely administered in an outpatient setting. The described regimen yields moderate activity in metastatic melanoma, and efforts to improve its efficacy merit further examination.

Adult↗
PubMed1999

Microinjection of calpastatin inhibits fusion in myoblasts.

Rat satellite cells (RSC) were microinjected with purified calpastatin or m-calpain, and myoblasts from a C2C12 mouse line were microinjected with purified calpastatin. Microinjection with calpastatin completely prevented fusion of myoblasts from both sources, whereas microinjection with m-calpain significantly increased the rate of fusion of cultured RSC; 44% of the nuclei of RSC cultures were in multinucleated myotubes within 48 h after microinjection with m-calpain plus labeled dextran, whereas only 15% of the nuclei were in multinucleated myotubes after microinjection with dextran alone. Western analyses indicated that neither RSC nor C2C12 myoblasts contained detectable amounts of mu-calpain before fusion. The levels of calpastatin in C2C12 myoblasts increased as cells passed from the proliferative stage to the onset of fusion, and these levels increased substantially in both the C2C12 and the RSC cells as they progressed to the late or postfusion stage. Both RSC and C2C12 myoblasts contained an 80-kDa polypeptide that was labeled with an anti-m-calpain antibody in Western blots. The results are consistent with a role of the calpain system (m-calpain in these myoblast lines) in remodeling of the cytoskeletal/plasma membrane interactions during cell fusion.

Animals↗
PubMed1999

Discordancy between clinical predictions vs lymphoscintigraphic and intraoperative mapping of sentinel lymph node drainage of primary melanoma.

OBJECTIVE: To evaluate discordancy between clinical predictions and lymphatic drainage patterns of primary cutaneous melanoma as determined by preoperative lymphoscintigraphy and intraoperative lymphatic mapping of sentinel lymph nodes (SLNs). DESIGN: Before selective SLN dissection, 226 consecutive patients with melanoma underwent preoperative lymphoscintigraphy. SETTING: Teaching hospital tertiary care center. MAIN OUTCOME MEASURE: Correlation of lymphatic drainage patterns from the following 3 data sources: clinical predictions preoperatively based on anatomical location of primary melanoma, lymphatic drainage patterns as determined by preoperative lymphoscintigraphy, and identification of SLNs during surgery. RESULTS: Preoperative lymphoscintigraphy was successful in identifying at least 1 SLN in all 226 patients. In head and neck melanomas, at least 1 SLN was identified in an area outside what would have been clinically predicted in 11 (36.7%) of 30 cases. Discordancy for trunk melanomas was seen in 24 (25.3%) of 95 cases. Extremity melanomas showed drainage to unexpected SLNs in 6 (13.6%) of 44 and 3 (5.3%) of 57 patients for the upper and lower extremities, respectively. The overall rate of discordancy was 44 (19.5%) of 226. The SLNs were identified in surgery in all but 4 cases. CONCLUSIONS: Discordancy is most frequent in melanomas of the head and neck region, followed by that of the trunk. Preoperative lymphoscintigraphy identifies the occasional cases in the upper and lower extremities where drainage occurs to a basin that is not clinically predictable. Preoperative lymphoscintigraphy is a prerequisite for characterizing the lymphatic drainage pattern in patients with primary melanoma, especially for sites such as head and neck as well as trunk, before selective SLN dissection.

Adolescent↗
PubMed1999

Skeletal muscle satellite cell proliferation in response to members of the fibroblast growth factor family and hepatocyte growth factor.

Fibroblast growth factors (FGF) have the ability to regulate satellite cell proliferation in culture and in muscle tissue, but the specific FGF receptors (FGFR) expressed by adult rat muscle satellite cells and the action of members of the FGF family have not been assessed. Therefore, the expression of FGF receptors 1-4 was examined in proliferating satellite cells in culture, and the effects of eight members of the fibroblast growth factor family (FGFs1, 2, 4, 5, 6, 7, 8, and 9) on adult rat muscle satellite cells were evaluated. In addition, the interactions of FGFs with hepatocyte growth factor (HGF) were described. Of the eight FGFs evaluated, 1, 2, 4, 6, and 9 significantly (P < 0.05) stimulated proliferation above control. FGFs5, 7, and 8 displayed no mitogenic activity. Furthermore, combinations of HGF with FGFs2, 4, 6, or 9 stimulated satellite cell proliferation above that of optimal concentrations of HGF alone. Expression of four FGFR genes was detected in satellite cell cultures by reverse-transcription-polymerase chain reaction (RT-PCR). FGFR1 and FGFR4 were the most prominent forms expressed, and FGFR2 was only expressed at low levels. FGFR3 was difficult to detect. FGFR1 and FGFR2 were also expressed in muscle-derived fibroblasts, but FGFR4 and FGFR3 were not. In proliferating cultures of satellite cells, HGF, insulin-like growth factor I (IGF-I) and FGF1 stimulated significantly (P < 0.05) higher levels of FGFR1 message content, relative to control conditions, and platelet-derived growth factor-BB (PDGF-BB) and insulin-like growth factor (IGF-II) significantly (P < 0.05) depressed FGFR1 expression. During the activation period of satellite cell growth in culture (0-48 h), FGFR1 message content significantly (P < 0.05) increased from less than 1,000 copies per cell to approximately 5,000 copies per cell between 18 and 48 h, and HGF treatment significantly (P < 0.05) accelerated the accumulation of FGFR1 message during this period.

Animals↗
PubMed1999

Recombinant human granulocyte macrophage-colony stimulating factor (rhGM-CSF) and autologous melanoma vaccine mediate tumor regression in patients with metastatic melanoma.

In mice, significant immunoprotection was achieved using B16 melanoma cells transfected with granulocyte-macrophage colony-stimulating factor (GM-CSF) as vaccines (Dranoff G, Jaffee E, Lazenby A, et al. Vaccination with irradiated tumor cells engineered to secrete murine granulocyte-macrophage colony-stimulating factor stimulates potent, specific, and long-lasting anti-tumor immunity. Proc Natl Acad Sci USA 1993;90:3539-43). The aim of this study is to test the hypothesis that recombinant human GM-CSF (rhGM-CSF) injected with autologous melanoma vaccine may result in tumor rejection in melanoma patients. Twenty stage IV melanoma patients were treated as outpatients with multiple cycles of autologous melanoma vaccine and bacillus Calmette-Guérin (BCG) plus rhGM-CSF injection in the vaccine sites. Two patients (10%) showed a complete response, with one patient showing resolution of subcutaneous, hepatic, and splenic metastases. In the second patient, buccal, subcutaneous, pulmonary, paraaortic, hepatic, splenic, and retroperitoneal metastases regressed completely. Two patients (10%) showed partial response, with regression of a paraaortic metastasis in one patient. In the second patient, there was shrinkage (> 75%) of a large hepatic lesion. One patient has been rendered free of disease after resection of a single pulmonary metastatic nodule. Three patients (15%) had stable disease during treatment but subsequently developed progression of disease. In 12 patients (60%), the disease progressed. Side effects were minimal. In a separate pilot study, 15 stage IV melanoma patients were also treated with autologous melanoma vaccine with BCG but not with rhGM-CSF; none responded. The fact that four patients showed objective responses to active specific immunotherapy with rhGM-CSF demonstrates that melanoma patients bearing a significant tumor burden may respond specifically to their autologous melanoma.

Adult↗
PubMed1999

The health status of Gulf War veterans: lessons learned from the Department of Veterans Affairs Health Registry.

OBJECTIVE: To describe the demographic characteristics and postwar health status of U.S. Gulf War veterans who participated in the Department of Veterans Affairs health examination registry program. DESIGN: Case records of 52,835 veterans who participated in a standardized health examination program were reviewed. SETTING: Participants volunteered for physical examinations at a Department of Veterans Affairs medical treatment facility from August 1992 to September 1996. SUBJECTS: U.S. Gulf War veterans deployed to southwest Asia between August 1990 and 1996. MAIN OUTCOME MEASURE: Demographic, military, symptom, and International Classification of Diseases, Ninth Revision, Clinical Modification, diagnostic categories. RESULTS: A wide variety of symptoms and diagnoses were reported without apparent internal variation by military characteristics (branch and service component). The frequency of symptoms (fatigue, skin rash, headache, muscle and joint pain, and memory loss) reported increased over time, whereas the proportion of individuals with physician-diagnosed illnesses remained fairly constant. No single category of disease increased or decreased substantially over time. CONCLUSIONS: Veterans have experienced a wide variety of health problems since their Gulf War service. These problems, in aggregate, are different from what has been seen in other armed conflicts. The Department of Veterans Affairs registry is a very large case series and has failed to identify a single, unique syndrome or new illness after Gulf War service. An epidemiologic study would better define the prevalence of specific symptoms and medical conditions among Gulf War veterans and to what extent any of the conditions identified are associated with Gulf War military service. The knowledge provided by such studies would be important to development of preventive measures and future deployment medical surveillance planning.

Adult↗
PubMed1998

HGF/SF is present in normal adult skeletal muscle and is capable of activating satellite cells.

We have shown that hepatocyte growth factor/scatter factor can stimulate activation and early division of adult satellite cells in culture, and that the action of hepatocyte growth factor/scatter factor is similar to the action of the unidentified satellite cell activator found in extracts of crushed muscle. We now provide new evidence that hepatocyte growth factor/scatter factor is present in uninjured adult rat skeletal muscle and that the activating factor in crushed muscle extract is hepatocyte growth factor/scatter factor. Immunoblots of crushed muscle extract demonstrate the presence of hepatocyte growth factor/scatter factor. Furthermore, crushed muscle extract stimulates the scattering of cultured MDCK cells. Immunolocalization studies with adult rat skeletal muscle show the presence of hepatocyte growth factor/scatter factor in the extracellular matrix surrounding muscle fibers; in addition, the receptor for hepatocyte growth factor/scatter factor, c-met, is localized to putative satellite cells. In muscle from mdx mice, hepatocyte growth factor/scatter factor and c-met are colocalized in activated satellite cells in regions of muscle repair. Moreover, the satellite cell-activating activity of crushed muscle extract is abolished by preincubation with anti-hepatocyte growth factor antibodies. Finally, direct injection of hepatocyte growth factor/scatter factor into uninjured tibialis anterior muscle of 12-month-old rats stimulated satellite cell activation. These experiments demonstrate that hepatocyte growth factor/scatter factor is present in muscle, can be released upon injury, and has the ability to activate quiescent satellite cells in vivo.

Animals↗
PubMed1997

Optimal selective sentinel lymph node dissection in primary malignant melanoma.

OBJECTIVE: To determine the optimal approach of selective sentinel lymph node (SLN) dissection in primary malignant melanoma. DESIGN: Consecutive patient study. Prior to selective SLN dissection and wide local excision of the primary melanoma biopsy site, technetium Tc 99m sulfur colloid was injected intradermally around the primary melanoma or biopsy site to mark the SLN. Isosulfan blue (Lymphazurin, Hirsch Industries Inc, Richmond, Va) was injected at the primary biopsy site immediately before the surgical procedure. SETTING: Teaching hospital tertiary care referral center. MAIN OUTCOME MEASURES: Successful identification of SLNs being defined as positive for microscopic metastatic melanoma by blue dye staining, radioisotope uptake, or both. RESULTS: Selective intraoperative mapping by gamma probe and visualization of blue dye-stained SLN(s) resulted in a 98% (160/163) successful identification rate. Thirty patients (18.4%) had microscopic metastatic melanoma of the SLN(s), 22 of whom had subsequently completed lymphadenectomy. In 4 (18.2%) of these 22 patients, further microscopic metastatic disease was found in 1 of 8 nodes, 1 of 8 nodes, 1 of 28 nodes, and 1 of 9 nodes. No notable complications were encountered. Five recurrent cases from patients with SLNs without microscopic metastatic melanoma (3.8%) and 2 from patients with SLNs with microscopic metastatic melanoma (6%) were found during a median follow-up period of 463 days. A second primary melanoma developed in 2 patients; neither had no local recurrence. CONCLUSIONS: Sequential combination of preoperative lymphoscintigraphy and intraoperative mapping is a reliable way to identify regional SLN. The frequency of microscopic metastatic melanoma of the SLN(s) is 18.4%. Gamma-probe--guided resection minimizes the extent of lymph node dissection. Further follow-up is needed to assess the outcome of this group of patients for regional and systemic recurrences.

Adult↗
PubMed1997

Sympathetic blockade does not enhance tissue warming during isolated heated limb perfusion.

UNLABELLED: Isolated, heated limb perfusion is used for the treatment of locally recurrent melanoma, intransit metastases, and acral lentiginous melanomas. Tissue warming during this procedure requires adequate perfusion within the isolated extremity. At our institution, spinal or epidural anesthesia was used to produce sympathetic blockade and vasodilation for lower extremity procedures. More recently, we began using mild systemic hyperthermia to produce active thermoregulatory vasodilation. In the presence of heat stress, sympathetic blockade may actually decrease skin blood flow because active cutaneous vasodilation, which is associated with sweating, is dependent on intact sympathetic innervation. We therefore investigated whether the continued use of neuraxial blockade was justified. Twenty patients undergoing lower extremity perfusions were alternately assigned to receive either combined general and spinal anesthesia or general anesthesia alone. All were aggressively warmed using forced air and circulating water. There were no significant differences in tissue temperatures (measured at four sites in the isolated limb) between groups at any time before or after the start of perfusion. Similarly, pump flow (715 +/- 211 mL/min versus 965 +/- 514 mL/min) and the time required to achieve an average tissue temperature of 39 degrees C (43 +/- 16 vs 34 +/- 13 min) were not different between groups (spinal versus no spinal). Sweating was observed in all but three patients at esophageal temperatures of 37.9 +/- 0.6 degrees C. We conclude that sympathetic blockade confers no added benefit for tissue warming during isolated limb perfusions in the presence of induced mild systemic hyperthermia. IMPLICATIONS: Sympathetic blockade prevents adrenergic vasoconstriction, but also inhibits active, neurally mediated cutaneous vasodilation (a normal thermoregulatory response to heat). In slightly hyperthermic patients, we demonstrated that spinal anesthesia does not improve convective tissue warming during isolated, heated limb perfusion. Mild systemic hyperthermia may promote greater vasodilation than sympathetic blockade.

Anesthesia, General↗
PubMed1997

Integrated mental health care: practitioners' perspectives.

OBJECTIVE: Integrated mental health care (IMHC) is a community-based model that considers the patient and informal carers to be the major contributors to stable recovery from severe mental health problems. This study investigates the implementation of IMHC by 35 New Zealand practitioners 1 year after being trained in the model. It also explores their experiences and perceptions regarding the model. METHOD: Quantitative and qualitative data were gathered by combining a questionnaire survey with in-depth interviews. RESULTS: Few of the trainees had been able to implement the model as much as they would have liked. A primary barrier to implementation was created by the resource constraints that impede most innovative community care initiatives even when demonstrated to be more cost-effective than traditional hospital-based approaches. Concerns particular to IMHC included issues relating to flexibility, time-intensiveness and applicability to New Zealand. Many practitioners found some of the specific intervention strategies and the clear overall structure of the model useful. Its psychosocial emphasis had a positive impact on many practitioners' beliefs about the causes and prognosis of severe mental health problems. CONCLUSIONS: Participants offer a range of recommendations as to how IMHC might be applied and adapted. Consultation with staff, consumers, families and Maori, as well as a strengthening of the psychosocial components, are recommended.

Attitude of Health Personnel↗
PubMed1996

A new minimally invasive open pelvic lymphadenectomy surgical technique for the staging of prostate cancer.

We report a new method for lymphadenectomy, the minilaparotomy (inguinal) pelvic lymph node dissection (MLPLND), and compare it with laparoscopic pelvic lymph node dissection (LPLND) in terms of cost, effectiveness, operation time and morbidity. We reviewed a series of 111 consecutive patients: 51 had MLPLND and 60 had LPLND. All patients had proved adenocarcinoma of the prostate by biopsy. Of the MLPLND patients, only 1 had to stay overnight in the hospital, and all left within 24 hours. Pelvic lymphadenectomy consisted of nodal removal along the internal iliac vessels and the external iliac vein, and nodes of the obturator foramen. A total of 14% of the patients had disease involving the lymph nodes. The cost of MLPLND was 50% of the cost of LPLND, with no interoperative or postoperative morbidity. This new operation can be performed thoroughly an inexpensively in approximately 35 minutes, with little or no morbidity. Since the drawbacks of laparoscopic techniques associated with instrument costs and the learning curve for this technically difficult operation are eliminated, staging pelvic lymphadenectomy can be performed routinely on a wider variety of patients with potential metastatic disease. Currently, we recommend MLPLND to any patient with a tumor of Gleason score 7 or higher or a serum prostate-specific antigen value of 15 ng/mL or higher.

Adenocarcinoma↗
PubMed1995

Hepatocyte growth factor activates quiescent skeletal muscle satellite cells in vitro.

The effect of hepatocyte growth factor (HGF) on the activation of quiescent rat skeletal muscle satellite cells was evaluated in vitro. Satellite cells from 9-month-old adult rats are quiescent in vivo and when cultured, display a protracted lag phase prior to division that is not present in satellite cells from neonatal or regenerating muscle. Under normal growth conditions, satellite cells divide for the first time between 42 and 60 hr. Hepatocyte growth factor increased proliferation in a dose-dependent fashion prior to 48 hr with half-maximal stimulation at approximately 3 ng/ml; in addition, heparin enhanced this activity. The time course of cyclin-D1 and proliferating cell nuclear antigen (PCNA) expression was accelerated in HGF-treated satellite cells, indicating that cells entered the cell cycle earlier. No significant effects on muscle-derived fibroblast proliferation was observed. The signalling receptor for HGF is the product of the c-met protooncogene, and rtPCR analysis of satellite cells 0-72 hr in culture demonstrated the presence of this message throughout this time period. The presence of c-met in quiescent satellite cells, the ability of HGF to stimulate precocious entry into the cell cycle, and the previously described localization of HGF message in regenerating muscle (Jennische et al., 1993) indicate that HGF could act as an activator of quiescent satellite cells in vivo.

Animals↗
PubMed1995

Activation of skeletal muscle satellite cells and the role of fibroblast growth factor receptors.

Specific, high-affinity binding of FGF2 was evaluated in cultured skeletal muscle satellite cells from young (3- to 4-week-old) and adult (9- to 12-month-old) rats prior to the first division in culture. Specific binding of FGF2 was detected on satellite cells from young rats at 18 h postplating, the earliest time examined, but specific binding was not detectable until 42 h on satellite cells from old rats. This correlates well with the delayed entry into the cell cycle exhibited by adult satellite cells and with the ability of satellite cells from rats of these ages to proliferate in response to FGF2. Patterns of tyrosine phosphorylation in whole cell extracts, following stimulation by FGF2, indicated specific FGF2 phosphorylation of proteins of 150/145, 90, 42, and 35 kDa in cells from both age groups. Several growth factors were evaluated for their ability to stimulate early entry of adult satellite cells into the cell cycle, and none of the following growth factors were able to activate proliferation of these cells: FGF2, IGF-1, IGF-2, PDGF-BB, TGF-beta 1, or TGF-beta 2. In addition, specific binding of FGF2 to 48-h cultures of adult satellite cells was not stimulated by FGF2, IGF-1, IGF-2, PDGF-BB, or TGF-beta 2, and specific binding was significantly decreased (P < 0.05) by FGF2 and TGF-beta 2. Specific binding was significantly lower in cells treated with PDGF-BB than in cells treated with either form of IGF but was greater than in cells treated with FGF2 or TGF-beta 2. The results of these experiments suggest that expression of functional FGF receptors on the surface of satellite cells may represent an important step in the activation of quiescent satellite cells.

Age Factors↗