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Biomedical subjects

G Adams

Publications and source records attributed to G Adams.

At least 37 records · Page 2Linked to original sources
PubMed2000

Mesenchymal precursor cells in the blood of normal individuals.

STATEMENT OF FINDINGS: Mesenchymal precursor cells found in the blood (BMPCs) of normal persons adhere to plastic and glass and proliferate logarithmically in DMEM-20% fetal calf serum (FCS) without growth factors. They form cells with fibroblast-like and stromal morphology, which is not affected by eliminating CD34, CD3, or CD14 cells. Osteogenic supplements (dexamethasone, ascorbic acid, and beta-glycerophosphate) added to the culture inhibited fibroblast formation, and BMPCs assumed the cuboidal shape of osteoblasts. After 5 days in supplemented medium, the elutriated cells displayed alkaline phosphatase (AP), and the addition of bone morphogenetic protein (BMP)2 (1 ng) doubled AP production (P < 0.04). Two weeks later, 30% of the cells were very large and reacted with anti-osteocalcin antibody. The same cultures also contained sudanophlic adipocytes and multinucleated giant cells that stained for tartrate-resistant acid phosphatase (TRAP) and vitronectin receptors. Cultured BMPCs immunostain with antibodies to vimentin, type I collagen, and BMP receptors, heterodimeric structures expressed on mesenchymal lineage cells. In addition, BMPCs stain with anti-CD105 (endoglin), a putative marker for bone-marrow mesenchymal stem cells (MSCs).

Alkaline Phosphatase↗
PubMed2000

Immuno- and genetic therapy in autoimmune diseases.

Animal models of autoimmune disease have been developed that mimic some aspects of the pathophysiology of human disease. These models have increased our understanding of possible mechanisms of pathogenesis at the molecular and cellular level and have been important in the testing, development and validation of new immunotherapies. The susceptibility to develop disease in the majority of these models is polygenic as is the case in humans. The exceptions to this rule are gene knock outs and transgenic models of particular genes which, in particular genetic backgrounds, have also contributed to the understanding of single gene function and their possible contribution to pathogenesis. Gene therapy approaches that target immune functions are being developed with encouraging results, despite the polygenic nature of these diseases. Basically this novel immuno-genetic therapy harnesses the knowledge of immunology with the myriad of biotechnological breakthroughs in vector design and delivery. Autoimmune disease is the result of genetic dysregulation which could be controlled by gene therapy. Here we summarize the genetic basis of these human diseases as well as some of the best characterized murine models. We discuss the strategies for their treatment using immuno- and gene therapy.

Animals↗
PubMed1999

Shock wave permeabilization with ribosome inactivating proteins: a new approach to tumor therapy.

Extracorporeal shock waves are high-pressure pulses of microsecond duration clinically used for lithotripsy. Recently, shock waves been shown to cause a transient increase of the permeability of the cell membrane. We therefore hypothesized that shock waves might be able to transfer tumoricidal agents into tumor cells and examined this in vitro and in vivo. In vitro, the ribosome inactivating proteins gelonin and saporin were transferred into L1210, SSK2, and HeLa cells, and dose-response curves were established. The drug concentration that reduced the cell proliferation by 50% (IC50) was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the enhancement factors from shock wave application were calculated. It was found that shock waves enhanced the action of gelonin from 900-fold in L1210 cells to 40,000-fold in HeLa cells and the action of saporin from 300-fold in L1210 cells to 15,000-fold in HeLa cells. In vivo, the effect of gelonin and saporin was assessed in a murine tumor model. SSK2 fibrosarcoma tumors locally grown in C3H mice were treated with shock waves after i.p. administration of gelonin or saporin. Shock wave application delayed the tumor growth, and long-term remissions lasting >180 days were induced in 40% of the animals. In conclusion, shock waves enhanced the action of ribosome inactivating proteins and led to complete tumor remissions. The local transfer of toxic substances by shock waves into tumors constitutes a new approach to a local tumor therapy.

Animals↗
PubMed1999

Identification of a novel gene of the X,K-ATPase beta-subunit family that is predominantly expressed in skeletal and heart muscles.

We have identified the fifth member of the mammalian X,K-ATPase beta-subunit gene family. The human and rat genes are largely expressed in skeletal muscle and at a lower level in heart. The deduced human and rat proteins designated as beta(muscle) (beta(m)) consist of 357 and 356 amino acid residues, respectively, and exhibit 89% identity. The sequence homology of beta(m) proteins with known Na,K- and H,K-ATPase beta-subunits are 30.5-39.4%. Unlike other beta-subunits, putative beta(m) proteins have large N-terminal cytoplasmic domains containing long Glu-rich sequences. The data obtained indicate the existence of hitherto unknown X,K-ATPase (most probably Na,K-ATPase) isozymes in muscle cells.

Amino Acid Sequence↗
PubMed1999

Choosing the optimal wound dressing for irradiated soft tissue wounds.

This article reviews the healing state of the previously irradiated wound, the tenets for optimal wound care, and the choices of wound dressings now available for its management. The goal in assisting a previously irradiated surgical wound to heal is to transform its chronic wound state into an acute wound state. This transformation encourages wound healing to proceed. Six major moisture-retentive dressing categories exist to optimize its healing. They are classified into the alginates, foams, gauzes, hydrogels, hydrocolloids, and transparent films. Optimal wound care management for previously irradiated wounds involves (1) adequately debriding and cleansing the local wound, (2) accurately assessing the wound, (3) choosing the appropriate dressing based on the wound assessment, and (4) encouraging granulation tissue formation and reepithelialization.

Aged↗
PubMed1999

Hyperkalaemic periodic paralysis in homozygous and heterozygous horses: a co-dominant genetic condition.

Historical, clinical and experimental data were collected from 9 horses homozygous for HYPP (H/H). All showed episodes of respiratory stertor, described as a rattling or honking sound, usually within the first week post partum. Five horses had one or more episodes of dysphagia, in 3 horses this was accompanied by drooling and in 3 by weight loss. In comparison, only one of 35 contemporaneous half siblings (of which approximately half would be expected to be of the H/N genotype and half N/N) was observed to have respiratory stertor prior to weaning and none had problems with dysphagia. One mature homozygous stallion was infertile secondary to urospermia. Six homozygous horses died or were subjected to euthanasia; 4 age less than a year, one age 20 months and one age 5 years. The remaining 3 cases were still alive at the end of the study. A comparison of homozygous and heterozygous horses using standardised potassium chloride challenge testing indicated that during attacks homozygotes showed significantly more frequent signs of drooling, prolapse of the third eyelid, respiratory stridor and weakness than heterozygous horses. Homozygotes also had significantly more total abnormalities (including myotonic discharges, high frequency repetitive discharges, and spontaneous activity) on electromyographic examination than heterozygotes. These data imply that HYPP is inherited as a codominant genetic defect, because the homozygotes showed more severe clinical signs of disease than heterozygotes. Homozygous foals would be expected to be produced in 25% of matings in which both parents are heterozygous. Owners and veterinarians should be aware of the risks of this mating.

Animals↗
PubMed1999

Insulin delivery governed by covalently modified lectin-glycogen gels sensitive to glucose.

A glucose-sensitive gel formulation containing concanavalin A and glycogen has been reported previously. Precipitation resulting from the addition of concanavalin A to glycogen has been documented, but the formation of glucose-sensitive gels based on lectin-glycogen interactions is novel and used here in our studies. An improved in-vitro self-regulating drug-delivery system, using covalently modified glucose-sensitive gels based on concanavalin A and a polysaccharide displacement mechanism, is described. The successful use of the covalently modified gels addresses a problem identified previously where significant leaching of the mitogenic lectin from the gel membranes of non-coupled gels was encountered. Concanavalin A was covalently coupled to glycogen by use of derivatives of Schiff's bases. The resulting gels, like the non-coupled gels, were shown to undergo a gel-sol transformation in response to glucose. Insulin delivery was demonstrated using this covalently modified system in conditions of repeated glucose triggering at 20 degrees C and 37 degrees C. The magnitude of the response was less variable than for the dextran-based gels studied previously. The performance of this system has been improved in terms of concanavalin A leaching. This could, therefore, be used as the basis of the design of a self-regulating drug-delivery device for therapeutic agents used to treat diabetes mellitus.

Biological Transport↗
PubMed1999

[Whole pancreatic transplantation and islet transplantation. Experiment notes].

BACKGROUND: The results of pancreas transplantation have greatly improved in recent years. The path to further improvements goes through extensive experimental researches. METHODS: This study describes the effects of different procedures as hemodynamic asset and postoperative outcome. Twenty-nine swine underwent a total pancreatectomy, and were stratified into five groups. Group one (n = 5) served as control. Group two (n = 7) was autotransplanted. Group three (n = 6) and group four (n = 6) underwent allotransplantation; the first without immunosuppression and the second treated with cyclosporine and steroids. In group five (n = 5) Langerhans Islets transplantation was performed. RESULTS: Survival was different depending on which methodology was applied. The postoperative survival was 7 +/- 2 days in group one, 24 +/- 16 days in group two, 17 +/- 7 days in group three, 27 +/- 8 days in group four and 12 +/- 6 days in group five. CONCLUSIONS: The postoperative glucose control was normal in group two and group four while a severe diabetes appeared in group one (group 1 vs group 2: p < 0.05) and in group three during acute graft rejection after the 12th postoperative day (group 3 vs group 4: p < 0.05). Glycemia was slightly controlled in group five. The intraoperative hemodynamic status was evaluated at the time of pancreatectomy, harvesting, revascularization, and when surgery was over. Among the different parameters studied (mean arterial and pulmonary pressure, pulmonary wedge pressure, central venous pressure, cardiac output, oxygen extraction ratio, systemic vascular resistance, oxygen delivery and oxygen consumption), a statistically significant difference between group one and group five (p < 0.05) was observed.

Animals↗
PubMed1998

Final report of a phase II evaluation of paclitaxel in patients with advanced squamous cell carcinoma of the head and neck: an Eastern Cooperative Oncology Group trial (PA390).

BACKGROUND: A number of single agents have been tested in patients with carcinoma of the head and neck receiving palliative treatment. In general, 15-30% of patients achieve a partial response lasting 3-4 months. Treatment has not been shown to alter survival rates. It is clear that new drugs with potentially greater activity need to be identified. For this purpose, the Eastern Cooperative Oncology Group conducted a Phase II evaluation of paclitaxel. METHODS: Patients with recurrent, metastatic, or locally advanced, incurable squamous cell carcinoma of the head and neck were eligible. The dose and schedule tested was the maximum tolerable dose of 250 mg/m2 determined from Phase I trials using a 24-hour infusion schedule and granulocyte-colony stimulating factor support. Courses were given at 3-week intervals until progression of disease was documented. Dose modifications were specified for hematologic toxicity and for neurotoxicity. RESULTS: Thirty-four patients were registered on study and 30 were eligible. Severe or life-threatening granulocytopenia was the most frequent toxicity observed, occurring in 91% of patients. Prior to response evaluation, one patient died of sepsis and one died of a myocardial infarct. Response was observed in 40% of eligible patients (4 complete and 8 partial responses). The median duration of response was 4.5 months (range, 2-20 months), with a median survival of 9.2 months and a 1-year survival rate of 33%. CONCLUSIONS: These results indicate that paclitaxel is an active agent for the treatment of squamous cell carcinoma of the head and neck. Studies evaluating alternative infusion schedules and combination regimens currently are underway.

Adult↗
PubMed1998

A survey of UK manual therapists' practice of and attitudes towards manipulation and its complications.

BACKGROUND AND PURPOSE: Little is known about the practice of manipulation by UK physiotherapists. This study was conducted to discover current practice of, and attitudes towards, manipulation among UK manipulative therapists. METHODS: A postal questionnaire was sent to 300 UK manipulative therapists who were members of two professional associations representing differing approaches to manual therapy: the Society of Orthopaedic Medicine (SOM) and the Manipulation Association of Chartered Physiotherapists (MACP). RESULTS: A 50% response rate was achieved and 129 respondents identified themselves as 'users' of manipulation. Anxiety about possible complications was a prominent reason adduced by 'non-users' and 'partial users' for their avoidance of manipulative procedures. The thoracic spine was the region most often manipulated, followed by the lumbar spine. Nineteen per cent of users had encountered complications from manipulation, which were most common in the cervical region and were predominantly non-serious. The majority of SOM members and a minority of MACP members used generalized cervical rotary manipulations--thought by some to be potentially dangerous. Attitudes to manipulation were generally positive, although overall respondents were uncertain as to whether its benefits outweighed its risks. Members of the SOM emerged as more frequent users of manipulation and as less conservative in their attitudes to certain aspects of manipulation. CONCLUSIONS: Allowing for possible under-reporting or other response biases, spinal manipulation emerged as a relatively safe and widely practised technique among this sample.

Attitude of Health Personnel↗
PubMed1998

Primary pneumococcal peritonitis complicated by exudative pleural effusion in an adolescent girl.

A healthy, young adolescent girl developed primary pneumococcal peritonitis, an infection rarely reported in this age group in North America. Her course was further complicated by exudative pleural effusion and pneumonia despite receiving 10 days of clindamycin therapy. Laparascopy proved useful in making the initial diagnosis, but may have contributed to the pathogenesis of the pulmonary process. Case presentation, management, and etiology are discussed.

Adolescent↗
PubMed1998

A therapeutic trial of radiation therapy with Vincristine, etoposide, and Procarbazine (VVP) in high grade intracranial gliomas--an Eastern Cooperative Oncology Group Study (E2392).

This study is a combined modality Phase II therapeutic trial to determine the efficacy of the novel combination of VP-16, Vincristine and Procarbazine in addition to postoperative radiation therapy in patients with high grade intracranial gliomas. Thirty three patients (median age 51 years) were entered (27 with glioblastoma multiforme, 6 with anaplastic astrocytoma). Toxicity was manageable with no lethal toxicities. Five of seven life threatening toxicities were hematologic. Median overall survival was 14.2 months. These data suggest this regimen is effective treatment for patients with high grade gliomas.

Administration, Oral↗
PubMed1998

Prevention of collagen-induced arthritis by gene delivery of soluble p75 tumour necrosis factor receptor.

Collagen type II-induced arthritis (CIA) in DBA/1 mice can be passively transferred to SCID mice with spleen B- and T-lymphocytes. In the present study, we show that infection ex vivo of splenocytes from arthritic DBA/1 mice with a retroviral vector, containing cDNA for the soluble form of human p75 receptor of tumour necrosis factor (TNF-R) before transfer, prevents the development of arthritis, bone erosion and joint inflammation in the SCID recipients. Assessment of IgG subclass levels and studies of synovial histology suggest that down-regulating the effector functions of T helper-type 1 (Th1) cells may, at least in part, explain the inhibition of arthritis in the SCID recipients. In contrast, the transfer of splenocytes infected with mouse TNF-alpha gene construct resulted in exacerbated arthritis and enhancement of IgG2a antibody levels. Intriguingly, infection of splenocytes from arthritic DBA/1 mice with a construct for mouse IL-10 had no modulating effect on the transfer of arthritis. The data suggest that manipulation of the immune system with cytokines, or cytokine inhibitors using gene transfer protocols can be an effective approach to ameliorate arthritis.

Adoptive Transfer↗
PubMed1998

Chemoradiotherapy versus radiotherapy in patients with advanced nasopharyngeal cancer: phase III randomized Intergroup study 0099.

PURPOSE: The Southwest Oncology Group (SWOG) coordinated an Intergroup study with the participation of Radiation Therapy Oncology Group (RTOG), and Eastern Cooperative Oncology Group (ECOG). This randomized phase III trial compared chemoradiotherapy versus radiotherapy alone in patients with nasopharyngeal cancers. MATERIALS AND METHODS: Radiotherapy was administered in both arms: 1.8- to 2.0-Gy/d fractions Monday to Friday for 35 to 39 fractions for a total dose of 70 Gy. The investigational arm received chemotherapy with cisplatin 100 mg/m2 on days 1, 22, and 43 during radiotherapy; postradiotherapy, chemotherapy with cisplatin 80 mg/m2 on day 1 and fluorouracil 1,000 mg/m2/d on days 1 to 4 was administered every 4 weeks for three courses. Patients were stratified by tumor stage, nodal stage, performance status, and histology. RESULTS: Of 193 patients registered, 147 (69 radiotherapy and 78 chemoradiotherapy) were eligible for primary analysis for survival and toxicity. The median progression-free survival (PFS) time was 15 months for eligible patients on the radiotherapy arm and was not reached for the chemo-radiotherapy group. The 3-year PFS rate was 24% versus 69%, respectively (P < .001). The median survival time was 34 months for the radiotherapy group and not reached for the chemo-radiotherapy group, and the 3-year survival rate was 47% versus 78%, respectively (P = .005). One hundred eighty-five patients were included in a secondary analysis for survival. The 3-year survival rate for patients randomized to radiotherapy was 46%, and for the chemoradiotherapy group was 76% (P < .001). CONCLUSION: We conclude that chemoradiotherapy is superior to radiotherapy alone for patients with advanced nasopharyngeal cancers with respect to PFS and overall survival.

Adolescent↗
PubMed1998

[The hemodynamic effects of the in-vivo administration of insulin-like growth-factor I].

BACKGROUND: Recent studies have demonstrated that IGF-I has several biological activities that correlate with the GH axis, by acting as a cell protecting factor and a promoting compound in different tissues and organs. Our latest findings have demonstrated a potential application of IGF-I in the treatment of postischemic renal injury, which frequently appears after a kidney transplant. The beneficial effect of the renal postoperative recovery probably correlates with the regulation of the vascular tone, in which IGF-I plays a role with other cytokines. However, this rises the question whether IGF-I has any effect on the general hemodynamic status. This study was designed to underline the intraoperative hemodynamic effect of exogenous IGF-I in an experimental setting of renal transplantation in swine. METHODS: Twelve female swine underwent a left renal autotransplantation. At the reperfusion the animals were separated in two groups. Group one served as control. Group two received 400 micrograms of IGF-I (added to the flushing solution). The animals were kept under complete hemodynamic monitoring over the operation. RESULTS: Among the different parameters studied (mean arterial pressure, mean pulmonary arterial pressure, pulmonary wedge pressure, central venous pressure, cardiac output, oxygen extraction ratio, systemic vascular resistance, oxygen delivery and oxygen consumption), any statistically significant difference between group one and two were observed. CONCLUSIONS: While the clinical administration of IGF-I requires further studies, the in vivo administration of this peptide is apparently well tolerated, and does not cause any hemodynamic instability to the operation.

Analysis of Variance↗