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1.
Osteoporos Int ; 31(11): 2243-2250, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32564093

ABSTRACT

Sclerostin, a natural hormone made in bone, suppresses bone formation. Sclerostin is also decreased by estrogen. Progesterone, estrogen's menstrual partner, stimulates bone formation. It is unclear whether progesterone influences sclerostin. This study showed that progesterone did not change sclerostin using serum remaining from a randomized progesterone hot flush therapy trial. INTRODUCTION: Progesterone and sclerostin are both endogenous hormones acting through osteoblast-origin cells and promote or suppress bone formation, respectively. Estradiol suppresses sclerostin, but progesterone, its menstrual cycle partner hormone, has unclear sclerostin relationships. We postulated that progesterone therapy would influence serum sclerostin levels. METHODS: We obtained sclerostin levels for an ethics-approved post hoc analysis. Fasting sclerostin was measured in all remaining sera from a previous 12-week randomized controlled trial (RCT) of oral micronized progesterone (progesterone) for menopausal (> 1 year after last flow) vasomotor symptoms (VMS). Women in the RCT took 300 mg progesterone at bedtime or placebo (1:1) in a trial showing progesterone significantly decreased VMS. RESULTS: Participants were healthy menopausal, primarily Caucasian (91.2%) community-dwelling women (± SD), 55.2 ± 4.6 years old with BMI 24.9 ± 2.9 kg/m2. The baseline sclerostin level in 60 women was 28.41 ± 10.47 pmol/L. Baseline sclerostin was not correlated with the run-in VMS score (r = 0.143, P = 0.294). Paired baseline and 12-week RCT data for 52 women showed serum sclerostin levels did not change related to experimental therapy (P = 0.504). Changes in final sclerostin values adjusted for baseline were progesterone (- 1.07 ± 7.96 pmol/L) and placebo (- 2.64 ± 8.70 pmol/L). In observational data (n = 60), baseline sclerostin levels correlated with the General Framingham Cardiovascular (CVD) Risk score (r = - 0.398, P = 0.003) and self-reported health by SF-36 quality of life instrument (QoL, r = - 0.331, P = 0.016). CONCLUSION: Physiological oral micronized progesterone did not stimulate nor suppress serum sclerostin levels based on post hoc analysis of RCT data. Exploratory results, however, showed sclerostin negatively correlated with CVD risk and QoL. ClinicalTrials.gov #NCT0146469.


Subject(s)
Adaptor Proteins, Signal Transducing , Progesterone , Quality of Life , Adaptor Proteins, Signal Transducing/metabolism , Estradiol , Female , Hot Flashes/drug therapy , Humans , Menopause , Middle Aged , Progesterone/pharmacology , Progesterone/therapeutic use
2.
Biol Reprod ; 103(3): 630-642, 2020 08 21.
Article in English | MEDLINE | ID: mdl-32412043

ABSTRACT

The interaction of sperm with the oocyte is pivotal during the process of mammalian fertilization. The limited numbers of sperm that reach the fallopian tube as well as anatomic restrictions indicate that human sperm-oocyte encounter is not a matter of chance but a directed process. Chemotaxis is the proposed mechanism for re-orientating sperm toward the source of a chemoattractant and hence to the oocyte. Chemokines represent a superfamily of small (8-11 kDa), cytokine-like proteins that have been shown to mediate chemotaxis and tissue-specific homing of leukocytes through binding to specific chemokine receptors such as CCRs. Here we show that CCR6 is abundantly expressed on human sperms and in human testes. Furthermore, radioligand-binding experiments showed that CCL20 bound human sperm in a specific manner. Conversely, granulosa cells of the oocyte-surrounding cumulus complex as well as human oocytes represent an abundant source of the CCR6-specific ligand CCL20. In human ovaries, CCL20 shows a cycle-dependent expression pattern with peak expression in the preovulatory phase and CCL20 protein induces chemotactic responses of human sperm. Neutralization of CCL20 in ovarian follicular fluid significantly impairs sperm migratory responses. Conversely, analyses in infertile men with inflammatory conditions of the reproductive organs demonstrate a significant increase of CCL20/CCR6 expression in testis and ejaculate. Taken together, findings of the present study suggest that CCR6-CCL20 interaction may represent an important factor in directing sperm-oocyte interaction.


Subject(s)
Chemokine CCL20/genetics , Infertility, Male/genetics , Oocytes/physiology , Receptors, CCR6/genetics , Sperm-Ovum Interactions/genetics , Spermatozoa/physiology , Chemokine CCL20/antagonists & inhibitors , Chemokines/metabolism , Chemotaxis , Female , Follicular Fluid/metabolism , Follicular Phase/physiology , Gene Expression Regulation/genetics , Granulosa Cells/metabolism , Humans , Immunohistochemistry , Male , Microarray Analysis , Receptors, CCR6/antagonists & inhibitors , Spermatozoa/metabolism , Testis/metabolism
3.
J Clin Endocrinol Metab ; 99(2): E252-6, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24302746

ABSTRACT

CONTEXT: Sclerostin and Dickkopf 1 (DKK1) are antagonists of the canonical Wnt signaling pathway, both binding to the same low-density lipoprotein receptor-related protein 5/6 on osteoblasts, thereby inhibiting bone formation. It is not known whether there is an interaction between sclerostin and DKK1. OBJECTIVE: We examined whether a lack of sclerostin is compensated by increased DKK1 levels. DESIGN, SETTING, AND PATIENTS: We measured DKK1 levels in serum samples of patients and carriers of sclerosteosis (19 patients, 24 carriers) and van Buchem disease (VBD) (13 patients, 22 carriers) and 25 healthy controls. Sclerosteosis and VBD are caused by deficient sclerostin synthesis and are characterized by increased bone formation and hyperostotic phenotypes. MAIN OUTCOME MEASURES: DKK1 levels were compared between patients and carriers, and between patients and healthy controls. We also examined associations between levels of DKK1 and the bone turnover markers procollagen type 1 amino-terminal propeptide and carboxy-terminal cross-linking telopeptide. RESULTS: We found that DKK1 levels were significantly higher in patients with both sclerosteosis (4.28 ng/mL [95% confidence interval (CI), 3.46-5.11 ng/mL]) and VBD (5.28 ng/mL [95% CI, 3.84-6.71 ng/mL]), compared to levels in carriers of the two diseases (sclerosteosis, 2.03 ng/mL [95% CI, 1.78-2.29 ng/mL], P < .001; VBD, 3.47 ng/mL [95% CI, 2.97-3.97 ng/mL], P = 0.017) and to levels in healthy controls (2.77 ng/mL [95% CI, 2.45-3.08 ng/mL]; P = 0.004 and P < .001, respectively). Serum DKK1 levels were positively associated with levels of procollagen type 1 amino-terminal propeptide and carboxy-terminal cross-linking telopeptide in both disorders. CONCLUSIONS: These results suggest that increased DKK1 levels observed in patients with sclerosteosis and VBD represent an adaptive response to the increased bone formation characterizing these diseases, although these increased levels do not compensate for the lack of sclerostin on bone formation.


Subject(s)
Bone Morphogenetic Proteins/deficiency , Bone Remodeling/physiology , Hyperostosis/blood , Intercellular Signaling Peptides and Proteins/blood , Osteochondrodysplasias/blood , Syndactyly/blood , Adaptor Proteins, Signal Transducing , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Genetic Markers , Humans , Male , Middle Aged
4.
J Clin Endocrinol Metab ; 97(10): E1953-7, 2012 Oct.
Article in English | MEDLINE | ID: mdl-22844062

ABSTRACT

CONTEXT: Increased bone fragility is a frequent complication of hypercortisolism due predominantly to suppression of bone formation. Sclerostin is an osteocyte-produced negative regulator of bone formation, which is up-regulated by glucocorticoids in mice. OBJECTIVE: Our objective was to assess the effect of endogenous hypercortisolism on circulating sclerostin and bone turnover in humans. DESIGN: We measured sclerostin, ß-C-terminal telopeptide, amino-terminal propeptide of type 1 procollagen, and fibroblast growth factor 23 in blood samples of 21 patients with endogenous hypercortisolism and 21 age- and gender-matched controls. In 12 patients, measurements were repeated at various time intervals after successful surgical treatment (transsphenoidal surgery or adrenalectomy). RESULTS: Plasma sclerostin levels were significantly decreased in patients compared with controls (112±49 vs. 207±48 pg/ml, P<0.001). In the 12 patients who were evaluated after surgical treatment, sclerostin levels increased from 121.4±46.5 to 175.8±78.5 pg/ml (P=0.003). These changes in plasma sclerostin levels were accompanied by significant increases in levels of fibroblast growth factor 23 (from 44.2±12.2 to 84.0±58.8 pg/ml, P=0.017) and of the bone turnover markers amino-terminal propeptide of type 1 procollagen (from 31.7±18.2 to 94.2±92.2 ng/ml, P=0.037) and ß-C-terminal telopeptide (from 134.2±44 to 409.2±285 pg/ml, P=0.005). CONCLUSIONS: Contrary to the findings in mice, circulating sclerostin is decreased in patients with chronic endogenous hypercortisolism and increases after treatment. These findings suggest that in humans, chronic exposure to glucocorticoids affects the number or function of osteocytes rather than the production of sclerostin.


Subject(s)
Bone Morphogenetic Proteins/blood , Bone Remodeling/physiology , Cushing Syndrome/metabolism , Cushing Syndrome/surgery , Adaptor Proteins, Signal Transducing , Adrenalectomy , Adult , Animals , Collagen Type I/blood , Female , Fibroblast Growth Factor-23 , Fibroblast Growth Factors/blood , Genetic Markers , Humans , Hydrocortisone/blood , Male , Mice , Middle Aged , Osteocytes/physiology , Peptide Fragments/blood , Peptides/blood , Procollagen/blood
5.
Eur J Paediatr Neurol ; 16(6): 740-3, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22445802

ABSTRACT

Differential diagnosis of facial nerve palsy in children is extensive. We report on three pediatric cases presenting with facial nerve palsy caused by hyperostosis corticalis generalisata (Van Buchem disease). This autosomal recessive disease is characterized by progressive bone overgrowth, with narrowing of the neuroforamina in the skull causing cranial neuropathies. These three new cases of Van Buchem disease are of interest because of exceptionally early presentation of symptoms. Furthermore, this is the first report describing bilateral papilledema in a child with Van Buchem disease. Head computerized tomography (CT) scan revealed thickened calvarium, skull base and mandible in all three children, with narrowed facial nerve canals. Bone mineral density (BMD) was markedly increased at all measured points and biochemical markers of bone formation were significantly elevated. Diagnosis of Van Buchem disease was genetically confirmed. The cases are unique in that these are the first well-documented pediatric cases of Van Buchem disease.


Subject(s)
Facial Nerve Diseases/etiology , Facial Paralysis/etiology , Osteochondrodysplasias/complications , Anti-Inflammatory Agents/therapeutic use , Bone Density , Child , Child, Preschool , Female , Hearing Loss, Conductive/etiology , Humans , Infant , Male , Prednisone/therapeutic use , Recurrence , Skull/abnormalities , Tomography, X-Ray Computed
6.
Eur J Endocrinol ; 166(4): 711-6, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22267280

ABSTRACT

OBJECTIVE: Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fractures and thiazolidinediones (TZDs) increase this risk. TZDs stimulate the expression of sclerostin, a negative regulator of bone formation, in vitro. Abnormal sclerostin production may, therefore, be involved in the pathogenesis of increased bone fragility in patients with T2DM treated with TZDs. METHODS: We measured serum sclerostin, procollagen type 1 amino-terminal propeptide (P1NP), and carboxy-terminal cross-linking telopeptide of type I collagen (CTX) in 71 men with T2DM treated with either pioglitazone (PIO) (30 mg once daily) or metformin (MET) (1000 mg twice daily). Baseline values of sclerostin and P1NP were compared with those of 30 healthy male controls. RESULTS: Compared with healthy controls, patients with T2DM had significantly higher serum sclerostin levels (59.9 vs 45.2 pg/ml, P<0.001) but similar serum P1NP levels (33.6 vs 36.0 ng /ml, P=0.39). After 24 weeks of treatment, serum sclerostin levels increased by 11% in PIO-treated patients and decreased by 1.8% in MET-treated patients (P=0.018). Changes in serum sclerostin were significantly correlated with changes in serum CTX in all patients (r=0.36, P=0.002) and in PIO-treated patients (r=0.39, P=0.020), but not in MET-treated patients (r=0.17, P=0.31). CONCLUSIONS: Men with T2DM have higher serum sclerostin levels than healthy controls, and these levels further increase after treatment with PIO, which is also associated with increased serum CTX. These findings suggest that increased sclerostin production may be involved in the pathogenesis of increased skeletal fragility in patients with T2DM in general and may specifically contribute to the detrimental effect of TZDs on bone.


Subject(s)
Biomarkers/blood , Bone Morphogenetic Proteins/blood , Bone Remodeling/drug effects , Diabetes Mellitus, Type 2/blood , Metformin/pharmacology , Thiazolidinediones/pharmacology , Adaptor Proteins, Signal Transducing , Adult , Aged , Biomarkers/analysis , Biomarkers/metabolism , Bone Morphogenetic Proteins/analysis , Bone Remodeling/physiology , Bone and Bones/metabolism , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Double-Blind Method , Genetic Markers , Humans , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/pharmacology , Male , Metformin/administration & dosage , Metformin/adverse effects , Middle Aged , Pioglitazone , Thiazolidinediones/administration & dosage , Thiazolidinediones/adverse effects
7.
Eur J Endocrinol ; 163(5): 833-7, 2010 Nov.
Article in English | MEDLINE | ID: mdl-20817762

ABSTRACT

OBJECTIVE: In vitro and in vivo studies in animal models have shown that parathyroid hormone (PTH) inhibits the expression of the SOST gene, which encodes sclerostin, an osteocyte-derived negative regulator of bone formation. We tested the hypothesis that chronic PTH excess decreases circulating sclerostin in humans. DESIGN: We studied 25 patients with elevated serum PTH concentrations due to primary hyperparathyroidism (PHPT) and 49 patients cured from PHPT after successful parathyroidectomy (PTx; euparathyroid controls (EuPTH)). METHODS: We measured plasma PTH and serum sclerostin levels and the serum markers of bone turnover alkaline phosphatase, P1NP, and ß-CTX. RESULTS: As expected by the design of the study, mean plasma PTH was significantly higher (P<0.001) in PHPT patients (15.3 pmol/l; 95% confidence interval (CI): 11.1-19.5) compared with that of EuPTH controls (4.1 pmol/l; 95% CI: 3.6-4.5). PHPT patients had significantly lower serum sclerostin values compared with those in EuPTH subjects (30.5 pg/ml; 95% CI: 26.0-35.1 vs 45.4 pg/ml; 95% CI: 40.5-50.2; P<0.001) and healthy controls (40.0 pg/ml; 95% CI: 37.1-42.9; P=0.01). Plasma PTH concentrations were negatively correlated with serum sclerostin values (r=-0.44; P<0.001). Bone turnover markers were significantly correlated with PTH, but not with sclerostin. CONCLUSION: Patients with PHPT have significantly lower serum sclerostin values compared with PTx controls with normal PTH concentrations. The negative correlation between PTH and sclerostin suggests that SOST is downregulated by PTH in humans.


Subject(s)
Bone Morphogenetic Proteins/blood , Hyperparathyroidism, Primary/blood , Parathyroid Glands/metabolism , Parathyroid Hormone/blood , Adaptor Proteins, Signal Transducing , Adult , Aged , Biomarkers/blood , Bone Morphogenetic Proteins/antagonists & inhibitors , Bone Morphogenetic Proteins/biosynthesis , Bone Remodeling/physiology , Down-Regulation/physiology , Female , Genetic Markers , Humans , Hyperparathyroidism, Primary/diagnosis , Male , Middle Aged , Parathyroid Hormone/physiology
8.
J Laryngol Otol ; 123(8): 922-4, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19216817

ABSTRACT

OBJECTIVE: To discuss the technique and outcome of this simple procedure and the management of post-traumatic parotid sialocoeles, and to review the literature regarding this condition. CASE REPORT: We report the successful surgical treatment, by peroral drainage, of three patients with post-traumatic parotid sialocoele resistant to conservative management. DISCUSSION: We discuss the method and outcome of the surgical procedure performed, along with the causes, presentation and management of parotid sialocoele. CONCLUSION: Correct initial management of a parotid duct injury may prevent the formation of a sialocoele. When conservative treatment of post-traumatic parotid sialocoele fails, we advocate the surgical technique described in this report as it is effective, simple and carries minimal risk to the patient.


Subject(s)
Cysts/etiology , Drainage/methods , Salivary Gland Diseases/surgery , Adolescent , Aged , Cysts/surgery , Female , Humans , Male , Parotid Diseases/surgery , Parotid Gland/injuries , Parotid Gland/surgery , Salivary Ducts/surgery
9.
J Laryngol Otol ; 123(2): 177-81, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18485249

ABSTRACT

INTRODUCTION: This paper reviews our experience of ossicular chain injuries following head trauma treated at Groote Schuur Hospital, Cape Town, South Africa. MATERIALS AND METHODS: We performed a retrospective chart review of all patients with a history of head trauma and a conductive hearing loss who had undergone exploratory tympanotomy. Sixteen patients were included in the study. RESULTS: Injury was most common at the incudostapedial joint (63 per cent). Disarticulations of the icudostapedial joint were treated with cartilage interposition in all cases. Audiography showed an improvement in 12 of the patients, with an average improvement of 35 dB. DISCUSSION: We discuss the various options available to the otologist to repair ossicular disruptions after trauma. In this series, cartilage autografts were used in most incudostapedial joint injuries, with excellent closure of the air-bone gap. CONCLUSION: Cartilage interposition was a very successful method of repairing incudostapedial joint dislocation in this series, at short term follow up.


Subject(s)
Craniocerebral Trauma/complications , Ear Ossicles/injuries , Hearing Loss, Conductive/etiology , Adolescent , Adult , Craniocerebral Trauma/pathology , Craniocerebral Trauma/surgery , Ear Ossicles/pathology , Ear Ossicles/surgery , Female , Hearing Loss, Conductive/surgery , Humans , Joint Dislocations/surgery , Male , Middle Aged , Ossicular Replacement/adverse effects , Retrospective Studies , Temporal Bone/injuries , Time Factors , Treatment Outcome , Tympanoplasty/adverse effects
10.
J Laryngol Otol ; 123(3): 351-5, 2009 Mar.
Article in English | MEDLINE | ID: mdl-18384697

ABSTRACT

OBJECTIVE: To discuss the management and to review the literature regarding retained knife blades in the head and neck. CASE REPORT: We present three cases in which patients presented with retained knife blades in the head and neck region; in two of these, the diagnosis was delayed by more than eight weeks. In all patients, the retained knife blade was removed through the pathway of insertion, without significant sequelae. DISCUSSION: The methods of removal, appropriate radiological investigations and patient profiles are discussed. CONCLUSIONS: We propose that radiography be performed on all patients presenting with facial stab injuries which are anything more than superficial. We further suggest that the direct extraction of sharp objects through the pathway of insertion is safe if radiological studies show no risk of vascular injury.


Subject(s)
Facial Injuries/diagnostic imaging , Foreign Bodies/diagnostic imaging , Head Injuries, Penetrating/diagnostic imaging , Wounds, Stab/diagnostic imaging , Adult , Eye Injuries, Penetrating/diagnostic imaging , Eye Injuries, Penetrating/surgery , Facial Injuries/etiology , Foreign Bodies/surgery , Head Injuries, Penetrating/etiology , Humans , Male , Nasopharynx/diagnostic imaging , Nasopharynx/injuries , Pharynx/diagnostic imaging , Pharynx/injuries , Tomography, X-Ray Computed , Wounds, Stab/complications , Wounds, Stab/surgery
11.
J Laryngol Otol ; 122(2): 181-7, 2008 Feb.
Article in English | MEDLINE | ID: mdl-17517161

ABSTRACT

BACKGROUND: The buccinator musculomucosal flap is an axial-pattern flap based on either the buccal or the facial artery. We present our experience with this flap and describe its surgical anatomy, the surgical techniques utilised to raise the flap and its clinical applications. MATERIALS AND METHODS: We retrospectively reviewed all patients who had had buccinator myomucosal flaps created at the Groote Schuur Hospital between 1999 and 2004. Patients were also recalled to assess flap sensation and to record reduction of mouth opening as a consequence of donor site scarring. RESULTS: Of the 14 patients who had had a buccinator myomucosal flap created, there was one flap failure. Sensation was present in 71 per cent of flaps, and there was no trismus due to donor site scarring. CONCLUSIONS: The buccinator myomycosal flap is a dependable flap with good functional outcome and low morbidity.


Subject(s)
Facial Muscles/surgery , Mouth Neoplasms/surgery , Mouth/surgery , Plastic Surgery Procedures/methods , Surgical Flaps , Adult , Aged , Facial Muscles/pathology , Female , Humans , Male , Middle Aged , Mouth/pathology , Mouth Neoplasms/pathology , Recovery of Function , Retrospective Studies , Treatment Outcome
12.
S. Afr. j. surg. (Online) ; 46(1): 22-25, 2008.
Article in English | AIM (Africa) | ID: biblio-1270999

ABSTRACT

Total glossectomy (with or without total laryngectomy) followed by postoperative radiotherapy remains the principal treatment method for advanced base of tongue carcinoma. The procedure remains controversial owing to poor cure rates and the inevitable functional deficits associated with it. However; even though total glossectomy is a major surgical procedure that impacts on speech; deglutition and quality of life; it may offer patients the best chance of cure in many centres; especially in the developing world.METHODS. We did a retrospective chart review of all patients at Groote Schuur Hospital; Cape Town; who had undergone total glossectomy; with or without total laryngectomy; for stage IV squamous cell carcinoma (SCC) of the tongue between 1998 and 2004. RESULTS. Eight patients had a total glossectomy performed during the study period. At 2; 3 and 5 years 63; 38and 25of patients respectively were alive without disease. No patient required permanent nasogastric or gastrostomy feeding; and all returned to a full oral diet. Three of 5 patients who had laryngeal preservation and could be assessed for speech had intelligible speech. All but 1 patient (88) reported pain relief following surgical excision. Perineural invasion was present in 75; and 38had positive resection margins. Five patients had recurrence; 2 cervical; 1 local; and 2 local and cervical. Conclusion. Advanced SCC of the tongue is a devastating disease causing severe pain and disorders of speech and swallowing. Total glossectomy (with or without total laryngectomy) and postoperative radiotherapy is a reasonable treatment option; particularly in the developing world setting. It has cure rates superior to primary radiotherapy; and provides motivated patients with excellent pain relief and a reasonable quality of life


Subject(s)
Glossectomy , Surgical Procedures, Operative
13.
Cancer Immunol Immunother ; 46(3): 167-73, 1998 May.
Article in English | MEDLINE | ID: mdl-9625540

ABSTRACT

Squamous cell carcinomas of the head and neck (SCCHN) frequently display high levels of the epidermal growth factor receptor (EGFR). Since EGFR is expressed on the cell surface it may form a suitable target for anticancer therapy with anti-receptor monoclonal antibodies (mAb). Besides the interference with receptor/ligand interactions, binding of mAb to EGFR leads to immunoglobulin-coated tumour cells that may induce or enhance non-specific immune effector mechanisms like antibody-dependent cell-mediated cytotoxicity (ADCC). In established cell lines of SCCHN (UM-SCC 11B, 14C, 22B, and 8029 NA) we investigated the antitumour activity of allogeneic peripheral blood mononuclear cells (PBMC) in combination with rat (ICR 62), mouse (EMD 55900), and humanized (EMD 72000) anti-EGFR mAb. In addition, autologous PBMC were available for tumour line UD-SCC 4. The EGFR protein content of the tumour cell lines ranged between 170 fmol/mg protein and 8100 fmol/mg protein, and MCF-7 cells served as receptor-negative controls. PBMC activity against SCCHN targets was determined in 96-well microtitre-plate monolayer cultures by the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay after coincubation for 4 h, 24 h and 72 h at effector target ratios of 1:1, 5:1, 10:1 and 20:1. PBMC subpopulations were obtained by macrophage depletion (plastic adherence) or natural killer (NK) cell enrichment (magnetic bead negative selection). Prolonged time of exposure and increased effector:target ratios revealed marked antitumour activity of PBMC alone. This non-specific immune destruction was enhanced considerably by humanized and rat, but not mouse anti-EGFR mAb. Increased EGFR protein in tumour cells partly correlated with an intensification of ADCC but was accompanied by decreased primary PBMC cytotoxicity. The utilization of PBMC subpopulations suggested a mainly NK-cell-mediated ADCC, which appeared to benefit directly or indirectly, e.g. via the secretion of cytokines, from other PBMC components. In conclusion, humanized (EMD 72000) and rat (ICR 62) anti-EGFR mAb were able to generate strong antitumour ADCC in target monolayers of SCCHN.


Subject(s)
Antibodies, Monoclonal/immunology , Antibodies, Monoclonal/pharmacology , Antibody-Dependent Cell Cytotoxicity/drug effects , Antibody-Dependent Cell Cytotoxicity/immunology , Carcinoma, Squamous Cell/immunology , ErbB Receptors/immunology , Head and Neck Neoplasms/immunology , Carcinoma, Squamous Cell/metabolism , ErbB Receptors/biosynthesis , Head and Neck Neoplasms/metabolism , Humans , Leukocytes, Mononuclear/cytology , Leukocytes, Mononuclear/immunology , Time Factors , Tumor Cells, Cultured
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