Search PubMed⌕ Search

Biomedical subjects

A Vissink

Publications and source records attributed to A Vissink.

At least 127 records · Page 7Linked to original sources
PubMed1997

[Sjögren's syndrome. Consequences for oral health].

Sjögren's syndrome is an auto-immune disease involving exocrine glands causing amongst others xerostomia and dry eyes. Many other tissues may be affected as well. Early recognition of this disease may help to alleviate signs and symptoms and is, thus, important. The aim of this paper is to provide the dentist with knowledge to enable him to timely diagnose the oral component of Sjögren's syndrome as well as to give guidelines for the treatment.

Diagnosis, Differential↗
PubMed1997

[Changes in secretion and composition of saliva with aging].

About 30% of the elderly suffer from oral dryness and related complaints. Therefore, it is often assumed that salivary secretion reduces with age. Nevertheless, salivary flow rate data in healthy elderly--that are persons without any medication and not suffering from any (treatment related) salivary gland disorder--revealed no significant age-related decrease other than a slight decrease of the secretion from the (sero)mucous glands under conditions of minimal or extended stimulation. No age-related changes were observed in the secretion of parotis saliva. In contrast, some age-related changes occur in the organic composition of saliva. The reported decrease in the concentrations of kallikrein, sIgA, low-molecular mucin and high-molecular mucin might be related to a somewhat decreased immunologic and non-immunologic defense of the oral cavity in the elderly.

Age Factors↗
PubMed1997

[Maxillofacial trauma. How to treat?].

Fractures of the maxillofacial skeleton, often accompanied by dentoalveolar injuries, are no exception. Dentists may become primarily involved in the diagnosis of such a trauma and the treatment of dentoalveolar injuries. More often they will play an important role in the aftercare of such a patient (endodontics, prosthodontics). This paper describes the general principles of the treatment of such patients. The specific treatment of maxillofacial trauma will be described in the contributions of other authors in this special issue.

Humans↗
PubMed1997

[Zygomatic fractures].

The zygomatic bone is important for the midfacial contour and for protection of the orbital contents. Zygomatic fractures frequently occur. Because they are hidden behind a simple black eye in many instances, there is a potential risk of missing the diagnosis. Fresh zygomatic fractures are relatively easy to treat, but late secondary corrections are difficult and often have dissatisfying results. The most important clinical signs of a zygomatic fracture are: flattening of the zygomatic contour, edema, haematoma, unilateral nose-bleeding, disturbed sensibility, diplopia, restricted mandibular movements, contour defects. In this paper the clinical signs of a zygomatic fracture are emphasized to enable the general practitioner to examine the patient with a simple black eye appropriately and be able to recognize a zygomatic fracture.

Diagnosis, Differential↗
PubMed1997

[Fractures of the midface].

Midfacial fractures have a wide variety of appearance. The original classification by Le Fort is still in use. Nasal-orbital-ethmoidal (NOE) fractures deserve special attention. Next to clinical evaluation detailed computer tomography is necessary. Extended open reduction and internal fixation with various mini- and microplate osteosyntheses as well as immediate reconstruction with calvarian bone are essential components of surgical treatment aiming for adequate function and esthetics. Reduction of increased inner intercanthal distances is a substantial part of the treatment of NOE fractures. Surgical repair within 48-72 hours benefits the final result and limits the number and extent of secondary corrections.

Bone Transplantation↗
PubMed1997

Sialogogue-related radioprotection of salivary gland function: the degranulation concept revisited.

To investigate whether secretory granules play a role in the radiosensitivity of the salivary glands of rats, parotid acinar cells, submandibular acinar cells and/or submandibular granular convoluted tubule (GCT) cells were degranulated prior to irradiation. Degranulation of GCT cells was obtained by pretreatment with phenylephrine (5 mg/kg, t = -60 min) and methacholine (3.75 mg/kg, t = -120 min). Degranulation of acinar cells was attained by pretreatment with isoproterenol (5 mg/kg, t = -90 min). Combinations of pretreatments were also tested. Irradiation was performed with a single dose of 15 Gy of X rays. Samples of parotid and submandibular/sublingual saliva were collected 4 days prior to and 1, 3, 6, 10 and 30 days after irradiation. Pretreatment with phenylephrine, isoproterenol and methacholine plus phenylephrine resulted in less radiation damage to parotid gland function as indicated by the lag phase and flow rate. Since the pretreatment with phenylephrine and phenylephrine plus methacholine did not degranulate parotid gland acinar cells, the observed protective effect on this gland cannot be explained by the "degranulation concept." Furthermore, salivary gland function was significantly greater 3 days after irradiation as a result of pretreatment with phenylephrine and phenylephrine plus methacholine compared to rats given only radiation. This may indicate recovery from damage rather than a reduced amount of initial damage. The sparing was most obvious for the later effects (6-30 days). Submandibular/sublingual gland function was improved significantly after pretreatment with methacholine plus phenylephrine, although no increase in degranulation of GCT cells was observed compared to pretreatment with phenylephrine alone, again not favoring the degranulation concept. The results indicate that the secretory granules do not play the often-assumed important role in the radiosensitivity of the salivary gland. The mechanism underlying the observed improvement of salivary gland function may involve second messenger-induced increases in proliferation of salivary gland cells resulting in recovery of tissue after the irradiation.

Animals↗
PubMed1996

Treatment of xerostomia with polymer-based saliva substitutes in patients with Sjögren's syndrome.

OBJECTIVE: To determine the efficacy of 3 types of polymer-based saliva substitutes in reducing oral dryness in patients with Sjögren's syndrome (SS). METHODS: Subjective efficacy of 3 different saliva substitutes (determined by self-administered questionnaire) was evaluated in a double-blind, placebo-controlled trial in 43 patients with primary and secondary SS. High-viscosity versus low-viscosity xanthan gum-based saliva substitutes were also compared in 33 SS patients. Salivary flow rates (SFR) were determined to examine correlations between the SFR and the subjective efficacy of the saliva substitute. RESULTS: Neither the saliva substitutes nor the placebo was truly effective. Preference for a particular saliva substitute over placebo was equally distributed among the 3 types of substitutes. The SFR of patients who preferred polyacrylic acid-based saliva substitutes was lower than that in patients who preferred the porcine mucin-based substitute (P < 0.05). Patients whose oral dryness was reduced by low-viscoelastic substitutes had a low stimulated SFR ( < 0.20 ml/minute; P < 0.05). CONCLUSION: The optimal properties of a saliva substitute are not the same for all patients with SS, but are dependent on such parameters as the individual SFR. Thus, to determine the best saliva substitute for a particular patient, it is necessary to have the patient try a number of substitutes of different viscoelastic properties.

Acrylic Resins↗
PubMed1996

Augmentation of localized defects of the anterior maxillary ridge with autogenous bone before insertion of implants.

PURPOSE: This study evaluated the applicability of intraorally harvested autogenous bone grafts for the augmentation of the narrow maxillary alveolar ridge to enable insertion of implants for single tooth replacement. MATERIALS AND METHODS: Local defects of the anterior maxilla were reconstructed in 27 patients with autogenous bone grafts from the mandibular symphysis (n = 12), maxillary tuberosity (n = 8), or mandibular retromolar area (n = 7). Three months after grafting, either Branemark (n = 23) or ITI Bonefit implants (n = 8) were inserted. RESULTS: At the time of implantation, all grafted sites showed sufficient bone volume for insertion of the implants. Twenty-four to 68 months after insertion, all implants were functioning well. CONCLUSION: Augmentation of local alveolar defects in the maxilla with intraorally harvested autogenous bone grafts appears to be a reliable method to enable implant placement.

Adolescent↗
PubMed1996

Human glandular salivas: their separate collection and analysis.

Human saliva is secreted by the three pairs of major salivary glands (parotid, submandibular, and sublingual), and numerous minor ones, e.g. labial, buccal and (glosso)palatine glands. Using individually adapted collection devices, sublingual, submandibular, parotid and palatine secretions of five individuals were collected and analyzed. Electrophoretic analysis revealed that each type of saliva possesses characteristic features, despite interindividual variations. Parotid salivas are characterized by intensely staining amylase and proline-rich protein bands, but contain minute amounts of cystatins, lysozyme and the extra-parotid glycoprotein. Sublingual salivas are characterized by high concentrations of both types of salivary mucins, MG1 and MG2, and contain relatively high levels of lysozyme. Submandibular salivas contain highest concentration of salivary cystatin S. Palatine secretions contain high molecular weight mucins and a relatively high amylase concentration.

Adult↗
PubMed1995

Use of cultured mucosal grafts to cover defects caused by vestibuloplasty: an in vivo study.

PURPOSE: In oral and maxillofacial surgery palatal mucosal grafts are routinely used to cover mucosal defects caused by vestibuloplasty. However, the quantity of palatal mucosa is a limiting factor in more extensive operations. This study investigated whether autologous cultured sheets of mucosa can serve as a dressing for these wounds. MATERIALS AND METHODS: Punch biopsies (diameter, 4 mm) were taken from the hard palate of eight patients (five men, three women; mean age 43 years). Epithelial cells were enzymatically dissociated from these tissue specimens and grown in vitro in the presence of a fibroblast feeder layer. Within 3 weeks, a transplantable epithelial sheet of about 20 cm2 was obtained. The sheet was detached from the culture flask by enzyme treatment and fixed to a carrier of Vaseline (Cheeseborough Ponds Inc, Greenwich, CT) gauze. Using a split-mouth technique, the sheet was placed on half of a mucosal defect created by vestibuloplasty, while the other half of the defect was covered by a conventional split-thickness palatal graft. Both the cultured and conventional graft were held in place by the patient's relined denture fixed with perimandibular sutures. One week postsurgery, the denture and Vaseline gauze were removed. Three months after vestibuloplasty, biopsy specimens of each grafted site were taken and processed for light and transmission electron microscopy (LM, TEM). RESULTS: Three months postsurgery, the grafted mucosa of both sites bore close resemblance to palatal mucosa. Both the cultured and split-thickness grafts were vascularized, did not evoke a homograft reaction, and showed a smooth graft/lip mucosal junction and minimal wound contraction. LM and TEM revealed that both types of grafts formed a fully differentiated keratinizing mucosa with a well-developed basement membrane and rete ridges, comparable with the histology and ultrastructure of palatal mucosa in situ. CONCLUSION: It was concluded from this study that cultured mucosa can serve as a proper dressing for mucosal defects after vestibuloplasty.

Adult↗
PubMed1995

Degranulation of rat salivary glands following treatment with receptor-selective agonists.

1. The aim of this study was to find a drug that induces an almost complete degranulation of secretory cells in rat parotid and submandibular glands. 2. Phenylephrine (alpha-adrenergic), isoproterenol (beta-adrenergic) and mecholine (muscarinic cholinergic) were tested. Time and degree of maximal depletion of acinar and granular convoluted tubule cells were determined morphologically. 3. Following phenylephrine-injection (5 mg/kg or 10.2 mg/kg, i.p.), no effect on the acinar granulation level was observed in either of the glands, while about 50-60% granular convoluted tubules were degranulated for at least 120-180 min post-injection. 4. With isoproterenol (5, 10, 40, 70 or 100 mg/kg, i.p.), degranulation of 100% of the acinar cells in the parotid and 80% of the acinar cells in the submandibular gland was observed 90 min post-injection. Granular convoluted tubule cells did not respond to this beta-adrenergic drug. 5. Mecholine (3.75 or 7.5 mg/kg, i.p.) induced mainly degranulation of granular convoluted tubule cells (about 50% after 120 min). Numbers of granulated acinar cells decreased only slightly in both glands (about 10%, 90-120 min). 6. From this study it appears that with a relatively low dosage (5 mg/kg, i.p.) of isoproterenol, a high level of degranulation can be induced in acinar cells of rat parotid and submandibular glands without toxic side effects. Concerning granular convoluted tubules, only moderate degranulation was observed with phenylephrine and mecholine, respectively.

Adrenergic alpha-Agonists↗
PubMed1995

[Skin and mucosal grafts. Their place within preprosthetic surgery and implantology].

In preprosthetic surgery, both skin grafts and oral mucosal grafts can serve as a dressing for mucosal defects. Grafts from the palatal mucosa are better suited for reconstruction than skin grafts or oral mucosal grafts with another origin, because palatal grafts lack many of the disadvantages of all other types of grafts. The limitation of palatal mucosa to be used as grafting material is its availability. However, cultured palatal mucosa may offer a solution when large defects have to be covered.

Cells, Cultured↗
PubMed1995

The role of secretory granules in radiation-induced dysfunction of rat salivary glands.

To investigate the possible role of secretory granules in radiation-induced salivary gland dysfunction, rats were pretreated with isoproterenol (5 mg/kg intraperitoneally) to degranulate salivary gland acini. At maximal depletion, salivary glands were locally irradiated with a single dose of 15 Gy of X rays. Parotid and submandibular/sublingual saliva samples were collected before and 1-10 days after irradiation. The lag phase, flow rate, concentrations of potassium and sodium, and amylase secretion were determined. Sham-treated, isoproterenol-treated and irradiated animals provided reference data. In the parotid gland, but not in the submandibular gland, protection against radiation-induced changes in flow rate and composition of saliva occurred after pretreatment with isoproterenol. Combining morphological data from a previous study with data from the current study, it is suggested that improvement of parotid gland function is attributed predominantly to a proliferative stimulus on acinar cells by isoproterenol and not to its degranulation effect. After pretreatment with isoproterenol, an earlier expression of radiation-induced acinar cell damage leading to death was observed, followed by a faster tissue recovery. Thus the proliferative stimulus on acinar cells may accelerate the unmasking of latent lethal damage, resulting in the earlier replacement of dead cells by new, functionally intact cells.

Animals↗
PubMed1994

Radiation-induced cell proliferation in the parotid and submandibular glands of the rat.

Repopulation of tissues with cells at damaged sites is an important feature in the recovery of radiation-induced tissue injury. To obtain insight into the regenerative process in salivary gland tissue, proliferative activity was measured as a function of time in the different epithelial cell compartments of rat parotid and submandibular glands after local X irradiation with a single dose of 15 Gy. Bromodeoxyuridine-labeling indices were determined before and 10 h and 1, 3, 6, 10, 15, 20 and 30 days after irradiation. In both glands, X irradiation caused cell death and cell cycle delay manifested during the first day. Three days after irradiation, cell proliferation started in the intercalated duct. Six days after irradiation, proliferation was also observed in acinar and granular convoluted tubule cells. The striated ducts showed proliferative activity starting at day 6 (parotid) and day 10 (submandibular), respectively. The results of this study suggest that after 15 Gy of X rays repopulation takes place in all cell compartments. From the present study it cannot deduce if these cells are originating solely from progenitor cells residing in the intercalated duct or if cells of the other compartments are also stimulated. Proliferative activity was found to be higher in the intercalated duct compartment of the parotid gland than of the submandibular gland, which may be related to the suggested greater radiosensitivity and thus a greater demand for cell replenishment in the parotid gland.

Animals↗
PubMed1994

The role of secretory granules in the radiosensitivity of rat salivary gland acini--a morphological study.

The aim of this study was to investigate the radiosensitivity of salivary gland tissue pretreated with isoproterenol to establish a status of depletion of secretory granules in acinar cells at the time of irradiation. Nuclear aberrations and cell lysis were taken as parameters for cell death. Local X irradiation with a single dose of 15 Gy induced comparable early morphological changes in the rat parotid and submandibular glands. During the first day after irradiation, the most obvious changes were degranulation of serous cells and induction of nuclear aberrations in both the secretory (serous as well as mucous) and intercalated duct compartment. Subsequently, progressive lysis occurred in secretory units but not in intercalated and striated ducts. Recovery of tissue integrity was observed from day 6. Early radiation-induced cell death was not reduced by isoproterenol-induced degranulation of acinar cells before irradiation. Subsequent recovery from radiation damage seemed to occur earlier in parotid glands but not in submandibular glands pretreated with isoproterenol. From the present study it is concluded that the radiosensitivity of serous salivary gland acini is not dependent on the presence of secretory granules at the time of irradiation. There was some evidence for a faster recovery from radiation damage observed after pretreatment with isoproterenol which may be the result of drug-induced stimulation of cell proliferation.

Animals↗