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Biomedical subjects

C Blok

Publications and source records attributed to C Blok.

At least 19 recordsLinked to original sources
PubMed2004

Generic computer-based questionnaires: an extension to OpenSDE.

Development of computer-based questionnaires (CQs) has been an ongoing challenge since the 1960s. The added value of such CQs for data collection and the acceptance by patients have been well documented. Many questionnaire projects, however, were temporary due to dedicated software, limited funding, and lack of integration with medical information systems. Also, the use of a fixed dedicated database makes integration cumbersome, as change in content requires change to the data model. Since much of the functional requirement of CQs is not dependent on content, the challenge is to both separate functionality and database structure from content. Following these principles, we extended OpenSDE, a generic application for structured data entry, with a tool to construct and run CQs as an alternative way of data input. We propose the combination of a generic building tool and a content-independent data model as an effective strategy to tackle the above-mentioned problems in CQ development.

Data Collection↗
PubMed1999

[Missed infections in immigrant children].

Three African children who migrated to the Netherlands developed serious infections after they arrived. The first patient, a girl of 3 years adopted from the Zaire, was discovered to be a chronic hepatitis B carrier. Advice to vaccinate her whole adoption family was not followed. Her adoptive mother became infected with hepatitis B. The second patient, an Ethiopian girl of 13 years, was not adequately screened for infections on arrival. She was a chronic hepatitis B carrier and infected her adoptive mother. Seven years later she developed pulmonary tuberculosis with cavity formation and infected four contacts. The third patient, a 15-year-old political refugee from Zaire, who developed paediatric aids and later died of it, was not screened according to the screening protocol advised for immigrating children. All immigrating children should be fully and adequately screened for infectious diseases upon arrival in the Netherlands.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Glass ionomers--types and clinical application].

With the formation of the glassionomers one wanted to combine the major qualities of the silicate cement, the composite resins and the polycarboxylate cement. The greatest advantages are bonding to tooth structure, the release of fluorides and thereby an inhibition of secondary caries, and a thermal coefficient similar to tooth structure. The glassionomers are more compatible to the pulp than the old silicates. The bonding to tooth structure is increased through pretreatment where polyacrylic acid is most recommendable. Today there are two major types of glassionomers: the water-based which contain freeze-dried acid in the glass powder, and the original, determined by the addition of an aqueous solution of polyacrylic acid to the glass powder. Certain types are delivered in premeasured capsules for mechanical blend, which decreases the sensitive handling of the material. The use of glassionomers serves a number of purposes and will properly be more widespread in the future, especially the concern of lining in combination with composite resins, the metal-reinforced to crown-buildup and the luting types, when the considerations about earlier hypersensitivity after luting of castings is clarified. The restorative types shows better promising results than composite resins in Class V restoration.

Dental Bonding↗
PubMed1986

Dynamics of the ureterovesical junction: interaction between diuresis and detrusor instability at the ureterovesical junction in pigs.

In pigs under general anesthesia, the mutual relation between ureterovesical flow and detrusor activity was evaluated with juxtavesical ureteral perfusion pressure measurements and cystometry. At constant bladder filling volume ureterovesical perfusion could provoke detrusor activity, which was positively related to the perfusion rate, and which disappeared after perfusion was stopped. During such involuntary detrusor activity ureterovesical perfusion pressure might increase significantly more than intravesical pressure. It is concluded that ureterovesical flow causes distension of detrusor muscle bundles around the ureteric hiatus, which may trigger local and general detrusor activity in an unstable bladder. During such detrusor activity, due to forces in the bladder wall, resistance to outflow from the upper urinary tract could be significantly more impaired than is reflected by the increase of intravesical pressure at cystometry. The clinical implications are discussed.

Animals↗
PubMed1986

Dynamics of the ureterovesical junction: its resistance to upper urinary tract outflow in pigs.

In pigs, upper urinary tract outflow resistance at the ureterovesical junction (UVJ) has been investigated before and after changes of capacity and compliance of the bladder with ureterovesical perfusion pressure (UV-PP) measurements and cystometry (PB). Changes of UV-PP approximately paralleled changes of PB during volume changes and compression of the bladder, and during detrusor activity. Exceptions were: detrusor activity in all bladders, being nondistended, during which UV-PP always increased more than PB; and low and high compliant, and small capacity bladders in which UV-PP may change more than PB under all conditions once these bladders are so far filled that they are distended. From these findings and UVJ anatomy it is concluded that, besides intravesical pressure, anatomical factors and forces in the bladder wall also may determine upper urinary tract outflow resistance. The clinical implications are discussed.

Animals↗
PubMed1985

Dynamics of the ureterovesical junction: its fluid transport mechanism in the pig.

The peristaltic fluid transport mechanism of the ureterovesical junction was investigated with distal and juxtavesical ureteral perfusion pressure measurements. Elimination of the activity of the juxtavesical ureteral segment, juxtavesical or intravesical partial resection of the ureteral sheaths, and impediment of shortening of the muscular layers of the ureterovesical junction ureter segment, all reduced the effectiveness of ureterovesical junction peristalsis. From these findings and from the anatomy of the ureterovesical junction we concluded that peristaltic urine transport through the ureterovesical junction is effectuated by shortening and telescoping of the muscular layers of the ureterovesical junction ureter segment and its sheaths into each other and into the ureteric hiatus.

Animals↗
PubMed1985

Relative urethral leakage pressure versus maximum urethral closure pressure. The reliability of the measurement of urethral competence with the new tube-foil sleeve catheter in patients.

In 78 female patients the urethral leakage pressure, defined as the intravesical pressure at which leakage starts from the urethral orifice, was estimated with the tube-foil sleeve catheter. In accordance with the definition of maximum urethral closure pressure, the relative urethral leakage pressure was defined as urethral leakage pressure minus intravesical resting pressure. In the same patients urethral closure pressure was also measured by urethral pressure profilometry with a flexible micro pressure-sensor catheter. On the average the ratio of relative urethral leakage pressure/urethral closure pressure was about 0.5. Relative urethral leakage pressure and urethral closure pressure were higher than the maximum detrusor pressure increases during detrusor instabilities in 21 continent patients with motor urge. The relative urethral leakage pressure correlated better with the detrusor pressure elevations at which fluid loss from the urethral orifice started in 24 motor urge incontinent patients than urethral closure pressure did.

Female↗
PubMed1985

Dynamics of the ureterovesical junction; a qualitative analysis of the ureterovesical pressure profile in the pig.

In pigs, ureterovesical pressure profiles were analyzed by combined prevesical perfusion pressure measurement and microsensor pressure profilometry of the ureterovesical junction, which showed comparable and reproducible fast and slow pressure waves. Cystoscopy revealed that the fast pressure waves were associated with fluid spurts from the ureteral orifice and wrinkling of bladder mucosa over the ureterovesical junction. During slow pressure waves only initial decreases in outflow from the orifice may occur. After dissection of the detrusor muscle at the UVJ only fast pressure waves were recorded. At similar pressure measurements on an inactivated ureter segment which was obliquely passed through the bladder wall only slow pressure waves could be detected. It is concluded that the fast pressure waves of the ureterovesical pressure profile represent peristaltic activity which is generated at the ureterovesical junction and by which fluid may be discharged into the bladder. The slow pressure waves of the pressure profile reflect impairment of flow through the ureterovesical junction by detrusor activity.

Animals↗
PubMed1985

Dynamics of the ureterovesical junction; effectiveness of its ureteral peristalsis in high pressure pig bladders.

In pigs, the effectiveness of ureteral peristaltic fluid discharge from the ureterovesical junction at high intravesical pressures was evaluated by ureterovesical perfusion pressure (UVPP) measurements and continuous endoscopic observation of the ureteral orifice during cystometry. Basal UVPPs either remained low, or were elevated but then intermittently could be reduced to near pre-bladder-filling levels at the end of the peristaltic pressure waves during which fluid was discharged from the ureteral orifice. Reductions of elevated basal UVPP correlated with the volumes of the associated discharged fluid boluses and with the perfusion times until such decreased basal UVPP again reached the elevated level it had before the peristaltic pressure waves. Even an elevated juxtavesical basal ureteral pressure which was already well below high intravesical pressure could be further reduced to near normal level after a ureteral peristaltic contraction which was accompanied by fluid discharge from the ureteral orifice. The clinical implications of these findings are discussed.

Animals↗