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J J Glerum

Publications and source records attributed to J J Glerum.

11 recordsLinked to original sources
PubMed1995

Withdrawal or withholding of treatment at the end of life. Results of a nationwide study.

BACKGROUND: Decisions to withhold or withdraw treatment (nontreatment decisions) become increasingly important because they have to be made more frequently and more explicitly. This nationwide study provides information on the occurrence and background of these nontreatment decisions. METHODS: Three studies were undertaken: interviews with 405 physicians, 5197 answered questionnaires concerning deceased persons, and information about 2257 deaths collected by a prospective study. RESULTS: Of all deaths, 30% appeared to be sudden and unexpected. In 39% of all nonsudden deaths, a nontreatment decision was made. This percentage varied by specialty (28% to 55%). Nontreatment decisions were made more often in older female patients. The decisions were made at the explicit request of the patient (19%), after discussion with the patient or after a previous wish (22%), or without any involvement of the patient (59%). Of this last group, 87% of patients were not competent at the time of the decision. In 24% of cases of nontreatment, life was shortened by at least a week. Of all physicians interviewed, 56% had changed their attitude since the beginning of their practice, most of them toward more nontreatment decisions at the end of life. CONCLUSIONS: Nontreatment decisions are made frequently in medical practice. Most often the physician has to weigh medical and nonmedical burdens and benefits. For this to be done properly, the patient should be involved whenever possible. Other requirements are optimal palliative treatment, better prognostic knowledge, consultation of other specialists, and the absence of defensive motives.

Adolescent↗
PubMed1994

Nationwide study of decisions concerning the end of life in general practice in The Netherlands.

OBJECTIVE: To gain insight into decisions made in general practice about the end of life. DESIGN: Study I: interviews with 405 physicians. Study II: analysis of death certificates with data obtained on 5197 cases in which decisions about the end of life may have been made. Study III: prospective study with doctors from study I: questionnaires used to collect information about 2257 deaths. The information was representative for all deaths in the Netherlands. RESULTS: Over two fifths of all patients in the Netherlands die at home. General practitioners took fewer decisions about the end of life than hospital doctors and doctors in nursing homes (34%, 40%, and 56% of all dying patients, respectively). Specifically, decisions to withhold or withdraw treatment to prolong life were taken less often. Euthanasia or assisted suicide, however, was performed in 3.2% of all deaths in general practice compared with 1.4% in hospital practice. In over half of the cases concerning pain relief or non-treatment general practitioners did not discuss the decision with the patient, mostly because of incapacity of the patient, but in 20% of cases for "paternalistic" reasons. Older general practitioners discussed such decisions less often with their patients. Colleagues were consulted more often if the general practitioner worked in group practice. CONCLUSION: Differences in work situation between general practitioners and hospital doctors and differences between the group of general practitioners contribute to differences in the number and type of decisions about the end of life as well as in the decision making process.

Aged↗
PubMed1990

Mechanical properties of mammalian single smooth muscle cells. III. Passive properties of pig detrusor and human a terme uterus cells.

Cells isolated from pig urinary bladders and pregnant full term human uteruses were attached longitudinally between a microforce transducer and a length displacement apparatus. Cells were stretched by applying a series of ramp-like length changes of 0.2 s duration and 10.0 microns amplitude at intervals of 15 min. Passive forces upon straining were as high as 70-100 microNs. Following these peak forces stress relaxation occurred, levelling off approximately 50% of the maximum peak force. The maximum elastic modulus estimated for single cells was found to be at least a tenfold higher than was previously estimated from intact bladder strips. The relation between the increase in length and the increase in initial force increment was found to be approximately linear. An exponential equation was fitted to a selected number of stress relaxation curves. Relaxation curves of bladder cells show a clearly different time course as compared to bladder tissue strips, suggesting that a significant amount of relaxation in strips has to be contributed to the connective tissue components or to structural changes in these strips.

Animals↗
PubMed1990

Mechanical properties of mammalian single smooth muscle cells. I. A low cost large range microforce transducer.

A transducer has been developed for measuring the minute forces generated during isometric contractions (1.0-10.0 microN) of single smooth muscle cells from the pig urinary bladder and the human uterus. In addition to its high sensitivity, resolution and stability (100 mV microN-1, and less than 0.1 microN and less than 2.0 microN h-1), the transducer features a very wide range (100-140 microN) with good linearity, enabling measurement of contractions as well as passive force-length characteristics within one uninterrupted measurement session. Since the transducer features an independent and interchangeable force to displacement conversion system, different force ranges can be realized by inserting force conversion systems with different compliances.

Animals↗
PubMed1990

Mechanical properties of mammalian single smooth muscle cells. II. Evaluation of a modified technique for attachment of cells to the measurement apparatus.

A method is described for attaching isolated single smooth muscle cells to an apparatus designed for measuring the longitudinal forces developed passively and actively by the cell upon straining, electrical or pharmacological stimulation. Primary attachment of the cell is based on its natural negative surface charge in combination with a positive surface charge on the micro-tools used for attaching. Definite attachment is obtained by a knotting technique. Results show that this method of attachment is reliable and strong enough to withhold forces exceeding those necessary to break or tear the cell. Although this method allows relatively short cells to be attached (L greater than 80 microns). alternative methods e.g. glueing, are necessary to attach the shortest smooth muscle cells.

Animals↗
PubMed1987

Isolation and individual electrical stimulation of single smooth-muscle cells from the urinary bladder of the pig.

In contrast to striated muscle, measurements on strips of smooth muscle cannot be uniquely interpreted in terms of an array of contractile units. Therefore scaling down to the single-cell level is necessary to gain detailed understanding of the contractile process in this type of muscle. The present study describes the development of a method for isolating contractile single smooth muscle cells from pig urinary bladders. Contractile responses evoked by individual electrical stimulation were used as a measure of cell quality during development of the method. Responses were evaluated by measuring latency, contraction and relaxation times, as indicated by visible length changes, and stored on-line in a computer. Initial length, relative shortening and shortening speed were determined by measuring cell lengths in previously timed still video frames using a computer-controlled crosshair device. Increase of stimulus pulse duration resulted in improved responses, indicating that the observed shortening represented a physiological contractile response. Ultimately this method of evaluation was applied to two sets of cell preparations obtained by two different methods, one using only collagenase digestion, the other using mechanical manipulation as well. Both sets showed two main patterns of response to electrical stimulation: a pattern of contraction upon stimulation followed by enhanced contraction when stimulation was switched off (CK), and a pattern of contraction upon stimulation followed by relaxation when the stimulus was switched off (CR). The set of preparations containing the highest percentage of CR cells was found to be superior (i.e. greater initial length, shorter latency and contraction times, increased shortening and higher shortening speed). The method of isolation used for this set gives a high yield of contractile cells available for experimental use over a long span of time.

Animals↗
PubMed1986

Influence of temperature and stimulus interval variations on the propagation of contractions in the pig ureter.

The influences of ureter temperature and time interval between stimulations on the velocity of propagation of contractions in the pig ureter were studied in vitro. The propagation velocity was calculated from electromyogram signals measured at regular distances along the ureter. It was found that a temperature decrease of 3 degrees C causes a velocity decrease of nearly 5 mm/s. The influence of the interstimulus interval is much smaller: a reduction from 300 to 10 s causes a 10% drop in propagation velocity. Both phenomena can be understood from changes in the strength-duration curve describing the excitability of the tissue and clarify the discrepancies between propagation velocity measurements in vitro and in vivo.

Animals↗
PubMed1985

In vitro comparison of isometric and stop-test contractility parameters for the urinary bladder.

Contractility parameters in the urinary bladder can be calculated from isometric contractions (no extra patient load as compared to routine cystometry) or from stop-tests (more accurate, simpler analysis). A stop-test involves a voluntarily interrupted micturition with pressure and flow measurement. In a series of measurements in vitro on pig urinary bladder strips, parameters of the first type, obtained either by analyzing isometric contractions in terms of the Hill model, or by making phase plots, were compared to parameters of the second type. A good correlation was found. Th parameter correlating best with the maximal contraction velocity of the bladder, normalized for differences in initial muscle length, as obtained from stop-test, is the isometric contraction force, which can be obtained from an isometric contraction by either of the two analysis techniques. Clinically, making phase plots seems more promising than analyzing contractions in terms of the Hill model.

Animals↗
PubMed1985

Electrical stimulation of smooth muscle strips from the urinary bladder of the pig.

Strips of smooth muscle from pig urinary bladders were electrically stimulated to contract. Stimulation parameters and conditions were optimized so as to obtain a maximum number of isometric contractions with maximal force. It was found that the contractions could be described mathematically by a simple model. In the model there is a constant probability for cells to pass from the non-contractile to the contractile state during stimulation; this leads to a linearly decreasing phase plot (a plot of the rate of rise of a variable as a function of the variable) for the force. 'Activation' of the cells is described by a physical step function. Isometric contractions were thus characterized by a set of three parameters: U, the time derivative of the force, extrapolated to zero force, Fiso the value of the isometric force which is approached asymptotically after infinitely long periods of stimulation and t1, the activation time. The sensitivity of these three parameters to variation of the stimulus parameters was investigated. It was found that the parameter U was consistently correlated with the stimulus parameters, suggesting that this parameter can be used to describe the effectiveness of electrical stimulation of such strips.

Animals↗