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Biomedical subjects

A J Schmidt

Publications and source records attributed to A J Schmidt.

At least 37 records · Page 2Linked to original sources
PubMed1987

Psychological research and chronic low back pain: a stand-still or breakthrough?

Some of the main psychological research topics concerning chronic low back pain (CLBP) are critically discussed. These topics include: 1. research aimed at describing a specific low back pain personality profile, 2. research into the predictability of therapy results on the basis of psychological assessment, and 3. outcome research of psychologically-oriented treatment for CLBP. It is concluded that these topics provide little insight into the role of psychological factors in the development and maintenance of CLBP. Based on the few empirical studies available, some new and promising directions for future research are proposed, aimed at gaining a better insight into the CLBP syndrome itself. Discussed are: 1. Risk factors in the transition from acute to chronic LBP, 2. the deviant sensitivity to acute, experimental pain stimuli of CLBP patients, 3. the relationship between CLBP behavior and psychophysiologic variables, 4. determinants of CLBP behavior, with special attention to endurance, 5. the deviant processing of proprioceptive stimuli, and 6. the implementation for chronic pain of the unpredictability and uncontrollability paradigms. The emphasis in the presentation of these new topics is more on raising questions than on answering them.

Back Pain↗
PubMed1986

Persistence behavior of chronic low back pain patients in an acute pain situation.

The test behavior of 24 chronic low back pain patients was compared with the behavior of 24 healthy control Ss., matched for age and sex, in an experimental, acute pain situation (cold pressor-test). Chronic low back pain patients showed poorer persistence behavior and reported more pain. Thus, elements of typical chronic low back pain behavior were also present in an acute pain situation. These findings are discussed within the framework of stimulus-generalization theory. In addition, the effect of different coping strategies on pain tolerance was reconfirmed. The chronic low back pain group and the control group did not cope differently.

Acute Disease↗
PubMed1985

Cognitive factors in the performance level of chronic low back pain patients.

An experimental group of 39 chronic low back pain (CLBP) patients and an equal number of controls, matched for age and sex, completed questionnaires of self-concept and performance motivation. SS were also tested on a standardized back-stress physical test carried out with low external information and feedback. The results revealed a strong tendency for CLBP patients to have a negative self-concept, confirming the findings of previous research. Poorer performance of the CLBP patients on the physical test measure of behavioural persistence and on physiological measures were unrelated to reported pain level or to poor physical condition. Compared to the controls, the chronic low back pain group was less able to estimate their physiological level of exertion, being inclined to overrate their actual individual effort. The interaction of a negative self-concept and negative expectations is discussed.

Achievement↗
PubMed1985

Performance level of chronic low back pain patients in different treadmill test conditions.

An experimental group of 39 chronic low back pain (CLBP) patients and an equal number of control subjects matched for age and sex were tested with a standardized back stress physical test. The subjects were given no indication of the performance expected and no feedback was given during the test. The test was repeated with a high frame of reference and feedback offered to the subjects. In the latter condition the control group improved their performance in contrast to the CLBP group. The poorer performance of the CLBP patients in both conditions was unrelated to pain increase, post-test pain level or poor physical condition. However, there is a clear relationship between performance and pre-test pain level, especially in the feedback condition. In this condition, it also seems that increasing pain level during the test is used as a 'rationalization' for the built-in failure experience. Compared to the control group the CLBP patients were less able to estimate their physiological level of exertion and were inclined to overrate their actual effort.

Adult↗
PubMed1975

Localization of 5'-ribonucleotide phosphohydrolase in regenerating (and normal) limb tissues of the adult newt Notophthalmus viridescens.

The regenerating forelimb of the adult newt, Notophthalmus viridescens was investigated for 5'-nucleotidase (5' ribonucleotide phosphohydrolase, 3.1.3.5) acitivity. The newt's humeri were surgically removed, and after a twenty-one-day recovery period, the forelimbs amputated above the elbows. Regenerates were sampled at predetermined times for specific phases in the progress of regeneration, frozen, sectioned in a cryostat, and the sections fixed in 10% cold formol calcium. The Wachstein and Meisel [25] lead procedure at neutral pH was used predominately in these experiments, although tests were also conducted with Gomori's [14] calcium, Allen's [21] highly alkaline procedures. The substrates used to obtain specific enzyme reactions were adenine, cytosine, guanine, uracil and inosine 5'-monophosphate nucleotides. Sodium beta-glycerophosphate served as a non-specific phosphomonoesterase substrate, distilled water replaced substrate, and inhibitors such as zinc and cyanide ions were used as control measures to assist in increasing the precision in interpreting the results obtained. The most reactive 5'-nucleotidase (5'-Nase) loci were in the walls of the blood vascular system, mysial and neural sheaths, dermis, and periosteum: the principal cells involved were macrophages, endothelium of blood vessels, and fibrocytes of connective tissues. A moderate enzyme response was elicited from secretory cells of some of the subcutaneous glands, hypertrophied chondrocytes and osteogenic centers, chondrocytes in the articular regions and within red blood cells and leucocytes. Normal, injured and degenerating, or regenerating striated muscle and nerve fibers were judged unreactive for 5'-Nase. The epidermis and wound epithelium displayed negative responses for 5'-Nase. Cells forming the regeneration blastema were 5'-Nase reactive during the early formative phase, but with growth and development of the blastema into bulb and conic forms, these cells did not respond for this enzyme-activity. One suggestion offered is that the absence of 5'-Nase in cells of the blastema may be related to the lack of an adequate blood-vascular supply. Several functions of 5'-Nase in normal and regenerating tissues are discussed. A basic conclusion reached is that 5'-nucleotidase hydrolyses may be more involved in fundamental anabolic than in catabolic metabolism.

Adenine Nucleotides↗
PubMedDate not supplied

Bottlenecks in the diagnosis of hypochondriasis.

This review deals with diagnostic problems in DSM-III-R hypochondriasis. A first category of problems is directly connected with the definition of hypochondriasis. The following topics are discussed: the distinction between hypochondriasis and hypochondriacal attitude, the personality aspects of hypochondriasis, and the role of medical findings in the diagnosis. This is followed by a discussion of problems as to the distinction between hypochondriasis and related disorders. This concerns the status of hypochondriasis as a primary or secondary disorder in depression and the relationship with anxiety disorders (especially panic disorder and obsessive-compulsive disorder [OCD]) and the somatization disorder. The DSM-III-R classification of hypochondriasis as a somatoform disorder is disputed. A third category of problems lies in the measurement of hypochondriasis. The scope and quality of the most frequently used questionnaires for measuring hypochondriasis are poor. In research, on the basis of a single questionnaire and without due consideration of medical findings, the diagnosis of hypochondriasis is applied too soon. Finally, it is briefly indicated that the lack of diagnostic clarity affects the way in which the patient is approached in clinical practice.

Depressive Disorder↗
PubMedDate not supplied

Suggestibility in hypochondriacal patients and healthy control subjects. An experimental case-control study.

This study examined suggestibility to bodily sensations in hypochondriacal patients and healthy subjects. Both groups participated in an experiment in which electrical current was announced but not delivered. Suggestibility was measured by the number of responses and by response latencies. The authors hypothesized that the hypochondriacal patients would be more easily influenced by the expectation of a forthcoming stimulus, leading to higher and quicker "stimulus detection" rates than those experienced by the healthy subjects. In contrast to these expectations, the healthy subjects showed higher response frequencies and lower response latencies. Thus, the hypochondriacal patients appeared to be less influenced by the expectation that was raised. The theoretical and clinical implications of the results are discussed.

Adult↗
PubMedDate not supplied

Diagnostic yield of MR-guided liver biopsies compared with CT- and US-guided liver biopsies.

PURPOSE: To compare diagnostic yield and complication rates of magnetic resonance (MR)-guided versus computed tomography (CT)- and ultrasound (US)-guided liver biopsies. MATERIALS AND METHODS: MR-, CT-, and US-guided liver biopsies performed between 9/96 and 9/98 were compared. Sixty patients (21 men and 39 women, mean age 60 years) underwent MR-guided biopsy of liver lesions. Thirty patients (16 men and 14 women, mean age 59 years) underwent CT-guided biopsy. Eighteen patients (seven men and 11 women, mean age 50 years) underwent US-guided biopsy. MR procedures were performed in an open-configuration 0.5-T Signa SP MR unit. Lesion localization used standard T1 and T2 sequences, whereas biopsies were performed with multiplanar spoiled gradient recalled echo and fast gradient recalled echo sequences. A coaxial system with an MR-compatible 18-gauge stabilizing needle and a 21-gauge aspiration needle was used to obtain all samples. In CT and US procedures, a 19-gauge stabilizing needle and a 21-gauge aspiration or a 20-gauge core biopsy needle were used. A cytotechnologist was present to determine the adequacy of samples. RESULTS: MR had a diagnostic yield of 61%. CT and US had diagnostic yields of 67% and 61%, respectively. No serious complications were reported for MR and US procedures. Two CT biopsies resulted in postprocedural hemorrhage. One patient required surgical exploration and died. CONCLUSIONS: MR-guided biopsy of liver lesions with use of a 0.5-T open-configuration magnet is safe and accurate when compared with CT and US. No statistical difference was observed between the diagnostic yield of biopsies performed with MR, CT, and US guidance. MR enabled biopsy of a number of lesions in the hepatic dome and lesions with low contrast, which would normally be difficult to sample safely with use of CT or US.

Biopsy, Needle↗