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Biomedical subjects

M Kroll

Publications and source records attributed to M Kroll.

At least 55 records · Page 3Linked to original sources
PubMed1990

Twenty-four-hour profiles of growth hormone, prolactin and cortisol in the chronic vegetative state.

The 24-h profiles of growth hormone (GH), prolactin (PRL) and cortisol were obtained from 11 patients in the chronic vegetative state in order to gain more insight into the neuroendocrine alterations caused by widespread suprahypothalamic brain damage. Age and sex-matched normal subjects served as a control group. Patients had fewer high-amplitude GH peaks (greater than 20 mU/l: 6 peaks/24 h vs 21 peaks/24-h in controls) and a (non-significant) tendency towards higher basal GH concentrations. PRL concentrations were higher in patients (296 +/- 212 (SD) vs 120 +/- 28 mU/l). Cosinor analysis also showed that 24-h rhythmicity was preserved, but acrophases were more dispersed. A nocturnal PRL acrophase occurred in only three of 11 patients but in 10 of 11 control subjects. The number of PRL peaks was the same in patients and controls. Cortisol concentrations were also higher in patients (298.3 +/- 114.6 vs 193.6 +/- 97.4 nmol/l) with a preserved circadian rhythm. The acrophases, however, were likewise more dispersed. There was no difference in the number of cortisol peaks between patients and controls, but the mean peak duration was shorter in patients (75.4 +/- 28.1 vs 109.5 +/- 28.2 min). The stage of remission was negatively correlated with the 24-h mean and the mean peak amplitude of PRL. No patient showed a normal organization of sleep stages. On visual analysis there was no apparent association between EEG patterns and hormonal parameters. These results suggest that the endocrine hypothalamus is essentially intact in the chronic vegetative state. The observed changes may be due to an altered input from extrahypothalamic brain structures.

Adolescent↗
PubMed1990

Arthrometric evaluation of knees that have a torn anterior cruciate ligament.

We used the KT-1000 arthrometer to test the knees of 107 patients who had an acute tear of the anterior cruciate ligament, 153 patients who had a chronic tear, and 141 control subjects, for a total of 401 individuals. The three testing parameters were the extent of anterior translation at eighty-nine newtons of force and at maximum manual force, and the compliance index. The differences between the involved and the uninvolved knees were calculated. At eighty-nine newtons, all but one of the control subjects had anterior translation of ten millimeters or less, compared with 58 per cent of the patients who had a chronic tear. At maximum manual force, all but two of the control subjects had translation of ten millimeters or less, compared with 20 per cent of the patients who had an acute or a chronic tear. Analysis of variance showed that the clinical diagnosis correlated well with the results for all tests (p less than 0.001). However, when the uninjured knees of patients who had an acute or a chronic tear were compared with the knees of the control subjects, significant differences were noted (p less than 0.001 to 0.006). In the patients who had a chronic tear, there was no relationship between the time from injury to operation and the extent of anterior translation. The arthrometric test at maximum manual force was the strongest discriminant; it differentiated normal from abnormal knees (p less than 0.001) with high sensitivity (92 per cent), high specificity (95 per cent), and high positive predictive accuracy; the cut-off point was eleven millimeters or less.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Malignant fibrous histiocytoma. Prognostic value of the histological findings].

Surgical specimens after excision of malignant fibrous histiocytomas from 41 patients were classified histologically according to subtype; semiquantitatively by cell content, mitosis count, necrosis tendency and cell polymorphism; and "subjective grading". There was no significant difference in survival time between storiform-pleomorphic and myxoid subtypes. The marked scatter in the storiform-pleomorphic subtype reflects the inhomogeneity of this group. Analysis of the individual semiquantitative criteria gave better results. Cases with many mitoses, many necroses, marked cell polymorphism and high cell content had significantly shorter survival times than those with less marked changes. "Subjective grading" was also of prognostic value. However, overlapping of prognostic factors and limitations due to tumour biology allow of only a rough orientating prediction based on histological assessment of malignancy grade.

Histiocytoma, Benign Fibrous↗
PubMed1986

Serum enzyme, myoglobin and muscle strength relationships in polymyositis and dermatomyositis.

Strength of the quadriceps and hamstring groups was biomechanically assessed in terms of isometric torque production in 14 patients with inflammatory myopathy. Eleven had polymyositis and 3, dermatomyositis. Determinations of serum creatine kinase, lactate dehydrogenase, transaminase, and myoglobin were simultaneously obtained over an average period of observation of 1.8 years. In certain individual patients, there were significant correlations between laboratory indices and strength during the entire course of illness. In others, this was not the case. In the total group of patients, absolute values of the laboratory indices did not correlate well with strength except in the case of serum myoglobin, where there a significant inverse relationship. Logarithmic transformations of the laboratory data increased the inverse correlations. High strength and low myoglobin were related to high prednisone dose. Since laboratory guides are not always related to disease activity, quantitative assessment of muscle strength is necessary.

Adult↗
PubMed1983

Dissociation of light onset and wake onset: effect on rhesus monkey growth hormone secretion.

Synchronization of GH-secretory episodes occurs at light onset in the rhesus monkey and is later lost during the 24-h day. The stimulus for this synchronization was studied in nine male adult monkeys prepared with chronic jugular catheters. In a first experiment, light onset was delayed by 2 h (from 0600 to 0800 h) on days 2-6 and returned to 0600 h on day 7. The animals were allowed to sleep on during the additional time of darkness. The early morning GH peak was immediately shifted to the new light-onset times, both after introduction of the delay and after its reversal. In a second experiment, the animals were awakened in darkness during a similar light-onset delay. Now the GH peaks constantly occurred at the time of awakening shortly after 0600 h, and no GH peak was seen after light onset at 0800 h. Neither experimental condition had an influence on the patterns of plasma PRL and cortisol. These results suggest that the early morning synchronization of the GH-secretory pattern in the rhesus monkey is triggered by awakening and not by light onset.

Animals↗
PubMed1975

Poly(A) polymerase in quail oviduct. Changes during estrogen induction.

A nuclear poly(A) polymerase has been isolated from oviducts of immature quails. It could be purified 4300-fold. The enzyme depends specifically on ATP as substrate and requires Mg2+. The most effective primer for the enzyme is a polynucleotide, isolated from oviduct tissue. A poly(A) sequence to a maximum of 60 AMP residues is covalently linked per primer molecule. The poly(A)-rich product of the enzymatic reaction can be annealed to oligo(dT)-cellulose. The purest fraction does not contain any detectable poly(A)-degrading enzyme activity. Only very low activities of RNA polymerase are present. The poly(A polymerase activity in the assay with ATP is reduced by the ATP analogue, beta, lambda-ATP-methylene-diphosphonate. Both K-m and V are lowered. The ATP analogue is incorporated to a smaller extent into the poly(A) sequence, synthesized by the enzyme. Several other analogues of adenine, adenine nucleosides and adenine nucleotides are without effect on the enzymatic reaction. By these properties poly(A) polymerase can be distinguished from RNA polymerases form I and form II, isolated from the same tissue. Actinomycin D and alpha-amanitin failed to inhibit poly(A) polymerase activity. The activity of poly(A) polymerase has been determined during primary stimulation with the estrogen analogue diethylstilbestrol (daily injection for 5 days), after withdrawal of the hormone for 17 days and after secondary stimulation with the hormone analogue. The enzyme activity does not change during primary stimulation, withdrawal of the hormone or secondary stimulation. However the activity of a poly(A) degrading enzyme, localized in the nucleus, is reduced in oviducts from hormone-treated quails.

Adenine Nucleotides↗
PubMedDate not supplied

Torque-velocity relationships of the knee extensor and flexor muscles in individuals sustaining injuries of the anterior cruciate ligament.

Muscle deficits in 58 patients with chronic anterior cruciate ligament (ACL) insufficiency were evaluated after completion of a 6 month rehabilitation program. Quadriceps and hamstring torques were measured on a modified Cybex II isokinetic dynamometer. Twenty-nine of our patients were tested just prior to undergoing ACL reconstruction, and patients who were continuing to tolerate their conditions served as controls. For the surgical group, significant quadriceps deficits (P less than 0.01) were found for all speeds and at both the 30 and 60 degrees positions. The nonsurgical group had significant deficits at the 30 degrees position at 180 degrees/sec, and at 60 degrees for the 0 degree/sec and 30 degrees/sec. However, in comparing the two groups no significant differences were noted. Regarding hamstring deficits in the surgical group, significant deficits were seen only at 30 degrees of flexion at 180 degrees/sec. The nonsurgical group had similar deficits. Of interest was the observation that the hamstring:quadriceps (H:Q) ratio was found to be both speed-position dependent. Overall, no correlation was found between the presence of strength deficits following a rehabilitation program and the need for surgery.

Adolescent↗
PubMedDate not supplied

Managing the climacteric.

HRT taken for a sufficient duration may reduce the occurrence of osteoporosis and of cardiovascular disease by up to 50% and possibly also reduce incidence and lessen severity of Alzheimer's disease. Nevertheless, it is often only prescribed when women request it to relieve climacteric symptoms. Furthermore, many physicians prescribe it for only limited periods of time and few are willing to prescribe it to women in their sixties. As with any long-term prevention strategy, the uptake of HRT is much lower than the prescription rate, since the medication is often abandoned due to side effects or due to lack of motivation. But HRT is often abandoned also due to fear of cancer. While physicians may be aware of some beneficial effects of HRT, they often have no time to inform their patients of them. Alternatively, some of the beneficial effects such as cardioprotection or a reduced incidence of Alzheimer's may be less known. Likewise, HRT-related side effects or risks such as breast cancer or thromboembolic diseases should be discussed prior to HRT prescription. Women need to be informed about these potential risks, and this should be done by their physician. Surveys have shown that many women feel that they receive insufficient information from their physician. The quality of the relationship between physician and patient probably has a large influence on HRT acceptance, but very few studies have been conducted to assess specifically factors influencing the prescription and the continuation rate of HRT. Simple strategies may be among the most effective ones; these include listening to patients' fears, complaints and questions, and taking the time to answer them. The role of a practice nurse in such a setting may be also very important.

Attitude to Health↗