[Peptide-producing tumors in the pancreas and gastrointestinal tract: syndrome, survey, therapy].
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Carcinoid Tumor↗
Biomedical subjects
H Johansson
Publications and source records attributed to H Johansson.
Measurement of nuclear DNA content in thyroid diagnosis.
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Adenocarcinoma↗
Ultrasonic localization and cytologic identification of parathyroid tumors.
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Adenoma↗
Fusimotor reflexes in triceps surae muscle elicited by extension of the contralateral hind limb in the cat.
Experiments were performed in thirty-two cats anaesthetized with chloralose. The aim of the study was to investigate the reflex effects of flexion or extension of the contralateral hind limb on ipsilateral fusimotor neurones, to compare these effects with the effects elicited by stretch of the ipsilateral posterior biceps and semitendinosus (p.b.s.t.) muscles (Appelberg, Hulliger, Johansson & Sojka, 1982) and to clarify the interactions between the reflexes elicited from the ipsilateral and the contralateral side. Activity in fusimotor neurones was studied indirectly by recording from primary and secondary muscle spindle afferents of the triceps surae muscle. The mean rate of firing and the modulation of the afferent response to sinusoidal extension of the triceps surae was determined. Control measurements were made with the ipsilateral p.b.s.t. muscles relaxed and the contralateral hind limb in resting position. Tests were made with stretch of the ipsilateral p.b.s.t. and/or extension/flexion of the contralateral hind limb. With extension of the contralateral hind limb 64 out of 210 primary afferents (30.5%) showed predominantly dynamic reflexes (41 out of 134 in spinalized preparations: 30.6%), 25 (11.9%) showed mixed or predominantly static effects (1 spinalized: 0.7%), 121 (57.6%) showed no effect (92 spinalized: 68.7%). Flexion of the limb gave, with only two exceptions, no observable effect. Thirty-three secondary afferents were investigated. Five responded to extension of the contralateral hind limb with excitatory reflex effects. Flexion did not influence the secondary afferents. Mostly the reflex effects were not accompanied by detectable electromyogram (e.m.g.) activity in the ipsilateral triceps (surface recordings), indicating that the reflexes mainly involved gamma-motoneurones. A comparison was made between the reflexes elicited by stretch of the ipsilateral p.b.s.t. and extension of the contralateral hind limb. The percentage of responsive units was higher for the contralateral stimulus. Spinalization almost abolished the statis reflex responses to both ipsi- and contralateral stimulation, and it increased the number of dynamic responses to ipsilateral stimulation. The ipsilaterally elicited reflexes also seemed more dependent upon background activity. Ipsilateral stimulus could facilitate or reduce a contralaterally evoked response, even when the ipsilateral stimulus alone gave no effect. The reflexes could also summate. Quite often combined stimuli changed the character of the reflex from dynamic to static or vice versa.(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
Ultrasonic appearance of adenomatous and hyperplastic parathyroid glands.
An investigation was made of the sonographic and histopathologic characteristics of 27 parathyroid adenomas and 11 primary and secondary hyperplastic parathyroid glands demonstrated by ultrasound before surgical confirmation. All the hyperplastic glands and 21 of the adenomas had a homogeneously sonolucent interior structure and a smooth periphery. The adenomas and hyperplastic glands were sonographically indistinguishable except for 5 large adenomas which had areas of varying echodensity and an irregularly nodulated periphery. The ultrasonically inhomogeneous adenomas were histopathologically more heterogeneous with asymmetric, nodular enlargement. One patient had a cystic adenoma. The results are discussed in relation to the ultrasonic appearance of thyroid noduli and lymph nodes being the main source of errors in parathyroid ultrasonography.
Adenoma↗
Effects of 1,25- and 24,25-dihydroxycholecalciferol on parathyroid hormone release from human parathyroid cells in vitro.
The effects of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) on parathyroid hormone (PTH) release from human parathyroid cells were investigated using an in vitro system of dispersed cells. The cells were obtained from 7 patients with primary hyperparathyroidism (HPT) and adenoma, 4 patients with primary HPT due to hyperplasia and 2 patients with parathyroid hyperplasia secondary to chronic renal failure. The dispersed cells were incubated in tissue culture medium at low, normal and high external calcium concentrations for 2-16 h. There was a gradual suppression of PTH release (5-55%) when the calcium concentration in the medium was increased from 0.5 to 3.0 mM, thus indicating retained regulation of hormone release. The addition of 1,25-(OH)2D3 in concentrations of 0.1 and 1 ng/ml and of 24,25-(OH)2D3 in concentrations of 1.0 and 10 ng/ml during the incubations did not further affect the amount of PTH released by the cells. The concentrations of the different vitamin D metabolites tested closely correspond to levels observed under normal physiological conditions and during treatment with high doses of vitamin D in vivo. Thus, the findings contradict the idea of any direct short-term regulatory effect of either 1,25-(OH)2D3 or 24,25-(OH)2D3 on the secretion of PTH from hyperfunctioning human parathyroid tissue.
24,25-Dihydroxyvitamin D 3↗
Arterial calcifications in uraemic rats treated with 1-alpha-hydroxycholecalciferol and parathyroidectomy.
The effect of 1-alpha-hydroxycholecalciferol (1-alpha-OH-D3) on the incidence of arterial calcifications, and the influence of parathyroidectomy on the effect of this vitamin D treatment, were studied in uraemic rats. Uraemia was induced by 3/4 kidney resection, and parathyroidectomy was achieved by electrocoagulation. 1-alpha-OH-D3 in a dose of 3, 10 or 125 ng/100 g body weight (b.w.) was given in the drinking water. The animals were killed after 12 or 16 weeks. Aorta and small arteries in the heart and in anterior tibial muscle were studied by light microscopy. Arterial lesions were frequently found in uraemic rats and were characterized by medial necrosis and calcifications. Following a 1-alpha-OH-D3 dose of 125 ng/100 g b.w. in uraemic rats both serum calcium and serum phosphate were increased and there was a high incidence of arterial calcifications both in the aorta and the small arteries. In uraemic rats receiving 10 ng/100 g b.w. of 1-alpha-OH-D3 serum calcium was only slightly elevated although the incidence of arterial calcifications (mainly in the aorta) was such higher than in uraemic rats without vitamin-D treatment. A dose of 3 ng/100 g b.w. of 1-alpha-OH-D3 given to uraemic rats did not result in any serum calcium increase, nor did it alter the incidence of arterial calcifications. Parathyroidectomy prevented arterial calcifications. Parathyroidectomy prevented arterial calcification in uraemic rats, but this effect was abolished by 1-alpha-OH-D3 in a dose of 10 ng/100 g b.w. which only raised the serum calcium to a subnormal value. In uraemia, treatment with 1-alpha-OH-D3 may increase the serum calcium X phosphate product, but this cannot fully explain the increased incidence of arterial calcifications. It is therefore suggested that vitamin D causes changes in the arterial wall which increase its susceptibility to the development of calcifications.
Animals↗
The aortic content of glycosaminoglycans, hydroxyproline and calcium in experimental uraemia with special reference to parathyroidectomy and vitamin-D treatment.
The contents of the various glycosaminoglycan (GAG) fractions, hydroxyproline and calcium in the thoracic aorta from the rat were studied. The effect on these contents of induced uraemia (3/4 kidney resection) combined with parathyroidectomy and/or 1-alpha-hydroxycholecalciferol (1-alpha-OH-D3) treatment was evaluated. Confirming earlier results increased levels of GAGs (predominately of chondroitin and dermatan sulphate) were found in the aortae of uraemic rats. The present study showed that parathyroidectomy or treatment with 1-alpha-OH-D3 did not significantly further alter the aortic content of GAGs in uraemic rats. Arteriosclerotic changes (calcifying medial necrosis) were only found in non-parathyroidectomized uraemic rats given 1-alpha-OH-D3. The aorta from these rats had a lower total content of GAGs, mainly due to a decrease in hyaluronic acid, than that from uraemic rats without calcifications. The aortic content of calcium was lowest in uraemic parathyroidectomized rats. Treatment with 1-alpha-OH-D3 increased this content, which was augmented 100-200-fold when calcifications were present. No correlation between the aortic contents of calcium and GAGs was found. There was a statistically significant correlation between the aortic content of calcium and the serum calcium X phosphate product. A significantly lower content of hydroxyproline was found in uraemic non-parathyroidectomized rats given 1-alpha-OH-D3, especially in those with arteriosclerosis.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Parathyroid pathology in hyperparathyroidism secondary to chronic renal failure.
Weights and histopathological changes in parathyroid glands were evaluated in relation to clinical and biochemical parameters in 42 patients who underwent parathyroidectomy for hyperparathyroidism (HPT) secondary to chronic renal failure. There was a positive relation (r = 0.71, p less than 0.01) between duration of renal insufficiency and total parathyroid glandular weight. The glandular weight was also closely related to the serum levels of parathyroid hormone (r = 0.67, p less than 0.01). No correlation was found between total parathyroid glandular weight or histopathological findings and clinical symptoms, serum levels of calcium, phosphate, alkaline phosphatases, calcium X phosphorus product or radiological evidence of bone disease. The enlargement of the glands was mostly uniform in the individual patient and all patients showed multiple gland involvement. This indicates that when parathyroid surgery is performed in patients with uraemia and secondary HPT, a radical approach, i.e. total parathyroidectomy with autotransplantation or subtotal parathyroidectomy, should always be used. In smaller glands only diffuse hyperplasia of parenchymal cells was generally found; fat cells were present in near-normal amounts. With increasing glandular weight, fat cells were more sparse and nodularity was common. In general, the proportion of oxyphil cells increased parallel with the total glandular weight, suggesting that this cell type is sensitive to stimulation. As a group, patients undergoing conservative renal treatment had suffered longer with renal disease, had larger parathyroid glands with more nodularity, and had more oxyphil cells than those undergoing parathyroidectomy while on haemodialysis.
Adolescent↗
Ultrasound scanning for preoperative location of parathyroid tumours.
Ultrasonic examination of the parathyroid glands has been used in 50 consecutive patients with surgically verified hyperparathyroidism. It revealed 21 of 32 parathyroid adenomas located in the neck. In 16 patients with primary or secondary (uraemic) hyperplasia, 11 out of 48 hyperplastic glands in the neck were identified by ultrasound. A parathyroid adenoma was revealed in all (3) patients with hypercalcaemic crisis. Enlarged parathyroid glands were correctly located in all (5) patients with adenomas and previous explorations of the neck, whereas two out of three glands were visualized by ultrasound prior to secondary explorations in 3 patients with hyperplasia associated with the multiple endocrine neoplasia syndrome type 1. Undetected parathyroid glands were generally smaller than those visualized by ultrasonic examination. It was often difficult to unequivocally establish that identified lesions represented parathyroid glands. Irregular noduli and cysts of the thyroid as well as lymph nodes could be misinterpreted as parathyroid lesions. A nodular thyroid goitre was present in almost half of the patients with a negative ultrasonic examination of the parathyroid glands.
Adenoma↗
Enterochromaffin cells in the rat gastrointestinal tract after vagotomy.
The effect of vagotomy on the enterochromaffin (argentaffin) cells in the rat gastrointestinal tract was studied 6 weeks after the operation. No effect was found, as indicated by the following parameters--the frequency of the silver-positive cells in different parts of the digestive tract, the intensity of the argentaffin reaction in the individual cells, and the nuclear size of the enterochromaffin cells.
Animals↗
Alveolar stability during anaesthesia for reconstructive vascular surgery in the leg.
Alveolar stability was studied during prolonged enflurane anaesthesia by using a multiple inert-gas elimination technique for the assessment of the "continuous" distribution of ventilation-perfusion ratios (VA/Q). All 10 patients (mean age: 61 years, six smokers) presented with increased VA/Q mismatching during anaesthesia, with a redistribution of lung blood flow to regions with low or high VA/Q. Five patients had perfusion of units with VA/Q less than or equal to 0.07 which may cause unstable alveoli with the presently used inspiratory gas mixture. However, only two patients displayed increasing shunting suggestive of alveolar collapse during the 3.5 h observation period. This lower than expected incidence may indicate protective mechanisms against atelectasis, such as mechanical interdependence between lung units, or collateral ventilation.
Adult↗
Ventilation-perfusion relationships during epidural analgesia.
Resting lung volume (FRC), airway closure (CC) and ventilation-perfusion relationships, using the multiple inert gas elimination technique, were studied during epidural analgesia. The material consisted of 10 patients, 55-84 years of age. Epidural blockade (9-13 ml mepivacaine-adr, 1/200,000) was instituted to an upper level corresponding to Th3-Th6. Minute ventilation and breathing frequency remained unchanged during the epidural block, while cardiac output was significantly increased (4.80-5.74 l/min). The relationship between FRC and CC (FRC-CC) was unchanged during the block, indicating an unchanged magnitude of airway closure. Multiple inert gas elimination data revealed virtually unchanged distribution of ventilation and perfusion during the epidural block in 9 of the 10 patients. It is concluded that lumbar epidural analgesia up to Th3-Th6 does not influence the degree of airway closure, nor does it cause VA/Q mismatching as general anaesthesia does.
Aged↗
Actions on gamma-motoneurones elicited by electrical stimulation of group I muscle afferent fibres in the hind limb of the cat.
The reflex actions, elicited by graded electrical stimulation of hind-limb muscle, skin and joint nerves were studied in an extended series of experiments in extra-and intracellular recordings from 120 lumbar gamma-motoneurones of cats anaesthetized with chloralose. The present report deals with the action of group I muscle afferent fibres, which was examined in ninety-five gamma-cells. Of the gamma-cells 83% were classified as either static or dynamic by stimulation in the mesencephalic area for dynamic control. The general responsiveness (i.e. number of input nerves with effect/number of input nerves tested) of the cells was very high (89.9%). The responsiveness to stimulation of group I muscle afferent fibres was extremely low, both in flexor and extensor gamma-motoneurones and irrespective of whether they were static or dynamic. There was no difference, as regards the low incidence of group I muscle reflex action, between stimulation of autogenetic and heteronymous nerves. Among the rare reflex effects elicited from group I muscle fibres inhibition was four times as frequent as excitation. Inhibitory effects could be provoked from the autogenetic as well as from the heteronymous nerves. In contrast, excitatory effects were almost always autogenetic. The scarcity of group I muscle action on gamma-motoneurones is in striking contrast to the well known and powerful reflex actions of Ia and Ib fibres on alpha-motoneurones. These findings are discussed in relation to the concept of alpha-gamma linkage, and it is concluded that skeletomotor and fusimotor activity cannot be rigidly linked under all conditions.
Action Potentials↗
Actions on gamma-motoneurones elicited by electrical stimulation of group II muscle afferent fibres in the hind limb of the cat.
The reflex effects elicited by electrical stimulation of group II muscle afferent fibres were recorded with micro-electrodes in ninety-eight hind-limb gamma-motoneurones of cats anaesthetized with chloralose. Eighty-one of the gamma-cells were classified as either static or dynamic by means of stimulation in the mesencephalic area for dynamic control known to influence dynamic gamma-motoneurones selectively. A high responsiveness to activity in group II muscle fibres was found for the whole sample of gamma-cells. Group II muscle action on dynamic gamma-motoneurones was found to be more frequent than that on static ones. Excitation from group II fibres outweighed inhibition. This was clear cut for flexor gamma-motoneurones. In extensor gamma-cells, excitation prevailed by a small margin only. However, for both static and dynamic extensor gamma-cells, excitation prevailed from both posterior biceps--semitendinosus and the gastrocnemius--soleus nerves, whereas inhibition was more frequent from the deep peroneal and quadriceps nerves. All the reflex effects studied were likely to be mediated via oligosynaptic pathways. The shortest latencies of excitatory effects were compatible with a disynaptic coupling. The fastest inhibitions were presumably trisynaptic. The present findings, supported by a parallel study of reflexes evoked by group III muscle afferents, strongly suggest that the reflexes on gamma-motoneurones are not organized in accordance with the concept of flexion reflex afferents as conceived for alpha-motoneurones. The interpretation of the results suggests a particularly independent position for dynamic gamma-cells in relation to alpha- and static gamma-motoneurones. Hence, the results also furnish an argument against the concept of alpha-gamma linkage.
Action Potentials↗
Actions on gamma-motoneurones elicited by electrical stimulation of group III muscle afferent fibres in the hind limb of the cat.
The reflex actions evoked by electrical stimulation of group III muscle afferent fibres were investigated with micro-electrode recordings from ninety-three gamma-motoneurones projecting to hind-limb muscles of cats anaesthetized with chloralose. For seventy-eight of the ninety-three gamma-cells the frequency of occurrence and types of effects mediated via group II and group III muscle fibres were compared. Seventy-seven of the cells tested at intensities which excited group III and seventy-five of the cells tested at intensities which excited both group II and group III afferent fibres were classified as either static or dynamic, using the method of mesencephalic stimulation (Appelberg, 1981). The responsiveness of the whole sample of gamma-motoneurones to inputs from group III muscle fibres was high and comparable to that found with group II fibres. It was found that group III muscle fibres acted preferentially on static gamma-motoneurones. In contrast, group II fibres acted preferentially on dynamic gamma-motoneurones. Both excitatory and inhibitory effects were provoked by stimulation of group III fibres. Generally excitation was more frequent than inhibition. A strong dominance of excitation over inhibition was found in flexor muscles, and a weaker prevalence of excitation was also encountered in extensor muscles. This prevalence of excitation in extensor gamma-motoneurones is in contrast to the striking predominance of group III-evoked inhibition of extensor alpha-motoneurones as described by the flexion reflex afferents concept. A comparative survey is also given of the patterns of responses elicited in individual posterior biceps-semitendinosus and gastrocnemius-soleus gamma-cells by stimulation of group II and group III fibres. These data further corroborate the view that reflexes from high-threshold muscle afferent fibres to gamma-motoneurones are organized differently from those to alpha-motoneurones. The functional implications of these findings are discussed. It is proposed that the pools of gamma-motoneurones should be considered as integrative systems intercalated between descending and reflex pathways on the one hand and the skeletomotor neurones on the other. The descending messages and the multisensory peripheral information, integrated in the fusimotor neurones, undergo final adjustment in the muscle spindle. The link to the skeletomotor neurones is formed by the primary spindle afferents. These constitute a final common input, conveying integrated detailed polymodal feed-back, to the central nervous system. This new concept is referred to as the 'final common input' hypothesis.
Action Potentials↗
Recurrent actions on gamma-motoneurones mediated via large and small ventral root fibres in the cat.
Effects on single lumbar gamma-motoneurones, mediated via fibres running in the ventral roots, were studied by micro-electrode recording in cats anaesthetized with chloralose. Graded electrical stimulation of ventral roots or of peripheral nerves was used. The cells were identified as gamma-motoneurones by antidromic stimulation and by measurement of their axonal conduction velocity. Some of the cells were classified as static or dynamic. The findings confirm the previously demonstrated existence of low-threshold, presumed recurrent, inhibition of both static and dynamic gamma-motoneurones. Strong evidence for the occurrence of high-threshold recurrent inhibition of gamma-motoneurones is also presented. In addition, excitatory effects on gamma-cells, also mediated via fibres in the ventral roots, are described. The low-threshold effects from ventral root fibres are attributed to recurrent alpha-collateral activity and the high-threshold effects to gamma-collateral activity. The significance of recurrent inhibition of gamma-motoneurones is discussed in relation to the 'gain regulator' concept proposed by Hultborn, Lindström & Wigström (1979).
Action Potentials↗
Intrathyroidal concentrations of methimazole in patients with Graves' disease.
A sensitive gas chromatographic-mass spectrometric method enabled us to study intrathyroidal concentrations of methimazole in 20 euthyroid patients with Graves' disease on treatment with carbimazole and T4. There was no difference between patients receiving a final dose of carbimazole (10 mg), known to be totally bioactivated to methimazole (6.1 mg), 3-6 h before thyroid excision (518 ng/g thyroid tissue +/- 90 SEM) and patients who received the same dose 17-20 h before excision (727 ng/g thyroid tissue +/- 157 SEM), indicating a slow intrathyroidal turnover of the drug. On the other hand, the serum concentrations were much higher in the first group (102 ng/ml +/- 5 SEM vs. 16 ng/ml +/- 3 SEM), reflecting a short plasma half-life of the drug. The intrathyroidal concentrations of methimazole ranged from 230-1895 ng/g among individual glands but were similar in pieces from different parts of a single gland. These methimazole concentrations are lower than the concentrations reported by others to have an immunosuppressive action on lymphocytes in vitro.
Adult↗