Biomedical subjects

H Johansson

Publications and source records attributed to H Johansson.

At least 37 records · Page 2Linked to original sources

PubMed2002

Sympathetic modulation of muscle spindle afferent sensitivity to stretch in rabbit jaw closing muscles.

Previous reports showed that sympathetic stimulation affects the activity of muscle spindle afferents (MSAs). The aim of the present work is to study the characteristics of sympathetic modulation of MSA response to stretch: (i) on the dynamic and static components of the stretch response, and (ii) on group Ia and II MSAs to evaluate potentially different effects. In anaesthetised rabbits, the peripheral stump of the cervical sympathetic nerve (CSN) was stimulated at 10 impulses s(-1) for 45-90 s. The responses of single MSAs to trapezoidal displacement of the mandible were recorded from the mesencephalic trigeminal nucleus. The following characteristic parameters were determined from averaged trapezoidal responses: initial frequency (IF), peak frequency at the end of the ramp (PF), and static index (SI). From these, other parameters were derived: dynamic index (DI = PF - SI), dynamic difference (DD = PF - IF) and static difference (SD = SI - IF). The effects of CSN stimulation were also evaluated during changes in the state of intrafusal muscle fibre contraction induced by succinylcholine and curare. In a population of 124 MSAs, 106 units (85.4 %) were affected by sympathetic stimulation. In general, while changes in resting discharge varied among different units (Ia vs. II) and experimental conditions (curarised vs. non-curarised), ranging from enhancement to strong depression of firing, the amplitude of the response to muscle stretches consistently decreased. This was confirmed and detailed in a quantitative analysis performed on 49 muscle spindle afferents. In both the non-curarised (23 units) and curarised (26 units) condition, stimulation of the CSN reduced the response amplitude in terms of DD and SD, but hardly affected DI. The effects were equally present in both Ia and II units; they were shown to be independent from gamma drive and intrafusal muscle tone and not secondary to muscle hypoxia. Sympathetic action on the resting discharge (IF) was less consistent. In the non-curarised condition, IF decreased in most Ia units, while in II units decreases and increases occurred equally often. In the curarised condition, IF in group II units mostly increased. The results have important functional implications on the control of motor function in a state of 'high' sympathetic activity, like excessive stress, as well as in certain pathological conditions such as sympathetically maintained pain.

Animals↗

PubMed2002

Spreading of fatigue-related effects from active to inactive parts in the medial gastrocnemius muscle of the cat.

In the medial gastrocnemius muscle of the decerebrate cat, the spatial spread of fatigue between active and inactive muscle parts was studied. Conditioning fatiguing stimulation (CFS) was applied to a part of the muscle to test whether it had an effect on the contraction efficiency in an unstimulated part. To exclude somato-sympathetic reflexes during CFS, a full rhizotomy of the lumbo-sacral spinal cord was performed. The same ipsilateral ventral root, either L7 or S1, was divided into seven filaments, one of which was used for the test stimulation, and four or five for CFS. The CFS consisted of 12 s sessions of distributed stimulation of five (or four) filaments at a rate of 40 s(-1), the sessions were repeated, every 40 s, 15 or more times. The test consisted of 12 s of regular stimulation at a rate of 10 s(-1), preceded and followed by a single stimulus. The tests applied just after CFS showed a strong decline of both tension and electromyogram (EMG), amounting to only [mean (SD)] 0.45 (0.18) and 0.51 (0.19) (n = 15), respectively, of the corresponding values in the tests before CFS. It thus turned out that depressive fatigue-related effects could spread within the muscle. At the same time, control reactions recorded in the lateral gastrocnemius during stimulation of its cut nerve did not change. Subsequent repetitions of the tests usually revealed a tendency towards restoration. The EMG reactions recovered more quickly than tension. The depression of EMG after CFS was accompanied by a slowing of the constituent M-waves; their latencies decreased during restoration. Distinct changes in the systemic blood pressure were observed during CFS. These changes were usually correlated well with muscle tension changes. The factors possibly underlying the observed effects may include diffusion of metabolites from active to inactive muscle fibres, lowering of the efficiency of neuro-muscular transmission due to squeezing of efferent motor terminals and changes in outer metabolite content, as well as local hypoxia due to increases in intramuscular pressure.

Animals↗

PubMed2002

Information-theoretic analysis of de-efferented single muscle spindles.

The information transmission properties of single, de-efferented primary muscle-spindle afferents from the hind limb of the cat were investigated. The gastrocnemius medialis muscle was stretched randomly while recording spike trains from several muscle-spindle afferents in the dorsal root. Two classes of input stimuli were used: (i) Gaussian noise with band-limited flat spectrum, and (ii) Gaussian noise with a more "naturalistic" 1/f(n) spectrum. The "reconstruction" method was used to calculate a lower bound to the information rate (in bits per second) between the muscle spindles and the spinal cord. Results show that in response to the flat-spectrum input, primary muscle-spindle afferents transfer information mainly about high frequencies, carrying 2.12 bits/spike. In response to naturalistic-spectrum inputs, primary muscle-spindle afferents transfer information about both low and high frequencies, with "spiking efficiency" increasing to 2.67 bits/spike. A simple muscle-spindle simulation model was analyzed with the same method, emphasizing the important part played by the intrafusal fiber mechanical properties in information transmission.

Action Potentials↗

PubMed2002

The surgeon as a prognostic factor after the introduction of total mesorectal excision in the treatment of rectal cancer.

BACKGROUND: With conventional blunt surgical resection of rectal cancer, local recurrence rates are high and the individual surgeon putatively influences patient outcome. With total mesorectal excision (TME) local recurrence rates have been reduced and intersurgeon variability may be less important. The 'TME project' was a collaborative project that included surgical workshops in Stockholm between 1994 and 1997. The aim of this study was to assess the impact of the project on the practice of rectal cancer surgery in Stockholm and to analyse whether surgeon case volume and participation in the workshops influenced patient outcome. METHODS: All 652 patients who had an abdominal resection for rectal cancer in Stockholm between 1995 and 1997 were included. Outcome was compared in patients operated on by teams that included high-volume surgeons (more than 12 operations per year) with teams that included low-volume surgeons (12 operations or fewer per year), as well as between teams that including workshop participants and non-participants. RESULTS: Forty-six surgeons operated on the 652 patients. Five high-volume surgeons operated on 48 per cent of the patients. In these, outcome was significantly better than in patients treated by low-volume surgeons (local recurrence rate 4 versus 10 per cent (P = 0.02); rate of rectal cancer death 11 versus 18 per cent (P = 0.007)). Twenty-six surgeons were workshop participants and performed 93 per cent of the operations. Radiotherapy, TME and sphincter-preserving surgery were more common among patients treated by workshop participants. CONCLUSION: The TME project has had an impact on rectal cancer surgical practice in Stockholm. Variability in patient outcome was mainly related to case volume, with better results obtained in patients treated by high-volume surgeons.

Adult↗

PubMed2001

c-fos Expression and NADPH-d reactivity in spinal neurons after fatiguing stimulation of hindlimb muscles in the rat.

The distribution of Fos-immunoreactive (Fos-ir) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d)-reactive neurons in the rat lumbar spinal cord was examined following muscle fatigue caused by intermittent high-rate (100 s(-1)) electrical stimulation of the triceps surae muscle or the ventral root L5 (VRL5) for 30 min. Following both types of stimulation, the fatigue-related c-fos gene expression was more extensive in the L2-L5 segments on the stimulated side, and the majority of Fos-ir neurons were concentrated in the dorsal horn. After direct muscle stimulation, the highest number of Fos-ir neurons were detected in two regions: layer 5, and superficial layers (1 and 2(o)), although many labeled cells were also found in layers 3, 4, 6, and 7. In response to VRL5 stimulation, the maximal density of Fos-ir neurons was detected in the middle and lateral parts of layers 1 and 2(o), the zone of termination of high-threshold muscle afferents(.) Statistically significant prevalence of Fos-ir cell number was also found in layers 5 and 7 on the stimulated side. A few Fos-ir neurons were detected in the ventral horn (layer 8 and area 10) on both sides. The lamellar distribution of NADPH-d-reactive neurons was similar over all experimental groups of animals. In the L3-L6 segments, such reactive cells were arranged in two distinct regions: dorsal horn (layers 2(i), 3, and 5) and area 10; in the L1 and L2 segments, an additional cluster of NADPH-d positive cells was found in the intermediolateral cell column (IML). Double-labeled cells were not detected. We suggest that c-fos expression in response to muscle fatigue reveals activity of functionally different types of spinal neurons which could operate together with NOS-containing cells in pre-motoneuronal networks to modulate the motoneuron output.

Animals↗

PubMed2001

Effect of raloxifene on IGF-I and IGFBP-3 in postmenopausal women with breast cancer.

The effect on the IGF system of 60 mg and 600 mg daily of raloxifene administered for 2 weeks prior to surgery was investigated in 37 postmenopausal women with breast cancer. Raloxifene significantly decreased insulin-like growth factor (IGF-I) as compared to placebo (P < 0.05) with no dose-response relationship. No significant change was observed in IGFBP-3, while the IGF-I/IGFBP-3 molar ratio was decreased by treatment, with a statistically significant effect only for the higher dose. Given that high plasma levels of IGF-I have been suggested as a risk factor for breast cancer, these findings provide further support for the potential activity of raloxifene in breast cancer prevention.

Aged↗

PubMed2001

The Stockholm II trial on preoperative radiotherapy in rectal carcinoma: long-term follow-up of a population-based study.

BACKGROUND: The Stockholm II trial is a population-based prospective randomized trial on preoperative radiotherapy in rectal carcinoma. METHODS: Eligibility criteria were age younger than 80 years and biopsy-proven adenocarcinoma of the rectum judged resectable for cure with an abdominal procedure. Between 1987 and 1993, 557 patients were included. Patients were randomized to preoperative radiotherapy (RT+) followed by surgery within a week (n = 272) or surgery alone (RT-; n = 285). Radiotherapy was given with 25 grays in 1 week to the rectum and pararectal tissues. Curative resection was performed in 481 patients (86%). Median follow-up was 8.8 years. RESULTS: Among patients who underwent curative surgery, the incidence of pelvic recurrence was 12% (RT+) and 25% (RT-), respectively (P < 0.001). The overall survival rate in irradiated patients who underwent curative surgery was improved (46%) versus (39%; P < 0.03). For all included patients, the difference was 39% (RT+) compared with 36% (RT-; P = 0.2). Within 6 months of surgery, 13 of 272 (5%) of the irradiated patients died of intercurrent disease versus 4 of 285 (1%) of the nonirradiated (P = 0.02). Cardiovascular death was the main cause of intercurrent death and occurred in 35 of 272 (13%) of the irradiated patients compared with 20 of 285 (7%) among the nonirradiated (P = 0.07). CONCLUSIONS: Preoperative short-term radiotherapy reduces the risk of pelvic recurrence and can improve survival after curative surgery for rectal carcinoma. An increased risk of intercurrent death may reduce the benefit especially in elderly patients.

Adenocarcinoma↗

PubMed2001

[Rapid recovery after colonic resection. Multimodal rehabilitation by means of Kehlet's method practiced in Vasteras].

UNLABELLED: By using a multimodal rehabilitation program professor Kehlet has shown accelerated recovery after colonic surgery with hospital stay of only two days, irrespective of open or laparoscopic technique. These results have not been confirmed in other studies. The aim of this study was to replace our traditional approach with Kehlet's multimodal regimen and try to reproduce his reported data. METHODS: 22 patients (median age 67 years) underwent right- or leftsided colectomies, 15 open (7 with midline incisions) and 7 laparoscopically. Continuous thoracic epidural, immediate mobilization and oral nutrition were used. Discharge was planned three days after surgery. On the first postoperative day all had oral intake and on the third day patients were mobilized for a median of 9.7 hours and all had resumed defecation. Pain and fatigue scores (VAS) were low. The median post-operative hospital stay was 3.5 (range 3-8) days. Two patients returned with complications. No cardiopulmonary or infectious complications were seen. The multimodal rehabilitation programme resulted in a quick recovery and a hospital stay of three days in most patients after colonic surgery.

Adult↗

PubMed2001

Sucrose and light regulation of a cold-inducible UDP-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in Arabidopsis.

UDP-glucose pyrophosphorylase (UGPase) is a key enzyme producing UDP-glucose, which is involved in an array of metabolic pathways concerned with, among other functions, the synthesis of sucrose and cellulose. An Arabidopsis thaliana UGPase-encoding gene, Ugp, was profoundly up-regulated by feeding sucrose to the excised leaves and by an exposure of plants to low temperature (5 degrees C). The UGPase activity and its protein content also increased under conditions of sucrose feeding and exposure to cold. The sucrose effect on Ugp was apparently specific and was mimicked by exposure of dark-adapted leaves to light. Drought and O2 deficiency had some down-regulating effects on expression of Ugp. The sugar-signalling pathway for Ugp regulation was independent of hexokinase, as was found by using transgenic plants with increased and decreased expression of the corresponding gene. Subjecting mutants deficient in abscisic acid (ABA) to cold stress conditions had no effect on Ugp expression profiles. Okadaic acid was a powerful inhibitor of Ugp expression, whereas it up-regulated the gene encoding sucrose synthase (Sus1), indicating distinct transduction pathways in transmitting the sugar signal for the two genes in A. thaliana. We suggest that Ugp gene expression is mediated via a hexokinase-independent and ABA-insensitive pathway that involves an okadaic acid-responsive protein phosphatase. The data point towards Ugp as a possible regulatory entity that is closely involved in the homoeostatic readjustment of plant responses to environmental signals.

Abscisic Acid↗

PubMed2001

Retention of conservative and sorptive solutes in streams--simultaneous tracer experiments.

The effective transport velocity of solutes in rivers and streams is governed by transient storage in hyporheic zones in which the longitudinal advection velocity is small relative to the main stream flow velocity. Results from a simultaneous tracer experiment using a non-reactive (tritium, 3H2O) and a sorptive tracer [chromium, 51Cr(III)] have formed the basis of a more accurate interpretation of the retention characteristics of solutes in streams than previously has been possible. By using a simultaneous injection of these two tracers, it was possible to distinguish between their different behaviours. Based on estimations of fluxes, the retained mass of chromium in the storage zones along the 30-km-long study-reach was 76% after 150 h. Independent observations in the bed sediment indicated that the loss of chromium observed in the water was mainly a result of uptake into the bed sediment. To describe the transport in the stream, a model concept including solute sorption kinetics in the bed sediment was proposed. Evaluation of parameters in the model, indicated that the uptake of chromium in the bed sediment is controlled by sorption kinetics.

Journal Article↗

PubMed2001

Glutamate NMDAR1 receptors localised to nerves in human Achilles tendons. Implications for treatment?

In this investigation, we show the presence of both free glutamate (microdialysis) and glutamate NMDAR1 receptors (immunohistochemical analyses of tendon biopsies), in tendons from patients with chronic Achilles tendon pain (Achilles tendinosis) and in controls (pain-free tendons). The NMDAR1 immunoreaction was usually confined to acetylcholinesterase-positive structures, implying that the reaction is present in nerves. Glutamate is a potent pain mediator in the human central nervous system, and in animals it has been shown that peripherally administered glutamate NMDA receptor antagonists diminish the response to formalin-induced nociception. Our present finding of glutamate NMDA receptors in human Achilles tendons might have implications for pain treatment.

Achilles Tendon↗

PubMed2001

Phosphate status affects the gene expression, protein content and enzymatic activity of UDP-glucose pyrophosphorylase in wild-type and pho mutants of Arabidopsis.

The effects of inorganic phosphate (Pi) deficiency on the expression of the UDP-glucose pyrophosphorylase (UGPase) gene (Ugp), involved in sucrose synthesis/metabolism, and on carbohydrate status were investigated in different tissues of Arabidopsis thaliana (L.) Heynh. For leaves, a decrease in internal Pi status caused by growth of plants on a medium lacking Pi (-P conditions) led to an increase in the overall content of glucose and starch, but had little effect on sucrose content. The Pi deficiency also led to an increased carbohydrate content in stems/flowers, but not in roots. The expression of Ugp was upregulated in both leaves and roots, but not in stems/flowers. The effects of Pi status on Ugp expression were confirmed using leaves of both pho1-2 and pho2-1 mutants of Arabidopsis (Pi-deficient and Pi-accumulating, respectively) and by feeding the leaves with D-mannose, which acts as a sink for Pi. The Pi-status-dependent changes in Ugp expression followed the same patterns as those of ApS, a gene encoding the small subunit of ADP-glucose pyrophosphorylase, a key enzyme of starch synthesis. The changes in Ugp mRNA levels, depending on internal Pi status, were generally correlated with changes in UGPase protein content and enzymatic activity. This was demonstrated both for wild-type plants grown under Pi-deficiency and for Pi mutants. The data suggest that, under Pi-deficiency, UGPase represents a transcriptionally regulated step in sucrose synthesis/metabolism, involved in homeostatic mechanisms readjusting the nutritional status of a plant under Pi-stress conditions.

Arabidopsis↗

PubMed2001

Influences on the fusimotor-muscle spindle system from chemosensitive nerve endings in cervical facet joints in the cat: possible implications for whiplash induced disorders.

The aim of the present study was to establish if there exists reflex connections from ligamentous structures in cervical facet joints and the fusimotor system of dorsal neck muscles. In seven cats, anaesthetized with alpha-chloralose, bradykinin (BK) of concentrations between 12 and 50 microg was injected into the facet joint between C1 and C2. Recordings were made from single muscle spindle afferents (MSA) originating in contralateral trapezius and splenius muscles (TrSp). Fusimotor induced changes in the sensitivity of the muscle spindle afferents were assessed by recording the responses to sinusoidal stretches of the TrSp muscles. The mean rate of discharge and the depth of modulation of a fitted sine were taken as quantitative estimates of the response. A total of 25 MSAs were recorded, and 21 of these showed clear-cut alterations in their responses to the sinusoidal stretches following Bk. injections into contralateral facet joint. The majority of the responding afferents (13/21) showed changes in their responses indicating an increased activity of static fusimotoneurones, although responses of dynamic and mixed static and dynamic nature were also seen. Local anaesthetics applied to the intraarticular receptors abolished the effects. Injection (i.v.) of a general anaesthetic (pentobarbital) abolished the effects. The results show that there exist reflex connections between receptors in cervical facet joints and fusimotoneurones of dorsal neck muscles, and this might be of importance in the pathophysiology behind whiplash associated disorders (WAD).

Animals↗

PubMed2001

Effect of low dose tamoxifen on the insulin-like growth factor system in healthy women.

The use of tamoxifen as a preventive agent may be limited by the increased risk of endometrial cancer and venous thromboembolic events observed in postmenopausal women. We have recently shown a comparable activity of lower doses of tamoxifen on several surrogate biomarkers of cardiovascular disease and breast cancer, including Insulin-like Growth Factor-I (IGF-I). To provide further insight into the effect of tamoxifen at low doses on the IGF system, we have correlated the drug serum levels attained after 2 months of either placebo (n = 32), tamoxifen 20 mg/day (n = 26), 10 mg/day (n = 23) or 10 mg/every other day (n = 29) with the changes in IGF-I, Insulin-like Growth Factor-II (IGF-II), Insulin-like Growth Factor Binding Protein-1 (IGFBP-1), Insulin-like Growth Factor Binding Protein-3 (IGFBP-3), and IGF-I/IGFBP-3 ratio. Compared with placebo, tamoxifen induced a mean +/- standard error (SE) reduction of IGF-I of 16.9 +/- 7.8%, p < 0.05, a non-significant increase of 22.9 +/- 12.2% in IGF-II, an increase in IGFBP-1 of 49.3 +/- 22.7%, p < 0.05, and a non-significant change of IGFBP-3 (-4.0% +/- 9.2). No significant concentration-response relationship was observed between serum tamoxifen concentrations and the biomarker changes except for the ratio of IGF-I/IGFBP-3, which decreased by 1.53 +/- 0.68% for any increase by 10 ng/ml of serum tamoxifen concentration (p = 0.02). Although low tamoxifen concentrations induce a comparable modulation of the IGF family relative to the conventional dose, the lower decrements in the IGF-I/IGFBP-3 ratio observed at low drug concentrations might be associated with a reduced preventive activity. Further studies on the search of the minimal active dose of tamoxifen are warranted.

Anticarcinogenic Agents↗

PubMed2001

Tumour location and the effects of preoperative radiotherapy in the treatment of rectal cancer.

BACKGROUND: Preoperative radiotherapy improves local control and survival in rectal cancer, but may also increase postoperative morbidity and mortality rates. Establishing selection criteria for preoperative radiotherapy is crucial. The tumour level above the anus may be one such criterion. The effect of preoperative radiotherapy in relation to the distance between the tumour and the anus was therefore assessed. METHODS: In 457 patients operated for cure included in the Stockholm II Trial the local recurrence rate in irradiated and non-irradiated patients was analysed in relation to the tumour location (low, mid or upper rectum). RESULTS: Radiotherapy reduced the local recurrence rate from 30 to 20 per cent in low rectal cancer, from 25 to 11 per cent in mid rectal cancer and from 21 to 5 per cent for tumours in the upper rectum. CONCLUSION: With conventional surgical techniques preoperative radiotherapy plays an important role in rectal cancer irrespective of the location of the tumour. To irradiate only patients with tumours in the lower rectum and to omit this treatment for patients with tumours in the mid and upper rectum cannot be recommended. Whether this statement is valid with standardized total mesorectal excision (TME) surgery is not known. Until this knowledge is available the current indications for preoperative radiotherapy should probably also be used with TME surgery.

Adenocarcinoma↗

PubMed2001

Reduction of postoperative morbidity and mortality in patients with rectal cancer following the introduction of a colorectal unit.

BACKGROUND: Surgery for rectal cancer is associated with high morbidity and mortality rates. The reason for this has been much debated. This population-based study reports the findings on postoperative morbidity and mortality after rectal cancer surgery following the introduction of a centralized colorectal unit in a county central hospital, supervised by a colorectal surgeon using the most recent techniques. METHODS: All consecutive patients with rectal cancer who underwent surgery at four county hospitals in the Västmanland county in Sweden during 1993-1996 (n = 133) were compared with patients who underwent surgery at the new colorectal unit in the county central hospital from 1996 to 1999 (n = 144). RESULTS: The number of operating surgeons was reduced from 26 to four. The postoperative mortality rate decreased from 8 to 1 per cent (P = 0.002) and the total postoperative complication rate was reduced from 57 to 24 per cent (P < 0.001). Surgical complications dropped from 37 to 11 per cent (P < 0.001). The relaparotomy rate fell from 11 to 4 per cent (P < 0.05). Postoperative stay in hospital was reduced from a median of 13 to 9 days (P < 0.001). CONCLUSION: The new organization, with centralized rectal cancer surgery using modern techniques, reduced postoperative mortality and overall morbidity rates to less than half.

Adult↗

PubMed2001

Replication and discrimination of limb movement velocity.

It is well known that proprioception is composed of the senses of movement and position. Whereas tests of position sense are quite commonly used, tests of the acuity in perception of movement velocity are scarce. In the present study we examined some novel tests for assessing the sense of limb movement velocity, involving replication and discrimination of single-joint movement velocity. Specifically, we investigated: (1) whether replication of limb movement velocity is more accurate following active criterion movements as compared to passive; (2) whether antagonist muscle contraction during passive limb movement enhances velocity discrimination; (3) how criterion movement velocity influences response accuracy; (4) the relationship between movement velocity and movement extent during velocity replication; and (5) whether subjects really base discrimination of velocities on perceived velocity. Sixteen healthy subjects participated in four tests (I-IV). For each test, horizontal abductions were performed about the right glenohumeral joint from the sagittal plane. The subjects were required to actively replicate the velocity of either an active (Test I) or passive (Test II) criterion movement, or judge whether a passive/semipassive (passive during antagonist muscle contraction) movement was faster or slower than a previous passive/semipassive criterion movement (Test III/IV). The results revealed higher response accuracy for Test I compared to Test II and for slower movements compared to faster, but no difference in response accuracy between Test III and IV. For velocity discrimination, the analysis revealed that the subjects based their judgment on the difference between criterion and comparison velocity rather than time or extent cues.

Adult↗

PubMed2001

Chromogranin A in human neuroendocrine tumors: an immunohistochemical study with region-specific antibodies.

Antibodies to six specific regions of the chromogranin A (CgA) molecule were used to study their immunoreactivity in human neuroendocrine (NE) tumors. Tissue specimens from endocrine pancreatic tumors (n = 14), duodenal carcinoids (n = 2), bronchial carcinoids (n = 5), ileal carcinoids (n = 5) appendix carcinoids (n = 2), medullary thyroid carcinomas (n = 6), parathyroid adenomas (n = 2), and pheochromocytomas (n = 8) were analyzed. The results showed that the NE tumor types expressed varying numbers of CgA fragments. A variation in frequency of the expression of immunoreactive cells was sometimes seen also within the same tumor type. The midportion fragment CgA 176-195 (chromacin) was the only fragment expressed in all tumors. Benign and malignant tumors expressed different patterns, being especially true of insulinomas and pheochromocytomas. These findings suggest that region-specific antibodies to CgA fragments can be used as a diagnostic tool for the characterization of NE tumors.

Adenoma↗