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Biomedical subjects

Pax H B Willemse

Publications and source records attributed to Pax H B Willemse.

At least 19 recordsLinked to original sources

Distinguishing benign and malignant pelvic masses: the value of different diagnostic methods in everyday clinical practice.

OBJECTIVE: To optimize referral to specialized gynaecologists for surgical treatment of ovarian cancer by improving preoperative discrimination between benign and malignant pelvic tumours. STUDY DESIGN: In a prospective multicentre study 143 patients with a pelvic mass were included. At several occasions during the diagnostic work-up the gynaecologist estimated the chance of malignancy (educated guess/expert opinion). MRI in the local setting was suggested for uncertain cases. All MRI images were reviewed by an expert radiologist. The datasheet designed for the study further allowed for determining the risk of malignancy index (RMI). RESULTS: The diagnostic accuracy of the gynaecologist's final estimation of the chance of malignancy and the calculated RMI were comparable (area under the ROC curve of 0.87 and 0.86). MRI did not improve the accuracy of the diagnostic work-up for the study population as a whole. Subgroup analysis did however show improved diagnostic accuracy in cases with an estimated chance of malignancy between 20 and 80% when the MRI was read by an expert radiologist. CONCLUSION: Patient selection for surgery of a pelvic mass should be based on the chance of malignancy as assigned by the referring gynaecologists. In case of uncertainty MRI improves diagnostic accuracy, when judged by an expert.

Adolescent↗

Gynecologic examination and cervical biopsies after (chemo) radiation for cervical cancer to identify patients eligible for salvage surgery.

PURPOSE: The aim of this study was to evaluate efficacy of gynecologic examination under general anesthesia with cervical biopsies after (chemo) radiation for cervical cancer to identify patients with residual disease who may benefit from salvage surgery. METHODS AND MATERIALS: In a retrospective cohort study data of all cervical cancer patients with the International Federation of Gynecology and Obstetrics (FIGO) Stage IB1 to IVA treated with (chemo) radiation between 1994 and 2001 were analyzed. Patients underwent gynecologic examination under anesthesia 8 to 10 weeks after completion of treatment. Cervical biopsy samples were taken from patients judged to be operable. In case of residual cancer, salvage surgery was performed. RESULTS: Between 1994 and 2001, 169 consecutive cervical cancer patients received primary (chemo) radiation, of whom 4 were lost to follow-up. Median age was 56 years (interquartile range [IQR], 44-71) and median follow-up was 3.5 years (IQR, 1.5-5.9). In each of 111 patients a biopsy sample was taken, of which 90 (81%) showed no residual tumor. Vital tumor cells were found in 21 of 111 patients (19%). Salvage surgery was performed in 13 of 21 (62%) patients; of these patients, 5 (38%) achieved long-term, complete remission after salvage surgery (median follow-up, 5.2 years; range, 3.9-8.8 years). All patients with residual disease who did not undergo operation (8/21) died of progressive disease. Locoregional control was more often obtained in patients who underwent operation (7 of 13) than in patients who were not selected for salvage surgery (0 of 8 patients) (p < 0.05). CONCLUSIONS: Gynecologic examination under anesthesia 8 to 10 weeks after (chemo) radiation with cervical biopsies allows identification of those cervical cancer patients who have residual local disease, of whom a small but significant proportion may be salvaged by surgery.

Adenocarcinoma↗

The prognostic effect of the number of histologically examined axillary lymph nodes in breast cancer: stage migration or age association?

BACKGROUND: The number of pathologically examined axillary nodes has been associated with breast cancer survival, and examination of >or=10 nodes has been advocated for reliable axillary staging. The considerable variation observed in axillary staging prompted this population-based study, which evaluated the prognostic effect of a variable number of pathologically examined nodes. METHODS: In total, 5314 consecutive breast cancer patients who underwent mastectomy or breast-conserving surgery and axillary dissection between 1994 and 1999 were included. The prognostic effect of the examined number of nodes was assessed with crude and relative survival analysis. RESULTS: A median number of 12 (range, 1-43) nodes were histologically examined, and 59% of the patients had no nodal tumor involvement. The number of examined nodes decreased with age (P<.001) and increased with tumor size (P<.001). Stratified for the number of tumor-positive nodes, overall survival seemed to be worse for patients with <10 compared with patients with >or=10 examined nodes (P<.001), whereas the relative survival did not differ. After adjusting for age, tumor size, number of positive nodes, and detection by screening in a multivariate analysis, the number of examined nodes was not associated with relative survival. CONCLUSIONS: This study shows that the association between the number of pathologically examined axillary nodes and overall survival in node-negative and node-positive patients results from stage migration. The absence of an association between the number of examined nodes and relative survival further indicates that the association between the number of examined nodes and crude survival is confounded by age.

Age Factors↗

Quality of life versus prolongation of life in patients treated with chemotherapy in advanced colorectal cancer: A review of randomized controlled clinical trials.

Oncologists disagree if chemotherapy in advanced cancer can improve quality of life (QoL), to prolong duration of life, or both. The objective of this study was to clarify the main treatment intention of palliative chemotherapy (PCT): the prolongation of life (PoL); or QoL. Randomized controlled clinical trials of PCT in advanced colorectal cancer that included HRQoL assessment were selected from PubMed and reviewed. Authors' conclusions were based on both PoL- and QoL-related outcomes. However, if PoL and QoL outcomes of the experimental arm were opposite, which was the case in 13 out of 28 trials, the authors generally based their conclusion on PoL outcomes. Authors' conclusions focused mainly on PoL-related outcomes, while QoL-related outcomes were of overriding importance in only 1/28 case. QoL can therefore not be considered as the main outcome of PCT. The review shows that in the context of chemotherapy in advanced colorectal cancer, 'palliative' refers to a life-prolonging intention, whereas within palliative care it refers to an improvement in QoL.

Antineoplastic Combined Chemotherapy Protocols↗

Surgery by consultant gynecologic oncologists improves survival in patients with ovarian carcinoma.

BACKGROUND: Consultant gynecologic oncologists from the regional Comprehensive Cancer Center assisted community gynecologists in the surgical treatment of patients with ovarian carcinoma when they were invited. For this report, the authors evaluated the effects of primary surgery by a gynecologic oncologist on treatment outcome. METHODS: The hospital files from 680 patients with epithelial ovarian carcinoma who were diagnosed between 1994 and 1997 in the northern part of the Netherlands were abstracted. Treatment results were analyzed according to the operating physician's education by using survival curves and univariate and multivariate Cox regression analyses. RESULTS: Primary surgery was performed on 184 patients by gynecologic oncologists, and on 328 patients by general gynecologists. Gynecologic oncologists followed surgical guidelines more strictly compared with general gynecologists (patients with International Federation of Gynecology and Obstetrics [FIGO] Stage I-II disease, 55% vs. 33% [P=0.01]; patients with FIGO Stage III disease, 60% vs. 40% [P=0.003]) and more often removed all macroscopic tumor in patients with FIGO Stage III disease (24% vs. 12%; P=0.02). When patients were stratified according to FIGO stage, the 5-year overall survival rate was 86% versus 70% (P=0.03) for patients with Stage I-II disease and 21% versus 13% (P=0.02) for patients with Stage III-IV disease who underwent surgery by gynecologic oncologists and general gynecologists, respectively. The hazards ratio for patients who underwent surgery by gynecologic oncologists was 0.79 (95% confidence interval [95%CI], 0.61-1.03; adjusted for patient age, disease stage, type of hospital, and chemotherapy); when patients age 75 years and older were excluded, the hazards ratio fell to 0.71 (95% CI, 0.54-0.94) in multivariate analysis. CONCLUSIONS: The surgical treatment of patients with ovarian carcinoma by gynecologic oncologists occurred more often according to surgical guidelines, tumor removal more often was complete, and survival was improved.

Adult↗

Hot flushes in breast cancer patients.

OBJECTIVES: A literature search was conducted to gather information concerning the pathophysiologic mechanisms leading to hot flushes, their prevalence and severity in breast cancer patients, their influence on quality of life, and the best therapeutic option. METHODS: Relevant studies in English were selected from Medline. RESULTS AND CONCLUSION: Pathophysiologic mechanisms leading to hot flushes are poorly understood. Estrogen withdrawal is considered to have a central role. Also, serotonin and norepinephrine seem to be involved in hot flush induction. Menopause induced by chemotherapy or ovarian ablation, is accompanied by an abrupt decrease in estrogen level, causing vasomotor symptoms. Hot flushes are also a side effect of tamoxifen and aromatase inhibitors. Quality of life in breast cancer patients may be negatively influenced by hot flushes, and therefore, adequate treatment is important. Currently, of the several non-hormonal options, the selective serotonin-reuptake inhibitor (SSRI) venlafaxine is the most effective in breast cancer patients. However, studies on interaction between SSRIs and tamoxifen may influence future recommendations.

Anti-Anxiety Agents↗

Abdominal angina in patients with a midgut carcinoid, a sign of severe pathology.

In 36 consecutive patients with a foregut carcinoid with extensive local tumor growth and liver metastases with a carcinoid syndrome, six patients had complaints of postprandial abdominal pain and attacks of subileus based on segmental intestinal ischemia. A diagnosis of abdominal angina was supported by a positive response to nitroglycerin in two and ischemia of the ileum demonstrated by angiography in two other patients. Complaints were reduced in all patients after surgery. Histopathology of the resected small bowel specimens showed elastic vascular sclerosis in three patients and ischemic changes in three other patients, confirming the clinical diagnosis. Resection of ischemic bowel can provide relief in patients with segmental intestinal ischemia caused by carcinoid-induced vascular sclerosis.

Abdominal Pain↗

Clinical potential of inhibitors of survival pathways and activators of apoptotic pathways in treatment of cervical cancer: changing the apoptotic balance.

Cervical cancer is the most common gynaecological malignant disorder worldwide. The best possible treatment of locally advanced cervical cancer is a combination of radiation and cisplatin-based chemotherapy. However, 5-year overall survival is still only 52%. To improve treatment results, research should focus on the discovery of innovative drug strategies. Drugs directed at inducing tumour-cell apoptosis are regarded as important treatment modalities. Here, we present an overview of the molecular options that can change the apoptotic balance in cervical cancer, through increasing death-receptor-mediated apoptosis, the use of proteasome inhibitors, short interfering RNAs, or non-steroidal anti-inflammatory drugs (NSAIDs). Furthermore, the potential of attacking prosurvival signalling through the epidermal-growth-factor receptor and insulin-like-growth-factor receptor to support the apoptotic process is discussed. Additional research is needed to elucidate the clinical potential of these compounds in the treatment of cervical cancer.

Antineoplastic Agents↗

Quality of adjuvant CMF chemotherapy for node-positive primary breast cancer: a population-based study.

PURPOSE: Adjuvant 'classical' oral cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) has long been the mainstay of adjuvant chemotherapy for premenopausal breast cancer patients. The Comprehensive Cancer Center North Netherlands (CCCN) breast cancer working group performed a retrospective audit of treatment guideline adherence and quality of CMF in hospitals in the CCCN area. METHODS: The CMF treatment data of 251 consecutive axillary lymph node-positive breast cancer patients <50 years old, diagnosed between 1993 and 1996, were analyzed. RESULTS: Ninety-four patients (42%) completed adjuvant CMF without dose adjustment or delay. Overall median relative dose intensity (RDI) was 92.6 (IQR 85.5-97.7). Sixty patients (24%) had an RDI <85, and 7% had an RDI <65. Myelotoxicity was the main reason for reductions and delays. Of 176 irradiated patients, 96% received radiotherapy simultaneously with CMF. Median CMF dose intensity nor median duration differed between patients who underwent mastectomy, mastectomy and radiotherapy, or breast-conserving therapy. Radiotherapy did not influence the median RDI (94 without versus 92 with radiotherapy). G-CSF, administered at least once to 76 patients, did not result in a higher median RDI. Median RDI was slightly higher when >3 patients/year (P=0.014) were treated by one specialist or >10 patients classified for adjuvant chemotherapy yearly in a hospital (P=0.037). CONCLUSION: The adherence to CMF treatment guidelines was generally good. Simultaneous radiotherapy did not affect the median RDI of CMF. G-CSF had no impact on the median RDI but patient volume did influence the RDI.

Adult↗

Variability in axillary lymph node dissection for breast cancer.

BACKGROUND: The axillary nodal status may influence the prognosis and the choice of adjuvant treatment of individual breast cancer patients. The variation in number of reported axillary lymph nodes and its effect on the axillary nodal stage were studied and the implications are discussed. METHODS: Between 1994 and 1997, a total of 4,806 axillary dissections for invasive breast cancers in 4,715 patients were performed in hospitals in the North-Netherlands. The factors associated with the number of reported nodes and the relation of this number with the nodal status and the number of positive nodes were studied. RESULTS: The number of reported nodes varied significantly between pathology laboratories, the median number of nodes ranged from 9 to 15, respectively. The individual hospitals explained even more variability in the number of nodes than pathology laboratories (range in median number 8-15, P < 0.0001). The number of reported nodes increased gradually during the study period. A decreasing trend was observed with older patient age. A higher number of reported nodes was associated with a markedly increased chance of finding tumor positive nodes, especially more than three nodes. The frequency of node positivity increased from 28% if less than six nodes to 54% if >/=20 nodes were examined, the percentage of tumors with >/=4 positive nodes increased from 4 to 31%. Multivariate analysis confirmed these results. CONCLUSIONS: This population-based study showed a large variation in the number of reported lymph nodes between hospitals. A more extensive surgical dissection or histopathological examination of the specimen generally resulted in a higher number of positive nodes. Although the impact of misclassification on adjuvant treatment will have varied, the impact with regard to adjuvant regional radiotherapy may have been considerable.

Axilla↗

Cost-benefit analysis of capecitabine versus 5-fluorouracil/leucovorin in the treatment of colorectal cancer in the Netherlands.

BACKGROUND: Capecitabine is an oral prodrug of 5-fluorouracil and has been studied for the treatment of colorectal cancer. In 2 Phase III trials, capecitabine was at least as effective as 5-fluorouracil plus leucovorin and had a more favorable toxicity profile. OBJECTIVE: A cost-benefit analysis was used to assess the pharmacoeconomic profile of capecitabine compared with 5-fluorouracil/leucovorin, given according to the Mayo regimen, for colorectal cancer patients treated in the Netherlands. METHODS: The medical files of patients treated for colorectal cancer at a single center from 1999 to 2002 were examined to determine the numbers of outpatient visits for 5-fluorouracil/leucovorin administration, health care use and medication to manage adverse effects, and travel distance to and from the hospital. The costs of capecitabine treatment were simulated by assuming that the same patients were treated with capecitabine instead of 5-fluorouracil/leucovorin. Toxicity data for capecitabine were derived from 2 Phase III studies that compared capecitabine and 5-fluorouracil/leucovorin. RESULTS: The files of 65 patients were reviewed. Thirty-two patients received adjuvant treatment and 33 patients were treated palliatively for metastatic disease. The mean total costs of palliative treatment were Euro 4004 with capecitabine and Euro 5614 with 5-fluorouracil/leucovorin. These results were robust in sensitivity analyses. The cost savings were primarily related to the number of outpatient visits for capecitabine versus the number of day-care treatment days for 5-fluorouracil/leucovorin, despite the higher acquisition costs of capecitabine. CONCLUSIONS: Based on this analysis, treatment of colorectal cancer with oral capecitabine is cost saving in the Netherlands compared with 5-fluorouracil plus leucovorin administered according to the Mayo regimen. Baseline savings were estimated at Euro 1610 for palliative treatment and Euro 934 for adjuvant treatment.

Administration, Oral↗

Complications of midgut carcinoid tumors and carcinoid syndrome.

The carcinoid syndrome, associated with carcinoid tumors of the midgut, consists of symptoms such as diarrhea, flushing, wheezing and cardiovascular symptoms. This review focuses on these symptoms and discusses therapeutic options. The symptoms are caused by the secretion of biogenic amines, polypeptides and other factors of which serotonin is the most prominent. However, diarrhea is also due to factors such as malabsorption. Besides antitumor therapy, more specific interventions such as serotonin receptor blockers can be useful. The carcinoid heart disease involves the tricuspid and pulmonary valve. In the pathogenesis, serotonin plays a central role. The therapeutic approach is mostly symptomatic. Other cardiovascular complications include bowel ischemia and hypertension. Pellagra and psychiatric symptoms are due to a depletion of tryptophan, which is consumed by the carcinoid tumor for serotonin synthesis. Finally, follow-up and clinical practice of patients with carcinoid tumors are discussed.

Carcinoid Heart Disease↗

Pilot study of vaginal plethysmography in women treated with radiotherapy for gynecological cancer.

OBJECTIVE: After pelvic radiotherapy for gynecological cancer, changes in the vaginal epithelium might influence sexual arousal and satisfaction, leading to dyspareunia and relational problems. The aim of the study was to determine the feasibility of vaginal plethysmography in order to measure physical late effects of this therapy on sexual function. METHODS: Patients treated with radiotherapy for cervical, endometrial, or ovarian cancer, who were in complete remission for over 1 year, underwent vaginal plethysmography to measure changes in vaginal vasocongestion, while watching erotic video fragments. Afterward two questionnaires, designed to measure feelings of sexual arousal during the video, and to identify sexual dysfunction, were completed. The results were compared with those of healthy women. RESULTS: Patients (n = 9) and volunteers (n = 8) did not differ in baseline amplitude of plethysmography and showed comparable changes in vaginal vasocongestion during the various video fragments. The decline in amplitude during the last video fragment in the patient group did not reach significance, but the group of patients is small and heterogeneous. Addressing subjective sexual arousal during the video, patients reported less feelings of lust and desire and fewer bodily sensations while watching than the controls. Patients worried more about the sexual satisfaction of their partners than controls. CONCLUSION: Vaginal plethysmography can be used to measure vaginal vasocongestion in patients treated with radiotherapy to the proximal vagina. In this pilot study the changes of vaginal vasocongestion during sexual arousal between patients and healthy volunteers were not different. This correlates with a comparable sexual satisfaction, although patients reported less feelings of lust.

Adult↗

Intraperitoneal chemotherapy for ovarian cancer: a question of feasibility?

Increasing the tumor concentration of chemotherapeutic agents by local administration seems one logical approach to increase the efficacy of treatment. This approach is actively pursued in ovarian cancer, which allows local, intraperitoneal drug administration. In this commentary we put into perspective a recent study of Rothenberg et al. reporting on IP administration of a combination of cisplatin and paclitaxel. We argue that feasibility of IP administration of chemotherapy should not preclude its application.

Antineoplastic Combined Chemotherapy Protocols↗

Catecholamine-synthesizing enzymes in carcinoid tumors and pheochromocytomas.

BACKGROUND: Serotonin is the principal endocrine product of carcinoid tumors, but simultaneously increased production of catecholamines has been described in these tumors. As it is not clear whether these tumors contain specific enzymes for catecholamine synthesis, we aimed to detect catecholamine-synthesizing enzymes [tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), and phenylethanolamine-N-methyltransferase (PNMT)] in midgut carcinoid tumors and pheochromocytoma and to correlate enzyme expression to serotonin production as well as catecholamines and metabolites excreted in urine. METHODS: Paraffin-embedded tumor specimens from 21 midgut carcinoid patients and 20 pheochromocytoma patients (10 sporadic and 10 MEN type IIa-related tumors) were stained for TH, DBH, and PNMT, using a three-step biotin-avidin-peroxidase method. RESULTS: TH was demonstrated in 9 (43%) of 21 carcinoids and in all (100%) of 20 pheochromocytomas, DBH in 8 (38%) carcinoids and in 15 (75%) pheochromocytomas, and PNMT in 7 (33%) carcinoids and in 13 (65%) pheochromocytomas. Increased urinary excretion of catecholamines and metabolites was observed in 10 (48%) carcinoid patients and in all pheochromocytoma patients. No clinically relevant association between enzyme expression and urinary excretion of catecholamines and metabolites was found. CONCLUSIONS: Catecholamine-synthesizing enzymes are present in many carcinoid tumors. This finding possibly indicates the existence of a catecholamine-synthesizing pathway in carcinoids similar to that found in pheochromocytoma.

Adrenal Gland Neoplasms↗

Bone metastases in carcinoid tumors: clinical features, imaging characteristics, and markers of bone metabolism.

UNLABELLED: The purpose of this study was to describe the clinical presentation of bone metastases in patients with carcinoid tumors and to determine the diagnostic value of imaging techniques and markers of bone metabolism. METHODS: This retrospective study was performed on the entire group of patients with carcinoid tumors treated in our hospital from January 1992 to May 1999. Only patients with metastasized tumors were included. RESULTS: Eleven of 90 patients (12%) (95% confidence interval [CI], 5%-19%) with a metastasized carcinoid tumor had symptomatic bone metastases. All bone metastases occurred in 55 patients with midgut carcinoids (20%; 95% CI, 9%-31%). Plain radiography had a sensitivity of 44% (95% CI, 12%-76%); MRI, 100% (95% CI, 61%-100%); bone scintigraphy, 90% (95% CI, 72%-100%); and octreotide scintigraphy, 60% (95% CI, 35%-93%). In 9 patients, both octreotide scintigraphy and bone scintigraphy were performed. Of 45 bone lesions, 22 (49%) were visualized by both modalities, 13 (29%) were visualized with octreotide scintigraphy but not with bone scintigraphy, and 10 (22%) were visualized with bone scintigraphy but not with octreotide scintigraphy. In 2 patients, octreotide scintigraphy and bone scintigraphy provided complementary results. Markers of bone metabolism could not discriminate carcinoid patients from those without bone metastases. The markers of bone metabolism did not reflect the osteolytic or osteoblastic appearance of metastases. CONCLUSION: Pain is the principal symptom of bone metastases in patients with carcinoid tumors. Plain radiography and markers of bone metabolism do not contribute to the diagnosis of bone metastases. MRI has a high sensitivity for bone metastases. Both bone scintigraphy and octreotide scintigraphy have acceptable sensitivity and can provide complementary results.

Adult↗

Serum squamous cell carcinoma antigen and CYFRA 21-1 in cervical cancer treatment.

PURPOSE: To analyze whether serum squamous cell carcinoma (SCC) antigen and cytokeratin-19 fragments (CYFRA) levels can assist in selecting patients with locally advanced cervical cancer who will benefit from combined treatment or additive surgery. METHODS AND MATERIALS: Of 114 patients with cervical cancer Stage IB-IV, the first 39 patients received radiotherapy, the following 75 patients received identical radiotherapy plus concomitant chemotherapy (3 cycles of carboplatin and 5-fluorouracil). SCC antigen and CYFRA 21-1 serum levels were measured before treatment, after therapy, and during follow-up. Baseline tumor markers were related to tumor stage and size and clinical outcome. RESULTS: Before treatment, SCC antigen was elevated (>1.9 microg/L) in 60% and CYFRA 21-1 (>2.2 microg/L) in 46% of patients. For all patients, disease-free survival (DFS) was better after combined treatment (67% vs. 43%, p < 0.0005). For patients with elevated baseline SCC antigen, DFS was better after combination therapy (67% vs. 27%, p = 0.001) which resulted more frequently in a normal SCC antigen (93% vs. 65%, p = 0.004). In contrast, in those with a normal baseline CYFRA 21-1, combined therapy resulted in a better DFS (p = 0.04). Patients who achieved a normal SCC antigen or CYFRA 21-1 after treatment had a better DFS (respectively 63 vs. 17% and 64 vs. 30%). Elevated SCC antigen posttreatment indicated residual tumor in 11/12 patients (92%), elevated CYFRA 21-1 in 7/10 patients (70%). Forty-seven patients had a tumor recurrence. At recurrence, SCC antigen was raised in 70% and CYFRA 21-1 in 69%. CONCLUSIONS: In patients with an elevated pretreatment SCC antigen, SCC antigen normalized more frequently with combined treatment and those patients had a better DFS. Elevated SCC antigen or CYFRA 21-1 levels after treatment completion indicated residual tumor in respectively 92% and 70%. The presence of elevated posttreatment levels of SCC antigen or CYFRA 21-1 indicates the need for additional salvage surgery. SCC antigen proved to be superior to CYFRA 21-1 in predicting DFS and disease recurrence.

Adult↗

Tryptophan as a link between psychopathology and somatic states.

OBJECTIVE: Several somatic illnesses are associated with psychiatric comorbidity. Evidence is provided that availability of the essential amino acid tryptophan, which is the precursor of serotonin, may cause this phenomenon. METHODS: We performed a database search to find relevant articles published between 1966 and 2002. For our search strategy, we combined several diseases from the categories hormonal, gastrointestinal, and inflammatory with the search terms "tryptophan" and "serotonin." RESULTS: The catabolism of tryptophan is stimulated under the influence of stress, hormones and inflammation by the induction of the enzymes tryptophan pyrrolase (in the liver) and IDO (ubiquitous). Because of the reduction in blood levels of tryptophan under these circumstances the formation of cerebral serotonin is decreased. CONCLUSIONS: It is argued that the coupling of peripheral tryptophan levels and cerebral serotonin levels has physiological significance. The clinical implications and therapeutic consequences of changes in tryptophan and consequently serotonin metabolism are discussed.

Animals↗