Biomedical subjects

A A Hart

Publications and source records attributed to A A Hart.

At least 55 records · Page 3Linked to original sources

PubMed1998

Low predictive value of intrinsic fibroblast radiosensitivity for fibrosis development following radiotherapy for breast cancer.

PURPOSE: To test whether the intrinsic radiosensitivity of skin fibroblasts from breast cancer patients correlates with the degree of breast fibrosis after breast conserving therapy. METHODS: In a systematic study design, 79 patients were selected from an earlier study group of 385 patients based on observed fibrosis and seven identified clinical risk factors for fibrosis development. In vitro radiosensitivity of patients' dermal fibroblasts was determined by clonogenic assay of early passage cultures. Survival was determined after irradiation at 0, 2 and 4 Gy, given in two fractions of 2 Gy with a 6 h interval. RESULTS: There was a significant inter-patient variation for SF2 values (coefficient of variation = 40%). The ratio of SF2 values for fibroblasts from patients with breast fibrosis versus those without was 0.80 (95% CI: 0.60-1.07). This was a statistically non-significant trend (p = 0.13). The same ratio for a derived value for SF2 ((SF2 + square root of SF4)/2) was 0.88 (p = 0.19). CONCLUSIONS: A significant variation in intrinsic radiosensitivity of breast cancer patients' dermal fibroblasts was observed. However, the degree of radiosensitivity did not show a significant correlation with fibrosis development. This indicates that the use of fibroblast radiosensitivity will have a limited usefulness for predicting fibrosis following breast irradiation.

Age Factors↗

PubMed1998

Do mucin-secreting squamous cell carcinomas of the uterine cervix metastasize more frequently to pelvic lymph nodes? A case-control study?

Twenty-nine patients with stage IB/IIA squamous cell carcinoma of the uterine cervix who had positive pelvic nodes were matched with 29 cases of node-negative squamous cell carcinoma by depth of invasion and lymphovascular space invasion. By multivariate analysis, these criteria independently predicted pelvic node metastases. Intracellular mucin, demonstrated by alcian-blue staining at pH 2.5, was noted in 21 of the 58 patients (36%). The frequency of mucin-positive tumors was not significantly different between the patients and their controls (38 versus 34%, p = 0.78), nor was the degree of positivity. These results suggest that, although a substantial proportion of squamous cell carcinomas exhibit mucin secretion, patients with these tumors are not at increased risk for pelvic node metastases. We therefore do not recommend routine mucin staining in cervical squamous cell carcinomas.

Adult↗

PubMed1998

Marfan syndrome in children and adolescents: an adjusted nomogram for screening aortic root dilatation.

OBJECTIVE: To construct an adjusted nomogram for the echocardiographic screening of aortic root diameter in children with possible Marfan disease. DESIGN: In 91 children (42 boys, 49 girls, age range 3.2 to 18.4 years) undergoing Marfan screening from 1983 until 1996, the diagnosis Marfan syndrome and any other aortic pathology was definitely ruled out. These served as a control population to set appropriate reference standards. RESULTS: Compared with a standard Dutch reference population, body surface area of the control subjects (mean (SD)) was above the 50th centile (boys 0.09 (0.20) m2, range -0.28 to 0.69 m2; girls 0.09 (0.17) m2, range -0.17 to 0.69 m2). Echocardiographically determined aortic root diameter and body surface area showed a linear relation and a greater variability of aortic root diameter in these relatively tall subjects (n = 91, R2 = 0.62) than in the standard nomogram (n = 56, R2 = 0.93). In 24% of cases (n = 22), the aortic root exceeded the upper limit of normal in the standard nomogram, by 2.2 (2.0) mm. An adjusted nomogram was constructed with a higher upper limit. CONCLUSIONS: A Marfan screening population differs from the unselected population in body surface area and aortic root size variability. An adjusted nomogram should therefore be used to detect a truly enlarged aortic root.

Adolescent↗

PubMed1998

Marfan syndrome in children and adolescents: predictive and prognostic value of aortic root growth for screening for aortic complications.

OBJECTIVE: To assess and measure the diagnostic and prognostic value of individual aortic root growth in children and adolescents with Marfan syndrome. DESIGN: From 1983 to 1996, 250 children were screened for Marfan syndrome. Serial echocardiographic aortic root measurements of 123 children (57 Marfan, 66 control) were available for evaluation of aortic root growth. Aortic root diameters were correlated with body surface area. Based on individual growth of the aortic root a discrimination formula was derived to distinguish Marfan patients from control subjects. RESULTS: Sensitivity and specificity of this method, which were dependent on the number of measurements, were 84% and 73%, respectively, for three serial measurements. The discrimination score also predicted a five year complication free survival in all patients. CONCLUSIONS: In children and adolescents with Marfan syndrome, aortic root growth differs significantly from subjects in whom Marfan syndrome was definitely ruled out during screening. Measurement of individual aortic root growth may serve to establish diagnosis at an early stage and is of prognostic value for occurrence of aortic complications.

Adolescent↗

PubMed1997

[Nasopharyngeal carcinoma: epidemiology and treatment outcome].

OBJECTIVE: To determine epidemiology, symptoms and treatment results of patients with nasopharyngeal carcinoma. DESIGN: Descriptive and retrospective. SETTING: The Dutch Cancer Institute (Antoni van Leeuwenhoek Hospital), Amsterdam, the Netherlands. METHODS: The clinical, epidemiological and radiotherapy data of the 129 patients with a nasopharyngeal carcinoma referred between 1977 and 1993 to our hospital were analysed. Twenty patients were referred for a second opinion only, presented with recurrent disease, or had received their treatment elsewhere. Data of 109 patients were analysed. RESULTS: During the last decade more patients born in Asia and North-Africa were referred (p = 0.0057), a total of 52 (48%) out of 109 referred patients. There were 62 (58%) patients in whom an enlarged cervical lymph node at level II (upper jugular group) was the presenting symptom. In 53 (50%) cases hearing loss due to otitis media with effusion was the first symptom. In 54 (54%) patients the delay between the first symptoms and diagnosis of carcinoma was > 20 weeks. 5-year survival was 48% (SE 6%) for the whole group (n = 109) of patients and 52% (SE 6%) for the patients treated with curative intent (n = 96). CONCLUSION: During the last decade the population of patients with nasopharyngeal carcinoma in the Netherlands contained more patients from Asia and North-Africa. Suspicious cervical lymph node swellings and (or) (unilateral) otitis media with effusion may be indicative of a nasopharyngeal carcinoma.

Adolescent↗

PubMed1997

Surgical pathologic factors that predict recurrence in stage IB and IIA cervical carcinoma patients with negative pelvic lymph nodes.

BACKGROUND: The purpose of this analysis was to identify pathologic risk factors for recurrence and patterns of recurrence in patients with International Federation of Gynecology and Obstetrics Stage IB and IIA cervical carcinoma and negative pelvic lymph nodes after radical hysterectomy. METHODS: During the period 1982-1991, 271 clinically staged patients with Stage IB or IIA cervical carcinoma underwent a Wertheim-Okabayashi radical hysterectomy with pelvic lymph node dissection. The study group was composed of 196 lymph node negative patients. Pathology slides were reviewed and multivariate analysis performed to identify independent prognostic factors. RESULTS: The recurrence rate in the study group was 7.7%. In multivariate analysis, the following factors were identified as independent risk factors for recurrence: adenocarcinoma (P = 0.003), depth of invasion as a fraction of tumor penetration of the cervical stroma (P = 0.01), and an extensive stromal inflammatory cell infiltrate (P = 0.04). Based on these factors, the following risk groups were identified: a low risk group (N = 140, 5-year disease free interval [DFI] = 97%) and a high risk group (N = 55, 5-year DFI = 81%). An evaluation of the recurrence patterns for these patients showed a predominance of pelvic recurrences. CONCLUSIONS: This study showed that among patients with Stage IB and IIA cervical carcinoma and negative pelvic lymph nodes, a subset with a significant risk for recurrence could be identified. Because the majority of recurrences in the lymph node negative group were pelvic recurrences, the value of adjuvant radiotherapy as a treatment for selected lymph node negative patients should be evaluated in a prospective study.

Adenocarcinoma↗

PubMed1997

The Bax alpha:Bcl-2 ratio modulates the response to dexamethasone in leukaemic cells and is highly variable in childhood acute leukaemia.

Bcl-2 over-expression has been shown to inhibit apoptosis induced by a variety of stimuli, whereas a predominance of Bax alpha to Bcl-2 accelerates apoptosis upon apoptotic stimuli. We sought to study the relevance of these apoptotic regulating gene products in leukaemia. In a panel of leukaemia and lymphoma cell lines (HL60, DoHH2, CEM C7, L1210 and S49), the Bax alpha-to-Bcl-2 ratio as assessed by Western-blot analysis correlated with sensitivity to dexamethasone treatment. In addition, in HAbax alpha-transfected CEM C7 clones, a similar correlation was found for dexamethasone and thapsigargin sensitivity. In bone-marrow aspirates from patients with childhood acute lymphoblastic or myelocytic leukaemia (ALL, n = 48; AML, n = 8), the Bcl-2 and Bax alpha levels were highly variable, but well within the range found in the Bax alpha transfectants and in the established cell lines. Bcl-2 levels were lower in T- than in B-lineage ALL, which could be ascribed to simultaneous inverse relation between Bcl-2 and WBC. By contrast, Bax alpha:Bcl-2 was independent of any presenting feature and was largely dependent on Bax alpha levels. Results suggest that Bax alpha:Bcl-2, rather than Bcl-2 alone is important for the survival of drug-induced apoptosis in leukemic cell lines and ALL.

Apoptosis↗

PubMed1997

IL-2-induced proliferative response is controlled by loci Cinda1 and Cinda2 on mouse chromosomes 11 and 12: a distinct control of the response induced by different IL-2 concentrations.

Lymphocytes of mouse strains BALB/cHeA (BALB/c) and STS/A (STS) differ in the IL-2-induced proliferative response, STS being a high and BALB/c a low responder in the range of concentrations 125-2000 IE/ml. We analyzed the genetic basis of this strain difference using the recombinant congenic (RC) strains of the BALB/c-c-STS/Dem (CcS/Dem) series. This series comprises 20 homozygous strains all derived from two parental inbred strains: the "background" strain BALB/c and the "donor" strain STS. Each CcS/Dem strain contains a different, random set of approximately 12.5% genes of the donor strain STS and approximately 87.5% genes of the background strain BALB/c. In this way, the STS genes controlling the IL-2-induced response became separated into individual CcS/Dem strains, as indicated by differences in the magnitude of the IL-2-induced response among CcS/Dem strains (M. Lipoldová et al., 1995, Immunogenetics 41: 301-311). To map some of these genes, we tested F2 hybrids between one of the high-responder RC strains, CcS-4, and the low-responder parental strain BALB/c. We found that the response to high IL-2 concentrations is controlled by a locus, Cinda1 (cytokine-induced activation 1), on chromosome 11 near the marker D11Mit4. The response to a lower dose of IL-2 tested on lymphocytes of the same mice was found to be controlled by another locus, Cinda2, in the centromeric part of chromosome 12, the higher response being linked to the STS allele of the marker D12Mit37. Understanding the action of genetic factors, such as Cinda1 and Cinda2, that control T cell function is expected to contribute to the efficient analysis of the genetic control of susceptibility to infections and autoimmune diseases.

Alleles↗

PubMed1997

Overexpression of cyclin D1 indicates a poor prognosis in squamous cell carcinoma of the head and neck.

OBJECTIVES: To evaluate the overexpression of cyclin D1 and p53 as a prognostic marker of squamous cell carcinoma of the head and neck and to investigate whether deregulation of these genes is associated with an unfavorable course of disease. DESIGN: Retrospective study. MATERIALS AND METHODS: Formalin-fixed, paraffin-embedded tumor materials that were obtained from a well-characterized series of 115 patients with resectable head and neck cancer at The Netherlands Cancer Institute, Amsterdam, were analyzed by immunohistochemical methods using antiserum samples that were directed against 2 proteins (ie, cyclin D1 and p53), which are crucial in the regulation of the G1 phase of the cell cycle. RESULTS: Overexpression of cyclin D1 protein was found in 49% of the patients with squamous cell carcinoma of the head and neck. This overexpression was not associated with known prognostic factors (eg, the T and N stages). Tumors recurred more frequently and in a shorter period in patients whose primary tumors showed an overexpression of cyclin D1 protein. This difference (P = .05) was statistically significant in a stepwise proportional hazard regression analysis. However, since a discrepancy in staining results was observed between the biopsy and resection materials that were taken from the same patient, this result may not have been applicable in the evaluation of biopsy specimens only. This discrepancy is most likely owing to tissue heterogeneity. The overexpression of p53 that was found in 42% of the patients was of no prognostic significance. CONCLUSIONS: These data provide evidence that overexpression of cyclin D1 protein in resection material of squamous cell carcinomas of the head and neck is indicative of a poor prognosis, independently of other known prognostic factors. Whether overexpression of cyclin D1 may therefore be used to select patients for more intensive treatment should be examined in the context of a clinical trial.

Adult↗

PubMed1997

Density gradient isoelectric focusing of proteins in artificial pH gradients made up of binary mixtures of amphoteric buffers.

A density gradient electrophoresis apparatus made of Perspex (7 cm, O 2.2 cm) with a circular platinum anode and a palladium cathode was used for the separation of proteins in free liquid. Following a concept developed by M. Bier et al. (Electrophoresis 1993, 14, 1011-1018), mixtures of two suitable amphoteric buffers I and II provide for media with a fixed and electrophoretically stable pH or were used for the generation of preformed (electrophoretically stable) pH gradients covering about 1 pH unit. Amphoters I and II are considered suitable if there is overlap between (pK(1,1)-1-2) and the pK(2,II)+1+2) region. 3-(N-Morpholino)propanesulfonic acid (MOPS) and gamma-amino-n-butyric acid (GABA) were used as an example. Two approaches were followed: (i) rate-zonal separation of test proteins in a pH window, formed by a fixed ratio of MOPS/GABA. (ii) Isoelectric focusing in a shallow preformed pH gradient, made up of inverse reciprocal linear gradients of MOPS and GABA. At isopH, test proteins (bovine serum albumin, cytochrome c, ferritin, hemoglobin, lactoglobulin, myoglobin, and transferrin) were rate-zonally separated within a short time. Even the separation of the A and B forms of lactoglobulin was feasible at isopH. The glycoforms of transferrin were separated and enriched on a pH 5.2-6.1 pH gradient, indicating that pH differences of about 0.01 still permit resolution. Contrary to the ill-defined Ampholines, the cost of these well-defined amphoters is low.

Buffers↗

PubMed1997

Identification of high-risk groups among node-positive patients with stage IB and IIA cervical carcinoma.

The purpose of the present study was to identify a subset of high-risk patients among surgically treated node-positive patients with stage IB and IIA cervical carcinoma. From 1982 through 1991, 334 patients underwent radical hysterectomy for FIGO stage IB and IIA cervical carcinoma. In 68 patients pathological analysis of the surgical specimen revealed positive pelvic nodes. In this group, a Cox proportional hazard analysis was performed to examine the prognostic significance of clinicopathological variables. Only for adenocarcinoma (P = 0.002) and parametrium infiltration (P = 0.003) was evidence of an association with prognosis found. Based on these two factors, patients with positive pelvic nodes were categorized into a low-risk group (squamous cell carcinoma without parametrium infiltration, N = 33) and a high-risk group (squamous cell carcinoma with parametrium infiltration or adenocarcinoma, N = 34). The 5-year disease-specific survival in the low-risk group was 94% compared with 60% in the high-risk group (P = 0.003). For patients in the high-risk group, there is an urgent need for alternative adjuvant treatment to improve outcome.

Adenocarcinoma↗

PubMed1997

A retrospective study of the hearing results obtained after stapedotomy by the implantation of two Teflon pistons with a different diameter.

This study reports the evaluation of hearing results after implantation of a Teflon piston of a different diameter in cases of otosclerosis requiring stapedotomy. By random selection, a Teflon piston with a shaft diameter of 0.3 mm was inserted in 34 cases and a piston with a shaft diameter of 0.4 mm in 26 cases. A retrospective analysis of the pre- and postsurgery audiological results of these two patient groups was carried out by microcomputer. A repeated statistical measures analysis of variance was used to test and estimate the air-conduction frequency-specific differences between the two prostheses with respect to changes in pre- and postoperative healing. The results of this comparative study of the two Teflon pistons with different diameters indicate statistically a greater hearing gain for the 0.4-mm prosthesis, especially in the lower frequencies.

Adult↗

PubMed1997

Simulation of the distribution of parental strains' genomes in RC strains of mice.

Recombinant Congenic strains (RC strains) were developed to facilitate mapping of genes influencing complex traits controlled by multiple genes. They were produced by inbreeding of the progeny derived from a second backcross from a common 'donor' inbred strain to a common 'background' inbred strain. Each RC strain contains a random subset of approximately 12.5% of genes from the donor strain and 87.5% of genes from the background strain. In this way the genetic control of a complex disease may be dissected into its individual components. We simulated the production of the RC strains to study to what extent they have to be characterized in order to obtain sufficient information about the distribution of the parental strains' genomes in these strains and to acquire insight into parameters influencing their effectiveness in mapping quantitative trait loci (QTLs). The donor strain genome in the RC strains is fragmented into many segments. Genetic characterization of these strains with one polymorphic marker per 3.3 centiMorgans (cM) is needed to detect 95% of the donor strain genome. The probability of a donor strain segment being located entirely in between two markers of background strain origin that are 3 cM apart (and hence escaping detection) is 0.003. Although the donor strain genome in the RC strains is split into many segments, the largest part still occurs in relatively long stretches that are mostly concentrated in fewer than 13 autosomes, the median being 9 autosomes. Thus, in mapping QTLs, the use of RC strains facilitates the detection of linkage.

Animals↗

PubMed1997

Treatment and outcome of brain metastasis as first site of distant metastasis from breast cancer.

Twenty-eight consecutive patients with breast cancer were analyzed who presented with a single brain metastasis as first site of distant metastasis. The response to surgery with postoperative radiation therapy (RT) (9 patients) and to non-surgical therapy as first-line treatment was 100% and 89% respectively with a significant difference in median recurrence-free intervals of 23 months and of 5 months respectively (p = 0.033). Retreatment of a local relapse by surgery (+/-RT, +/-chemotherapy) or by non-surgical treatment resulted in a response in 6 of the 7 operated patients and in 5 of the 6 non-operated patients with a median duration of response of 7 months (range 2-20 months) and of 3 months (range 2-4 months) respectively. The overall median survival of the 28 patients with a single brain metastasis was 16 months (range 2-39 months). The median survival in the primarily operated patients was 23 months, in the primarily not-operated group 10 months, and in the never-operated group 9 months. In comparison, the response to non-surgical treatment in 20 consecutive patients who presented with multiple brain metastases as first site of distant metastasis was 55% with a median recurrence free interval of 4 months. The median survival in this group was 4 months, which was significantly shorter than survival of patients with single brain metastasis (p = 0.0036). These results suggest that breast cancer patients with a single brain metastasis as first presentation of relapse constitute a specific subgroup with a favorable response to treatment and a long survival especially if they can be treated by surgery with postoperative RT.

Adult↗

PubMed1997

Topical dinitrochlorobenzene combined with systemic dacarbazine in the treatment of recurrent melanoma.

Fifty-nine selected patients with recurrent melanoma (37 locoregional and 22 locoregional and haematogenic) were treated with a combination of topical dinitrochlorobenzene (DNCB) and systemic dacarbazine (DTIC). The observations were analysed retrospectively. Fifteen patients (25%) (one third with distant spread) experienced a complete response, with a median duration of 10 months (range 3-210 months). Five of these patients, three of them with haematogenic disease, showed prolonged disease-free survival (85, 156, 170, 177 and 210 months). Seven patients (12%) obtained a partial response, and no response was seen in the remaining 37 patients (63%). In the presence of a severe local reaction to topical DNCB application the median survival was 12 months compared with 7 months in cases with a slight or moderate local reaction (P=0.0013). Patients showing a response to the DNCB-DTIC combination had a median survival of 18 months versus 7 months for the non-responders (P<0.0003). In view of the prolonged survival in five patients, this combined treatment schedule yields promising results in the treatment of selected melanoma patients with cutaneous recurrences, whether or not these are associated with other metastases.

Administration, Topical↗

PubMed1997

Nedocromil sodium in obstructive airways disease: effect on symptoms and plasma protein leakage in sputum.

In patients with asthma or chronic obstructive pulmonary disease, there is chronic airway inflammation with increased leakage of plasma proteins into the airway lumen, which can be reduced by inhaled glucocorticosteroids. Nedocromil sodium is an anti-inflammatory drug, and we questioned whether it also affects the leakage of plasma proteins. In a double-blind placebo-controlled study we investigated the effect of 12 weeks of treatment with nedocromil on forced expiratory volume in one second (FEV1), provocative concentration of histamine causing a 20% fall in FEV1 (PC20), peak flow, symptom scores, and plasma protein leakage in sputum, in 31 patients with obstructive airways disease and sputum production (mean (range) FEV1 61% of predicted (42-87%); geometric mean (range) PC20 0.39 (0.04-2.9) mg x mL(-1)). As a measure for plasma protein leakage we calculated the relative coefficients of excretion (RCE) of proteins from serum to the soluble phase of sputum. There was a small increase in morning and evening peak flow (p<0.05) and a decrease in night-time bronchodilator use (p<0.02) in favour of nedocromil. The RCE of alpha2-macroglobulin to albumin significantly decreased after treatment with nedocromil (p=0.03). The results show limited clinical efficacy of nedocromil in our study group. They further suggest that the anti-inflammatory properties of nedocromil extend to inhibition of plasma protein leakage into the airways.

Anti-Inflammatory Agents↗

PubMed1997

Persisting Haemophilus influenzae strains induce lower levels of interleukin-6 and interleukin-8 in H292 lung epithelial cells than nonpersisting strains.

Nonencapsulated Haemophilus influenzae strains isolated from patients with chronic bronchitis can be divided into those that persist in the lower respiratory tract and those that do not. We tested the hypothesis that persisting and nonpersisting strains differ in the extent to which they activate epithelial cells to produce two potent inflammatory mediators, interleukin (IL)-6 and IL-8. A suspension of 10(7) and 10(8) colony forming units (cfu) x mL(-1) of H. influenzae, persisting and nonpersisting, induced a dose- and time-dependent production of IL-6 and IL-8 by the human pulmonary mucoepidermoid carcinoma-derived cell line H292, but levels of IL-6 were lower after exposure to persisting H. influenzae (p<0.05). IL-8 production showed a similar trend (p<0.02; analysis of variance). H. influenzae bacteria that adhered to H292 cells were equally distributed over persisting and nonpersisting isolates and induced IL-6 and IL-8 levels similar to their nonadhering counterparts. The difference between persisting and nonpersisting H. influenzae was not due to cytotoxic, antimetabolic or antiproliferative effects on H292 cells. Furthermore, pre-exposure of cells to persisting and nonpersisting isolates did not block subsequent IL-1beta-induced IL-6 production. We conclude that persisting clinical isolates induce less interleukin-6 and interleukin-8 in H292 cells than nonpersisting isolates, probably because they excrete lower amounts of a stimulus of H292 cells. The stimulus is heat stable, hydrophilic and nonproteinous and probably not lipopolysaccharide alone. These findings support the suggestion that some strains of Haemophilus influenzae that persist in the airways of patients, may do so because they induce only a weak inflammatory response.

Analysis of Variance↗

PubMed1997

Vasopressin and oxytocin levels during normal pregnancy: effects of chronic dietary sodium restriction.

Neurohypophysial hormones are thought to be involved in alterations in fluid balance during pregnancy and delivery. In the course of normal pregnancy intravascular volume is increased whereas sodium restriction is thought to reduce plasma volume and cardiac output. In the present study, we measured the effect of long-term severe sodium restriction on vasopressin (AVP) and oxytocin (OT) levels during normal pregnancy and after delivery. Fifty-nine healthy nulliparous women were randomized either for a low sodium diet (20 mmol sodium daily) or for a normal diet from week 12 of pregnancy onwards. Circulating plasma levels and urinary excretion of AVP and OT, their neurophysins (Np-AVP and Np-OT) and AVP bound to platelets were determined at regular intervals during pregnancy and after delivery. After completion of the study, women on a sodium-restricted diet were compared with control women on a normal diet using repeated measurement ANOVA with adjustment for potentially confounding variables. After randomization, a reduction in urinary sodium excretion of, on average, 40-82% was found. In general, no effect of sodium restriction could be demonstrated on the various parameters (0.53 < P < 0.98) with the exception of a significantly lower 24-h urinary AVP excretion by non-smokers with sodium restriction compared with non-smokers having a normal diet (P = 0.018). For all parameters, clear changes were found in the course of pregnancy and puerperium (P < 0.0001 to P < 0.005). Platelet-bound AVP decreased and Np-OT increased during pregnancy. After birth, free plasma AVP, platelet-bound AVP, OT, osmolality, sodium and potassium increased, while Np-AVP and Np-OT decreased. Although elevated Np-AVP and Np-OT levels during pregnancy seem to indicate increased release of neurohypophysial hormones, pregnancy up to 36 weeks of gestation is accompanied by low circulating AVP and OT levels. Long-term severe sodium restriction diminishes urinary AVP excretion in (non-smoking) pregnant women, without changing circulating levels of AVP and OT, despite the known reduction in circulating volume. The reduced circulating (platelet-bound) AVP levels during pregnancy, whether or not in combination with severe sodium restriction, support the absence of significant non-osmotic stimulation of AVP during pregnancy.

Adult↗