ABSTRACT
BACKGROUND: High-grade anal intraepithelial squamous lesion is significantly prevalent among men who have sex with men and are infected with the human immunodeficiency virus (HIV). This condition-the precursor to anal cancer-significantly increases the risk of developing it. Conversely, low-grade anal intraepithelial squamous typically follow a benign course and usually regress spontaneously. MATERIALS AND METHODS: To describe a population of men who have sex with men living with HIV followed in a specialized anal cancer screening unit we conducted an observational, retrospective, and single-center study. RESULTS: Ninety-four patients were analyzed, with a mean age of 39±9 years, and a 87% positivity rate for high-risk human papillomavirus (HR-HPV). At the initial visit, 47% presented with low-grade squamous intraepithelial lesions. The progression rate to high-grade squamous intraepithelial lesion was 37.2 per 100,000 patients/year. None of the patients developed anal cancer. Tobacco and alcohol consumption were associated with this progression. DISCUSSION: In this series, longer duration of HIV infection, tobacco and alcohol use and the presence of HR-HPV were significantly associated with the occurrence of high-grade intraepithelial lesions. A lower risk of progression was seen in patients with higher education. CONCLUSION: In men who have sex with men living with HIV, the association of factors such as smoking, alcohol, the presence of HR-HPV and an increased burden of human papillomavirus disease makes these patients more susceptible to develop high-grade anal squamous lesions.
ABSTRACT
BACKGROUND: High-grade anal intraepithelial squamous lesion is significantly prevalent among men who have sex with men and are infected with the human immunodeficiency virus (HIV). This condition-the precursor to anal cancer-significantly increases the risk of developing it. Conversely, low-grade anal intraepithelial squamous typically follow a benign course and usually regress spontaneously. MATERIALS AND METHODS: To describe a population of men who have sex with men living with HIV followed in a specialized anal cancer screening unit we conducted an observational, retrospective, and single-center study. RESULTS: Ninety-four patients were analyzed, with a mean age of 39±9 years, and a 87% positivity rate for high-risk human papillomavirus (HR-HPV). At the initial visit, 47% presented with low-grade squamous intraepithelial lesions. The progression rate to high-grade squamous intraepithelial lesion was 37.2 per 100,000 patients/year. None of the patients developed anal cancer. Tobacco and alcohol consumption were associated with this progression. DISCUSSION: In this series, longer duration of HIV infection, tobacco and alcohol use and the presence of HR-HPV were significantly associated with the occurrence of high-grade intraepithelial lesions. A lower risk of progression was seen in patients with higher education. CONCLUSION: In men who have sex with men living with HIV, the association of factors such as smoking, alcohol, the presence of HR-HPV and an increased burden of human papillomavirus disease makes these patients more susceptible to develop high-grade anal squamous lesions.
ABSTRACT
Trinidad and Tobago, a neotropical country, has 38 reported chigger species. Of these species, 18 were parasitizing bats. Here, we describe a new genus and species parasitizing a ghost-faced bat in this country.
Subject(s)
Caves , Chiroptera , Trombiculiasis , Trombiculidae , Animals , Chiroptera/parasitology , Species Specificity , Trinidad and Tobago , Trombiculiasis/parasitology , Trombiculidae/classificationABSTRACT
OBJECTIVES: To determine whether circulating gelsolin (GSN) levels in patients with ankylosing spondylitis (AS) undergoing TNF-α antagonist-infliximab-therapy are altered compared with controls and to establish whether disease activity, systemic inflammation and metabolic syndrome are potential determinants of circulating GSN levels in these patients. METHODS: We assessed GSN serum concentrations in a series of 30 non-diabetic AS patients without cardiovascular (CV) disease undergoing TNF-α antagonist-infliximab therapy and 48 matched controls. GSN levels were measured immediately before and after an infliximab infusion. Correlations of GSN serum levels with disease activity, systemic inflammation and metabolic syndrome were assessed. Potential changes in GSN concentration following an infusion of anti-TNF-α monoclonal antibody-infliximab were also analysed. RESULTS: Although at the time of the study AS patients undergoing anti-TNF-α therapy had adequate control of the disease (mean BASDAI 2.94), they showed lower GSN serum levels than healthy controls (mean±SD: 38660.42±23624.6 ng/ml versus 68975.43±31246.79 ng/ml; p<0.0001). When AS patients were stratified according to sex, we observed that GSN levels were significantly lower in men than in women (p=0.032). However, no differences in GSN levels according to the specific clinical features of the disease were seen. No association was found between GSN concentration and adipokines or biomarkers of endothelial cell activation. However, correlation between basal GSN levels and insulin resistance was observed. A single infliximab infusion did not lead to significant changes in GSN levels. CONCLUSIONS: GSN concentration is reduced in AS patients undergoing periodical anti-TNF-α therapy and low disease activity. Potential association with some metabolic syndrome features seems to exist.
Subject(s)
Antibodies, Monoclonal , Gelsolin/metabolism , Spondylitis, Ankylosing , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adipokines/metabolism , Adult , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antirheumatic Agents/administration & dosage , Antirheumatic Agents/adverse effects , Dose-Response Relationship, Drug , Drug Monitoring , Female , Humans , Inflammation/drug therapy , Infliximab , Infusions, Intravenous , Male , Metabolism/drug effects , Middle Aged , Outpatients , Patient Acuity , Sex Factors , Spondylitis, Ankylosing/drug therapy , Spondylitis, Ankylosing/metabolism , Spondylitis, Ankylosing/physiopathology , Statistics as Topic , Treatment OutcomeABSTRACT
OBJECTIVES: To determine whether circulating osteopontin (OPN) levels in patients with ankylosing spondylitis (AS) undergoing TNF-α antagonist-infliximab-therapy are increased compared with controls and to establish whether disease activity, systemic inflammation, metabolic syndrome, adipokines and biomarkers of atherosclerosis are potential determinants of circulating OPN levels in these patients. METHODS: We assessed OPN serum concentrations in a series of 30 non-diabetic AS patients without cardiovascular disease undergoing TNF-α antagonist-infliximab therapy and 48 matched controls. OPN levels were measured immediately before and after an infliximab infusion, at time 0 and at time 120 minutes respectively. Correlations of OPN serum levels with clinical features, disease activity, systemic inflammation, metabolic syndrome and several biomarkers of atherosclerosis were assessed. Potential changes in OPN concentration following an infusion of anti-TNF-α monoclonal antibody-infliximab were also analysed. RESULTS: At the time of the study AS patients undergoing anti-TNF-α therapy had low disease activity (mean BASDAI 2.94) and they showed similar OPN serum levels to healthy controls. No differences in OPN levels according to the specific clinical features of the disease were seen. Also, no correlation between OPN concentration and insulin resistance and adipokines was observed. However, a positive correlation between OPN and angiopoietin-2 (Angpt-2) serum levels was found (r=0.397; p=0.04). In addition, a single infliximab infusion led to a marginal statistically significant reduction in OPN levels (24112.19±14608.73 pg/ml at time 0 versus 21806.62±11390.83 pg/ml at time 120'; p=0.05). CONCLUSIONS: OPN and Angpt-2 serum levels are correlated in non-diabetic AS patients undergoing TNF-α antagonist therapy.
Subject(s)
Angiopoietin-2/blood , Antibodies, Monoclonal , Atherosclerosis , Osteopontin/blood , Spondylitis, Ankylosing , Tumor Necrosis Factor-alpha/antagonists & inhibitors , Adult , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antirheumatic Agents/administration & dosage , Antirheumatic Agents/adverse effects , Atherosclerosis/diagnosis , Atherosclerosis/epidemiology , Atherosclerosis/etiology , Atherosclerosis/metabolism , Biomarkers/blood , Cardiovascular Diseases/epidemiology , Cardiovascular Diseases/prevention & control , Female , Humans , Infliximab , Male , Metabolism/drug effects , Middle Aged , Outpatients , Risk Factors , Spain , Spondylitis, Ankylosing/complications , Spondylitis, Ankylosing/drug therapy , Spondylitis, Ankylosing/metabolism , Statistics as Topic , Treatment OutcomeABSTRACT
Henoch-Schönlein purpura (HSP) is the most common type of primary small-sized blood vessel vasculitis in children and an uncommon condition in adults. Interleukin (IL)-6 is a proinflammatory cytokine whose effect is controlled by the IL-6 receptor (IL-6R). IL-6 transducer (IL-6ST/gp130) is the signal-transducing subunit of the IL-6R. Two hundred and eighty five Spanish HSP patients and 877 sex and ethnically matched controls were genotyped for the IL6R rs2228145 and IL6ST/gp130 rs2228044 functional polymorphisms. No significant differences in the genotype and allele frequencies between HSP patients and controls were observed. Moreover, there were no differences between HSP patients according to the age at disease onset, presence of nephritis or gastrointestinal manifestations. Our results do not confirm association of IL6R rs2228145 and IL6ST/gp130 rs2228044 polymorphisms with HSP.
Subject(s)
Cytokine Receptor gp130/genetics , Genetic Predisposition to Disease , IgA Vasculitis/genetics , Receptors, Interleukin-6/genetics , Adult , Child , Disease Progression , Female , Gene Frequency , Genetic Association Studies , Genotype , Humans , IgA Vasculitis/immunology , Male , Polymorphism, Genetic , SpainABSTRACT
Tuckerella japonica Ehara appears strongly associated with tea (Camellia sinensis (L.) Kuntze, Theaceae) and, due to certain cultural practices in tea production, has in fact become a world traveller, accompanying the greatly coveted tea plant as it spread across the planet. The history of tea production and culture, and its arrival in the USA, provides the backdrop for this traveller's tale. Tuckerella japonica is morphologically similar to T. flabellifera Miller, described from Tasmania in Australia from Bedfordia salicina (Labill.) D.G. (Asteraceae). These two species have historically been misidentified as each other, creating inaccuracies in the collection records. The implications of this in terms of host plant lists and world distribution are discussed further, along with their morphological separation. The male and immature stages of T. japonica are described for the first time. Tuckerella xinglongensis Lin and Fu, from tea in China, is considered a junior synonym of T. japonica. The loss of the ancestral prostigmatan condition of three nymphal stages during ontogeny is confirmed for males of T. flabellifera, which do not retain a tritonymphal stage.
Subject(s)
Camellia sinensis , Mites/ultrastructure , Tea/history , Animals , Female , History, 18th Century , History, 19th Century , History, 20th Century , History, Ancient , Male , Mites/classification , Mites/physiologyABSTRACT
The genus Raoiella is best known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This paper attempts to address some of the basic historical questions regarding the palm mite as well as the genus. Molecular characters from COI and 28S regions were used to produce a phylogenetic hypothesis for the genus in an effort to understand its geographic origin. It also uses COI barcode data to delimit several potentially new species discovered by the authors in Australia. Results show a basal split between R. indica and all other Raoiella species, which indicates Africa or the Middle East as the most probable origin of the genus. Additionally, COI data suggests that at least eight new species are represented among the 20 Australian populations included in this study.
Subject(s)
Biodiversity , Introduced Species , Mites/classification , Phylogeny , Animals , Australia , DNA, Ribosomal/chemistry , Electron Transport Complex IV/genetics , Mites/genetics , RNA, Ribosomal, 28S/genetics , Sequence Analysis, DNAABSTRACT
The use of low-temperature scanning electron microscopy (LTSEM) to study external mouthpart morphology in the Tenuipalpidae, in particular the genus Raoiella, has brought some aspects of the mechanics of feeding in this group into question. In addition, an LTSEM study on the specialized feeding behaviour of Raoiella indica Hirst (Tetranychoidea: Tenuipalpidae) revealed host plant use in this species could be affected by stomatal complex morphology.
Subject(s)
Arecaceae/parasitology , Herbivory , Mites/ultrastructure , Animals , Arecaceae/ultrastructure , Female , Host-Parasite Interactions , Male , Mites/physiology , Mouth/physiology , Mouth/ultrastructure , Musa/parasitology , Musa/ultrastructure , Plant Stomata/ultrastructureABSTRACT
The role of the mango bud mite, Aceria mangiferae, in carrying conidia of Fusarium mangiferae, vectoring them into potential infection sites, and assisting fungal infection and dissemination was studied. Following the mite's exposure to a green fluorescent protein-marked isolate, conidia were observed clinging to the mite's body. Agar plugs bearing either bud mites or the pathogen were placed on leaves near the apical buds of potted mango plants. Conidia were found in bud bracts only when both mites and conidia were co-inoculated on the plant, demonstrating that the mite vectored the conidia into the apical bud. Potted mango plants were inoculated with conidia in the presence or absence of mites. Frequency and severity of infected buds were significantly higher in the presence of mites, revealing their significant role in the fungal infection process. Conidia and mite presence were monitored with traps in a diseased orchard over a 2-year period. No windborne bud mites bearing conidia were found; however, high numbers of windborne conidia were detected in the traps. These results suggest that A. mangiferae can carry and vector conidia between buds and assist in fungal penetration but does not play a role in the aerial dissemination of conidia between trees.
Subject(s)
Fusarium/physiology , Mangifera/microbiology , Mangifera/parasitology , Mites/microbiology , Plant Diseases/microbiology , Animals , Host-Parasite Interactions , Mites/ultrastructure , Spores, Fungal , Time FactorsABSTRACT
We verified infestation of Oligonychus milleri (McGregor) on plantations of Pinus caribaea (Pinaceae) and of Oligonychus ununguis (Jacobi) on plantations of Eucalyptus urophylla x Eucalyptus grandis (Myrtaceae) in State of Rondônia, Northern region of Brazil. This represents the first record of O. milleri in Brazil. Oligonychus ununguis was recorded previously, on cypress. The damage caused by these two spider mites in the plantations is described herein.
Subject(s)
Eucalyptus , Pinus , Tetranychidae , Animals , BrazilABSTRACT
In patients with portal hypertension, ectopic varices can develop at any site along the gastrointestinal tract outside the classically described gastroesophageal location. Like esophageal variceal hemorrhage, bleeding from ectopic varices can be life-threatening. Diagnosis and treatment of ectopic varices can be challenging; to date, no effective treatment algorithm has been described. A systematic teamwork approach to diagnosing and treatment of ectopic varices is required to successfully manage hemorrhage from ectopic varices.
Subject(s)
Algorithms , Disease Management , Esophageal and Gastric Varices/therapy , Gastrointestinal Hemorrhage/therapy , Hypertension, Portal/complications , Esophageal and Gastric Varices/complications , Gastrointestinal Hemorrhage/etiology , Humans , Hypertension, Portal/therapy , Ligation , Male , Middle AgedABSTRACT
beta-Mannosidosis is a lethal lysosomal storage disease inherited as an autosomal recessive in man, cattle and goats. Laboratory assay data of plasma beta-mannosidase activity represent a mixture of homozygous normal and carrier genotype distributions in a proportion determined by genotype frequency. A maximum likelihood approach employing data transformations for each genotype distribution and assuming a diallelic model of inheritance is described. Estimates of the transformation and genotype distribution parameters, gene frequency, genotype fitness and carrier probability were obtained simultaneously from a sample of 2,812 observations on U.S. purebred Salers cattle with enzyme activity, age, gender, month of pregnancy, month of testing, and parents identified. Transformations to normality were not required, estimated gene and carrier genotype frequencies of 0.074 and 0.148 were high, and the estimated relative fitness of heterozygotes was 1.36. The apparent overdominance in fitness may be due to a nonrandom sampling of progeny genotypes within families. The mean of plasma enzyme activity was higher for males than females, higher in winter months, lower in summer months and decreased with increased age. Estimates of carrier probabilities indicate that the test is most effective when animals are sampled as calves, although effectiveness of the plasma assay was less for males than females. Test effectiveness was enhanced through averaging repeated assays of enzyme activity on each animal. Our approach contributes to medical diagnostics in several ways. Rather than assume underlying normality for the distributions comprising the mixture, we estimate transformations to normality for each genotype distribution simultaneously with all other model parameters. This process also excludes potential biases due to data preadjustment for systematic effects. We also provide a method for partitioning phenotypic variation within each genotypic distribution which allows an assessment of the value of repeat measurements of the predictive variable for genotype assignment.
Subject(s)
Cattle Diseases/genetics , alpha-Mannosidosis/veterinary , Animals , Cattle , Cattle Diseases/enzymology , Female , Gene Frequency , Genotype , Humans , Male , Mannosidases/blood , Mannosidases/deficiency , Mannosidases/genetics , Models, Genetic , Models, Statistical , Probability , Seasons , United States , alpha-Mannosidosis/enzymology , alpha-Mannosidosis/genetics , beta-MannosidaseABSTRACT
This study reports the percentage of cattle farms with ivermectin (IVM) resistant gastrointestinal nematodes (GINs) in Veracruz, Mexico, and identifies the GIN genera involved in the resistances. It also describes management practices of anthelmintic (AH) use on the surveyed farms. Twenty-one farms were assessed by means of the faecal egg count reduction test using the McMaster technique. Only two farms had GIN populations susceptible to IVM (9.5%). The proportion of farms with IVM resistant GIN was 71.4% (15/21). Seven of these farms had less than 80% egg count reductions. Haemonchus and Cooperia were the genera most commonly found in the resistant populations, followed by Oesophagostomum. Inappropriate AH treatment practices were identified from the completed questionnaires. Further management practices such as selective treatment and quarantine treatments are proposed to further reduce the spread of IVM resistance between farms.
Subject(s)
Cattle Diseases/parasitology , Drug Resistance , Gastrointestinal Diseases/veterinary , Ivermectin/pharmacology , Nematoda/drug effects , Nematode Infections/veterinary , Animals , Anthelmintics/pharmacology , Cattle , Cattle Diseases/epidemiology , Data Collection , Gastrointestinal Diseases/epidemiology , Gastrointestinal Diseases/parasitology , Mexico/epidemiology , Nematode Infections/epidemiology , Nematode Infections/parasitology , Surveys and QuestionnairesABSTRACT
The purpose of this study was to investigate the effects of cohort size on maximum likelihood estimates of mortality parameters. Recent experimental investigations have stressed the importance of large cohorts for detecting leveling off of mortality rates at older ages. In the present study, emphasis was placed on evaluation of relatively small cohorts (about 150-300 individuals). Deaths were simulated under the assumption of the frailty mortality model. Two different parameter sets that resulted in differences in mean life span of more than twofold were used for simulations. Our smallest cohorts yielded parameter estimates that had generally good statistical properties, but relatively large standard errors. For tests of hypotheses concerning equality of parameters among populations or experimental treatments, empirical standard errors (obtained from several cohorts) were preferable to asymptotic standard errors (obtained for single cohorts). In particular, empirical standard errors yielded reliable type I error rates.
Subject(s)
Cohort Studies , Likelihood Functions , Longevity , Models, Theoretical , Mortality , Computer Simulation , HumansABSTRACT
OBJECTIVE: Decreases in circulating growth hormone (GH) and its main biological messenger insulin-like growth factor-I (IGF-I) have been interpreted as part of the aging process. Because estrogens participate in modulating GH synthesis and secretion, hypoestrogenism in menopausal women may lead to GH deficiency. The aim of the present study was to determine the effect of hormone replacement therapy (HRT) on both GH and IGF-I levels as well as insulin concentrations in 50 menopausal women. DESIGN: Patients were assigned randomly into two treatment groups of 25 each; one group received three cycles of conjugated equine estrogen (CEE) 0.625 mg/day for 21 days, and the other, 1.25 mg/day during 21 days. Each also received chlormadinone acetate for 5 days. There was a control group consisting of regularly menstruating women. RESULTS: In the menopausal women, HRT increased significantly (p < 0.001) the low levels of GH and IGF-I; on the contrary the baseline insulin levels declined (p < 0.001) with HRT. A significant linear correlation (r = 0.90) was found between GH and IGF-I as well as with estradiol levels (r = 0.74) in the group of menopausal women receiving CEE 0.625 mg/day. This group of patients had a significant correlation (r = -0.63) between insulin and estradiol levels. No correlation was observed in the group receiving CEE 1.25 mg/day. CONCLUSIONS: HRT restored GH, IGF-I, and insulin levels to normal values in all women. Further research needs to be done to establish the beneficial effect of HRT regarding the prevention of the metabolic effects presumably caused by derangement in the somatotropic axis associated with aging.
Subject(s)
Hormone Replacement Therapy , Human Growth Hormone/blood , Insulin-Like Growth Factor I/analysis , Insulin/blood , Postmenopause/drug effects , Aged , Aging/physiology , Analysis of Variance , Chlormadinone Acetate/therapeutic use , Contraceptives, Oral, Synthetic/therapeutic use , Dose-Response Relationship, Drug , Drug Administration Schedule , Estrogens, Conjugated (USP)/therapeutic use , Female , Human Growth Hormone/drug effects , Humans , Insulin/metabolism , Insulin Secretion , Insulin-Like Growth Factor I/drug effects , Linear Models , Middle Aged , Postmenopause/physiologyABSTRACT
OBJECTIVE: To investigate the relationship of creatine phosphokinase and its isoenzymes with fetal asphyxia and risk at birth. METHODS: Thirty-five pregnant women with high-risk pregnancy were studied. RESULTS: In 21 patients, fetal distress was diagnosed by interpretation of the fetal heart rate tracing (FHR). The remaining 14 women, having normal fetal cardiotocography, were considered as the control group. Total CK and its isoenzymes activity was measured in cord sera and 24 h after birth in peripheral blood. Abnormal FHR patterns correlate well with elevated enzyme activities. Total CK and its isoenzymes (CK-MM, CK-MB, and CK-BB) exhibited higher values in asphyxiated infants as compared to normal neonates. Electrocardiographic ischemia occurred in seven newborns who had elevated CK-MB and CK-BB levels, both at birth and within 24 h postpartum. Chromatographic study showed in normal neonates that the predominant isoenzyme was CK-MM, whereas CK-BB activity was negligible. In the newborns with abnormal FHR, CK-MB and CK-BB were increased with predominance of CK-MB. CONCLUSIONS: Antepartum fetal distress is associated with release of CK-BB, and particularly CK-MB; therefore, these biochemical markers may indicate either brain or myocardial damage.
Subject(s)
Asphyxia Neonatorum/enzymology , Creatine Kinase/blood , Infant, Newborn/blood , Isoenzymes/blood , Creatine Kinase/chemistry , Creatine Kinase/physiology , Delivery, Obstetric , Female , Heart Rate, Fetal , Humans , Isoenzymes/chemistry , Isoenzymes/physiology , Pregnancy , Risk Factors , Time FactorsABSTRACT
OBJECTIVE: To demonstrate if GH concentrations and molecular heterogeneity of GH correlates with the presence of galactorrhea in normoprolactinemic women with normal ovarian function. DESIGN: Aliquots of sera from women with normal ovarian function and normoprolactinemic galactorrhea were subjected to gel filtration chromatography, and the fractions were assayed for GH by the use of radioimmunoassay. Molecular weight of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, molecular weight (MW), and partition coefficient. RESULTS: Basal serum GH levels were moderately elevated in all six normoprolactinemic women exhibiting galactorrhea. Chromatographic study of sera from these normoprolactinemic women showed the predominance of 40 to 50 kd molecular forms of GH as well as some very low MW GH isoforms. This pattern was different from that obtained in sera from normal women without galactorrhea who presented a predominance of heavier (> 60 kd) isoforms eluted before the GH labeled standard. The monomeric forms were present in less proportion but there was no significant difference as compared with galactorrheic group. CONCLUSIONS: Our investigation demonstrated elevated GH basal serum levels is normoprolactinemic women with galactorrhea, and chromatography in gel showed a low proportion of the large MW GH variants associated with a higher proportion of the dimeric forms and very low MW forms of GH. This is different from normal women without galactorrhea who had a predominance of heavier MW GH variants and lesser proportion of < 16 kd isoforms. It is concluded that an increased GH secretion may be responsible for abnormal lactation despite normal PRL levels in some women with normal ovarian function.
Subject(s)
Galactorrhea/blood , Growth Hormone/blood , Ovary/physiology , Prolactin/blood , Adult , Chromatography, Gel , Female , Humans , Isomerism , Radioimmunoassay , Reference ValuesABSTRACT
OBJECTIVE: We determined gastrin concentrations in newborns and their mothers both before and during lactation. METHODS: Twenty-five women who had uncomplicated pregnancies with normal vaginal delivery of healthy infants at term participated in the study. Twelve preterm neonates with low birth weight (LBW) were also studied. Gastrin levels were determined by radioimmunoassay in amniotic fluid and in serum of both the neonates and their mothers at birth and during breast-feeding. Serum levels of gastrin and prolactin (PRL) were measured in the mothers before and after tactile self-stimulation of the breast. RESULTS: In normal newborns, gastrin levels in cord sera were significantly higher than levels in maternal blood and amniotic fluid at birth. However, gastrin cord sera in LBW newborns was lower than in the normal neonates. Nursing resulted in an increment of serum gastrin levels in the infants and mothers; this rise was similar in the 3 postpartum weeks tested. Tactile stimulus of the mother's nipple resulted in increases of both gastrin and PRL. CONCLUSIONS: Newborns at term show significantly higher gastrin levels than do LBW neonates, which may indicate differences in development of the gastrointestinal system. Breast-feeding induced gastrin secretion in both mothers and infants, confirming the presence of an active vagal reflex. In addition, tactile stimulation of the nipple increased gastrin and PRL levels in the mothers. Our data suggest that LBW neonates have deficient production of gastrin, which in turn may indicate an undeveloped gastrointestinal system. An early enteral feeding triggers the postnatal increase in concentrations of gut hormones.