Post-COVID-19 Lung Transplantation Italian Pivotal Protocol: Some Ethical Considerations.

SARS­CoV­2 mostly affects the respiratory system with clinical patterns ranging from the common cold to fatal pneumonia. During the first wave of the COVID-19 pandemic, owing to the high number of patients who were infected with SARS­CoV­2 and subsequently recovered, it has been shown that some patients with post-COVID-19 terminal respiratory failure need lung transplantation for survival. There is increasing evidence coming from worldwide observations that this procedure can be performed successfully in post-COVID-19 patients. However, owing to the scarcity of organs, there is a need to define the safety and efficacy of lung transplant for post-COVID-19 patients as compared to patients waiting for a lung transplant for other pre-existing conditions, in order to ensure that sound ethical criteria are applied in organ allocation. The Milan's Policlinic Lung Transplant Surgery Unit, with the revision of the National Second Opinion for Infectious Diseases and the contribution of the Italian Lung Transplant Centres and the Italian National Transplant Centre, set up a pivotal observational protocol for the lung transplant of patients infected and successively turned negative for SARS­CoV­2, albeit with lung consequences such as acute respiratory distress syndrome or some chronic interstitial lung disease. The protocol was revised and approved by the Italian National Institute of Health Ethics Committee. Description of the protocol and some ethical considerations are reported in this article.

Incidental pancreatic cystic lesions: comparison between CT with model-based algorithm and MRI.

INTRODUCTION: The present study aims to compare low-kV CT reconstructed with MBIR technique with MRI in detecting high-risk stigmata and worrisome features in patients with pancreatic cystic lesions. METHODS: We retrospective enrolled 75 patients who underwent low-kV CT with contrast media injection for general abdominal disorders and MRI with MRCP sequences. The reviewer, blinded to clinical and histopathological data, recorded the overall number of pancreatic cystic lesions, size, location, presence of calcifications, septa, or solid enhancing or non-enhancing components, main pancreatic duct (MPD) communication, and MPD dilatation. Mean differences with 95% limits of agreement, ICC, and κ statistics were used to compare CT and MRI. RESULTS: More pancreatic cystic lesions were detected with MRI than with CT, however, the ICC value of 0.81 suggested a good agreement. According to the evaluated target lesion, a very good agreement (ICC = 0.98) was found regarding the diameter (21.4 mm CT vs 21.8 mm MRI), the location (κ = 0.90), the detection of MPD dilatation (κ = 1), the presence of septa (κ = 0.86) and the MPD communication (κ = 0.87). A moderate agreement on the assessment of enhanced components was noted (κ = 0.44), while there was only a fair agreement about the presence of calcifications (κ = 0.87). CONCLUSION: MDCT can be considered almost equivalent to MRI with MRCP in the evaluation of worrisome features and high-risk stigmata, offering detailed morphologic features helpful for their characterization. IMPLICATIONS FOR PRACTICE: Even if MRI is considered the reference standard in pancreatic cystic lesions characterization, CT can be considered a useful tool as a first-line imaging technique to identify worrisome features and high-risk stigmata.

Is there a benefit of frequent CT follow-up after EVAR?

OBJECTIVE: Imaging follow-up (FU) after endovascular aneurysm repair (EVAR) is usually performed by periodic contrast-enhanced computed tomography (CT) scans. This study aims to evaluate the effectiveness of CT-FU after EVAR. METHODS: In this study, 279 of 304 consecutive patients (261 male, aged 74 years (interquartile range (IQR): 70-79 years) with a median abdominal aortic aneurysm (AAA) diameter of 58 mm (IQR: 53-67 mm)) underwent at least one of the yearly CT scans and plain abdominal films after EVAR. All patients received Zenith stent-grafts for non-ruptured AAAs at a single institution. Patients were considered asymptomatic when a re-intervention was done solely due to an imaging FU finding. The data were prospectively entered in a computer database and retrospectively analysed. RESULTS: As a follow-up, 1167 CT scans were performed at a median of 54 months (IQR: 34-74 months) after EVAR. Twenty-seven patients exhibited postoperative AAA expansion (a 5-year expansion-free rate of 88+/-2%), and 57 patients underwent 78 postoperative re-interventions with a 5-year secondary success rate of 91+/-2%. Of the 279 patients, 26 (9.3%) undergoing imaging FU benefitted from the yearly CT scans, since they had re-interventions based on asymptomatic imaging findings: AAA diameter expansion with or without endoleaks (n=18), kink in the stent-graft limbs (n=4), endoleak type III due to stent-graft limb separation without simultaneous AAA expansion (n=2), isolated common iliac artery expansion (n=1) and superior mesenteric artery malperfusion due to partial coverage by the stent-graft fabric (n=1). CONCLUSIONS: Less than 10% of the patients benefit from the yearly CT-FU after EVAR. Only one re-intervention due to partial coverage of a branch by the stent-graft would have been delayed if routine FU had been based on simple diameter measurements and plain abdominal radiograph. This suggests that less-frequent CT is sufficient in the majority of patients, which may simplify the FU protocol, reduce radiation exposure and the total costs of EVAR. Contrast-enhanced CT scans continue, nevertheless, to be critical when re-interventions are planned.

From Experimental Technique to Clinical Practice: Which Pathway in Transplant Surgery?

The question of whether a medical procedure is to be considered experimental or routine practice has enormous practical implications. In transplant surgery, as compared with pharmacologic clinical trials, the transition from experimental procedure to normal care is far from clear cut. Clinical trials comprise 4 well-established phases of evaluation going from phase I, aimed at assessing safety and identifying side effects in a few healthy volunteers, to phase IV, which involves entire populations and is aimed at long-term postmarketing surveillance. In transplant surgery, technical progress and experimentation follow more atypical and individual routes. As compared with pharmacologic research, the decision about "routine practice readiness" of a surgical procedure does not rely on a standardized formal act but rather on experts' capacity to find a consensus based on best practices and on ad-hoc criteria as well. Independent assessment by a panel of experts and oversight by an institutional review board are key to facilitating meaningful protection of transplant recipients and allowing the research to go forward. The framework of the human subjects protection regulations should also consider the transplant of organs that have previously been part of a research project.

Kissing stents in the aortic bifurcation--a valid reconstruction for aorto-iliac occlusive disease.

OBJECTIVE: To evaluate outcome and patency predicting factors of kissingstent treatment for aorto iliac occlusive disease (AIOD). METHODS: Patients treated with kissingstents for AOID between 1995 and 2004 at a tertiary referral center were identified through local databases. Chart review and preoperative images were used for TASC and Fontaine classification. Follow-up consisted of clinical exams, ABI and/or duplex. Patency rates were estimated by Kaplan-Meier analysis, and Cox multivariate regression was used to determine factors associated with patency. RESULTS: 173 consecutive patients (46% male, mean 64 years) were identified. TASC distribution was: A 15%, B 34%, C 10%, D 41%. Mean follow-up was 36 months (range: 1-144). 30-day mortality was 1% (2 patients), and 1-year survival was 91% (157 patients). 2 patients underwent late, open conversion and 13 patients suffered minor puncture site complications. Primary, assisted primary and secondary patency was: 97%, 99% and 100%, and 83%, 90% and 95% at twelve and 36 months respectively. There was no significant difference in patency between the TASC groups. Patency was significantly worse for patients in Fontaine class III. CONCLUSIONS: Aortoiliac kissing stents is a valid alternative to open repair for TASC A-D lesions. The procedure has low mortality and morbidity and good patency at 3 years.

PML-RARA-associated cooperating mutations belong to a transcriptional network that is deregulated in myeloid leukemias.

It has been shown that individual acute myeloid leukemia (AML) patients are characterized by one of few initiating DNA mutations and 5-10 cooperating mutations not yet defined among hundreds identified by massive sequencing of AML genomes. We report an in vivo insertional-mutagenesis screen for genes cooperating with one AML initiating mutations (PML-RARA, oncogene of acute promyelocytic leukemia, APL), which allowed identification of hundreds of genetic cooperators. The cooperators are mutated at low frequency in APL or AML patients but are always abnormally expressed in a cohort of 182 APLs and AMLs analyzed. These deregulations appear non-randomly distributed and present in all samples, regardless of their associated genomic mutations. Reverse-engineering approaches showed that these cooperators belong to a single transcriptional gene network, enriched in genes mutated in AMLs, where perturbation of single genes modifies expression of others. Their gene-ontology analysis showed enrichment of genes directly involved in cell proliferation control. Therefore, the pool of PML-RARA cooperating mutations appears large and heterogeneous, but functionally equivalent and deregulated in the majority of APLs and AMLs. Our data suggest that the high heterogeneity of DNA mutations in APLs and AMLs can be reduced to patterns of gene expression deregulation of a single 'mutated' gene network.

High resolution scanning electron microscopy of the intracellular surface of intercalated disks in human heart.

The three-dimensional architecture of human cardiac intercalated disks was examined by high resolution scanning electron microscopy of osmium-macerated specimens. This methodology permits viewing of in situ intercalated disks from a vantage point inside individual cardiomyocytes. The erose nature of these structures was rendered in stark relief. Areas covered with clusters of particles were present on some membranous projections--these may represent a combination of desmosomes and fasciae adherentes. On the other hand, areas devoid of particles may correspond to gap junctions.

Lipomatous hypertrophy of the interatrial septum. Description of a clinical case and literature review.

UNLABELLED: Lipomatous hypertrophy of the interatrial septum is a rare benign cardiac disorder characterised by the accumulation of adipose tissue; data from several post mortem surveys report how the disorder represents 0.6% of all benign cardiac tumours. Generally asymptomatic, it frequently constitutes an incidental post mortem finding. The disorder may at times lead to a pumping deficit associated to congestive heart failure or determine an abnormal heart rhythm leading even to sudden death. Lipomatous hypertrophy can at times lead to problems in differential diagnosis of the disorder from other tumours or heart diseases. Surgical removal produces excellent short and long-term RESULTS: We describe a case of lipomatous hypertrophy of the interatrial septum associated to coronary disease diagnosed by means of transesophageal echocardiography. The diagnostic and treatment techniques applied are discussed and a literature review is done.

Pharmacokinetics and cerebrospinal fluid penetration of CI-994 (N-acetyldinaline) in the nonhuman primate.

CI-994 is a substituted benzamide derivative that has demonstrated significant antitumor activity in vitro and in vivo against a broad spectrum of murine and human tumor models. Its mechanism of action is still unknown but seems to be novel compared with existing anticancer drugs. We studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics of CI-994 in nonhuman primates. Three animals (total 4 doses) received an 80 mg/m2 dose of CI-994 administered over 20 min, and one animal received a dose of 100 mg/m2. Serial plasma and fourth ventricular CSF samples were obtained from 0 to 4320 min after administration of the 80-mg/m2 dose, and only plasma samples were obtained after the 100-mg/m2 dose. CI-994 was measured using a previously validated reverse-phase high-performance liquid chromatography assay. Elimination of CI-994 from plasma was triexponential (4 of 5 cases) or biexponential (1 of 5 cases), with a terminal half life (t1/2) of 7.4 +/- 2.5 h, volume of distribution of 15.5 +/- 1.8 L/m2, and clearance of 40 +/- 6 ml/min/m2. The area under the concentration-time curve (AUC) for the 80-mg/m2 dose was 125 +/- 17 microM x hr. CI-994 was first detected in CSF at the completion of the i.v. infusion. Peak concentrations of CI-994 in CSF were 3.4 +/- 0.3 microM. Elimination from CSF was monoexponential (2 of 4 cases) or biexponential (2 of 4 cases) with a terminal t1/2 in CSF of 12.9 +/- 2.5 h and AUC of 55 +/- 18 microM x hr. The AUC(CSF):AUCplasma ratio was 43 +/- 10%. This study demonstrates that there is excellent CSF penetration of CI-994 after i.v. administration. Additional studies are needed to evaluate the potential role of CI-994 in the treatment of central nervous system neoplasms.

Characterization of the angiotensin II AT1 receptor subtype involved in DNA synthesis in cultured vascular smooth muscle cells.

1. This study was undertaken in cultured vascular smooth muscle cells to characterize the angiotensin II (AII) AT1 receptor subtype involved in DNA synthesis because (i) the AII receptor involved in vascular proliferation has previously been characterized in vitro in rat aortic cells and identified as an AT1 subtype and (ii) molecular cloning and biochemical studies have provided evidence for the existence of different AT1 receptor subtypes. 2. In cultured rat aortic vascular smooth muscle (VSMC), exposure to AII (0.1 to 100 nM) resulted in a concentration-dependent increase in [3H]-thymidine incorporation with an EC50 of 1.41 +/- 0.51 nM. Maximal stimulation was observed in the presence of 100 nM AII and corresponded to 271 +/- 40% of basal [3H]-thymidine incorporation. 3. To characterize the AII AT1 receptor subtype involved in this effect, cells were exposed to AII (3 nM) in the absence or presence of increasing concentrations of various AII receptor antagonists. The stimulatory effect of AII (3 nM) on [3H]-thymidine incorporation in VSMC was antagonized by the non-selective AT1/AT2 receptor antagonist, [Sar1, Ile8]-AII (IC50 = 5.6 nM), by the AT1A/AT1B receptor antagonist, losartan (IC50 = 10.5 nM) and the AT1 receptor antagonist, L-158809 (IC50 = 0.20 nM). The selective AT2 receptor ligand, CGP 42112A, antagonized AII-induced [3H]-thymidine incorporation with an IC50 of 6.3 +/- 1.3 microM while the AT2/AT1B receptor antagonist, PD 123319, was found to be almost inactive (IC50 > 10 microM). 4. Under the same experimental conditions, angiotensin III (AIII) was found to be at least 50 times less potent than All with an apparent EC50 of 81.6 +/- 7.7 nM. At the highest concentration tested (10 microM),the effect of AIII corresponded to 327 +/- 61% of basal [3H]-thymidine incorporation.5. These results confirm that All can stimulate DNA synthesis in VSMC through an AT, receptor.Furthermore, the pharmacological characterization of this AT1 receptor is compatible with the ATlA receptor subtype recently described on cultured mesangial cells since (i) the ATIA/ATIB receptor antagonist losartan is active at nanomolar concentrations, (ii) micromolar concentrations of the AT2/AT1B receptor antagonist PD 123319 are ineffective at antagonizing the AII-induced [3H]-thymidine incorporation and (iii) All is at least 50 times more potent than AIII in stimulating DNA synthesis.

A study of early ongoing activity in dorsal horn units following sciatic nerve constriction.

An analysis was made of the background activity of spinal neurones involved in nociceptive processes during, and in the first hour after, sciatic nerve constriction in normal rats and in rats in which sciatic nerve conduction had been previously blocked with local anaesthetic. In both pure noxious and WDR neurones the results showed high frequency discharges at the time of ligation, followed by a slight but persistent increase in activity that reached, after 1 h, values 6-8 times those preligature. The increased post-injury discharge could be reduced by secondarily applying lidocaine on the peripheral site of constriction. There were no neuronal activity changes after the ligatures in rats with sciatic nerve pretreated with local anaesthetic. The likelihood that the early persistent increase in activity may have a role in the excitability change of spinal neurones observed in neuropathic pain is discussed.

Poststimulus afterdischarges of spinal WDR and NS units in rats with chronic nerve constriction.

Forty pairs of wide dynamic range (WDR) and nociceptive specific (NS) neurones were simultaneously recorded in the dorsal horn of rats with chronic constriction injury (CCI) of the sciatic nerve. The responses to noxious mechanical stimulation were analysed and the afterdischarges were compared in the two neuronal populations. The number of neurones presenting an afterdischarge was higher in WDR than in NS population. Furthermore afterdischarges had significantly longer duration and greater magnitude with slower time course decays in WDR than in NS neurones. Given the role that afterdischarge may have in the prolonged transmission of nociceptive information, the possibility that WDR neurones could give a major contribute to the abnormal processing of noxious signals in CCI rats is proposed.

Pharmacological characterization of a specific binding site for angiotensin IV in cultured porcine aortic endothelial cells.

This study demonstrated the existence of a specific binding site for angiotensin IV in porcine aortic endothelial cells. Non-equilibrium kinetic analyses at 37 degrees C allowed the calculation of a kinetic Kd of 0.44 nM. Pseudo-equilibrium saturation binding studies at 37 degrees C for 90 min indicated the presence of a single high-affinity site (Kd = 3.87 +/- 0.60 nM), saturable and abundant (Bmax = 9.64 +/- 1.44 pmol/mg protein). Competitive binding studies demonstrated the following rank order of effectiveness: angiotensin IV > angiotensin III > angiotensin II > angiotensin I > angiotensin II-(1-7), while 2-n-butyl-4-chloro-5-hydroxymethyl-1 [(2'-(1H-tetrazol-5-yl) biphenyl-4-yl) methyl] imidazol (DuP 753: losartan), 1-(4-amino-3-methyl-phenyl) methyl-5-diphenylisoethyl-4,5,6,7-tetrahydro-1H-imidazo [4,5-C] pyridine-6-carboxylic acid (PD 123177) or nicotinic acid-Tyr-(N alpha -benzyl-oxycarbonyl-Arg) Lys-His-Pro-Ile-OH (CGP 42112A) were inactive at the concentration of 100 microM. This binding site is, therefore, distinct from angiotensin II receptors, AT1 and AT2. Addition of the divalent cations Mg2+, Mn2+ or Ca2+ to the incubation buffer resulted in 90-95% inhibition of the [125I]angiotensin IV-specific binding to porcine aortic endothelial cells. Furthermore, the chelator, EGTA, at 5 mM increased the number of binding sites (Bmax = 17.8 +/- 2.5 pmol/mg protein), with no change in affinity (Kd = 5.7 +/- 1.3 nM). Exposure of porcine aortic endothelial cell membranes to the non-hydrolyzable GTP analog, GTP gamma S, had no effect on [125I]angiotensin IV binding. The presence of a high concentration of binding sites for angiotensin IV in porcine aortic endothelial cells suggests that this peptide may play an important role in the modulation of the cardiovascular system.

Effect of liposome-encapsulated alpha- or beta-interferon on breast cancer cell lines.

Experimental evidence and clinical studies have indicated that interferons (IFN) inhibit proliferation in a wide panel of neoplasms, including breast cancer. However, the antitumor activity of IFN requires the continuous presence of high concentrations of the drug and is associated with side effects. To explore the potential of liposomes as an IFN delivery system, we compared the effect of free or liposome-encapsulated alpha-IFN and beta-IFN on the growth of two breast cancer cell lines (MCF7 and MDA-MB231). Cells were cultured in the presence of IFN at different concentrations (500, 1000, 2000 IU/ml) or in the presence of multilamellar liposomes (phosphatidylcholine-phosphatidylserine at a molar ratio of 7:3) containing saline buffer, alpha-IFN or beta-IFN. Additional control groups consisted of cells cultured with alpha-IFN or beta-IFN plus empty liposomes. Empty liposomes were not cytotoxic and did not interfere with IFN activity. In both cell lines liposomes encapsulating alpha-IFN (at the highest lipid:drug ratio) inhibited cell growth in a manner similar to that of free alpha-IFN, whereas liposomes encapsulating beta-IFN showed slightly, lower inhibition than free beta-IFN, this was more evident in MCF7 cells. The present results indicate that liposomes encapsulating alpha-IFN or beta-IFN were effective on the growth of both breast cancer cell lines, which are characterized by a different estrogen responsiveness, and that they might be a useful carrier system for the delivery of high doses of IFN.

Cell cycle-related phosphatases CDC25A and B expression correlates with survival in ovarian cancer patients.

Alterations in cell cycle regulating proteins are common in many cancer types. Recent data suggest a possible link between CDC25 phosphatases overexpression and malignancy. Our objective was to evaluate the expression of the three cell cycle-related phosphatases CDC25A, CDC25B and CDC25C in patients with ovarian cancer. All the patients had a minimal follow up of three years. CDC25A, CDC25B and CDC25C expression were investigated by immunohistochemistry in 106 patients with ovarian cancer. CDC25A and CDC25B were found expressed in almost all the samples analyzed, while CDC25C was undetectable in more than 80% of the patients. The low evaluable data on CDC25C expression, did not allow any association between the expression of this phosphatase and prognosis. The expression of CDC25A and CDC25B showed some evidences of association with a poor prognosis (p = 0.034 and p = 0.058 respectively). This relationship was independent of other factors such as tumor grade, histotype, stage and residual tumor after surgery. In the same patients the examined parameters (residual tumor, grade, stage and histotype) did show the expected relation with survival. The results indicate that high CDC25A and CDC25B expression is related to a worse prognosis in ovarian cancer patients. CDC25 phosphatases expression can be regarded as a possible prognostic factor for ovarian cancer and these proteins should be evaluated as potential molecular targets of novel drugs against this human neoplasm.

The antiproliferative effects of Uncaria tomentosa extracts and fractions on the growth of breast cancer cell line.

Uncaria tomentosa, also known as "Uña de gato", is a Rubiaceae species widely used in South-American folk medicine for the treatment of cancer, arthritis, gastritis and epidemic diseases. Extracts of the plant have been shown to possess cytostatic and anti-inflammatory activity as well as mutagenic and antimutagenic properties. However, to date no studies have been carried out to verify the direct antitumor activity of the extracts. The present study investigates the effects of some extracts and their chromatographic fractions from the bark of U. tomentosa on the growth of a human breast cancer cell line (MCF7). Our data indicated that, in addition to the antimutagenic activity, U. tomentosa extracts and fractions exert a direct antiproliferative activity on MCF7. The bioassay-directed fractionation from barks and leaves resulted in the isolation of two active fractions, which displayed an IC50 of 10 mg/ml and 20 mg/ml, respectively and an antiproliferative effect, with about 90% of inhibition at a concentration of 100 mg/ml.

Efficacy and tolerability of moclobemide in bulimia nervosa: a placebo-controlled trial.

A 6-week double-blind placebo-controlled trial was carried out to examine the efficacy and tolerability of moclobemide, a monoamine oxidase type A selective and reversible inhibitor, in the treatment of bulimia nervosa. Patients were admitted to the study even if they were unable to adhere to a tyramine-free diet. Fifty-two normal-weight women (age range 18-40 years) suffering from bulimia nervosa (DSM-IV criteria) completed the trial. Particular emphasis was placed on evaluating the incidence of hypertension and other side-effects in chronically treated patients. At the usual antidepressant dose of 600 mg, moclobemide was not significantly superior to placebo in the reducing the weekly number of binge eating episodes or in improving several measures of eating attitudes and behaviour (BITE, EDI, TFEQ) in normal-weight bulimia nervosa. The dropout rate was relatively low (29%), and the side-effects were limited and equally distributed between the two treatment groups. No patient experienced a hypertensive crisis during the study and no serious side-effect was detected. The study indicates that moclobemide 600 mg pro die is not efficacious in bulimia nervosa, but it can be safely administered, even to young subjects, at a very high risk of consuming large amounts of tyramine-rich foods without dietary restrictions.

[Action of trazodone on the secretion of pituitary hormones. Behavior of prolactin and somatotropin]. / Studio dell'azione del trazodone sulla secrezione di ormoni ipofisari. Comportamento della prolattina e del somatotropo.

The effect of i.v. trazpdone on PRL and GH was studied in normal subjects and in patients with hypophyseal adenoma coupled with amenorrhoea and galactorrhoea or acromegaly. PRL levels were reduced, whereas the behaviour of GH was paradoxical. These results suggest that the dopaminergic and serotoninergic systems take part in regulating the secretion of these two hormones. An interesting comparison was made with their behaviour following the administration of bromoergocryptine in the adenoma series.

[An information survey on the automatic operation of intensive therapy units in Italy]. / Indagine conoscitiva sulla gestione automatica delle sale di terapia intensiva in Italia.

A fact finding study was carried out in 58 resuscitation centres and 78 intensive care units to evaluate the current application of computerised techniques in the monitoring and processing of various parameters relating to hospitalised patients. The enquiry revealed a marked interest in the use of computerised systems, particularly in the electrophysiological and haemodynamic field. Promising results were reported from some centres. Some adverse criticisms and points of discussion still exist. International and national experiences matured so far, however, while primarily directed towards scientific research and technological development, open up significant perspectives for the future, for the rational handling of the data collected, and the extension of current knowledge on matters of physiopathology, electrophysiology, and pharmacokinetics.

Weight growth in infants born to mothers who smoked during pregnancy.

OBJECTIVE: To determine whether maternal smoking during pregnancy causes impairment in growth after birth. DESIGN: Longitudinal study. SETTING: Six medical university centres of six towns of north, central, and south Italy. SUBJECTS: 12,987 babies (10,238 born from non-smoking mothers, 2276 from mothers smoking one to nine cigarettes a day, and 473 from mothers smoking > or = 10 cigarettes a day) entered the study. MAIN OUTCOME MEASURES: Difference in weight gain between children born to smoking mothers and those born to non-smoking mothers. Weight was measured at birth and at 3 and 6 months of age. Maternal smoking habit was derived from interview on third or fourth day after delivery. RESULTS: Compared with children born to mothers who did not smoke during pregnancy, the birth weights of children born to mothers who smoked up to nine cigarettes a day were 88 g (girls) and 107 g (boys) lower; in children born to mothers who smoked > or = 10 cigarettes a day weights were 168 g and 247 g lower. At six months of age for the first group the mean weight for girls was 9 g (95% confidence interval -47 g to 65 g) higher and for boys 64 g (-118 g to -10 g) lower than that of children born to mothers who did not smoke. The corresponding figures for the second group were 28 g (-141 g to 85 g) lower for girls and 24 g (-136 g to 88 g) lower for boys. CONCLUSIONS: The deficits of weight at birth in children born to mothers who smoked during pregnancy are overcome by 6 months of age. These deficits are probably not permanent when smoking habit during pregnancy is not associated with other unfavourable variables (such as lower socioeconomic class).