Microcontroller-driven fluid-injection system for atomic force microscopy.

We present a programmable microcontroller-driven injection system for the exchange of imaging medium during atomic force microscopy. Using this low-noise system, high-resolution imaging can be performed during this process of injection without disturbance. This latter circumstance was exemplified by the online imaging of conformational changes in DNA molecules during the injection of anticancer drug into the fluid chamber.

Scleredema adultorum of Buschke: an under recognized skin complication of diabetes.

Scleredema of Buschke or scleredema diabetorum is a skin complication of diabetes with deposits of collagen and aminoglycans in the dermis. This disease characterized by thickening and hardening of the skin, is usually localized in nape, back and shoulder areas. Consequences could be a decrease in motility of the shoulders and an impairment of respiratory function. Other possible complications are sleep apnoea syndrome and monoclonal gammapathy. Type 1 or type 2 diabetes may be associated with scleredema of Buschke in more than 50% of cases. Diabetes-related risk factors are long duration of the disease, presence of microangiopathy, overweight and need of insulin. Various specific treatments proposed in the literature are poorly validated. In most severe cases, radiation therapy may be useful.

Melatonin has dose-dependent effects on folliculogenesis, oocyte maturation capacity and steroidogenesis.

Chemo and/or radiotherapy applied to young cancer patients most often have severe effects upon female fertility. Today, few options are available to protect ovarian function in females. However, these options are either ineffective, belong to the field of experimental research or/and are not applicable to all patients. Drugs that could protect the oocyte and its surrounding feeder cells from damage can be of great importance. Melatonin, being an important indirect antioxidant and a powerful direct free radical scavenger could be such a reagent. This paper reports the direct effects of different melatonin concentrations (range: 1 nM to 2 mM) on folliculogenesis and oogenesis of in vitro cultured mouse ovarian follicles. Early secondary mouse follicles were cultured in vitro for 12 days under different melatonin regimes. Every fourth day, survival rates were scored, follicles were morphologically evaluated and medium was collected for steroid analyses. On day 12, in vitro ovulation was induced by hCG/EGF. Eighteen hours later, oocytes were measured, oocyte maturation was evaluated and normality of spindle and chromosomes ascertained. Results obtained in this study indicated that 2mM melatonin is toxic. One mM negatively influenced oocyte maturation capacity. In the presence of 100 microM melatonin, androstenedione and progesterone were increased whereas estradiol was not influenced. Lower melatonin concentrations had no effect on the evaluated parameters. These data indicate an effect of melatonin on theca cell steroidogenesis. For prophylactic use, a dose of 10 microM could be suitable to reduce oxidative stress in cultured follicles.

Sensitivity of germ cells and embryos to ionizing radiation.

Experiments performed in laboratory animals suggest that ionizing radiation can induce DNA damage in the germ cells of exposed individuals and lead to various deleterious effects in their progeny, including miscarriage, low birth weight, congenital abnormalities and perhaps cancer. However, no clear evidence for such effects has been found in epidemiological studies of people exposed to radiation. The predicted risks of hereditary effects of any kinds resulting from parental exposure to relatively low doses of ionizing radiation remain very low, compared to the spontaneous risks in the absence of irradiation. Irradiation of the mouse embryo can lead to various effects (lethality, growth retardation, congenital abnormalities), depending on the period of gestation at which irradiation occurs. In humans, prenatal irradiation has only been exceptionally associated with congenital abnormalities, but irradiation between weeks 8-25 has been shown to be able to induce severe mental retardation. Although being not proven, the risk of developing a childhood cancer following prenatal irradiation may also not be excluded. Like for genetic effects, the risk of adverse effects following exposure of the embryo to relatively low doses remains quite low compared to the natural risks.

Effect of curcuma on radiation-induced apoptosis in human cancer cells.

There have been considerable efforts to search for naturally occurring substances for the intervention of carcinogenesis. Many components from dietary or medicinal plants have been identified that possess substantial chemopreventive properties. Curcuma, a yellow pigment from Curcuma longa, exhibits anti-inflammatory, antitumor, and antioxidative properties. Although its precise mode of action has not been elucidated so far, studies have shown that chemopreventive action of curcuma might be due to its ability to induce apoptosis (programmed cell death) in cancer cells. This original study was conducted in order to estimate whether curcuma enhances the radiation sensitivity of cancer cells. For this purpose, curcuma (concentrations ranging from 0 to 200 microM) was applied to human cancer cell cultures (HeLa, K-562 and IM-9) with or without X-irradiation (doses comprised between 0 and 8 Gy). Cell proliferation was monitored by trypan blue exclusion. For the estimation of apoptosis, changes in cell morphology and flow cytometry analysis (DNA content and presence of the sub-G1 peak) were performed. Microscopic examination of the curcuma-treated cells (with concentrations above 100 microM) showed a characteristic morphology of apoptosis. Furthermore, cells treated with curcuma exhibited a sub-G1 peak from which the magnitude was proportional to the concentration of curcuma. X-irradiation alone induced polyploidisation and apoptosis of the three cell lines, proportional to the doses of irradiation with a marked difference in radiation sensitivity between the cell lines (IM-9 < K-562 < HELA). However, when radiation and curcuma were applied together, our results showed that in HELA, K-562 and IM-9, curcuma showed a radiation sensitising effect only at the dose of 200 micro M. This result may open a perspective of synergical therapy at the condition to also address the intrinsic toxicity of curcuma on normal cells.

Mouse one-cell embryos undergoing a radiation-induced G2 arrest may re-enter S-phase in the absence of cytokinesis.

PCC (premature chromosome condensation) can be used for visualizing and scoring damage induced by radiation in the chromatin of cells undergoing a G1 or G2 arrest. A method involving the fusion of irradiated single embryonic cells with single MI oocytes was used to induce PCC in mouse zygotes of the BALB/c strain, which suffer a drastic G2 arrest after X-irradiation (dose used 2.5 Gy). Other G2-arrested embryos were exposed in vitro to the phosphatase inhibitor calyculin A. Both methods furnished excellent chromosome preparations of the G2-arrested embryos. The mean number of chromosome fragments did not change significantly during G2 arrest, suggesting that zygotes of this strain are unable to repair DNA damage leading to such aberrations. Forty to fifty percent of the irradiated embryos were unable to cleave after G2 arrest and remained blocked at the one-cell stage for a few days before dying. PCC preparations obtained from such embryos suggested that about 30% of them had undergone a late mitosis not followed by cytokinesis and had entered a new DNA synthesis. These results are discussed in the light of recent observations in irradiated human cells deficient in the p53/14-3-3sigma pathway.

Imprinting of the G(s)alpha gene GNAS1 in the pathogenesis of acromegaly.

Approximately 40% of growth hormone-secreting pituitary adenomas have somatic mutations in the GNAS1 gene (the so-called gsp oncogene). These mutations at codon 201 or codon 227 constitutively activate the alpha subunit of the adenylate cyclase-stimulating G protein G(s). GNAS1 is subject to a complex pattern of genomic imprinting, its various promoters directing the production of maternally, paternally, and biallelically derived gene products. Transcripts encoding G(s)alpha are biallelically derived in most human tissues. Despite this, we show here that in 21 out of 22 gsp-positive somatotroph adenomas, the mutation had occurred on the maternal allele. To investigate the reason for this allelic bias, we also analyzed GNAS1 imprinting in the normal adult pituitary and found that G(s)alpha is monoallelically expressed from the maternal allele in this tissue. We further show that this monoallelic expression of G(s)alpha is frequently relaxed in somatotroph tumors, both in those that have gsp mutations and in those that do not. These findings imply a possible role for loss of G(s)alpha imprinting during pituitary somatotroph tumorigenesis and also suggest that G(s)alpha imprinting is regulated separately from that of the other GNAS1 products, NESP55 and XLalphas, imprinting of which is retained in these tumors.

Radiation-induced chromosome aberrations in guinea-pig growing oocytes, and their relation to follicular atresia.

The female guinea-pig has been shown to represent a good model to investigate the genetic hazard of ionizing radiation in humans. The sensitivity of the guinea-pig oocytes to radiation-induced chromosome aberrations was, therefore, studied at different stages of oocyte and follicular growth. The sensitivity of oocytes enclosed in small follicles (15 weeks before ovulation) was found to be low and comparable to that of immature oocytes present at birth. The sensitivity of growing oocytes remained low and almost constant until 3 weeks before ovulation, from which time it began to increase. The most dramatic increase of sensitivity occurred during the last week preceding ovulation: about 90% of oocytes X-irradiated with 4Gy, 2 days before ovulation showed one or more chromatid interchanges, as compared to 20% for those irradiated with the same dose 1 week earlier. A comparison of our results with those found by others in the mouse shows that considerable differences of sensitivity exist between oocytes of these two species irradiated at similar stages of development. The possible reasons for these differences are discussed.

CT in the selection of patients with abdominal or pelvic sarcoma for reoperative surgery.

BACKGROUND: Retroperitoneal or visceral sarcoma may recur with disease limited to the abdomen and pelvis. In this clinical situation, further surgical treatments in an attempt to control the disease may be appropriate. CT is used to help select patients for additional surgical interventions. STUDY DESIGN: Preoperative abdominal and pelvic CT scans of 33 patients with recurrent sarcoma were reviewed retrospectively. All patients underwent reoperative surgery and, when appropriate, perioperative intraperitoneal chemotherapy. Patients were divided into two groups according to survival and disease status: alive with no evidence of disease (n = 7) and alive with disease or dead of disease (n = 26). Twenty-two CT indices were studied retrospectively for each patient and evaluated statistically. RESULTS: The presence of large (greater than 5 cm) tumor volume in 3 of the 13 abdominopelvic regions resulted in a significant difference in the prognosis between the groups of patients. These findings included tumor in the left lower quadrant (p = 0.032), tumor in the pelvis (p = 0.008), and tumor in the distal jejunum (p = 0.032). Two other CT indices that showed a significant difference in survival between the groups were involvement of five abdominopelvic regions or fewer (p = 0.008) and a peritoneal cancer index of 15 or less (p = 0.03). A statistical approach using a tree-structured diagram showed that patients with tumor diameter greater than 5 cm in the pelvis accompanied by tumor involvement of more than one segment of small bowel had a 0% probability of postoperative disease-free survival. In contrast, patients with tumor diameter less than 5 cm in the pelvis on CT had an 86% probability of disease-free survival. CONCLUSIONS: For patients with recurrent sarcoma, selection criteria were generated by a preoperative CT of the abdomen and pelvis. In this disease, CT was a reliable diagnostic test for predicting benefit from further surgical interventions and should be used in the future to help select patients for an aggressive versus a palliative approach.

Preimplantation development of giant triploid zygotes in the mouse.

Giant oocytes or two-cell embryos have been reported in various mammalian species. They may arise during multiplication of oogonia, after fusion of two oogonia or, more probably, when nuclear division is not accompanied by cytoplasmic division. The ultimate fate of these giant embryos is not well known. In our laboratory, giant two-cell mouse embryos have been occasionally observed. Recently, we observed two giant one-cell zygotes in the same species. Both showed two female pronuclei and one male pronucleus, as well as two second polar bodies localized at opposite poles of the embryo. These two giant zygotes showed normal viability and developmental capacity. Their triploid nature was confirmed by cytogenetic analysis. In order to study this interesting phenomenon in more detail, we produced giant oocytes containing two germinal vesicles by cell fusion and cultured them in vitro. About one third of them extruded two first polar bodies; in the second group only one polar body was observed, whilst the last group was without polar bodies. When parthenogenetically activated, the consistent answer analogical to that observed in "in vivo" oocytes was only observed when oocytes with two polar bodies were activated. The implication for IVF technologies is discussed.

Histone H1 kinase activity in one-cell mouse embryos blocked in the G2 phase by X-irradiation.

The activation of the p34cdc2/cyclin B complex is responsible for driving the cell cycle from the G2- to the M-phase. To investigate the effects of irradiation on the activity of the p34cdc2/cyclin B complex in preimplantation embryos, we irradiated one-cell mouse embryos with 2.5 Gy of X-rays at the early pronuclear stage, and measured the fluctuations of histone H1 kinase activity (a biochemical indicator of the kinase activity of the p34cdc2) at different times during the radiation-induced G2-arrest. BALB/c embryos were chosen for these experiments, since earlier results obtained in our laboratory had shown that such a treatment induces a G2-arrest of about 20 hours in more than 90% of the embryos. Our data showed that histone H1 kinase activity of irradiated embryos remained at a very low level during the period of G2-arrest. The level of activity found during late division of the G2-arrested embryos was also significantly lower in comparison with that of control embryos or irradiated embryos dividing without delay. All together, our results suggest that a) low levels of histone H1 kinase activity are sufficient for the division of one-cell embryos, b) there could be a link between the levels of histone H1 kinase activity in mitosis and the health status of the embryo.

Histone H1 kinase activity in ovulated oocytes.

The level of kinase activity of cdkl is known to be high during metaphase of the two meioses. In this experiment, histone H1 kinase activity (which is known to reflect cdk1 activity) was assayed in BALB/c mouse ovulated oocytes at various timepoints after ovulation. Histone H1 kinase activity in ovulated oocytes was stable up to 37 hours after ovulation. After that time, histone H1 kinase activity significantly decreased suggesting that cdkl might be degraded after this period of time if the ovulated oocyte is not fertilised.

Absence of activating mutations in the GnRH receptor gene in human pituitary gonadotroph adenomas.

The monoclonal origin of gonadotropin-secreting pituitary adenomas has been well demonstrated but only few molecular abnormalities have so far been recognized in these tumors. For many years, several authors have suggested a role for GnRH and/or GnRH receptors (GnRH-R) in the development of these pituitary adenomas. To test the hypothesis that mutant genes encoding a constitutively activated GnRH-R might be involved in the pathogenesis of these tumors, the sequence of the GnRH-R gene was analyzed in tumoral pituitary tissue obtained from ten patients (six female, four male). The pituitary gonadotropin-secreting adenoma was associated with in vivo hypersecretion of FSH, LH and/or free alpha-subunit (n = 7) or was clinically silent (normal plasma levels of gonadotropins or free alpha-subunit, n = 3). In all cases, immunocytochemical studies of the removed adenoma confirmed their gonadotroph nature by revealing positivity for FSH, LH and/or alpha-subunit. Genomic DNA was extracted from the pathological tissue obtained at neurosurgery. Eight sequencing primers were used to amplify the three exons of the GnRH-R gene from tumoral DNA. The entire coding sequence of the GnRH-R gene was sequenced in the ten adenomas. No mutation was found in any of the tumor specimens examined. In conclusion, mutations in the GnRH receptor coding sequence occur infrequently if at all in gonadotropin-secreting pituitary adenomas.

Heated intraoperative intraperitoneal mitomycin C and early postoperative intraperitoneal 5-fluorouracil: pharmacokinetic studies.

PURPOSE: The purpose of this study was to report the pharmacokinetics of heated intraoperative intraperitoneal mitomycin C (MMC) and to analyze the impact of heat, extent of peritoneal resections, and effect of intraoperative hyperthermic chemotherapy on the pharmacological properties of the peritoneal plasma barrier. METHODS: Sixty patients with peritoneal carcinomatosis were included in a phase I/II study combining cytoreductive surgery with 2 h of heated intraperitoneal mitomycin C in an intraoperative lavage technique and one cycle of early postoperative 5-fluorouracil (5-FU) given on postoperative days 1-5. Three pharmacokinetic analyses were performed: (1) pharmacokinetics of heated intraoperative intraperitoneal MMC was determined for 18 patients by sampling peritoneal fluid, plasma, and urine during the 2-h procedure; (2) impact of peritoneal resections on MMC pharmacokinetics was assessed by comparing a group of patients who underwent < or = 1 peritonectomy procedure (minimal surgery) to a group of patients who underwent > or = 2 peritonectomy procedures (extensive surgery), and (3) effects of heated intraoperative intraperitoneal chemotherapy on the pharmacokinetics of early postoperative intraperitoneal 5-FU by comparing a group of patients treated with heated intraoperative intraperitoneal MMC to a control group who did not receive heated intraoperative intraperitoneal chemotherapy. RESULTS: The mean dose of heated intraoperative intraperitoneal MMC per patient was 22.5+/-7.1 mg (12.9+/-3.8 mg/m2). Drug absorption from perfusate was 14.3+/-2.7 mg. The mean aeras under the curve (AUC) for perfusate and plasma were, respectively, 340+/-138 and 15+/-4 microg/ml x min. The mean AUC peritoneal fluid/plasma ratio was 23.5+/-5.8. Patients who underwent extensive peritoneal resections exhibited a significantly (p = 0.037; Wilcoxon rank test) increased peak plasma concentration of MMC, a significantly (p = 0.029) increased AUC of plasma concentrations and a significantly (p = 0.034) decreased peritoneal fluid/plasma AUC ratio. Pharmacokinetic studies of early postoperative intraperitoneal 5-FU showed no significant difference in plasma AUC, perfusate AUC and AUC ratio between patients who received and those who did not receive heated intraoperative intraperitoneal MMC. CONCLUSIONS: Heated intraoperative intraperitoneal chemotherapy achieves high peritoneal concentrations of MMC with limited systemic absorption. Systemic drug absorption during heated intraoperative intraperitoneal chemotherapy is increased when extensive peritoneal resections are performed, but such slight increases are unlikely to change the risk of systemic drug toxicities. Heated intraoperative intraperitoneal chemotherapy does not alter the pharmacokinetics of early postoperative intraperitoneal 5-FU.

Hyperthermic intraperitoneal doxorubicin: pharmacokinetics, metabolism, and tissue distribution in a rat model.

BACKGROUND: The cytotoxic effect of several anticancer agents, including doxorubicin, can be enhanced by hyperthermia. The purpose of this study was to evaluate the effect of hyperthermia on the pharmacokinetics, metabolism, and tissue distribution of intraperitoneal (i.p.) doxorubicin in a rodent model. METHODS: Doxorubicin was given i.p. to 20 Sprague-Dawley rats at a dose of 2 mg/kg over 60 min. Rats were randomized into two groups according to the temperature of the peritoneal perfusate: group NT received normothermic (37 degrees C) i.p. doxorubicin; group HT received hyperthermic (43 degrees C) i.p. doxorubicin. During the course of i.p. chemotherapy, peritoneal fluid and blood were sampled every 10 min. At the end of the procedure, rats were sacrificed and tissue samples (liver, spleen, small bowel, omentum, bladder, diaphragm, abdominal wall, heart) were collected. Concentrations of doxorubicin and its aglycone metabolites were determined in peritoneal fluid, plasma, and tissues by HPLC. RESULTS: No significant differences in areas under the curve (AUC) of peritoneal fluid doxorubicin and plasma doxorubicin were found between group NT and group HT. AUC ratios (AUC peritoneal fluid/AUC blood) were 87.9 for group NT and 82.9 for group HT. Group HT exhibited increased doxorubicin concentrations for all intraabdominal tissues. These differences were significant for spleen (P = 0.03), small bowel (P = 0.03), and omentum (P = 0.03). Doxorubicin aglycone was detected in plasma of both groups within the first 10 min of the procedure. There was a significant (P < 0.001) increase in plasma aglycone AUC for group HT when compared with group NT. Group HT exhibited increased aglycone concentration for all tissues. This difference was significant for liver (P < 0.001) and bladder (P < 0.001). CONCLUSION: Hyperthermia did not affect significantly the pharmacokinetics of i.p. doxorubicin. Tissue concentrations of doxorubicin in small bowel, omentum, and spleen were significantly increased when the drug was administered by hyperthermic i.p. perfusion. Hyperthermia increased significantly the doxorubicin aglycone concentrations in plasma, liver, and bladder.

Pharmacokinetics of intraperitoneal gemcitabine in a rat model.

BACKGROUND: Gemcitabine (2'-2' difluorodeoxycytidine) has been shown to possess a broad spectrum of antitumor activity against various malignancies, particularly pancreatic carcinoma. For cancers occurring within the abdominal cavity, the advantage of intraperitoneal (i.p.) chemotherapy over intravenous (i.v.) chemotherapy is the high drug concentration that can be achieved locally. In addition, the cytotoxic effect of several anticancer agents can be enhanced by hyperthermia. Using a rat model, this study was designed to compare i.p. vs i.v. gemcitabine and to evaluate the effect of hyperthermia on i.p. gemcitabine. METHODS: In the first phase of this study, 18 Sprague Dawley rats were given a single dose of gemcitabine then randomized into three groups according to dose and route of delivery of chemotherapy (12.5 mg/kg--i.v., 12.5 mg/kg--i.p. or 125 mg/kg--i.p.). In a separate experiment (phase 2), 12 Sprague Dawley rats were given a continuous i.p. perfusion of gemcitabine (12.5 mg/kg in 150 mL total perfusate) and randomized into two groups according to the temperature of the peritoneal perfusate (normothermic or hyperthermic). During the course of both experiments, peritoneal fluid and blood were sampled using a standardized protocol. At the end of the procedure the rats were sacrificed and all urine was extracted. Selected tissue samples were taken from rats in the second phase of the study. The concentration of gemcitabine in all samples was determined by high performance liquid chromatography (HPLC). RESULTS: When gemcitabine was delivered at 12.5 mg/kg (phase 1) the area under the curve (AUC) was significantly higher with i.p. administration as compared to i.v. administration (P = 0.001). The AUC ratio (AUC peritoneal fluid/AUC plasma) was 12.5+/-3.2 for i.p. delivery as opposed to 0.2+/-0.2 for i.v. delivery (P = 0.0002). The AUC ratio for i.p. gemcitabine at 125 mg/kg was 26.8+/-5.8. Although there was no significant difference in drug concentrations between samples from the normothermic and hyperthermic groups, all tissue samples (except stomach) in the hyperthermic group exhibited increased gemcitabine concentrations. CONCLUSION: These experiments demonstrated that the exposure of peritoneal surfaces to gemcitabine is significantly increased with i.p. gemcitabine. Intraabdominal hyperthermia had no significant effect on the pharmacokinetics of i.p. gemcitabine but there was evidence of increased absorption of gemcitabine in most intraabdominal tissues. Due to the likelihood of a high incidence of microscopic residual disease after resection of a pancreatic carcinoma, clinical studies to evaluate i.p. hyperthermic gemcitabine may be indicated.

Malignant peritoneal mesothelioma. Case-report demonstrating pitfalls of diagnostic laparoscopy.

Patients with peritoneal mesothelioma present with abdominal distension and clinical syndrome of debilitating ascites. Cytology of the peritoneal fluid obtained by laparocentesis often does not result in a diagnosis. Laparoscopy with biopsy of peritoneal nodules is a valuable method by which a histological diagnosis is established. However laparoscopy can greatly complicate the management of peritoneal mesothelioma by facilitating tumor dissemination to port sites. The patient presented was treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy. Although palliation of intra-abdominal tumor and ascites was achieved, port sites-disease required extensive resection of the abdominal wall. Our experience with this patient suggests that if a malignant source of ascites is suspected and a diagnosis is not obtained by paracentesis, laparoscopy should be used to establish a diagnosis. However, trocars should only be placed along the midline of the abdominal wall so that port sites can be excised at the time of cytoreductive surgery. This diagnostic strategy is applicable to the majority of patients undergoing laparoscopy when there is known or suspected intraabdominal malignancy.

Effects of intra-abdominal pressure on pharmacokinetics and tissue distribution of doxorubicin after intraperitoneal administration.

Increased hydrostatic pressure in solid tumor nodules decreases the penetration of chemotherapy into cancerous tissue. This is true for both i.v. and i.p. chemotherapy. The purpose of this study was to determine the influence of increasing intra-abdominal pressures on the pharmacokinetics and tissue distribution of doxorubicin administered i.p. Four groups of 10 Sprague Dawley rats were given i.p. doxorubicin (4 mg/kg) during 60 min combined with no pressure (control), 10, 20 and 30 mm Hg pressures. During the course of i.p. chemotherapy, peritoneal fluid and blood were sampled. Two other groups of 10 rats received the same dose of i.p. doxorubicin during 10 min combined with no pressure and 30 mm Hg pressure. At the end of experiments animals were sacrificed and tissue samples were collected. Doxorubicin concentrations in peritoneal fluid, plasma and tissues were determined by HPLC. Pharmacokinetic studies showed that increased intra-abdominal pressures of 10, 20 and 30 mm Hg did not alter peritoneal fluid AUCs, the plasma AUCs and the peak ratios of i.p. doxorubicin when compared to the control group (no pressure). A subset analysis of high intra-abdominal pressure groups (20 and 30 mm Hg) versus control group showed statistically significant differences in peritoneal fluid AUCs, plasma AUCs and AUC (peritoneal fluid/plasma) ratios. For all groups, the highest tissue concentrations of doxorubicin were found in tissues associated with the parietal peritoneum: the bladder, the abdominal wall and the diaphragm. After 10 min of i.p. chemotherapy, the group treated with 30 mm Hg pressure showed a significant increase of doxorubicin concentrations in these tissues as compared to the control group. This significant increase of tissue doxorubicin concentrations was not found after 60 min of pressure with i.p. chemotherapy; prolonged intra-abdominal pressure was associated with a high incidence of intestinal ischemia. In conclusion, intra-abdominal pressure of 20 and 30 mm Hg significantly decreased the AUC ratios of i.p. doxorubicin but concomitantly increased tissue uptake of doxorubicin in bladder, diaphragm and abdominal wall during the first 10 min of i.p. administration. These findings may have significance in the design of improved strategies to increase tissue concentrations of chemotherapy delivered by an i.p. route.