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PubMed1975

[In-vitro testing of the sensitivity of mammary carcinoma cells to cytostatic drugs (author's transl)].

In-vitro sensitivity to cystostatic agents was tested in 137 cases of breast carcinoma, with 125 tests being analysable. Inhibition of in-vitro incorporation of 3H-uridine or 3H-thymidine into RNA or DNA of the original tumour cells after incubation with antineoplastic substances was used as the index for the in-vivo sensitivity of the tumour. 30% of the carcinoma cells were sensitive in-vitro, 70% resistant. About 75% of sensitive cancers were sensitive against several agents. Cyclophosphamide proved to be most effective in-vitro: it was tested via 4-hydroxycyclophosphamide or 4-hydroperoxycyclophosphamide. There was a correlation between histological type and in-vitro sensitivity of the cancer, as well as between proliferative activity and in-vitro sensitivity in that proliferation-active tumours were more frequently sensitive in-vitro than proliferation-poor ones. Primary tumours and metastases of the same patient frequently showed different sensitivity. In some cases the development of resistance against cytostatic drugs was demonstrated during treatment. Testing tumours against combinations of cytostatic drugs demonstrated an additive effect of the antineoplastic substances in-vitro.

Antineoplastic Agents↗
PubMed2002

[Thrombelastographic coagulation analysis following in vitro and in vivo haemodilution with hydroxyethyl starch (HES)].

In the study presented the effects of in vitro hemodilution with HES on coagulation are compared with the effects of in vivo hemodilution using thrombelastography (TEG). The in vivo hemodilution was performed by the i. v. infusion of 1000 ml 6 % solution of hydroxyethyl starch HES (2 formulations with HES 130/0.4 and one formulation with HES 200/0.5) in healthy volunteers during 30 min. The in vitro hemodilution was performed with blood samples taken from the volunteers before the infusion was started. These samples were diluted with HES-solution until the same hemoglobin concentration measured at the end of the infusion was attained. The in vivo TEG-parameters remained in the reference range of the method, however all in vitro TEG-parameters are out of the range of normal values. The isolated interpretation of the in vitro data shows an impairment of blood coagulation. The shortening of the reaction time as an indicator for the initiation of blood clotting points to activated coagulation by in vivo hemodilution with HES, whereas in vitro the prolongation of the reaction time is indicative for retardation of clotting. The evaluation of the TEG-parameters and of other clotting parameters determined prior to the beginning of the infusion, at the end of the infusion and four hours after termination of the infusion of HES 130/0.4 and of HES 200/0.5 to healthy volunteers show alterations of blood coagulation parameters caused mainly by dilutional effects. The more pronounced alterations found in vitro cannot be interpreted as impairment of haemostasis in vivo. On the other hand, the likewise haemodilution in vitro causes an impairment of coagulation. Therefore, the effects of in vitro hemodilution with HES on coagulation differ qualitatively and quantitatively from the effects of in vivo hemodilution.

Adult↗
PubMed2000

Optimal pregnancy outcome in a minimal-stimulation in vitro fertilization program.

OBJECTIVE: We sought to provide a cost-beneficial approach to in vitro fertilization for infertile patients who could not afford the standard treatment with in vitro fertilization and to determine the optimal level of minimal ovarian stimulation to achieve acceptable pregnancy rates. STUDY DESIGN: We performed a retrospective cohort study of 216 patients who underwent "minimal stimulation" in vitro fertilization between January 1994 and December 1998. During the first half of this study, various minimal ovarian stimulation protocols were performed in our private, free-standing center for in vitro fertilization. More recently, more ovarian stimulation, including a 4-day protocol featuring gonadotropin-releasing hormone agonist flare (ultrashort flare), was used. Clinical pregnancy outcome, multiple gestation, complications, and maternal age were compared between the first and second halves of this study. RESULTS: The average ages of patients in the first half (phase 1) and the second half (phase 2) were similar, 32.4 +/- 0.3 versus 32.6 +/- 0.3 years, respectively. An average of 3.5 oocytes per retrieval was obtained in phase 1 versus 5.9 oocytes in phase 2. Failure to retrieve oocytes occurred in 3% of all cases. The mean number of embryos transferred per patient was 2.0 in phase 1 versus 2.4 in phase 2. In phase 1, 16.1% of patients failed to have viable embryos for transfer, in comparison with 9.7% in phase 2. The overall clinical pregnancy rate per retrieval was 16.9% in phase 1 versus 36. 6% in phase 2. Multiple gestation occurred in 5.0% of clinical pregnancies in phase 1 but increased to 33% in phase 2, with 9 sets of twins and 6 sets of triplets. The implantation rate was 9.3% for phase 1 versus 23.3% for phase 2. The clinical pregnancy rates per retrieval for phase 2 patients were 41.6% in women < or =34 years old and 25.6% for those > or =35 years old. No case of ovarian hyperstimulation syndrome was noted. CONCLUSIONS: Minimal ovarian stimulation in the setting of in vitro fertilization offers a cost-beneficial alternative to standard treatment with in vitro fertilization in infertile patients who are <35 years old and in women <40 years old who have adequate oocyte reserve. More stimulation improves outcome. Minimalstimulation in vitro fertilization provides an alternative for those patients who cannot afford standard in vitro fertilization or who are concerned with exposure to high dosages of fertility medications.

Cohort Studies↗
PubMed1994

Changes in gamma-aminobutyrate type A receptor subunit mRNAs, translation product expression, and receptor function during neuronal maturation in vitro.

The amounts of mRNAs encoding alpha 1, alpha 6, beta 2, beta 3, gamma 2, and delta subunits of gamma-aminobutyrate type A (GABAA) receptors and the gold immunolabeling density of their translation products were monitored during the growth of neonatal rat granule cells in primary culture. We investigated possible correlations (i) between temporal changes in mRNA content and expression density of their respective translation products and (ii) between the quantitative changes of receptor subunit expression, the GABA EC50 for Cl- channel activation, and diazepam efficacy in modulating GABA action on the Cl- channels. At 3 days in vitro, the amount of GABAA receptor subunit mRNAs and the expression of their respective translation products were very low. During the next 2 weeks both parameters for every subunit studied increased asynchronously; moreover, at 14 days in vitro the sum of gamma 2 and delta subunit expression was smaller than the expression of the alpha 1 or alpha 6 or beta 2/beta 3 subunits. This suggests that during in vitro maturation each subunit may be regulated independently and invites speculation as to possible changes in specific GABAA receptor subtype abundance during development in vitro. The maximal current intensity elicited by GABA failed to increase from 5 to 14 days in vitro, though the amount of mRNA encoding various subunits and the expression density of their respective translation products increased. Thus, qualitative changes in the GABAA receptor subtypes expressed and/or abnormalities in the subunit assembly very likely account for the uniformity of the maximal current intensity elicited by GABA during in vitro development. Also, during maturation of neuronal cultures from 5 to 20 days in vitro the extent of the positive modulation of GABA action by diazepam decreased dramatically. This finding might be related to an increase in the abundance of GABAA receptors including the alpha 6 subunit and/or to the expression, during granule cell maturation in vitro, of GABAA receptors devoid of gamma 2 subunits.

Animals↗
PubMed2004

Permanent in vitro growth is associated with poor prognosis in head and neck cancer.

OBJECTIVE: The propensity of head and neck carcinomas to grow in vitro and to form a permanent cell line varies. It is not known whether the outcome of patients whose cancer gives rise to permanent in vitro growth differs from that of patients whose cancer cells fail to grow in vitro. The purpose of this study was to find out whether tumor cell capability for in vitro growth is associated with prognosis in head and neck cancer. MATERIAL AND METHODS: The study group consisted of 30 patients treated for head and neck cancer at the University Central Hospital of Turku between 1987 and 1994, and whose tumor samples had produced a permanent cell line in our laboratory. A control group was selected from patients treated during the same time period and with the same protocols in the same department. The controls were selected on the basis of similar tumor localization, TNM status, histological grade, age, gender and general condition. Tumor samples from 14 of the 30 control patients were also cultured, but did not result in a permanent cell line. The median follow-up time was 54 months in the study group and 52 months in the control group. RESULTS: The 3-year survival rate of the patients whose cancer gave rise to in vitro growth was only 19%, compared to 68% among the controls (p = 0.001). In a multivariate analysis the propensity of cancer cells to grow in vitro had independent prognostic value, the relative risk of death (RR) being 1.95 (95% CI 1.11-3.42) when compared to cancers that did not produce a cell line. Of the other factors tested, only the primary tumor size (RR 1.75; 95% CI 0.97-3.16) and the blood hemoglobin level at diagnosis (RR 0.97; 95% CI 0.95-1.01) were possibly independently associated with survival. CONCLUSIONS: The results suggest that the capability of cancer cells for in vitro growth has prognostic significance in head and neck cancer, and that cancer cells that are able to survive and grow in in vitro conditions behave aggressively in vivo. The independence of cancer cells from the paracrine signals produced by the neighboring host cells may enhance cancer cell survival and the metastatic potential in vivo.

Adult↗
PubMed2001

The effects of meiosis activating sterol on in-vitro maturation and fertilization of human oocytes from stimulated and unstimulated ovaries.

The object of this study was to assess functional maturation in vitro by obtaining data on the fertilization and embryonic competence of human oocytes with or without exposure to meiosis activating sterol (MAS) during maturation in vitro. Immature oocytes were either collected from unstimulated patients with polycystic ovaries (PCO) during gynaecological surgery, or were donated by patients undergoing a cycle of intracytoplasmic sperm injection (ICSI) treatment including ovarian stimulation with gonadotrophins. PCO oocytes had variable cumulus cover, which was retained during culture while those from ICSI patients were cultured without cumulus. The study included 119 oocytes from PCO patients and 72 from ICSI patients. The oocytes were allowed to mature in vitro for up to 46 h in the presence or absence of MAS. Mature oocytes were inseminated by ICSI with fertile donor spermatozoa and embryo development was monitored in vitro. MAS (30 microg/ml) significantly increased the survival of oocytes from PCO patients (P < 0.01) but did not significantly affect the proportion completing maturation in vitro. For the ICSI patients, >90% of oocytes survived in all culture groups, regardless of MAS addition, however MAS (10 or 30 microg/ml) significantly increased the proportion of oocytes maturing in vitro (P < 0.05). The apparent tendency towards improved subsequent development in vitro will require larger numbers of oocytes for evaluation. Oocytes from ICSI patients matured more rapidly in vitro than those from PCO patients. Our results show positive effects of MAS on human oocytes, confirming previous data in mice. This work may have implications for the future clinical application of IVM.

Adult↗
PubMed1997

Fermentation in human subjects of nonstarch polysaccharides in mixed diets, but not in a barley fiber concentrate, could be predicted by in vitro fermentation using human fecal inocula.

The fermentation of nonstarch polysaccharides (NSP) contained in a low fiber diet, two high fiber diets high or low in protein, and a barley fiber concentrate was determined in balance experiments in six women and in an in vitro batch system using fecal inocula obtained from these same women. In vitro fermentations were performed with fiber residues prepared from duplicates of the fiber-containing foods consumed during the balance trials. Fermentation of total NSP in humans was 83.8 +/- 0.9% (low fiber diet), 61.8 +/- 3.6% (high fiber diet high in protein), 59.2 +/- 3. 9% (high fiber diet low in protein) and 31.2 +/- 7.4% (barley fiber concentrate). Fermentation in vitro differed from fermentation in humans by -4.0 +/- 1.6% (low fiber diet, P < 0.05,), 4.9 +/- 3.7% (high fiber diet high in protein), 8.8 +/- 3.0% (high fiber diet low in protein, P < 0.01) and 19.7 +/- 8.0% (barley fiber concentrate, P < 0.05). Differences between in vivo and in vitro fermentation were most pronounced for NSP-glucose, i.e., cellulose. Production of short-chain fatty acids in vitro corresponded to the fermentability of NSP. The yield of short-chain fatty acids per gram of fermented NSP was similar for the diets (8.8-9.4 mmol) but lower for the barley fiber concentrate (7.4 mmol, P < 0.05). Although differences between the fermentation measured in humans and in vitro were significant for two diets, the magnitude of the differences was such that fermentation of NSP in mixed diets could be predicted with sufficient accuracy in vitro, whereas agreement between the fermentation in vivo and in vitro of NSP in the barley fiber concentrate was not satisfactory.

Adult↗
PubMed1994

Developmental competence of domestic cat embryos fertilized in vivo versus in vitro.

Development of in vitro-fertilized (IVF) cat embryos was compared to that of naturally produced cat embryos in vivo and in vitro. To obtain in vivo-fertilized embryos, queens were mated three times daily on the second and third days of natural estrus and ovariohysterectomized at 64, 76, 100, 124, or 148 h after the first copulation. Embryos were flushed from the reproductive tract, evaluated for developmental stage, and cultured. For IVF, oocytes from gonadotropin-stimulated queens were inseminated with electroejaculated cat sperm in Ham's F-10 and evaluated for fertilization (cleavage to > or = 2 cells) at 30 h. In vitro development of embryos fertilized in vivo (n = 109) and in vitro (n = 46) was evaluated every 24 h for up to 10 days. High-quality embryos recovered at 64, 76, 100, 124, and 148 h after the first copulation were typically 1 to 2 cells (13 of 20), 5 to 8 cells (18 of 28), 9 to 16 cells (14 of 24), morulae (15 of 21), and compact morulae (11 of 18), respectively, suggesting blastomere cleavage once per day in vivo after the first three rapid cell divisions. A similar developmental rate to the morula stage (p > or = 0.05) was achieved in vitro by embryos derived from both in vitro and in vivo fertilization. Additionally, the proportion (p > or = 0.05) of in vivo-generated embryos (2 to 16 cells) that developed to morulae (64 of 83; 77.1%) was similar to that of IVF embryos (28 of 46; 60.9%). However, none of the IVF embryos (0/46), but 70.6% (77 of 109) of the in vivo-produced embryos, achieved blastocyst formation in culture (p < or = 0.05). Furthermore, 66.2% (51 of 77) of these blastocysts exhibited zona hatching. Incidence of morula and blastocyst formation in the in vivo group was influenced by stage of the embryo at collection. Embryos that were at the 9- to 16-cell stage at recovery were more likely (p < or = 0.05) to achieve morula or blastocyst status and emerge from the zona pellucida than younger-stage counterparts. In summary, the in vivo and in vitro growth rate of cat embryos produced after natural mating was comparable to that of embryos fertilized and cultured in vitro. However, developmental ability to the blastocyst stage was superior for embryos produced in vivo after natural mating.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2004

Status and prospects of in vitro tests in risk assessment.

According to the new chemicals policy of the European Union (EU), most chemicals, i.e. the 20,000 chemicals manufactured or imported at 1-10 tons annually, should be tested primarily by using in vitro methods. Also, for other chemicals, the use of in vitro methods is encouraged in the testing strategies given in the draft EU legislation. However, the validation and international acceptance of in vitro tests has been slow. Only recently has the OECD approved four new in vitro test methods, validated by the European Centre for the Validation of Alternative Methods. An analysis of ten randomly selected risk assessment reports of the EU Existing Chemicals Risk Assessment Programme showed that in vitro studies, for example, on cytotoxicity to different cell cultures, cell transformation, metabolism and skin penetration (a total of 115 studies) were used for the assessments. Key metabolic pathways and mechanisms of toxicity have been elucidated, for some chemicals, by using in vitro methods. On the other hand, the results of in vitro studies were regarded as secondary or unreliable in some cases. For several toxic endpoints, in vitro methods will probably serve as screening tools and for mechanistic studies, while target organ toxicity or physiologically regulated adverse effects caused by long-term exposure are difficult to observe without the use of animal models.

Animal Testing Alternatives↗
PubMed1983

Evaluation of changes in the secretion of corticotrophin releasing activity using the isolated rat hypothalamus incubated in vitro.

The secretion of corticotrophin releasing activity (CRA) from the isolated rat hypothalamus incubated in vitro was investigated under various conditions of incubation and of pretreatment of donor animals providing hypothalami. Media from hypothalamic incubations were assayed for CRA by a validated double in-vitro bioassay technique which differentiates CRA from vasopressin. A circadian rhythm was found in the secretion of CRA in vitro from isolated hypothalami obtained from animals killed at different times of the day. Secretion of CRA increased significantly at 19.00 h (dusk) compared with the secretion rate at 07.00 h, in synchrony with a rise in plasma corticosterone levels. In addition, both plasma corticosterone concentrations and CRA secretion in vitro were higher at 07.00 h than at 19.00 h after exposure of the donor animals to a reversed light cycle for 7-10 days. Hypothalami obtained from animals chronically treated with betamethasone in the drinking water showed a diminished secretion of CRA in vitro. Exposure of untreated animals to ether vapour for 2 min immediately before death significantly increased the subsequent secretion of CRA in vitro. Ether exposure did not significantly affect the secretion of CRA in vitro from hypothalami of betamethasone-treated rats. There was a close correlation between plasma corticosterone levels and in-vitro CRA release after these treatments. The results suggest that the secretion of CRA examined in this way is a phenomenon which can reflect the changes which occur in the activity of the hypothalamo-pituitary-adrenal system in vivo during the 24-h cycle, after glucocorticoid treatment and after ether stress.

Animals↗
PubMed2001

In vitro studies on biological effects of fibrous minerals.

Asbestos substitutes have been used recently in industrial various applications. Since certain asbestos substitutes have similar characteristics of asbestos, they require urgent in vitro and in vivo evaluation of these asbestos substitutes prior to occupational applications. Though in vitro studies do not offer precise assessment of toxicity of the fibers, it is possible to provide useful information as to the biological effects of asbestos and its substitutes. This review articles described the findings of in vitro experiments in investigation of biological effects of asbestos and man made mineral fibers (MMMF) and their correlation with in vivo assays; 1. Cytotoxicity, geometry and dimension of fibers. 2. In vitro biological effects of fibers on a mass basis and a numerical basis. 3. Mechanism of cytotoxicity, carcinogenecity and cell proliferation including in vitro cytokines production. The relationships between the in vitro and the in vivo biological effects of fibers do not always coincide. Therefore, safety of the fibers must be assessed in both in vivo and in vitro using an inert fiber as negative control. Additionally, evaluation of safety of these fibers in vitro must be conducted in comparable concentrations, sizes and numbers of fibers for used in in vivo experiments.

Animals↗
PubMed1986

Comparison of in vitro and in vivo rates of collagen synthesis in normal and damaged lung tissue.

The rate of collagen synthesis was measured in vivo and in vitro in both normal and damaged mouse lung tissue. Acute lung damage was induced by the administration of butylated hydroxytoluene (BHT). The production of labeled hydroxyproline, following the administration of labeled proline, was used as an index of collagen production. Total and labeled hydroxyproline in normal and damaged lung tissue were solubilized equally following digestion with purified collagenase. Assuming that the extent of hydroxylation was not altered, this indicated that hydroxyproline was an accurate index of collagen content and production in damaged as well as normal lung tissue. The quantities of hydroxyproline formed at various times both in vivo and in vitro were calculated from the specific activity of free proline in lung tissue. The specific activity of free proline in normal and damaged lung tissue remained constant in vivo for at least 90 minutes after the intravenous injection of labeled proline. Hydroxyproline production was a linear function of time for up to 90 minutes in vivo and three hours in vitro. The in vivo rate of hydroxyproline production was significantly greater than the in vitro rate in lung tissue from similarly treated mice. The difference ranged from five-fold in normal lung tissue to eight-fold in lung tissue damaged by the administration of BHT. Comparable differences were seen between the in vivo and in vitro rates of non-collagen protein synthesis. Despite these differences in rates, the percentage of total protein synthesis committed to collagen in vivo was the same as in vitro in normal lung, and identical increases were seen in damaged lung. These data show that in vivo rates of both collagen and non-collagen protein synthesis are significantly higher than those measured in mouse lung tissue in vitro. Although the relative increases in collagen synthesis that occur in response to lung damage are larger in vivo, measurements of collagen synthesis in vitro do accurately reflect the general changes that accompany acute lung damage.

Animals↗
PubMed1999

Effectiveness of in vitro fertilization with intracytoplasmic sperm injection for severe male infertility.

BACKGROUND: In its 1993 report the Canadian Royal Commission on New Reproductive Technologies challenged the effectiveness of in vitro fertilization for severe male infertility. To address the Commission's concern, the authors compared the relative effectiveness of in vitro fertilization combined with intracytoplasmic sperm injection for severe male infertility and conventional in vitro fertilization for complete tubal occlusion in women. METHODS: This historical cohort study was done at the PROCREA Fertility Centre, a private tertiary human reproduction centre in Montreal. Three groups of infertile couples were compared: 122 couples with severe male infertility treated by in vitro fertilization with intracytoplasmic injection of fresh sperm from ejaculate (group 1); 27 couples with obstructive azoospermia treated by in vitro fertilization with intracytoplasmic injection of epididymal sperm (collected by microepididymal or percutaneous epididymal sperm aspiration) (group 2); and 98 couples with tubal factor infertility (bilateral tubal occlusion) treated with conventional in vitro fertilization (with sperm from ejaculate) (group 3). The main outcomes measured were rates of fertilization, pregnancy, clinical pregnancy and implantation. RESULTS: Pregnancy rates per started cycle were 35%, 40% and 34% for groups 1, 2 and 3 respectively. When prognostic factors were controlled for, none of the outcome measures differed significantly between the 3 groups. INTERPRETATION: In vitro fertilization with intracytoplasmic injection of sperm from the ejaculate or the epididymis is as effective for treating severe male infertility as conventional in vitro fertilization is for treating complete occlusion of the fallopian tubes in women.

Adult↗
PubMed2003

Feasibility study to evaluate the correlation between results of a candidate in vitro assay and established in vivo assays for potency determination of Newcastle disease vaccines.

A Newcastle disease virus antigen quantification assay has been developed at CIDC-Lelystad as a candidate in vitro potency test for inactivated Newcastle disease vaccines. In studies performed at CIDC-Lelystad, a high correlation was demonstrated between the results of this candidate in vitro potency assay and the results of the serological potency assay (European Pharmacopoeia monograph 0870; test A). Furthermore, a high correlation between the serological data (Haemagglutination Inhibition-antibody titres) and clinical protection after challenge was demonstrated. The aim of the feasibility study was to confirm the correlation between the results obtained using the candidate in vitro potency assay and the results from both the in vivo potency assays currently prescribed in Ph Eur monograph 0870, in different laboratories and to determine whether a large-scale validation study of the in vitro method should ensue. In the feasibility study three Official Medicines Control Laboratories tested the potency of 5 different inactivated Newcastle disease vaccines and one experimental vaccine, using both of the in vivo methods described in the European Pharmacopoeia and the candidate in vitro method. The 6 vaccine batches represented a quantitative range of Newcastle disease virus antigen content and were produced by different manufacturers. Statistical evaluation of all results indicated that a satisfactory correlation was found in all laboratories between the two types of in vivo tests currently in place, and the candidate in vitro test. An excellent reproducibility of the proposed in vitro method was observed with respect to the ranking of the vaccines included in this study. It is concluded that the results of this feasibility study indicate that a large-scale collaborative study can be organised to validate the in vitro method and the suitability of the reference preparation.

Animal Use Alternatives↗
PubMed1991

Comparison of in vitro RBC labeling with the UltraTag RBC kit versus in vivo labeling.

This study compared cardiac-gated equilibrium blood-pool imaging studies using in vitro technetium-99m- (99mTc) labeled red blood cells (RBCs) prepared with the UltraTag RBC kit to in vivo labeling with stannous (pyro- and trimeta-) phosphates. The in vitro labeling procedure takes approximately 25 min and does not require centrifugation to separate free from bound 99mTc. Imaging studies were performed in 30 patients using the in vitro labeling procedure and in 30 patients with in vivo labeling. Regions of interest were placed over the center of the left ventricle, inferior and lateral to the left ventricle (background), and over the right midlung. The mean +/- s.e. in vitro RBC labeling efficiency was 98.5 +/- 0.2%. The heart-to-background ratios were significantly higher with in vitro labeling. The heart-to-background ratios, averaged among two blinded reviewers, were 4.6 and 3.4 for the in vitro and in vivo methods, respectively. The heart-to-lung ratio was generally higher with the in vitro procedure (3.6) than that observed with the in vivo method (3.2) but failed to attain statistical significance (p = 0.059). These results demonstrate the superiority of the in vitro labeling procedure over in vivo labeling for gated equilibrium blood-pool imaging.

Erythrocytes↗
PubMedDate not supplied

Proton MR spectroscopy of squamous cell carcinoma of the extracranial head and neck: in vitro and in vivo studies.

PURPOSE: To determine the ability of in vitro one-dimensional and two-dimensional proton MR spectroscopy to help differentiate squamous cell carcinoma of the extracranial head and neck from normal tissues and to correlate the in vitro observations with clinical studies. METHODS: In vitro 1-D and 2-D correlated proton MR spectroscopy (11 T) was performed in tissue specimens of squamous cell carcinoma of the head and neck (n = 19), in normal tissue (n = 13), in metastatic cervical lymph nodes (n = 3), and in a squamous cell carcinoma cell line. In vivo 1-D proton MR spectroscopy (1.5 T) was performed in patients with squamous cell carcinoma (n = 7) and in healthy volunteers (n = 7). The ratio of the areas under the choline (Cho) and creatine (Cr) resonances were calculated for 1-D proton MR spectra for the in vitro tissue studies and correlated with the in vivo studies. Data from in vitro 2-D correlated spectroscopy were analyzed for differences in the presence or absence of various metabolites in samples of tumor and normal tissue. Statistical analysis consisted of 2 x 2 factorial repeated measures analysis of variance (ANOVA), discriminate analysis, and chi2 test. RESULTS: The mean in vitro 1-D proton MR spectroscopic Cho/Cr ratio was significantly higher in tumor than in normal tissue. The difference between the mean ratios appeared to increase with increasing echo time. All in vivo tumor Cho/Cr ratios were greater than the calculated mean in vitro tumor ratio, whereas six of the seven volunteers had no detectable Cho and Cr resonances. Two-dimensional correlated MR spectroscopic data revealed that a variety of amino acids have a significantly greater likelihood of being detected in tumor than in normal tissues. CONCLUSIONS: One-dimensional and 2-D proton MR spectroscopy can help differentiate primary squamous cell carcinoma and nodal metastases containing squamous cell carcinoma from normal tissue both in vitro and in vivo. In addition, 2-D spectroscopy can help identify the presence of certain amino acids in squamous cell carcinoma that are not detected in normal tissue.

Carcinoma, Squamous Cell↗
PubMed1999

Morphology and mechanical function of long-term in vitro engineered cartilage.

Cartilage tissue can be engineered in vitro with articular chondrocytes and poly(glycolic acid) nonwoven scaffolds as previously shown over 12 weeks in vitro. This study addressed whether engineered cartilage would further evolve and approach natural cartilage in extracellular matrix organization and biomechanical properties, especially aggregate modulus through longer term in vitro cultivation. Cellularity, cell size, compressive modulus, and permeability of the in vitro engineered cartilage stabilized within the 12-week cultivation time and remained at the same levels as those of natural cartilage thereafter. The linear range of the stress-strain curve was from 0 to a strain value between 5 and 10% for all the engineered cartilage tissues that were in vitro cultured for longer than 2 weeks, which was the same linear range for natural cartilage. The aggregate modulus further increased from week 12 to week 20 and remained approximately the same value thereafter during a 25-week in vitro cultivation. The aggregate modulus of the engineered cartilage reached 179+/-9 kPa after 20 weeks of in vitro cultivation, which was 40% that of natural articular cartilage. To our knowledge this is the highest aggregate modulus value yet reported of any in vitro engineered cartilage tissue.

Animals↗
PubMed1992

High in vitro-in vivo correlation of drug response using sponge-gel-supported three-dimensional histoculture and the MTT end point.

The in vitro sponge-gel-supported three-dimensional histoculture chemosensitivity assay (Hoffman assay) allows the in vivo-like culture of human tumors. In this study, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H tetrazolium bromide (MTT) end point was applied to the Hoffman assay in an attempt to increase in vitro-in vivo correlation. The chemosensitivities of 16 human tumor lines were determined in vitro by the histoculture assay, and retrospectively correlated to their in vivo chemosensitivity as xenografts in nude mice. The in vitro test was considered to be positive if tumor-cell MTT reduction activity was lowered by more than 50%. The cutoff drug concentrations to determine sensitivity in vitro were determined for mitomycin C, doxorubicin, 5-fluorouracil and cisplatin. Using these cutoff drug concentrations in vitro we found, as a function of time of exposure, a strong correlation between serum drug concentrations found in nude mice given maximum tolerated doses and drug concentrations found in the histoculture media in vitro, thereby establishing a relationship between the amounts of drugs to which tumors were exposed in vivo and in vitro. The overall correlation rate of the efficacy results of the drug-response assay to in vivo chemosensitivities was 89.8%, with 90.0% true-positive and 89.7% true-negative rates, 81.7% sensitivity and 94.6% specificity, thereby indicating potential clinical use for tumor histoculture with the MTT end point.

Animals↗