The impact of embryonic development and endometrial maturity on the timing of implantation.

To gain insight into the peri-implantation period in the human and to answer the question whether timing of nidation is dependent on the stage of embryonic development, endometrial maturation, or a possible dialogue between the two. Seventy-five women underwent embryo transfer (ET) throughout 93 cycles. Thirty-three ETs resulted in viable pregnancies and deliveries. These pregnancy cycles were used for embryonic signal detection. Embryos of identical age were transferred onto hormonally and histologically defined endometria of different maturational stages (days 15 to 19). Human chorionic gonadotropin (hCG) was measured by a hypersensitive chemiluminescence assay in maternal serum every 1 to 5 days to detect the first embryonic signal. Individual linear regressions of hCG versus embryonic age and endometrial maturation were performed on 33 viable pregnancy cycles (r2 = 90.5% to 99.9%, P less than 0.02 to 0.002). First signal detection was restricted to an embryonic age of 7.1 +/- 0.28 (mean +/- SD) days (range 6.6 to 7.4) irrespective of endometrial maturation. The pattern of hCG detection was triphasic, described by a sigmoidal curve with the maximal slope corresponding to an hCG doubling time of 15.9 hours. Embryo transfers on cycle day 19 had a steeper slope of hCG detection than days 15 and 16 (P less than 0.05). First embryonic signal detection (presumed window of implantation) extends between cycle days 20 and 24. Implantation is dependent on embryonic age and is independent of endometrial maturation within this window. The timing and sigmoidal pattern of hCG detection coincides with structural changes of the implantation bed. The steeper slope of late ETs may represent a compensatory mechanism for late maternal recognition of pregnancy for corpus luteum rescue.


The effect of egg yolk medium on human sperm binding in the hemizona assay.

To evaluate, using the hemizona assay (HZA), whether egg yolk treatment of human sperm enhances binding to the human zona pellucida in vitro and to determine whether such a treatment is as efficient as the standard swim-up procedure for promoting sperm binding ability. Ejaculates were divided into aliquots and half incubated at 37 degrees C for 21 hours in standard culture medium or combined with buffered medium containing chicken egg yolk and stored at 4 degrees C for 21 hours. A second set of ejaculates were split and processed by a standard 1-hour rise alone or treated with egg yolk medium. University teaching hospital. Two healthy sperm donors. The number of sperm tightly bound to the hemizona were measured and compared between the groups. A significant increase (P less than 0.0001) in hemizona binding (n = 46) for egg yolk treatment (90.1 +/- 9.8; range 7 to 258) as compared with standard culture medium (53.0 +/- 8.8; range 0 to 228) was observed. Similarly, a significant increase (P less than 0.0001) in binding (n = 37) for egg yolk treatment (74.9 +/- 8.2; range 7 to 219) as compared with samples obtained with a sperm rise (37.1 +/- 5.7; range 2 to 122). Treatment of human spermatozoa with an egg yolk medium at 4 degrees C overnight significantly increases sperm binding in the HZA.


A prospective controlled evaluation of TEST-yolk buffer in the preparation of sperm for human in vitro fertilization in suspected cases of male infertility.

To evaluate sperm preincubation in tes and tris (TEST)-yolk buffer as a potential enhancing agent of fertilizing capacity of sperm during human in vitro fertilization (IVF). Oocytes obtained during IVF were divided into two groups: one group fertilized with TEST-yolk buffer-treated sperm and the other group with standard-prepared sperm. The University of Southern California IVF Program. Thirty-nine couples with suspected male factor infertility undergoing IVF. Preinsemination incubation of sperm in TEST-yolk buffer for 24 hours. Fertilization rates in vitro. TEST-yolk buffer-treated sperm fertilized 140 of 241 oocytes (58%), whereas control sperm fertilized 108 of 251 oocytes (43%). Of four couples who had previously failed to fertilize during IVF, one fertilized with both specimens and three fertilized with TEST-yolk buffer-treated sperm only. TEST-yolk buffer pretreatment of sperm for 24 hours results in higher fertilization rates during IVF among suspected male factor patients.


Prediction of in vitro fertilization outcome by sperm penetration assay with TEST-yolk buffer preincubation.

To evaluate sperm penetration assay (SPA) value as a screening tool before in vitro fertilization (IVF). Follow-up study comparing sperm variables and IVF outcome. Infertile couples in an academic research environment. Two hundred forty-one infertile couples scheduled for IVF. Sperm penetrating assay with cold Tes-TRIS (TEST) Yolk buffer semen preincubation and IVF. Percent of egg penetration recoded into poor and good category (0% to 20%, 21% to 100%) and compared with fertilization, embryo transfer, and pregnancy rate (PR) in IVF, as well as sperm count motility and morphology. Sperm penetrating assay predicted fertilization with a high negative (74%) and positive (82%) predictive rate and good specificity value (0.96). One of 31 patients in the poor SPA category (3%) fertilized less than 50% of eggs; no pregnancy occurred. In the good SPA category, 87 of 210 patients (41%) fertilized greater than or equal to 50% of eggs with 34.3% PR. Sperm penetrating assay correlated better with fertilization rate than did sperm count and motility but not morphology. Sperm penetrating assay is a useful screening assay before IVF together with sperm morphology.


Randomized, prospective comparison of luteal leuprolide acetate and gonadotropins versus clomiphene citrate and gonadotropins in 408 first cycles of in vitro fertilization.

To compare luteal phase leuprolide acetate (LA) initiated pituitary down regulation followed by human menopausal gonadotropins (hMG) versus clomiphene citrate (CC) and hMG for follicular recruitment and oocyte maturation before in vitro fertilization (IVF). Randomized, prospective comparison in first cycles of IVF. University Hospital, a tertiary referral center offering assisted reproductive technologies. Participants were couples undergoing their first ever cycle of IVF and consenting to participation in the trial. Luteal phase initiated LA/hMG was associated with a lower probability of cycle cancellation, improved folliculogenesis, and a higher probability of embryo transfer (ET) compared with CC/hMG alone. Implantation rates were not different. A higher rate of ET with LA/hMG suggests that gonadotropin-releasing hormone agonist for the induction of folliculogenesis before IVF may be appropriate.


Improved pregnancy rate after transfer of embryos grown in human fallopian tubal cell coculture.

To evaluate the embryonic behavior in vitro and the pregnancy and implantation rates of embryos grown in a human ampullary cell coculture system. In a prospective study, two pronuclei embryos were cultured on human ampullary feeder layers up to the two to six-cell and blastocyst stages and replaced either as tubal, uterine, or sequential transfers. Assisted reproductive technology program in a university-based hospital. Fifty women with a mean age of 35.6 years who went through a single coculture cycle. Thirty of the patients were admitted for in vitro fertilization (IVF) and 20 for tubal embryo transfer (TET). The overall clinical pregnancy rate (PR) for all 50 patients was 44% per cycle (IVF, 37%; TET, 55%) and the implantation rate was 31.8% (IVF, 31.0%; TET, 32.6%). Sixty-eight percent of pregnant patients were over 35 years, and 68% had two previously failed assisted reproduction cycles. Five of 9 patients who received sequential transfers became pregnant. Three of the 22 pregnancies aborted (2 after sequential transfer), and there was one ectopic. Overall, 88% of two to six-cell stage embryos were of good quality. The human ampullary coculture system produces better quality embryos, increased numbers of blastocysts with improved PRs and implantation rates. The beneficial effects of the feeder layer may be through the release of embryotrophic factors and detoxification of the medium by the cells. Coculture is a new concept in assisted reproduction and has tremendous potential in boosting conception rates by mimicking the in vivo environment.


The role of oocyte maturity in the treatment of infertility because of teratozoospermia and normozoospermia with gamete intrafallopian transfer.

To determine the effect of oocyte maturity on pregnancy rate (PR) in patients undergoing gamete intrafallopian transfer (GIFT) procedures for infertility and in whom male partners had either normozoospermia or teratozoospermia. A prospective study using a combination of clomiphene citrate and human menopausal gonadotropin for ovulation induction was carried out. Five hundred thirty-seven GIFT treatment cycles were analyzed, and 423 cycles yielded four or more oocytes. Patients were divided into two groups according to the sperm morphology: those with less than 14% normal forms and those with greater than 14% normal morphology (as judged by strict criteria). These two groups were divided into a further five subcategories depending on the number of metaphase II oocytes transferred. In the group less than 14% normal forms (category I; 4 metaphase I oocytes replaced), three pregnancies resulted from 33 cycles (9.09%), and in category V (4 metaphase II oocytes transferred) the PR was 15% (14/95) per cycle. In the group with greater than 14% normal forms, in category I, the PR was 16% (3/19) per cycle, and in category V, the PR was 33% (20/61) per cycle. The effect of morphology (less than 14% normal forms versus greater than 14% normal forms) on pregnancy outcome is significant (P = 0.0161). The overall effect of increasing the number of metaphase II oocytes on the pregnancy outcome was not significant (P = 0.1098). However, in the group with greater than 14% normal forms, there was a significant improvement in PR (P = 0.04) in category V. During this prospective study, it was shown that sperm morphology plays a significant role in the pregnancy outcome in a GIFT program.


Failure of intrauterine insemination in male immunological infertility in cases in which all spermatozoa are antibody-coated.

To determine if the overcoming of the cervical mucus barrier removes the interference of sperm-bound antibodies with fertility. Prospective case series. University-based intrauterine insemination (IUI) homologous program. Nineteen patients with all spermatozoa in the ejaculate coated by antisperm antibodies. As control group, 86 consecutive patients without antisperm antibodies, treated for oligoasthenozoospermia or mucus hostility. Intrauterine inseminations (at least 3 attempts per couple). The outcome of IUIs, demographic, and seminal parameters were compared between the two groups. No pregnancy occurred in the couples with male immunological infertility, treated by 110 IUIs. Twenty-three pregnancies occurred in 22 (25.6%) of the control group couples who were treated by 411 IUIs. In the group of patients without antisperm antibodies, we demonstrated that the pregnancy rate (PR)/couple in oligoasthenozoospermia without teratozoospermia was similar to that achieved in normozoospermia (35% versus 38.9%), whereas it was significantly affected by teratozoospermia (3.6%). Only three patients with antisperm antibodies had teratozoospermia. Comparing the PR per couple and per cycle between the two groups of patients (with and without antisperm antibodies), excluding the patients with teratozoospermia, significant differences resulted (P less than 0.005 and P less than 0.005, respectively). The motile sperm count was not significantly different between the two groups, which also resulted to be homogeneous for demographic data. Moreover, the motile sperm count was not different between the patients with and without antisperm antibodies, who had successful IUI. The analysis of this trial suggests that the failure of IUI in the treatment of male immunological infertility is imputable to antisperm antibodies when they involve all spermatozoa, regardless of semen quality.


Identification of human sperm antigens reacting with antisperm antibodies from sera and genital tract secretions.

To identify sperm antigens reacting with antisperm antibodies relevant in human infertility. The reactions of separated sperm antigens with antibodies present in sera and genital tract secretions from infertile and fertile females and males were examined by immunoblotting techniques. The patients were followed in an outpatient setting of a hospital clinic. One hundred consecutive infertile males and females, referred for determinations of antisperm antibodies, comprised the study group. Fifty hospital and faculty employees with proven fertility served as a control group. A high proportion of sera from fertile and infertile humans contained antibodies reacting with at least one sperm antigen. However, two discrete bands of antigenic proteins with molecular weights of 44 and 72 kd reacted significantly more frequently with serum antibodies from infertile females than from fertile females. No apparent correlation could be demonstrated between any particular antigen and serum antibodies from infertile males. Nevertheless, antigenic proteins of 62 kd were identified as the major sperm antigens reacting with antibodies present in seminal plasmas from infertile males. The major sperm antigens reacting with systemic antibodies differ from the antigens recognized by local antisperm antibodies. Sperm antigens exhibiting relative molecular weights of 62 kd are major antigens reactive with local antisperm antibodies from infertile humans.


High progesterone concentrations induce acrosome reaction with a low cytotoxic effect.

To determine the optimal conditions to obtain live acrosome-reacted spermatozoa for micromanipulation. Experiments were performed to determine time and dose-dependent effects of calcium ionophore A23187 or steroids on acrosome reaction of fertile donor sperm. The percentages of total reacted and live reacted spermatozoa were assessed with the peanut agglutinin lectin procedure. Incubation with 1 mmol/L progesterone (P) induced 48% +/- 17% acrosome reaction after 6 hours. Motility and viability remained high (49% +/- 3% and 70% +/- 2%, respectively) and thus the percentage of live reacted spermatozoa was 27% +/- 5%. Incubation with A23187 (5 mumol/L for 30 minutes) gave similar results for the percentage of live reacted spermatozoa (26% +/- 4%) but with a lower motility and viability (25% +/- 7% and 53% +/- 2%, respectively; P less than 0.05). These results show that high concentration of P is an effective way to induce acrosome reaction in preparation for micromanipulation.


Unilateral obstruction of the vas deferens caused by childhood inguinal herniorrhaphy in male infertility patients.

To study the incidence, diagnosis, and treatment of unilateral obstruction of the vas deferens caused by inguinal herniorrhaphy (IH) during childhood. Retrospective. Kyoto University Hospital. Unilateral obstruction of the vas deferens after IH was diagnosed and treated in 10 of 724 subfertile patients. Reanastomosis of the vas deferens using a microsurgical two-layer technique. Follow-up seminal analysis of the patients and the occurrence of pregnancy in their wives. The incidence of unilateral vas deferens obstruction caused by IH was 26.7% for subfertile patients with a history of IH during childhood. Unilateral vas deferens obstruction was detected through palpation of the scrotal vas deferens in 7 of the 10 patients. After vasovasostomy, the semen quality improved in 5 patients, and pregnancy was achieved by 2 patients. The incidence of vas deferens obstruction was unexpectedly high in subfertile patients with a history of IH during childhood. Careful palpation of the scrotal content was a useful and noninvasive method to diagnose unilateral vas deferens obstruction, and microsurgical vasovasostomy was treatment of choice.


Body weight, body mass index, and age: predictors of menotropin dose and cycle outcome in polycystic ovarian syndrome?

Whereas the dose of hMG is significantly correlated with both BMI and BW, commencing the more obese patient on higher hMG doses is not justified in view of the cancellation of cycles from over-responsiveness in the more obese patients started on higher hMG dosage regimens. If the more obese patient is slow to respond, however, a greater degree of clinical freedom may be exercised to increase the dose. The ultimate outcome of the cycle is not related to BMI, BW, or the dose of hMG used.


Evaluation of Astroglide, a new vaginal lubricant: effects of length of exposure and concentration on sperm motility.

Traditional vaginal lubricants have been shown to adversely affect sperm motility. Astroglide, a new vaginal lubricant, and K-Y Jelly were tested at varying concentrations to assess their suitability for infertility patients requiring a lubricant. The vaginal lubricants tested impaired sperm motility in a concentration-dependent but not time-dependent manner. We conclude that all traditional vaginal lubricants should be avoided in patients desiring conception. Future studies should attempt to mimic in vivo conditions and focus on concentration-dependent effects.


Flow cytometric quantitation of the expression of membrane cofactor protein as a marker for the human sperm acrosome reaction.

A mAb (TRA-2-10, IgG1) to an embryonal carcinoma cell line (2102ep) that recognizes an antigen termed membrane cofactor protein (CD 46, TLX antigen) binds to human sperm after chemical induction of acrosomal loss by Ca2+ ionophore. An indirect immunofluorescence assay was developed in which sperm membrane cofactor protein was detected by flow cytometry on acrosome-reacted living human sperm. The expression of the membrane cofactor protein antigen on acrosome-reacted sperm may represent a marker that can be used in a rapid, quantitative, and reproducible flow cytometric assay for the evaluation of human sperm acrosomal loss.


Comparison of results obtained with human serum and a protein solution as a supplement for in vitro fertilization culture medium.

A prospective controlled study was performed to compare the PRs obtained after use of a uniform IVF culture medium containing a pasteurized serum protein solution or patient serum. The ongoing PRs per ET in the serum and the protein solution group were 32% and 28%, respectively (not significant). Culture of supernumerary embryos showed blastocyst formation and even hatching with both supplements. The PR will not drop when this protein solution is used as a protein supplement in IVF culture medium instead of patient serum.


An improved needleholder for endoscopic knot tying.

A needle holder fitted with a distal and rotating hook is described. During endoscopic suturing, this hook grasps the thread and forms automatically a loop, through which the distal end of the thread is pulled to secure the knot. Endoscopic intracorporeal knot tying thus becomes easier and faster, especially in difficult situations.


Anti-proliferative effect on human pancreatic cancer cells of natural human tumour necrosis factor-beta combined with natural human interferon-alpha or interferon-gamma.

The anti-proliferative effects of natural cytokines, human tumour necrosis factor-beta, natural human interferon-alpha and natural human interferon-gamma, on three human pancreatic cancer cell lines (PANC-1, MIA PaCa-2 and BxPC-3) were investigated in vitro. The anti-proliferative effect was determined using the dye uptake method and analysed for synergism by the median effect principle. Tumour necrosis factor-beta, as a single agent, had little anti-proliferative effect on any of the three cell lines, whereas interferon-alpha and interferon-gamma exhibited a strong anti-proliferative effect against two cell lines (MIA PaCa-2 and BxPC-3) and one cell line (BxPC-3), respectively. When tumour necrosis factor-beta and interferon-alpha were administered together (ratio 1:1), a synergistic effect was observed against PANC-1 cells. The combination of tumour necrosis factor-beta and interferon-gamma (ratio 10:1) was synergistic against both PANC-1 and MIA PaCa-2 cells. A synergistic anti-proliferative effect of tumour necrosis factor-beta and interferons was, therefore, observed even for cell lines that showed little biological response to each cytokine alone. The data suggest that some future improvement in the treatment of pancreatic cancer may be obtained by using combination cytokine therapy.


Effects of mexiletine on the haemodynamic responses to tracheal intubation.

The efficacy of intravenous mexiletine in attenuating the cardiovascular responses to laryngoscopy and tracheal intubation was studied in 30 normotensive patients undergoing elective surgery. The patients were randomly allocated to one of three treatment groups: saline (n = 10); 2 mg/kg mexiletine (n = 10); and 3 mg/kg mexiletine (n = 10). The placebo/mexiletine was administered immediately before induction of anaesthesia using 5 mg/kg thiopentone and tracheal intubation was facilitated with 0.2 mg/kg vecuronium; laryngoscopy lasting 30 s was attempted 2 min after induction of anaesthesia. All groups showed a significant (P less than 0.05) increase in mean arterial pressure and heart rate associated with tracheal intubation. The increase in mean arterial pressure was significantly (P less than 0.05) smaller in patients receiving 3 mg/kg mexiletine compared with those receiving either saline or 2 mg/kg mexiletine. There was no significant attenuation in heart rate in either of the mexiletine treatment groups compared with the saline group. It is concluded that 3 mg/kg mexiletine given intravenously provides a simple and effective method for attenuating the pressor response to laryngoscopy and tracheal intubation.


Multicentre clinical placebo-controlled study with buflomedil in the treatment of mild dementia of vascular origin.

A study was carried out in 73 male or female patients suffering from mild vascular dementia. The experimental protocol involved an initial run-in period (14 days) and subsequent double-blind, randomized treatment with 300 mg buflomedil or placebo given orally twice daily for 90 days. At the end of this treatment period, all patients received buflomedil for a further 90 days and, thereafter, patients received buflomedil or no further treatment for another 90 days. The efficacy of buflomedil was monitored using rating scales and neuropsychological tests. The findings of the study indicate that buflomedil improved the symptoms of vascular dementia; the most improvement was recorded in patients who had received buflomedil for the longest period. Inadequacy, cooperation, psycho-affective disorders, self-care and somatic complaints were positively influenced by buflomedil. The efficacy of buflomedil may be due to its effects on platelet aggregation and improvement in blood flow distribution to the ischaemic brain and oxygenation of brain tissue.


A double-blind, comparative study of zolpidem and placebo in the treatment of insomnia in elderly psychiatric in-patients.

The efficacy and tolerability of the imidazopyridine hypnotic, zolpidem, were investigated in 119 elderly psychiatric in-patients complaining of insomnia in a double-blind, parallel-group, placebo-controlled trial. After a 7-day placebo washout period, patients were randomized to receive 10 or 20 mg/day zolpidem, or placebo for 21 days; thereafter, all patients received placebo for 7 days. Sleep was assessed by patient observation on days 0, 1, 7, 14, 21, 22 and 28. Compared with placebo, 20 mg/day zolpidem significantly improved total duration of sleep between day 0 and day 21, and this was maintained at day 28. After 10 or 20 mg/day zolpidem, there was also a trend towards improvement in all other sleep parameters, which remained above baseline at day 28. Zolpidem was well tolerated with no withdrawal symptoms during the second 7-day placebo treatment period. Daytime drowsiness was reported in three patients receiving 20 mg/day zolpidem and in one receiving 10 mg/day zolpidem, but there was no significant increase in daytime drowsiness between days 0 and 21. Ataxia occurred in two, one and one patient, respectively, treated with 20 mg/day zolpidem, 10 mg/day zolpidem and placebo. The incidences of other adverse events or effects on clinical and laboratory parameters were minimal and similar in all three treatment groups. It is concluded that, in elderly psychiatric patients, 10 mg/day zolpidem can be used to treat insomnia and can be safely added to concomitant psychotropic treatment without inducing daytime drowsiness.


The safety and efficacy of zolpidem in insomniac patients: a long-term open study in general practice.

The safety and efficacy of 10 or 20 mg/day zolpidem, a new hypnotic belonging to the imidazopyridine class, were studied over a 180-day period in 96 patients with sleep disorders. The treatment was continued for a further 180 days by 49 of these patients. Follow-up information from 21 patients who discontinued treatment after 180 days showed no rebound insomnia or withdrawal signs. Efficacy of treatment with respect to reduction of sleep onset latency and number of nocturnal wakenings, and improvement in duration of sleep, quality of sleep and morning wakenings was found in nearly 90% of patients and was maintained in those patients who continued treatment for 360 days. This efficacy was achieved with a stable percentage of patients receiving 10 mg/day and 20 mg/day zolpidem from day 30 to the final visit. Zolpidem, therefore, has been shown to be an effective and safe hypnotic, and to be devoid of rebound and withdrawal effects.


Clinical improvement in ankylosing spondylitis with rifamycin SV infiltrations of peripheral joints.

In an open study, a new treatment modality was evaluated in 22 patients with active ankylosing spondylitis and compared with oral treatment. Patients were given a 10-week course of rifamycin SV infiltrations to all large peripheral joints, whether or not affected, and were followed for up to 12 months after the end of treatment. Clinical improvements observed at the end of the 10-week treatment cycle persisted for 12 months: morning stiffness (P less than 0.02); subjective pain (P less than 0.0001); Schober's test (P less than 0.006); hand-ground distance (P less than 0.001); erythrocyte sedimentation rate (P less than 0.001); and C-reactive protein (P less than 0.04). The number of painful joints became significantly lower at 6 (P less than 0.01) and 12 months (P less than 0.02) of the follow-up period. Oral administration of rifampin at three times the intra-articular dosage was devoid of any therapeutic activity. It is not known how treatment of peripheral joints influenced the inflammatory process at the level of the axial skeleton. These results must be considered preliminary due to the small number of patients and the short follow-up period, and because it was an open study.


Primary fibromyalgia syndrome and 5-hydroxy-L-tryptophan: a 90-day open study.

The efficacy and tolerability of 5-hydroxy-L-tryptophan (5-HTP) were studied in an open 90-day study in 50 patients affected by primary fibromyalgia syndrome. When all the clinical variables studied throughout the trial (number of tender points, anxiety, pain intensity, quality of sleep, fatigue) were compared with baseline results, they all showed a significant improvement (P less than 0.001). The overall evaluation of the patient condition assessed by the patient and the investigator indicated a 'good' or 'fair' clinical improvement in nearly 50% of the patients during the treatment period. A total of 15 (30%) patients reported side-effects but only one patient was withdrawn from the treatment for this reason. No abnormality in the laboratory evaluation was observed. It is concluded that 5-HTP is effective in improving the symptoms of primary fibromyalgia syndrome and that it maintains its efficacy throughout the 90-day period of treatment.


Does a dose of 40 micrograms/day prostaglandin E1 reduce creatinine clearance in a patient with diabetic nephropathy of the nephrotic type?

The case history of a woman, who at the age of 25 years on the birth of her second child was found to be diabetic, is reported. Over the subsequent 30 years the patient had been treated with insulin, the dose administered being monitored at regular intervals. At the age of 52 years, the patient was diagnosed as suffering from hypertension and diabetic nephropathy of the nephrotic type. The patient's condition gradually deteriorated and at 55 years of age 40 micrograms/day prostaglandin E1 was given intravenously for 84 days. Treatment resulted in a decline in urinary protein without a reduction in creatinine clearance. Renograms confirmed an improvement in the vascular and secretory phases of both kidneys.


Special natural cartilage polysaccharides for the treatment of sun-damaged skin in females.

In the present double-blind investigation, the effects of a new formulation of natural cartilage polysaccharides on sundamaged skin were studied in women aged 40-60 years. A group of 15 women were treated orally with 500 mg/day active substance (Vivida) for 90 days and a second group of 15 women received 500 mg/day placebo for 90 days. Clinical examinations after 45 and 90 days' treatment showed significant improvements in skin condition in the actively treated group but not in the placebo group (P less than 0.001). In the Vivida-treated patients, the epidermal thickness increased after 90 days from 0.11 mm to 0.29 mm, dermal thickness from 0.74 mm to 1.39 mm, skin elasticity index from 44% to 73% and the erythemal index decreased from 0.301 to 0.205. No changes were observed in the placebo group and no adverse effects were reported by either treatment group.


Chemical characterization of the dentin/adhesive interface by Fourier transform infrared photoacoustic spectroscopy.

Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the dentin surface. The purpose of this in vitro investigation was to characterize the chemical nature of the surface interaction between dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crowns of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6 mm x 2 mm, were prepared from these sectioned teeth. The exposed dentin surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm-1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the dentin surface was collected. This surface was primed according to manufacturer's instructions and spectra recorded of the primed surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to surface interactions between the adhesive and the dentin. Although early results do not indicate covalent bonding between the dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the dentin/adhesive interface.


Inhibition of microbial adherence and growth by various glass ionomers in vitro.

This study measured the in vitro inhibition of growth and adherence of five oral bacteria by glass-ionomer materials. Disks were prepared from two cavity liners and four restorative class materials, by use of Teflon plates with circular wells, five mm wide and two mm deep. The bacterial species tested included: A. viscosus, S. mitis, S. mutans, L. casei, and S. sanguis. Growth inhibition studies were performed by the spreading of 0.1 mL of standardized inocula over agar plates produced with selective media, followed by the direct application of glass-ionomer disks onto the agar. On other plates, disks were placed onto uninoculated agars for 48 h, followed by bacterial inoculation. All agar plates were incubated under optimal growth conditions for each bacterial species. The four restorative materials were also placed aseptically into sterilized bovine incisors and placed into sucrose containing broth media, inoculated with S. mutans for three days. Adhering materials were disclosed and scored. An ion-exchange electrode was used to measure fluoride release over a seven-day period for all six glass ionomers. The two cavity liners and two of the restorative materials produced the largest growth inhibition zones by direct contact. No growth inhibition occurred when the specimens were allowed to come into contact with the agars prior to inoculation. All four restorative materials reduced bacterial accumulations on enamel surfaces by over 80%. Elevations in short-term fluoride release levels were positively correlated with growth inhibition.


The effect of corrosive environment on the porcelain-to-metal bond--a fracture mechanics investigation.

Microcracks, flaws, and voids inside a metal-porcelain restoration may cause the restoration to fracture in service. Such cracks result in the concentration of stresses. The dynamic nature of the stresses due to mastication promotes crack growth. In addition, corrosive components of the oral environment enhance the growth rate. In the present investigation, fracture mechanics has been used to analyze the in vitro resistance to fracture of the porcelain-fused-to-metal restoration. The risk of a clinical failure of porcelain-fused-to-metal decreases with enlarged crack resistance (increasing work of fracture). The work of fracture represents an average of the energy for initiation and propagation of a crack through the interface separating porcelain and metal. This work also indicates a material's ability to stop a crack once it is moving. This study utilized the three-point bending test for the crack resistance measurement, and investigated one palladium and five base metal alloys. Corrosive components of the oral environment and the details of firing were of crucial importance for long-term bond stability.


Effects of dentin surface treatments on the shear bond strength of Vitrabond.

The influences of nine dentin surface treatments were evaluated on the shear bond strength of a new light-cured glass-ionomer cement (GIC) and on the SEM morphology of the treated dentin surfaces. The following treatments were performed: saline solution (control), NaOCl, acidic glycine, EDTA, malic acid, malic acid plus glycine, polyacrylic acid, tannic acid, and neutral+acidic oxalate solutions. Buccal dentin surfaces were polished with #320-grit abrasive paper, treated with one of the chemicals, washed, and air-dried. Cylindrical GIC samples were then applied to the dentin surface, stored in 100% humidity, and tested after 24 h. SEM observations demonstrated no effect of saline or NaOCl treatment on the smear layer but its complete removal with exposure of collagen fibrils after malic or malic acid plus glycine treatment. Partial removal of the smear layer occurred following glycine treatment and with tannic or polyacrylic acids. Complete removal of the smear layer was seen after EDTA or pyruvic acid treatment. Oxalate treatment produced a layer of crystals, which completely covered the dentin surface. Shear bond strength of GIC was significantly increased only by treatment with the oxalate solutions.


Microleakage comparison of dentin bonding systems with glass ionomer.

Glass-ionomer cements have been suggested as substitutes for dentin-bonded composites. This investigation was designed to compare microleakage of glass-ionomer restorations with that of dentin-bonded composite restorations. Eighty extracted human molars were used in this study. Class V cavities were prepared on the mesial and distal surfaces of each tooth. The distal cavities were restored with Ketac-Fil Glass Ionomer (ESPE). The mesial cavities were divided into four groups and treated with four different dentin bonding systems: Gluma (Columbus Dental), Tenure (two-part powder system; second version, Den-Mat), Scotchbond 2 (3M), and an experimental ferric oxalate system. The commercial materials were placed according to the manufacturers' instructions. The teeth were then thermocycled 3800 cycles between 5 degrees C and 55 degrees C, subjected to silver nitrate staining, and sectioned for microleakage evaluation by three evaluators on a scale of 0 to 4. The ferric oxalate system exhibited significantly less microleakage (median score = 1; Wilcoxon paired testing, p = 0.01) than the glass ionomer (median score = 3). The other dentin bonding systems were similar in microleakage to the glass ionomer (median score = 3).


Relationship between bond strength and microleakage measured in the same Class I restorations.

Microleakage measurements were made by use of a pressurized fluid method in Class I restorations prepared in extracted human teeth just prior to measuring the tensile bond strengths of the same restorations. The restorative materials included dentin bonding systems that are applied to smear layers as well as those which remove the smear layer. A light-cured glass-ionomer cement was also included. The results demonstrated that there was an inverse relationship between dentin bond strength and microleakage in some materials and that the bond strengths made to three-dimensional Class I cavities were much lower than those made to flat dentin surfaces. Measurement of microleakage by fluid filtration had no apparent effect on bond strength.


International distribution of dental materials publications and patents.

International patterns of research and development in the field of restorative dental materials were examined with data on publications (1981-85) and patents (1979-88). It was found that United States-based authors produced approximately one-half of all dental materials journal articles published worldwide, while US inventors had nearly the same share of the US dental materials patents. During the periods studied, the share of US patents in dental materials awarded to US inventors declined, while the share of US patents awarded to Japanese inventors rose. The role of the United States in research (as measured by journal articles) remained stable. Nations differed in the degree to which their researchers specialized in particular research areas. US-based authors and inventors were relatively over-represented in prosthetic materials and under-represented in dental cements, an area in which the British and the Japanese concentrated more of their activity. There was some, but not complete, agreement in the patterns of national specialization as indexed by patent and publication data. When dental materials data were compared with data for broader fields of science and technology, important differences were found. For publications, US-based authors displayed greater dominance in dental materials than in the fields of dentistry, chemistry, and materials science. US-based inventors' share of US dental materials patents was smaller than their share of all US patents. These analyses demonstrated that it was possible to use indicators derived from publication and patent data files to conduct insightful studies of a discrete specialty of science and technology.


Accuracy testing of three-dimensional digitizing systems.

An accuracy test designed as a standard for digital occlusal wear measurement devices was applied to such a device designed by the authors. The test was used for quantitative determination of measurement error for a given angle of tangential contact with the inclined planes of the surface being measured. Using known dimensions of the digitizer contact tip and of a precision steel sphere, we determined trigonometrically the error in the Z-axis measurement due to the slope of any point on the surface of the sphere. These values were used for a point-by-point correction of data obtained from actual digitization of the sphere. The corrected values would equal zero if no mechanical source of error existed. These values, then, quantitatively indicated the accuracy (in microns) of the device as a function of the slope of the measurement point. The results indicated a linear relationship between surface slope angle and measurement error for the device tested.


Cytotoxicity evaluation of a new radiopaque resin additive--triphenyl bismuth.

Triphenyl bismuth (Ph3Bi) is a promising new additive for making biomedical resins visible on x-ray images. We evaluated the cytotoxicity of Ph3Bi, both alone and as a component of a denture resin, as an initial step in determining its biocompatibility. These experimental materials were compared with several types of dental materials that are in current clinical use (PMMA denture acrylic resin, two photo-cured sealants, and two glass-ionomer cements). Human embryonic lung fibroblast tissue cultures (WI-38 cells) were exposed to 24-hour aqueous extracts of the materials. Changes in cell growth, cell viability, and the visual appearance of cells were used for the assessment of toxic response. Only a slight degree of cytotoxicity was observed for Ph3Bi, both alone and in combination with self-cured PMMA. All clinical materials showed a higher level of cytotoxicity than did Ph3Bi. The sealants and cements exhibited the most cytotoxicity and PMMA acrylic the least. The cytotoxicity of PMMA was elevated slightly by inclusion of Ph3Bi, probably due to decreased monomer conversion. When stored in water, the already low levels of cytotoxicity of both PMMA and PMMA with added Ph3Bi were reduced even further. From these results, we can predict a high level of safety for Ph3Bi as a radiopaque additive for biomedical resins. Any toxicity associated with Ph3Bi-containing resins can be reduced or avoided by prior extraction. Alternatively, curing conditions can be selected that would drive the polymerization reaction to a higher level of conversion.


Direct and indirect evaluation of posterior composite restorations at three years.

The purpose of this study was to compare the use of direct (USPHS) and indirect (M-L) systems of evaluating the occlusal wear of posterior composite restorations. Additionally, this study has utilized the USPHS method to compare the in vivo performance of posterior resin composite restorations made from four different visible-light-cured materials. Of the 202 restorations placed for this randomized clinical trial, only those restorations that were scored by both direct and indirect evaluation systems were included in these comparisons. Restorations were evaluated by two calibrated examiners from baseline to 36 months. While there were some differences noted among the four materials, the majority (99%) of the restorations evaluated in this study received "alpha" or "bravo" scores for all USPHS parameters, indicating acceptable in vivo performance. The results of this study also indicate that there was a consistent relationship between the direct (USPHS) and indirect (M-L scale) scoring systems. For those restorations that changed anatomic form scores, the mean wear at the alfa/bravo transition was 100 +/- 80 microns. By the 24-month recall examination, the use of the USPHS evaluation system category of anatomic form enabled examiners to differentiate restorations and materials that had experienced little occlusal wear from those that had experienced greater amounts of wear.


Precision of and new methods for testing in vitro alloy cytotoxicity.

Previous studies have utilized in vitro alloy cytotoxicity tests to evaluate dental casting alloys. The purposes of this study were to: (1) evaluate the precision of the optical density and visual tests previously used, (2) evaluate a new test measuring absorbance of solubilized formazan dyes, and (3) test the correlation between these tests for cytotoxicity. Balb/c 3T3 cells were plated in 24-well culture trays at 25,000 cells/cm2 around ten types of dental casting alloys (six samples/alloy) and incubated for 72 h. Cells were histochemically stained with MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide)/succinate for 2 h, then fixed, washed, and dried. Toxicity was measured by optical densitometer (OD) scanning, visual assessment, and 560-nm absorbance of DMSO-solubilized dyes. Measurements of rings of inhibition were not used, because they did not provide precise data, and correlated poorly with the other methods. The results were analyzed by ANOVA, Tukey intervals, and coefficients of variation (CV's). MTT required shorter incubation times for adequate staining, allowed for solubilization of the monolayers, and was less expensive than NBT (2,2'-di-p-nitro-phenyl-5,5'-diphenyl-3,3'-dimethoxy-[3,3'-dimethoxy-4,4 '-biphenylene] ditetrazolium chloride). Results showed that all three methods ranked alloy toxicities similarly (p = 0.05). The solubilization method was most discriminating due to lower CV's. Correlation between densitometer and solubilization methods was excellent (R2 = 0.96). Between-experiment CV's were generally less than 20%, and often less than 10%. Between-sample CV's were generally less than 20%.(ABSTRACT TRUNCATED AT 250 WORDS)


Cure profiles of visible-light-cured Class II composite restorations in vivo and in vitro.

The degrees of conversion of posterior composite material in Class II restorations performed in vivo and in vitro were studied by means of the Raman spectroscopy method. Class II restorations in 13 contralateral pairs of premolars were analyzed. The average difference of the ratio I 1610 cm-1/I 1640 cm-1 between the in vivo- and in vitro-performed restorations was 0.42. This indicates a higher grade of conversion in the in vivo situation.


Effect of loading conditions on bi-axial flexure strength of dental cements.

A ball-on-three-ball bi-axial flexure test was used to evaluate the flexure strengths of five kinds of dental cements (zinc phosphate, polycarboxylate, glass ionomer, silicate, and zinc oxide-eugenol cements). The bi-axial flexure strengths of zinc phosphate cement discs of variable dimensions were also measured to determine the size effects of test specimens. Finite element stress analyses were performed on disc specimens which were subjected to both a concentrated load and a uniformly distributed load. The observed values were compared with the theoretical value calculated by the finite element method. A ball-on-three-ball bi-axial flexure test could not be used for thicker specimens, since the fracture origin of these specimens is more likely to occur on the loaded side.


Dimensional stability of silicone-based impression materials.

This study attempts to demonstrate that the polymerization reaction is not the only factor that affects the shrinkage of silicone-based impression materials because evaporation of the constituents also contributes to the shrinkage. These factors can be evaluated by the study of time-dependent dimensional changes. This is shown both by chemical kinetics and by experimental testing of condensation and addition polymerizing impression materials with different viscosities. Comparison of the different materials shows that the two contributions, polymerization shrinkage, and evaporation shrinkage, can be assessed separately by analysis of the time-dependent shrinkage diagrams. The instability due to the polymerization reaction is complete after a few hours, but the contribution of the constituent evaporation, if present, can have a significant long-term role.


The colors of silver with silver nitrate staining in dental materials.

Silver nitrate has been used as a stain to study the permeability, degradation, and marginal integrity of dental composite restorations. The reagent results in various colors in the composite or marginal interface. So that the cause of these colors could be investigated, this study compared the appearances of the stained layers by light and electron microscopy. The results indicated that the colors could be explained by the distribution of silver particles ranging from minute colloidal particles (20 nm) in the composite or dentin, to clusters of large particles (0.1-1 micron) in marginal interfaces. The colors can be explained by the absorption and scattering of light by these particles. At elevated temperatures, fused concretions of silver formed in the composite subsurface, resulting in direct reflection of incident light. The colors which appear with silver nitrate staining may indicate the size and distribution of microporosity in the material.


Effect of HEMA on bonding to dentin.

The present study investigated the effectiveness of treating dentin with 2-hydroxyethyl methacrylate (HEMA) prior to application of an adhesive resin. The adhesive resin was 5% 4-methacryloxyethyl trimellitate anhydride (4-META) in methyl methacrylate (MMA) combined with poly-MMA powder. Polymerization of this resin was initiated by tri-n-butyl borane (TBB). Bovine dentin samples were ground with 600-grit Carbimet paper discs, and demineralized with either an aqueous solution of 10% citric acid/3% ferric chloride (10-3) or an aqueous solution of 10% citric acid (10-0). Improved bond strengths were achieved with HEMA treatment of bovine dentin samples, and improvement of bond strengths was dependent upon the time period of HEMA application. Scanning electron microscope (SEM) examination revealed the formation of a transitional zone of resin-reinforced dentin, termed the "hybrid" layer, in those specimens receiving 10-3 pre-treatment. The adhesive resin impregnated the exposed collagen bundles with which it entangled to create the "hybrid", essential in the attainment of high tensile bond strengths. Specimens pre-treated with 10-0 did not readily form "hybrid" layers. However, if HEMA application followed the 10-0 pre-treatment, "hybrids" were demonstrated on SEM, and bond strength increased to 13 MPa. The ferric ions in the 10-3 effectively improved the diffusivity of dentinal substrates, as did HEMA. This study indicates that HEMA applied to dentinal substrates enhances monomer diffusion and entanglement with dentinal components, and facilitates the formation of a "hybrid" layer.


A simple model of crack propagation in dental restorations.

Although natural teeth often exhibit microcracks, they rarely demonstrate bulk fracture. However, conventional full-crown restorations periodically exhibit failure due to fracture. Presented here is evaluation of a simple model of crack propagation that estimates crack growth during cyclic loading. A finite element model of a premolar tooth provides the tensile stresses adjacent to cusp loading. If the crack propagation rates for natural teeth, porcelain-fused-to-metal crowns and composite crowns are compared with the wear rates of their respective materials as determined in an artificial mouth, it is evident that the low wear rate of composites may predispose them to fracture. Natural teeth disperse occlusal stresses throughout the dentin so that the effect of high occlusal stress is minimized. Porcelain tends to wear the opposing dentition, which reduces areas of high occlusal stress. Composite, however, demonstrates crack propagation rates higher than those of either natural teeth or porcelain. This, in addition to its low wear rate, might predispose the material to fracture. This model should be used only as a qualitative indicator of fracture tendency. The high calculated crack propagation rates in composites may explain the observed clinical failures and microchipping at the area of occlusal contact, as noted in SEM analysis.


The relationship between monomer composition and physical properties of light-cured opaque resin.

Light-cured opaque resins were prepared using four types of monomer liquids and titanium dioxide powder. This study investigated the relationship between the monomer composition and the physical properties of light-cured opaque resin. Depth of cure, KHN, residual monomer eluent, and bond strength between the opaque resin and cobalt-chromium alloy were measured. The physical properties of triethyleneglycol dimethacrylate (TEGDMA)-based compositions were superior to those of methyl methacrylate (MMA)-based compositions. Viscosity of the opaque resin's liquid monomer was enhanced by 1,6-bis(methacryloxy-2-ethoxycarbonylamino)-2,4,4-trimeth ylhexane (UDMA). The TEGDMA-based light-cured opaque resins showed excellent physical properties and may be clinically acceptable in bonding prosthodontic composite to metal frameworks.


Determination of thermal properties of impression materials.

Residual strains are important for dimensional accuracy of impression materials. When these strains are being calculated, knowledge of thermophysical constants is needed. This paper describes determination of thermal diffusivity, thermal conductivity, specific heat, heat of polymerization rate, and total heat of polymerization. The first two constants mentioned were obtained from an experiment in which transient heat conductivity was studied. The evaluation was based on an analytical solution of this problem. The remaining constants were derived by means of standard differential scanning calorimetry, DSC. Results from accurate, cost-efficient methods are given for three silicones and one polyether.


In vitro bond strengths of three current dentin adhesives to primary and permanent teeth.

The in vitro shear bond strengths of three chemically different dentin bonding agents were tested between both permanent and deciduous dentin and their respective anterior composite filling materials. The effect of the post-mortem age of the teeth on bond strength was evaluated by comparison of fresh (extracted within 24 h) and old (extracted within 10 d) teeth. The results indicated that these materials bonded more strongly to the dentin of permanent than to deciduous teeth (8.8 +/- 4.9 MN/m2 vs. 6.2 +/- 4.8 MN/m2). The intermaterial comparison indicated that the bonds to dentin were strongest for Scotchbond 2 (12.3 +/- 4.4 MN/m2) followed by Tenure (6.9 +/- 3.3 MN/m2) and then Gluma (3.3 +/- 1.7 MM/m2). Both the above findings were shown to be statistically significant. The effect of time lapse after extraction of the teeth was not statistically significant.


The formation and properties of metal oxide poly(vinylphosphonic acid) cements.

Aqueous solutions of poly(vinylphosphonic acid) have been found to form polyelectrolyte cements with a wide range of metal oxides. Poly(vinylphosphonic acid), PVPA, has a structure similar to that of poly(acrylic acid), PAA, but contains pendant phosphonic acid,--P(O)(OH)2, groups in place of the carboxylic acid,--COOH, groups of the zinc polycarboxylate, and glass polyalkenoate cements. It is a stronger acid than PAA, with a greatly increased reactivity toward metal oxides. The physical and mechanical properties of a number of metal oxide PVPA cements were studied and compared with those of zinc polycarboxylate cements. The faster acting of the metal oxide PVPA cement seems to produce a cement that is less susceptible to early hydrolysis.


Microstructures of admixed amalgams produced from Pd-containing dispersants.

Blended Pd-containing dental amalgams were developed by substituting Pd for up to 20 w/o Ag or Cu in the Ag-Cu eutectic alloy. Melted ingots were lathe-comminuted to a particle size distribution of 1-45 microns. Alloy blends were created from two parts of a traditional amalgam and one part of experimental Ag-Cu-Pd particles. Amalgams with from 0.42 to 1.67 w/o Pd were fabricated by trituration of alloys and mercury at a Hg/alloy ratio of 1:1 with a mechanical triturator at 5000 rpm for 10 s and hand-condensed. XRD studies of these amalgams revealed the suppression of eta' (Cu6Sn5) phase with Pd addition and no gamma 2 (Sn8Hg) phase found. At 3.3 w/o Pd, the eta' (Cu6Sn5) concentration of the amalgam was below the detection limit of the instrumentation (1%). SEM micrographs revealed that reaction zones around eutectic particles decreased with increased Pd concentration.


Casting system effectiveness--measurement and theory.

Evaluating castability as a property of dental casting alloys is an unworkable concept, since any measure is demonstrably affected by several external factors. Casting System Effectiveness (CSE) is shown experimentally and theoretically to depend primarily upon the time taken for the advancing front to freeze. A spiral tube mold was used to measure casting length obtained under variations in casting temperature; this pattern is proposed as a standard measure of CSE. A Bernoulli 'free-fall' numerical model is shown to reproduce the principal features of such casting, with some evidence of viscosity limitation of the turbulent flow at long casting lengths. Direct measurement of melt velocities confirmed turbulent flow in the mold. A method is also suggested for assessing the influence of investment porosity on CSE.


Strengthening of porcelain by ion exchange subsequent to thermal tempering.

The purpose of this study was to test the hypothesis that high-leucite content feldspathic porcelain can be strengthened best by thermal tempering followed by ion exchange, compared with either thermal tempering or ion exchange alone. The results of biaxial flexure testing indicate that thermal tempering was the most effective way of strengthening the porcelain among the three methods tested. The combined procedure did not yield the greatest strengthening effect as hypothesized, but one that is only slightly stronger than that produced by ion exchange alone. Weibull analysis indicated that the ion-exchange treatment resulted in a narrower distribution of biaxial flexural strength compared with that of untreated or thermally tempered porcelain. The narrower distribution of biaxial flexural strength is considered desirable for enhancing the longevity of ceramic-based dental restorations.


The effect of cross-linking chain length on mechanical properties of a dough-molded poly(methylmethacrylate) resin.

Three different cross-linking agents which provide a range of cross-linking chain lengths and flexibilities were added to the monomer component of a dough-molded poly(methylmethacrylate) resin in various concentrations, and their effects on the impact strength, transverse bend strength, and tensile strength of the cured polymer were investigated. Increase in the chain lengths of cross-linking agents led to a decrease in the properties of transverse bend strength and tensile strength and an increase in the property of impact strength.


Bond strength of composite to porcelain treated with new porcelain repair agents.

In vitro tensile bond strengths of composite to porcelain were evaluated using three pretreatments (HF etching, sandblasting, diamond abrasion) of the porcelain, four bonding agents (Clearfil Porcelain Bond, Porcelain Liner M, Porcelain Liner M with Super-Bond C&B, and Scotchprime) and two storage conditions (24 h and thermocycling). The overall coefficient of variation was 27%. Significant differences among bond strengths were observed, with storage condition being the most important factor, followed by bonding agent and then pretreatment. Thermocycling decreased the bond strength of all samples, but samples treated with Scotchprime were affected least. For 24 h storage, Clearfil Porcelain Bond and Scotchprime had bond strengths above 23 MN/m2 to sandblasted porcelain.


Gamma-1 to beta-1 phase transformation in retrieved clinical amalgam restorations.

A number of important reactions occur in clinical amalgam restorations. This investigation examined the extent of the gamma-1 to beta-1 transformation in a variety of amalgam restorations retrieved from clinical trials. Sixteen restorations of five brands of low Cu amalgams, 28 restorations of four brands of high Cu blended amalgams, and eight restorations of three brands of high Cu single particle amalgams were studied. The extent of the gamma-1 to beta-1 transformation was determined by the ratio of the integrated intensity of the 002 beta-1 peak to the 330 gamma-1 peak in x-ray diffraction patterns. These values were correlated with age, marginal deterioration grade, and residual Hg content. Restorations consistently contained more beta-1 than comparable laboratory controls. Blended high Cu amalgams generally contained more beta-1, which was correlated with better marginal grades. Beta-1 content was inversely related to residual Hg content. No other associations could be established. A model of the complex interactions between corrosion and transformations was developed.


Frictional coefficients of ion-implanted alumina against ion-implanted beta-titanium in the low load, low velocity, single pass regime.

The frictional coefficients were measured for four wire alloys against the flats of polycrystalline alumina cylinders using a low load, low velocity, single pass device. Ion-implantations of titanium into polycrystalline alumina flats and nitrogen into beta-titanium wires reduced the static and kinetic coefficients from 0.50 and 0.44 before implantation to 0.20 and 0.25 after implantation, respectively. These results are similar in magnitude to frictional coefficients for unimplanted, control couples of stainless steel, cobalt-chromium, and nickel titanium wires against polycrystalline alumina flats. For orthodontic applications, we conclude that more efficient and reproducible appliances can be engineered for tooth movement if ion-implantation is used to reduce the abrasion of beta-titanium by polycrystalline alumina.


Effect of 4-MET on bond strength and penetration of monomers into enamel.

The effect of 4-[2-(methacryloyloxy)ethoxycarbonyl]phthalic acid (4-MET) in self-curing acrylic resin initiated by BPO-amine on the bond strength to etched enamel was studied. Scanning electron microscopic (SEM) observations of resin-enamel interfaces were carried out to elucidate the bonding mechanism and the effect of 4-MET on the adhesion. 4-MET, which has both hydrophilic and hydrophobic groups, increased the bond strength of self-curing acrylic resin to etched enamel and improved the bonding stability. SEM pictures strongly suggested that 4-MET promoted interpenetration of monomers into enamel prism peripheries and their polymerization therein resulted in excellent adhesion to etched enamel.


Quantitation of total mercury vapor released during dental procedures.

An in vitro method is described in which measurements were made of the total amount of mercury vapor released from three types of amalgam during routine dental procedures. It was found that the greatest amount of mercury was released during dry polishing of one amalgam (44 micrograms). Removal of amalgam from a Class I cavity under water spray and high volume evacuation also generated large amounts of mercury as expected (15-20 micrograms). However, under the more clinically relevant conditions of extending evacuation for one minute to remove residual amalgam and mercury after cutting, this value was reduced by approximately 90%. The total amount of mercury generated during placement (6-8 micrograms), wet polishing (2-4 micrograms) and trituration (1-2 micrograms) were also measured. The study showed that dental procedures associated with amalgam do potentially expose the patient and operator to mercury vapor. However, the total amount of mercury released during any procedure was far below the total exposure level calculated from the daily threshold limits established by regulatory agencies for occupational exposure.


The effect of thermocycling in microleakage analysis.

The purpose of this study was to evaluate the effect of thermocycling on dye penetration during in vitro microleakage analysis of composites. Fifty non-carious human molars, stored in 75% ethanol, were divided into five groups (N = 10). Each tooth was prepared for a MOD slot preparation using a high speed handpiece and water, one proximal cervical margin in cementum, the other in enamel. The enamel margins were etched, rinsed, dried, and the composite inserted and cured in multiple increments. Group A was not thermocycled (TC) and was immersed in 0.5% basic fuchsin dye for 24 h at 37 degrees +/- 1 degrees C. Group A' was not TC and was immersed in 0.5% basic fuchsin dye for 4 h at 37 degrees +/- 1 degree C. Group B was TC in a water bath and immersed in dye as with Group A, Group B' was TC and immersed in dye as in Group A'. Group C was TC, as in Group B, but in a basic fuchsin dye bath. Thermocycling consisted of 250 cycles, 15 s dwell time each in 5 degrees C and 50 degrees C bath. The teeth were mounted in acrylic, and multiple cross-sections of all surfaces were prepared. Dye penetration was read on a scale of 0 (no leakage) to 4 (leakage to the pulpal floor) and means calculated for each surface and tooth. There was no significant increase of microleakage in restorations when thermocycling was used to simulate temperature extremes, either in dye or water baths, as opposed to restorations which were not thermocycled.


Degradation of microfilled posterior composite.

The substantial improvement in the chemical, physical and mechanical characteristics of posterior composites has contributed to their increased use in recent years. However, some troubling characteristics of these materials are their susceptibility to wear, marginal leakage, and recurrent caries. Numerous studies have dealt with the wear resistance of posterior composites. Only a few have investigated the mechanisms of failure, particularly those containing submicron-sized fillers. The purpose of this study, therefore, was to analyze the clinical characteristics of a posterior composite to determine the mechanisms responsible for marginal degradation. Using a series of optical standards, it was determined that the generalized wear-rate was linear, averaging 8 microns/year. Furthermore, it was shown that the marginal defect was cohesive in nature and that this type of defect, which is inherent in submicron-type posterior composites, was probably due to tensile fatigue failure.


Effects of palladium addition on properties of dental amalgams.

Palladium-containing amalgam alloys were developed utilizing the atomization method. Single-compositional type alloys were fabricated and palladium was substituted for silver in concentrations up to 5 w/o. Alloy powder with a particle size of less than 45 microns was collected and triturated with mercury. Creep, compressive strength and dimensional change tests were performed according to ADA Specification No. 1 along with controls of Tytin, Valiant and Valiant-Ph.D. Values for creep decreased and compressive strength increased markedly with additions of palladium. Current densities of the experimental amalgams containing palladium were determined to be an order of magnitude less than the original amalgams in the electrochemical test. A trend of positive relationships between properties and palladium additions was indicated.


Treatment of composite surfaces for indirect bonding.

Composite can be cured extraorally to fabricate indirect or direct/indirect restorations. These restorations are bonded to the tooth with a dual-cure resin cement. This study evaluated various methods for treating the surface of an indirect glass-filled composite to improve its bond to enamel. The methods tested were air abrasion (sandblasting), hydrofluoric (HF) acid etching, silanation, and combinations of these techniques. Shear bond strengths were measured for thermocycled and non-thermocycled specimens. Air abrasion, followed by silanation, provided the strongest and most consistent bonds. Etching with 9.6% HF gel decreased the bond strengths obtained by air abrasion. HF alone produced the weakest bonds, with most failures occurring adhesively between the indirect composite and the resin cement.


The effect of glaze on porcelain strength.

The self-glazing technique provides an esthetic and hygienic surface for crowns and fixed partial dentures that use porcelain veneers. A study of the biaxial flexure strengths of polished vs. glazed specimens is needed to verify that current laboratory methods are appropriate for planned fatigue studies. Four groups of 50 porcelain disk specimens each were subjected to the following polishing and firing procedures: group one was fired, glazed-no hold, and polished; group two was fired, polished, and glazed-no hold; group three was fired, polished and glazed-1 min. hold; group four was fired, polished, and not glazed. The piston-on-three-ball method was used for testing biaxial flexure strengths. Significantly lower differences in biaxial flexure strengths were noted when group two values were compared with values from groups one, three and four. The results show that the Weibull distribution is an appropriate model for our studies. Differences in glaze thickness among the groups were noted in SEM examination; however, bulk (interior) microcrack density differences were absent. The specimens that were fired, polished to a 1 micron surface finish, and not glazed (group four) were significantly higher in flexure strength than groups one and three at the p less than 0.001 level. The hypothesis that glazing of porcelain surfaces improves the biaxial flexure strength of test specimens was rejected.


The plane of fracture and shear bond strength of three composite inlay systems.

Composite inlays have been introduced to overcome some of the problems encountered with direct placement techniques. However, some doubt has been expressed about the strength of the bond between the inlay surface and the composite luting cement due to the decreased number of C = C bonds remaining following supercuring of the inlay. This study investigated the bond strength of three composite inlay systems to etched bovine enamel and recorded the plane of fracture of the samples. The bond strength of one system was significantly greater than that of the other groups and was increased by the application of an unfilled resin enamel bonding agent. Unfilled resin application did not significantly alter the other systems tested. In only one of the systems tested was the inlay/composite cement bond found to be the weak link in the bonding procedure. In this group, the application of the manufacturer's specially formulated bond enhancer did not lead to an increase in bond strength.


Gastric fundic epithelial proliferation after pancreaticobiliary diversion. Studies with quantitative histological analysis and autoradiography in the hamster.

The effect of pancreaticobiliary diversion (PBD) with hypercholecystokininemia on the gastric fundic mucosa was studied in the Syrian golden hamster over 5 and 24 days. Sham-operated animals served as controls. Basal plasma gastrin concentrations were significantly decreased on days 5 and 24. Five days after PBD, there was a significant increase in the scintigraphically measured [3H]-thymidine incorporation into fundic tissue. Correspondingly, there was a significant increase in the number of cells with [3H]-thymidine-labeled DNA in the proliferative zone of the fundic mucosa. The total number of cells in the gastric pits, the number of cells in the proliferative zone and the proliferation index were also significantly increased 5 days after PBD. Although the mean values of all variables were higher after PBD than in the control group on day 24, these increases were not significant. It is concluded that PBD at least transiently stimulates gastric fundic epithelial proliferation in the hamster. Whether this is an effect of hypercholecystokininemia remains to be definitely proven in further studies.


The drug 5-aminosalicylic acid rescues alpha 1-proteinase inhibitor from the neutrophil oxidative inactivation. A possible contribution to its therapeutic action in ulcerative colitis.

The glycoprotein alpha 1-proteinase inhibitor is the specific inhibitor of neutrophil elastase, a major tissue-damaging protease. When incubated with activated neutrophils, alpha 1-proteinase inhibitor lost its pancreatic porcine elastase inhibitory capacity and became incapable of forming a sodium dodecyl sulphate-stable complex with pancreatic porcine elastase. Inhibitors and scavengers of neutrophil-derived reactive oxygen species outlined the crucial role of hypochlorous acid in the alpha 1-proteinase inhibitor inactivation. Moreover, the drug 5-aminosalicylic acid prevented the inactivation of alpha 1-proteinase inhibitor by neutrophils in a dose-dependent manner. Finally, when the capacity of 5-aminosalicylic acid to rescue alpha 1-proteinase inhibitor from the neutrophil-derived attack was plotted as a function of the 5-aminosalicylic acid ability to scavenge neutrophil-derived hypochlorous acid, a positive linear relationship was found. Thus, our results provide a direct evidence that 5-aminosalicylic acid is able to prevent the oxidative inactivation of alpha 1-proteinase inhibitor by neutrophils. Therefore, we suggest that the drug has the potential to limit the elastase-mediated damage of colonic connective tissue by creating a microenvironment of active alpha 1-proteinase inhibitor around the neutrophils.


Cell-kinetic alterations induced by aspirin in human gastric mucosa and their prevention by a cytoprotective agent.

The effect on gastric epithelial cell proliferation of a short-term, low-dose treatment with aspirin was evaluated in 9 healthy volunteers. Nine days before and during aspirin administration, the subjects assumed sulglycotide, a sulfated glycopeptide with cytoprotective properties. Endoscopic biopsies were collected in each subject from the gastric body and antrum before and after treatment. The specimens were incubated in a culture medium containing bromodeoxyuridine (BrdU). The proliferative activity was evaluated by immunohistochemical detection of BrdU uptake. A decrease in BrdU-labelled cells together with a shortening of the length of gastric columns were observed after treatment with aspirin and placebo in biopsies of both body and antrum (p less than 0.05). On the contrary, no modifications were observed after treatment with aspirin and sulglycotide. We conclude that a decrease in the proliferative activity of the epithelial cells could be one of the mechanisms by which aspirin affects the defensive properties of gastric mucosa. The treatment with a cytoprotective drug seems to be effective in preventing this alteration.


pH fluctuations versus reflux episodes in patients with gastroesophageal reflux disease: their optimal thresholds and significance in diagnosis.

In physiological and pathological conditions, pH monitoring in the esophagus shows small variations as well as more pronounced deflections. However, only the latter are traditionally taken into account in 24-hour pH monitoring analysis. The present study was designed to establish optimal thresholds of pH fluctuations versus reflux episodes in separating physiological and pathological gastroesophageal reflux (GER) and to evaluate their significance in the diagnosis. Twenty-four-hour intraesophageal pH monitoring and endoscopy were performed in 62 patients with GER symptoms and in 42 healthy controls. The results showed that the percentages of the time with pH fluctuations in patients with and without esophagitis and in healthy controls were, on average, 12.65, 9.5 and 2.76% in 24 h, respectively, and the respective percentages of the time with reflux episodes in the same groups in 24 h were, on average, 3.12, 2.04 and 0.18%, respectively. Using a receiver-operating-characteristic curve analysis, less than 6.7% of the time with pH fluctuations and less than 0.1% of the time with reflux episodes were defined as the combined thresholds for physiological versus pathological reflux. The sensitivity of the combined thresholds for the detection of GER patients with and without esophagitis was 96.7 and 90%, respectively, and their specificity for the diagnosis of patients with abnormal GER was 100%. It is concluded that pH fluctuations and reflux episodes, when evaluated together, are more useful for classifying patients with GER and their combined thresholds yield higher diagnostic accuracy in assessing patients with gastroesophageal disease.


Disability and need for rehabilitation among patients with inflammatory bowel disease.

Physicians who manage patients with inflammatory bowel disease (IBD) as well as the patients themselves need to know about the prospects of disability and the demand for rehabilitation associated with this chronic disease. The present study uses German social security statistics to characterize IBD patients undergoing a rehabilitation or having a disability and their employment status before and after rehabilitation. Each year, about 9 and 3% of all German employees with IBD underwent a rehabilitation or were granted a disability pension, respectively. In comparison with other diseases, IBD patients tended to be young, female and employed in white-collar occupations. Although they had significantly longer sick leaves, 87% were still employed before entering rehabilitation. The majority, i.e. 72%, improved under rehabilitation. Compared with other diseases, however, rehabilitation of patients with IBD was less successful, i.e. less patients improved, and more patients remained unchanged or even worsened during rehabilitation. After rehabilitation, continuation of the last employment was recommended in 82% of the cases, in 94% after additional medical or vocational measures. Overall, failed rehabilitation led to a similar rate of disability in IBD as in other diseases. Within the IBD population, however, female sex and white-collar occupations were associated with an increased risk, while male sex and blue-collar occupations were associated with a reduced risk for disability. These data reflect the underlying epidemiology of IBD as well as its natural history. Despite its severity and chronicity, the overwhelming majority of patients with IBD manage to stay in the work force and succeed in overcoming the obstacles posed by their disease.


Inhibitory effects of pravastatin, a competitive inhibitor of hydroxymethylglutaryl coenzyme A reductase, on cholesterol gallstone formation in prairie dogs.

The effects of pravastatin on cholesterol gallstone formation were determined in prairie dogs. We fed 10 prairie dogs 1% cholesterol with or without 0.05% (w/w) pravastatin (n = 5, each) for 4 weeks. In addition, another 5 prairie dogs were fed a standard rodent chow as a control. Only the animals fed 1% cholesterol without pravastatin treatment formed cholesterol gallstones. Gallbladder bile from cholesterol-fed animals contained cholesterol monohydrate crystals, whereas those treated with pravastatin contained no crystal. Furthermore, marked increases in tissue cholesterol levels (serum, liver and bile), and in biliary mucous glycoprotein levels were evident in cholesterol-fed animals, whereas pravastatin treatment normalized these levels. These findings raise the possibility that such inhibitors might have a future role to play in the prevention of cholesterol gallstone formation and/or recurrence.


Maternal insulin treatment improves pre-implantation embryo development in diabetic rats.

Pre-implantation embryos were recovered from control, diabetic and insulin-treated diabetic rats on day 5 of pregnancy. Compared to control animals, diabetic rats had a 20% reduction in the number of embryos per rat and blastocysts recovered from diabetic rats showed a 19% decrease in total cell number. The cellular decrease observed in blastocysts was mainly at the expense of the inner cell mass. Insulin replacement therapy was started on day 1 of pregnancy and normalized the glycaemia of diabetic rats but failed to raise the number of embryos per rat toward the control value. Insulin treatment, however, fully restored the normal cell number in both the inner cell mass and trophectoderm of blastocysts. The dead cell index, which was significantly elevated in the inner cell mass of blastocysts from diabetic rats, also returned to the control value following insulin treatment. Our data suggest that diabetes-induced impairment of pre-implantation development can be partly prevented by insulin treatment started shortly after conception.


Cytotoxic effects of cytokines on rat islets: evidence for involvement of free radicals and lipid peroxidation.

We have previously reported that oxygen free radical scavengers protect rat islet cells from damage by cytokines and we interpreted these findings as suggesting the involvement of oxygen free radicals but did not directly measure indices of free radical activity. In this study, we report on malondialdehyde, an end product of lipid peroxidation, in rat islets incubated with cytokines. The individual cytokines, interleukin 1 (1 U/ml), tumour necrosis factor (10(2) U/ml), and interferon gamma (10(2) U/ml) inhibited insulin release but did not increase islet malondialdehyde levels. Combination of these cytokines however, produced significant increases in islet malondialdehyde and this was accompanied by islet necrosis. Furthermore, an inhibitor of lipid peroxidation, U78518E, significantly decreased the cytokine-induced increase in islet malondialdehyde and protected islet Beta cells from destruction by the cytokine combination of interleukin 1, tumour necrosis factor and interferon gamma. These findings suggest that the cytotoxic action of cytokines on islet Beta cells may result from free radical production and lipid peroxidation in the islet cells.


Sorbinil does not prevent hyperfiltration, elevated ultrafiltration pressure and albuminuria in streptozotocin-diabetic rats.

The effects of aldose reductase inhibition on kidney function were studied in rats with streptozotocin-induced diabetes mellitus. Diabetic rats were fed sorbinil (20 and 50 mg/kg) by daily gastric gavage and were compared with untreated diabetic rats and normal rats. The rats were under daily supervision with regard to blood glucose control, insulin administration and body weight. The aim was to promote continuous body growth and to maintain the blood glucose concentration at around 22 mmol/l without large day-to-day fluctuations. The renal functional changes observed in this well-established diabetic model closely resembled those reported in human Type 1 (insulin-dependent) diabetes mellitus. Sorbinil treatment completely prevented renal cortical sorbital accumulation, but did not abolish kidney enlargement or the increase in ultrafiltration pressure and glomerular filtration rate. Albumin excretion was increased to the same extent in the sorbinil-treated and in the untreated diabetic rats. We conclude that increased metabolism of glucose to sorbitol does not cause the hyperfiltration in rats with streptozotocin-induced diabetes.


Genetic analysis of HLA class II alleles and susceptibility to type 1 (insulin-dependent) diabetes mellitus in Japanese subjects.

Although HLA-DQB1 alleles encoding aspartic acid at position 57 (Asp-57) are protective against Type 1 (insulin-dependent) diabetes mellitus in Caucasians, most Japanese Type 1 diabetic patients carry at least one Asp-57 DQB1 allele. We analysed the DRB1, DQA1 and DQB1 genes of 99 Japanese patients and 86 control subjects with polymerase chain reaction and sequence-specific oligonucleotide hybridization. We found that (1) the DQA1*0301 allele was significantly increased in Type 1 diabetic patients (RR7.8, pc less than 0.0001); (2) the DRB1*0405 (Dw15) allele, which is a subtype of DR4 haplotype, was significantly increased in DR4-positive patients (RR 12.0, pc less than 0.001); and (3) although the DRw8-DQw8 haplotype was positively associated with Type 1 diabetes, the DRB1*0406-DQw8 haplotype was decreased in the diabetic patients. These data indicate that DRB1 and DQA1 genes also confer susceptibility to Type 1 diabetes in Japanese.


Mechanical load on the inspiratory muscles during exercise hyperpnea in patients with type 1 (insulin-dependent) diabetes mellitus.

The aim of this study was to evaluate the difference between Type 1 (insulin-dependent) diabetic patients and healthy control subjects regarding inspiratory muscle load during exercise hypernea. For this purpose an incremental progressive exercise test on a cycle ergometer was performed by 36 Type 1 diabetic patients and 40 healthy subjects. In order to determine the mechanical load on the inspiratory muscles breath by breath, we selected the following two parameters, which represent the pressure generated by the inspiratory muscles as well as the duration and velocity of their contraction: (1) the oesophageal tension time index, which is the product of the duty cycle (ratio of inspiratory time to total breath cycle duration) and the mean oesophageal pressure expressed as a percentage of the maximal oesophageal pressure and (2) the mean oesophageal pressure change per time unit during the inspiratory phase of each breathing manoeuver, which is expressed as a fraction of the subject's maximal oesophageal pressure. Comparison of the two groups revealed that at similar levels of ventilation the mechanical load on the inspiratory muscles was significantly higher in the Type 1 diabetic patients than in the control subjects. When the loading was stopped the maximal ventilation was lower in the patients. Nevertheless, they reported a degree of respiratory effort sensation comparable to the control group, which seems to have been caused by an increase of the mechanical load on the ventilatory muscles.


Quality assessment of diabetes care according to the recommendations of the St. Vincent Declaration: a population-based study in a rural area of Austria.

Using a mobile ambulance the quality of diabetes care was evaluated, according to the recommendations of the St. Vincent Declaration, in 95% of all known diabetic patients (n = 395) in a geographically defined rural area of Austria with 7871 inhabitants. Fourteen of the 395 patients had Type 1 (insulin-dependent) diabetes with age at onset of diabetes below 30 years. Of the 375 patients examined (women 61%, age 66 +/- 13 years, median diabetes duration 6 years) 16% were treated with insulin and 47% with oral agents; HbA1c levels were 7.3 +/- 1.7%. Prevalence of known hypertension was 54%; 68% of these patients had their blood pressure uncontrolled (systolic greater than or equal to 160 and/or diastolic greater than or equal to 95 mmHg); a further 15% of patients with previously unknown hypertension had blood pressure values of greater than or equal to 160 and/or greater than or equal to 95 mmHg. Urinary albumin concentrations of greater than 200 mg/l were found in 15% of patients, 2% had a serum creatinine level of greater than 177 mumol/l, no patient had renal replacement therapy. Six patients (1.5%) were blind. Screening for retinopathy identified six patients (out of 317 in whom the retina could be evaluated) for whom consultation with an ophthalmologist as soon as possible was recommended. Of the total patient group (n = 395) 20 patients (5%) had foot complications (amputations and/or ulcers): 14 patients had a total of 21 lower limb amputations (eight above knee, six below knee, seven below ankle); eight of these 14 patients lived in a nursing home; 11 patients had a total of 13 foot ulcers.(ABSTRACT TRUNCATED AT 250 WORDS)


Enrichment of beta cells from the human fetal pancreas by fluorescence activated cell sorting with a new monoclonal antibody.

The aim of this study was to produce an antibody reactive to the surface of endocrine pancreatic cells and use this antibody for the purification of endocrine cells from the human fetal pancreas by fluorescence activated cell sorting. We describe such an antibody, called N1, reacting with the surface and cytoplasm of endocrine cells in the adult and fetal human pancreas (12 to 18 weeks gestational age). While unreactive to exocrine and mesenchymal cells, it was not specific for endocrine cells, as evidenced by its staining pattern in tissues other than pancreas. Almost 40% of the N1-positive pancreatic cells contained either insulin, glucagon or somatostatin. Conversely, more than 90% of each of the hormone-containing cells was N1 positive. An additional 40% of N1-positive cells, not containing other pancreatic hormones, was shown to contain islet amyloid polypeptide, synaptophysin, chromogranin, tyrosine hydroxylase or CA812. A two-step collagenase digestion protocol yielded 1.29 +/- 0.17 x 10(5) cells per mg pancreatic tissue. After Percoll gradient centrifugation, the suspension contained 15.6 +/- 5.7% (n = 25, mean +/- SD) cells reactive with N1. By fluorescence activated cell sorting using the antibody N1, the single-cell suspension was enriched from 3.0 +/- 1.4% to 16.2 +/- 4.8% (n = 10, p less than 0.01) Beta cells. Alpha and Delta cells were also enriched significantly by this procedure. The percentage of N1-positive cells increased from 17 +/- 4% to 83 +/- 6%. This preparation enriched for endocrine cells allows future studies on possible endocrine precursor cells.


The relation of fetal growth to plasma glucose in young men.

In a study of men aged 59 to 70 years plasma glucose levels 30 min and 2 h after a 75-g glucose load were inversely related to birthweight. To determine whether there are similar relations at a younger age the 30-min plasma glucose levels of 40 men aged 21 years, who were born in one hospital in the United Kingdom, were measured. Lower birthweight was associated with higher 30-min plasma glucose levels. This trend was independent of gestational age, and current body mass, height and social class.


Plasma lipoproteins and renal function during simvastatin treatment in diabetic nephropathy.

The aim of this study was to assess the effect of simvastatin on plasma lipoproteins and renal function in hypercholesterolaemic Type 1 (insulin-dependent) diabetic patients with diabetic nephropathy. Twenty-six hypercholesterolaemic (total cholesterol greater than or equal to 5.5 mmol/l) Type 1 diabetic patients with nephropathy were enrolled in a double-blind randomized placebo-controlled study for 12 weeks. The active treatment group (n = 14) received simvastatin (10-20 mg/day) for 12 weeks while the remaining 12 patients received treatment with placebo. The results during simvastatin treatment (baseline vs 12 weeks): total cholesterol 6.6 vs 4.8 mmol/l (p less than 0.01), LDL-cholesterol 4.25 vs 2.57 mmol/l (p less than 0.01) and apolipoprotein B 1.37 vs 1.06 mmol/l (p less than 0.01). HDL-cholesterol, and apolipoprotein A-I remained unchanged. Total cholesterol, LDL-cholesterol, HDL-cholesterol, apolipoprotein A-I, apolipoprotein B remained unchanged during placebo treatment. Albuminuria measured during the simvastatin and the placebo treatment (baseline vs 12 weeks) (the data are logarithmically transformed before analysis because of their positively skewed transformation; geometric mean (x/divided by antilog SE) is indicated) was 458 (x/divided by 1.58) vs 393 (x/divided by 1.61) and 481 (x/divided by 1.62) vs 368 (x/divided by 1.78 micrograms/min (NS). Glomerular filtration rate during simvastatin and placebo treatment (baseline vs 12 weeks) was 64 vs 63 and 72 vs 74 ml.min-1.1.73 m-2, respectively. Two patients receiving simvastatin treatment were withdrawn, one due to gastrointestinal side effects and one due to myalgia.(ABSTRACT TRUNCATED AT 250 WORDS)


Power spectral analysis of the electrocardiogram in diabetic children.

In recent years it has been shown that alteration in heart rate variability can be used for the objective assessment of autonomic function in adult diabetic patients. Using a microcomputer based system for on-line monitoring and analysis of heart rate variability by power spectral analysis, 100 children with Type 1 (insulin-dependent) diabetes mellitus were studied. A highly significant negative correlation was identified between heart rate variability and duration of diabetes (r = -0.88, p less than 0.0001). The mean heart rate variability in patients with diabetes of duration 3 years or more was significantly lower in comparison to age-matched control subjects. A highly significant negative correlation was evident between heart rate variability and mean HbA1 in patients with duration of diabetes of 5 years or more. A mean HbA1 over 10% during this period was associated with the greatest reduction in heart rate variability. Serial measurements of heart rate variability in diabetic children may be of predictive value prior to the onset of symptomatic neuropathy.


Body fat distribution and coronary heart disease mortality in subjects with impaired glucose tolerance or diabetes mellitus: the Paris Prospective Study, 15-year follow-up.

The Paris Prospective Study is a long-term, large-scale study of the factors predicting coronary heart disease in healthy middle-aged men. Subjects with impaired glucose tolerance or diabetes (not treated by insulin) at the first follow-up examination (n = 973) were selected from the total cohort for a separate analysis of the predictors of death from coronary heart disease. An index of body fat distribution, the iliac to thigh ratio, was entered into the list of potentially predictive variables, despite the fact that it had been measured one year before the first follow-up examination. After 15 years of mean follow-up, 41 of the selected subjects had died from coronary heart disease. Univariate analysis showed that these subjects differed from the subjects who died of another cause or who were alive at 15 years on the following variables: iliac to thigh ratio (p less than 0.0005), plasma triglyceride level (p less than 0.006), systolic blood pressure (p less than 0.01), and body mass index (p less than 0.04). In multivariate regression analysis using the Cox model, only iliac to thigh ratio and triglyceride plasma level achieved statistical significance as independent predictors. This result supports the current hypothesis that upper-body fat distribution, a characteristic trait of subjects with diabetes of glucose intolerance, plays an important role towards their high cardiovascular risk. However, it is unlikely that this role would be mediated through the lipid abnormalities that have been described as associated with upper-body fat deposition.


Insulin receptor and insulin-responsive glucose transporter (GLUT 4) mutations and polymorphisms in a Welsh type 2 (non-insulin-dependent) diabetic population.

We have recently examined the exons encoding the insulin receptor tyrosine kinase domain and GLUT 4 in 30 subjects with Type 2 (non-insulin-dependent) diabetes mellitus using a molecular scanning approach. The variant sequences Val-Met985 and Lys-Glu1068 of the insulin receptor and Val-Ile383 of GLUT 4 were each separately found in three different diabetic subjects. In a study of a Welsh population, the GLUT 4(383) variant was found in three of 160 diabetic and none of the 80 control subjects. In this study, the same group of Welsh Type 2 diabetic and control subjects was analysed using allele-specific oligonucleotide hybridisation, single nucleotide primer extension and allele-specific restriction digestion to ascertain the frequency of the two insulin receptor mutations. The Val-Met985 mutation was found in none of the 160 Welsh Caucasian Type 2 diabetic subjects and two of 80 control subjects. The Lys-Glu1068 mutation removes a Sty 1 site and digestion of amplified exon 18 with Sty 1 confirmed the presence of the mutation in the heterozygous state in the original subject. None of the Welsh diabetic or control subjects had the Glu1068 mutation. The discovery of a very common silent polymorphism at codon 130 of GLUT 4 allowed examination of the association of this locus with Type 2 diabetes using allele-specific oligonucleotide hybridisation in a subset of the Welsh subjects.(ABSTRACT TRUNCATED AT 250 WORDS)


Immunoradiometric assay of insulin, intact proinsulin and 32-33 split proinsulin and radioimmunoassay of insulin in diet-treated type 2 (non-insulin-dependent) diabetic subjects.

Plasma insulin, intact proinsulin and 32-33 split proinsulin measured by specific immunoradiometric assays and insulin and C-peptide measured by radioimmunoassay were measured during a constant infusion of glucose test in ten diet-treated subjects with a history of Type 2 (non-insulin-dependent) diabetes (termed diabetic subjects), mean fasting plasma glucose 6.0 +/- 1.0 mmol/l (mean +/- SD), and 12 non-diabetic control subjects. Immunoreactive insulin concentrations measured by radioimmunoassay were 33% higher than insulin and 16% higher than the sum of insulin and its precursors by immunoradiometric assay. The diabetic and non-diabetic subjects had similar fasting concentrations of insulin, intact proinsulin and 32-33 split proinsulin. The ratio of fasting intact proinsulin to total insulin was greater in the diabetic than the non-diabetic group 12.0% (6.8-21.0%, 1 SD range) and 6.3% (4.0-9.8%), respectively, p less than 0.01), though the groups overlapped substantially. After glucose infusion, diabetic and non-diabetic subjects had similar intact proinsulin concentrations (geometric mean 4.9 and 5.2 pmol/l, respectively), but the diabetic group had impaired insulin secretion by immunoradiometric assay (geometric means 55 and 101 pmol/l, p less than 0.05) or by radioimmunoassay C-peptide (geometric means 935 and 1410 pmol/l, p less than 0.05), though not by radioimmunoassay insulin (87 and 144 pmol/l, p = 0.12), respectively. Individual immunoradiometric assay insulin responses to glucose expressed in terms of obesity were subnormal in nine of ten diabetic subjects. Radioimmunoassay insulin and C-peptide gave less complete discrimination (subnormal responses in six of ten and eight of ten, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)