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Biomedical subjects

A Schantz

Publications and source records attributed to A Schantz.

At least 19 recordsLinked to original sources
PubMed2003

Consequences of immunogenicity to the therapeutic monoclonal antibodies ReoPro and Remicade.

The clinical consequences of immune antibodies generated to abciximab (ReoPro) and infliximab (Remicade) are described. Abciximab, a chimaeric Fab fragment that binds to the beta3 integrin of the GPIIb/IIIa and alphavbeta3 receptors on human platelets, is approved in the US and Europe for use in percutaneous coronary intervention (PCI) to prevent cardiac ischaemic complications. The effects of induced antibodies upon the safety and efficacy of repeat administration of abciximab have been evaluated in the ReoPro Re-administration Registry Study, in which 5.7% of patients were HACA positive before re-treatment. An interim evaluation of 1000 patients has indicated that re-administration of abciximab can be accomplished in the setting of PCI with an acceptable safety and efficacy profile. Infliximab is a chimaeric IgG1 antibody specific for human TNFalpha, and is approved in the US and Europe for the acute treatment of the signs and symptoms of Crohn's disease and for the chronic treatment of rheumatoid arthritis (RA). The incidence of antibodies to infliximab is reported to be approximately 10%; however, an inverse dose-immunogenicity relationship was observed, indicating that higher doses of infliximab (> or = 3 to 10 mg/kg) could reduce the incidence of immune antibodies. The induction of immune antibodies could also be reduced by concomitant administration of low-dose methotrexate and other immunosuppressant agents. Although antibodies to infliximab appeared to be associated with lower serum infliximab concentrations and a slightly higher incidence of infusion reactions, these immune antibodies were generally not associated with a reduction in clinical efficacy. In addition, the antibodies induced to infliximab are specific for infliximab, and do not cross-react with other currently available therapeutic antibodies.

Abciximab↗
PubMed2001

Abciximab readministration: results of the ReoPro Readministration Registry.

BACKGROUND: Platelet glycoprotein IIb/IIIa blockade with abciximab (ReoPro) improves the clinical outcomes of percutaneous coronary intervention. This registry was conducted to characterize the effects of repeated administration of abciximab during intervention. METHODS AND RESULTS: We recruited 500 consecutive patients at 22 centers in the United States who were receiving abciximab for at least a second time during percutaneous coronary intervention. Safety was measured as the incidence of hypersensitivity reactions, major bleeding, and thrombocytopenia. Efficacy was assessed as event-free clinical success. Human antichimeric antibody (HACA) responses were also characterized. There were no cases of hypersensitivity (95% upper confidence bound, 0.3%), major bleeding, or death. Clinical success was 94.4%. Thrombocytopenia occurred in 23 patients (4.6%; 95% CI, 2.8% to 6.4%), including 12 (2.4%; 95% CI, 1.1% to 3.7%) who developed profound thrombocytopenia (<20x10(9) cells/L). In 2 patients (0.4%), profound thrombocytopenia did not develop until after hospital discharge; in 4 (0.8%), profound thrombocytopenia recurred despite platelet transfusion. Before a first readministration, a positive HACA titer was present in 22 of 454 patients (4.8%); after a first readministration, an additional 82 of 432 (19.0%) became HACA-positive. HACA did not neutralize the in vitro inhibition of platelet aggregation by abciximab or correlate with clinical events. CONCLUSIONS: The results, including overall rates of thrombocytopenia, were consistent with randomized clinical trials of first abciximab treatment. However, there was a shift from mild to profound thrombocytopenia, and cases of delayed presentation and of recurrent thrombocytopenia were seen. These findings suggest that indications and guidelines for first-time use apply to retreatment, particularly the systematic monitoring for thrombocytopenia.

Abciximab↗
PubMed1999

Interruption of early pregnancy with mifepristone in combination with gemeprost.

BACKGROUND: Mifepristone in combination with prostaglandin has been used since 1988 for induction of early abortion. The aim of the present investigation was to assess the tolerance and efficacy of 600 mg. mifepristone orally followed by gemeprost 1 mg. vaginally either 24 hours (group one) or 48 hours (group two) later. METHODS: Sixty-four healthy women applying for abortion within the first 8 weeks of pregnancy were randomly allocated to one of the two treatment groups. Intrauterine pregnancy and gestational age were verified by ultrasonography. Symptoms after administration of mifepristone and gemeprost were recorded, and the patients observed at the hospital for at least three hours after prostaglandin-insertion. Blood samples for blood group, hemoglobin, beta-chorion-gonadotrophin, aspartate-aminotransferase and creatinine were drawn. RESULTS: Outcome was established by gynecological examination, the level of beta-hCG and ultrasonography, at visits one, two and if necessary three to four weeks later. Surgical curettage was performed in case of incomplete abortion, of which there were four in the 24-hour interval group and five in the 48-hour interval group with a success rate (complete abortion) of 55 out of 64 patients (86%). CONCLUSIONS: There was no difference in efficacy or side effects whether the prostaglandin was administered 24 or 48 hours after mifepristone intake, which suggests that the treatment period can be reduced from the conventional 48 hours.

Abdominal Pain↗
PubMed1997

Treatment with a chimeric CD4 monoclonal antibody is associated with a relative loss of CD4+/CD45RA+ cells in patients with rheumatoid arthritis.

This study investigates immunogenicity and in vivo effects on T-cells of long-term CD4 monoclonal antibody treatment of patients with rheumatoid arthritis. Patients were treated with several dosage regimens of a chimeric CD4 monoclonal antibody entitled cM-T412 over the course of 1 year. The circulating CD4+ T-cell count sharply decreased after the first cM-T412 injection and slowly recovered after the last injection. Within the CD4+ subset there was a selective depletion of CD45RA+ T cells, HLA-DR+, and CD25+ cells, providing evidence that activated/memory CD4+ cells resist the effect of CD4 monoclonal antibodies. Studies on cytokine production by peripheral blood mononuclear cells cultures in vitro revealed no differential effect on the production of interleukin-4 compared to interferon-gamma, indicating that a shift from a Th1 to a Th2 lymphokine production profile was not achieved. Human anti-monoclonal antibodies (HAMA) were induced in a minority of the patients predominantly after the first treatment course. All the sera containing HAMA specifically inhibited the binding of cM-T412 to T-cells. However, HAMA formation does not interfere with the biological effect of repeated cM-T412 administration since the degree of CD4 depletion following repeated administration of cM-T412 to patients with and without blocking antibodies was similar. We conclude that the currently available data are of critical importance in the interpretation of the obtained clinical experience and for further development of this therapeutic strategy.

Adult↗
PubMed1996

Percentage of anti-CD4 monoclonal antibody-coated lymphocytes in the rheumatoid joint is associated with clinical improvement. Implications for the development of immunotherapeutic dosing regimens.

OBJECTIVE: We assessed the effect of a daily dosing schedule of the chimeric anti-CD4 monoclonal antibody (MAb), cM-T412, in rheumatoid arthritis (RA) patients, and compared lymphocyte changes in the peripheral blood (PB) and synovial fluid (SF) of these patients. METHODS: Twelve patients received 50 mg/day of cM-T412 for 5 days, followed by a maintenance treatment of 50 mg/week for 5 weeks (6 patients), or a retreatment course of 50 mg/day for 5 days after 5 weeks (6 patients). Paired PB and SF samples were obtained during treatment for analysis. RESULTS: Changes in lymphocyte count and coating with the MAb in PB did not reflect changes in the SF. After 5 daily treatments, the percentage of cM-T412-coated CD4+ lymphocytes in SF correlated with the degree of clinical improvement seen in patients at 2 weeks after the initiation of therapy (r = 0.75, P < 0.05). CONCLUSION: These results demonstrate the importance of antibody dosage and treatment regimen in determining clinical benefit. Our findings suggest that the percentage of cM-T412-coated CD4+ lymphocytes in SF may be a predictor of clinical outcome.

Adult↗
PubMed1990

Identification of a common enterobacterial flagellin epitope with a monoclonal antibody.

A monoclonal antibody (mAb), designated 15D8, was produced from BALB/c splenocytes of mice injected with Escherichia coli flagella. ELISA of motile cells, non-motile cells and partially purified flagellin proteins showed that the mAb reacted specifically with flagella of E. coli and with other members of the family Enterobacteriaceae. Western immunoblot analyses of enterobacterial flagella or cell extracts demonstrated that the antibody reacted with a single protein species in the extracts which was identical in size to purified flagellin. The antigenic determinant for this antibody appears to be surface exposed and linear in configuration, since the antibody reacted with native flagella and flagella which had been denatured. This antibody was also used to demonstrate that although the flagella proteins are heterogeneous in size, at least one epitope is highly conserved.

Antibodies, Monoclonal↗
PubMed1989

Prediction of ovulation.

The purpose of this investigation was to evaluate all available ovulatory diagnostics with respect to sensitivity, specificity, diagnostic specificity (predictive value of a positive test, PVP) and diagnostic sensitivity (predictive value of a negative test, PVN). Twenty-one ovulatory women with more than 3 years of infertility problems were included in the study. PVP and PVN were highest for detection of urinary luteinizing hormone (LH) peak at ovulation (PVP = 90%, PVN = 95%) and for serum-estradiol peak 1 day before ovulation (PVP = 83%, PVN = 97%). The predictive values were lower for all other tests. The PVP (54%) and PVN (90%) were rather low for detection of ovulation with vaginal electric impedance. However, all ovulations were predicted when urinary LH peak and vaginal impedance were combined. Two women were stimulated with human chorionic gonadotropin to investigate a possible connection between the LH peak and the preovulatory vaginal electric impedance. No close connection between them could be demonstrated. Basal body temperature should not be used for the prediction of ovulation (PVP = 25%). We suggest that ovulation should primarily be predicted from the identification of the urinary LH peak and that other methods be supplementary.

Analysis of Variance↗
PubMed1987

Warm tub bath during delivery.

In a prospective study, 88 women bathed in a warm tub bath for 1/2-2 hours during first stage labor after a strictly normal pregnancy, ending with spontaneous onset of labor at term. A control group consisted of 72 women fulfilling the same criteria of normality during pregnancy and labor, but who did not want to take a warm tub bath during labor. Apart from the bath, the two groups followed the usual obstetric procedures of the Department. The cervical dilatation in the "bath group" was 2 1/2 cm/h compared with 1 1/4 cm/h in the "control group". Mean pain score in the bath group was higher at the start of the study, before the bath, and they experienced a pain relief during bath which was not observed in the control group. This difference may be due to bias. The use of morfica and the need for stimulation of labor contractions were both twice as high in the control group, but this difference was not significant. No differences were observed with regard to operative delivery, vaginal or perineal laceration or in bleeding during labor or postpartum. The total duration of labor was the same in the two groups and no differences in neonatal condition were observed. The bacterial contamination of the bath water was insignificant and there were no significant febrile episodes post partum.

Adult↗
PubMed1987

Outpatient treatment of cervical intra-epithelial neoplasia. The CO2 laser versus cryotherapy, a randomized trial.

In a randomized study, 204 patients were allocated to either laser or cryo treatment for cervical intra-epithelial neoplasia (CIN). The patients were treated on an outpatient basis without anesthesia unless other conditions requiring anesthesia had to be dealt with at the same time. Both the laser and the cryo method were highly acceptable to the patients. Slightly more patients experienced moderate or severe pain during laser treatment, compared with cryo treatment (P = 0.05). Peroperative hemorrhage did not exceed 25 cc except for one laser-treated patient. Postoperative vaginal discharge was more often seen after cryo coagulation, the discharge being malodorous in 36% of cryo-treated patients and in 17% of laser-treated patients. Pelvic inflammatory disease was found in one patient in each treatment group. Postoperative spotting occurred more often in laser-treated patients (49%) than in cryo-treated patients (22%). At follow-up colposcopy 3 months after treatment, the squamocolumnar junction was fully visible significantly more often in laser-treated patients (P less than 0.001). The cure rates after one laser or cryo treatment were 90% and 91%, respectively. Subsequent to 19 initial treatment failures, 8 patients have at present been retreated with the same method as initially used, and all 8 are cured. The cure rates after one or two treatments are 96% in the laser group and 93% in the cryo group. The rates are preliminary, due to the short observation time. Publications will appear when all patients have been followed for 2 and 5 years.

Adult↗
PubMed1984

Cryosurgery for dysplasia of the uterine ectocervix. A randomized study of the efficacy of the single- and double-freeze techniques.

This prospective, randomized study of 142 women with mild or moderate dysplasia of the uterine ectocervix shows that the double-freeze technique is significantly more effective than the single-freeze technique, the recurrence rates being, respectively, 6.2% and 16.3%. The highest recurrence rate was found in the group treated with a single freeze and having the most extensive portio involvement. All patients were examined colposcopically before cryosurgery in order to exclude patients with lesions extending into the cervical canal and in order to evaluate the size of the lesion. Recurrent lesions were usually diagnosed within the first year (75%) and in only one patient more than 2 years after treatment. None of the patients developed invasive cancer. The mean follow-up period was 27 months (24-42 months). We consider cryosurgery to be an acceptable treatment for selected patients. Our criteria for entry were mild or moderate dysplasia of the uterine ectocervix, and colposcopic visualization of the entire transformation zone to ensure that the lesion does not extend into the cervical canal. Our experience from the present study is that the following criteria should be added: the portio involvement must not be too extensive and the patient must agree to follow-up examination. When these conditions are fulfilled, future treatment in our department will consist of a double freeze extending 3 mm beyond the lesion, with a thaw interval of 4 min.

Adolescent↗
PubMed1980

A minor complication of cryosurgery--occlusion of the cervical canal.

In a series of 145 patients who underwent cryosurgery of the cervix uteri, six cases (4 per cent) were found with occlusion of the cervical canal. The patients complained of constant pains resembling labor. Inspection of the cervix uteri showed necrosis covering the orificium externum uteri. On removal of the necrotic area there was a discharge of watery fluid. The patients were then free of pain.

Adult↗
PubMed1976

Parathyroid hyperplasia in primary hyperparathyroidism: a review of 85 cases.

Parathyroid hyperplasia of all four glands was found to be the cause of primary hyperparathyroidism in 85 of 557 cases seen at the Massachusetts General Hospital between 1930 and 1973. There were 66 cases of chief cell hyperplasia and 19 cases of clear cell hyperplasia that were grossly, microscopically, and ultrastructurally distinct. Although the clinical findings overlap, there are several differences in the signs and symptoms between these two forms of hyperplasia. Both types are treated by subtotal removal of all the parathyroid tissue. Removal of insufficient tissue has left residual hyperparathyroidism in 45% of those with chief cell hyperplasia and 11% of those with clear cell hyperplasia after what was thought to be definitive surgery. Postoperative hypoparathyroidism was found in 15% of the patients with chief cell hyperplasia and in none with clear cell hyperplasia. These findings further suggest that removal of three and one-half glands in the more than 86% of patients with one gland involvement (adenoma or carcinoma) as the cause of primary hyperparathyroidism is unwarranted.

Adult↗
PubMed1976

Testicular microlithiasis with sterility.

A case report of male infertility associated with testicular microlithiasis is presented. This rare condition has not previously been associated with infertility. A variable maturation arrest was observed in the spermatogenic epithelium. The question of whether the microliths are the cause of the infertility or whether both conditions are the result of some unknown agent must await further elucidation.

Adult↗