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Biomedical subjects

M Schachter

Publications and source records attributed to M Schachter.

At least 19 recordsLinked to original sources
PubMed2006

Morphology assessment and fluorescence in situ hybridization of the same spermatozoon using a computerized cell-scanning system.

BACKGROUND: Poor sperm morphology is statistically associated with an increase in the incidence of chromosome abnormalities. Our aim was to examine the possible correlation between chromosomal aberrations and sperm morphology in the same cell. METHODS: 12349 spermatozoa from 7 teratozoospermic and one globozoospermic patients, and from 3 fertile donors were analyzed using a system which scans for cell morphology and chromosomal ploidy in the same cell using digital technology. RESULTS: Chromosomal aberrations were detected in 5.3% of teratozoospermic cases and in 6.7% in the globozoospermic patient compared with 1.6% in donors (P < 0.0001). Chromosomal aberrations were more common in abnormally formed sperm compared with normal spermatozoa: 4.5% vs 1.3% in the teratozoospermic group and 2.0% vs 0.3% in the control group (NS), especially frequent among sperm with two heads or two tails (52.1-77.2%) or extreme head deformations (10.6-11.1%) irrespective of grouping, and in mild amorphous heads in the globozoospermic patients (20.2%). The frequency of chromosomal aberrations in morphologically normal sperm was comparable whether derived from teratozoospermic or normospermic patients. CONCLUSIONS: The computerized cell-scanning system demonstrated the relationship between chromosomal aberrations and sperm morphology in the same spermatozoon. The incidence of chromosomal aberrations was positively linked to abnormal sperm morphology, the more severe the abnormality, the higher the incidence of aneuploidy.

Aneuploidy↗
PubMed2005

Meiotic arrest in vitro by phosphodiesterase 3-inhibitor enhances maturation capacity of human oocytes and allows subsequent embryonic development.

Controlling nuclear maturation during oocyte culture might improve nuclear-cytoplasmic maturation synchrony. We aimed to evaluate the quality of in vitro-matured, germinal vesicle (GV)-stage human oocytes following a prematuration culture (PMC) with a meiotic arrester, phosphodiesterase 3-inhibitor (PDE3-I). Follicles (diameter, 6-12 mm) were retrieved 34-36 h post-hCG administration from informed, consenting patients who had undergone controlled ovarian stimulation. Cumulus-enclosed oocytes (CEOs) presenting moderate expansion or full compaction were placed in PMC with the PDE3-I, Org9935, for 24 or 48 h. Subsequently, oocytes were removed from PMC, denuded of cumulus cells, matured in vitro, and fertilized, and the resulting embryos were cultured. In the presence of PDE3-I, approximately 98% of the oocytes were arrested at the GV stage. Following PDE3-I removal, oocytes acquired a higher maturation rate than oocytes that were immediately denuded of cumulus cells after retrieval and in vitro matured (67% vs. 46%, P = 0.01). In controls, immature CEOs retrieved with moderate expansion reached higher maturation rates compared to fully compacted CEOs, but in PMC groups, high values of maturation were achieved for both morphological classes of CEOs. No effect of PMC on fertilization was observed. A 24-h PMC period proved to be the most effective in preserving embryonic integrity. Similar proportions of nuclear abnormalities were observed in embryos of all in vitro groups. In summary, PMC with the specific PDE3-I had a beneficial effect on human CEOs by enhancing maturation, benefiting mainly the fully compacted CEOs. This resulted in an increased yield of mature oocytes available for insemination without compromising embryonic development. These results suggest that applying an inhibitor to control the rate of nuclear maturity by regulating intraoocyte PDE3 activity may allow the synchronization of nuclear and ooplasmic maturation.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2005

The use of ezetimibe in achieving low density lipoprotein lowering goals in clinical practice: position statement of a United Kingdom consensus panel.

There is no doubt that lowering serum cholesterol levels reduces the risk of major coronary events. This evidence has led treatment guidelines to set progressively lower targets for low density lipoprotein cholesterol (LDL-C). However, despite widespread use of statins, substantial numbers of patients do not achieve the LDL-C goals. Using higher doses of statins in an attempt to achieve these targets may increase the risk of serious adverse effects. Furthermore, the use of combination therapy with agents such as bile acid sequestrants, niacin and fibrates has been limited by increased potential for side effects, drug interactions and poor compliance. Ezetimibe, a selective cholesterol transport inhibitor, reduces the intestinal uptake of cholesterol without affecting absorption of triglycerides or fat-soluble vitamins. In clinical studies, ezetimibe 10 mg, in combination with statins or as monotherapy, was well tolerated and reduced LDL-C by 34-53% and 17-18%, respectively. The available evidence for ezetimibe is reviewed. The role of ezetimibe in increasing the proportion of patients attaining LDL-C treatment goals is discussed.

Anticholesteremic Agents↗
PubMed2004

The outcome of ICSI of immature MI oocytes and rescued in vitro matured MII oocytes.

BACKGROUND: The use of immature oocytes is limited to cases where these are the only available oocytes, and they are usually only microinjected with sperm after having undergone maturation in vitro. This study compares the outcome of injection of sperm into metaphase I oocytes immediately after their denudation (MI) performed 2 h after their retrieval, with the outcome of injection of sperm into rescued in vitro matured metaphase II (IVM MII) oocytes after their short incubation in routine laboratory conditions. METHODS: ICSI was performed on MI oocytes, rescued IVM MII oocytes and on MI oocytes that were incubated but failed to extrude their first polar body (arrested IVM MI). Fertilization and cleavage rates were compared with those achieved in mature metaphase II oocytes (MII). RESULTS: ICSI of MI oocytes showed impaired performance compared with ICSI of rescued IVM MII oocytes and MII oocytes, in terms of oocyte degeneration rate (11 versus 6 versus 4%; P < 0.0001), fertilization rate (28 versus 44 versus 68%; P < 0.0001) and multipronucleated fertilization (10 versus 4 versus 4%; P < 0.01). The cleavage rate was lower in rescued IVM MII oocytes compared with MII oocytes (86 versus 95%; P < 0.01). Arrested IVM MI oocytes showed similar results to those of MI oocytes but had a lower cleavage rate (72 versus 96%; P < 0.01). CONCLUSIONS: The injection of rescued IVM MII oocytes is preferred to the injection of MI oocytes.

Adult↗
PubMed2003

Coasting-what is the best formula?

Coasting is a method to decrease the incidence of ovarian hyperstimulation syndrome (OHSS), which involves withdrawing exogenous gonadotrophins until the serum estradiol (E(2)) level decreases. The application of this strategy, as it appears in the literature, has been variable, with heterogeneous criteria for initiating and ending the coasting process and as a result, reports of efficacy are inconsistent. In attempt to establish a recommended protocol for coasting we reviewed and analysed 10 relevant studies, found by a Medline search. Based on the data collected, coasting should be initiated when the serum E(2) concentration exceeds 3000 pg/ml, but not unless the leading follicles reach a diameter of 15-18 mm. Its duration should be limited to <4 days, thus, preventing the decrease in implantation and pregnancy rates that occur after longer periods of coasting. Administration of hCG should be withheld until serum E(2) falls below 3000 pg/ml. Based on the published data, these suggested guidelines result in an acceptably low incidence of severe OHSS (<2%) and provide satisfactory fertilization and pregnancy rates (55-71% and 36.5-63% respectively). A multicentre randomized prospective study would help to confirm the effectiveness of this approach.

Chorionic Gonadotropin↗
PubMed2002

Rates of cholesterol esterification and esterified cholesterol net mass transfer between high-density lipoproteins and apolipoprotein B-containing lipoproteins in Type 1 diabetes.

AIMS: Type 1 diabetes is associated with a high incidence of coronary heart disease (CHD) despite paradoxically normal or high high-density lipoprotein (HDL) cholesterol concentrations. Triglyceride (TG) concentrations have been shown to be important determinants of two aspects of HDL metabolism: cholesterol esterification rate and esterified cholesterol (EC) net mass transfer rate between HDL and the apolipoprotein B-containing lipoproteins. In order to try to explain the paradox, we aimed to assess the relationships between plasma TG and these two processes in Type 1 diabetic compared with non-diabetic subjects. METHODS: Rates of cholesterol esterification and EC net mass transfer between HDL and the apolipoprotein B-containing lipoproteins were assessed by incubating whole plasma at 37 degrees C; intra-assay coefficients of variation were 6% and 30%, respectively. RESULTS: Ten Type 1 diabetic and 10 non-diabetic subjects, with similar ages, sex distributions, body mass indices and total cholesterol and TG concentrations, were assessed. Apolipoprotein A1, HDL unesterified cholesterol, and HDL phospholipid concentrations were greater in the Type 1 diabetic subjects. There were no significant differences in the rates of cholesterol esterification or EC net mass transfer between the groups. There were strong associations between plasma TG and the rate of cholesterol esterification and between plasma TG and the rate of EC net mass transfer in Type 1 diabetic subjects (r = 0.83, P = 0.0027 and r = 0.88, P = 0.0009, respectively) and in non-diabetic subjects (r = 0.91, P = 0.0002 and r = 0.79, P = 0.0070, respectively). However, the slopes of the associations with plasma TG were significantly steeper in the Type 1 diabetic subjects (analyses of covariance P = 0.0053 and P = 0.0146, respectively). CONCLUSIONS: Increases in TG may therefore promote more EC enrichment of atherogenic apolipoprotein B-containing lipoproteins in Type 1 diabetes while also promoting more cholesterol esterification, thereby maintaining HDL cholesterol concentrations. This could contribute to the paradox of high CHD incidence despite normal or high HDL cholesterol concentrations in Type 1 diabetes.

Adult↗
PubMed2002

Factors influencing the outcome of ICSI in patients with obstructive and non-obstructive azoospermia: a comparative study.

BACKGROUND: Factors influencing success of sperm retrieval in azoospermic patients and outcome of ICSI were evaluated. METHODS AND RESULTS: Uni- and multifactorial analysis were performed using logistic and stepwise analysis, following surgical sperm retrieval by percutaneous epididymal sperm aspiration (55 cycles) or testicular sperm extraction (142 cycles) in 52 and 123 patients with obstructive azoospermia (OA) and non-obstructive azoospermia (NOA) respectively. ICSI cycles using fresh or cryopreserved-thawed sperm were included. Sperm were retrieved to allow ICSI in 100 and 41% of OA and NOA patients, with no significant correlation with patients' age or FSH level. Occurrence of pregnancy was significantly correlated with female age (90th quantile: 38 years), number of oocytes retrieved (10th quantile: five oocytes) and number of oocytes injected (10th quantile: four oocytes). Sperm origin (epididymal versus testicular), status (fresh or thawed), male partner's age, and serum FSH had no significant effect upon implantation rate, pregnancy rate per embryo transfer or spontaneous miscarriage rate. CONCLUSIONS: In OA patients ICSI should be planned in conjunction with surgical sperm retrieval. In contrast, the lack of efficient non-invasive parameters to predict sperm retrieval in NOA suggests that elective surgical sperm retrieval may be offered to these patients prior to ovarian stimulation of their partners, especially when donor back-up is not an alternative. Female factors such as age and ovarian reserve have significant impact upon clinical success rates.

Adult↗
PubMed2002

Outcome of first and repeated testicular sperm extraction and ICSI in patients with non-obstructive azoospermia.

BACKGROUND: It is unclear whether or not testicular sperm extraction (TESE) should be repeated for patients in whom no sperm were found during their first TESE attempt. METHODS AND RESULTS: The outcome of repeated TESE was evaluated in patients with non-obstructive azoospermia (NOA) after failing to obtain sperm in their first extraction attempt, or having used all available cryopreserved testicular tissue. Out of 83 patients with NOA, patients repeated TESE two (n = 22), three (n = 8), four (n = 6) and five (n = 3) times. Distribution of main testicular histology included germ cell aplasia (55%), maturation arrest (29%) and germ cell hypoplasia (16%). The first TESE yielded mature sperm for ICSI in 39% of patients (sp+), and failed in the remaining 61% (sp-). A second TESE yielded mature sperm in 1/4 from the sp- group and in 16/18 from the sp+ group. At the third, fourth and fifth trials, 8/8, 5/6 and 3/3 of the original sp+ patients were sp+ again respectively. Compared with the outcome of the first trial, all further trials did not differ statistically in the rate of fertilization (54 versus 49%), implantation (9.5 versus 5.4%), or clinical pregnancy/cycle (19 versus 15%). No pregnancies were achieved among the three patients after their fifth TESE. Pregnancies occurred in all histological groups, except maturation arrest. CONCLUSIONS: The outcome of repeated TESE cycles, up to the fourth trial, justifies the procedure.

Adult↗
PubMed2002

Prescribing errors in hospital inpatients: their incidence and clinical significance.

BACKGROUND: It has been estimated that 1-2% of US inpatients are harmed by medication errors, the majority of which are errors in prescribing. The UK Department of Health has recommended that serious errors in the use of prescribed drugs should be reduced by 40% by 2005; however, little is known about the current incidence of prescribing errors in the UK. This pilot study sought to investigate their incidence in one UK hospital. METHODS: Pharmacists prospectively recorded details of all prescribing errors identified in non-obstetric inpatients during a 4 week period. The number of medication orders written was estimated from a 1 in 5 sample of inpatients. Potential clinical significance was assessed by a pharmacist and a clinical pharmacologist. RESULTS: About 36200 medication orders were written during the study period, and a prescribing error was identified in 1.5% (95% confidence interval (CI) 1.4 to 1.6). A potentially serious error occurred in 0.4% (95% CI 0.3 to 0.5). Most of the errors (54%) were associated with choice of dose. Error rates were significantly different for different stages of patient stay (p<0.0001) with a higher error rate for medication orders written during the inpatient stay than for those written on admission or discharge. While the majority of all errors (61%) originated in medication order writing, most serious errors (58%) originated in the prescribing decision. CONCLUSIONS: There were about 135 prescribing errors identified each week, of which 34 were potentially serious. Knowing where and when errors are most likely to occur will be helpful in designing initiatives to reduce them. The methods developed could be used to evaluate such initiatives.

Delphi Technique↗
PubMed2001

A spontaneous canine model of mucous membrane (cicatricial) pemphigoid, an autoimmune blistering disease affecting mucosae and mucocutaneous junctions.

Mucous membrane pemphigoid (MMP) is a rare autoimmune blistering dermatosis of humans that was previously known as cicatricial pemphigoid. It is characterized by vesicles, ulcers and scarring that affect predominantly mucosae and mucocutaneous junctions. Circulating autoantibodies recognize epitopes on basement membrane proteins such as collagen XVII or laminin-5/6. Herein, we describe the clinico-pathological and immunological characteristics of 17 dogs afflicted with a dermatosis homologous to MMP of humans. Patients exhibited vesicles and erosions predominantly on mucous membranes or mucocutaneous junctions of the mouth, nose, eyes, genitalia or anus. Histopathology revealed subepithelial vesicles with variable dermal inflammation. Direct immunofluorescence demonstrated IgG or complement at the dermoepithelial junction. Indirect immunofluorescence using salt-split epithelia permitted the detection of circulating basement membrane-specific IgG autoantibodies in 15 cases. In 11 patients, autoantibodies recognized the NC16A segment of collagen XVII, as determined by salt-split indirect immunofluorescence, immunoblotting using canine keratinocytes and ELISA with synthetic canine peptides. In one dog, autoantiodies bound to the dermal side of salt-split epithelia and recognized epitopes within the 30 kDa carboxy-terminal segment of human collagen XVII. Canine MMP, like its human counterpart, exhibits distinctive clinical signs and histopathological lesions, yet circulating autoantibodies target different antigenic epitopes. This spontaneous canine model of MMP could prove useful for studies on the pathogenesis or therapy of this human disease.

Animals↗
PubMed2001

Factors associated with continued participation in mammography screening.

BACKGROUND: Relatively little is known about factors that predict ongoing participation in mammography screening at regular intervals. Members of managed care plans have access to this preventive service; yet, many still do not receive it routinely. METHODS: Using administrative data from HIP Health Plan of New York, a group model HMO, 24,215 women ages 50-80 years identified as having a screening mammogram during the baseline period were followed for 2 years to determine demographic and utilization factors that might be related to having a subsequent mammogram within the recommended time interval. RESULTS: Of the 24,215 women with an index mammogram, 71.8;pc had a subsequent screening mammogram within 2 years. Women ages 65-74 years and those with Medicare coverage had the highest mammogram rates among the age and coverage categories. Number of primary care and gynecology physician visits was strongly related to having a subsequent mammogram. The average (mean) time between index and subsequent mammogram was 14.4 months. CONCLUSION: The significance of health plan visits in subsequent mammography underscores the importance of physician-patient communication in a managed care plan and the integration of health plan members into the HMO delivery system. Even in this environment with equal access for all types of coverage, Medicaid members were less likely to receive this preventive service.

Aged↗
PubMed2001

Influence of a short or long abstinence period on semen parameters in the ejaculate of patients with nonobstructive azoospermia.

OBJECTIVE: To compare the effect of a short (4 days) or a long (14 days) abstinence period on sperm retrieval by extended sperm preparation in patients with nonobstructive azoospermia scheduled for testicular biopsy and intracytoplasmic sperm injection (ICSI). DESIGN: A prospective case control study. SETTING: Male infertility clinic in a university hospital. PATIENT(S): Fifty male patients with nonobstructive azoospermia, scheduled for testicular biopsy for ICSI. INTERVENTION(S): Diagnosis of nonobstructive azoospermia and a thorough microscopic search for sperm cells (extended sperm preparation). MAIN OUTCOME MEASURE(S): The number of sperm cells collected, sperm motility, and total motile sperm count after short and long abstinence periods. RESULT(S): There was a significant difference between long and short abstinence with an increase in sperm count (log-to-log transformed analysis of variance P<.025) and total motile sperm (P<.025 analysis of variance, P<.02 paired Student's t-test) in the former group, but no significant change in sperm motility (Wilcoxon and paired Student's t-test). In 18 patients, sperm concentration and sperm motility were similar in a second collection, done after the same abstinence period, compared with the same parameters in the first sample. When at least 10 motile sperm were defined as the cutoff number, allowing ICSI without testicular biopsy, no significant differences were found between the two abstinence periods. No clinical or laboratory male characteristic could predict the detection of 10 motile sperm by extended sperm preparation either after a short or a long abstinence period. CONCLUSION(S): Sperm count and total motile sperm were increased after a long abstinence period, with no change in sperm motility. No additional advantages were conferred by long abstinence as opposed to short abstinence when 10 motile sperm were defined as the cutoff number for ICSI. The recommended period of abstinence for extended sperm preparation and ICSI, whether short or long, should be individualized for each patient.

Adult↗
PubMed2001

Improvement of IVF outcome in poor responders by discontinuation of GnRH analogue during the gonadotropin stimulation phase--a function of improved embryo quality.

PURPOSE: To assess the efficacy of a protocol involving the discontinuation of the GnRH analogue at the mid-phase of ovarian stimulation for IVF in patients with a previous poor response. METHODS: Prospective case-control evaluation compared with same patient's previous performance. Thirty-six patients enrolled in an IVF program were treated in two consecutive cycles. The first with a standardized protocol utilizing midluteal administration of Nafarelin (N) 600 mcg/d continued throughout the stimulation phase with human menopausal gonadotropin (hMG) until follicles of 20 mm were identified by transvaginal ultrasound (Standard group). Patients with a poor response in the Standard cycle were treated in the subsequent cycle with N and hMG initially in a similar manner, then N was stopped after 5 days of hMG stimulation (N-stop group). All clinical and laboratory aspects of treatment were done in a similar fashion in both cycles, each patient acting as her own control. RESULTS: Results were analyzed by paired t test. The change in each parameter in the N-stop cycle was expressed as the percent change as compared with the standard protocol cycle for each patient. Peak estradiol (E2) and number of aspirated oocytes were increased in the N-stop cycle (+16.9% and +28%, respectively), but insignificantly so. The percent of cleaving embryos was significantly increased by 27.9% (p = 0.03) in the N-stop cycle, as embryo morphology was improved by 22% (p = 0.02). The efficacy of gonadotropin treatment was enhanced in the N-stop cycle, as expressed by a 32.5% increase in oocytes retrieved per hMG ampoule administered (p = 0.04). Three cycles of 36 were cancelled during the N-stop cycle, whereas only one was cancelled in the standard protocol cycle. Of the 36 patients, 7 conceived in the N-stop protocol and 5 are ongoing pregnancies. CONCLUSION: Discontinuation of GnRH-a during ovarian stimulation for IVF has a beneficial, but not statistically significant, effect on both E2 and oocyte production. Embryo cleavage rates and morphology were significantly improved, this may be due to improved oocyte quality, which may have been responsible for achieving pregnancies. The efficacy of gonadotropin treatment was enhanced when GnRH-a was discontinued. These results hint that GnRH-a may have a direct negative effect on folliculogenesis and oocytes, which is apparent especially in poor responder patients.

Adult↗
PubMed2001

The relationship between active renin concentration and plasma renin activity in Type 1 diabetes.

AIMS: Circulating activity of the renin-angiotensin-aldosterone system (RAAS) can be assessed by measuring plasma active renin concentration (ARE), as well as by measuring plasma renin activity (PRA). We aimed to assess the relationships between ARE and PRA in Type 1 diabetic compared with non-diabetic control subjects. We also assessed concentrations of the active renin precursor, prorenin. PATIENTS AND METHODS: Thirty-five Type 1 diabetic subjects and 34 non-diabetic control subjects were assessed. Groups had similar ages, sex distributions, body mass indices, systolic and diastolic blood pressures. PRA was measured by radioimmunoassay of angiotensin I generation from endogenous substrate. ARE and total renin concentration (TRE) were measured by immunoradiometric assay (Nichols Institute Diagnostics, USA). Prorenin concentration was calculated as the difference between ARE and TRE. RESULTS: PRA was significantly lower in Type 1 diabetic than in control subjects (0.8 (0.4-1.1) vs. 1.1 (0.9-1.9) pmol/ml per h; P < 0.005), while ARE was similar (17 (9-33) vs. 18 (15-25) mU/l; P = 0.548). PRA (loge transformed) correlated strongly with ARE in diabetic (r = 0.49; P = 0.003) and control subjects (r = 0.59; P = 0.0002), but there was significant vertical separation of the regression lines for the two groups (P < 0.0001). Prorenin concentrations were significantly higher in Type 1 diabetic subjects (249 (170-339) vs. 171 (153-219) mU/l; P = 0.005). Diabetic subjects with high prorenin concentrations (> 400 mU/l (control mean + 3 SD)) were more likely to have microalbuminuria (P = 0.027) and peripheral neuropathy (P = 0.049). CONCLUSIONS: Type 1 diabetes is associated with an altered relationship between ARE and PRA, such that ARE is higher for a given PRA compared with non-diabetic control subjects. Both ARE and PRA are used to assess circulating RAAS activity. The altered relationship between the two in Type 1 diabetic subjects suggests that neither parameter alone is necessarily an adequate and reliable index of such activity. Higher prorenin concentrations, particularly in association with microvascular complications, were confirmed in the Type 1 diabetic subjects. Diabet. Med. 18, 451-458 (2001)

Adult↗
PubMed2001

Pemphigoid nodularis associated with autoantibodies to the NC16A domain of BP180 and a hyperproliferative integrin profile.

Pemphigoid nodularis, a rare variant of bullous pemphigoid, has clinical features resembling prurigo nodularis, with blisters arising from normal-appearing or nodular skin. The fine antigenic epitope of the autoantibodies and the mechanism accounting for the nodular phenotype has not been delineated. We describe a patient with pemphigoid nodularis that fulfilled the criteria of bullous pemphigoid by histopathologic examination and direct and indirect immunofluorescence studies. Immunopathologic examination also revealed in situ deposition and circulating autoantibodies of all IgG subclasses, except IgG3, and both light chains to the patient's skin basement membrane. By immunoblotting, the patient's IgG autoantibodies labeled BP180, BP230, and an unidentified 150-kd epidermal protein and mapped the BP180 epitope to the MCW-1, region 2 of the NC16A domain. The nodular plaque skin showed expression of alpha-6 and beta-1 integrin subunits, mediators of matrix-cell signaling and proliferation, at the basal and the suprabasal epidermis, a pattern found in psoriasis, which is the prototype of hyperproliferative dermatoses.

Aged↗