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Biomedical subjects

M Mason

Publications and source records attributed to M Mason.

At least 55 records · Page 3Linked to original sources
PubMed1998

Radiofrequency ablation of a fascicular tachycardia after orthotopic cardiac transplantation.

A 51 year old male received an orthotopic transplant because of end stage ischaemic heart disease. The donor was a healthy male teenager with no history of arrhythmias or other cardiac conditions. The patient presented with haemodynamically stable tachycardia and dyspnoea five weeks post-transplant. The ECG showed a regular tachycardia of 140 beats/min with a right bundle branch block morphology, left axis deviation, and a QRS duration of 135 ms. There were independent P waves, capture, and fusion beats confirming the diagnosis of ventricular tachycardia. Endomyocardial biopsy showed moderate focal rejection that was thought to be responsible for the arrhythmia. During the following six months the patient had recurrent tachyarrhythmias; on each occasion the ECG morphology was the same and there was no cellular rejection. The patient continued to have frequent hospital admissions with ventricular tachycardia requiring DC cardioversion despite the empirical use of amiodarone, sotalol, disopyramide, and procainamide. Eighteen months after transplantation the diagnosis of fascicular tachycardia was suspected by ECG morphology and supported by successful termination with intravenous verapamil. The arrhythmia was successfully managed by radiofrequency ablation. This patient shows that arrhythmias following transplantation are not always related to rejection, and that other potentially reversible causes should be considered, particularly when the ECG during arrhythmia conforms to a classic configuration.

Catheter Ablation↗
PubMed1998

Suicide prevention effects associated with clozapine therapy in schizophrenia and schizoaffective disorder.

OBJECTIVE AND METHODS: Suicide is a significant cause of death among patients with schizophrenia and schizoaffective disorder, affecting some 10 to 15 percent of these patients. This study examined annual suicide rates over a two-year period (1993-1995) among more than 30,000 patients with schizophrenia and schizoaffective disorder who received services from the Texas Department of Mental Health and Mental Retardation and suicide rates over a six-year period (1991-1996) among a subgroup of patients treated with clozapine. RESULTS: The annual suicide rate for all patients with schizophrenia and schizoaffective disorder was 63.1 per 100,000 patients, approximately five times higher than in the general population. In contrast, only one suicide occurred in six years among patients treated with clozapine who were of similar diagnosis, age, and sex, for a suicide rate of about 12.7 per 100,000 patients per year. This rate is similar to the 15.7 per 100,000 patients per year for all U.S. patients treated with clozapine, calculated from data reported as of June 1996 to the clozapine national registry system maintained by Novartis Pharmaceuticals Corporation, the U.S. manufacturer of clozapine. CONCLUSIONS: The study results suggest that clozapine therapy is associated with a reduced risk of suicide among patients with schizophrenia and schizoaffective disorder.

Adult↗
PubMed1998

Hereditary and sporadic ovarian cancer: genetic testing and clinical implications (review).

The two most common forms of hereditary ovarian cancer are: the breast ovarian cancer syndrome, and ovarian cancer associated with HNPCC (hereditary nonpolyposis colorectal cancer) syndrome. Studies have shown that these diseases may be associated with mutations in a number of tumor suppressor genes, mainly BRCA1 and BRCA2. Malfunction of the protein products of these genes have also been found to be involved in sporadic ovarian cancer, which makes up the majority of ovarian cancer cases. HNPCC-ovarian cancer associated families reveal frequent mutations in at least four genes (hMSH2, hMLH1, hPMS1, and hPMS2) involved in the repair of mismatched DNA. With ovarian cancer being such an important health issue, the push is on to design reliable screening tests to detect defective inherited or somatic alleles in individual carriers. So far, most progress has been demonstrated in those patients with family histories of the disease who are at increased risk. The ramifications of such research may impact a variety of scientific, clinical, legal, ethical, and psychosocial issues. In addition to current treatment modalities, positive results of these tests may indicate the need for increased clinical surveillance, prophylactic treatment, and genetic counseling of patients on an individual basis. It remains to be seen whether the technology can be made reliable enough to not only benefit high-risk individuals but also the general population.

BRCA2 Protein↗
PubMed1998

Psychiatric hospital utilization in patients treated with clozapine for up to 4.5 years in a state mental health care system.

OBJECTIVE: We wished to study long-term psychiatric hospital utilization in a large sample of patients with schizophrenia and/or schizoaffective disorders who were treated with clozapine for up to 4.5 years, and to determine whether or not the reduction in hospital utilization we previously observed in smaller groups for up to 2.5 years was sustained with larger groups and in the longer term. METHOD: Patients in Texas state hospitals who had schizophrenia and/or schizoaffective disorder took either clozapine or traditional antipsychotics for 1.5 to 4.5 years. The number of patients in the clozapine group ranged from 383 (1.5 years of treatment) to 29 (4.5 years). The group of patients who took traditional antipsychotics was made up of all patients (N = 233) with similar diagnoses, symptom severity, and duration of illness present in Texas state hospitals on an index day. RESULTS: The clozapine group showed a rapid and continuing decrease in hospital bed-days compared with controls who took traditional antipsychotics. The number of clozapine-treated patients who required little or no hospitalization during successive 6-month periods became significant (p < .0001) within 1.5 years, and continued to increase. Conversely, the number of patients taking clozapine who required virtually continuous state hospitalization decreased markedly compared with those taking traditional antipsychotics. CONCLUSION: Potential hospital cost savings are substantial, even though overall group results are diluted by clozapine nonresponders. Most treatment costs for clozapine nonresponders were related to hospital care; most or all of such costs would have been present in any event had these patients remained on traditional antipsychotic therapy. We believe a trial of clozapine therapy provides a low-cost opportunity for a highly effective and highly cost-saving outcome in those patients who will favorably respond to this therapy. We discuss clinical, social, and economic advantages of modern pharmaceutical treatments over traditional drugs.

Antipsychotic Agents↗
PubMed1998

ECT in Texas: 19 months of mandatory reporting.

BACKGROUND: Texas law requires that all non-federal clinical facilities providing electroconvulsive therapy (ECT) report every treatment to the state's mental health agency. The resulting data provide total population information about treating physicians and hospitals; payment source; patient age, sex, ethnicity, diagnosis, and admission/consent status; symptom severity and response; numbers and types of treatments; and untoward events occurring within 14 days after treatment. METHOD: We reviewed all reports of ECT between September 1993 and April 1995 (2583 reports, approximately 15,240 treatments). RESULTS: About 6% (N = 117) of Texas psychiatrists performed ECT during the period, at 50 hospitals. One of 13 state-funded mental institutions performed ECT on-site; some occasionally contracted with private hospitals. Almost all patients (88.1%) were white. Some older age groups received proportionately more ECT than younger groups, but no sharp increase was associated with eligibility for Medicare. Five patients were less than 18 years of age; 70.3% were female. Virtually all patients (99.0%) consented to the treatment themselves (rather than by guardian), including committed-but-consenting patients (1.5%). Reports (5.8%) described multiple-monitored treatment (MMECT, not depatterning). Group data indicated generally good-to-excellent response, as measured by a five-point symptom-severity scale. Eight patients died within 14 days of a treatment, 2 possibly of anesthesia complications and 3 others in accidents or by suicide. Four were receiving maintenance treatments (generally about every other week). No death appeared related to ECT stimulus or seizure. CONCLUSION: ECT in Texas is performed by a small minority of psychiatrists and is unavailable to many patients who need it. It is most accessible to white patients who receive care outside the public sector. Our data support the common finding that ECT is generally safe and effective.

Adolescent↗
PubMed1997

Effect of photodynamic therapy in combination with mitomycin C on a mitomycin-resistant bladder cancer cell line.

Photodynamic therapy is a method for treating cancer using drugs activated by light. A new compound, 5-aminolaevulinic acid (ALA), is a precursor of the active photosensitizer protoporphyrin IX (PpIX) and has fewer side-effects and much more transient phototoxicity than previous photosensitizers. Cell survival of ALA-mediated photodynamic therapy was measured in the J82 bladder cancer cell line, along with its mitomycin C-resistant counterpart J82/MMC. This demonstrated that mitomycin resistance is not cross-resistant to photodynamic therapy. There was also a suggestion that the mitomycin-resistant cells were more susceptible to photodynamic therapy than the parent cell line. Photodynamic therapy appeared to enhance the effect of mitomycin C, when mitomycin C was given first. This phenomenon was apparent for both drug-resistant and drug-sensitive cell lines. This suggests a possible role for combined mitomycin C and photodynamic therapy in superficial bladder tumours that have recurred despite intravesical cytotoxic drug treatment.

Aminolevulinic Acid↗
PubMed1997

Photodynamic therapy of bladder cancer cell lines.

OBJECTIVE: To determine the effect of photodynamic therapy mediated by 5-aminolevulinic acid (ALA) on a range of bladder cancer cell lines, including a squamous cancer cell line and a multi-drug resistant cell line. MATERIALS AND METHODS: Experiments were performed on cells growing in culture: the cell lines studied were the transitional cell cancer lines RT112, T24 and EJ138, the squamous cancer cell line, SCaBER, and the multi-drug resistant transitional cancer cell line, MGH-U1(R), together with its non-resistant parent line, MGH-U1. The kinetics of the ALA-mediated generation of fluorescent photosensitizer were determined using flow cytometry. Photodynamic therapy was performed by incubating cells in ALA followed by exposure to various doses of white light. RESULTS: The response of the various transitional cancer cell lines to photodynamic therapy depended on dose. The squamous cell line was relatively resistant to photodynamic therapy. There was some cross-resistance of the MGH-U1(R) cell line to photodynamic therapy, although the mechanism of cross-resistance appeared not to be necessarily a property of the drug-resistant phenotype. CONCLUSION: This study suggests that ALA-mediated photodynamic therapy may be effective in transitional cell carcinoma of the bladder. Based on these findings, this therapeutic method should be further evaluated clinically.

Aminolevulinic Acid↗
PubMed1997

Evaluation of an immunoenzymometric assay (IEMA) using automated system for determination of luteinizing hormone and follicle stimulating hormone.

It has been proposed that automated systems for immunoenzymometric assay (IEMA) may substitute traditional radioimmunoassay (RIA) for measurement of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in blood due to the advantage of being more rapid, higher sensitivity, lower cost and not requiring radioactive reagents. The study was designed to evaluate both systems using serum samples to determine luteinizing hormone (LH) and follicle-stimulating hormone (FSH) concentrations. The automatic system (ES-300) for IEMA utilized two monoclonal antibodies, one of them on the solid phase was the specific extractant for the antigen, and the other was a peroxidase labeled antibody which recognizes a different epitope in the antigen molecule, specifically bound in linear proportion to the antigen concentration. Blood samples were obtained from patients who were treated at the hospital for various clinical problems ("problem group") as well as blood samples from patients in whom FSH and LH concentrations were already known ("high", "medium" and "low" levels) by previous RIA ("control group"). IEMA showed a higher sensitivity, 0.42 and 0.96 mIU/ml for FSH and LH, respectively, whereas RIA was 1.95 mIU/ml for both hormones. Intra- and interassay coefficient of variation were below 10% within the range of 15-150 mIU/ml for FSH and 5-100 mIU/ml for LH; however, the coefficient of variation was 15-25% at lower concentrations of FSH and LH. Accuracy of IEMA was evaluated by recovery percentage, thus when high and medium concentrations of FSH and LH were analyzed the recovery was between 99-104%. On the other hand, the recovery was 110% when low levels of FSH and LH were used. In conclusion, IEMA resulted reliable when FSH and LH concentrations are in the middle and high range; likewise, the detection limit of IEMA was lower than RIA, particularly for FSH. On the bases of these results, IEMA showed several advantages over RIA, but its reliability diminishes when serum samples contain low FSH and LH concentrations. It is important to extend these studies to steroid assays and elaborate a database in each laboratory.

Adult↗
PubMed1997

Childhood sexual and physical abuse. Incidence in patients with vulvodynia.

OBJECTIVE: To compare the incidence of sexual and/or physical abuse in women with vulvodynia (chronic, burning vulvar pain in the absence of clear medical findings) as compared to women with chronic vulvar symptoms due to specific, objective vulvar disease and with women from a general dermatology practice. STUDY DESIGN: An invitation to participate in this questionnaire study was sent to 300 women over 18 years of age from a vulvo-vaginal clinic and 280 women from a general dermatology practice. These questionnaires asked for basic demographic information as well as information on childhood sexual experiences and physical abuse. RESULTS: Questionnaires from 89 patients with vulvodynia, 65 patients with chronic vulvar symptoms due to specific, objective vulvar disease and 166 patients from a general dermatology practice were examined. There were no differences as to the incidence of childhood sexual or physical abuse between patients with vulvodynia and either those with general dermatology complaints or those with chronic vulvar symptoms due to objective disease. CONCLUSION: There is no evidence from these data that women with vulvodynia experience a higher incidence of sexual or physical abuse during childhood as compared to women in a general dermatology office or women with chronic vulvar symptoms from specific, observable pathology.

Adult↗
PubMed1997

Informed consent.

Explore the source record for details and available documents.

Consent Forms↗
PubMed1997

[The proportion of molecular forms of gonadotropins changes in patients with polycystic ovaries].

It is known that protein hormones circulate as different molecular forms and the relative proportion of these isoforms changes according to endocrine milieu. In particular gonadotropins, both LH and FSH, isoforms suffer variations related to the estrogen levels; thus sera obstained from menopausal women show a predominance of larger molecular forms which are considered as having lesser biological activity and the administration of estrogen replacement therapy is followed by the appearance of intermediate molecular forms possessing higher biological activity. This chormatographic pattern with predominance of intermediate isoforms is typical at midcycle in sera from normal women at the periovulatory stage. Present study showed that sera obtained from anovulatory women, such as patients with polycystic ovaries a predominance of larger and smaller molecular weight isoforms, exhibiting a chromatographic pattern different from that observed in normal women. It is speculate that there is some imbalance between the ovarian steroid synthesis and gonadotropin production in the stage of tertiary structural conformation.

Adult↗
PubMed1996

[Variations in the molecular forms of LH and FSH during the normal ovarian cycle].

FSH and LH concentrations during the menstrual cycle are well known, showing characteristically a midcycle surge in LH as well as in less degree in FSH. At the present there is an increasing interest in studying variations of the moleculoar forms of both gonadotropins. We have studied the chromatographic profile of FSH and LH in sera obtained from women regularly ovulating and in patients with anovulatory cycles by the use of gel column chromatography. It was observed the predominance of LH 32-34 kDa at midcycle and the heterogeneous FSH profile during the ovarian cycle. In sera from anovulatory patients the chromatographic profile was even more irregular for both LH and FSH. It is concluded that LH 32-34 kDa may be the more biological isoform in turn related with the process of ovulation.

Adult↗
PubMed1995

The isolation of Campylobacter jejuni from contaminated surfaces and its survival in diluents.

The isolation rates of campylobacters from contaminated surfaces were improved if swabs were placed directly into selective media rather than being stored in diluents before culture. Storage in diluents resulted in a loss of viability and the remaining viable campylobacter cells were often sub-lethally injured which sensitised them to selective agents in culture media and reduced isolation rates. Campylobacter jejuni, suspended in small drops of blood, was capable of prolonged survival on work surfaces if the drops remained liquid but the bacterium died rapidly once drops had dried.

Campylobacter jejuni↗
PubMed1995

Patients with TSH-secreting pituitary tumor possess different TSH molecular isoforms.

The objective of the study was to demonstrate if TSH secreted by a pituitary tumor correlates with particular molecular forms of TSH. Aliquots of sera from two hyperthyroid patients with TSH-secreting pituitary tumor were subjected to gel filtration chromatography to be assayed for TSH. The assay was repeated in one case after transsphenoidal adenomectomy. Sera from two additional patients with long-lasting primary hypothyroidism, and from two subjects with normal thyroid function were also chromatographed. Molecular weight (mol wt) of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, mol wt, and partition coefficient. Chromatographic profile of the two cases with TSH-secreting pituitary tumor exhibited mainly two peaks of TSH immunoreactivity. The major component of immunoreactivity eluted as a peak corresponding with the alpha-subunit of the glycoprotein. This pattern was different from that obtained in sera from two women with hypothyroidism, which was heterogeneous and presented a predominance of molecular variants corresponding with mol wt of 22 and 29 kD, and no alpha-subunit was present. In cases of normal thyroid function the chromatographic profile showed that the major proportion of TSH eluted simultaneously with the labeled standard and 22 kD marker. These results demonstrate that TSH secreted by pituitary tumors is composed of various molecular forms and the alpha-subunit is the major component. This chromatographic profile is different from that observed in other cases with elevated concentrations of TSH as it occurs in primary hypothyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗