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Biomedical subjects

G T Kovacs

Publications and source records attributed to G T Kovacs.

At least 19 recordsLinked to original sources
PubMed2003

Adolescence and other risk factors for Chlamydia trachomatis genitourinary infection in women in Melbourne, Australia.

OBJECTIVE: To establish the prevalence of and risk factors for Chlamydia trachomatis infection to determine the role of universal versus targeted testing. METHODS: A prospective study of 1107 women attending two sexual and reproductive health clinics in Melbourne, Australia, was carried out. A questionnaire was used to establish risk factors. Urine samples were tested for C. trachomatis by PCR. The main outcome measures were prevalence of and risk factors for C. trachomatis infection. RESULTS: Of 1107 recruitable women, 851 (76.9%) consented and were successfully tested. C. trachomatis was detected in 18 (4.8% (95% CI 2.9 to 7.5)) of 373 women in the inner city and eight (1.7% (95% CI (0.7 to 3.3)) of 478 women in the suburban clinic. Of women under 25 years, 17 (6.2% (95% CI 3.7 to 9.8)) of 273 in the inner city in contrast with three (1.7% (95% CI 0.4 to 5.0)) of 174 in the suburban clinic were infected. In the inner city clinic, age under 25 years (OR 5.4 (95% CI 0.7 to 41.5)), vaginal discharge (OR 4.1 (95% CI 1.5 to 11.1)), and recent change of sexual partner (OR 4.6 (95% CI 1.6 to 12.9)) were associated with C. trachomatis. In contrast, in the suburban clinic, only vaginal discharge (OR 3.5 (95% CI 0.9 to 14.3)) and recent change of sexual partner (OR 3.4 (95% CI 0.8 to 15.7)) were identified as risk factors. Multivariate analysis showed that recent change of partner (OR 4.5 (95% CI 1.5 to 13.8)) was the most strongly associated independent risk factor for infection in the inner city clinic. CONCLUSION: The high prevalence of C. trachomatis indicates that universal testing should be undertaken in the inner city clinic. Young age may not be a risk factor for C. trachomatis in more affluent populations with lower prevalence rates. No risk factors were identified with sufficient sensitivity and specificity to be useful for targeted testing. Prevalence and identifiable risk factors for C. trachomatis are not transferable between populations, even in the same city.

Adolescent↗
PubMed2002

Surgical or medical treatment of polycystic ovary syndrome: a cost-benefit analysis.

With the availability of laparoscopic ovarian cautery, there has been a resurgence in interest in the surgical treatment of clomiphene citrate-resistant polycystic ovary syndrome (PCOS). Comparison of ovulation and pregnancy rates has found no difference in success rates between ovarian cautery and gonadotropin ovulation induction for such women. We have therefore compared the cost of laparoscopic ovarian cautery with that of a typical cycle of gonadotropin ovulation induction, and also found that there is little difference. Because of the potential advantages of ovarian cautery, we recommend this surgery as the next line of treatment if clomiphene citrate fails to induce ovulation in PCOS patients, before gonadotropins are introduced.

Cautery↗
PubMed2001

Lysing bacterial spores by sonication through a flexible interface in a microfluidic system.

Cell disruptions using ultrasonic energy transmitted through a flexible interface into a liquid region has limitations because the motion of the vibrating tip is not completely transferred into the liquid. To ensure that some degree of contact will be maintained between the ultrasonic horn tip and the flexible interface, the liquid must be pressurized. The pressure conditions that yield consistent coupling between the ultrasonic horn tip and the liquid region were explored in this study by using an analytical model of the system and test fixture experiments. The nature of the interaction between the horn tip and the flexible interface creates pulses of positive pressure rises, increase in temperature, streaming flow, and almost no cavitation in the liquid. There was sufficient energy to create a cloud of microspheres, or beads, that maintain a consistent pattern of ballistic motion in the liquid. The sonication was found to be repeatable by studying video recordings of bead motion and was shown to be statistically consistent using measurements of temperature rise. Sonication of bacterial spores to obtain measurements of released nucleic acid and SEM images of damaged spores were used to verify the effects of liquid pressure on the horn-interface-liquid coupling.

Hydrolysis↗
PubMed2001

Portable cell-based biosensor system using integrated CMOS cell-cartridges.

The use of cell-based biosensors outside of the laboratory has been limited due to many issues including preparation of the sample, maintenance of the biological environment, and integration of the electronics for data collection and analysis. This paper describes a system that addresses several of these issues with the development of an integrated silicon-polydimethylsiloxane cell-cartridge. The cell-cartridge contains a CMOS silicon chip that incorporates a digital interface, temperature control system, microelectrode electrophysiology sensors, and analog signal buffering. Additionally, the cell-cartridge supports two separate cell populations in two 10 microl sealed chambers that have independent fluidic channels for sample injection. A portable, microcontroller-based electronics system capable of monitoring the action potential (AP) activity within the cell-cartridges was also developed. The AP activities of cardiomyocyte syncytia in the two chambers differentially responded to the flow of a control medium versus the flow of a biochemical agent. The cell-cartridges and portable electronics system were used to successfully record AP activity from cardiomyocytes outside of the laboratory under realistic application conditions.

Action Potentials↗
PubMed2001

General purpose, field-portable cell-based biosensor platform.

There are several groups of researchers developing cell-based biosensors for chemical and biological warfare agents based on electrophysiologic monitoring of cells. In order to transition such sensors from the laboratory to the field, a general-purpose hardware and software platform is required. This paper describes the design, implementation, and field-testing of such a system, consisting of cell-transport and data acquisition instruments. The cell-transport module is a self-contained, battery-powered instrument that allows various types of cell-based modules to be maintained at a preset temperature and ambient CO(2) level while in transit or in the field. The data acquisition module provides 32 channels of action potential amplification, filtering, and real-time data streaming to a laptop computer. At present, detailed analysis of the data acquired is carried out off-line, but sufficient computing power is available in the data acquisition module to enable the most useful algorithms to eventually be run real-time in the field. Both modules have sufficient internal power to permit realistic field-testing, such as the example presented in this paper.

Action Potentials↗
PubMed2001

A genetically engineered cell-based biosensor for functional classification of agents.

Cell-based biosensors (CBBs) utilize whole cells to detect biologically active agents. Although CBBs have shown success in detecting the presence of biological agents, efforts to classify the type of agent based on functional activity have proven difficult because multiple biochemical pathways can lead to the same cellular response. However, a new approach using a genetically-engineered cell-based biosensor (GECBB) described in this paper translates this cross-talk noise into common-mode noise that can be rejected. The GECBB operates by assaying for an agent's ability to differentially activate two populations of cells, wild-type (WT) cells and cells genetically engineered to lack a specific receptor, knockout (KO) cells. Any biological agent that targets the knocked out receptor will evoke a response in the WT but not in the KO. Thus, the GECBB is exquisitely sensitive to agents that effect the engineered pathway. This approach provides the benefits of an assay for specific functional activity while simplifying signal analysis. The GECBB implemented was designed to be sensitive to agents that activate the beta 1-adrenergic receptor (beta 1-AR). This was achieved by using mouse cardiomyocytes in which the beta 1-AR had been knocked out. The cellular signal used in the GECBB was the spontaneous beat rate of the two cardiomyocyte syncitia as measured with microelectrode arrays. The GECBB was able to detect the beta-AR agonist isoproterenol (ISO) at a concentration of 10 microM (P<0.005).

Adrenergic beta-Agonists↗
PubMed2001

The use of emergency contraception in Australasian emergency departments.

OBJECTIVE: To review the prescribing of emergency contraception by emergency departments in Australasia and compare it with other providers. METHODS: A postal questionnaire was sent to the director of each of the 79 Australasian College for Emergency Medicine accredited emergency departments in Australasia inquiring about the availability and prescribing habits for emergency contraception within each department. RESULTS: Of the 79 emergency departments, 69 (87.3%) responded to the questionnaire and were aware of the 'emergency contraception regimen'. The majority of departments prescribed appropriately (56%) and only one department did not arrange adequate follow up. Anti-emetics are always used by 45 departments (78.9%). Discussion of future contraceptive needs at the time of presentation was only undertaken by 25 departments (43.9%). Written clinical guidelines for emergency contraception were present in 28 departments (40.6%). CONCLUSIONS: Emergency departments are accessed by patients requesting contraception following unprotected intercourse or contraceptive failure. The prescribing of emergency contraception in Australasian emergency departments is comparable with other providers but substantial improvements could be made. Suggestions to assist this improvement include written clinical guidelines and patient information and purpose-made medication packs.

Antiemetics↗
PubMed2001

Serving rural Australia with reproductive health expertise.

This study aimed to review the use of reproductive health services in Family Planning clinics by women from rural (non-metropolitan) Australia through a retrospective analysis of data collected at clinics of seven state/territory Family Planning Organisations (FPO). From a total of 146 157 client visits to FPO clinics between July 1998 and June 1999, 42 497 (29.1%) were by clients who lived outside metropolitan areas. Some 97% of clients were women. Our results show the use of reproductive health services by women from rural areas was different from the services used by women from metropolitan areas. There were fewer male clients, more women over 40 years of age, and fewer clients from a non-English speaking background. More of the attendees had pension cards and fewer were privately insured. We concluded there is considerable demand for reproductive health services among the rural population and reproductive health care needs to be expanded to reach rural women.

Adult↗
PubMed2001

What is the probability of conception for couples entering an IVF program?

The outcome of 4225 couples undergoing 8207 in vitro fertilisation (IVF) cycles over a six year period has been analysed using life table analysis. Pregnancy was expressed as a 'clinical pregnancy - fetus visible on ultrasound' per stimulated cycle oocyte collection, with pregnancies obtained from frozen embryos being referred to the cycle where they were collected. We found that only 1 in 200 patients proceeded beyond six cycles and the cumulative per cent pregnant was 20.7% after the first cycle, with nearly half pregnant within three and over two-thirds being pregnant within six cycles. We find this is a useful way to present the chance of pregnancy to prospective couples.

Female↗
PubMed2000

A pre-coital pill? A preliminary in vitro study.

The use of the progestogen-only pill as a 'pre-coital contraceptive' was tested by in vitro studies of sperm-mucus interaction. The results suggest that a single tablet of levonorgestrel 30 microg, or norethisterone 350 microg, was effective in preventing sperm migration in the cervical mucus about 12 hours later. This suggests that the progestogen-only pill may be effective as a 'morning before pill'.

Cervix Mucus↗
PubMed1999

A minisonicator to rapidly disrupt bacterial spores for DNA analysis.

Concerns about the use of anthrax spores as a weapon of mass destruction have motivated the development of portable instruments capable of detecting and monitoring a suspected release of the agent. Optimal detection of bacterial spores by PCR requires that the spores be disrupted to make the endogenous DNA available for amplification. The entire process of spore lysis, PCR, and detection can take several hours using conventional methods and instruments. In this report, a minisonicator and prototype spore lysis cartridge were built to disrupt Bacillus spores in 30 s for rapid, real-time PCR analysis. Utilization of the minisonicator improved PCR analysis by decreasing the limit of detection, reducing the time of detection, and increasing the signal amplitude. Total time of spore disruption and detection using the minisonicator and a microchip PCR instrument was less than 15 min.

Bacillus anthracis↗
PubMed1999

Semen storage for special purposes at Monash IVF from 1977 to 1997.

OBJECTIVE: To review 20 years of experience with sperm storage before vasectomy or before chemotherapy and/or radiation therapy (medical storage), and to evaluate its usefulness. DESIGN: Retrospective data analysis. SETTING: University-affiliated reproductive medicine clinic. PATIENT(S): Two hundred fifty-six men who underwent vasectomy and 258 men who underwent chemotherapy and/or radiation therapy. INTERVENTION(S): Review of patient clinical notes. MAIN OUTCOME MEASURE(S): The subsequent use of cryostored sperm and the number of pregnancies that resulted. RESULT(S): Only 4 of the 256 men who underwent vasectomy returned for treatment, and three pregnancies were achieved. Eighteen of the 258 men who underwent chemotherapy and/or radiation therapy returned for treatment, and six pregnancies were achieved. CONCLUSION(S): Only a small proportion of men (2%) returned to use their cryostored specimens after vasectomy, and pregnancy was achieved in most cases. Seven percent of men returned to use their specimens after chemotherapy and/or radiation therapy, and pregnancy was achieved in only one third of cases.

Adolescent↗
PubMed1999

Current concepts of the mechanisms of menstruation.

Menstruation is the process whereby the superficial or functionalis layer of the endometrium lining the uterine cavity disintegrates and is removed from the uterine lumen towards the end of the luteal phase of a non-pregnant cycle. Within a period of 5-6 days the old lining is removed and a new lining regenerated without scarring occurring, a remarkable example of controlled tissue remodelling unparalleled in other organs. This chapter describes the phenomenon of menstruation and tissue repair and reviews the vasoconstrictor and inflammatory hypotheses for the initiation of menstruation. Particular emphasis is placed on the roles of steroids, prostaglandins, endothelin, lysosomal enzymes and matrix metalloproteinases, and the involvement of the fibrinolytic system and apoptosis. Repair of the endometrium is compared to the processes and mechanisms of wound healing.

Adolescent↗
PubMed1999

The use of family planning services by non-English speaking background (NESB) women.

This study was undertaken to determine the proportion of family planning organization clients who are from a non-English speaking background (NESB), to analyse the services they used, and to compare it to the services used by other clients. Analysis of clinic data sheets from the 8 State/Territory family planning organizations (FPO) was conducted. From a total of 185,879 client visits in FPO clinics between July, 1996 and June, 1997, 27,349 (14.7%) were from NESB. The proportion of clients with NESB was quite similar to that in the community. This means that in general, FPOs are reaching their share of clients with NESB. The patterns of reproductive health services used varied between NESB women compared to English speaking women.

Adult↗