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Gary N Clarke

Publications and source records attributed to Gary N Clarke.

4 recordsLinked to original sources
PubMed2004

Flow cytometry and microscopic acridine orange test: relationship with standard semen analysis.

Improved prediction of male fertility requires advances in semen analysis. This study examined the reproducibility and independence of the flow cytometry acridine orange test (FCM-AOT) of sperm chromatin integrity as an assessment of semen quality. The study found that FCM-AOT results are not significantly affected by up to 6 h delay in semen preparation (n = 9) or contamination of semen with moderate concentrations of bacteria (<10(8)/ml E. coli or Staph. epidermidis, n = 14). The variation of replicate measurements within samples was low (%Abnormal alpha(t): SD = 1.4, 95%CI = 4.6, n = 25) and different samples from the same men were mostly within the range of measurement error (n = 35). FCM-AOT variables, in particular %Abnormal alpha(t), displayed significant correlations with motility (r = -0.557), vitality (r = -0.469) and morphology (r = -0.464, n = 201), which are similar in magnitude to those existing between the standard semen variables. Surprisingly, no correlation was found between %Abnormal alpha(t) and the microscopic acridine orange test (M-AOT) (n = 185), suggesting the FCM results are sensitive to a different aspect of sperm quality. In summary, this study confirms that although not totally independent of standard semen analysis or the M-AOT, it is found to be a robust, sensitive and reproducible measure of semen quality, representative of the individual.

Acridine Orange↗
PubMed2003

Analysis of HIV-1 viral load in seminal plasma samples.

BACKGROUND: With HIV-1-infected individuals now facing the prospect of relatively long and healthy lives, many discordant couples (where the male is HIV-1 seropositive) are seeking to have children. To assist reducing the risks of heterosexual and subsequent vertical transmission in this situation, quantification of HIV-1 viral load in seminal plasma may be effective as one of several measures to reduce the risk of infecting the mother during insemination, potentially providing a better indication of infectivity than blood plasma analysis. OBJECTIVE(S): To modify existing molecular methods for the purpose of analysing HIV-1 viral load in seminal plasma. METHODS: Two commercial assays for HIV-1 RNA quantification were used to assess their sensitivity, specificity and precision for quantification of seminal plasma samples. Seminal plasma samples were prepared with an additional centrifugation step to aid removal of inhibitors to molecular assays. RESULTS: Seminal plasma samples exhibited specificity of >95%, equivalent to that reported by the manufacturers of the commercial assays. With additional centrifugation, complete inhibition of 2/19 (10%) seminal plasma samples was observed using the RT-PCR assay, and inhibition was not apparent in the bDNA assay. Quantification of HIV-1 RNA in seminal plasma samples in both assays was equivalent to that observed in plasma samples and did not appear to be affected by the additional centrifugation step. CONCLUSION: Minor modification of the RT-PCR assay procedure by additional centrifugation of seminal plasma improved the sensitivity of the assay. Inhibition was not apparent with the bDNA assay.

Female↗
PubMed2003

Semen analysis: its place in modern reproductive medical practice.

Semen analysis is the most important laboratory investigation for men when assessing the infertile couple. Advances in in vitro fertilisation (IVF) techniques, particularly intracytoplasmic sperm injection (ICSI) involving the direct injection of a single spermatozoon into an egg, have not diminished the role of semen analysis in modern reproductive practice. Semen analysis is the most basic laboratory investigation undertaken and is descriptive in terms of semen volume, appearance, viscosity, sperm concentration, sperm motility and morphology. Since the results are used by clinicians to choose appropriate treatment options, a reliable service is imperative. It is crucial that the laboratory is experienced in the performance of semen analyses to ensure an accurate result. To ensure a quality semen analysis service, laboratories must participate in internal and external quality assurance activities, incorporate rigorous training protocols for technical staff and use reliable procedures. The World Health Organization laboratory manual for the examination of human semen and sperm cervical mucous interaction, clearly describes the variables that need to be assessed and the methods of analysis and quality assurance to be used.

Humans↗