Biomedical subjects
Publications and source records attributed to D Mortimer.
The paper describes a hexagonal array of nuclear pores in a non-redundant region of the nuclear envelope underlying the basal surface of the rat spermatozoon head. It is concluded that intranuclear material protruding through these pores is the cause of the characteristic rows of circular 'bumps' found in surface replicas of this region.
The outcome of homologous in vitro tests of human sperm penetration into cervical mucus in couples undergoing infertility investigations have been shown to be correlated with the proportion of morphologically normal spermatozoa in the semen samples used for the tests. In addition, the ejaculates producing poor tests contained significantly more spermatozoa with defective tails than those semen samples producing normal or, surprisingly, negative tests.
Suspensions of seminal plasma-free human spermatozoa were prepared by swim-up from semen and studied using high magnification videomicrography after incubation under capacitating conditions for 1.5-2 h. Three subpopulations of capacitating spermatozoa showing different patterns of motility could be distinguished visually: forward progressive, transition phase, and hyperactivated motility. The purpose of this study was not to determine the relative proportions of spermatozoa in these three categories but to describe their movement characteristics. Manual track plotting and analysis allowed value derivation for the curvilinear, average path and straight-line velocities (VCL, VAP, and VSL respectively); for the three progression ratios of linearity (LIN = VSL divided by VCL X 100), straightness (STR = VSL divided by VAP X 100), and wobble (WOB = VAP divided by VCL X 100); and also for the amplitude of lateral head displacement (ALH) and the beat/cross frequency (BCF). Algorithms produced from these motion characteristics allowed distinctions to be made between cell motility patterns. Spermatozoa with straight-line velocity (VSL) greater than or equal to 40 microns/s, linearity (LIN) greater than or equal to 60% and amplitude of lateral head displacement (ALH) less than 5 microns were FP or non-hyperactivated. Tracks with curvilinear velocity (VCL) greater than or equal to 100 microns/s, linearity (LIN) less than 60% and amplitude of lateral head displacement (ALH) greater than or equal to 5 microns showed concomitants of hyperactivation. Classical hyperactivated tracks also showed straightness (STR) less than 60% and straight-line velocity (VSL) less than 30 microns/s.
Leakage of glutamic-oxaloacetic transaminase (GOT) can be used as an indicator of cryo-damage for mammalian spermatozoa. However, two GOT isozymes exist: mitochondrial (m-GOT) and cytosolic or soluble (s-GOT), with acid and alkaline pH optima, respectively. The levels of these GOT isozymes were determined in samples of cell-free human seminal plasma and sperm extracts over a pH range of 3.8 to 9.6. Optimum GOT activities were found at pH 5.2 using cacodylate-HCl buffer (m-GOT) and pH 8.4 using barbital buffer (s-GOT). Differential inhibition studies with adipate (which inhibits s-GOT) were misleading because of the presence of another NADH-linked enzyme able to use adipate as a substrate. Only relatively low levels of m-GOT could be extracted from human spermatozoa (21.4 +/- 31.5 [SD] mU/10(8) cells vs. 202.3 +/- 49.4 mU/mL seminal plasma; n = 20). Consequently, future studies on GOT leakage should be carried out at the alkaline pH optimum, and will therefore measure s-GOT, making this a marker for plasma membrane integrity rather than a measure of mitochondrial damage.
The study consisted of a randomized, controlled trial of synchronized hysteroscopic insemination of the fallopian tube (SHIFT), in which selected infertile couples underwent hormonal delay of menstruation, ovulation induction, and insemination of a selected motile sperm population into the tubal isthmus above the utero-tubal junction. Of 40 couples recruited, only 2 became pregnant, both during a nonsynchronized control cycle. No conceptions were reported in either the 72 SHIFT or 73 non-SHIFT synchronized cycles. Hysteroscopic insemination was found to be a relatively easy procedure with a low rate of technical failure. There was low morbidity with no major clinical complications. However, 57% of tracked synchronized cycles showed a failed response to the follicular stimulation protocol; and 91% showed failure of follicular rupture greater than or equal to 52 hours after hCG induction. These failures of the ovulation synchronization/induction regimen were probably due to the use of medroxyprogesterone acetate for cycle synchronization, and should not preclude further evaluation of the technique of hysteroscopic insemination.