Tail beat frequency of human sperm: evaluated with sperm head fixation method and computer-assisted semen analysis

Bioinspired microrobots: Opportunities and challenges in targeted cancer therapy

Chemotherapy is still the most effective technique to treat many forms of cancer. However, it also carries a high risk of side effects. Numerous nanomedicines have been developed to avoid unintended consequences and significant negative effects of conventional therapies. Achieving targeted drug delivery also has several challenges. In this context, the development of microrobots is receiving considerable attention of formulation scientists and clinicians to overcome such challenges. Due to their mobility, microrobots can infiltrate tissues and reach tumor sites more quickly. Different types of microrobots, like custom-made moving bacteria, microengines powered by small bubbles, and hybrid spermbots, can be designed with complex features that are best for precise targeting of a wide range of cancers. In this review, we mainly focus on the idea of how microrobots can quickly target cancer cells and discuss specific advantages of microrobots. A brief summary of the microrobots' drug loading and release behavior is provided in this manuscript. This manuscript will assist clinicians and other medical professionals in diagnosing and treating cancer without surgery.

Engineering microrobots for targeted cancer therapies from a medical perspective

Systemic chemotherapy remains the backbone of many cancer treatments. Due to its untargeted nature and the severe side effects it can cause, numerous nanomedicine approaches have been developed to overcome these issues. However, targeted delivery of therapeutics remains challenging. Engineering microrobots is increasingly receiving attention in this regard. Their functionalities, particularly their motility, allow microrobots to penetrate tissues and reach cancers more efficiently. Here, we highlight how different microrobots, ranging from tailor-made motile bacteria and tiny bubble-propelled microengines to hybrid spermbots, can be engineered to integrate sophisticated features optimised for precision-targeting of a wide range of cancers. Towards this, we highlight the importance of integrating clinicians, the public and cancer patients early on in the development of these novel technologies.

Ostrich ejaculate characteristics and male libido around equinox and solstice dates

The study evaluated the effect of time of the year in which changes in photoperiod occurs on ostrich semen characteristics and male libido. Semen was collected for 5 days before, on and 5 days after winter solstice (21 June 2016), spring equinox (22 September 2016), summer solstice (21 December 2016) and autumn equinox (20 March 2017) in the southern hemisphere. Semen was collected from 10 South African Black ostrich males (average age ± standard deviation; 4.5 ± 2.27 years) using the dummy female. Semen volume, sperm concentration, total sperm per ejaculate, sperm motility traits, percentage of normal sperm, head and tail abnormalities and percentage of affected sperm in the hypo-osmotic swelling test (HOS) were evaluated. Male libido defined as the willingness of males to mount the dummy female was also recorded. Semen samples collected around summer solstice, spring and autumn equinox were higher in sperm concentration and sperm output compared with winter solstice (P < 0.05). Study periods did not influence semen volume, sperm motility traits, the percentage of normal sperm, head abnormalities and HOS. Tail abnormalities were higher around winter solstice than around spring equinox (P < 0.05). Male libido and the success of semen collection were significantly higher around spring equinox (P < 0.05). Changes in photoperiod in the southern hemisphere do not affect semen production in ostriches. However, high sperm output and male libido around spring equinox and summer solstice dates suggest that these periods may be preferred for semen collection for artificial insemination and storage purposes.

Impact of kudzu and puerarin on sperm function

The goal of this study was to investigate the impact of kudzu (Pueraria mirifica) and the isoflavone puerarin in functional toxicological tests on spermatozoa and to assess the affinity of extracts and pure isoflavones for estrogen receptor (ER)-alpha and -beta (ERα, ERβ) in receptor binding assays. Capacitation, acrosome reaction and chromatin decondensation in spermatozoa were analyzed using microscopic analysis. Kudzu, but not puerarin, reduced motility of sperm. Puerarin reduced the percent spontaneous acrosome reaction in spermatozoa. The pathways used by kudzu that affect sperm function are not fully mirrored by puerarin. Puerarin, kudzu and its other phytoestrogenic components displayed preferential affinity for ERβ, however the diverse effects of kudzu and puerarin on sperm function implicate the involvement of multiple signaling systems.

Adenosine and Catecholamine Agonists Speed the Flagellar Beat of Mammalian Sperm by a Non-Receptor-Mediated Mechanism1

Activation of rapid motility apparently is one of the first steps of sperm capacitation and can be studied in vitro. Previously we found that 2-chloro-2'-deoxyadenosine or the catecholamine isoproterenol activates mouse sperm motility in vitro via a pathway mediated by cAMP that requires extracellular Ca2+, the atypical sperm adenylyl cyclase, and sperm-specific protein kinase A. We now show that several other adenosine analogs and catecholamines accelerate the flagellar beat of mouse and human sperm. Unexpectedly, the potent adenosine receptor agonist CGS21680 does not accelerate the beat, and the adenosine receptor antagonist DPCPX does not diminish the accelerating action of 2-chloro-2'-deoxyadenosine. The pharmacological profile for activation by catecholamines is also unusual. Both agonists and antagonists of beta-adrenergic receptors elevate the beat frequency. Moreover, both l-(-) and d-+ isomers of epinephrine, norepinephrine, and isoproterenol produce similar acceleration of the beat. In contrast, inhibitors of equilibrative nucleoside transporters effectively slow the onset of the accelerating action of adenosine analogs. Replacement of external Na+ with Li+ also diminishes the accumulation of cAMP and slows the resultant accelerating action of 2-chloro-2'-deoxyadenosine, suggesting the involvement of a Na+-dependent concentrative nucleoside transporter. Our results show that adenosine and catecholamine agonists act in a novel signaling pathway that does not involve G protein-coupled cell-surface receptors that link to conventional adenylyl cyclases. Instead, adenosine and analogs may be transported into sperm via equilibrative and concentrative nucleoside transporters to act on unknown intracellular targets.

Mechanism of action of some acrylophenones, quinolines and dithiocarbamate as potent, non-detergent spermicidal agents

Some suitably substituted acrylophenones, quinolines and dithiocarbamate were synthesized as new generation, non-detergent spermicides and were studied for their mechanism of action in comparison with various known spermicides belonging to several different classes of chemical compound. Nonoxynol-9, benzalkonium chloride, Sapindus saponins, verapamil, emetine and tartaric acid were used as reference molecules to study the effect of new spermicides on human sperm motility parameters (using computer-assisted semen analyzer), plasma membrane integrity, lipid peroxidation and defense system against reactive oxygen species (ROS). Results have indicated that sperm plasma membrane remains the primary site of action of most of the spermicides, though the effect may be predominantly on the physiological integrity rather than the structural integrity in case of the new compounds. Lipid peroxidation may play an important role in disrupting sperm membrane physiology that may or may not be accompanied with a detrimental effect on the defense system of the human spermatozoa against the ROS.

Autostage sperm tracing system for semen evaluation

To overcome the limitation of the microscope field, the study proposed an autostage sperm tracing system (ASTS), which could trace a particular sperm for a long time and distance. The ASTS was constructed by assembling a commercial microscope, an image frame grabber, a personal computer, and a motorized stage. Its performance was tested by evaluating 6 semen samples and by comparing the evaluation with those of other semen evaluations. The ASTS broke through the limitation of the microscope field and traced a particular sperm as long as possible. It analyzed the sperm track and calculated the motility parameters, such as curvilinear velocity (Vcl), straight-line velocity (Vsl), and linearity (L(in)). The sperm quality was then evaluated in real time, and the user could decide to capture or abandon a particular sperm in the IVF The ASTS enables users to evaluate sperm progression for a long time and to have the global quality of a particular sperm in real time. Its open structure has the flexibility for micromanipulating a semen sample, and has the potential application associated with a modern IVF technique.

Direct measurement of the tail beat frequency of human sperm by flash light synchronization

Based on the synchronization between a periodic vibration and flashing light, we designed a device to determine the flagellar beating frequency of human sperm. The head of a spermatozoon was either held by the tip of a micropipette operated with a micromanipulator or adhered by itself on the surface of a glass slide when the sperm swam out of the micropipette into the fresh Ham's F-10 medium. The beat frequency of the flagellum was measured by synchronization of the frequency-adjustable flash light built on an inverted microscope. The light frequency synchronizer included a controller, a pulse generator, a signal counter, and a flash illuminator. During each measurement, the spermatozoon was transferred to the center of the observing field and the frequency generator created a series of signals which developed flashing signals onto the sample plane. When the vibration of the flagellum was observed as a constant two-step-like movement after frequency adjustment, the beating frequency was read from the signal counter and the count was twice that of the beat frequency of the sperm tail. As the flash signal was decreased to half of this frequency, an apparently immobilized sperm flagellum was observed and the exact beating frequency could then be determined. This device was then used to measure the effect of pentoxifylline on sperm motility. The results showed that the increase of tail beat frequency as measured by this device is well correlated with the increase of beat cross frequency as detected by a computer-assisted semen analyzer. These findings suggest that this flash light synchronization device is a reliable and useful system for the assessment of sperm motility.

Magnolol protects human sperm motility against lipid peroxidation: a sperm head fixation method

It was previously reported that magnolol, isolated from the Chinese medicinal herb Magnolia officinalis, had a potent inhibitory activity on lipid peroxidation. Since sperm motility could be suppressed by lipid peroxidation, this study examines the protective effect of magnolol on lipid peroxidation-suppressed sperm motility. FeSO4 was used to induced lipid peroxidation and sperm motility was expressed as tail beat frequency (TBF) measured with a sperm head fixation method. Magnolol at 10(-9) to 10(-7) M significantly reversed the FeSO4-suppressed TBF. Magnolol significantly inhibited the generation of malondialdehyde (MDA), the end product of lipid peroxidation, in sperm. Magnolol protected sperm motility by inhibiting lipid peroxidation in sperm.