Atoltivimab/maftivimab/odesivimab (Inmazeb) combination to treat infection caused by Zaire ebolavirus.

Zaire ebolavirus has been responsible for several catastrophic outbreaks with a high mortality rate. Unfortunately, there were no approved therapies or vaccines to treat or prevent infections caused by Ebola virus (EBOV) or other filoviruses. Atoltivimab/ maftivimab/odesivimab (Inmazeb) is the first Food and Drug Administration (FDA)-approved treatment for Zaire ebolavirus infection in adult and pediatric patients, including neonates born to a mother who is reverse transcription polymerase chain reaction (RT-PCR)-positive for Zaire ebolavirus infection. The efficacy of Inmazeb has been established in vivo and it has successfully completed a phase I clinical trial in healthy individuals with no drug-related adverse effects. Additionally, Inmazeb has displayed significant reduction in mortality in the PALM (PAmoja tuLinde Maisha) trial, when compared with the control arm receiving ZMapp. Inmazeb has received orphan drug designation from both the U.S. FDA and the European Medicines Agency (EMA).

Levonadifloxacin arginine salt to treat acute bacterial skin and skin structure infection due to S. aureus including MRSA.

Acute bacterial skin and skin structure infections (ABSSSIs) are one of the most common types of infections due to methicillin-resistant Staphylococcus aureus (MRSA). The standard of care for ABSSSI includes glycopeptides such as vancomycin, teicoplanin, oxazolidinones and fluoroquinolones, which are potent broad-spectrum antibacterial agents. Unfortunately, due to indiscriminate utilization, resistance to these agents is rising and identification of novel agents is an urgent unmet medical need. In this context, levonadifloxacin (WCK-771) is a novel, hydrate arginine salt of nadifloxacin with improved bactericidal activity against MRSA as well as fluoroquinolone-resistant S. aureus by targeting bacterial DNA supercoiling enzymes DNA gyrase and topoisomerase IV. Levonadifloxacin displays a broad-spectrum bactericidal activity against Gram-positive and Gram-negative bacteria, atypical bacteria, anaerobic bacteria and bioterror pathogens with a very low frequency of mutation. Levonadifloxacin also displays improved activity under low pH biofilm environments. The drug has successfully completed phase I, phase II and phase III clinical trials in India. The U.S. Food and Drug Administration (FDA) granted a Qualified Infectious Disease Product (QIDP) designation to levonadifloxacin for the treatment of MRSA infections in August 2014.

Comparative toxicity assessment of nano- and bulk-phase titanium dioxide particles on the human mammary gland in vitro.

There is a major concern that exposure to titanium dioxide (TiO2) nanoparticles (NPs) can have degrading effects on human health as well as mammary gland because of the increased use in numerous sorts of nanotech-based health care and food merchandise. Also, there is a scarcity in NP toxicity studies on the mammary gland; therefore, the aim of the present study was to compare toxicity caused by nano- and bulk-phase TiO2 particles on the human mammary gland in vitro. In comparison to bulk-TiO2 particles, nano-TiO2 cause a significant (p < 0.05) reduction in viability and increased reactive oxygen species generation in the human mammary epithelial cells after a dose- (1, 2, 5, 10, 20, 50, and 100 µg/mL) and time (6, 12, 24, and 48 h)-dependent exposure. Further, an increase in genotoxicity in the mammary epithelial cells was observed as percent tail DNA and comet area was increased significantly (p < 0.05) at 12 h of exposure (10 and 100 µg/mL) with nano-TiO2. The scanning electron microscopic examination showed that a 50 µg/mL dose of both nano-TiO2 and bulk-TiO2 particles cause morphological changes and retarded growth pattern of mammary epithelial cells at 12 h. Moreover, a significant (p < 0.05) increase in apoptosis at 10 µg/mL and necrosis at 50 µg/mL concentrations of nano-TiO2 in comparison to bulk-TiO2 was observed in mammary epithelial cells. Finally, we can conclude that the toxicity caused by nano-TiO2 particles on the human mammary gland cells was comparatively higher than the bulk-TiO2 particles.

Postnatal distribution of ZnO nanoparticles to the breast milk through oral route and their risk assessment for breastfed rat offsprings.

Various studies in rodents have shown that nanoparticles are transferred to the breast milk. Under the present study, lactating Wistar rats were repetitively gavaged 5, 25, and 50 mg/kg bw of zinc oxide nanoparticles (ZnO-NPs) and 50 mg kg-1 bw of bulk zinc oxide (bZnO) for 19 days after parturition. The results showed that ZnO-NPs were absorbed in the small intestine of dams and distributed to the liver. Furthermore, ZnO-NPs were distributed to the intestine and liver of rat pups through dam's milk. No significant change in body weight was observed in the dams treated with ZnO-NPs or bZnO and their offsprings as compared to the control group. The spleen weight significantly increased in the rat dams treated with 50 mg kg-1 of ZnO-NPs. ZnO-NPs were mostly excreted through feces. The levels of liver cytochrome P450 reductase and serum total antioxidant capacity significantly decreased in the rat dams treated with ZnO-NPs (50 mg kg-1) and their offsprings. The levels of serum cytokines (tumor necrosis factor-alpha and interleukin-1 beta) and liver injury marker enzymes (alanine aminotransferase and aspartate aminotransferase) significantly increased in the rat dams treated with ZnO-NPs (25 and 50 mg kg-1) and their offsprings. The level of immunoglobulin A secretion in the intestinal fluid of rat dams and their offsprings is significantly increased by increasing the dose of ZnO-NPs. Histopathology of intestine and liver of offsprings whose rat dams were treated with ZnO-NPs (50 mg kg-1) showed gross pathological changes. These results provide information for the safety evaluation of ZnO-NPs use during lactation. In conclusion, a dose-dependent postnatal transfer of ZnO-NPs is hazardous to the breastfed offsprings.

Sarecycline hydrochloride for the treatment of acne vulgaris.

Sarecycline hydrochloride (Seysara) is a novel, narrow-spectrum tetracycline derivative approved by the U.S. Food and Drug Administration (FDA) in October 2018 for the treatment of inflammatory non-nodular moderate to severe acne vulgaris. It was initially developed by Paratek Pharmaceuticals, Inc. (U.S.) and Allergan plc (U.S.), which later was acquired by Almirall S.A. (Barcelona, Spain). Almirall S.A. obtained U.S. FDA approval of oral sarecycline tablets under the trade name Seysara. Sarecycline exhibits antibacterial activity against important skin/soft tissue pathogens with targeted activity against Cutibacterium acnes--an anaerobic Gram-positive bacterium linked with acne lesions--and also exerts anti-inflammatory effects as do other tetracyclines used in the treatment of acne vulgaris. Interestingly, unlike the broad-spectrum tetracyclines, sarecycline is less potent against aerobic Gram-negative bacilli and anaerobic bacteria associated with endogenous intestinal microbial flora. This provides it with a more specific antibacterial spectra with lower chances of adverse off-target antibacterial effects, thus making it a promising choice of treatment over others in its class. It has also demonstrated low propensity to resistance as compared with other tetracyclines and is also active against tetracycline-resistant Staphylococcus aureus as well as erythromycin- and clindamycin-resistant C. acnes strains. Sarecycline has successfully undergone numerous phase I, phase II and three phase III studies establishing it as a well-tolerated once-daily oral drug available as a tablet for the treatment of patients 9 years of age or above.

Management of multidrug-resistant tuberculosis in the 21st century.

The spread of drug-resistant tuberculosis (TB) continues to be a global health crisis with increasing cases of multidrug-resistant TB (MDR-TB) being diagnosed worldwide. The identification and clinical management of MDR-TB is associated with additional problems related to resistance, diagnosis and treatment as compared to drug-susceptible TB. Treatment of MDR-TB usually involves therapy with long regimens of second-line drugs up to 24 months resulting in higher risks of serious adverse effects, lack of compliance and heightened economic burden on the patients. Issues such as increasing transmission of drug-resistant strains, poor diagnostic coverage and lengthy, toxic treatments need to be overcome by innovative approaches such as quick diagnostic tools and shorter drug regimens as already recommended by the World Health Organization (WHO) in its 2018 Global Tuberculosis Report. This review highlights the challenges being faced by clinicians worldwide in the diagnosis and treatment of MDR-TB.

Delafloxacin meglumine for the treatment of acute bacterial skin and skin structure infections (ABSSSI).

Delafloxacin meglumine (Baxdela, WQ-3034, ABT-492, RX-3341; Melinta Therapeutics) was approved by the U.S. Food and Drug Administration (FDA) in June 2017 for the treatment of acute bacterial skin and skin structure infections on the basis of data from two phase III trials. Delafloxacin is a broad-spectrum anionic fluoroquinolone and its distinct chemical structure increases its potency in acidic environments. It is known to inhibit DNA replication and repair by targeting DNA gyrase and topoisomerase IV. Delafloxacin is administered via both oral and parenteral routes. It has potent activity against methicillin-resistant Staphylococcus aureus and Streptococci, and is also effective against Enterobacteriaceae and Pseudomonas aeruginosa. Delafloxacin is currently in phase III evaluation for treatment of community-acquired pneumonia and was classified as a qualified infectious disease product by the U.S. FDA in its approval.

Cartilage constructs engineered from chondrocytes overexpressing IGF-I improve the repair of osteochondral defects in a rabbit model.

Tissue engineering combined with gene therapy is a promising approach for promoting articular cartilage repair. Here, we tested the hypothesis that engineered cartilage with chondrocytes overexpressing a human insulin-like growth factor I (IGF-I) gene can enhance the repair of osteochondral defects, in a manner dependent on the duration of cultivation. Genetically modified chondrocytes were cultured on biodegradable polyglycolic acid scaffolds in dynamic flow rotating bioreactors for either 10 or 28 d. The resulting cartilaginous constructs were implanted into osteochondral defects in rabbit knee joints. After 28 weeks of in vivo implantation, immunoreactivity to ß-gal was detectable in the repair tissue of defects that received lacZ constructs. Engineered cartilaginous constructs based on IGF-I-overexpressing chondrocytes markedly improved osteochondral repair compared with control (lacZ) constructs. Moreover, IGF-I constructs cultivated for 28 d in vitro significantly promoted osteochondral repair vis-à-vis similar constructs cultivated for 10 d, leading to significantly decreased osteoarthritic changes in the cartilage adjacent to the defects. Hence, the combination of spatially defined overexpression of human IGF-I within a tissue-engineered construct and prolonged bioreactor cultivation resulted in most enhanced articular cartilage repair and reduction of osteoarthritic changes in the cartilage adjacent to the defect. Such genetically enhanced tissue engineering provides a versatile tool to evaluate potential therapeutic genes in vivo and to improve our comprehension of the development of the repair tissue within articular cartilage defects. Insights gained with additional exploration using this model may lead to more effective treatment options for acute cartilage defects.

Isolation and enrichment of type A spermatogonia from pre-pubertal buffalo ( Bubalus bubalis) testis.

The aim of this study was to isolate and subsequently enrich type A spermatogonia from pre-pubertal buffalo testis. Two-step enzymatic digestion was used to isolate spermatogonia from 10 to 14 months pre-pubertal buffalo calves, resulting in maximal release of spermatogonia from the seminiferous tubules. After enzymatic digestion, the type A spermatogonia were subsequently enriched by differential plating and Percoll gradient centrifugation. The identity of type A spermatogonia was determined by light microscopy and further characterised by Dolichos biflorus agglutinin, a specific marker for bovine type A spermatogonia by fluorescence-activated cell sorting analysis. After enzymatic isolation, the cell suspension contained about 27% of type A spermatogonia, which was enriched up to 71% with >70% cell viability. Further flow cytometric analysis showed the presence of THY1+ cells (cells expressing thymocyte differentiation antigen 1), suggesting that THY1 is a conserved marker of the undifferentiated spermatogonial cells in buffalo. The isolation of the enriched type A spermatogonia from buffalo testis opens ways to study the further biochemical characteristics of this important class of germ cells in this species.

Temporal and spatial migration pattern of the subchondral bone plate in a rabbit osteochondral defect model.

OBJECTIVE: Upward migration of the subchondral bone plate is associated with osteochondral repair. The aim of this study was to quantitatively monitor the sequence of subchondral bone plate advancement in a lapine model of spontaneous osteochondral repair over a 1-year period and to correlate these findings with articular cartilage repair. DESIGN: Standardized cylindrical osteochondral defects were created in the rabbit trochlear groove. Subchondral bone reconstitution patterns were identified at five time points. Migration of the subchondral bone plate and areas occupied by osseous repair tissue were determined by histomorphometrical analysis. Tidemark formation and overall cartilage repair were correlated with the histomorphometrical parameters of the subchondral bone. RESULTS: The subchondral bone reconstitution pattern was cylindrical at 3 weeks, infundibuliform at 6 weeks, plane at 4 and 6 months, and hypertrophic after 1 year. At this late time point, the osteochondral junction advanced 0.19 [95% confidence intervals (CI) 0.10-0.30] mm above its original level. Overall articular cartilage repair was significantly improved by 4 and 6 months but degraded after 1 year. Subchondral bone plate migration correlated with tidemark formation (r = 0.47; P < 0.0001), but not with the overall score of the repair cartilage (r = 0.11; P > 0.44). CONCLUSIONS: The subchondral bone plate is reconstituted in a distinct chronological order. The lack of correlation suggests that articular cartilage repair and subchondral bone reconstitution proceed at a different pace and that the advancement of the subchondral bone plate is not responsible for the diminished articular cartilage repair in this model.

Assessment of buffalo (Bubalus bubalis) sperm DNA fragmentation using a sperm chromatin dispersion test.

Chromosomal fragmentations or damage in sperm DNA has considerable value in determination of semen quality. However, rapid and/or simple method to assess sperm DNA integrity in buffalo has apparently not been reported. In the present study, SCD was used for the first time in buffalo bulls for assessment of sperm DNA fragmentation. A modified SCD protocol, under bright field microscope was developed and validated by comparison with other routine tests which can be used for processing of samples. The DNA fragmentation index (DFI) from SCD was correlated with semen quality parameters viz. viability (r=-0.68, p<0.05), membrane integrity (r=-0.74, p<0.05) and capacitation status (r=-0.69, p<0.05). The amount of DNA fragmentation assessed by SCD was highly correlated (R=0.874, p<0.05) with results of acridine orange test (AOT), a traditional method of assessing DNA damage. There were no significant differences between two observers with regards to scoring dispersion patterns. Therefore, the SCD test can be routinely used for detection of DNA fragmentation in buffalo sperm, with potential for replacing conventional time consuming tests.

Ultrasound guided transplantation of enriched and cryopreserved spermatogonial cell suspension in goats.

Spermatogonial stem cells transplantation provides a unique approach for studying spermatogenesis. Initially developed in mice, this technique has now been extended in farm animals and provides an alternative means to preserve valuable male germ line and to produce transgenic animals. The aim of this study was to enrich type A spermatogonial cells amongst the isolated cells from goat testis, to cryopreserve these enriched populations of cells and their subsequent transplantation in unrelated recipient goats under ultrasound guidance. The cells were isolated enzymatically and enriched by differential plating and separation on discontinuous percoll gradient. Ultrasound guided injection of trypan blue dye into rete testis resulted in 20-30% filling of the seminiferous tubules. Prior to transplantation, the cells were labelled with a fluorescent dye to trace donor cells in recipient seminiferous tubules after transplantation. The fluorescent-labelled cells were observed up to 12 weeks after transplantation.

Enhanced repair of articular cartilage defects in vivo by transplanted chondrocytes overexpressing insulin-like growth factor I (IGF-I).

Traumatic articular cartilage lesions have a limited capacity to heal. We tested the hypothesis that overexpression of a human insulin-like growth factor I (IGF-I) cDNA by transplanted articular chondrocytes enhances the repair of full-thickness (osteochondral) cartilage defects in vivo. Lapine articular chondrocytes were transfected with expression plasmid vectors containing the cDNA for the Escherichia coli lacZ gene or the human IGF-I gene and were encapsulated in alginate. The expression patterns of the transgenes in these implants were monitored in vitro for 36 days. Transfected allogeneic chondrocytes in alginate were transplanted into osteochondral defects in the trochlear groove of rabbits. At three and 14 weeks, the quality of articular cartilage repair was evaluated qualitatively and quantitatively. In vitro, IGF-I secretion by implants constructed from IGF-I-transfected chondrocytes and alginate was 123.2+/-22.3 ng/10(7) cells/24 h at day 4 post transfection and remained elevated at day 36, the longest time point evaluated. In vivo, transplantation of IGF-I implants improved articular cartilage repair and accelerated the formation of the subchondral bone at both time points compared to lacZ implants. The data indicate that allogeneic chondrocytes, transfected by a nonviral method and cultured in alginate, are able to secrete biologically relevant amounts of IGF-I over a prolonged period of time in vitro. The data further demonstrate that implantation of these composites into deep articular cartilage defects is sufficient to augment cartilage defect repair in vivo. These results suggest that therapeutic growth factor gene delivery using encapsulated and transplanted genetically modified chondrocytes may be applicable to sites of focal articular cartilage damage.

Antigens of goat spermatozoa that recognize homologous zona pellucida.

Goat sperm surface proteins obtained from purified plasma membrane (PPM) vesicles (purity of membrane checked by marker enzymes and transmission electron microscopy) were size fractionated on an fast protein liquid chromatography (FPLC) gel filtration column. All the seven surface proteins (129, 100, 46, 28, 27, 18 and 10 kDa) obtained were further fractionated and purified on high-efficiency gel filtration (GFC-HPLC) as well as ion exchange (DEAE-HPLC) columns. Antibodies were generated against the PPM and the protein fractions. Such resolved and purified surface antigens were tested by Dot Blot Immunoassay and homologous in vitro sperm-zona binding assays. It was revealed that the binding of goat spermatozoa to homologous zona pellucida was inhibited by antisera raised against the five lower molecular weight surface antigens. Further, the components of FPLC-AIII (46 kDa; A represents antigenic protein) and IV (28 kDa) were most promising as the antibodies against these fractions inhibited sperm binding to zona pellucida even at a dilution of 1 : 1000 as tested by the sperm-zona binding assays.

Molecular approaches for the evaluation of immune responses to zona pellucida (ZP) and development of second-generation ZP vaccines.

It has long been established that there are major variations in both the immunogenicity and antigenicity of native zona pellucida (ZP) proteins. These differences appear to be more pronounced with respect to genetically engineered ZP proteins, which do not have native post-translational modifications (for example glycosylation and sulphation). As the number of animal species that are now included in population management programmes using native porcine zona pellucida (PZP) proteins expands, it is increasingly important to carry out studies to evaluate the immune response variations among different species as well as the individual variation within a species. In an attempt to compare these complex immune responses, we have evaluated antibodies from numerous species immunized with native, genetically engineered ZP and synthetic ZP peptides. Such an immunocontraceptive method could have great potential. These studies are critical not only for the development of predictable immune responses that result in permanent sterilization versus reversible contraceptive effects, but also for predicting which vaccinogens (native ZP protein versus genetically engineered ZP proteins) might have detrimental effects on animal and human populations.

Capacitation and acrosome reaction in buffalo bull spermatozoa assessed by chlortetracycline and Pisum sativum agglutinin fluorescence assay.

Studies on buffalo sperm capacitation have been limited because of the non-availability of a direct assay system. We describe two methods for detecting the acrosomal status of buffalo spermatozoa, namely chlortetracycline (CTC) fluorescence assay and Pisum sativum agglutinin (FITC-PSA) stain. We also test them under various treatment regimens and simultaneously standardize and calibrate them with transmission electron microscopy. An initial comparison of three physiological media, such as Krebs-Ringer bicarbonate buffer, Tyrode solution and Brackett & Oliphant medium (having different calcium concentrations and osmolality) used for studying the capacitation of buffalo spermatozoa and assessed by CTC, FITC-PSA, Giemsa stain and TEM, revealed Brackett & Oliphant medium to be marginally better than the other two media. When stained with chlortetracycline, three distinct fluorescent patterns were visible in buffalo spermatozoa under capacitating conditions. These were 'F' with fluorescence in the post acrosomal region characteristic of uncapacitated acrosome-intact cells; 'B' with fluorescence on the anterior portion of the sperm head and a dark band in the post-acrosomal region, characteristic of capacitated, acrosome intact cells and 'AR' with a fluorescent band on the posterior portion of the head, characteristic of acrosome-reacted cells. The FITC-PSA intensely labels the acrosomal region of acrosome intact buffalo sperm. Acrosome reacted sperms had diminished acrosomal labelling by both the probes used. Buffalo spermatozoa was not capacitated when calcium was either omitted from the medium or chelated with EGTA. In the presence of Ca2+ ionophore, A23187, 68% at 4 h and 85% at 8 h completed the acrosome reaction. Time course studies revealed a 4 h incubation period at 1.71 mM Ca2+ concentration to be necessary before transformation of 'F' to 'B' cells could take place. Spontaneous acrosome reaction induced at 6 and 8 h incubation of buffalo spermatozoa in KRB medium resulted in conversion of 'B' cells to 'AR' cells while 'F' cells remained unchanged. A simultaneous evaluation of acrosome intact and acrosome-reacted cells using FITC-PSA, Giemsa and TEM gave results similar to examination by CTC stain. Both the assays are rapid, reproducible, reliable and they detect an increase or decrease in physiological acrosome reactions. They thus can be used to study effects of calcium and prove to be good monitoring systems to identify buffalo sperm capacitation and acrosome reaction in individual buffalo bulls for fertility studies.

Long-term results of KTP/532 laser uvulopalatopharyngoplasty.

The symptom of snoring is no longer one of humorous content and with the ever increasing awareness of its detriments, it has become even more important to find a treatment that would be immensely beneficial to the patient. We would like to present our experiences with the use of the KTP/532 Laser in performing the UP3. This study is significant as it presents a long term four year follow up of cases based on the patients' assessments. The technique itself is tailor made to suit the individual patient, ensuring optimal results which revealed that most patients i.e.; 84% were extremely pleased with the operation. The series also showed minimal morbidity and no intra or post-operative complications which reiterates the need for meticulous, atraumatic technique and judicious, discriminate selection of patients.

Surface protein changes in goat spermatozoa during capacitation.

Polypeptides of goat sperm surface before and after capacitation were examined by radiolabelling and immunologically using polyclonal antisera. Radioiodination revealed five protein bands having mol wt of 14.8, 72.4, 81, 100 and 128 kDa in uncapacitated ejaculated spermatozoa and only three bands of 23.4, 27 and 72.4 KDa in capacitated spermatozoa. The protein band with mol wt 72.4 kDa was only feebly iodinated in uncapacitated sperm surface but in capacitated spermatozoa it was heavily labelled. Western blot analysis of detergent-extracted proteins using gamma-globulin fraction of antisera raised against purified goat sperm plasma membrane revealed six antigens (17.8, 29.1, 33.4, 45.6, 85.1, 123.2 kDa) in uncapacitated spermatozoa, four (26, 32.1, 40.1, 45.6 kDa) in capacitated spermatozoa and only one (45.6 kDa) in acrosome-reacted spermatozoa. High mol wt proteins were more numerous on the surface of uncapacitated spermatozoa while the capacitated spermatozoa had relatively low mol wt proteins. An apparent effect of capacitation is the metabolism and reorganisation of proteins on goat sperm surface. Polypeptides on capacitated sperm surface revealed through radiolabelling and polyclonal antisera may have a likely receptor(s) role in the recognition and binding to homologous zona pellucida during fertilization.

Calcium requirement and time course of capacitation of goat spermatozoa assessed by chlortetracycline assay.

We standardized chlortetracycline fluorescent assay for studies of calcium requirement and time course of capacitation of goat spermatozoa. Three distinct fluorescent patterns were easily detected in goat spermatozoa incubated under capacitating conditions. Categorised according to nomenclature reported earlier, these are: 'F' with bright fluorescence in the postacrosomal region, characteristic of uncapacitated acrosomal-intact cells; 'B' with bright fluorescence on the anterior portion of the head and dark band in the postacrosomal region, characteristic of capacitated, acrosome-intact cells; 'AR' with lack of fluorescence on the head characteristic of acrosome-reacted cells. A close correspondence was observed when the results of CTC assay were compared with those obtained by transmission electron microscopy. Goat spermatozoa were not capacitated when calcium was omitted from the medium and 80% had CTC fluorescence of 'F' type. The size of 'B' cell population increased with increase in calcium concentration; at 1.0 mmol l-1 a peak representing 65-70% capacitated cells accumulated in 4 h. At higher concentrations, 'AR' cells were found along with 'B' cells and the two cell types were in equal proportions at 1.71 mmol l-1. Time course studies revealed a 2 h incubation period at 1.0 mmol l-1 and 1 h at 2 mmol l-1 calcium concentration before transformation of 'F' cells to 'B' cells was noticed. However, at no time were 'AR' cells found exclusively pointing to an equilibrium between the two sperm populations. Goat spermatozoa were also not capacitated when phosphate was omitted from the medium. Permeant anions (NO3-, SCN-), permeant weak acid (HCO3-) and organic phosphates (beta-glycerophosphate, glucose-6-phosphate) were unable to replace phosphate. The reason for their failure for the incidence of capacitation was traced to low uptake of calcium by goat spermatozoa. In the presence of phosphate, a 6-8-fold increase was measured over the calcium uptake when phosphate was omitted (2-4 nmol l-1 10(8) cells-1). Mersalyl inhibited the calcium uptake by goat spermatozoa as well as its capacitation most likely by inhibiting the calcium phosphate transporter located in the sperm plasma membrane.