Changes in Milk Protein Functionality at Low Temperatures and Rennet Concentrations.

This study aimed to evaluate the influence of low-concentration rennet on the chemical, rheological characteristics, and protein fractions of skim milk (SM) at 4 ± 1 °C. Skimmed milk (SM) was divided into four lots of 500 mL, and diluted rennet (1:10,000) was added at different levels at 4 ± 1 °C. The treatments included control (no rennet), T1 (0.001 mL/rennet), T2 (0.01 mL rennet), and T3 (0.1 mL rennet) treatments, which were incubated for 24 h. The sampling was performed at 0, 1, 2, 6, 12, and 24 h, and the SM after incubation time was heated to 73 °C/16 s to denature the rennet enzyme. Skim milk samples (SMS) (control and rennet-added samples) were evaluated for proximate composition, capillary gel electrophoresis (CGE), hydrodynamic diameter, zeta potential, and rheology at 0, 1, 2, 6, 12, and 24 h. Foaming ability, foaming stability, water-holding capacity (WHC), oil emulsifying activity (OEA), and emulsion stability (ES) were performed at 0, 12, and 24 h of incubation time. There was a significant (p < 0.05) increase in non-proteins by 0.50% and in non-casein nitrogen by 0.81% as incubation progressed. The results showed that aggregation or curd was not formed during storage time. The CGE data indicated that increasing the rennet concentration had a significant (p < 0.05) effect on decreasing κ-CN, and breakdown increased at higher levels of rennet usage. There was a significant (p < 0.05) increase in the hydrodynamic diameter and a decrease in the zeta potential values in rennet-added samples at the end of the incubation time (24 h). The rheological results showed no changes in the storage modulus (G'), loss modulus (G″), or viscosity values. Increasing the rennet amount and storage time led to a significant (p < 0.05) decrease in the foaming ability and foaming stability and a significant (p < 0.05) increase in the oil emulsifying activity and emulsion stability of rennet-added SMS. This study concluded that milk protein functionality can be changed without aggregating or curd formation, and rennet milk can be processed.

Abundance of selected genes implicated in testicular functions in Camelus dromedarius with high and low epididymal semen quality.

Studying testicular genes' expression may give key insights into precise regulation of its functions that influence epididymal sperm quality. The current study aimed to investigate the abundance of candidate genes involved in the regulation of testicular functions specially those regulate sperm function (PLA2G4D, SPP1, and CLUAP1), testicular steroidogenic function (ESR1 and AR), materials transport (AQP12B and LCN15), and defense mechanisms (DEFB110, GPX5, SOCS3, and IL6). Therefore, blood samples and testes with epididymis were collected from mature middle-aged (5-10 years) dromedary camels (n = 45) directly prior and after their slaughtering, respectively, during breeding season. Sera were evaluated for testosterone level and testicular biometry was measured with caliper. The epididymal tail semen was evaluated manually. Samples were distinguished based on testosterone level, testicular biometry, as well as epididymal semen features into high and low fertile groups. Total RNA was isolated from testicular tissues and gene expression was done using Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results revealed that testosterone levels were significantly (P < 0.005) higher in camels with good semen quality than those of low quality. There was a significant (P < 0.0001) increase in testicular weight, length, width, thickness, and volume in high fertile than low fertile camels. PLA2G4D, SPP1, CLUAP1, ESR1, AR, AQP12B, LCN15, DEFB110, GPX5, and SOCS3 genes were upregulated (P < 0.001), and IL6 gene was downregulated (P < 0.01) in the testes of high fertile camels compared to the low fertile one. Thus, it could be concluded that examined genes might be valuable monitors of testicular functional status and fertility in dromedary camels.

A scalable overexpression of a thermostable recombinant poly-histidine tag carboxyl esterase under lambda promoter: purification, characterization, and protein modelling.

BACKGROUND: As a white biotechnological trend, esterases are thought to be among the most active enzymes' classes in biocatalysis and synthesis of industrially importance organic compounds. Esterases are used in many applications such as the manufacture of pharmaceuticals, cosmetics, leather, textile, paper, food, dairy products, detergents, and treatment of some environmental pollutants. RESULTS: A poly-histidine moiety was added to the C-terminal end of the Geobacillus sp. gene encoding carboxyl esterase (EstB, ac: KJ735452) to facilitate one-step purification. This recombinant protein was successfully expressed in Escherichia coli (E. coli) under control of Lambda promoter (λ). An open reading frame (ORF) of 1500 bps encoding a polypeptide of 499 amino acid residues and a calculated molecular weight (54.7 kD) was identified as carboxyl-esterase B due to its conserved glycine-X-serine-X-glycine motif (G-X-S-X-G) and its high similarity toward other carboxyl esterases, where the 3-D tertiary structure of EstB was determined based on high homology % (94.8) to Est55. The expression was scaled up using 7-L stirred tank bioreactor, where a maximum yield of enzyme was obtained after 3.5 h with SEA 51.76 U/mg protein. The expressed protein was purified until unity using immobilized metal affinity chromatography (IMAC) charged with cobalt and then characterized. The purified enzyme was most active at pH 8.0 and remarkably stable at pH (8-10). Temperature optimum was recorded at 65 °C, and it kept 70% of its activity after 1-h exposure to 60 °C. The active half-live of enzyme was 25 min at 70 °C and a calculated T melting (Tm) at 70 °C. The determined reaction kinetics Michaelis-Menten constant (Km), maximum velocity rate (Vmax), the turnover number (Kcat), and catalytic efficiency (Kcat/Km) of the pure enzyme were found 22.756 mM, 164.47 U/ml (59.6 min-1), and (2.619 mol/ min), respectively. CONCLUSION: Creation of a recombinant 6 × -His estB derived from a thermophile Geobacillus sp. was performed successfully and then overexpressed under λ-promoter. In a bench scale bioreactor, the overexpression was grown up, followed by one-step purification and biochemical characterization. The recorded promising pH and temperature stability properties suggest that this expressed carboxyl esterase could be used in many industrial sectors.

Targeted memory reactivation in human REM sleep elicits detectable reactivation.

It is now well established that memories can reactivate during non-rapid eye movement (non-REM) sleep, but the question of whether equivalent reactivation can be detected in rapid eye movement (REM) sleep is hotly debated. To examine this, we used a technique called targeted memory reactivation (TMR) in which sounds are paired with learned material in wake, and then re-presented in subsequent sleep, in this case REM, to trigger reactivation. We then used machine learning classifiers to identify reactivation of task-related motor imagery from wake in REM sleep. Interestingly, the strength of measured reactivation positively predicted overnight performance improvement. These findings provide the first evidence for memory reactivation in human REM sleep after TMR that is directly related to brain activity during wakeful task performance.

Sleep is crucial for rest and recovery, but it also allows the brain to process things it has learned while awake. This is why a person may go to bed frustrated with learning a tune on the piano but wake up the next morning ready to play it without fumbling. For this to happen, it is thought that memories must be reactivated during sleep ­ something which can be studied by monitoring brain activity. While it has been shown that memory reactivation occurs in some stages of human sleep, it was unclear whether it occurred in a specific stage known as REM sleep ­ which is important for learning. To study memory reactivation during REM sleep, Abdellahi et al. recruited volunteers and monitored their brain activity during an 'adaptation night' when certain sounds played as they slept. The following day, memories ­ such as an image or pressing a certain button ­ were paired with the sounds, which were replayed during REM sleep the following night to trigger memory reactivation (experimental night). Abdellahi et al. measured how strongly brain activity during each night related to the waking activity when the sound pairing tasks were imagined and compared the adaptation and experimental nights. The experimental night showed clear signs of memory reactivation after the sounds were played during REM sleep, suggesting that the sounds triggered memories of the associated images or buttons. These findings show that in humans, brain activity patterns that indicate memory reactivation can be identified during REM sleep. The work paves the way for future studies into the characteristics of this memory reactivation and how to trigger it in a way that leads to improvements in memory.

Targeting targeted memory reactivation: Characteristics of cued reactivation in sleep.

Targeted memory reactivation (TMR) is a technique in which sensory cues associated with memories during wake are used to trigger memory reactivation during subsequent sleep. The characteristics of such cued reactivation, and the optimal placement of TMR cues, remain to be determined. We built an EEG classification pipeline that discriminated reactivation of right- and left-handed movements and found that cues which fall on the up-going transition of the slow oscillation (SO) are more likely to elicit a classifiable reactivation. We also used a novel machine learning pipeline to predict the likelihood of eliciting a classifiable reactivation after each TMR cue using the presence of spindles and features of SOs. Finally, we found that reactivations occurred either immediately after the cue or one second later. These findings greatly extend our understanding of memory reactivation and pave the way for development of wearable technologies to efficiently enhance memory through cueing in sleep.

A sustainable and effective bioprocessing approach for improvement of acid phosphatase production and rock phosphate solubilization by Bacillus haynesii strain ACP1.

There is indeed a tremendous increase in biotechnological production on a global scale, more and more innovative bioprocesses, therefore, require to perform ideally not only in a small lab- but also on large production scales. Efficient microbial process optimization is a significant challenge when accomplishing a variety of sustainable development and bioengineering application objectives. In Egypt's mines, several distinct types of rock phosphate (RP) are utilized as a source of phosphate fertilizers in agriculture. It is more ecologically beneficial to utilize RP bio-solubilization than acidulation. Therefore, this work aimed to strategically scale up the acid phosphatase (ACP) production and RP bio-solubilization by the newly-discovered Bacillus haynesii. The use of consecutive statistical experimental approaches of Plackett-Burman Design (PBD), and Rotatable Central Composite Design (RCCD), followed by pH-uncontrolled cultivation conditions in a 7 L bench-top bioreactor revealed an innovative medium formulation. These approaches substantially improved ACP production, reaching 207.6 U L-1 with an ACP yield coefficient Yp/x of 25.2 and a specific growth rate (µ) of 0.07 h-1. The metals Na, Li, and Mn were the most efficiently released from RP during the solubilization process by B. haynesii. The uncontrolled pH culture condition is the most suitable setting for simultaneously improving the ACP and organic acids production. The most abundant organic acid produced through the cultivation process was lactic acid, followed by glutamic acid and hydroxybenzoic acid isomer. The findings of TGA, DSC, SEM, EDS, FTIR, and XRD analysis emphasize the significant influence of organic acids and ACP activity on the solubilization of RP particles.

Long term effects of cueing procedural memory reactivation during NREM sleep.

Targeted memory reactivation (TMR) has recently emerged as a promising tool to manipulate and study the sleeping brain. Although the technique is developing rapidly, only a few studies have examined how the effects of TMR develop over time. Here, we use a bimanual serial reaction time task (SRTT) to investigate whether the difference between the cued and un-cued sequence of button presses persists long-term. We further explore the relationship between the TMR benefit and sleep spindles, as well as their coupling with slow oscillations. Our behavioural analysis shows better performance for the dominant hand. Importantly, there was a strong effect of TMR, with improved performance on the cued sequence after sleep. Closer examination revealed a significant benefit of TMR at 10 days post-encoding, but not 24 h or 6 weeks post-encoding. Time spent in stage 2, but not stage 3, of NREM sleep predicted cueing benefit. We also found a significant increase in spindle density and SO-spindle coupling during the cue period, when compared to the no-cue period. Together, our results demonstrate that TMR effects evolve over several weeks post-cueing, as well as emphasising the importance of stage 2, spindles and the SO-spindle coupling in procedural memory consolidation.

Targeted memory reactivation in REM but not SWS selectively reduces arousal responses.

A growing body of evidence suggests that sleep can help to decouple the memory of emotional experiences from their associated affective charge. This process is thought to rely on the spontaneous reactivation of emotional memories during sleep, though it is still unclear which sleep stage is optimal for such reactivation. We examined this question by explicitly manipulating memory reactivation in both rapid-eye movement sleep (REM) and slow-wave sleep (SWS) using targeted memory reactivation (TMR) and testing the impact of this manipulation on habituation of subjective arousal responses across a night. Our results show that TMR during REM, but not SWS significantly decreased subjective arousal, and this effect is driven by the more negative stimuli. These results support one aspect of the sleep to forget, sleep to remember (SFSR) hypothesis which proposes that emotional memory reactivation during REM sleep underlies sleep-dependent habituation.

Expression of calbindin-D9k and vitamin D receptor in the uterus of Egyptian buffalo during follicular and luteal phases.

Uteri of mature Egyptian buffalo cows (5-10 years old) were collected at follicular (n=12) and luteal (n=16) phases of estrous cycle to investigate the expression of calbindin-D9k (CaPB-9k) and vitamin D receptor (VDR). This study was done using avidin-biotin immunohistochemistry method. In addition, blood levels of calcium (Ca), vitamin D3 (Vit D), estrogen (E2) and progesterone (P4) were measured. The immunohistochemical findings restricted the expressions of CaBP-9k and VDR to the luminal and glandular epithelia of the endometrium implicating the importance of CaBP-9K and VDR in the function of endometrial epithelium, especially the glandular one, in order to prepare a receptive uterus. On the other hand, the myometrium did not express CaBP-9k or VDR that denies the potential role of CaBP-9k and VDR in the uterine contractility during the estrous cycle of Egyptian buffalo. All of Ca, Vit D, and P4 blood levels significantly (P<0.05) increased during luteal phase however, blood level of E2 significantly (P<0.05) increased during follicular phase. The expressions of CaBP-9k and VDR in the uterus of Egyptian buffalo were significantly (P<0.05) higher during luteal (P4 dominant) phase than during the follicular (E2 dominant) phase indicating that P4 up-regulates the expressions of CaBP-9k and VDR. In view of these observations, this study represents the first characterization of CaBP-9K and VDR expression in the uterus of Egyptian buffalo and suggests the pivotal role of CaBP-9k and VDR in the uterine receptivity. Furthermore, it demonstrates the regulatory role of P4 for expressions of CaBP-9k and VDR in buffalo uterus.

Photolysis degradation of polyaromatic hydrocarbons (PAHs) on surface sandy soil.

Polycyclic aromatic hydrocarbons (PAHs) are potent environmental pollutants, and some of them have been identified as carcinogenic and mutagenic. To advance the knowledge of the environmental fate of PAHs, we systematically investigated the influence of different UV wavelengths irradiation on photolysis of PAHs on sandy soil under tow wavelengths (254 and 306 nm) UV irradiation for six PAHs. In addition, kinetic model and influence of several parameters on PAHs photolysis have been studied. The results obtained indicated that UV radiation with a wavelength of 306 nm was more efficient in the photolysis of the polycyclic aromatic hydrocarbons. Our results showed that fluoranthene (Flt) was the fastest in decomposition, has the greatest value for the coefficient of photolysis (7.4 × 10(-3) h(-1)), and has less half-life, reaching 94 h when using a wavelength of 254 nm. The results indicated that the pyrene (Pyr) was more resistant to photolysis in comparison with indeno(1,2,3-cd) pyrene (IP) and fluoranthene (Flt). The results indicate that photolysis is a successful way to remediate the six studied PAHs compounds.

Follicular turnover and hormonal association in postpartum goats during early and late lactation.

To clarify the effect of lactation period on ovarian follicular activity and associated hormonal levels in goats, six goats were monitored daily by ultrasonographic examination with blood sampling during early (Days 5 to 25; Day 0 was the day of kidding) and late (Days 40 to 60) lactation. While the presence of a corpus luteum of pregnancy retarded follicular growth in the ipsilateral ovary until Days 11-13 postpartum, the total follicular number (TFN) and area (TFA) increased during late lactation due to the significant increase in the number of medium- and large-sized follicles and decrease in the number of small follicles. Four goats showed a similar pattern of follicular development during the period studied characterized by the emergence of five and six waves during the early and late lactation, respectively. The largest follicle diameter of the first three waves monitored during early lactation was significantly smaller as compared with the diameter of those existing during late lactation. TFN showed a positive correlation with FSH but showed a negative correlation with immunoreactive (ir-) inhibin and estradiol during the postpartum period. TFA was positively correlated with ir-inhibin, estradiol and PRL and negatively correlated with FSH during the monitored periods. The plasma levels of ir-inhibin and progesterone were significantly higher during late lactation compared with the levels recorded during early lactation. Ir-inhibin levels showed a significant positive correlation with LH and estradiol during early and late lactation but showed a negative correlation with FSH during the whole lactation period. LH was positively correlated with estradiol and PRL during early and late lactation, respectively. These results suggest that the lactation period has a detrimental effect on ovarian activity during the early postpartum period in goats.

Evidence of melatonin synthesis in the cumulus oocyte complexes and its role in enhancing oocyte maturation in vitro in cattle.

Melatonin is a multifunctional molecule that mediates several circadian and seasonal reproductive processes. The exact role of melatonin in modulating reproduction, however, is not fully understood-especially its effects on the ovarian follicles and oocytes. This study was conducted to investigate the expressions of the ASMT and melatonin-receptor MTNR1A and MTNR1B genes in bovine oocytes and their cumulus cells, as well as the effects of melatonin on oocyte nuclear and cytoplasmic maturation in vitro. Cumulus-oocyte complexes (COCs) from abattoir ovaries were cultured in TCM-199 supplemented with melatonin at concentrations of 0, 10, 50, and 100 ng/ml. The expression of ASMT, MTNR1A, and MTNR1B genes was evaluated by RT-PCR. Moreover, the effects of melatonin on cumulus cell expansion, nuclear maturation, mitochondrial characteristics and COCs steroidogenesis were investigated. Furthermore, the level of reactive oxygen species (ROS) was evaluated in denuded oocytes. Our study revealed that ASMT and MTNR1A genes were expressed in COCs, while the MTNR1B gene was expressed only in oocytes. Additionally, melatonin supplementation at 10 and 50 ng/ml to in vitro maturation medium significantly enhanced oocyte nuclear maturation, cumulus cell expansion and altered the mitochondrial distribution patterns, but had no effects on oocyte mitochondrial activity and COCs steroidogenesis. Melatonin-treated oocytes had a significantly lower level of ROS than controls. The presence of melatonin receptors in COCs and its promoting effects on oocyte nuclear and cytoplasmic events, indicate the potentially important roles of this hormone in regulating bovine oocyte maturation. Moreover, the presence of ASMT transcript in COCs suggests the possible involvement of these cells in melatonin biosynthesis.

Ovarian follicular dynamics and hormonal changes in goats during early pregnancy.

The present study was conducted to characterize follicular development and its hormonal control during early pregnancy in goats. The ovaries of goats (n=8) were scanned daily for follicles (> or = 2 mm in diameter) and corpora lutea by transrectal ultrasound with blood sampling from the jugular vein for monitoring the hormonal changes during the first thirty-five days after mating. During early pregnancy, three (37.5%), four (50%) and one (12.5%) goat showed nine, eight and seven waves of follicular development, respectively. The corpora lutea were detected as early as Day 3.61 ± 0.45 (7.47 ± 0.43 mm) of pregnancy (Day 0=day of mating) and attained their maximal cross-sectional diameter (10.64 ± 0.37 mm) on Day 25.7 ± 0.8 of pregnancy, respectively. A transient rise in FSH levels was temporally associated with the day of follicular wave emergence (up to three days prior to wave emergence). The plasma LH and estradiol levels were negatively correlated with the progesterone concentration. The rise in plasma immunoreactive (ir) inhibin levels was negatively correlated with the FSH concentration and positively correlated with the number of large-sized follicles. Alternatively, the mean plasma ir-inhibin levels showed a noticeable decline with the progression of pregnancy. The present results demonstrated that follicular development during early pregnancy shows a wave-like pattern, with seven to nine waves developing until Day 35 after breeding, and that the number of follicular waves can be predicted by the number of FSH peaks. The current study also demonstrated that the role of inhibin as an FSH regulator is maintained throughout early pregnancy.

Profiles of circulating steroid hormones, gonadotropins, immunoreactive inhibin and prolactin during pregnancy in goats and immunolocalization of inhibin subunits, steroidogenic enzymes and prolactin in the corpus luteum and placenta.

The current study was performed to follow up the circulating hormonal changes and to correlate the findings with the physiological activity of the corpus luteum (CL) and placenta during pregnancy in goats. Blood samples were collected weekly from five goats during pregnancy for measuring steroid and protein hormones. A gradual increase was observed in immunoreactive (ir-) inhibin, with maximal levels at the 17th week. The plasma concentrations of estradiol and prolactin (PRL) showed nearly similar patterns during pregnancy, where they declined to basal levels during the first 4 weeks post-breeding and then increased significantly, with the maximal concentration during late pregnancy. The plasma FSH and LH concentrations were maintained at basal levels throughout the gestation period. The plasma progesterone concentration abruptly increased in the first week post-breeding and remained at high values throughout the pregnancy period. Immunohistochemical localization of inhibin alpha, beta(A), beta(B) and steroidogenic enzymes cytochrome P450 aromatase, 3alpha-hydroxysteroid dehydrogenase (3betaHSD), cytochrome 17alpha-hydroxylase P450 and cholesterol side-chain cleavage cytochrome P450 in the cyclic and pregnant goat CL revealed positive immunoreactivity without affinity differences between the luteal and pregnancy stages. The placental syncytiotrophoblasts also showed positive staining, except for inhibin beta(A) and 3betaHSD. The giant binucleate cells of the placenta showed positive immunoreactions to PRL. These results suggest that the high concentrations of ir-inhibin, estradiol and PRL during late pregnancy are of placental origin and that the placenta may have a vital role in the maintenance of pregnancy, regulation of mammary growth and preparation for kidding and lactation in goats.

Increasing bioavailability of silymarin using a buccal liposomal delivery system: preparation and experimental design investigation.

Silymarin is a natural lipotropic agent of low bioavailability from oral products. The aim of our study is to prepare buccal liposomal delivery system of silymarin with higher bioavailability. The effect of lecithin:cholesterol molar ratio on the percentage drug encapsulated was investigated. The influence of fluctuating the amount of added drug was also determined. The effect of additives such as positive charge inducer, negative charge inducer and surfactants was studied using two different 2(3) full factorial designs. Furthermore, additives used to optimize liposomal product were also investigated for their optimal concentrations, release properties and in vitro permeation and absorption through chicken cheek pouch. Optimal liposomal encapsulation efficiency was found at 7:4 lecithin to cholesterol molar ratio. A decrease in entrapment efficiency with increasing cholesterol content was observed. Tween 20 or Tween 80 beyond 0.5 molar ratio decreased the entrapment efficiency. Positively charged liposomes showed superior entrapment efficiency over neutral and negatively charged liposomes. Release studies as well as permeation and absorption studies showed that hybrid liposomes prepared according to formula 3 containing lecithin, cholesterol, stearyl amine and Tween 20 in 9:1:1:0.5 molar ratio, respectively, gave the best drug absorption and permeation. It showed steady state permeation through chicken cheek pouch for 6h. This is expected to improve the bioavailability of silymarin in the developed liposomal buccal delivery system, as the results show an increase in drug penetration compared to free drug powder.

Antichlamydial activity of vaginal secretion.

OBJECTIVE: The purpose of this study was to investigate the possible antichlamydial activity of vaginal secretion and to partially characterize the inhibitory principle. STUDY DESIGN: Vaginal secretions obtained from 156 women attending a family planning or gynecologic outpatient clinic for contraceptive advice were studied for the influence on the inclusion formation of Chlamydia trachomatis in cycloheximide-treated McCoy cell cultures. RESULTS: Vaginal secretions from 156 women inhibited the inclusion formation of Chlamydia trachomatis. The inhibition was concentration dependent and the inhibitory principle had a molecular weight of < 10,000 d. It was heat labile. It was not related to antichlamydial antibodies in vaginal secretions. Only three (2%) of the women had a positive culture for Chlamydia trachomatis. Three had immunoglobulin A and three had immunoglobulin G antichlamydial antibodies in vaginal secretions. Secretions of those with a vaginal pH of 3.5 to 4.5 decreased the chlamydial inclusion count by 75% compared with controls. The corresponding percentage for those with a pH of 5.0 to 6.0 was 48% and for those with pH > 6 was 33%. Vaginal secretions of oral contraceptive users and nonusers did not differ in the capacity to decrease the chlamydial inclusion count, p > 0.01. CONCLUSIONS: When vaginal secretions were added to McCoy cell cultures infected by Chlamydia trachomatis, the chlamydia inclusion number decreased. There was a correlation between pH of the vaginal secretion and the inhibitory principle. Oral contraceptive use had no influence on the inhibition.

Antichlamydial activity of cervical secretion in different phases of the menstrual cycle and influence of hormonal contraceptives.

Cervical secretion from three groups of asymptomatic women, either being oral contraceptive (OC) non-users or users (ethinylestradiol plus desogestrel or levonorgestrel), was tested for its capacity to prevent Chlamydia trachomatis, serotype I, from forming inclusions in cycloheximide-treated McCoy cells. The non-user groups were comprised of 12 women from whom cervical secretion was collected twice weekly during the menstrual cycle and 15 women from whom cervical secretion was collected once or twice weekly. The OC users included 66 women from whom cervical secretion was collected once or twice during their menstrual cycle. Cervical secretion from the non-users produced a decrease in the chlamydial inclusion count by 70%-90% during the first 3 weeks of the menstrual cycle, as compared with the fourth and fifth week when the reduction was 56%-68% (p < 0.001). Secretion from the OC users showed a more effective decrease in the inclusion count during the first 3 weeks of the menstrual cycle, as compared with samples obtained at the fourth and fifth weeks, i.e. 15%-35% vs. 20%-25% (p < 0.001). Cervical secretion of the non-users as compared to the users produced a significant decrease in the inclusion count, viz. 70%-90% vs. 15%-35% (p < 0.001) during the first 3 weeks as compared with 56%-68% vs. 20%-25% (p < 0.001) in the fourth or fifth week. The study suggests that natural resistance to genital chlamydial infection can differ during the menstrual cycle and it may be influenced by oral contraceptive use.

Antichlamydial activity of lacrimal fluid in patients with trachoma.

The effect of lacrimal fluid on the growth of Chlamydia trachomatis in cycloheximide-treated McCoy cells was studied in 172 persons with active trachoma (Group A), in 54 with scarring trachoma (Group B) and in 40 healthy subjects (Group C). The patients in groups A and B were treated with tetracycline eye ointment for 4-6 weeks after which tears were collected for retesting. Pooled lacrimal fluid from patients with active trachoma, collected before treatment, had a higher antichlamydial activity compared with healthy individuals. No reduction of the chlamydial inclusion count was seen with such fluid from patients with scarring trachoma. After tetracycline treatment, patients with active trachoma had a slight decrease in their inhibitory activity. In patients with scarring trachoma, the treatment did not significantly reduce the inclusion count. Antichlamydial antibodies were detected more often in patients with active trachoma than in patients with scarring trachoma, while the healthy individuals had no such antibodies. Ultrafiltered and nonfiltered lacrimal fluids were equally effective in inhibiting C. trachomatis inclusion-formation. The inhibitory principle had a molecular weight of less than 10,000 Da.

Prevalence of trachoma among displaced persons in the Sudan: a clinical and sero-epidemiological study.

The prevalence of trachoma was determined among displaced persons from the north, west and south of The Sudan who had settled in Angola Village, Omdurman County. Of 616 persons examined, 376 (61%) were found to have clinical signs of active trachoma. Of the 448 children, aged 4 months to 15 years, 55 (12%) had mild, 69 (15%) moderately severe, and 210 (47%) severe disease. The corresponding figures for those aged 16 and older (adults) were 5 (3%), 12 (7%) and 25 (15%), respectively. The prevalence of active trachoma among the children in the village was 75%, being higher among those from southern (86%) Sudan than for those from the northern (64%) and western (66%) regions. The corresponding figures for the adults were 25%, 38%, 13% and 14%. Antibodies to Chlamydia trachomatis were found in the lacrymal fluid of 224 (67%) and in the serum of 272 (81%) of the children tested. A higher (74%) prevalence rate of antibody-positive tears was found in children from the south than from either northern (58%) or western (61%) Sudan. The corresponding percentages of antibody-positive sera were 90%, 72% and 73%. In the adults, antibodies to C. trachomatis were found in tears of 28 (67%). As in the children, the proportion of adults with antibody-positive tears was higher among those from the south (80%) than in those from north or west Sudan (25% and 38%, respectively). This was also true of the prevalence of serum antibodies, which was 93% versus 75% and 75%, respectively. Trachoma is still common in The Sudan among persons of low socio-economic status.(ABSTRACT TRUNCATED AT 250 WORDS)