Search

Abnormalities in the morphology of the corpus callosum have been found to be involved in cognitive impairments or abnormal behaviour in patients with mental disorders such as schizophrenia and bipolar disorder. The present study investigated morphological shape differences of the corpus callosum in a large cohort of 223 participants between normal, schizophrenic and bipolar patients on MRI scans, CT scans and cadaver samples. Healthy samples were compared to a mental disorder population sample to determine morphological shapes variations associated with schizophrenia and bipolar disorder. Landmark-based methodology was used to contour the corpus callosum shape that served as standard positions to allow for radial and thickness partitioning in order to determine shape variations within the specific localised anatomical sections of the corpus callosum. Shape analysis was performed using Ordinary Procrustes averaging and superimposing landmarks to define an average landmark position for the specific regions of the corpus callosum. No significant global shape differences were found between the different mental disorders. Schizophrenia and bipolar shapes differed mostly in the genu-rostrum, posterior body, isthmus and splenium. Sample group comparisons yielded significant differences between all groups and global measurement parameters and in various sub-regions. The findings of the present study suggest that the corpus callosum in schizophrenia and bipolar differs significantly compared to healthy controls, specifically in the anterior body and isthmus for schizophrenia and only in the isthmus for bipolar disorder. Shape changes in these regions may possibly, in part, be responsible for the symptoms and cognitive impairments observed in schizophrenia and bipolar disorder., (© 2022 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.)

Purpose: To determine whether femoral epicondylar width (FECW) obtained from either magnetic resonance imaging (MRI) or plain radiographs could be used to predict anterior cruciate ligament (ACL) length. A secondary purpose was to develop a formula to use maximum FECW on either MRI or plain radiographs to estimate ACL length preoperatively., Methods: The MRIs and radiographs of 40 patients (mean age 41.0 years), with no apparent knee pathology, surgery, or trauma were included. The ACL length was measured on MRI followed by FECW on both MRI and radiograph of the same patient. This allowed the development of equations able to predict ACL length according to the FECW measured on either an MRI or radiograph., Results: The mean ACL length was 40.6 ± 3.6 mm. FECW measured on both MRIs and radiographs was sufficient to predict ACL length. Pearson's correlations revealed a high positive relationship between ACL length and FECW on MRI (r = 0.89, P < .0001) and ACL length and FECW on radiograph (r = 0.83, P < .0001). The coefficient of determination (R 2 ) was calculated to be MRI: R 2  = 0.78 and radiograph: R 2  = 0.68 and confirmed that FECW measured on both MRI and radiograph were sufficient to predict ACL length. Based on these models, ACL length can be predicted by FECW using the following formulas: MRI: ACL length = 0.47 (FECW) + 1.93 and radiograph: ACL length = 0.31 (FECW) + 11.33., Conclusions: This study demonstrated that FECW measured on either MRI or anteroposterior radiograph could reliably estimate ACL length on a sagittal MRI. There was a high positive relationship between ACL length and FECW on both MRI and radiographs, although MRIs do predict ACL length more reliably., Clinical Relevance: Preoperative ACL length assessment, using FECW on MRI or radiograph, is useful in graft selection and in preventing inadequate graft harvesting for ACL reconstruction, especially if an individualized anatomical approach is pursued., (© 2019 by the Arthroscopy Association of North America. Published by Elsevier Inc.)

Introduction: Mixed gender basic military training (BMT) is adopted to integrate the female South African soldier into the military. This study aimed to assess gender differences before, during (12 weeks), and after a 20-week mixed BMT course and determine if BMT significantly reduced these differences., Methods: A total of 186 soldiers (114 male: mean age = 21.0 ± 1.1 year; 72 female: mean age = 20.5 ± 1.2 year) completed the BMT course and all anthropometric, physical fitness, explosive power, and hand grip strength measurements. Repeated-measures analysis of variance was used to model BMT data with main effects for gender comparison between males and females, and time main effect for evaluation of differences between weeks 1, 12, and 20 of BMT, as well as an interaction effect for differences in changes over time for males and females. Alpha was set at α ≤0.05., Results: Male soldiers were significantly taller (p < 0.001) and scored better in all measurements at the start of BMT, differences ranged from 1.6% to 50% between genders. Differences narrowed by up to 18.5% in aerobic, push-up, abdominal measurements, and to 4.6% in the South African National Defense Force fitness test. Differences in power output and hand grip strength remained unchanged., Conclusion: Large initial anthropometrical and physical fitness differences decreased but were still obvious at the end of BMT. BMT should bridge the physical gap between male and female soldiers to ensure they can all perform the same duties. The enforcing of equal minimum physical fitness requirements for acceptance into BMT; conditional acceptance into the military subject to the successful completion of a bridging course aimed at improving physical fitness in individuals who do not meet the minimum physical fitness requirements for acceptance; and developing a cyclic physical training program with different entry points, dependent on initial physical performance at the start of BMT, ensuring adequate progression and overload for all soldiers are possible avenues to explore to achieve this goal., (Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.)

Grant, CC, Mongwe, L, Janse van Rensburg, DC, Fletcher, L, Wood, PS, Terblanche, E, and du Toit, PJ. The difference between exercise-induced autonomic and fitness changes measured after 12 and 20 weeks of medium-to-high intensity military training. J Strength Cond Res 30(9): 2453-2459, 2016-The aim of this study was to compare the physical fitness, based on VO2max and exercise-induced cardiac autonomic changes, measured by heart rate variability (HRV) of 12 weeks with 20 weeks of training in the South African National Defence Force. Recruits (n = 154) participated in a medium-to-high intensity exercise intervention (daily energy expenditure: 8,485 kJ·d). The significant effect on VO2max between weeks 1 and 12 (48.57, SD = 9.25 vs. 53.36, SD = 7.21] did not continue during weeks 12-20 (53.36, SD = 7.21 vs. 53.87, SD = 7.87). No changes in the supine low frequency (LF)/high frequency (HF) (0.48, SD = 0.51 vs. 0.41, SD = 0.64) or the standing LF/HF (4.02, SD = 5.14 vs. 3.91, SD = 5.28), an indicator of autonomic balance and a possible indicator of overtraining syndrome, suggests that overtraining did not take place during weeks 12-20. This was confirmed with further decreases in supine and standing heart rate. However, the power of the vagal-induced variability continued to increase after 12 weeks. Increased vagal influence without concurrent change in autonomic balance may be interpreted as decreased sympathetic cardiac control. It is important to note that although no fitness changes were detected, positive cardiac autonomic conditioning did continue between weeks 12 and 20, as measured by increased vagal-induced HRV and decreased sympathetic influence on cardiac control. Results may be extrapolated to training in the normal population/athletes after a medium-to-high intensity exercise program, as this intervention was a closely monitored and standardized exercise program.

We have demonstrated simultaneous laser frequency stabilization of a UV and IR laser, to coupled transitions of ions in the same spectroscopic sample, by detecting only the absorption of the UV laser. Separate signals for locking the different lasers are obtained by modulating each laser at a different frequency and using lock-in detection of a single photodiode signal. Experimentally, we simultaneously lock a 369 nm and a 935 nm laser to the (2)S(1/2) → (2)(P(1/2) and (2)D(3/2) → (3)D([3/2]1/2) transitions, respectively, of Yb(+) ions generated in a hollow cathode discharge lamp. Stabilized lasers at these frequencies are required for cooling and trapping Yb(+) ions, used in quantum information and in high precision metrology experiments. This technique should be readily applicable to other ion and neutral atom systems requiring multiple stabilized lasers.

The effects of 20 microg/ml exogenous arachidonic acid (AA) and prostaglandin A(2) (PGA(2)) were evaluated on total tyrosine kinase (TK) activity and tyrosine phosphorylation status in HeLa and MCF-7 cells. AA and PGA(2) increased TK activity in both HeLa and MCF-7 cells. Western blotting employing an anti-phosphotyrosine antibody showed only one protein of approximately 55 kDa (approximately 55 kDa) to be phosphorylated in the MCF-7 cells, while a variety of proteins were phosphorylated in the HeLa cells, including the approximately 55 kDa protein. Amino acid analyses as well as Matrix Assisted Laser Desorption Ionization were conducted on this protein from different cell lines and it was shown to be similar. Comparison to p53 did not show similarities. The identity of this protein needs to be further characterized to help elucidate the signal transduction pathways of AA and PGA(2)., (Copyright 2001 Harcourt Publishers Ltd.)

In this study the effect of single and concomitantly added n-6 or n-3 polyunsaturated fatty acids (PUFAs) was investigated on human prostate cells. Data obtained from the single fatty acids (FAs) experiments showed that except for oleic acid (OA), arachidonic (AA) and linoleic acid (LA), which had very little (less than 10% cells dead) effect on the cells, an increase in dead cells was observed at physiological concentrations of, eicosapentaenoic acid (EPA), gamma-linolenic acid (GLA) and alpha-linolenic acid (ALA). However, this was not the case when combining these acids at physiological concentrations. A slight increase in cell death was only obtained with three combinations of ALA, namely with AA, OA, or GLA. Other combinations with ALA, such as with LA or EPA, had respectively no effect on cell number or increased the cell number by causing less cells to die. Other PUFAs combinations tested, did not show the three groups mentioned with ALA, but only the last two types, namely, no effect, or a decrease in the amount of cell death. The latter might mean that the FA combination had stimulated the cells, since a decrease in the amount of dead cells was observed. Therefore, it is concluded that the characteristics of combined FAs may differ from single FAs, which may explain some controversies in the literature and in response to treatments.

The presence of caveolae in many cell types including heart myocytes is well established. It is hypothesized that caveolae may play a role in the storing of excess Ca2+ and may be instrumental in Ca2+ transients during contraction and relaxation in pathological conditions. Furthermore, the presence of substances in caveolae and in their membranes may imply a role in the importing and exporting of key molecules under physiological and pathological conditions. Secretory activity is also suggested by an electron micrograph of rat heart muscle.

Renal stone formation is a complex multifactorial disease, and it is believed that the initial step in the pathogenesis of urolithiasis must be the precipitation of an organic matrix of mucoproteins followed by precipitation of minerals onto this matrix. An important factor in this process may be the activity and/or concentration of the urinary enzyme, urokinase, which would affect the level of urinary mucoproteins such as uromucoid. In support of this hypothesis, ELISA studies were conducted to investigate the urokinase concentrations in urine obtained from males (22-60 years) with and without renal stones. These results showed a significant decrease in urinary urokinase concentration of renal stone patients which, once again, underlines the possible involvement of urokinase in renal stone formation. Therefore, it seems logical to conclude that urokinase may play an integral role in this multifactorial disease.

A wide range of intra- and extracellular microbial proteases has been studied and characterized. These enzymes are mostly extracellular and in some cases they may resemble 'classical' serine proteases. As part of a programme in which the lipase and protease activities of the fungus Geotrichum candidum are being studied, an intracellular protease with an apparent chymotrypsin-like specificity was detected. The serine protease was isolated from biomass using ion-exchange and exclusion chromatography. Kinetic characterization was done using a series of synthetic substrates and inhibitors. Aprotinin-sepharose affinity chromatography was used to isolate a fraction for molecular size determination on SDS-PAGE. The purified protease, which could hydrolyse haemoglobin as protein substrate, was obtained with a 30-fold purification and a yield of 44%, but it was very unstable and rapidly lost activity. The enzyme which bound to the affinity column had a single subunit mass of 278 kDa. Kinetic analysis showed a similarity with trypsin and chymotrypsin, but tending more towards chymotrypsin in that a bulky aromatic group, e.g. phenylalanine in the P1 position, was preferred. The optimum pH was in the region of 7-8.25. Inhibition patterns indicated that the enzyme was a serine protease with no metal dependence, although it was stabilized by magnesium ions. The enzyme seems to share some properties with other intra- and extracellular microbial serine proteases. The exact function of the enzymatic activity is still unclear, but it is suggested that it may be involved with intracellular protein turnover.

An unacceptably high incidence of preterm labour is seen in the black and coloured communities of South Africa. This hypothesis proposes that sodium-potassium adenosine triphosphatase activity plays an important role in preterm labour. The impaired activity of the sodium pump leads to increased cytosolic calcium levels, which may trigger contraction of myometrial smooth-muscle cells, resulting in preterm labour.

Urokinase-type plasminogen activator (uPA) is an important protease enzyme in carcinogenesis, and is involved in both invasion and metastasis of cancer. Increased uPA activity and decreased essential fatty acid (EFA) levels have been reported in cancer. This phenomenon may be explained by the fact that certain EFAs, such as gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA), inhibit uPA activity. The effect of EFA on human prostate DU-145 cell growth and uPA production is still unknown and was investigated in this study. Data obtained from the different unsaturated fatty acids showed that oleic acid (OA) and EPA enhanced DU-145 cell proliferation at 0.004 and 0.04 mM for up to 4 days. However, alpha-linolenic acid (ALA), linoleic acid (LA), GLA and arachidonic acid (AA) suppressed cell proliferation under the same conditions, possibly as a result of inhibition of DNA and protein synthesis as measured using labelled thymidine and glycine incorporation. In contrast to the cell proliferation, uPA production was inhibited by all the unsaturated fatty acids under investigation. Therefore, the absence of EFAs, as reported, may affect invasion and metastasis of cancer.

Many hypotheses have been proposed for renal stone formation. It has been argued that with infection-induced renal stones the hydrolysis of urea by bacterial urease increases urinary pH, with consequent stone formation. Unfortunately, this theory is not applicable to the micro-organisms that do not produce urease (e.g. Escherichia coli). It has been recently reported that E. coli reduces the urinary urokinase activity of male rats, but does not influence the urinary sialidase activity. This study has now been expanded to the urease-producing bacteria Proteus mirabilis, Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa and Micrococcus luteus. Subcutaneous injections with these bacteria were found to significantly (P < 0.003) reduce the UK activity of extrarenally obstructed kidneys. The urease-producing mammalian skin bacterium, M. luteus, was, however, the exception (P = 0.1079). In contrast to S. epidermidis, P. aeruginosa and M. luteus (P < 0.0213), P. mirabilis and S. aureus had no effect on renal sialidase activity (P < 0.4047). These results may explain why Proteus species are predominant in infection-induced renal stones. According to the urokinase-sialidase hypothesis, a decrease in urinary urokinase activity should increase the uromucoid levels, whilst no effect on the urinary sialidase activity should favour conversion of urinary uromucoid to mineralizable matrix. These conditions may lead to renal stone formation. An increase in urinary pH resulting from urease-producing micro-organisms will increase salt precipitation on the uromucoid. It is thus concluded that urease-producing bacteria may play a double role in renal stone formation.

Malignant cells show increased urokinase (UK) activity and decreased peroxidation of essential fatty acids (EFA). In order to explore this phenomenon the effect of UK on the lipoxidase activity was spectrophotometrically investigated. Decreased lipoxidase activity was obtained with increased UK concentrations (r = -1.000, p < 0.0001). This proteolytic effect of UK on lipoxidase was eliminated with the addition of the UK inhibitor leupeptin. These results suggest that the increase in UK activity in malignant cells may decrease the lipoxidase activity and thus peroxidation of EFA. The effectiveness of a given EFA in killing cancer cells would therefore depend on the modulation of the lipoxidase activity by the UK-type plasminogen activator.

Urokinase (UK) is an important protease enzyme in carcinogenesis, and is involved in the invasion and metastasis of cancer. Thus, regulation of UK activity is likely to be important in healthy cell metabolism. As it has been reported that a decrease in delta 6-desaturated essential fatty acid (EFA) metabolites occurs in malignant cells and that gamma-linolenic acid (GLA) and eicosapentaenoic acid (EPA) exert antimutagenic effects, the effects of GLA and EPA on UK activity have been investigated in this study. Both GLA (n-6) and EPA (n-3) acted as competitive inhibitors of UK with Ki values of 120 and 96 microM respectively. No modification of plasmin activity occurred with either 1.4 x 10(-4) M GLA or EPA. These results could explain why malignant cells with decreased EFA concentrations show increased UK activity. The addition of EFAs to available therapeutic regimens may be worth considering in the treatment of cancer.

Renal stone formation can be caused by many different and varied disturbances, some of which are poorly understood. The relationship between urinary infection and renal stone formation has not been completely clarified. It is argued that renal stones form primarily as a consequence of the hydrolysis of urea by the bacterial enzyme urease. However, no explanation is given for microorganisms that produce urease only occasionally or not at all. The question arises as to whether the infection-induced microorganisms might not be playing a double role in renal stone formation by not only producing urease, but also by affecting in vivo urokinase (UK) and sialidase (SA) activity. With this in mind, the effect of Escherichia coli on renal UK and SA activity has been studied in male rats with a normal diet. The renal UK (P = 0.208) and SA (P = 0.2135) activities did not differ significantly between the two kidneys of the same rat. In contrast, when drainage from one kidney of a rat was externally obstructed, the UK and SA activities differed significantly between kidneys (P < 0.015). An increase in UK (r = 0.6456, P < 0.0001) and SA (r = 0.7507, P < 0.0001) activity was observed over time in the obstructed kidney. Subcutaneous injections with E coli reduced the UK activity of the obstructed kidney significantly (p = 0.017). However, the SA activity remained the same (P = 0.3929).(ABSTRACT TRUNCATED AT 250 WORDS)

This study was undertaken to assess whether additions of different oils to the diets of male rats would affect the renal urokinase (UK) activity of healthy and pyelonephritic kidneys. Four groups of fatty acid diets were studied: fat-free, coconut oil, fish oil and evening primrose oil (EPO). Pyelonephritis was obtained by unilateral extrarenal urinary obstruction and subcutaneous injection of Escherichia coli. The UK activity of the non-obstructed kidneys did not differ statistically between rats infected and not infected with bacteria (P > 0.056), except within the coconut oil group. A statistically decreased UK activity was obtained with bacteria injected animals on a coconut oil diet (P < 0.0001). This phenomenon, namely a decrease in UK activity, was also seen with pyelonephritic kidneys of rats on fat-free, coconut and fish oil diets (P < 0.0065). However, the UK activity of the obstructed kidneys with and without infection in the EPO group remained similar (P = 0.8477). These results suggest that the UK activity in infection-induced renal stones may be restored by EPO containing diets and may be of high relevance in the prevention and treatment of infection-induced renal stones. This revelation now needs to be more fully investigated.

The effect of a promoter (calcium) and an inhibitor (magnesium) of urolithiasis was spectrophotometrically studied on urokinase (0.45 IU) and sialidase (5 mM). Although these mineral did not affect the sialidase activity, total inhibition of urokinase activity was observed with either 0.05 M calcium chloride or 0.1 M magnesium chloride. This observation might explain why calcium and magnesium respectively function as a promoter and an inhibitor of stone formation.

It has been hypothesized that urinary urokinase and sialidase may play a role in urolithiasis. If these theories have substance it is to be expected that microorganisms may also affect these enzymes, since the association between urinary tract infection and renal stone formation is well known. It is generally assumed that Proteus mirabilis and Staphylococcus albus, which produce the urea-splitting enzyme urease, are responsible for stone formation. However, the importance of non-urease-producing microorganisms (Escherichia coli and Enterococcus) in urolithiasis is unclear. Spectrophotometric studies were therefore devised to clarify this problem. Microorganisms associated with infection-induced stones (Proteus mirabilis and Escherichia coli) respectively inhibited the urokinase and stimulated the sialidase activity. In contrast, microorganisms which were not associated with infection stones (Bacillus subtilis) had significantly less effect on urokinase and sialidase activity. This study may explain infection-induced stone formation and could open a completely new line of research.

Cell-free extracts of a selection of yeasts were analysed for urease activity. Species in the genera Filobasidiella, Rhodotorula and Rhodosporidium had the highest specific activities. Immune inactivation experiments showed widely different degrees of cross-reactivity between antiserum to jack bean urease and yeast ureases, with Rhodosporidium paludigenum (71%) the most and Schizosaccharomyces pombe (3%) the least affected. Only R. paludigenum urease was detected with anti-jack bean urease antiserum on Western blots. The urease of Rhodosporidium paludigenum was partially purified by column chromatography. The native enzyme was found to have a subunit size of 72 +/- 7 kDa probably in an octamer arrangement of 560 +/- 8 kDa, having a specific activity of 62.5 mumol urea hydrolysed min-1 (mg protein)-1. The enzyme was stable in the pH range 5-11 with optimum activity at pH 7.8. Vmax and Km values were determined as 65.2 +/- 3.8 mumol min-1 (mg protein)-1 and 3.81 +/- 0.47 mM, respectively.

Human seminal plasma specimens from 62 patients were collected and divided into three groups according to their fertility state. Five protein peaks, obtained by column chromatography, were used in lymphocyte transformation studies to measure their effect on blast transformation rates. The results expressed as percentage inhibition showed that the immunosuppressive activity of isolated seminal plasma fractions were more marked than whole seminal plasma. There was no statistical correlation between inhibition caused by each fraction and the fertility state of the patient groups. Inhibitory components do not seem to relate to the amount of sperm cells in the ejaculate.

Both the forward and backward reactions of xylose isomerase (Sweetzyme Q) with xylose and glucose as substrates have been studied in terms of kinetics and thermodynamics. The relationship between the two reactions can thus be determined. Much attention has been given to the reaction with xylose as substrate. The optimal conditions of the xylose reaction in terms of pH, buffer, metal ions, substrate concentration, temperature, and ionic strength have been determined. These findings did not differ much from those reported for the glucose reaction. Equilibrium constants for the aldose to ketose conversion were more favorable in the case of glucose. The results obtained with continuous isomerization of xylose in columns packed with either Sweetzyme Q or Taka-Sweet were very similar to those obtained from batch isomerization processes. Particle size had a definite effect on reaction rate, which indicates that diffusion limitations do occur with the immobilized enzyme particles. Heat stability of Sweetzyme Q was good with t(1/2) of 118, 248, and 1200 h at 70, 55, and 40 degrees C, respectively. A novel method for the separation of xylose-xylulose mixtures with water as eluant on a specially prepared Dowex 1 x 8 column was developed. This technique has the capability of producing pure xylulose for industrial or research applications. A writ for a patent regarding this technique is at present prepared.

Individual monosaccharides present in bagasse hemicellulose were determined using HPLC and other chromatographic procedures. The presence of higher oligomers of the monosaccharides could also be determined. No single procedure can separate and identify all the naturally occurring monosaccharides. The pentosan fraction of bagasse wa successfully hydrolyzed and extracted with 5% (m/v)HCl, and the rate of release of individual monosaccharides was determined. Xylose was the main component in the hydrolyzates, while glucose, arabinose, and galactose present in the side chains of the pentosans were initially released at a fast rate. This treatment resulted in obtaining 229 mg/g xylose (85% of theoretical maximum) and 44 mg/g glucose from bagasse. Only arabinose (2.8 mg/g) and galactose (0.75 mg/g) was also present in detectable quantities. A total of 309 mg monosaccharides were obtained from 1 g of bagasse by this treatment. The results indicated that hydrolysis conditions for specific plant materials depend on the composition of the specific material being utilized. A part of the pentosan fraction (77.1%) was hydrolyzed at a high rate, while 22.9% was more stable and hydrolyzed more slowly. Although 39.8% dry bagasse could be obtained in solution by treatment with dilute alkali, only about 72% of the available hemicelluloses could be extracted in this way if the bagasse was not delignified beforehand. Amino acids and peptides or proteins were also extracted to very much the same with the alkali.

A new protease was isolated from an extract of leaves of Agave americana variegata. The protease (EC 3.4.-) was purified 565-fold with a yield of 39.5%. The 43.8 mg enzyme had a specific activity of 0.44 units/mg. According to electrophoretic, ultracentrifugal and other physical characterizations the enzyme was homogeneous. The enzyme had a MR of 57000, a S20,W-value of 4.37 S, a D20, W-value of 6.8-7.0 - 10(-7) cm2sec-1, a Stokes radius of 3.18 nm, a partial specific volume of 0.735 cm3g-1, a frictional ration of 1.25, a molecular absorbancy index at 280 nm of 5.773-10(4), an isoelectric point of 5.25 and contained 8-10% carbohydrate. The enzyme contained no cysteine. Agave protease could hydrolyze a variety of protein substrates although it did have a restricted specificity. It is not a sulphhydryl protease but seems to be an alkaline "serine" protease with an optimum pH of 7.8-8.0 Agave protease had marked esterolytic activity and with Cbz-Tyr-ONp had an apparent Michaelis constant of 0.0345 -10(-3) M and a V of 1.24 mol substrate/mol enzyme per sec. The enzyme did not need metal ions for optimal activity, monovalent cations did not influence its kinetic parameters, but it was inhibited by cobalt, pC1HgBzO- and TosPheCH2C1. With respect to its primary specificity, as well as its pH-dependence there was a resemblance with chymotrypsin, although the rate of hydrolysis of Agave protease is much lower.

The peripheral lymphocytes of eleven healthy homosexual men and six heterosexual males were used in microlymphocyte culture systems to compare their transformation rates in the presence of PHA-M. Two homosexual men were randomly selected from the group to investigate the influence of seminal plasma fractions on their lymphocytes. The seminal plasma fractions were obtained from heterosexual normozoospermic men. Seventy two percent of the homosexual T-cell responsiveness to PHA was inhibited compared with the lymphocytes of the heterosexual men. The lymphocytes of the homosexual male seem to be less sensitive for the inhibition components present in seminal plasma.