Minimizing photodecomposition of flavin adenine dinucleotide fluorescence by the use of pulsed LEDs.

Dynamic alterations in flavin adenine dinucleotide (FAD) fluorescence permit insight into energy metabolism-dependent changes of intramitochondrial redox potential. Monitoring FAD fluorescence in living tissue is impeded by photobleaching, restricting the length of microfluorimetric recordings. In addition, photodecomposition of these essential electron carriers negatively interferes with energy metabolism and viability of the biological specimen. Taking advantage of pulsed LED illumination, here we determined the optimal excitation settings giving the largest fluorescence yield with the lowest photobleaching and interference with metabolism in hippocampal brain slices. The effects of FAD bleaching on energy metabolism and viability were studied by monitoring tissue pO2 , field potentials and changes in extracellular potassium concentration ([K+ ]o ). Photobleaching with continuous illumination consisted of an initial exponential decrease followed by a nearly linear decay. The exponential decay was significantly decelerated with pulsed illumination. Pulse length of 5 ms was sufficient to reach a fluorescence output comparable to continuous illumination, whereas further increasing duration increased photobleaching. Similarly, photobleaching increased with shortening of the interpulse interval. Photobleaching was partially reversible indicating the existence of a transient nonfluorescent flavin derivative. Pulsed illumination decreased FAD photodecomposition, improved slice viability and reproducibility of stimulus-induced FAD, field potential, [K+ ]o and pO2 changes as compared to continuous illumination.

First measurement of the form factors in the decays D0 → ρ- e+ ν(e) and D+ → ρ0 e+ ν(e).

The beauty to up quark coupling constant |V(ub)| can be extracted from B → ρ e+ ν(e) combined with the form factors for D → K* e+ ν(e) and B → V ℓ+ ℓ- and D → ρ e+ ν(e). Using the entire CLEO-c ψ(3770) → DD event sample, corresponding to an integrated luminosity of 818 pb(-1) and approximately 5.4×10(6) DD events, we measure the form factors for the decays D0 → ρ- e+ ν(e) and D+ → ρ0 e+ ν(e) for the first time and the branching fractions with improved precision. A four-dimensional unbinned maximum likelihood fit determines the form factor ratios to be V(0)/A1(0)=1.48±0.15±0.05 and A2(0)/A1(0)=0.83±0.11±0.04. Assuming Cabibbo-Kobayashi-Maskawa unitarity, the known D meson lifetimes, and our measured branching fractions we obtain the form factor normalizations A1(0), A2(0), and V(0). We also present a measurement of the branching fraction for D+ → ω e+ ν(e) with improved precision.

Observation of the h(c)(1P) Using e+ e- collisions above the DD threshold.

Using 586 pb(-1) of e+ e- collision data at E(c.m.) = 4170 MeV, produced at the Cornell Electron Storage Ring collider and collected with the CLEO-c detector, we observe the process e+ e- → π+ π- h(c)(1P). We measure its cross section to be 15.6±2.3±1.9±3.0 pb, where the third error is due to the external uncertainty on the branching fraction of ψ(2S) → π0 h(c)(1P), which we use for normalization. We also find evidence for e+ e- → ηh(c)(1P) at 4170 MeV at the 3σ level and see hints of a rise in the e+ e- → π+ π- h(c)(1P) cross section at 4260 MeV.

The Restless Spinal Cord in Degenerative Cervical Myelopathy.

BACKGROUND AND PURPOSE: The spinal cord is subject to a periodic, cardiac-related movement, which is increased at the level of a cervical stenosis. Increased oscillations may exert mechanical stress on spinal cord tissue causing intramedullary damage. Motion analysis thus holds promise as a biomarker related to disease progression in degenerative cervical myelopathy. Our aim was characterization of the cervical spinal cord motion in patients with degenerative cervical myelopathy. MATERIALS AND METHODS: Phase-contrast MR imaging data were analyzed in 55 patients (37 men; mean age, 56.2 [SD,12.0] years; 36 multisegmental stenoses) and 18 controls (9 men, P = .368; mean age, 62.2 [SD, 6.5] years; P = .024). Parameters of interest included the displacement and motion pattern. Motion data were pooled on the segmental level for comparison between groups. RESULTS: In patients, mean craniocaudal oscillations were increased manifold at any level of a cervical stenosis (eg, C5 displacement: controls [n = 18], 0.54 [SD, 0.16] mm; patients [n = 29], monosegmental stenosis [n = 10], 1.86 [SD, 0.92] mm; P < .001) and even in segments remote from the level of the stenosis (eg, C2 displacement: controls [n = 18], 0.36 [SD, 0.09] mm; patients [n = 52]; stenosis: C3, n = 21; C4, n = 11; C5, n = 18; C6, n = 2; 0.85 [SD, 0.46] mm; P < .001). Motion at C2 differed with the distance to the next stenotic segment and the number of stenotic segments. The motion pattern in most patients showed continuous spinal cord motion throughout the cardiac cycle. CONCLUSIONS: Patients with degenerative cervical myelopathy show altered spinal cord motion with increased and ongoing oscillations at and also beyond the focal level of stenosis. Phase-contrast MR imaging has promise as a biomarker to reveal mechanical stress to the cord and may be applicable to predict disease progression and the impact of surgical interventions.

Segmental differences of cervical spinal cord motion: advancing from confounders to a diagnostic tool.

Increased cranio-caudal spinal cord motion is associated with clinical impairment in degenerative cervical myelopathy. However, whether spinal cord motion holds potential as a neuroimaging biomarker requires further validation. Different confounders (i.e. subject characteristics, methodological problems such as phase drift, etc.) on spinal cord motion readouts have to be considered. Twenty-two healthy subjects underwent phase contrast MRI, a subset of subjects (N = 9) had repeated scans. Parameters of interest included amplitude of velocity signal, maximum cranial respectively maximum caudal velocity, displacement (=area under curve of the velocity signal). The cervical spinal cord showed pulse synchronic oscillatory motions with significant differences in all readouts across cervical segments, with a maximum at C5. The Inter-rater reliability was excellent for all readouts. The test-retest reliability was excellent for all parameters at C2 to C6, but not for maximum cranial velocity at C6 and all readouts at C7. Spinal cord motion was correlated with spinal canal size, heart rate and body size. This is the first study to propose a standardized MRI measurement of spinal cord motion for further clinical implementation based on satisfactory phase drift correction and excellent reliability. Understanding the influence of confounders (e.g. structural conditions of the spine) is essential for introducing cord motion into the diagnostic work up.

[Modified Salter innominate osteotomy in adults]. / Modifizierte Salter-Innominatum-Osteotomie für Erwachsene.

OBJECTIVE: The dysplastic acetabulum is shifted three-dimensionally outwards and forwards. INDICATIONS: Symptomatic residual hip dysplasias and hip subluxations in skeletally mature patients up to the age of 50 years. Sharp's acetabular up to 60°, as an exception above 60°. CONTRAINDICATIONS: Acetabular retroversion. Radiographic joint space at the lateral acetabular edge that is less than half the normal thickness for the patient's age. Relative contraindication: Elongated leg on the affected side. SURGICAL TECHNIQUE: Ilioinguinal approach in a supine position. Division of the innominate bone. Pivoting the distal osteotomy fragment outwards and forwards with the aid of the Salter maneuver. Fixing the fragments with a guide wire. Final correction of the osteotomy fragments. Force fitting of a dovetail grooved, wedge-shaped bone graft. Insertion of a cannulated compression screw and two further threaded rods. Wound closure. POSTOPERATIVE MANAGEMENT: Unloaded 3­point walking for 4 weeks. Increasing weight bearing from week 4. Full weight bearing from week 10-12. RESULTS: A total of 45 consecutive patients (7 men, 38 women, 49 hips) underwent surgery. Average age at surgery was 27.6 years. The Sharp acetabular angle improved from preoperatively 45.7°â€¯± 4.2° by 13.8° to 32.0°â€¯± 6.4°; the Wiberg (LCE) angle increased from 15.4°â€¯± 9.3° by 19.5° to 34.9°â€¯± 10° postoperatively. The anterior center edge (ACE) angle increased from 28.9°â€¯± 10.4° by 8.6°â€¯± 2.3° to 37.5°â€¯± 8.1°. Complications requiring surgical intervention occurred in 7 patients.

Normative data of contact heat evoked potentials from the lower extremities.

Contact heat evoked potentials (CHEPs) have become an acknowledged research tool in the assessment of the integrity of the nociceptive system and gained importance in the diagnostic work-up of patients with suspected small fiber neuropathy. For the latter, normative values for CHEP amplitude and latency are indispensable for a clinically meaningful interpretation of the results gathered in patients. To this end, CHEPs were recorded in 100 healthy subjects over a wide age range (20-80 years) and from three different dermatomes of the lower extremities (L2, L5, and S2). A normal baseline (35-52 °C) and increased baseline stimulation (42-52 °C) were applied. Statistical analysis revealed significant effects of stimulation site, stimulation intensity, and sex on CHEP parameters (N2 latency, N2P2 amplitude, and NRS). Significant positive correlations of body height with N2 latency, and pain ratings with N2P2 amplitudes were observed. This is the first time that normative values have been obtained from multiple dermatomes of the lower extremities. The present dataset will facilitate the clinical application of CHEPs in the neurophysiological diagnosis of small fiber neuropathy and by discerning pathological findings help establish a proximal-distal gradient of nerve degeneration in polyneuropathies.

Contact heat evoked potentials: Reliable acquisition from lower extremities.

OBJECTIVE: To investigate test-retest reliability of contact heat evoked potentials (CHEPs) from lower extremities using two different stimulation protocols, i.e., normal and increased baseline temperature. METHODS: A total of 32 able-bodied subjects were included and a subset (N = 22) was retested. CHEPs were recorded from three different dermatomes of the lower extremity (i.e., L2, L5, and S2). Test-retest reliability of CHEPs acquisition after simulation in various lower limb dermatomes using different stimulation protocols was analyzed. RESULTS: The study revealed an improved acquisition of CHEPS employing the increased baseline protocol, particularly when stimulating more distal sites, i.e., dermatome L5 and S2. Based on repeatability coefficients, CHEP latency (N2 potential) emerged as the most robust CHEP parameter. Although CHEP amplitudes (N2P2 complex) and pain ratings were decreased in the retest, amplitudes still showed fair to excellent intraclass correlation coefficients using normal baseline or increased baseline temperature, respectively. CONCLUSIONS: This is the first study to demonstrate that CHEPs acquisition from the lower extremities is improved by increasing the baseline temperature of the thermode. SIGNIFICANCE: This study highlights the usability of CHEPs as a viable diagnostic method to study small fiber integrity.

The AraC transcriptional activators.

The AraC family of bacterial transcriptional activators regulate diverse genetic systems. Recent X-ray diffraction studies show that the monomeric MarA and Rob activators bind to their asymmetric degenerate DNA sites via two different helix-turn-helix elements. Activation by MarA, SoxS or Rob requires a particular orientation of the asymmetric binding sequence (and hence the activator), depending on its distance from the -10 RNAP signal. Genetic studies are beginning to clarify how the activators interact with RNAP. Growing evidence suggests that for the sugar metabolism activators, multiple binding sites upstream of the promoter anchor the activator in a repressing or nonactivating configuration. By interaction with the sugar and/or CRP, the activator is allosterically altered so it can bind a new set of sites that enable it to activate the promoter. Surprisingly, the virulence activator, Rns, must bind to both upstream and downstream sites in order to activate the rns promoter.

Magnesium deficiency during pregnancy in mice impairs placental size and function.

OBJECTIVE: Maternal magnesium (Mg) deficiency has been associated with fetal growth restriction. Using a mouse model of maternal Mg deficiency-induced fetal growth restriction, we sought to investigate the effect of Mg deficiency on placental physiology and function. METHODS: In vivo: Pregnant Swiss Webster mice were fed either 100% of the recommended amount of Mg (control) or 10%Mg (Mg-deficient) (8 per group). Dams were euthanized on gestational day 17 and placentas were collected, weighed and assessed for Mg concentrations, as well as nutrient transporter mRNA expression. For nutrient transfer studies, control and Mg-deficient dams (6 per group) were injected with (14)C-amino acids and (3)H-glucose and trans-placental passage was determined. In vitro: BeWo placental cells were grown in media containing 10%Mg to 100%Mg and the effects of Mg status on cell proliferation, oxidative stress and nutrient uptake were measured. Data were analyzed by Student's t-tests comparing controls vs. Mg-deficient animals or cells. For multiple comparisons, data were analyzed by ANOVA followed by Dunnett's post hoc testing. RESULTS: In vivo: Maternal Mg deficiency decreased placental Mg content, placental and fetal weights, ratio of fetal:placental weight (P < 0.05), placental Slc7a5 transporter mRNA expression and transplacental nutrient transport (P < 0.05). In vitro: Mg deficiency reduced BeWo nutrient uptake (P < 0.01) and cell proliferation (P < 0.01), and increased oxidative stress (P < 0.01). CONCLUSION: These findings highlight the adverse effects of maternal Mg deficiency on fetal weight and placental function, including transport and proliferation and may explain the fetal growth restriction observed with moderate Mg deficiency in mice.

Effects of a 48-h fat infusion on insulin secretion and glucose utilization.

To determine the effects of prolonged elevation of plasma free fatty acids (FFAs) on insulin secretion, we infused Liposyn II (4.3 mumol.kg-1.min-1) plus heparin (0.4 U.kg-1.min-1) intravenously into six healthy volunteers for 48 h. Another six volunteers received saline infusions and served as control subjects. In all 12 subjects (11 men and 1 woman), plasma glucose was clamped at approximately 8.6 mmol/l. Liposyn/heparin infusion resulted in a 9.4-fold increase in plasma FFA concentration (from 132 to 1,237 mumol/l), a 46% increase in insulin secretion rates (from 241 to 352 pmol/min, P < 0.05) (determined by deconvolution of plasma C-peptide concentration), and a 30% decrease, during the initial 24 h, in the rate of glucose infusion needed to maintain hyperglycemia (from 55.5 to 39.1 mumol.kg-1.min-1, P < 0.02). This decrease disappeared during the second 24 h. In summary, we found that physiologically elevated plasma FFAs 1) potentiated glucose-stimulated insulin secretion for 48 h and 2) initially caused peripheral insulin resistance that disappeared during the 2nd day, probably as a result of elevated circulating insulin levels. We conclude that in healthy volunteers under hyperglycemic conditions, fat infusion produced insulin resistance that was compensated for after approximately 24 h by persistent hypersecretion of insulin.

Probing the Escherichia coli transcriptional activator MarA using alanine-scanning mutagenesis: residues important for DNA binding and activation.

The MarA transcriptional activator binds to a 20 bp asymmetric degenerate sequence (marbox) located at different positions and orientations within the promoters of the genes of the Escherichia coli mar regulon. Solution of the MarA-marbox X-ray crystallographic structure suggested the presence of base-specific and non-specific interactions between the marbox and two helix-turn-helix (HTH) motifs on the monomeric MarA. Here, we use alanine-scanning mutagenesis and DNA retardation analysis to: (i) evaluate the contacts between MarA and the marboxes of five differently configured mar regulon promoters; (ii) assess the role of conserved hydrophobic amino acid residues for MarA activity; and (iii) identify residues required for RNA polymerase activation. These analyses revealed that the phosphate-backbone contacts and hydrogen bonds with the bases of the marbox are more significant for DNA binding than are the van der Waals interactions. While both N and C-terminal HTH motifs make essential contributions to binding site affinity, MarA is more sensitive to alterations in the N-terminal HTH. In a similar way, the activity of MarA is more sensitive to alterations in the hydrophobic core of this HTH. Solvent-exposed amino acid residues located at many positions on the MarA surface are important for activity. Some of these residues affect activity on all promoters and thus, are implicated in maintaining MarA structure whereas several solvent-exposed amino acids not involved in DNA binding were important for MarA activity on specific promoters. The pattern of activation defects defined a class II promoter-specific activating region. However, a localized class I activating region was not apparent. These results suggest that MarA activates transcription by at least two distinct mechanisms. Furthermore, the important role of phosphate contacts in marbox affinity suggests that indirect readout contributes to binding site recognition by MarA.

Structure and dynamics of MarA-DNA complexes: an NMR investigation.

An unanswered question regarding gene regulation is how certain proteins are capable of binding to DNA with high affinity at specific but highly degenerate consensus sequences. We have investigated the interactions between the Escherichia coli transcription factor, MarA, and its diverse binding sites using NMR techniques. Complete resonance assignments for the backbone of the MarA protein complexed with DNA oligomers corresponding to its binding sites at the mar, fumC, micF and the fpr promoters were obtained. Secondary structure analysis based on chemical shifts reveals that regions identified as helical in the X-ray structure of the MarA-mar complex are present in the solution structure, although some of the helices are less well defined. The chemical shift differences between the four complexes confirm that helix 3 and helix 6 constitute the major DNA-binding elements. However, in striking contrast with the X-ray data: (i) the protein appears to be present in two or more conformations in each of the complexes; (ii) no slowly exchanging N(zeta)H(2) protons (indicative of hydrogen bonded groups) were observed by NMR for the two arginine residues proposed to form crucial hydrogen bonds in the X-ray structure; and (iii) regions at the N terminus, not observed in the X-ray structure, may be involved in DNA-binding. Taken together, the NMR results indicate that MarA in its complexes with DNA target sites is in a highly dynamic state, allowing for small but significant rearrangements of the side-chains and/or backbone to bind to the different DNA sequences.

Innervation changes induced by inflammation of the rat thoracolumbar fascia.

Recently, the fascia innervation has become an important issue, particularly the existence of nociceptive fibers. Fascia can be a source of pain in several disorders such as fasciitis and non-specific low back pain. However, nothing is known about possible changes of the fascia innervation under pathological circumstances. This question is important, because theoretically pain from the fascia cannot only be due to increased nociceptor discharges, but also to a denser innervation of the fascia by nociceptive endings. In this histological study, an inflammation was induced in the thoracolumbar fascia (TLF) of rats and the innervation by various fiber types compared between the inflamed and intact TLF. Although the TLF is generally considered to have proprioceptive functions, no corpuscular proprioceptors (Pacini and Ruffini corpuscles) were found. To obtain quantitative data, the length of fibers and free nerve endings were determined in the three layers of the rat TLF: inner layer (IL, adjacent to the multifidus muscle), middle layer (ML) and outer layer (OL). The main results were that the overall innervation density showed little change; however, there were significant changes in some of the layers. The innervation density was significantly decreased in the OL, but this change was partly compensated for by an increase in the IL. The density of substance P (SP)-positive - presumably nociceptive - fibers was significantly increased. In contrast, the postganglionic sympathetic fibers were significantly decreased. In conclusion, the inflamed TLF showed an increase of presumably nociceptive fibers, which may explain the pain from a pathologically altered fascia. The meaning of the decreased innervation by sympathetic fibers is obscure at present. The lack of proprioceptive corpuscular receptors within the TLF does not preclude its role as a proprioceptive structure, because some of the free nerve endings may function as proprioceptors.

Changes in (3H)leucine incorporation into pineal proteins following estradiol or testosterone administration: involvement of the sympathetic superior cervical ganglion.

Pineal denervation by superior cervical ganglionectomy (Gx) decreased high affinity binding of estradiol (E2) to the pineal cytosol of female rats and of testosterone to the cytosol of male rats by 40 and 26% and by 75 and 80%, 5 and 14 days after sugery; hormone binding remained unchanged up to 24 h after surgery. Binding to the nuclear fraction decreased sigificantly by 2 weeks after incorporation of (3H) leucine into pineal proteins in Gx. A single injection of E2 (mug) to testosterone propionate (TP) (500 mug) failed to increase the Gx rats when injected 1 or 5 days after surgery. Significant increases were observed in sham-operated controls or in rats subjected to bilateral decentralization of ganglia; however on the 5th day an impairment was observed in hormone ability to enhance [3H]leucine incorporation in decentralized rats. The administration of isoproterenol 19 and 3 h before sacrifice replenished pineal-binding sites for E2 and testosterone in Gx rats, but failed to restore the responsiveness of denervated pineals to hormone administration. Moreover, E2 or TP treatment blocked the increase in labeled amino acid incorporation into proteins brought about by isoproterenol per se. The administration of propranolol 2 and 7 h after hormone injection decreased the ability of E2 and TP to enhance [3H]leucine incorporation by 55 and 41%, respectively. Tyrosine hydroxylase activity of the superior cervical ganglia decreased by 36 and 41% 6 h after E2 or TP administration, and by 43 and 47% after 3 daily injections of the hormones, whereas pineal tyrosine hydroxylase remained unchanged. Hormone treatment for 3 days increased the in vitro uptake of norepinephrine by the ganglia but did not affect uptake in the pineal gland. These data indicate that the integrity of neurons of the superior cervical ganglia is an absolute requirement for E2 and testosterone to enhance [3H]leucine incorporation into pineal proteins in rats.

The secretion of progesterone during the periovulatory period in women with certified ovulation.

A pre-LH peak rise of progesterone in peripheral blood has been found in 13 normal cycling women whose ovulation was confirmed by biopsy of the corpus luteum through serial determination of progesterone and LH performed every 8 h during the periovulatory period. The progesterone rise began as an average 22 h (16-40 h) prior to the LH peak. The maximal preovulatory rise took place 9.6 h (0-24 h) before the LH zenith, remaining low for approximately 17 h when an abrupt rise of progesterone took place. The progesterone peak was detected in the morning samples in 11 of 13 patients studied. The progesterone rise was always followed by an LH peak and the highest peak of progesterone was trailed by the highest LH peak in all the patients except one.

Daily variations of FSH, LH and testosterone response to intravenous luteinizing hormone-releasing factor (LRF) in normal men.

The responses of FSH, LH and testosterone to acute stimulation with synthetic LRF were studied in 6 healthy, fertile men aged 33.4 plus or minus 1.6 yr (X plus or minus SE). Fifty mug of LRF were given, iv at 0600 h, 1200 h, 1800 h and 0000 h, at 1-week intervals, to all 6 volunteers simultaneously. Blood samples were collected by venipuncture before (-5 and 0 min) and 8, 16, 32, 64 and 128 min after LRF injection. Plasma levels of FSH, LH and testosterone were determined by double antibody radioimmunoassay techniques. The responses of FSH and LH to LRF injection showed a clear difference at the times studied. Maximal values were obtained at 0600 h and 1800 h while the response at noon was not significant for LH and absent for FSH. Testosterone secretion showed a clear-cut response to LRF in all the subjects. At three of the four studied times (0600 h, 1800 h, 000 h) plasma testosterone was already increased at 8 min reaching its maximum at 16 min and persisted high until the end of the study. The noon response reached its maximum at the end of the test period. The daily variations of FSH and LH responses to acute LRF stimulation should be taken into consideration in clinical practive and the increment in testosterone secretion makes this test a useful indicator for androgenic testicular reserve.

Functional expression of human glucose-6-phosphate dehydrogenase in Escherichia coli.

The complete coding sequence for human glucose-6-phosphate-dehydrogenase (G6PD) was inserted downstream from the tac promoter of a plasmid, pJF118EH, which also carries the lacIq repressor gene. When Escherichia coli strains (that are unable to grow on glucose due to the absence of functional zwf (G6PD-) and pgi genes) were transformed with this plasmid (pAC1), they were able to grow on glucose as sole carbon source. The rate of growth on glucose was faster in the presence of the inducer of the tac promoter, isopropyl-beta-D-thiogalactopyranoside (IPTG). Extracts of the transformed cells contained a G6PD activity that was not detectable in the parental strains and that was inducible by IPTG. The G6PD activities from normal E. coli and from pAC1-transformed cells comigrated with human G6PD when subjected to electrophoresis on agarose gels. However, when denatured, the G6PD produced by pAC1 was, like the human enzyme, distinguishable from the E. coli-encoded enzyme on the basis of its immunoreactivity with antibody specific for human G6PD. Therefore, human G6PD can be expressed in E. coli and can function to complement the bacterial enzyme deficiency.

Further evidence for histamine facilitating oestrogen action in the uterus.

The effect of doses of estradiol ranging from 0-0125 to 1-6 mug on the uterine weight of the spayed rat was studied 24 h after a single s.c. injection of the hormone. The lowest dose inducing a significant increase in uterine weight was 0-32 mug. When histamine dihydrochloride (50 mg) was simultaneously injected with the hormone, the effect of small doses of oestradiol (0-0125--0-2 mug) was significantly increased. When oestradiol and histamine were administered for 3 successive days, the uterine weight of animals receiving 0-0125 mug oestradiol, if compared with untreated controls, was increased only in the histamine-treated group. When 0-05 mug oestradiol was administered histamine did not modify the increase already produced by the hormone. Spermidine and burimamide, two substances structurally related to histamine, increased [3H]oestradiol uptake by the spayed rat uterus. The latter (an antihistamine drug acting on H2-receptors) as well as pyrathiazine (a histamine releaser having antihistamine properties) decreased the effect of histamine on oestradiol uptake whereas diphenhydramine (an antihistamine drug blocking H1-receptors) did not modify it. Pyrathiazine was itself able to diminish oestradiol uptake.

A direct effect of antiovulatory compounds on human testicular biosynthesis in vitro.

PIP: Human testes, removed in treating patients for prostatic carcinoma, were used. Tissues were homogenized and incubated in vitro with labeled progesterone and 2 different antiovulatories, lynestrenol (17alpha-ethin yl-17beta-hydroxy-estr-4-one) and MK 665 (17alpha-chloroethinyl-19-nor-4 ,9(10)-androstadiene-17beta-ol-3-one). Further biochemical procedures are described. Results show that the compounds added in vitro to the homogenates inhibited the conversion of progesterone to 17alpha-hydroxyprogesterone, 20alpha-hydroxy-4-pregnene-3-one, and androgens. It is thought that these 2 compounds exert a direct effect on the activity of 2 human testicular enzymes related to the biosynthesis of androgens and on the 20alpha-hydroxy steroid dehydrogenase. With the concentrations employed, no androgen biosynthesis was observed with the larger doses and only partial inhibition with the smaller doses. The action could be on the enzyme systems themselves or on the synthesis of the enzymes. Results are valid for in vitro conditions only.^ieng