Effects of varicocele upon the expression of apoptosis-related proteins.

Varicocele-associated apoptosis has been recognised as a cause of male infertility. Thus, we assessed the expression of somatic apoptosis-related proteins (the typical protein-dependent apoptosis markers) in ejaculated sperm plasma from both patients with varicocele and normal donors. We evaluated the relationships between certain apoptosis-related proteins and normal semen quality. Semen samples were obtained from 25 patients with varicocele and from 10 normal fertile controls. These samples were compared using computer-assisted semen analysis for motion parameters and manual analysis for morphology, and were also assayed for apoptosis-related protein activation including caspase-3, poly-ACP-ribose polymerase (PARP), the Bcl-2 family (Bcl-2, Bak) and p53 by means of immunoblot analysis. PARP, Bak and p53 were expressed substantially more in the sperm cells of the varicocele group when compared with the normal group (P < 0.05). The expression of caspase-3 and Bcl-2 did not appear to differ between these two study groups. An increased expression of PARP, Bak and p53 for varicocele-afflicted individuals indicated an increased participation by these agents in the regulating of apoptosis in the ejaculated semen from patients with varicocele, suggesting that certain protein-development apoptotic mechanisms might originate in the cytoplasmic droplet or within mitochondria of spermatocytes and then might function within the nucleus of the cell.

Differential interactive effects of gliotoxin and MPTP in the substantia nigra and the locus coeruleus in BALB/c mice.

We have previously demonstrated that chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) infusion to the substantia nigra (SN) and the locus coeruleus (LC) both produce a long-lasting neurotoxicity on dopamine (DA) and norepinephrine (NE) neurons in these two areas, respectively. In the present study, we further examined the toxicity of MPTP in these two areas by using the immunohistochemical method. We have also assessed the role of glia cells in the SN and LC in mediating the toxicity of MPTP. Immunohistochemical results have confirmed the direct toxicity of MPTP in the SN, as revealed by significant decreases of tyrosine hydroxylase (TH)-positive cells in the SN and TH-positive fibers in the striatum. The specific gliotoxin alpha-aminoadipic acid (alpha-AA), when administered to the SN at 48 h interval, partially antagonized DA depletions and behavioral deficits produced by chronic MPTP treatment. When alpha-AA was administered to the SN every 24 h, it completely abolished the toxicity of MPTP. On the other hand, chronic MPTP infusions to the LC significantly decreased DA-beta-hydroxylase-positive cells in this area. When alpha-AA was injected into the LC at 48 h intervals, it did not prevent depletions of NE in the LC and the hippocampus caused by chronic MPTP infusions. It did not protect against the behavioral deficits produced by MPTP, either. When alpha-AA was injected into the LC every 24 h, it only partially prevented the toxicity of MPTP on NE in the LC. It also partially prevented the motor-impairing effect of MPTP; however, it barely protected against MPTP's toxicity on NE in the hippocampus and it did not antagonize the stereotypy deficit produced by chronic MPTP, either. Phasic tremor and rigidity were observed following MPTP infusions to the SN and the LC every day, but these symptoms were less frequently observed during the later experimental stage. Serotonin measures were not significantly altered by these treatments throughout these experiments. Immunoblotting results of glial fibrillary acidic protein (GFAP), a marker protein of astrocytes, have confirmed proper lesions of astrocytes by alpha-AA. These results together suggest that chronic MPTP treatment exerts a direct and long-lasting toxicity on DA neurons along the nigrostriatal pathway and NE neurons along the coeruleus-hippocampal pathway. The neurotoxicity of MPTP is probably mediated through astrocytes in the SN, and may be partly mediated through astrocytes in the LC also. These results imply a role for dendritic uptake of DA and NE in these cell body regions. However, these findings also suggest the possibility of differential mechanisms of MPTP's toxicity in these two areas.

Ocular hypotensive action of ergoline derivatives in rabbits: effects of sympathectomy and domperidone pretreatment.

Ergot derivatives, such as bromocriptine, lergotrile and pergolide, are potent dopaminergic agonists in various biological systems. In topical doses ranging from 0.001 to 1% applied unilaterally, each agent produced dose-related ocular hypotension in normal rabbits. Utilizing an intraocular pressure (IOP) recovery rate method (aqueous formation index), each agent was observed to suppress the recovery rate of IOP in normal rabbits. Pretreatment with a prejunctional dopamine receptor antagonist (domperidone) inhibited the ocular hypotensive effect of bromocriptine and pergolide more than that of lergotrile. In rabbits with unilateral superior cervical ganglionectomies, IOP was lowered appreciably less by these compounds in the denervated eyes. These studies indicate that: a) lowering of IOP by these ergot derivatives is dependent, in part, on suppression of sympathetic neuronal activity; b) the most probable sites of action are DA2 receptors on sympathetic nerve endings or in sympathetic ganglia; c) ocular hypotension is produced, in part, by suppressing aqueous humor formation.

Alteration in ocular function induced by phenylethylamine analogs of dopamine.

Dopamine (DA) and three methylated analogs (N-methyldopamine, NMDA; N, N- dimethyldopamine , DMDA ;N,N-di-n- propyldopamine , DPDA) were examined for effects on intraocular pressure (IOP) and pupil diameter (PD) in normal rabbits, sympathectomized (SX) rabbits and rabbits with transected extraocular muscles ( EOMX ) following topical administration. In normal rabbits, the predominant effect of DA, NMDA and DMDA was transient, unilateral ocular hypertension with minimal effects on PD. In contrast, DPDA produced bilateral ocular hypotension in normal rabbits. DA and NMDA did not produced ocular hypertension in EOMX rabbits indicative of an involvement of extraocular muscles in normal rabbits. In SX rabbits, NMDA produced mydriasis and exaggerated ocular hypertension followed by significant ocular hypotension; the ocular hypotensive phase was antagonized by timolol pretreatment. The ocular hypotensive activity of DPDA seen in normal rabbits was absent in SX rabbits suggestive of a neuronal site of action for DPDA. DPDA inhibited contraction of the cat nictitating membrane elicited by stimulation of pre- and postganglionic sympathetic nerves. This effect was antagonized by a dopamine (DA2) antagonist metoclopramide, indicative of a prejunctional site of action. NMDA and DA suppressed ocular hypertension induced by water loading. Only NMDA depressed the IOP recovery rate in response to infusion of hypertonic saline indicating suppression of aqueous humor formation. These results suggest that DA, NMDA and DMDA produce an initial ocular hypertension by contracting extraocular muscles. Timolol antagonized the ocular hypotensive effect of NMDA in SX rabbits indicating that this response is, in part, a function of beta-adrenoceptor stimulation.(ABSTRACT TRUNCATED AT 250 WORDS)

The pharmacology of cycloplegics.

A brief review of the pharmacological action of cycloplegic drugs is followed by a specification of the doses and actions of five commonly used cycloplegics. Some criterion for selecting a cycloplegic are presented.

An evaluation of the use of topical anesthetics and low concentrations of phenylephrine HCl for mydriasis.

When used in conjunction with a topical anesthetic, low concentrations of phenylephrine HCl produce the same degree of mydriasis as is produced by higher concentrations of the drug used alone. Contrary to previously published reports, however, there is no evidence to suggest that the use of lower concentrations lessens the risk of adverse reactions. The analysis of available information given here suggests that the risks may in fact be increased when an anesthetic is used.

Mechanism of the ocular hypotensive action of ketanserin.

Ketanserin has been characterized as a relatively selective antagonist for serotonin (5-HT2) receptors. However, recent evidence suggests that ketanserin can also antagonize activity at alpha 1-adrenoceptors. Topically applied ketanserin lowered intraocular pressure (IOP) in rabbits, cats, and monkeys. Ketanserin also suppressed ocular hypertension induced by waterloading and the IOP recovery rate in response to hypertonic saline. In contrast, the ocular hypotensive activity of ketanserin was markedly attenuated in sympathectomized (SX) rabbits. In the cat nictitating membrane, ketanserin produced dose-related inhibition of contractions elicited by neuronal stimulation and by intra-arterial injection of norepinephrine. These data demonstrate that ketanserin: 1) lowers IOP more effectively in eyes with intact sympathetic innervation than in SX eyes, 2) appears to lower IOP by suppressing aqueous inflow, and 3) acts primarily by antagonizing the action of norepinephrine on alpha 1-adrenoceptors.

Effect of 30% sodium sulfacetamide on corneal sensitivity.

This study compares the effect of 10 and 30% sodium sulfacetamide on corneal sensitivity. The corneal sensitivity was measured on 11 subjects with a Cochet -Bonnet aesthesiometer without any drug, 10 and 30% sodium sulfacetamide . The results obtained for the mean corneal sensitivities (mean +/- standard error) for the control, 10 and 30% sodium sulfacetamide were 1.07 +/- 0.025, 1.09 +/- 0.023, and 1.36 +/- 0.10 gm/mm2, respectively. We found that there was no statistical difference between the control value and 10% sodium sulfacetamide , but the 30% produced a significant decrease in corneal sensitivity when compared to the control and 10% concentration.

Effects of aminotetralins on intraocular pressure and pupillary function in rabbits.

Aminotetralin compounds, A-6, 7-DTN and TL-99, produced bisphasic changes in intraocular pressure (IOP) and pupillary dilatation in rabbits. The rise in IOP appeared to result from an action on extraocular muscles because this effect was not produced by either compound in rabbits with transected extraocular muscles. The ocular hypotensive action of A-6, 7-DTN and TL-99 was markedly attenuated in sympathectomized rabbits indicating that this action resulted from suppression of sympathetic neuronal activity. Inhibition of ocular hypertension induced by waterloading by both compounds and suppression of the IOP recovery rate by A-6, 7-DTN suggested that the latter compound lowered IOP, in part, by inhibiting aqueous humor formation. The ocular hypotensive action of A-6, 7-DTN was antagonized by pretreatment with sulpiride, but not by yohimbine, indicating that dopamine receptors are involved in the response. These studies demonstrated that dopamine agonists can lower IOP and suggest that these types of drugs might prove useful in the therapy of open-angle glaucoma.

Sector pupil dilation with phenylephrine and tropicamide.

A comparison of sector pupil dilation produced with 2.5% phenylephrine and 1.0% tropicamide was carried out on nine subjects. We found that 2.5% phenylephrine produced a significant increase in the vertical as compared to the horizontal diameter at 10, 20, 30, 40, and 50 min after instillation of the drug with the maximum vertical diameter occurring at 40 min. The pupil diameter in the vertical and horizontal meridians before drug instillation was 3.7 mm +/- 0.2 (mean +/- SE) whereas at 40 min the vertical and horizontal diameters were 6.7 mm +/- 0.4 and 5.2 mm +/- 0.3, respectively. Instillation of 1% tropicamide produced equal dilation of the vertical and horizontal diameters, which was maximum at 40 min. Before drug instillation, the pupils were 3.7 mm +/- 0.2 (mean +/- SE) in both the horizontal and vertical meridians. At 50 min the pupil diameter was 7.0 mm +/- 0.2 in both meridians in the eye that received tropicamide.

Effects of decreasing concentrations of tropicamide on sector pupil dilation.

We compared the effects of decreasing concentrations of tropicamide on sector pupil dilation. The concentrations of 0.25, 0.125, 0.03125, and 0.0156% tropicamide were instilled on 10 subjects and the horizontal and vertical pupil diameters measured at 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, and 90 min after drug instillation. We obtained significant pupil dilation with the 0.25% concentration but with progressively decreasing concentrations we obtained a concomitant decrease in pupil dilation, suggesting that it is the inherent action of the constrictor muscle to respond differently than the dilator muscle (no sector dilation), and this effect is not concentration dependent.

Reversal of intraocular pressure increases with 0.5% apraclonidine after dilated fundus examination in patients with chronic open-angle glaucoma.

BACKGROUND: Apraclonidine 1.0% has been shown to reverse the potential intraocular pressure (IOP) increase after pupil dilation IOP increases in patients with chronic open-angle glaucoma. However, it is only approved for preventing IOP spikes after laser surgery. The purpose of this study is to determine the effectiveness of 0.5% apraclonidine in reversing IOP increases after pupillary dilation in patients with chronic open-angle glaucoma. METHODS: Twenty-two patients with chronic open-angle glaucoma were found to have an increase in post-dilation IOP of at least 4 mmHg from pre-dilated levels (baseline) in both eyes. IOP was measured 1 hour after dilation, after which two drops of 0.5% apraclonidine were instilled in one eye and the IOP was remeasured 15 minutes later in both eyes. Instillation of 0.5% apraclonidine in one eye was continued every 15 minutes and IOP was measured 15 minutes after each instillation, until the pressure returned to baseline levels. RESULTS: The IOP of the initially treated eye of all 22 patients returned to within levels clinically insignificant from baseline IOP within 90 minutes. By comparison, the IOP of the control group (untreated eye) remained elevated. Once the initial treatment eye returned to baseline levels, the control group was then treated with 0.5% apraclonidine, resulting in a lowering effect of the IOP in similar fashion to the initial treated group. CONCLUSIONS: Apraclonidine 0.5% appears to be effective in reduction of post-dilated IOP increases in patients with chronic open-angle glaucoma.

Neurotoxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in the substantia nigra and the locus coeruleus in BALB/c mice.

The purpose of the present study was to determine whether 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), administered systemically or as a local infusion, has a direct neurotoxic action upon dopamine (DA) neurons in the substantia nigra (SN) and norepinephrine (NE) neurons in the locus coeruleus (LC) in BALB/c mice. Results indicated that both acute and repeated MPTP infusions (2 micrograms/0.3 microliter per side) significantly impaired locomotor activity, decreased stereotyped behavior and caused a disturbed pattern of locomotion in mice. The biochemical changes parallel the behavioral changes. Repeated MPTP infusions to the SN decreased DA levels markedly in the SN and the striatum; chronic MPTP infusions to the LC reduced NE levels markedly in the LC and the hippocampus. Furthermore, repeated MPTP injections for 7 days (30 mg/kg, one injection per day) have resulted in a long-lasting effect on both the nigral-striatal and the coeruleus-hippocampal systems. DA levels in the SN and the striatum were decreased at 1, 3, 7 and 28 days after the last MPTP injection. Similarly, NE levels in the LC and the hippocampus were also reduced markedly at the same time intervals examined. Behaviorally, repeated MPTP treatment also produced long-lasting motor deficits in mice at all time intervals studied. Moreover, the LC appeared to be more sensitive than the SN to the neurotoxic effects of MPTP. Immunohistochemical results have similarly revealed that repeated MPTP treatment markedly decreased tyrosine hydroxylase-positive cells and fibers in the SN and the LC. It also markedly decreased DA-beta-hydroxylase-positive cells and fibers in the LC.(ABSTRACT TRUNCATED AT 250 WORDS)