Concern for toxicity following exposure to organophosphorus insecticides led us to investigate whether topical application of either malathion or malathion mixed in a protein bait as used for aerial spray applications could be toxic to the ocular/visual system. Adult male Long-Evans rats were either untreated or treated with malathion alone (two drops per day in each eye), bait alone (six drops per day in each eye) or malathion and bait (six drops per day in each eye). The dose levels of malathion alone and malathion and bait were chosen based on pilot work and provided approximately equivalent amounts of active ingredient. The rats were treated 5 days a week for 4 weeks. During the final week of treatment, the rats were implanted surgically with cranial recording electrodes overlying the visual projection area of the cerebral cortex. Visual pattern-evoked potentials (PEPs) were elicited with vertical sinusoidal gratings at three levels of stimulus spatial frequency (0. 08, 0.16 and 0.32 cycles per degree) and three levels of visual contrast (0.15, 0.30 and 0.60). After spectral analysis of the PEP waveforms, the amplitude and phase at the stimulus rate (F1) and the first harmonic (F2) were determined. Although F1 and F2 parameters were influenced significantly by manipulation of the stimulus parameters, no significant differences were observed that could be attributed to treatment with the test substances. In addition, an ophthalmological examination of the eyes and a light microscopic evaluation of ocular tissues, including retina and optic nerve, revealed no treatment-related lesions. The dose levels used in this study were high-approximately 84000 times the exposure per unit surface area expected from aerial spraying-and yet the visual function of the treated subjects was apparently normal. This study identified no significant toxicological concerns regarding direct ocular contact exposure to malathion.

Administration, Topical↗

PubMedDate not supplied

Bacteremia in connection with transurethral resection of the prostate.

A bacteriological survey of 50 consecutive patients undergoing transurethral resection of the prostate was performed. Preoperatively, 28% of the patients had asymptomatic bacteriuria. In the postoperative period, 46% of all the patients developed transient bacteremia. A significantly higher rate of bacteremia was found in patients with hypertrophy of the prostate than in those with cancer of the prostate and in patients undergoing long-lasting surgical intervention. Patients who developed bacteremia due to pathogenic bacteria were hospitalized for a significantly longer period of time.

Aged↗

PubMedDate not supplied

Algesia and local responses induced by neurokinin A and substance P in human skin and temporal muscle.

Neurokinin A (NKA), substance P (SP) and the two peptides combined (SP + NKA) were injected intracutaneously on the forearm and into the temporal muscle of healthy volunteers. Pain intensity, cutaneous wheal and flare responses and tenderness of the temporal muscle were quantitated. SP but not NKA induced cutaneous pain. This relates the algesic effect of SP to the specific N-terminal amino acid sequence of the peptide, not shared by NKA. NKA, however, potentiated the algesic effect of SP as SP + NKA induced a significantly prolonged cutaneous pain sensation. Both peptides induced wheals, but only SP induced flare. These results confirm previous studies relating wheal formation to the identical C-terminal amino acid sequence of the two peptides and flare reaction to the N-terminal part of SP. Injections into the temporal muscle did not cause pain or tenderness.

Adult↗

PubMedDate not supplied

Effect of neurokinin A on human temporal muscle blood flow.

The effect of neurokinin A on human temporal muscle blood flow was compared to saline when injected into the muscle in six normal subjects. The 133-Xenon washout technique was used and the test solutions administered in a double-blind, cross-over manner. Neurokinin A (0.02 ml, 10(-5)M) caused a blood flow increase of 193%, while saline caused an increase of 23%. The difference between neurokinin A and saline was significant (p less than 0.05). It is suggested that a possible pathophysiological role of neurokinin A in migraine must involve modulation of vascular response as well as of primary nociception.

Adult↗

PubMedDate not supplied

Pain and tenderness in human temporal muscle induced by bradykinin and 5-hydroxytryptamine.

Pain was induced in 19 healthy individuals by double-blind injections into the temporal muscle of 0.2 ml of physiological saline with or without active substances added. 5-Hydroxytryptamine (2 nmol) caused pain similar to saline, bradykinin (2 nmol) only insignificantly more pain (0.05 less than p less than 0.1), while a mixture of the two substances in half dosage (1 nmol + 1 nmol) caused pain significantly above saline (p less than 0.01). Variations in the response to saline did not permit a conclusion to be made on the question of induced tenderness. However, the mixture of the two substances appeared to lower the pressure-pain threshold as measured by a pressure algometer (p less than 0.05).

Adult↗

PubMedDate not supplied

Pain, wheal and flare in human forearm skin induced by bradykinin and 5-hydroxytryptamine.

Pain was induced in 19 healthy individuals by double-blind injections into the forearm skin of 0.05 ml of physiological saline with or without active substances added. Bradykinin (0.5 nmol), 5-hydroxytryptamine (0.5 nmol) and a mixture of the two substances in half dosage (0.25 nmol + 0.25 nmol) caused significantly more pain than saline (p less than 0.05). The three test solutions also induced wheal and flare responses significantly more pronounced than saline. Bradykinin induced significantly more pain and more wheal than 5-hydroxytryptamine (p less than 0.05) but a significantly smaller flare (p less than 0.01). A dissociation between induced pain and flare was thus demonstrated.

Adult↗

PubMedDate not supplied

Calcitonin gene-related peptide, neurokinin A and substance P: effects on nociception and neurogenic inflammation in human skin and temporal muscle.

Calcitonin gene-related peptide (CGRP) was injected alone and in combination with substance P (SP) or neurokinin A (NKA) into the forearm skin and temporal muscle of human volunteers. In the skin, 50 pmol of CGRP induced a wheal response and a delayed erythema. No pain was recorded. No interaction between CGRP and SP or NKA was observed. In the temporal muscle, 200 pmol of CGRP alone did not induce pain or tenderness but, in combination with SP or NKA, CGRP elicited a significant pain sensation. It is concluded that CGRP may be involved in neurogenic inflammation and that only SP, of the three peptides present in nociceptive C fibers, seems to be of major importance in relation to cutaneous nociception. Simultaneous neurogenic release of CGRP and other neuropeptides in skeletal muscle may induce myofascial pain.

Adult↗

PubMedDate not supplied

Depot medroxyprogesterone. Management of side-effects commonly associated with its contraceptive use.

Depot medroxyprogesterone acetate is one of the most popular, effective methods of contraception used in the United States. Many women experience unpleasant side effects from this method, including episodic vaginal bleeding, hair loss, depression, and weight gain. This Clinical Practice Exchange describes the treatment strategies for these side-effects used by nurse-midwives from a variety of settings and locales. Contraceptive use can be more acceptable for many women if they are better able to cope with unpleasant side effects of the method. This Clinical Practice Exchange provides knowledge to enhance client coping.

Adaptation, Psychological↗

PubMedDate not supplied

Rapid neurobehavioral analysis of Pfiesteria piscicida effects in juvenile and adult rats.

The estuarine dinoflagellate Pfiesteria piscicida is known to kill fish and has been associated with neurocognitive deficits in humans. We have developed a rat model to demonstrate that exposure to Pfiesteria causes significant learning impairments. This has been repeatedly seen as a choice accuracy impairment during radial-arm maze learning. Pfiesteria-induced effects were also seen in a locomotor activity test in the figure-8 apparatus. The current studies used the short-term radial-arm maze acquisition, the figure-8 activity test, and the functional observational battery (FOB) to assess Pfiesteria-induced neurobehavioral effects in adult and juvenile rats. In study 1, the neurobehavioral potency of three different Pfiesteria cultures (Pf 113, Pf 728, and Pf Vandermere) was assessed. Ninety-six (12 per group) adult female Sprague-Dawley rats were injected subcutaneously with a single dose of Pfiesteria taken from aquarium-cultured Pfiesteria (35,600 or 106,800 Pfiesteria cells per kilogram of rat body weight). One control group (N = 12) was injected with saline and one (N = 12) with aquarium water not containing Pfiesteria. All three of the Pfiesteria samples (p < 0.05) impaired choice accuracy over the first six sessions of training. At the time of the radial-arm maze choice accuracy impairment, no overt Pfiesteria-related effects were seen using an FOB, indicating that the Pfiesteria-induced choice accuracy deficit was not due to generalized debilitation. In the figure-8 apparatus, Pfiesteria treatment caused a significant decrease in mean locomotor activity. In study 2, the neurobehavioral effects of the Pf 728 sample type were assessed in juvenile rats. Twenty-four day-old male and female rats were injected with 35,600 or 106,800 Pf-728 Pfiesteria cells per kilogram of rat body weight. As with adult females, the juvenile rats showed a significant impairment in radial-arm maze choice accuracy. No changes in locomotor activity or the FOB were detected in the juvenile rats. Furthermore, there were no differences between male and female rats in the Pfiesteria-induced choice accuracy impairment. Pfiesteria effects on choice accuracy in the radial-arm maze in rats constitute a critical component of the model of Pfiesteria toxicity, because the hallmark of Pfiesteria toxicity in humans is cognitive dysfunction. Our finding that analysis of the first six sessions of radial-arm maze testing is sufficient for determining the effect means that this test will be useful as a rapid screen for identifying the critical neurotoxin(s) of Pfiesteria in future studies.

Aging↗