Double-blind, vehicle-controlled randomized twelve-month neurodevelopmental toxicity study of common aluminum salts in the rat.

This good laboratory practice (GLP) study of aluminum salts in Sprague-Dawley rats was conducted according to double-blind, vehicle-controlled randomized design by exposing offspring to aluminum citrate in-utero, through lactation, and then in drinking water post-weaning. Three dose levels were used: 30, 100, 300 mg Al/kg bw/day, in addition to control groups that received either water or a sodium citrate solution (27.2 g/L). Endpoints were assessed in both female and male pups: behavioral (motor activity, T-maze, auditory startle, the Functional Observational Battery (FOB) with domains targeting autonomic function, activity, neuromuscular function, sensimotor function, and physiological function), cognitive function (Morris swim maze), brain weight, clinical chemistry, hematology, tissue/blood levels of aluminum and neuropathology. The most notable treatment-related effect observed in the offspring was renal pathology, most prominently in the male pups. Higher mortality and significant morbidity were observed in the male pups in the high Al-citrate dose group; leading to euthanization of this group at day 89. There was evidence for dose-response relationships between neuromuscular measurements-hind-limb and fore-limb grip strength-and Al-treatment in both males and females, although some of the effects may be secondary to body weight changes. No consistent treatment-related effects were observed in ambulatory counts (motor activity) in the different cohorts. No significant effects were observed for the auditory startle response, T-maze tests (pre-weaning day 23 cohort) or the Morris water maze test (day 120 cohort). None of the lesions seen on histopathological examination of brain tissues of the day 364 group was reported as treatment-related and, as these were also seen in the control group, were likely due to aging. In conclusion, these results indicate that concentrations of aluminum in the drinking water that are required to produce minimally detectable neurobiological effects in the rat are about 10,000 times higher than what is typically found in potable drinking water.

Addressing vitamin D deficiency in Canada: a public health innovation whose time has come.

There is disturbing evidence of widespread vitamin D deficiency in many population groups, particularly within nations at high latitude. Numerous recent studies in the scientific literature associate vitamin D deficiency with a colossal increase in morbidity and mortality. Since Canada is at higher latitude, this review assesses the vitamin D status within the Canadian population. This review was prepared by assessing available medical and scientific literature from Medline, as well as by reviewing several books and conference proceedings. A standard 25(OH)D level of 75-80nmol/l or more was used to indicate vitamin D sufficiency. Between 70% and 97% of Canadians demonstrate vitamin D insufficiency. Furthermore, studies assessing 25(OH)D levels of vitamin D at 25-40nmol/l reveal that many Canadians have profoundly deficient levels. Repletion of vitamin D3 with 2000IU/day for those not receiving judicious sun exposure and those with no contra-indications would likely achieve normalized levels in more than 93% of patients, without risk of toxicity. Explicit directives regarding vitamin D assessment and management are urgently required.

Early cervical cancer and parametrial involvement: is it significant?

OBJECTIVE: To determine the incidence of parametrial involvement in clinical stage IA and IB1 cervical cancer and whether pelvic lymph node status is a predictor of parametrial status. METHODS: Retrospective review of 120 patients with FIGO stage IA/IB1 cervical carcinoma treated by class II radical abdominal hysterectomy between January 1997 and December 2001 was performed. The parametria were examined for microscopic involvement of parametrial lymph nodes and/or tissue. Continuous variables were compared using Wilcoxon rank sum test, and Fisher's exact test was used to categorical variables. Kaplan-Meier curves were constructed for overall survival (OS) and recurrence-free survival (RFS). Cox proportional hazards model was used to investigate prognostic factors. RESULTS: One hundred ten patients were eligible. Five patients (5%) had positive parametria and 13 patients (12%) had positive pelvic lymph nodes. Four (80%) patients with positive parametria had positive pelvic lymph nodes. The groups did not differ significantly in terms of age (P = 0.92), histology (P = 0.15), or LVSI (P = 0.20). Positive parametria was associated with larger tumor size (3.0 vs. 2.0 cm, P < 0.05), greater depth of invasion (16 mm vs. 5 mm, P = 0.03), and pelvic lymph node metastases (80% vs. 10%, P = 0.001). The only variable that was significant in the proportional hazards model was lymph node status (P = 0.02). After median follow-up of 48 months, there was a significant difference in recurrence (40% vs. 4%, P = 0.03) and RFS (0.0003). CONCLUSIONS: Acknowledging small sample size and retrospective study, positive parametrial involvement in stage IA and IB1 cervical cancer is infrequent. There is a significant association with lymph node status. Thus, there may be a role for less radical surgery combined with pelvic lymphadenectomy in this patient population.

Effects of crude oil and diesel exposures on biochemical activities of polymorphonuclear leukocytes in cattle.

Cattle exposed to low doses of an Alberta crude oil, Pembina Cardium crude oil (PCCO), or a winter diesel oil no. 2 (WDO-2) were assessed for their biochemical activities in polymorphonuclear leukocyte (PMNL) cells (mainly neutrophils). The study used a randomized block design containing five treatment groups (8 animals/group). The animals were dosed per gavage with the test substance on study days 0, 14, 28, and 42. The dosages given (on per kg body weight) were: Group 1 (control), 10 mL/kg of potable water; Group 2, 5 mL/kg WDO-2; Group 3, 2.5 mL/kg PCCO; Group 4, 5 mL/kg PCCO; and Group 5, 10 mL/kg PCCO. Blood was collected at the specified intervals during the pre- and post-exposure periods, and the biochemical activities of isolated PMNL were analyzed. Cattle groups exposed to WDO-2 and PCCO showed moderate and statistically significant reductions (p < 0.01) in the activities of (1) phorbol myristate acetate (PMA) stimulated cellular respiration (respiratory burst), (2) NADPH-oxidase (PMA-stimulated production of superoxide anion), (3) myeloperoxidase, and (4) n-acetylglucosidase as compared to the control group. These biochemical parameters also showed statistically significant (p < 0.01) dose-related periodic (study day) trends. In general, these biochemical activities were decreased after each dosing; however, they subsequently recovered to near the pre-dosing levels. Such a biochemical response in PMNL provides a valuable biological tool to follow exposure effects in cattle accidentally exposed to low doses of petroleum hydrocarbons.

Inhibition of IL-1 beta-induced peripheral inflammation by peripheral and central administration of analogs of the neuropeptide alpha-MSH.

Interleukin-1 (IL-1) is a proinflammatory cytokine, alpha-MSH(1-13) molecules inhibit inflammation induced by cytokines, other mediators of inflammation, and by peripheral irritants. D-valine substitution in the antiinflammatory/antipyretic message sequence [alpha-MSH(11-13), Lys-Pro-Val] of alpha-MSH(1-13) increases the activity of the tripeptide. Our aim was to learn if D-valine substitution also enhances the antiinflammatory activity of the entire alpha-MSH(1-13) molecule and to determine if an antipyretic D-valine-substituted alpha-MSH(8-13) molecule is also antiinflammatory. Intraperitoneal injection of alpha-MSH(1-13) and of (D-Val13)alpha-MSH(1-13) caused dose-related suppression of ear edema induced in mice by intradermal injection of IL-1 beta; the two molecules were equipotent. (D-Val13)alpha-MSH(8-13) likewise inhibited inflammation, but the potency was less than that of the larger molecules. Intracerebroventricular injections of (D-Val13)alpha-MSH(1-13) and of the unsubstituted molecule were equipotent in reducing inflammation; the (D-Val13)alpha-MSH(8-13) molecule was less effective. The results support the idea that the alpha-MSH(1-13) molecule inhibits inflammation and suggest that the L-conformation of alpha-MSH(1-13) is maximally effective with regard to its antiinflammatory activity. The results with alpha-MSH(8-13) are consistent with previous findings of lesser antihost response activity of alpha-MSH fragments that contain the COOH-terminal tripeptide Lys-Pro-Val.

Alpha-MSH peptides inhibit acute inflammation induced in mice by rIL-1 beta, rIL-6, rTNF-alpha and endogenous pyrogen but not that caused by LTB4, PAF and rIL-8.

The neuropeptide alpha-melanocyte stimulating hormone [alpha-MSH(1-13)] occurs in the pituitary, brain, skin and other tissues and receptors for this molecule are likewise widespread. In previous research, this tridecapeptide, which shares its amino acid sequence with ACTH(1-13), was shown to have both potent antipyretic activity and a role in the endogenous control of the febrile response. alpha-MSH(1-13) and its COOH-terminal tripeptide were subsequently found to inhibit inflammation induced by general stimuli such as topical application of an irritant. The aim in the present experiments was to determine if these peptides can inhibit acute inflammatory responses induced in mice by injection of individual cytokines, endogenous pyrogen (EP), a natural cytokine mixture, and other mediators of inflammation. Inflammation induced in the mouse ear by rIL-1 beta, rIL-6 or rTNF-alpha was inhibited by alpha-MSH and a D-valine-substituted analog of alpha-MSH(11-13) whereas substantial doses of alpha-MSH(1-13) did not alter inflammation induced by LTB4, PAF and IL-8. Both peptides inhibited edema caused in the mouse paw by local injection of EP. The results indicate that alpha-MSH molecules antagonize the actions of certain cytokine mediators of inflammation, consistent with previous observations of anti-cytokine activity of these peptides. Failure to inhibit edema caused by LTB4, PAF and IL-8 suggests that, in inflammation induced by general stimuli, such as EP, the peptides act prior to the release of these mediators of the inflammatory response. Because of the anticytokine/anti-inflammatory actions of the alpha-MSH molecules they may be useful in understanding the cytokine network and for treatment of inflammatory diseases.

Inhibition of acute inflammation in the periphery by central action of salicylates.

Understanding of the antiinflammatory actions of nonsteroidal drugs is incomplete, but these actions are believed to occur in the periphery, without any contribution from the central nervous system. Recent research on the antipyretic antiinflammatory neuropeptide alpha-melanocyte-stimulating hormone indicates that it can act centrally to inhibit peripheral inflammation; this raises the possibility that other agents, such as nonsteroidal antiinflammatory drugs, may have similar activity. In the present research both lysine acetylsalicylate and sodium salicylate inhibited edema, induced in the mouse ear by topical application of picryl chloride, when injected into the lateral cerebral ventricle. This inhibitory activity on a measure of acute inflammation was not due to escape of the drugs into the periphery, because systemic injection of doses that were effective centrally did not affect inflammation. In contrast, central administration of a dose of indomethacin that was antiinflammatory when given intraperitoneally did not inhibit peripheral inflammation. Thus indomethacin apparently lacks the central antiinflammatory action of the salicylates. This observation, plus our inability to demonstrate either an antiinflammatory effect of intracerebroventricular dexamethasone, a prostaglandin inhibitor, or a pro-inflammatory influence of prostaglandin E2, suggests that prostaglandins are not important to central modulation of inflammation. The results indicate that, in addition to having central influences on fever and pain, salicylates can act within the brain to inhibit acute inflammation in the periphery.

Anti-inflammatory activity of alpha-MSH(11-13) analogs: influences of alteration in stereochemistry.

D-Amino acid substitutions in the anti-inflammatory/antipyretic Ac-alpha-MSH(11-13)-NH2 tripeptide of Ac-alpha-MSH(1-13)-NH2 were made and the altered peptides were injected in mice treated with picryl chloride. Ear swelling, measured 3 and 6 h after application of the irritant, was reduced by IP injections of Ac-alpha-MSH(11-13)-NH2, in confirmation of previous observations. Ac-[D-Lys11]alpha-MSH(11-13)-NH2 effected similar anti-inflammatory activity but Ac-[D-Pro12]alpha-MSH(11-13)-NH2 was inactive. Ac-[D-Val13]alpha-MSH(11-13)-NH2 and Ac-[D-Lys11,D-Val13]alpha-MSH(11-13)-NH2 generally had greater anti-inflammatory activity than the parent tripeptide molecule; the dose-response relations exhibited the bell-shaped characteristics seen previously with MSH peptides. The results indicate that the L-Pro12 is essential for the anti-inflammatory activity of Ac-alpha-MSH(11-13)-NH2 whereas the L-Lys11 is not. D-Val13 substitution increased anti-inflammatory activity approximately four-fold over Ac-alpha-MSH(11-13)-NH2. These results provide new structure-activity relationships of the anti-inflammatory Ac-alpha-MSH(11-13)-NH2 molecule. The data support the developing idea that alpha-MSH and its COOH-terminal fragments modulate host responses, perhaps by antagonizing the actions of cytokines.

Central administration of the peptide alpha-MSH inhibits inflammation in the skin.

Inflammation is generally conceptualized in terms of cells, mediators, and events in the periphery, with no consideration of an influence of the central nervous system (CNS). However, the neuroendocrine peptide alpha-melanocyte stimulating hormone (alpha-MSH) is anti-inflammatory when given systemically and this molecule reaches the brain to exert another effect: fever reduction. Tests on mice indicate that alpha-MSH can act solely within the CNS to inhibit inflammation in the skin. This observation indicates that the central nervous system can inhibit peripheral inflammation via action of alpha-MSH molecules and it further strengthens the idea of neural/endocrine modulation of the host responses.

Neuropeptide alpha-MSH antagonizes IL-6- and TNF-induced fever.

The pro-opiomelanocortin-derived peptide melanocyte stimulating hormone (alpha-MSH) antagonizes the fever induced by several stimuli including endotoxin, endogenous pyrogen, and certain cytokines. To determine if alpha-MSH can antagonize the pyrogenic action of recombinant IL-6 and TNF directly within the central nervous system, the cytokines were injected with and without alpha-MSH (200 ng) into a lateral cerebral ventricle of rabbits and rectal temperature was monitored continuously. Central administration of both cytokines caused fever. However, when alpha-MSH was injected after cytokine administration, the fevers were markedly reduced. The results are consistent with previous observations on the antipyretic effect of alpha-MSH and they show that the peptide can act within the brain to antagonize pyrogenic actions of specific cytokines believed to be important in CNS mediation of fever.

Alpha-MSH peptides inhibit acute inflammation and contact sensitivity.

Alpha-melanocyte stimulating hormone [alpha-MSH(1-13)] occurs within the CNS, skin, circulation and in other body sites. This tridecapeptide and its COOH-terminal tripeptide, alpha-MSH (11-13), have antipyretic and anti-inflammatory actions. Studies of the anti-inflammatory effects of these molecules have been confined mainly to tests of inhibition of histamine and endogenous pyrogen-induced increases in capillary permeability in rabbits and acute inflammation of ear tissue in mice. The aim in the present experiments was to learn if alpha-MSH peptides also antagonize inflammation in two additional models: acute edema induced in the mouse paw and contact sensitivity. Significant anti-inflammatory effects were observed with MSH peptides in both models. These findings converge with previous results to indicate that alpha-MSH peptides modulate inflammation. Because circulating alpha-MSH increases after treatment of animals with endogenous pyrogen or endotoxin, administration of the peptides may simply mimic a naturally occurring modulation of host defense reactions.

Antiinflammatory activity of a COOH-terminal fragment of the neuropeptide alpha-MSH.

The endogenous neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH 1-13), previously found to have marked antipyretic activity, inhibits histamine-induced increases in vasopermeability. The primary antipyretic amino acid message sequence is believed to be the COOH-terminal trieptide, lysine-proline-valine. In recent preliminary research this tripeptide inhibited increases in vasopermeability, raising the possibility that this portion of the alpha-MSH molecule has general antiinflammatory activity. To test this idea, the effects of graded doses of alpha-MSH [11-13] on ear swelling induced by picryl chloride in mice were compared with the effects of saline and a large dose of corticosteroid. Alpha-MSH [11-13] inhibited swelling in a dose-related fashion. This result, together with previous findings, suggests that endogenous circulating alpha-MSH and its COOH-terminal fragments may contribute to modulation of physiological responses in host defense. If this is true, it may be possible to develop new peptide drugs or mimetics based on the tripeptide that are useful in treating inflammation.