Lipophilin-induced experimental allergic encephalomyelitis in guinea pigs

Clinical signs of EAE were infrequently observed (1/20) in adult Hartley guinea pigs challenged with isolated human myelin lipophilin in complete Freund's adjuvant. However, CNS vasculitis and parenchymal infiltration by inflammatory cells were found in 10 of 20 inoculated animals. Localized, nonconfluent, small demyelinated lesions were detected in the brain and spinal cord of 5/20 Hartley guinea pigs during an observation period of 120 days. The frequency of both inflammatory and demyelinated lesions in Hartley animals appeared to be dosedependent, but extensive demyelinated lesions were not induced. Persistent residual inoculation mixture at the site of injection was found in animals showing CNS inflammatory and/or demyelinated lesions. In contrast to the Hartley strain, young strain 13 guinea pigs were clincally and pathologically unresponsive to challenge with lipophilin and mycobacteria in water-in-oil emulsion.     

Histological evaluation of cochlear blood flow using different fixation methods

Summary For an accurate histological evaluation of cochlear blood flow, it is essential to fix the cochlear vessels while maintaining their physiological state. In the present study, we administered 10% CO₂ to guinea pigs and then used phase-contrast microscopy to determine how two different methods of fixation influenced the cochlear vasculature. The first method of fixation employed perilymphatic perfusion in vivo, while the second one involved fixation after decapitation. Decapitation caused significant changes in the vessels of the stria vascularis, including constriction and sludging. In contrast, no sludging occurred in the perilymphatic perfusion method and erythrocyte morphology was preserved. However, dilatation of the strial blood vessels occurred after the inhalation of 10% CO₂ even in the decapitation method. The results demonstrate that particular attention must be paid to the fixation method used, especially when evaluating the blood flow of the stria vascularis.     

The irreversible narcotic antagonistic and reversible agonistic properties of the fumaramate methyl ester derivative of naltrexone

The fumaramate methyl ester derivatives of naltrexone (β-FNA) and oxymorphone (β-FOA) were both found to be reversible agonists on the guinea pig ileal longitudinal muscle preparation. In addition, β-FNA possessed an irreversible antagonistic effect against morphine whereas β-FOA had no such capacity. Analysis by pA₂ values revealed that β-FOa resembled pure agonists like morphine and enkephalin while β-FNA resembled the mixed agonist-antagonists like nalorphine and pentazocine. The antagonism by β-FNA was very selective in that it antagonized pure agonists but had little or no effect on the effects of either mixed agonists, ethylketocyclazocine or other non-opiate-type agonists like norepinephrine.     

Experimental infection of the guinea pig inner ear with toxoplasma gondii

Summary Based on the question whether toxoplasma gondii is a potential pathogenetic factor in sudden deafness and vertigo (especially in the acquired form of Toxoplasmosis) we started a series of investigations, dealing with direct, local, hematogenous, and intracisternal infection of the guinea pig cochlea with toxoplasma gondii.Three of ten directly inoculated and one of five hematogenously infected guinea pigs showed a severe labyrinthitis in electron and light microscopy.Thus, we could demonstrate that toxoplasma gondii is a potent pathogenetic factor in acute inner ear disturbances in laboratory animals. Toxoplasmosis should always be considered in cases with sudden deafness and vertigo without obvious other cause. With a specific therapy the labyrinthine disturbances can apparently be successfully treated.     

Dietary fish oil alters the sensitivity of guinea pig ileum to electrically driven contractions and 8-iso-PGE2

Dietary fish oil rich in n-3 polyunsaturated fatty acids (PUFA) have been positively implicated in bowel health. This was investigated in relation to newborn guinea pig growth, caecal digesta pH and SCFA profile, ileal total phospholipid fatty acid content and particularly for in vitro ileal contractility. A newly formulated commercial rice porridge (congee) preparation supplemented with essential nutrients, standard chow for palatability and 3% fat as safflower oil or tuna fish oil was fed to new born guinea pigs and their mothers. After two months of feeding, while the mean body weight and weight and length of small intestine of the fish oil supplemented group were significantly lower (P < 0.05) compared to the safflower supplemented group there was no difference in final small intestine density. Substitution of safflower oil with tuna fish oil led to significantly lower oleic acid content of ileum total phospholipid with a concomitant increase in the n-3 PUFA ALA, EPA and DHA (P < 0.05). The fish oil supplemented group had a significantly higher caecal digesta pH (P < 0.03) with a significantly lower propionate concentration (P < 0.04). Significantly less voltage was required to initiate contraction of the ileum of the fish oil supplemented group (P < 0.03). There was no significant difference in the sensitivity (EC₅₀) and maximal contraction induced by acetylcholine, histamine, serotonin, and prostaglandins PGE₂ or PGF₂. However, the sensitivity to the isoprostane, 8-iso-PGE₂ of the fish oil supplemented group was significantly reduced (P < 0.04). These results warrant further investigation into the physiological role that dietary n-3 PUFA may play in bowel contractility and health.     

A survey of dental disease in children of Wuvulu Island, Papua New Guinea

A convenience sample of 153 boys and girls, aged 3-16 years, inhabiting Wuvulu Island were examined for the prevalence of dental caries and periodontal disease and for oral hygiene status. Average of teeth and surface scores for the group were 2.08 and 3.35, respectively, while average DMF teeth and surface scores were 0.90 and 1.20, respectively. Of the sample, 30.7% were caries free. Oral hygiene was poor and males had significantly more periodontal disease than females. While primary teeth were about three times more susceptible to caries than permanent teeth, tooth loss due to caries was not a problem in primary teeth. The authors discuss findings of other researchers and reasons for the greater prevalence of caries in primary teeth.     

Die fungistatische Wirkung von diäthanoloaminhaltigem Gel unter in vivo Bedingungen: A Fungistatic Effect of Diethanoloamine Gel Preparation under in vivo Conditions

Zusammenfassung: Zur Behandlung einer bei Meerschweinchen durch Trichophyton mentagrophytes hervorgerufenen Trichophytie wurde ein 10% diäthanoloaminhaltiges Präparat in Gelform angewandt. Als Kontrollgruppe dienten Tiere die mit Canesten-Creme behandelt wurden. Sowohl klinische Beobachtungen als auch mykologische und histopathologische Befunde bestätigen die therapeutische Wirksamkeit von Diäthanoloamin.
Summary: A 10% diethanoloamine gel preparation was used to treat an experimental trichophytosis of guinea pigs challenged by Trichophyton mentagrophytes. The control group was made up by animals treated with Canesten creme. Clinical observations, as well as mycologic and histopathologic studies have confirmed the therapeutic effectiveness of diethanoloamin.     

Specific activity and sensitivity to strophanthin of the Na+ + K+-activated ATPase in rats and guinea-pigs with hypoadrenalism

Summary In adrenalectomised rats and in guinea-pigs pretreated with metyrapone the specific activity of the Na⁺ + K⁺-stimulated ATPase of heart and kidney is significantly diminished, whereas the activity of the Mg⁺⁺-ATPase remains unchanged. The specific activity of the Na⁺ + K⁺-stimulated ATPase from brain tissue is not influenced by either adrenalectomy or by treatment with metyrapone.The sensitivity of the Na⁺ + K⁺-stimulated ATPase of heart, brain and kidney to k-strophanthin remains unchanged by adrenalectomy or by treatment with metyrapone.Supported by the Deutsche Forschungsgemeinschaft (SFB 30, Kardiologie).     

Effects of Adrenergic P-Blockers and a Membrane Stabilizing Agent on Ouabain-Induced Cardiac Arrhythmias in Anaesthetized Guinea Pigs

Abstract The antiarrhythmic effects of dl-propranolol, d-propranolol, metoprolol and lidocaine against ouabain-induced cardiac arrhythmias were studied. It was found that contrary to earlier findings in the dog, the effects of the adrenergic β-blockers against ouabain-arrhythmias in guinea pigs were due to β-blocking activity and not the membrane-stabilizing activity of the compounds. The cardioselective β-blocker, metoprolol, was more or equally effective as dl-propranolol against ouabain-induced arrhythmias in guinea pigs.