Detection of histamine and tyramine in some cheese

The biogenic amines content of various food has been widely studied because of their potential toxicity. This study aims at presenting data about histamine and tyramine content in some locally and imported soft, hard, and semihard cheese available in Alexandria markets throwing lights on its public health hazard. A total of 140 random cheese samples included a large variety of types of soft cheese [kareish, old cheese [Mish], Demietta], .Semihard cheese, [Roquefort and Gouda], and hard cheese [Ras and Cheddar] as twenty samples of each were analysed for histamine and tyramine using high performance liquid chromatography [HPLC]. Results showed that histamine and tyramine were detected in [35 - 55%] and [70-100%] of samples, respectively. All examined samples contained histamine level lower than the critical oral dose toxic to human [100 mg/i 00 g]. Tyramine exceeded the dangerous dose for patients receiving MAOI, [6 mg] by the percentage of [30, 100, 60, 100, 50, 80, and 60%], respectively. Histamin concentration increased in the order of cheddar> Mish> Gouda>Demietta> Ras> Roquefort> Kareish cheese. Also, tyramine increased in these manner Roquefort > Cheddar > Mish > Demietta > Gouda > Kariesh. The highest level of histamine and tyramine [20.46 +/- 7.73 and 32.76 +/- 1 0.32 mg/100g] recorded in cheddar and Roquefort cheese, respectively but the lowest level showed in kareish cheese [4.02 +/- 1.74 and 7.12 +/- 3.75 mg/100 g] of histamine and tyramine, respectively

Study of histamine wheal suppression by dexamethasone with and without iontophoresis.

BACKGROUND: Iontophoresis increases the penetration of drugs into the skin by electric current. The ability of topical steroids to reduce the size of the histamine wheal was used to assess the efficacy of topical dexamethasone delivered with and without iontophoresis. AIM: To determine the wheal suppressing ability of dexamethasone delivered with and without iontophoresis. METHODS: A template with three squares of 3x3 cm was placed on both forearms of 20 volunteers and the edges marked. A gauze piece soaked in 2 ml of dexamethasone solution was placed on the flexor aspect of the left forearm and the electrode, an aluminum foil was placed on it and connected to the negative pole (since dexamethasone is negatively charged). An electric current was passed for 15 minutes. Similarly, on the right forearm, a dexamethasone soaked gauze piece was placed without iontophoresis. Histamine wheal suppression was assessed at the end of 30 min, 1 hr and 2 hrs, on both sides. Statistical analysis was done using an independent t-test. RESULTS: There was a statistically significant difference in wheal suppression at 30 min (p=0.006) on the left hand where iontophoresis was used. CONCLUSION: Our experiment showed that topical dexamethasone with iontophoresis has the maximum effect at the end of 30 minutes and is more effective than dexamethasone without iontophoresis.