Wilson Rumbeiha - Academia.edu (original) (raw)

Papers by Wilson Rumbeiha

Accreditation and Quality Assurance

The Food and Drug Administration’s Veterinary Laboratory Investigation and Response Network is co... more The Food and Drug Administration’s Veterinary Laboratory Investigation and Response Network is comprised of more than 40 animal diagnostic laboratories within North America and offers voluntary Proficiency Exercises to these participating laboratories. The joint Proficiency Exercise Program is run in collaboration with the Center for Food safety and Nutrition and Institute for Food safety and Health, located at the Moffett Proficiency Testing Laboratory. From 2012 to 2018, the Proficiency Exercise Program offered 20 proficiency tests or interlaboratory comparison exercises focused on veterinary analytes of interest. The program evaluated performance of laboratories, individual analysts, and the methods used. Over the six-year period, the program improved exercise schemes, as well as offered network laboratories exercises with analytes not routinely seen such as animal tissue with naturally occurring residues. Animal diagnostic laboratories can use performance results to assist with ...

Quality and use of veterinary pharmaceuticals by pastoralists in the Far North Region of Cameroon... more Quality and use of veterinary pharmaceuticals by pastoralists in the Far North Region of Cameroon. (DOC 353 kb)

International Journal of Food Contamination, 2017

Background: The contamination of food by chemical hazards is a worldwide public health concern an... more Background: The contamination of food by chemical hazards is a worldwide public health concern and is a leading cause of trade problems internationally. Based on former work describing the prevalent use and misuse of antibiotics in cattle in the Far North Region of Cameroon, we designed a study to detect antibiotic (penicillin G and oxytetracycline) in beef sold for human consumption in Maroua (Cameroon). To determine the mean concentration of antibiotic residues in beef, sample of liver and muscle were collected from 202 cattle selected randomly in all the slaughterhouses of Maroua and Godola and analyzed using Liquid Chromatographic tandem Mass Spectrometry (LC-MS/MS). Characteristics of the cattle selected (age, sex, breed, body condition score, weight, production system, and pathology, etc.) were also collected before and/or after slaughterby physical examination and survey, and post mortem examination. Results: Results revealed that out of 202 cattle 41 (20.30%) tested positive for antibiotics in one or more of their organs. The meat of cattle from transhumance system, sick animals and older cattle was more likely to be contained with penicillin G and oxytetracycline residues. The average residues concentration in beef was 17.58 μg/ kg for penicillin G and 240 μg/kg for oxytetracycline. Conclusions: The findings of the present study should be alarming for the legislative authorities in food security and safety. This highlights a very serious problem, both for the consumers of Maroua city and the herders of the region as well as for the whole economy of Cameroon. It is therefore be important that measures be taken at several levels by the actors of the sector (public authorities, veterinary auxiliaries, etc.) to guarantee the safety of the food of animal origin.

Pastoralism, 2017

This study evaluates the quality of the veterinary drugs most frequently used in the Far North Re... more This study evaluates the quality of the veterinary drugs most frequently used in the Far North Region of Cameroon and describes how pastoralists use them to treat their cattle herds. High-performance liquid chromatography was used to identify and quantify the active ingredients in the drugs (penicillin G, levamisole, oxytetracycline, diminazene diaceturate, vitamin A, and vitamin E acetate) and gas chromatography mass spectrometry to determine if organic chemical contaminants were present. The results showed that 69% of surveyed pastoralists used veterinary medicines to treat common illnesses. In addition, the most commonly used medications (procaine penicillin G and oxytetracycline) were used in a manner inconsistent with the recommended dosage, frequency, duration, and withdrawal period by 98% of the pastoralists. However, contrary to previous studies, the quality of the medications used by pastoralists was generally good. The poor compliance with recommended treatment protocols was much more prevalent than use of poor quality medications and presents a potential for treatment failure, drug resistance of animal pathogens, and harmful drug residues in the human food supply, all of which have potentially negative consequences for animal and human health.

Cogent Food & Agriculture, 2016

Exposure to mercury contaminated fish predisposes populations particularly children and pregnant ... more Exposure to mercury contaminated fish predisposes populations particularly children and pregnant women to various health hazards including neurotoxicity, reproductive abnormalities and cognitive disorders. Earlier studies in the Lake Albert community have demonstrated the presence of mercury in Nile tilapia and Nile perch. However, the risk estimates for vulnerable groups such as Children and pregnant women is not well documented. Secondary data-set from previous studies were employed comprising family household size and fish consumption history, fish consumption quantity and frequency and mercury levels in fish species in comparison with FAO/WHO guidelines. Data collected was used to establish the hazard quotients (HQs) for the vulnerable group and the general population. A risk model was developed using iRISK to demonstrate the Disability Adjusted Life Years (DALYs) for eating different parts of the fish (muscle and bellyfat). HQ values (HQ = 2.05) above one for the vulnerable group were realized especially with Nile perch muscle. The highest DALYs (0.111) was obtained with tilapia muscle consumption. The study outcome reveals that vulnerable populations are at risk of non-carcinogenic complications. Therefore, there is a need for sensitization of the community especially the vulnerable groups about risks associated with consuming mercury-contaminated fish.

Annals of the New York Academy of Sciences, Jan 21, 2016

Hydrogen sulfide (H2 S), the gas with the odor of rotten eggs, was formally discovered in 1777, o... more Hydrogen sulfide (H2 S), the gas with the odor of rotten eggs, was formally discovered in 1777, over 239 years ago. For many years, it was considered an environmental pollutant and a health concern only in occupational settings. Recently, however, it was discovered that H2 S is produced endogenously and plays critical physiological roles as a gasotransmitter. Although at low physiological concentrations it is physiologically beneficial, exposure to high concentrations of H2 S is known to cause brain damage, leading to neurodegeneration and long-term neurological sequelae or death. Neurological sequelae include motor, behavioral, and cognitive deficits, which are incapacitating. Currently, there are concerns about accidental or malicious acute mass civilian exposure to H2 S. There is a major unmet need for an ideal neuroprotective treatment, for use in the field, in the event of mass civilian exposure to high H2 S concentrations. This review focuses on the neuropathology of high acut...

Toxins, May 21, 2016

Orellanine (OR) toxin is produced by mushrooms of the genus Cortinarius which grow in North Ameri... more Orellanine (OR) toxin is produced by mushrooms of the genus Cortinarius which grow in North America and in Europe. OR poisoning is characterized by severe oliguric acute renal failure, with a mortality rate of 10%-30%. Diagnosis of OR poisoning currently hinges on a history of ingestion of Cortinarius mushrooms and histopathology of renal biopsies. A key step in the diagnostic approach is analysis of tissues for OR. Currently, tissue-based analytical methods for OR are nonspecific and lack sensitivity. The objectives of this study were: (1) to develop definitive HPLC and LC-MS/MS tissue-based analytical methods for OR; and (2) to investigate toxicological effects of OR in mice. The HPLC limit of quantitation was 10 µg/g. For fortification levels of 15 µg/g to 50 µg/g OR in kidney, the relative standard deviation was between 1.3% and 9.8%, and accuracy was within 1.5% to 7.1%. A matrix-matched calibration curve was reproduced in this range with a correlation coefficient (r) of 0.97-0...

Veterinary Clinics of North America: Food Animal Practice, 2000

Journal of medical toxicology : official journal of the American College of Medical Toxicology, 2012

Stroke; a journal of cerebral circulation, 2013

An urgent need exists to develop therapies for stroke that have high efficacy, long therapeutic t... more An urgent need exists to develop therapies for stroke that have high efficacy, long therapeutic time windows, and acceptable toxicity. We undertook preclinical investigations of a novel therapeutic approach involving supplementation with carnosine, an endogenous pleiotropic dipeptide. Efficacy and safety of carnosine treatment was evaluated in rat models of permanent or transient middle cerebral artery occlusion. Mechanistic studies used primary neuronal/astrocytic cultures and ex vivo brain homogenates. Intravenous treatment with carnosine exhibited robust cerebroprotection in a dose-dependent manner, with long clinically relevant therapeutic time windows of 6 hours and 9 hours in transient and permanent models, respectively. Histological outcomes and functional improvements including motor and sensory deficits were sustained on 14th day poststroke onset. In safety and tolerability assessments, carnosine did not exhibit any evidence of adverse effects or toxicity. Moreover, histolo...

JAMA Pediatrics, 2013

, for a typographical error in the Methods section. 1. Section on Breastfeeding. Breastfeeding an... more , for a typographical error in the Methods section. 1. Section on Breastfeeding. Breastfeeding and the use of human milk.

Journal of Medical Toxicology, 2010

Commercial pet food in USA is generally safe, but adulteration does occur. Adulterated food has t... more Commercial pet food in USA is generally safe, but adulteration does occur. Adulterated food has to be recalled to protect pets and public health. All stakeholders, including food firms, distributors, and government agencies such as the Food and Drug Administration (FDA) participate in food recall. The objective of this review is to describe the pet food recall procedure from start to finish, and to review class I and II pet food recalls from 1996 to 2008, with a specific focus on those due to chemical contaminants/adulterants. Information was requested from the FDA by Freedom of Information Act. Only those recalls backed by the FDA scientific review were considered. The legal framework for food recalls in the Code of Federal Regulations, Title 21, Chapter 1, Part 7 and in the Food and Drug Administration Amendments Act of 2007, Title X was reviewed. From 1996 to 2008, there were a total of 22 class I and II pet food recalls. Of these, only six (27%) were due to chemical adulterants. The adulterants were aflatoxins, cholecalciferol, methionine, and melamine, and cyanuric acid. The causes of adulteration included inadequate testing of raw materials for toxins, use of wrong or faulty mixing equipment, and misformulation of raw materials. Overall, pet food manufactured in the USA is safe. Even with shortcomings in the recall process, the incidence of illness associated with pet food adulteration is low. Added changes can only make the system better in the future to safeguard pet and public safety.

Veterinary Clinics of North America: Small Animal Practice, 2002

Veterinary Clinics of North America: Food Animal Practice, 2012

The most common sources of ruminant poisoning are feed and water. Diagnoses are based on history,... more The most common sources of ruminant poisoning are feed and water. Diagnoses are based on history, clinical signs, lesions, laboratory examinations, and analytical chemistry. A complete history is necessary for developing the scheme of laboratory investigation and may be valuable in case of litigation. This article outlines the toxicology involved, as well as the procedures and analytic capability of the tests used for differential diagnosis in these cases.

Toxicology, 2000

Endotoxin (lipopolysaccharide; LPS) and mercury are compounds of food safety concern. Endotoxin i... more Endotoxin (lipopolysaccharide; LPS) and mercury are compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through infection plus translocation into circulation from the gastrointestinal tract. Food is the major source of mercury in humans. The toxic interaction between LPS and mercury has not been well investigated. In a previous study, we demonstrated that LPS potentiated mercury-induced nephrotoxicity in the rat. Whether this observation was species specific was not clear. In this study we tested the hypothesis that LPS enhances mercuric chloride (HgCl 2)-induced nephrotoxicity in mice. In a 2 × 2 factorial design, mice received either Escherichia coli 0128:B12 endotoxin (2.0 mg/kg body weight) or 200 ml of 0.9% sodium chloride (saline), and this was followed 4 h later by either mercury (1.75 mg mercuric chloride per kg body weight) or 200 ml of saline. Mice were monitored for 48 h. Monitored end-points included body and renal weights, urine volume, renal histology and ultrastructural pathology, serum urea nitrogen and creatinine, selected serum and urine cytokines, and renal mercury concentrations. Endotoxin by itself was not nephrotoxic at the dose used in this study. Overall, mice given LPS plus mercury were the most severely affected. Mice given LPS and mercury also had significantly greater renal mercury concentration than those given mercury alone (P5 0.05). In conclusion, LPS potentiates mercury-induced nephrotoxicity in the mouse.

Stroke, 2012

Background and Purpose— Asiatic acid (AA) has been shown to attenuate cerebral infarction in a mo... more Background and Purpose— Asiatic acid (AA) has been shown to attenuate cerebral infarction in a mouse model of focal ischemia and shows promise as a neuroprotective stroke therapy. To facilitate translation of these findings to clinical studies, we determined pharmacokinetics, a dose–response relationship, the therapeutic time window, and efficacy using multiple stroke models. We also explored potential mechanisms of action. Methods— Escalating doses of intravenous AA were administered and serum concentrations were measured at multiple time points for the pharmacokinetic studies. Subsequently, a dose–response relationship was determined followed by administration at different intervals after the onset of ischemia to establish a therapeutic time window for neuroprotection. Outcome measurements included both histological and behavioral. Mitochondrial function and matrix metalloproteinase activity in controls and treated rats were also determined. Results— The pharmacokinetic studies sh...

Rapid Communications in Mass Spectrometry, 2007

Antibiotics present in the environment are recently considered as emerging contaminants, and have... more Antibiotics present in the environment are recently considered as emerging contaminants, and have raised increasing concerns about their potential risks to ecosystems and human health. In addition to the utilization for treatment, antibiotics are also routinely added as supplements in livestock feed to promote animal growth. A portion of the administered dose used for these purposes can be excreted into animal manure, and land application of the animal manure as plant fertilizers enhances the dissemination of antibiotics in the environment. It is a common practice to simultaneously administer multiple classes of antibiotics to livestock in an animal production farm. This study attempts to develop a protocol to determine four commonly used veterinary pharmaceuticals, amprolium, carbadox, monensin, and tylosin, in surface runoff from a livestock farm. A single-cartridge solid-phase extraction procedure was developed to simultaneously extract these veterinary antibiotics from surface water which were subsequently analyzed by liquid chromatography/tandem mass spectrometry. The extraction recoveries of spiked samples ranged from 89 to 113%, and the limits of quantitation were 8, 25, 1, and 35 ng/L for amprolium, carbodox, monensin, and tylosin, respectively. In the surface runoff from a livestock farm, amprolium was most frequently detected with the concentration range of 10-288 ng/L. Monensin was frequently detected with concentrations up to 37 ng/L. Tylosin was detected in two out of eleven samples, and carbadox was not detected in the surface runoff. The results indicate that the developed analytical method can be utilized to determine multiple classes of veterinary antibiotics present in surface runoff originating from animal farms.

Life Sciences, 2004

Easter lily (Lilium longiflorum) flowers have been used in traditional medicine for alleviating m... more Easter lily (Lilium longiflorum) flowers have been used in traditional medicine for alleviating many ailments. However, the chemical basis of its bioactivity has not been investigated. We have determined bioactive components in Easter lily flowers using lipid peroxidation and cyclooxygenase enzyme inhibitory assays and found to be kaempferol (1), kaempferol glycosides (2, 3, 4, 8, 9 and 10), quercetin glycosides (5, 6 and 7), a regaloside (11), a chalcone (12) and a fatty acid fraction (13). The structures of compounds were determined by NMR, IR, UV/VIS and mass spectroscopic studies. Compound 1 showed the highest COX-1 inhibition (94.1%) followed by 3, 8 and 12 with 38.7, 30.8 and 32.4%, respectively. Only compound 1 inhibited COX-2 enzyme by 36.9% at 80 ppm. In lipid peroxidation inhibitory assay, kaempferol showed 37 and 100 % inhibitions at 1 and 10 ppm, respectively. At 10 ppm, more than 20% inhibition was observed for compounds 4, 7, 10, 11 and 12 and 53% for compound 3. The compounds reported in here are isolated for the first time from Easter lily flowers including novel compounds 10, 11 and 12. Our results suggest that kaempferol and quercetin flavonoids contributed to the anecdotal medicinal properties of Easter lily flowers.

Journal of Zoo and Wildlife Medicine, 2007

Complete physical examinations and biomedical sample collection were performed on 70 free-ranging... more Complete physical examinations and biomedical sample collection were performed on 70 free-ranging ring-tailed lemurs (Lemur catta) from three different habitats in the Beza Mahfaly Special Reserve (BMSR), in southern Madagascar, to assess the impact of humans and habitat on lemur health. Lemurs were chemically immobilized with ketamine and diazepam administered via blow darts for concurrent biomedical, morphometric, and behavioral studies. Subsets of the animals had blood analyzed for hematology, serum chemistry, micronutrients, fat-soluble vitamins (vitamins A, D, and E), measures of iron metabolism, and polymerase chain reaction assays (PCR) for Toxoplasma gondii, Hemoplasma spp., Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, and Neorickettsia risticii. Results were compared on the basis of gender and the habitats at the study site: reserve (intact gallery forest), degraded (human inhabited and altered), and marginal (dry didieracea forest with heavy grazing and tree cutting). Levels of vitamin D, triglycerides, and cholesterol, and measures of iron metabolism for BMSR lemurs were greater than those previously reported for a free-ranging lemur population (Tsimanampetsotsa Strict Nature Reserve, Madagascar) with less access to foods of anthropogenic origin. BMSR ring-tailed lemurs from a habitat with less water (marginal) had higher sodium (P ϭ 0.051), chloride (P ϭ 0.045), osmolality (P ϭ 0.010), and amylase (P ϭ 0.05) levels than lemurs from other BMSR habitats, suggesting that these lemurs were less hydrated. Vitamin D levels of male lemurs were higher (P ϭ 0.011) than those of females at BMSR, possibly because of differences in sunning behavior or differential selection of food items. The biological significance is uncertain for other parameters with statistically significant differences. All samples tested (n ϭ 20) were negative for the pathogens tested using PCR assays. Continued concurrent biomedical and ecological research is needed at BMSR to confirm these results and determine their association with population mortality and fecundity rates.