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Biomedical subjects

J F Griffith

Publications and source records attributed to J F Griffith.

At least 19 recordsLinked to original sources
PubMed1990

Evaluation of modified methods for determining skin irritation.

The premarket testing of household cleaning products for dermal irritancy is best achieved via human testing. Animal dermal irritation testing is generally limited to screening for possible dermal hazard of totally new or unique products or ingredients prior to human testing or to meeting regulatory requirements of government bodies. Alternatives to animal tests are being sought; however, until such time that these alternatives are identified, validated, and accepted by government bodies, the judicious use of animal testing remains a necessity. Modifications to standard animal skin irritation test procedures have been evaluated against human skin irritation results with the objective of defining one method that could be used in place of current standard procedures that differ slightly from one another, and thereby avoid excessive and redundant use of animals. Hill Top Chambers (19 mm) and standard gauze patches (U.S. Department of Transportation procedure) were used to obtain comparative irritation responses for 24 cleaning products, common caustics, and acids in rabbits and humans. Exposure times were 1 or 4 hr, and responses were graded over a 72-hr period. Results indicate that use of the Chamber offers the potential to (1) reduce the number of animals used for skin irritation screening (smaller group size and up to eight test substances/concentrations per animal); (2) eliminate the need for conducting multiple tests to satisfy different governmental requirements; and (3) reduce animal stress by reducing exposure times without compromising the value of the irritancy patch test as a screening tool. When animal data are required, it is suggested that the use of a Chamber and other modifications of traditional test procedures offers advantages that could result in using fewer animals and/or have less potential for producing unnecessarily severe responses in animals.

Animals↗
PubMed1986

Human and rabbit eye responses to chemical insult.

Groups of eight human volunteers and eight albino rabbits, under controlled laboratory conditions, were exposed in one eye without subsequent rinsing to the same concentrations and volumes of four prototype consumer products: fabric softener, shampoo, hand soap, and laundry detergent. Dose volume was 0.10 or 0.01 ml. The dose concentrations were selected to produce moderate effects with recovery within 24 to 48 hr. Two irritation scales were employed with both human and animal subjects: the Draize scale by a technician and a medical scale used with slit lamp examination by an ophthalmologist. Eyes were examined by both graders before and after dosing at specified intervals until recovery. Mean and maximum irritation scores are presented for each grading time, method, and exposure, as are the mean hours to recovery (clearing) for each exposure. Recovery times for human eyes were consistent with those reported previously for accidental human exposures to similar materials. Correlation coefficients for time to clear, comparing human vs rabbit for each dose volume-species combination across the four test products, were 0.72, 0.1 ml-human vs 0.01 ml-rabbit; 0.66, 0.01 ml-human vs 0.01 ml-rabbit; 0.40, 0.01 ml-human vs 0.1 ml-rabbit; 0.35, 0.1 ml-human vs 0.1 ml-rabbit. Thus, recovery time obtained under conditions of the "Low-Volume" test (0.01 ml-rabbit) better correlates with human eye recovery time (either dose volume) than does recovery time under Draize test conditions (0.10 ml-rabbit).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Myoclonus epilepsy in two brothers. Clinical features and neuropathology of a unique syndrome.

We report 2 brothers with progressive ataxia, seizures, myoclonus, supranuclear ophthalmoplegia, progressive visual loss and embolic strokes. The epilepsy and myoclonus came on many years after the onset of the ataxia. In the more severely affected brother the myoclonus was often unilateral and focal but ultimately involved both sides of the body. His sibling had only unilateral myoclonus after a contralateral middle cerebral artery stroke. When focal, persistent and unilateral, the myoclonus in both brothers was clinically similar to epilepsia partialis continua except that muscles of the trunk and proximal limbs were the most affected. It was exacerbated by movement of the affected part but was otherwise not stimulus sensitive. The more severely affected brother had a pigmentary retinopathy and a cardiac fibromyxoid valvulopathy. In his sibling, visual loss was not fully investigated and the heart was not examined at autopsy though he had a longstanding heart murmur. Neuropathological studies showed pancerebellar cortical atrophy, cell loss in the inferior olivary nuclei and old right middle cerebral artery infarctions in both brothers. Biochemical assays for known metabolic diseases were negative. We suggest that this syndrome represents a unique autosomal recessive form of progressive myoclonus epilepsy of unclear aetiology. It is distinguished from other familial myoclonus epilepsies by the presence of early onset cerebellar ataxia, supranuclear ophthalmoplegia, pigmentary retinopathy and possibly cardiac valvulopathy with subsequent cerebral emboli.

Adult↗
PubMed1984

Development of encephalopathic features similar to Reye syndrome in rabbits.

The progression of neurological abnormalities through four or five clinically distinguishable levels of deepening coma and the development of a fatty liver are the hallmarks of Reye syndrome. A number of animal models have been described that result in fatty liver formation with minimal, static, or catastrophic neurological changes. In this study, we attempted to produce neurological features in rabbits that reflected a rostral-caudal progression of abnormalities that could be categorized into clinically distinguishable levels reminiscent of Reye syndrome. This was accomplished by the intracisternal administration of 0.5-25 mg of 11,14-icosadienoic acid (20:2 omega 6) suspended in a mixture of rabbit serum and isotonic saline solution. A reproducible, dose-titratable spectrum of at least four levels of deepening coma could be produced at will. Increases in serum glutamate-oxaloacetate transaminase and creatine kinase and changes in serum glucose resulted 1-2 hr after the neurological abnormalities were evoked. Other unsaturated fatty acids produced similar responses. Those tested included 18:1 omega 9, 18:2 omega 6, 18:3 omega 3, 20:3 omega 6, 20:4 omega 6, and 22:4 omega 6 fatty acids. Saturated fatty acids, including 6:0, 8:0, 16:0, 18:0, and 20:0, failed to elicit these effects. The abnormalities were sustained for 30-120 min after a single dose. Full recovery was observed in some animals that had not reached the fourth level of our grading system for coma. Pretreatment of the rabbits with aspirin modulated the neurological abnormalities. Twenty micrograms of bee venom melittin, which activates endogenous phospholipase A2, administered intracisternally into rabbits also produced signs of level 3 (our grading system) coma for several hours. These findings suggest a possible role for polyunsaturated fatty acids in the development of Reye syndrome and offer a means of producing the neurological components of that syndrome in a laboratory animal.

Acetaminophen↗
PubMed1983

Herpes simplex virus encephalitis. Diagnostic and treatment considerations.

The patient with meningoencephalitis should be evaluated carefully for the presence of focal signs referable to involvement of the frontotemporal regions of the brain. A significant percentage of cases of encephalitis with discrete focal features are caused by infection with herpes simplex virus. If focal signs are not present, the patient should be managed conservatively but examined regularly because focal neurologic dysfunction may present at any time in the course of disease. If there is clinical and electrographic evidence of involvement of the frontotemporal lobes, radiographic imaging is indicated as well as studies of the serum and cerebrospinal fluid for antibodies indicative of a recent infection with herpes simplex virus. Assuming that the radiographic scans identify the characteristic changes of a focal encephalitis and that the antibody responses are indicative of a recent herpes simplex virus infection, brain biopsy should be done in order to confirm the diagnosis. With positive evidence for HSE, treatment with ara-A should be initiated and continued for 10 days. If the biopsy proves negative for virus, ara-A should be discontinued and the patient managed conservatively (Fig. 3). Although the NIAID study of ara-A treatment of HSE is encouraging, the numbers are small and the evidence is, at best, only suggestive. It is reasonable to use this drug until a better one becomes available for the treatment of known HSE, and treatment should be instituted early before cellular injury is extensive. In centers familiar with this problem, biopsy confirmation of the diagnosis is a simple and informative procedure and can be defended. If patients cannot be moved to a center of this type, physicians familiar with the many facets of this problem should be consulted, and a decision regarding biopsy and treatment should be individualized in light of the circumstances. Biopsy should only be undertaken when the procedure can be done with minimal risk to the patient and the assurance that the maximum amount of information can be gained.

Acyclovir↗
PubMed1977

Persistent and fatal central-nervous-system ECHOvirus infections in patients with agammaglobulinemia.

We observed persistent ECHOvirus infection of the central nervous system, as defined by continued presence of isolatable virus in cerebrospinal fluid, in five patients with agammaglobulinemia. The immunologic deficit in each was characterized by absence of surface-immunoglobulin-bearing B lymphocytes and of lymph-node cortical follicles, but normal T-cell function. ECHOviruses 30, 19, 9 and 33 were recovered from cerebrospinal fluid for periods varying from two months to three years. The patients had few signs of acute central-nervous-system infection. Three of the five patients had a dermatomyositis-like syndrome, with peripheral lymphocytes that reacted with anti-human leukemia-specific primate and rabbit serums in a cytotoxicity assay. These data suggest that intact B-cell function is essential for eradication of ECHOvirus infection of the central nervous system.

Adult↗
PubMed1977

Perceptuo-motor dysfunction in the child with hemiplegia.

Eighteen children with hemiplegia were examined by means of standard neurological and other, specialized, sub-tests to define the extent of their perceptuo-motor dysfunction. Particular attention was paid to auditory language function, praxis, visuo-spatial skills, body schema, tactile defensiveness and inattention. The side of the hemiplegia was not found to predispose to any specific dysfunction, with the exception of inattention which was seen only in those with left-sided hemiplegia. Children with a history of familial sinistrality had a higher incidence of speech problems, particularly in the area of auditory language and speech delay. The results are discussed in the light of therories of plasticity and cerebral organization.

Adolescent↗
PubMed1976

Inclusion bodies in brain cell cultures from Creutzfeldt-Jakob disease.

Brain cell cultures were established from 20 patients with various forms of dementia and studied for evidence of virus induced alterations. Changes were detected in the cultured cells from 1 patient (L.C.) with the clinical and pathological diagnosis of Creutzfeldt-Jakob disease. These changes were present in the early passages of the brain tissue and were not seen in the cultures from the other cases.

Cell Nucleus↗
PubMed1976

Experimental encephalitis caused by herpes simplex virus: comparison of treatment with tilorone hydrochloride and phosphonoacetic acid.

A mouse model of encephalitis caused by herpes simplex virus was used to compare the antiviral activity of tilorone hydrochloride with that of phosphonoacetic acid. These compounds were also administered simultaneously to determine whether the combination had a synergistic effect. Rates of survival and concentrations of virus in brain were used as criteria for judging the effectiveness of treatment. The fatal course of encephalitis was not altered by any treatment protocols in which tilorone hydrochloride was used alone. Four days of treatment with phosphonoacetic acid resulted in a long-term survival rate of about 15% of the infected, treated animals, and extension of this therapy for an additional three days resulted in an overall survival rate of about 35%. No increase in survival rate was obtained by use of phosphonoacetic acid and tilorone hydrochloride in combination. The concentration of virus in the brains of tilorone hydrochloride treated animals did not differ significantly from that in the untreated, infected control animals. Treatment with phosphonoacetic acid resulted in a reduction in titer of virus in brain and in an increased rate of survival.

Acetates↗
PubMed1975

Experimental herpes simplex virus encephalitis: Comparative effects of treatment with cytosine arabinoside and adenine arabinoside.

Experimental herpesvirus encephalitis in weanling mice was treated with either cytosine arabinoside or adenine arabinoside to determine the comparative effectiveness of the two compounds on survival and on the concentration of virus in the brain. The uniformly fatal course of the encephalitis was not altered by any dosage of cytosine arabinoside. In contrast, treatment with adenine arabinoside resulted in long-term survival of the majority of the infected animals. The concentration of virus measured in the brains of animals treated with two different dosages of cytosine arabinoside indicated initial suppression of viral replication with a subsequent rise to levels higher than those in the untreated controls. In the brains of adenine arabinoside-treated animals, titers of virus gradually diminished to undetectable levels by the eighth day after institution of therapy.

Animals↗