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Biomedical subjects

M L Goff

Publications and source records attributed to M L Goff.

At least 37 records · Page 2Linked to original sources

New genus and six new species of chiggers (Acari: Trombiculidae and Leeuwenhoekiidae) collected from small mammals in Argentina.

Argentinacarus. n. gen., is proposed with Argentinacarus expansus, n. sp., off Irenomys tarsalis and Akodon longipilis, as type species. Quadraseta akodonica, off Akodon longipilis and Auliscomys micropus, Colicus sinpretarsus, off Histiotus montanus, Parasecia argentinensis off Phyllotis xanthopygus, Parasecia neuquenensis, off Akodon longipilis, and Andalgalomacarus xanthopyga, off Phyllois xanthopygus and Eligmodontia morgani, are described as new. All specimens were collected in Argentina.

Animals↗

Preliminary observations of the effects of phencyclidine in decomposing tissues on the development of Parasarcophaga ruficornis (Diptera: Sarcophagidae).

Larvae of Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae) were reared on tissues from rabbits administered different dosages of phencyclidine to study the effects of this drug on the development of this insect species. The rabbits were given 3.66, 7.31, and 14.62 mg of phencyclidine via ear vein infusion. No significant differences in larval growth rate were observed among the colonies, although the duration of the non-feeding portion of the third instar was shorter for larvae fed on tissues containing the drug. Mortality during the larval stage was directly related to the dosage of phencyclidine administered, ranging from 0 in the control colony to 29.0% in the colony fed on tissues from the rabbit receiving 14.62 mg of phencyclidine. Durations of the puparial stage were longer for colonies fed on tissues containing the drug. Presence of phencyclidine was detected in larvae from all colonies fed on tissues from rabbits receiving the phencyclidine using GC/MS.

Animals↗

The black soldier fly Hermetia illucens (Diptera: Stratiomyidae) as a potential measure of human postmortem interval: observations and case histories.

The black soldier fly, Hermetia illucens (L.), has been shown to be a ubiquitous inhabitant of both surface and buried human remains throughout the southern, central and western United States and Hawaii. Unlike most other species of forensically important Diptera, this species frequently dominates bodies in the dry/post decay stage of decomposition. Adults of the black soldier fly appear to initiate oviposition (egg laying) 20 to 30 days postmortem. Even at warm temperatures (27.8 degrees C), subsequent completion of the life cycle can require an additional 55 days. Life history data for H. illucens, when used in combination with data for other cohabiting arthropod species and viewed in the context of local environmental conditions, can provide medicolegal investigators with valuable parameters for estimating the postmortem intervals for badly decomposed remains.

Animals↗

Entomotoxicology. A new area for forensic investigation.

Insects and other arthropods can be valuable tools in death investigations. In addition to their use in the estimation of postmortem intervals, insects may serve as reliable alternate specimens for toxicological analyses in the absence of tissues and fluids normally taken for such purposes. Recent research has also demonstrated that the presence of drugs and/or toxins in decomposing tissues may alter the rate and patterns of development in arthropods using such tissues as food, thus potentially altering estimates of the postmortem interval. Current advances in the use of arthropods as alternate toxicological specimens and the effects of various drugs and toxins on arthropod development are reviewed here.

Animals↗

Preliminary observations of the effects of amitriptyline in decomposing tissues on the development of Parasarcophaga ruficornis (Diptera: Sarcophagidae) and implications of this effect to estimation of postmortem interval.

Larvae of Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae) were reared on tissues from rabbits administered different dosages of amitriptyline to study the effects of this drug on the development of this insect species. The rabbits were given 300, 600, and 1000 mg of amitriptyline via ear vein infusion. No significant differences in rates of larval growth were observed among the colonies. Durations of the larval stage were significantly longer for larvae fed on tissues from rabbits receiving amitriptyline. Larval mortality was observed to be 5.5% for the control colony, but ranged from 40.5 to 57.5% for the test colonies. Durations of the puparial stage were significantly longer for the colonies fed on tissues from the rabbits receiving the 600 and 1000 mg dosages of amitriptyline than for the control and colony fed on tissues from the rabbit receiving the 300 mg dosage. Observed differences in the durations of the larval and pupal stages from the test colonies were sufficient to alter a postmortem interval estimate by up to 77 h, if based on normal developmental patterns for this species at 26 degrees C. Presence of amitriptyline and nortriptyline could be detected in larvae from all colonies fed on tissues from the rabbits receiving amitriptyline using high-performance liquid chromatography (HPLC).

Amitriptyline↗

A BASIC algorithm for calculating the postmortem interval from arthropod successional data.

A computer algorithm, implemented in the BASIC language, is presented for calculating the postmortem interval (PMI) from arthropod successional data. Entomology-assisted determination of the PMI promises to be a reliable technique in cases of homicide, suicide, accidental death, and unattended death due to natural causes. The program requires, as input, the identity of arthropod taxa recovered from human remains in a death scene investigation and machine-readable data on carrion-associated arthropod taxa and their known successional patterns of activity for the same geographical area. The program performs rapid comparisons of these lists and, on output, calculates an upper and lower estimate of the PMI, identifies the definitive taxa for these limits, and determines if the remaining corpse taxa have known successional patterns that are consistent for this estimate. An alternate output is provided if one or more corpse taxa do not overlap all the others at any single time in the succession. In that event, the user is prompted to recheck the identity of the non-overlapping taxon or taxa or reevaluate the environmental circumstances surrounding the case in question. Results of the analysis are saved to an ASCII file for output to a printer for making paper copies useful for the entomologist's Case Study Final Report. This program may make possible wider use of this technique in law enforcement and medical investigator offices that utilize both forensic entomologist expertise and IBM PCs (or compatible computers).

Accidents↗

Preliminary observations of the effect of methamphetamine in decomposing tissues on the development rate of Parasarcophaga ruficornis (Diptera: Sarcophagidae) and implications of this effect on the estimations of postmortem intervals.

Larvae of Parasarcophaga ruficornis (Fabricius) (Diptera: Sarcophagidae) were reared on tissues from rabbits administered different dosages of methamphetamine to study the effects of this drug on development of this species. The rabbits were given 37.5, 71.4, and 142.9 mg of methamphetamine via ear vein infusion. From Hours 30 to 60, larvae feeding on tissues from rabbits receiving 71.4 and 142.9 mg of methamphetamine developed more rapidly than larvae from the control colony and those feeding on tissues from the rabbit receiving 37.5 mg of methamphetamine. The time required for pupariation was significantly greater for colonies fed on tissues from methamphetamine-dosed rabbits than for the control. These differences were sufficient to alter postmortem interval estimates based on larval development by up to 18 h and estimates based on puparial development by up to 48 h. The presence of methamphetamine or amphetamine could not be detected in Diptera larvae in this experiment using radioimmunoassay techniques, as there was a nonspecific reaction, resulting in a false positive.

Amphetamine↗

Effect of carcass size on rate of decomposition and arthropod succession patterns.

Decomposition studies were conducted using two carcasses of domestic pigs, Sus scrofa L., 8.4 kg and 15.1 kg in weight, to determine the effects of carcass size on the rate of decomposition, composition of the arthropod fauna, and succession patterns. A total of 46 arthropod taxa were recovered during this study. No size-related differences were observed between carcasses with respect to composition of the arthropod fauna or patterns of succession. A greater number of arthropods were observed attracted to the 15.1-kg carcass, and the rate of decomposition observed was more rapid for the 15.1-kg carcass than for the 8.4-kg carcass. Internal temperatures of the 8.4-kg carcass were more directly related to external ambient temperatures during the fresh and bloated stages of decomposition. During the decay stage, both carcasses generated internal temperatures significantly above ambient temperatures. Following this stage, internal temperatures fell to approximate ambient temperatures during the postdecay and remains stages.

Animals↗

Presence of fecal material in diapers as a potential source of error in estimations of postmortem interval using arthropod development rates.

Second instar larvae of the fly Chrysomya megacephala (Diptera, Calliphoridae) were recovered from the diapers of a 16-month-old child abandoned by her mother on Oahu, Hawaii. The development of these larvae indicated a minimum period of 23.5 h of exposure prior to discovery of the child. Larvae of this species of fly are not normally associated with living tissues in Hawaii, but rather with feces and remains during the early stages of decomposition. Had the child in this case died and data not been provided detailing the site of infestation, the postmortem interval estimated would have been significantly longer than was actually the case, because of the development of the larvae inside the diapers of the living child. The need for caution in cases involving deaths of infants, the elderly, and individuals not capable of caring for themselves is stressed.

Animals↗

Comparison of insect species associated with decomposing remains recovered inside dwellings and outdoors on the island of Oahu, Hawaii.

A comparison of insects collected from 35 cases of decomposing remains on the island of Oahu, Hawaiian Islands (14 from indoor situations and 21 from outdoors), yielded a total of 22 species of insects in 3 orders and 12 families. Of these, five species were recovered in both indoor and outdoor situations. Remains recovered indoors had a greater variety of Diptera larvae associated with them, while remains discovered outdoors had a greater variety of Coleoptera species present. Some species of insects were restricted to remains discovered indoors, while others were found only associated with remains in outdoor situations. Knowledge of the species of insects associated with different habitats may serve to provide information concerning the history of the remains.

Animals↗

Effect of heroin in decomposing tissues on the development rate of Boettcherisca peregrina (Diptera, Sarcophagidae) and implications of this effect on estimation of postmortem intervals using arthropod development patterns.

Larvae of the flesh fly Boettcherisca peregrina (Robineau-Desvoidy) were reared on the tissues of rabbits to study the effects of heroin on the development rates of this species. The rabbits were given 6, 12, 18, and 24 mg of heroin by cardiac puncture. From Hours 18 to 96, larvae feeding on tissues containing heroin (as morphine) developed more rapidly than those feeding on tissues from the control. The time required for pupation was significantly greater for colonies fed on tissues from heroin-dosed rabbits than for the control colony. The differences observed in the rates of development were sufficient to alter postmortem interval estimates based on larval development by up to 29 h and estimates based on pupal development by 18 to 38 h.

Animals↗

Determination of postmortem interval by arthropod succession: a case study from the Hawaiian Islands.

A postmortem interval of 34 to 36 days was established for remains recovered on the island of Oahu, Hawaii, based on interpretations of patterns of arthropod succession on the remains. This interval was primarily based on the presence of adult specimens of Philonthus longicornis (family Staphylinidae), mature larvae of Piophila casei (family Piophilidae), and empty puparial cases of Chrysomya rufifacies (family Calliphoridae). Species and developmental stages of two additional Coleoptera species and three additional Diptera species were also present, which was consistent with the estimated interval, although not definitive.

Adult↗

Effects of larval population density on rates of development and interactions between two species of Chrysomya (Diptera: Calliphoridae) in laboratory culture.

Rearing of Chrysomya megacephala (F.) and Chrysomya rufifacies (Macquart) in pure cultures at seven different population densities (larvae per gram of liver) demonstrated an inverse relationship between density and the duration of the larval stage. In pure cultures, larval mortality rates decreased with increasing density until an optimum density was reached (8 larvae/g liver for C. megacephala and 10 larvae/g liver for C. rufifacies), then decreased directly with density. Puparial and adult weights varied inversely with density for both species in pure cultures. Internal feeding mass temperatures were above ambient temperatures for all cultures, with maximum temperatures recorded in cultures with 20 and 40 larvae/g liver for G. rufifacies and C. megacephala, respectively. In paired encounters, larvae of C. rufifacies were cannibalistic and predatory on C. megacephala larvae after the first instar. In mixed cultures of these two species, the larval mortality of C. rufifacies remained relatively stable, whereas the larval mortality of C. megacephala increased directly with population density.

Analysis of Variance↗

Effect of cocaine in tissues on the development rate of Boettcherisca peregrina (Diptera: Sarcophagidae).

Larvae of the flesh fly, Boettcherisca peregrina (Robineau-Desvoidy), were reared on the tissue of rabbits to study the effects of cocaine and benzoylecognine on development rates. The rabbits were given 35, 69, and 137 mg of cocaine through cardiac puncture. From hours 30 to 70, larvae developed more rapidly on tissue containing cocaine, benzoylecognine, or both, from rabbits injected with 69 and 137 mg of cocaine than on tissue from rabbits injected with 35 mg of cocaine or no cocaine. Total development times required for pupation and adult eclosion were shortened correspondingly. Differences observed in the rate of development were sufficient to alter postmortem interval estimates based on larval development in decomposing human tissues by up to 24 h.

Animals↗

Two new species of schoengastiine chiggers (Acari: Trombiculidae) from Brazil and rediagnosis of Arisocerus Brennan, 1970.

Colicus spinosus Goff & Gettinger, n. sp., is described from Marmosa agilis. Quadraseta brasiliensis Goff & Gettinger, n. sp., is described from Marmosa agilis, Monodelphis americana, and Oryzomys capito. All specimens were collected in central Brazil. The diagnosis of the genus Arisocerus Brennan, 1970, is corrected to describe the setation of the palpal tarsus as 7BS rather than 6BS as listed in the original description.

Animals↗