Fang tip spread, puncture distance, and suction for snake bite.

We measured the distance between fang tip punctures in defensive bites by western diamondback rattlesnakes (Crotalus atrox) and the distance between their retracted fangs. Because the fang tips at penetration average 112% further apart than their bases at rest, The Extractor, a device widely marketed in the United States for snake bite first aid, will not simultaneously cover both punctures of most adult New World pitvipers.

Spectral editing technique for the in vitro and in vivo detection of taurine.

In vivo 1H NMR spectroscopy has proven to be a useful noninvasive tool for the investigation of numerous metabolic and physiological states. Taurine is potentially a useful indicator in neonate development and is involved in a number of physiological processes. However, it could not previously be observed in the in vivo 1H spectrum because of overlap with adjacent resonances. We have developed a spectral editing technique based upon double quantum filtration which allows the taurine resonances to be resolved from adjacent peaks. The experiment is demonstrated both on perchloric acid rodent brain extract and on rodent brain homogenate.

Direct thyroid hormone signalling via ADP-ribosylation controls mitochondrial nucleotide transport and membrane leakiness by changing the conformation of the adenine nucleotide transporter.

Addition of triiodothyronine at 10 pM in vitro to hypothyroid rat liver mitochondria doubles the rate of the adenine nucleotide transporter at low ADP concentrations. Nicotinamide abolishes this effect in parallel with its inhibition of the ADP-ribosylation of an inner membrane protein identical in size to the transporter. Nicotinamide also renders euthyroid preparations indistinguishable from hypothyroid ones. A mechanism is offered to explain these findings in which it is proposed that the adenine nucleotide transporter is a true allosteric protein and that its covalent modification by ADP-ribosylation increases the stability of the less favoured externally-facing C-conformation and thus increases the proportion of transporters in this orientation: although the C-conformation is significantly more leaky to cations than the tight matrix-facing M-conformation, this enhances ADP import. This model is shown to offer an explanation not only for the transport effects of T3 but also for those of oxidative stress and ADP-ribosylation inhibitors on Ca2+, H+ and K+ transfer across the mitochondrial inner membrane. Ca2+ at 30 nM appears to stabilize the M-conformation of the transporter by a mechanism other than ADP-ribosylation.

Self-report of oral health services provided by nurses'aides in nursing homes.

PURPOSE: The purpose of this investigation was to identify the oral healthcare role of nurses' aides in nursing homes. Nurses' aides were asked to report what preventive and referral oral health services they provided, factors that encourage and discourage performance of these services, and their perceived knowledge of oral hygiene care procedures. METHODS: A random sample of 40% (n = 14) of nursing home facilities in southeastern Virginia was selected. A 14-item questionnaire was administered to 121 nurses' aides employed at 11 of these nursing home facilities during April, May, and June of 1991. Frequency and percentages were analyzed for discrete, nominally, and ordinally scaled data. RESULTS: Eleven of the 14 nursing homes selected agreed to participate, representing 32% of the nursing homes in the southeastern region of Virginia. Ninety-eight out of 121 questionnaires were completed and analyzed. Nurses' aides in nursing home facilities typically reported providing preventive oral health services such as mouthrinsing (71%), toothbrushing (63%), and denture cleaning procedures (37%) for nursing home residents. The majority of nurses' aides indicated that patient cooperativeness was a major factor that encouraged (71%) or discouraged (88%) the performance of oral health services. Aides typically reported suspicious and abnormal findings detected in residents' mouths to the nurse in charge of the shift (97 5). The majority of nurses' aides rated their knowledge of mouthrinses for residents with teeth (99%), denture cleaning (99%), toothbrushing (97%), fluoride mouthrinses for residences with teeth (90%), mouth checks for residents with teeth (91%), and flossing (61%) as adequate or excellent. However, a large percentage of nurses' aides rated their knowledge of saliva substitutes (45%) and flossing (39%) as poor. CONCLUSION: This study indicated that nurses' aides generally provide daily oral hygiene services to nursing home residents. Thus, the role of the dental hygienist should be to outline specific educational and curricular guidelines and conduct training programs for nurses' aides and to develop instructional materials to be used in nursing homes. Future dental hygiene graduates must be prepared to meet the needs of oral hygiene education for nurses' aides.

The rapid response of isolated mitochondrial particles to 0.1 nM-tri-iodothyronine correlates with the ADP-ribosylation of a single inner-membrane protein.

Under defined conditions liver mitochondria from hypothyroid rats show an apparent lowering of the ADP/O ratio, which can be corrected by addition in vitro of 0.1 nM-tri-iodothyronine (T3). Nicotinamide prevents this restoration by hormone, lowers the ADP/O ratio of euthyroid-rat mitochondria to hypothyroid-rat values and induces T3-sensitivity in euthyroid-rat mitoplasts indistinguishable from that found with hypothyroid-rat preparations. Incorporation into the trichloroacetic-acid insoluble fraction of mitoplasts and hypothyroid-rat mitochondria of radiolabel from [adenine-14C]-NAD+ was stimulated by T3: this stimulation was abolished by nicotinamide. The findings strongly suggest that this incorporation occurs external to the matrix. Confirming the work of others, PAGE of radiolabelled mitoplasts shows alkali-labile modification of a major species of approx. 30 kDa: both nicotinamide and T3 abolish this modification. By contrast, T3 promotes incorporation of label into a single major 11 kDa species: this incorporated label is somewhat acid-labile, and the incorporation is abolished by nicotinamide. Comparative electrophoresis of purified sub-mitoplast fractions show that the 11 kDa species is in the inner membrane and absent from the matrix. The findings are consistent with a receptor-mediated ADP-ribosylation mechanism for the rapid action of T3 on mitochondria.

The characterization of a new enzyme from rat liver mitochondria, oligophosphoglyceroyl-ATP 3'-phosphodiesterase.

By using an assay based on the precipitation of intact 14C-labelled substrate, an activity has been located in the mitochondrial fraction of rat liver which selectively hydrolyses the 3' ester link in the fairly recently discovered oligomeric tetraphosphate derivative of ATP and glyceric acid for which the structure 3-phospho[glyceroyl-gamma-triphospho-5'-adenosine-3'-3-phospho]n-glyceroyl- gamma-triphospho-5'-adenosine has been proposed [Hutchinson, Morris & Mowbray (1986) Biochem. J. 234, 623-627]. This enzyme activity (Mr 85,000) has been purified approx. 30-fold from washed mitochondria by (NH4)2SO4 precipitation and f.p.l.c. The apparent Km for substrate (adenosine equivalents) is around 35 microM. The recovery of total activity is about 20%, and this, allied to the relatively low Vmax. found in contrast with the rapid turnover of oligomer seen in post-ischaemic tissues, suggests that some activating factors have been lost in purification. Percoll-gradient studies confirm that the activity is mitochondrial and not lysosomal or endoplasmic-reticular. The activity is latent in intact mitochondria; it is not, however, associated with intact inner-membrane vesicles but released during their preparation, implying an intermembrane-space location. The product of the enzyme is proposed to be the monomeric unit 3-phosphoglyceroyl-gamma-triphospho-5'-adenosine, from which digestion with snake-venom phosphodiesterase releases ADP.

Fatal rattlesnake envenomation in Arizona: 1969-1984.

Case histories of the last nine fatalities (1969-1984), in which the cause of death on the State of Arizona Certificate of Death was snakebite, were reviewed. Six males and three females ranged in age from 2 to 77 years, and were bitten between 0800-2100 hours from April to September. Bites in three adult males were "illegitimate" and of these, two were by captive Mojave rattlesnakes, Crotalus s. scutulatus. The latter two victims had been bitten previously and remained at home, refusing treatment. In the other seven victims, the snakes involved were not identified. However, all localities where bites occurred were within the geographical and altitudinal range for Crotalus atrox and C. s. scutulatus. The apparent cause of death was prolonged hypotension with major organ system failure in five, intestinal hemorrhage in one, and was unknown in three. Major organs were involved as follows: cardiac failure (two); noncardiac pulmonary edema (two); renal failure (two); unconsciousness with airway obstruction and brain damage (two); and coagulopathy with multiple hemorrhage sites (one). Seven of the nine deaths appeared to be preventable. Four delayed going to a medical facility and six did not have hypotension corrected. Antivenin was not administered early (first four hours) or in adequate amounts (10 vials or more) because of delayed arrival in five or physician's decision in four. Pre-existing cardiac disease contributed to death of two victims. Rattlesnake bite victims should not delay travel to a medical facility and hypotension must be treated aggressively and appropriately.

Geographical variation in Crotalus scutulatus scutulatus (Mojave rattlesnake) venom properties.

Individual venom samples were analyzed from 12 specimens of Crotalus scutulatus scutulatus, from north of Tucson to the extreme southeastern region of Arizona. Six of the specimens, from north of Tucson, produced venom lethal toxicity (i.p. LD50) values in mice of 2.0-6.0 mg/kg. These coincided with the values previously reported for C. s. scutulatus in the Phoenix, Arizona, region and designated as type B venom (Glenn and Straight, 1978). In contrast, the venom LD50 of six individuals from extreme southeastern Arizona, including one individual near Tucson, ranged from 0.22-0.46 mg/kg. This corresponds to the values for C. s. scutulatus venom previously reported and designated as type A venom (Glenn and Straight, 1978). Specimens with type A venom have been collected in California, Nevada, Utah and regions of Arizona. In addition to differences in lethal toxicity, the type B venom consistently exhibits a different protein profile, greater proteolytic activity, greater hemorrhagic activity and contains little or none of the major lethal toxin, Mojave toxin, compared to the type A venom. No external morphological characteristic could be found differentiating the type A venom specimens from the type B venom specimens. These findings further confirm the geographical variation of C. s. scutulatus venom in Arizona.

Envenomation by the Mojave rattlesnake (Crotalus scutulatus scutulatus) in southern Arizona, U.S.A.

Fifteen cases of envenomation by the Mojave rattlesnake (Crotalus scutulatus scutulatus) are reviewed. Systemic effects were observed in eight patients, consisting of early hypotension (3), decreased plasma fibrinogen (3) and platelets (2), elevated fibrinolytic split products (3) and eyelid ptosis (1). Local venom effects were most common and included swelling (15), ecchymosis (10), bleb formation (6) and necrosis (3). Effects upon neuromuscular transmission were neither common nor a clinical problem. Treatment consisted of i.v. crystalloid solution (15) and antivenin (12).

Envenomation by the northern blacktail rattlesnake (Crotalus molossus molossus): report of two cases and the in vitro effects of the venom on fibrinolysis and platelet aggregation.

In two cases of human envenomation by the northern blacktail rattlesnake (Crotalus molossus molossus) there was marked swelling and ecchymosis of the bitten extremity and thrombocytopenia and, in one case, hypofibrinogenemia. Treatment consisted of i.v. antivenin, crystalloid solution, fresh frozen plasma and cryoprecipitates, with recovery in each case. In vitro studies showed that the venom had fibrinolytic and platelet aggregating properties; a coagulant effect, although present, was much less marked.

Envenomation by the Mexican lance-headed rattlesnake Crotalus polystictus: a case report.

A case of envenomation by the Mexican lance-headed rattlesnake, Crotalus polystictus, resulted in local swelling and muscle fasciculation, which abated after i.v. antivenin and an area of necrosis healed. A mild thrombocytopenia and hypofibrinogenemia with elevation of fibrin split products was noted.