Analysis of candidate genes for morphine preference quantitative trait locus Mop2

Compared to DBA/2J (D2), C57BL/6J (B6) inbred mice exhibit strong morphine preference when tested using a two-bottle choice drinking paradigm. A morphine preference quantitative trait locus (QTL), Mop2, was originally mapped to proximal chromosome (Chr) 10 using a B6xD2 F2 intercross population, confirmed with reciprocal congenic strains and fine mapped with recombinant congenic strains. These efforts identified a ∼ 10-Million base pair (Mbp) interval, underlying Mop2, containing 35 genes. To further reduce the interval, mice from the D2.B6-Mop2-P1 congenic strain were backcrossed to parental D2 mice and two new recombinant strains of interest were generated: D2.B6-Mop2-P1.pD.dB and D2.B6-Mop2-P1.pD.dD. Results obtained from testing these strains in the two-bottle choice drinking paradigm suggest that the gene(s) responsible for the Mop2 QTL is one or more of 22 remaining within the newly defined interval (∼ 7.6 Mbp) which includes Oprm1 and several other genes related to opioid pharmacology. Real-time qRT-PCR analysis of Oprm1 and opioid-related genes Rgs17, Ppp1r14c, Vip, and Iyd revealed both between-strain and within-strain expression differences in comparisons of saline- and morphine-treated B6 and D2 mice. Analysis of Rgs17 protein levels also revealed both between-strain and within-strain differences in comparisons of saline- and morphine-treated B6 and D2 mice. Results suggest that the Mop2 QTL represents the combined influence of multiple genetic variants on morphine preference in these two strains. Relative contributions of each variant remain to be determined.

Quantitative trait loci for electrical seizure threshold mapped in C57BLKS/J and C57BL/10SnJ mice

We mapped the quantitative trait loci (QTL) that contribute to the robust difference in maximal electroshock seizure threshold (MEST) between C57BLKS/J (BKS) and C57BL10S/J (B10S) mice. BKS, B10S, BKS × B10S F1 and BKS × B10S F2 intercross mice were tested for MEST at 8-9 weeks of age. Results of F2 testing showed that, in this cross, MEST is a continuously distributed trait determined by polygenic inheritance. Mice from the extremes of the trait distribution were genotyped using microarray technology. MEST correlated significantly with body weight and sex; however, because of the high correlation between these factors, the QTL mapping was conditioned on sex alone. A sequential series of statistical analyses was used to map QTLs including single-point, multipoint and multilocus methods. Two QTLs reached genome-wide levels of significance based upon an empirically determined permutation threshold: chromosome 6 (LOD = 6.0 at ∼69 cM) and chromosome 8 (LOD = 5.7 at ∼27 cM). Two additional QTLs were retained in a multilocus regression model: chromosome 3 (LOD = 2.1 at ∼68 cM) and chromosome 5 (LOD = 2.7 at ∼73 cM). Together the four QTLs explain one third of the total phenotypic variance in the mapping population. Lack of overlap between the major MEST QTLs mapped here in BKS and B10S mice and those mapped previously in C57BL/6J and DBA/2J mice (strains that are closely related to BKS and B10S) suggest that BKS and B10S represent a new polygenic mouse model for investigating susceptibility to seizures.

Racemization of Amino Acids in Dipeptides Shows COOH > NH2 for Non-Sterically Hindered Residues

The relative rates of racemization for amino acid residues at the NH(2) and COOH ends of 37 different dipeptides were determined. In nine dipeptides containing alanine, leucine, phenylalanine, aspartic acid, and methionine, the amino acid residue racemized faster at the COOH-terminal position than at the NH(2)-terminal position (COOH > NH(2)). The sterically hindered amino acids isoleucine and valine showed NH(2) > COOH. Six proline dipeptides showed NH(2) > COOH. Intramolecular effects have been invoked to explain these surprising results.

Confirmation of multiple seizure susceptibility QTLs on chromosome 15 in C57BL/6J and DBA/2J inbred mice

To confirm seizure susceptibility (SZS) quantitative trait loci (QTLs) on chromosome (chr) 15 identified previously using C57BL/6J (B6) and DBA/2J (D2) mice and to refine their genomic map position, we studied a set of three congenic strains in which overlapping segments of chr 15 from D2 were transferred onto the B6 background. We measured thresholds for generalized electroshock seizure (GEST) and maximal electroshock seizure (MEST) in congenic strains and B6-like littermates and also tested their responses to kainic acid (KA) and pentylenetetrazol (PTZ). Results document that MEST is significantly lower in strains 15M and 15D, which harbor medial and distal (telomeric) segments of chr 15 (respectively) from D2, compared with strain 15P, which harbors the proximal (acromeric) segment of chr 15 from D2, and with control littermates. Congenic strains 15P and 15M exhibited greater KA SZS compared with strain 15D and B6-like controls. All congenic strains were similar to controls with regard to PTZ SZS. Taken together, results suggest there are multiple SZS QTLs on chr 15 and that two QTLs harbor gene variants that affect MEST and KA SZS independently. The MEST QTL is refined to a 19 Mb region flanked by rs13482630 and D15Mit159. This interval contains 350 genes, 183 of which reside in areas where the polymorphism rate between B6 and D2 is high. The KA QTL interval spans a 65 Mb region flanked by markers D15Mit13 and rs31271969. It harbors 83 genes in highly polymorphic areas, 310 genes in all. Complete dissection of these loci will lead to identification of genetic variants that influence SZS in mice and provide a better understanding of seizure biology.

Dementia in a retired world boxing champion: case report and literature review

OBJECTIVE

Dementia in retired boxers, also referred to as "dementia pugilistica" (DP), is usually attributed to repeated concussive and subconcussive blows to the head. We report the case of a former world boxing champion whose progressive cognitive decline could be ascribed to DP, cerebral infarcts and Wernicke-Korsakoff syndrome. This case demonstrates that dementia in retired boxers may be caused and/or exacerbated by etiologic factors other than DP.

MATERIALS AND METHODS

We correlated the clinical features with the histochemical and immunohistochemical changes observed on autopsy brain material from a retired boxer, reviewed the literature on boxing-related dementia, and compared our findings with previous reports on DP.

RESULTS

Neuropathologic examination revealed numerous neurofibrillary tangles (NFTs), rare neuritic plaques (NPs), multiple cerebral infarcts, fenestrated septum pellucidum, atrophic and gliotic mamillary bodies, and pale substantia nigra and locus ceruleus.

CONCLUSIONS

Our neuropathologic data confirmed the notion that dementia in retired boxers could be due to several factors such as DP, multiple cerebral infarcts and Wernicke-Korsakoff syndrome. Our findings illustrate the need to comprehensively examine former boxers with dementia as well as carefully evaluate the neuropathologic changes that may cause or contribute to the patient's cognitive and behavioral symptoms. Such an approach is crucial in order to provide prompt and more definitive therapies.

Quantitative genetic study of maximal electroshock seizure threshold in mice: evidence for a major seizure susceptibility locus on distal chromosome 1

We conducted a quantitative trait locus (QTL) mapping study to dissect the multifactorial nature of maximal electroshock seizure threshold (MEST) in C57BL/6 (B6) and DBA/2 (D2) mice. MEST determination involved a standard paradigm in which 8- to 12-week-old mice received one shock per day with a daily incremental increase in electrical current until a maximal seizure (tonic hindlimb extension) was induced. Mean MEST values in parental strains were separated by over five standard deviation units, with D2 mice showing lower values than B6 mice. The distribution of MEST values in B6xD2 F2 intercrossed mice spanned the entire phenotypic range defined by parental strains. Statistical mapping yielded significant evidence for QTLs on chromosomes 1, 2, 5, and 15, which together explained over 60% of the phenotypic variance in the model. The chromosome 1 QTL represents a locus of major effect, accounting for about one-third of the genetic variance. Experiments involving a congenic strain (B6.D2-Mtv7(a)/Ty) enabled more precise mapping of the chromosome 1 QTL and indicate that it lies in the genetic interval between markers D1Mit145 and D1Mit17. These results support the hypothesis that the distal portion of chromosome 1 harbors a gene(s) that has a fundamental role in regulating seizure susceptibility.

Acute cocaine-induced seizures: differential sensitivity of six inbred mouse strains

Mature male and female mice from six inbred stains were tested for susceptibility to behavioral seizures induced by a single injection of cocaine. Cocaine was injected ip over a range of doses (50-100 mg/kg) and behavior was monitored for 20 minutes. Seizure end points included latency to forelimb or hindlimb clonus, latency to clonic running seizure and latency to jumping bouncing seizure. A range of strain specific sensitivities was documented with A/J and SJL mice being most sensitive and C57BL/6J most resistant. DBA/2J, BALB/cByJ and NZW/LacJ strains exhibited intermediate sensitivity. EEG recordings were made in SJL, A/J and C57BL/6J mice revealing a close correspondence between electrical activity and behavior. Additionally, levels of cocaine determined in hippocampus and cortex were not different between sensitive and resistant strains. Additional studies of these murine strains may be useful for investigating genetic influences on cocaine-induced seizures.

Revenge of the mutant cockroach: culturally adapted storytelling in the treatment of a low-income African American boy

A clinical case is presented in which a culturally adapted storytelling technique was used in child therapy with a socioeconomically disadvantaged African American boy. In this intervention, the child and therapist co-created a story by taking turns adding to the story during therapy sessions. The child's contributions to the story were interpreted by taking into account his sociocultural context, and the therapist's responses were adapted to reflect relevant sociocultural factors. Advantages of storytelling techniques in child therapy are presented, and issues to consider when using these techniques with culturally diverse populations are discussed.

Mapping loci for pentylenetetrazol-induced seizure susceptibility in mice

DBA/2J (D2) and C57BL/6J (B6) mice exhibit differential sensitivity to seizures induced by various chemical and physical methods, with D2 mice being relatively sensitive and B6 mice relatively resistant. We conducted studies in mature D2, B6, F1, and F2 intercross mice to investigate behavioral seizure responses to pentylenetetrazol (PTZ) and to map the location of genes that influence this trait. Mice were injected with PTZ and observed for 45 min. Seizure parameters included latencies to focal clonus, generalized clonus, and maximal seizure. Latencies were used to calculate a seizure score that was used for quantitative mapping. F2 mice (n = 511) exhibited a wide range of latencies with two-thirds of the group expressing maximal seizure. Complementary statistical analyses identified loci on proximal (near D1Mit11) and distal chromosome 1 (near D1Mit17) as having the strongest and most significant effects in this model. Another locus of significant effect was detected on chromosome 5 (near D5Mit398). Suggestive evidence for additional PTZ seizure-related loci was detected on chromosomes 3, 4, and 6. Of the seizure-related loci identified in this study, those on chromosomes 1 (distal), 4, and 5 map close to loci previously identified in a similar F2 population tested with kainic acid. Results document that the complex genetic influences controlling seizure response in B6 and D2 mice are partially independent of the nature of the chemoconvulsant stimulus with a locus on distal chromosome 1 being of fundamental importance.

Genotyping microsatellite polymorphisms by agarose gel electrophoresis with ethidium bromide staining: application to quantitative trait loci analysis of seizure susceptibility in mice

Agarose gel electrophoresis with ethidium bromide staining (AGE/EBS) is an efficient and reliable method for analyzing microsatellite polymorphisms. We report the use of AGE/EBS for analyzing DNA microsatellite polymorphisms in a preliminary quantitative trait loci (QTL) study of seizure susceptibility in which a candidate gene strategy was used to direct initial mapping efforts. F2 intercross progeny, derived from seizure-sensitive DBA/2J (D2) and seizure-resistant C57BL/6J (B6) inbred strains of mice, were tested for their sensitivity to the seizure-inducing effect of pentylenetetrazol (PTZ), a gamma-aminobutyric acid (GABA) receptor antagonist. A semi-automated method is described, in which DNA microsatellites were amplified by polymerase chain reaction (PCR) to yield products of 100-200 base pair (bp) in length. Alleles were separated on 3-6% MetaPhor agarose gels, stained with ethidium bromide, and visualized by ultraviolet (UV) illumination. Univariate analysis of genotype and phenotype data provides evidence for a seizure-related QTL on chromosome 5, near genes coding for the GABAA receptor subunits alpha 5 and gamma 3. Interestingly, this suggestive QTL derives from the more resistant B6 strain, but it nonetheless provides impetus for the characterization of possible strain differences in these two candidate genes. Overall, these results demonstrate that AGE/EBS can be useful for rapid screening of genomic regions of special interest in QTL mapping studies.

Genetic influences on electrical seizure threshold

C57BL/6J (B6) and DBA/2J (D2) mice have been characterized previously as seizure-resistant and seizure-sensitive, respectively, a distinction based primarily upon a differential response to the convulsant effects of various drugs. In the present study, electroconvulsive shock (ECS) was used to assess maximal electroshock threshold (MET) in B6, D2 and hybrid mice. Results revealed that D2 mice have a significantly lower MET compared to B6 mice. There was also a significant gender effect for B6 and F2 mice with females exhibiting a lower MET compared to males. METs for F1 and F2 intercross mice were intermediate between the two parental strains. The difference in variance between F2 and F1 generation mice indicated that about three-quarters of the total variance is due to genetic influence. Taken together, results of this study suggest that the large difference in MET between B6 and D2 mice is a highly heritable trait which may yield to genetic dissection through use of quantitative trait locus mapping.

Mapping murine loci for seizure response to kainic acid

Mature DBA/2J (D2) mice are very sensitive to seizures induced by various chemical and physical stimuli, whereas C57BL/6J (B6) mice are relatively seizure resistant. We have conducted a genome-wide search for quantitative trait loci (QTLs) influencing the differential sensitivity of these strains to kainic acid (KA)-induced seizures by studying an F2 intercross population. Parental, F1, and F2 mice (8-10 weeks of age) were injected subcutaneously with 25 mg/kg of KA and observed for 3 h. Latencies to focal and generalized seizures and status epilepticus were recorded and used to calculate an overall seizure score. Results of seizure testing indicated that the difference in susceptibility to KA-induced seizures between D2 and B6 mice is a polygenic phenomenon with at least 65% of the variance due to genetic factors. First-pass genome screening (10-cM marker intervals) in F2 progeny (n = 257) documented a QTL of moderate effect on Chromosome (Chr) 1 with a peak LOD score of 5.5 (17% of genetic variance explained) localized between D1Mit30 and D1Mit16. Provisional QTLs of small effect were detected on Chr 11 (D11Mit224-D11Mit14), 15 (D15Mit6-D15Mit46) and 18 (D18Mit9-D18Mit144). Multiple locus models generally confirmed the Mapmaker/QTL results and also provided evidence for another QTL on Chr 4 (D4Mit9). Multilocus analysis of seizure severity suggested that additional loci on Chrs 5 (D5Mit11), 7 (D7Mit66), and 15 (D15Nds2) might also contribute to KA-induced seizure response. Overall, our results document a complex genetic determinism for KA-induced seizures in these mouse strains with contributions from as many as eight QTLs.

Differential susceptibility to seizures induced by systemic kainic acid treatment in mature DBA/2J and C57BL/6J mice

Mature DBA/2J (D2) and C57BL/6J (B6) mice aged 9-10 weeks were studied to determine susceptibility to behavioral seizures induced by kainic acid (KA) and the possible influence exerted by differences in metabolism and blood-brain barrier (BBB) transport. Mice were observed for 4 h after subcutaneous (s.c.) KA injection. Behavioral seizure parameters included latency to first seizure (clonus), latency to tonic/clonic seizure, and latency to status epilepticus (SE). At a KA dose of 25 mg/kg, 80% of D2 mice exhibited tonic/clonic seizures, whereas all B6 mice remained seizure-free. At 30 mg/kg, tonic/clonic seizures were observed in 100% of D2 mice and 25% of B6 mice. Of D2 mice exhibiting at least one clonic seizure in response to KA at a dose of 25 mg/kg, 50% entered SE and eventually died. Administration of [3H]KA (6.6 x 10(6) dpm) at doses of 25 mg/kg (convulsive) or 11.1 micrograms (nonconvulsive) to mice of both strains resulted in similar levels of radioactivity in cortex, hippocampus, and cerebellum 30 and 60 min after injection. Bioconversion of [3H]KA to a radiolabeled brain metabolite in vivo could not be documented in mice from either strain. Results confirm previously reported differences between D2 and B6 mice in their relative susceptibility to seizures induced by systemic KA administration and suggest that these differences are not related to strain-specific variation in metabolism or BBB transport of KA. Further studies of these two strains of mice may be useful for investigating genetic influences upon seizure susceptibility.

Rat strain and age differences in kainic acid induced seizures

This study reports comparative dose-response data for kainic acid (KA) induced seizures in juvenile (35-40 days old) and adult (70-90 days old) Wistar-Furth (WF), Fisher 344 (F344), Sprague-Dawley (SD) and Long-Evans Hooded (LEH) rats. Juvenile male WF (n = 51), F344 (n = 55), SD (n = 60), LEH (n = 50) and adult male WF (n = 48), F344 (n = 52), SD (n = 52), LEH (n = 53) rats were given KA 6, 8, 10, 12 or 14 mg/kg, sc. As previously demonstrated adult WF and F344 rats showed the greatest sensitivity and most reliable convulsant responses to kainic acid; SD and LEH rats were less sensitive and showed more variable convulsant responses. Regardless of strain, all juvenile rats exhibited greater sensitivity and less variable convulsant response to KA compared to adults. This was most evident in juvenile SD and LEH rats. Results suggest that while seizure sensitivity to KA decreases with age, genetic factors may regulate the expression of this resistance.

The Venturi Fluoride Saturator project

This study was conducted to determine whether Venturi Fluoride Saturator (VFS) systems could be used to fluoridate small community and school water supply systems with an acceptable level of maintenance. VFS systems were installed and operated at four school and six community well sites according to state and federal regulations and recommendations. School VFS systems were unable to maintain optimum fluoride residuals even with substantial maintenance. All six community well site VFS systems performed acceptably, with only a few short lapses. VFS system maintenance was labor intensive. Recurring problems were caused by lengthy equipment delivery delays, the unavailability of timely technical assistance to support the VFS system, and the inadequate quality of VFS equipment and design. Based upon these findings, further expansion of the use of VFS systems either for community or school fluoridation cannot be recommended. Additional study of and improvements in the VFS system are indicated. Three major recommendations appear appropriate: (1) extensive laboratory testing of the VFS system concept under controlled conditions should be performed to determine the functioning parameters of this equipment under different hydrodynamic conditions; (2) additional research and development of the VFS unit to improve the quality of operations and the quality control of manufacturing and assembly should be undertaken; and (3) a VFS equipment distribution network should be developed, with sufficient logistical and technical support to supply equipment parts and expertise for installation, monitoring, and maintenance in a timely and efficient manner.

Strain differences in convulsive response to the excitotoxin kainic acid

We describe a strain of rats (Wistar-Furth) that is highly susceptible to the neurotoxic effects of kainic acid (KA) and presents a reliable and quantifiable (with low within-group variability) animal model of status epilepticus. Wistar-Furth rats are more sensitive and demonstrate a less variable convulsant response than Sprague-Dawley and Long-Evans rats when tested for total time in seizure activity, latency to onset of first seizure, latency to status epilepticus, seizure severity scores, and percentage exhibiting behavioral seizures and status epilepticus. Results suggest that significant heterogeneity exists in the rodent population with regard to neuronal sensitivity to an excitotoxic amino acid and indicate that strain differences are an important consideration in studies using KA.

Extraction methods for quantitation of gentamicin residues from tissues using fluorescence polarization immunoassay

Sodium hydroxide digestion of unhomogenized kidney and skeletal muscle for 20 min at 70 degrees C was a superior method for extracting gentamicin from tissues, compared with simple homogenization, trichloroacetic acid precipitation of homogenized tissue, and sodium hydroxide digestion of homogenized tissue. Fluorescence polarization immunoassay was used to quantitate gentamicin. Sodium hydroxide digestion of unhomogenized tissue allowed for the recovery of 90.0 +/- 5.9% (means +/- SD) from renal cortex and 79.9 +/- 3.5% from skeletal muscle. The limit of sensitivity was 17.4 ng/g kidney tissue, 15.8 ng/g digested muscle, and 39.0 ng/g digested heart. The within-assay coefficient of variation (CV) at 100 ng/g kidney was 9.2%; at 500 ng/g kidney, the CV was 2.5%; and at 2000 ng/g kidney, the CV was 1.5%. The between-assay coefficient of variation was less than 7.5% for all concentrations from kidney, and the 99% confidence interval at 100 ng/g kidney was 71.7-112.4 ng gentamicin/g kidney. The within-assay coefficient of variation (CV) at 100 ng/g muscle was 15%; at 500 ng/g muscle, the CV was 2.6%; and at 2000 ng/g muscle, the CV was 2.3%. The between-assay coefficient of variation was less than 15% for all concentrations from muscle, and the 99% confidence interval at 100 ng/g muscle was 72.5-136.8 ng gentamicin/g muscle. Gentamicin-free milk could be distinguished from milk containing gentamicin concentrations of 10 ng/mL milk with 95% confidence, and from milk containing concentrations of 30 ng gentamicin/mL milk with 99% confidence. Quantitative results at or below the tolerance level can be obtained within 90 min of sample acquisition using these extraction and assay methods.

Bone scintigraphy in the evaluation of extraskeletal injuries from child abuse

Bone scintigraphy is a valuable imaging modality in the examination of the battered child. It is often used to evaluate skeletal trauma. However, bone scans may also reveal subtle and unusual scintigraphic findings that, if recognized, can lead to the diagnosis of intracranial, visceral, and soft-tissue injury. Several cases of child abuse in which bone scan findings suggested the presence of injuries other than skeletal trauma are presented.

Potentiation of kainic acid epileptogenicity and sparing from neuronal damage by an NMDA receptor antagonist

The time course and severity of the excitotoxic syndrome induced in rats by s.c. injection of 10 mg/kg kainic acid (KA) was modified by pretreatment with MK801, a non-competitive inhibitor of the NMDA receptor, at doses of 0.1, 1 and 10 mg/kg. A dose-dependent increase in the severity of the KA-induced electrographic (EEG) manifestations of epilepsy was seen after MK801. This consisted of an earlier appearance and higher number of EEG seizures, longer time spent in seizures, and an earlier onset of status epilepticus. In contrast, behavioral seizures were increased only in the 0.1 mg/kg MK801 group, but abolished by higher doses. On the contrary, wet dog shakes were progressively reduced with increasing doses of MK801. Four of the 9 animals receiving KA-only group and 3 of the 10 animals in the 1 and 10 mg MK801 groups were sacrificed 5 days after KA. The brain of the KA-only rats presented diffuse gross and microscopic evidence of hemorrhagic necrosis and neuronal damage; the MK801 rats showed only minimal neuronal loss in the CA3 hippocampal sector. This study demonstrates that neuronal damage and epileptiform activity can be dissociated. Furthermore, it confirms the protective effect of MK801 against neuronal damage caused by multiple factors. Lastly, it emphasizes the need for EEG monitoring in order to accurately assess any epileptic/antiepileptic effect.

Similar antagonistic effects of Ca N-acetylhomotaurinate on depression of motor activity and lethality induced by acetaldehyde or ethanol

Among several taurine derivatives, Ca N-acetylhomotaurinate (Ca AOTA) appears to be the most active anti-acetaldehyde and anti-alcohol agent. Studies of the antagonism of the hypomotility induced by high intravenous doses of acetaldehyde or ethanol in mice and of the lethality of high intragastric doses of acetaldehyde in rats show its superiority which appears logical after systematic studies of these derivatives and their components. The reinforcing action of the nervous activity due to N-acetylation of these sulfonic aminoacids differs according to the target. Since Ca AOTA is the most active against acetaldehyde and ethanol toxicity, this central nervous action first relies on its effects on neuromodulators, neuromediators and cations primarily involved in the mechanisms of alcohol dependence through its taurine (TA) structure, its gamma-aminobutyric acid (GABA) agonist actions, its anti-opioid receptor "naloxone-like" effects and its possible activity as a subcellular Ca carrier. Ca AOTA may also intervene through its high membrane stabilizing effect. Compared with the other compounds, it appears to be the most active both in vitro on the erythrocyte membrane of the rabbit and on the human amnion membrane and ex vivo on the alcoholic rat's erythrocyte membrane. Among several taurine derivatives similarly efficient in toxicity of both acetaldehyde and ethanol, Ca AOTA is the best. Its efficiency against the most toxic metabolite of ethanol may specifically rely on Ca and TA dependence of acetaldehyde-dehydrogenase or on an aspecific mechanism such as the role of free radical scavenger due to its taurine structure. Ca AOTA appears to be a promising drug against alcoholism because of its effects on the multiple targets involved in the mechanism of alcohol dependence. A large multicentric coordinated trial has effectively confirmed the reliability of these pharmacological speculations.

Improved sodium hydroxide digestion method without homogenization for extraction of gentamicin from renal tissue

Recovery of gentamicin from renal cortical tissue (assayed by fluorescence polarization immunoassay) was highest (P less than 0.05) when using a sodium hydroxide (NaOH) digestion procedure without homogenization (90.0 +/- 5.4%), followed by homogenization with NaOH digestion (85.8 +/- 7.7%) and homogenization with trichloroacetic acid precipitation (84.4 +/- 3.3%). Simple homogenization recovered the least gentamicin (59.0 +/- 5.2%; P less than 0.05).

Family interaction and treatment adherence after stroke

Caregivers of 60 stroke patients were assessed five months after patient discharge from a stroke care unit to determine the relationship between family function and poststroke treatment adherence. Areas of family interaction which were significantly related to ratings of treatment adherence included problem solving, communication, and affective involvement. Better functioning families were consistently high on signs of treatment adherence. Findings suggest that families with specific dysfunction may not be as capable of helping patients comply with rehabilitation efforts as families who function more effectively. Thorough family assessment to identify which areas of family interaction are most problematic in relation to adherence issues is recommended.

The use of cervical caps at the University of California, Berkeley: a survey

A survey of cap use and efficacy of women who initially purchased a cervical cap at the University of California at Berkeley Student Health Service is described. It reports the follow-up of 65 U.C. women students who purchased either Vimule or Cavity-rim cervical caps from May, 1978 through June, 1981 and raises questions about cervical cap use and efficacy. Participants were divided into two groups: regular and irregular users. Of the 33 regular users, 16 experienced unplanned pregnancy during the study. Survival probabilities were 80% at 6 months, 73% at one year and 52% after 2 years. Life table analysis of the 33 regular users indicated a 20% probability of pregnancy in the first 6 months of use, 27% by 1 year and 48% by the end of 2 years.

Comparison of bupivacaine and lidocaine for intravenous regional analgesia

In a double blind study, seven volunteers were given lidocaine 0.75 per cent and bupivacaine 0.25 per cent in two trials to compare the agents for use in intravenous regional analgesia. There was no significant difference between the two agents in the duration of analgesia after removal of the tourniquet. Bupivacaine produced fewer side effects. It also consistently produced persistent analgesia on the posterolateral aspect of the forearm.

Hepatic hemangioendotheliomas and hyperbilirubinemia

A 3-week-old infant with hyperbilirubinemia and hepatomegaly secondary to hemangioendotheliomas of the liver was presented. Review of the literature produced 18 cases of associated jaundice in 182 infants with hepatic vascular tumors, an incidence of 10%. This disorder should be considered in the differential diagnosis of the infant with hepatomegaly and jaundice, particularly in the presence of gastrointestinal complaints, cutaneous hemangiomas, congestive heart failure, or abdominal bruit. Liver scan should be done in such infants to rule out vascular tumors. Although mortality appears to be high in jaundiced infants with such tumors, currently available therapeutic modalities may be of value in treating these infants.

A critical evaluation of the application of amino acid racemization to geochronology and geothermometry

In this review we have critically evaluated the application of the diagenetic racemization of amino acids to geochronology and geothermometry. Although there has been enthusiastic support given to this new method, it is our opinion that recent developments suggest a more cautious approach. We have discussed the pitfalls and inhereent complications, while outlining the advances which have been accomplished. We conclude that this is an innovative approach which will add valuable information to the scientific literature. However, since our fundamental understanding of diagnetic racemization is still limited, many of the age and paleotemperature estimates which have been assigned to fossil specimens may be unreliable.

Continuous-flow system for determination of diffusion coefficients: use of a natural membrane

A natural membrane was employed in an automated diffusion system. A mature male Mongolian gerbil sebaceous gland pad was excised and mounted into a suitable retainer so that the external surface was oriented toward the concentrated aqueous drug solution. Aqueous solutions of benzoic acid and the three commonly used parabens were studied. The gerbil sebaceous pad effectively prevented any diffusion of these drug solutions within 15 hr. Water by itself, however, was transported through the skin even against a pressure gradient. Although no apparent diffusion of these compounds occurred, a significant amount of drug was retained by the sebaceous pad. An expression for membrane-water partition coefficients could be calculated. Based upon thicknesses of natural and synthetic membranes, theoretical approximations of diffusion rates were found using lag time calculations.

Effects of Molybdenum Disulfide on Elastomer Flex Life and Other Properties

The addition of 15–20 phr MoS2 to a typical radial tire compound provides significant benefits in processing, tack, physical properties, adhesion, and flex crack growth with minimal effects on cure, compression set, ozone resistance, weatherometer aging, or heat buildup. Although lower-cost additives are available that can provide a similar benefit in each area, few provide such multiple benefits.