Human mutations in high-confidence Tourette disorder genes affect sensorimotor behavior, reward learning, and striatal dopamine in mice

Tourette disorder (TD) is poorly understood, despite affecting 1/160 children. A lack of animal models possessing construct, face, and predictive validity hinders progress in the field. We used CRISPR/Cas9 genome editing to generate mice with mutations orthologous to human de novo variants in two high-confidence Tourette genes, CELSR3 and WWC1. Mice with human mutations in Celsr3 and Wwc1 exhibit cognitive and/or sensorimotor behavioral phenotypes consistent with TD. Sensorimotor gating deficits, as measured by acoustic prepulse inhibition, occur in both male and female Celsr3 TD models. Wwc1 mice show reduced prepulse inhibition only in females. Repetitive motor behaviors, common to Celsr3 mice and more pronounced in females, include vertical rearing and grooming. Sensorimotor gating deficits and rearing are attenuated by aripiprazole, a partial agonist at dopamine type II receptors. Unsupervised machine learning reveals numerous changes to spontaneous motor behavior and less predictable patterns of movement. Continuous fixed-ratio reinforcement shows that Celsr3 TD mice have enhanced motor responding and reward learning. Electrically evoked striatal dopamine release, tested in one model, is greater. Brain development is otherwise grossly normal without signs of striatal interneuron loss. Altogether, mice expressing human mutations in high-confidence TD genes exhibit face and predictive validity. Reduced prepulse inhibition and repetitive motor behaviors are core behavioral phenotypes and are responsive to aripiprazole. Enhanced reward learning and motor responding occur alongside greater evoked dopamine release. Phenotypes can also vary by sex and show stronger affection in females, an unexpected finding considering males are more frequently affected in TD.

Human mutations in high-confidence Tourette disorder genes affect sensorimotor behavior, reward learning, and striatal dopamine in mice

Tourette disorder (TD) is poorly understood, despite affecting 1/160 children. A lack of animal models possessing construct, face, and predictive validity hinders progress in the field. We used CRISPR/Cas9 genome editing to generate mice with mutations orthologous to human de novo variants in two high-confidence Tourette genes, CELSR3 and WWC1 . Mice with human mutations in Celsr3 and Wwc1 exhibit cognitive and/or sensorimotor behavioral phenotypes consistent with TD. Sensorimotor gating deficits, as measured by acoustic prepulse inhibition, occur in both male and female Celsr3 TD models. Wwc1 mice show reduced prepulse inhibition only in females. Repetitive motor behaviors, common to Celsr3 mice and more pronounced in females, include vertical rearing and grooming. Sensorimotor gating deficits and rearing are attenuated by aripiprazole, a partial agonist at dopamine type II receptors. Unsupervised machine learning reveals numerous changes to spontaneous motor behavior and less predictable patterns of movement. Continuous fixed-ratio reinforcement shows Celsr3 TD mice have enhanced motor responding and reward learning. Electrically evoked striatal dopamine release, tested in one model, is greater. Brain development is otherwise grossly normal without signs of striatal interneuron loss. Altogether, mice expressing human mutations in high-confidence TD genes exhibit face and predictive validity. Reduced prepulse inhibition and repetitive motor behaviors are core behavioral phenotypes and are responsive to aripiprazole. Enhanced reward learning and motor responding occurs alongside greater evoked dopamine release. Phenotypes can also vary by sex and show stronger affection in females, an unexpected finding considering males are more frequently affected in TD.

Significance Statement

We generated mouse models that express mutations in high-confidence genes linked to Tourette disorder (TD). These models show sensorimotor and cognitive behavioral phenotypes resembling TD-like behaviors. Sensorimotor gating deficits and repetitive motor behaviors are attenuated by drugs that act on dopamine. Reward learning and striatal dopamine is enhanced. Brain development is grossly normal, including cortical layering and patterning of major axon tracts. Further, no signs of striatal interneuron loss are detected. Interestingly, behavioral phenotypes in affected females can be more pronounced than in males, despite male sex bias in the diagnosis of TD. These novel mouse models with construct, face, and predictive validity provide a new resource to study neural substrates that cause tics and related behavioral phenotypes in TD.

The evolutionary history of ACE2 usage within the coronavirus subgenus Sarbecovirus

Severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and SARS-CoV-2 are not phylogenetically closely related; however, both use the angiotensin-converting enzyme 2 (ACE2) receptor in humans for cell entry. This is not a universal sarbecovirus trait; for example, many known sarbecoviruses related to SARS-CoV-1 have two deletions in the receptor binding domain of the spike protein that render them incapable of using human ACE2. Here, we report three sequences of a novel sarbecovirus from Rwanda and Uganda that are phylogenetically intermediate to SARS-CoV-1 and SARS-CoV-2 and demonstrate via in vitro studies that they are also unable to utilize human ACE2. Furthermore, we show that the observed pattern of ACE2 usage among sarbecoviruses is best explained by recombination not of SARS-CoV-2, but of SARS-CoV-1 and its relatives. We show that the lineage that includes SARS-CoV-2 is most likely the ancestral ACE2-using lineage, and that recombination with at least one virus from this group conferred ACE2 usage to the lineage including SARS-CoV-1 at some time in the past. We argue that alternative scenarios such as convergent evolution are much less parsimonious; we show that biogeography and patterns of host tropism support the plausibility of a recombination scenario, and we propose a competitive release hypothesis to explain how this recombination event could have occurred and why it is evolutionarily advantageous. The findings provide important insights into the natural history of ACE2 usage for both SARS-CoV-1 and SARS-CoV-2 and a greater understanding of the evolutionary mechanisms that shape zoonotic potential of coronaviruses. This study also underscores the need for increased surveillance for sarbecoviruses in southwestern China, where most ACE2-using viruses have been found to date, as well as other regions such as Africa, where these viruses have only recently been discovered.

Are we underestimating the quality of aviremic hepatitis C-positive kidneys? Time to reconsider

Kidney Donor Risk Index (KDRI) introduced in 2009 included hepatitis C serologic but not viremic status of the donors. With nucleic acid amplification testing (NAT) now being mandatory, further evaluation of these donors is possible. We conducted a retrospective matched case-control analysis of adult deceased donor kidney transplants performed between December 5, 2014 to December 31, 2016 with the KDRI score and hepatitis C virus antibody (HCV Ab) and NAT testing status obtained from the United Network for Organ Sharing database. The 205 aviremic HCV Ab+ NAT - kidney transplants were compared to KDRI matched control kidneys that were HCV Ab-NAT-. The aviremic HCV kidneys were recovered from donors who were significantly younger, more likely to be white, and less likely to have hypertension and diabetes. The majority of the recipients of the aviremic HCV kidneys when compared to matched controls were HCV positive: 90.2% vs 4.3%. The recipients were significantly older, were on dialysis for a shorter time, and were transplanted sooner. The graft survival of aviremic HCV kidneys was similar (P < .08). If the HCV status of the aviremic kidneys was assumed to be negative, 122 more kidneys could have been allocated to patients with estimated posttransplant survival <20. Seven kidneys would no longer have Kidney Donor Profile Index >85%. Further policies might consider these findings to appropriately allocate these kidneys.

Unintended Consequences in Use of Increased Risk Donor Kidneys in the New Kidney Allocation Era

BACKGROUND

The new kidney allocation system (KAS) intends to allocate the top 20% of kidneys to younger recipients with longer life expectancy. We hypothesized that the new KAS would lead to greater allocation of Public Health Service (PHS) increased-risk donor organs to younger recipients.

METHODS

Analyses of the Organ Procurement and Transplantation Network data of patients who underwent primary deceased kidney transplantation were performed in pre- and post-KAS periods.

RESULTS

The allocation of PHS increased-risk kidney allografts in various age groups changed significantly after implementation of the new KAS, with an increased proportion of younger individuals receiving increased-risk kidneys (7% vs 10% in age group 20-29 y and 13% vs 18% in age group 30-39 y before and after KAS, respectively; P < .0001). This trend was reversed in recipients 50-59 years old, with 31% in the pre-KAS period compared with 26% after KAS (P < .0001).

CONCLUSIONS

The new KAS resulted in a substantial increase in allocation of PHS increased-risk kidneys to candidates in younger age groups. Because increased-risk kidneys are generally underutilized, future efforts to optimize the utilization of these organs should target younger recipients and their providers.

Lead in ammunition: a persistent threat to health and conservation

Many scavenging bird populations have experienced abrupt declines across the globe, and intensive recovery activities have been necessary to sustain several species, including the critically endangered California condor (Gymnogyps californianus). Exposure to lead from lead-based ammunition is widespread in condors and lead toxicosis presents an immediate threat to condor recovery, accounting for the highest proportion of adult mortality. Lead contamination of carcasses across the landscape remains a serious threat to the health and sustainability of scavenging birds, and here we summarize recent evidence for exposure to lead-based ammunition and health implications across many species. California condors and other scavenging species are sensitive indicators of the occurrence of lead contaminated carcasses in the environment. Transdisciplinary science-based approaches have been critical to managing lead exposure in California condors and paving the way for use of non-lead ammunition in California. Similar transdisciplinary approaches are now needed to translate the science informing on this issue and establish education and outreach efforts that focus on concerns brought forth by key stakeholders.

Identification of differentially expressed thyroid hormone responsive genes from the brain of the Mexican Axolotl (Ambystoma mexicanum)

The Mexican axolotl (Ambystoma mexicanum) presents an excellent model to investigate mechanisms of brain development that are conserved among vertebrates. In particular, metamorphic changes of the brain can be induced in free-living aquatic juveniles and adults by simply adding thyroid hormone (T4) to rearing water. Whole brains were sampled from juvenile A. mexicanum that were exposed to 0, 8, and 18 days of 50 nM T4, and these were used to isolate RNA and make normalized cDNA libraries for 454 DNA sequencing. A total of 1,875,732 high quality cDNA reads were assembled with existing ESTs to obtain 5884 new contigs for human RefSeq protein models, and to develop a custom Affymetrix gene expression array (Amby_002) with approximately 20,000 probe sets. The Amby_002 array was used to identify 303 transcripts that differed statistically (p<0.05, fold change >1.5) as a function of days of T4 treatment. Further statistical analyses showed that Amby_002 performed concordantly in comparison to an existing, small format expression array. This study introduces a new A. mexicanum microarray resource for the community and the first lists of T4-responsive genes from the brain of a salamander amphibian.

Diverse types of interneurons generate thalamus-evoked feedforward inhibition in the mouse barrel cortex

Sensory information, relayed through the thalamus, arrives in the neocortex as excitatory input, but rapidly induces strong disynaptic inhibition that constrains the cortical flow of excitation both spatially and temporally. This feedforward inhibition is generated by intracortical interneurons whose precise identity and properties were not known. To characterize interneurons generating feedforward inhibition, neurons in layers IV and V of mouse somatosensory ("barrel") cortex in vitro were tested in the cell-attached configuration for thalamocortically induced firing and in the whole-cell mode for synaptic responses. Identification as inhibitory or excitatory neurons was based on intrinsic firing patterns and on morphology revealed by intracellular staining. Thalamocortical stimulation evoked action potentials in approximately 60% of inhibitory interneurons but in <5% of excitatory neurons. The inhibitory interneurons that fired received fivefold larger thalamocortical inputs compared with nonfiring inhibitory or excitatory neurons. Thalamocortically evoked spikes in inhibitory interneurons followed at short latency the onset of excitatory monosynaptic responses in the same cells and slightly preceded the onset of inhibitory responses in nearby neurons, indicating their involvement in disynaptic inhibition. Both nonadapting (fast-spiking) and adapting (regular-spiking) inhibitory interneurons fired on thalamocortical stimulation, as did interneurons expressing parvalbumin, calbindin, or neither calcium-binding protein. Morphological analysis revealed that some interneurons might generate feedforward inhibition within their own layer IV barrel, whereas others may convey inhibition to upper layers, within their own or in adjacent columns. We conclude that feedforward inhibition is generated by diverse classes of interneurons, possibly serving different roles in the processing of incoming sensory information.

MSH6 and MSH3 are rarely involved in genetic predisposition to nonpolypotic colon cancer

A set of 90 nonpolypotic colon cancer families in which germ-line mutations of MSH2 and MLH1 had been excluded were screened for mutations in two additional DNA mismatch repair genes, MSH6 and MSH3. Kindreds fulfilling and not fulfilling the Amsterdam I criteria, showing early and late onset colorectal (and other) cancers, and having microsatellite stable and unstable tumors were included. Two partly parallel approaches were used: genetic linkage analysis (19 large families) and the protein truncation test (85, mostly smaller, families). Whereas MSH3 was not involved in any family, a large Amsterdam-positive, late-onset family showed a novel germ-line mutation in MSH6 (deletion of CT at nucleotide 3052 in exon 4). The mutation was identified through genetic linkage (multipoint lod score 2.4) and subsequent sequencing of MSH6. Furthermore, the entire MSH6 gene was sequenced exon by exon in families with frameshift mutations in the (C)8 tract in tumors, previously suggested as a predictor of MSH6 germ-line mutations; no mutations were found. We conclude that germ-line involvement of MSH6 and MSH3 is rare and that other genes are likely to account for a majority of MSH2-, MLH1-mutation negative families with nonpolypotic colon cancer.

Candidate tumor suppressor RIZ is frequently involved in colorectal carcinogenesis

The distal portion of chromosome 1p is one of the most commonly affected regions in human cancer. In this study of hereditary and sporadic colorectal cancer, a region of frequent deletion was identified at 32.2 centimorgans from 1ptel. Deletion breakpoints clustered in the vicinity of or inside the gene RIZ, which encodes a retinoblastoma protein-interacting zinc finger protein. Sequence analysis revealed frequent frameshift mutations of the RIZ gene. The mutations consisted of 1- or 2-bp deletions of a coding (A)(8) or (A)(9) tract and were confined to microsatellite-unstable colorectal tumors, being present in 9 of 24 (37.5%) primary tumors and in 6 of 11 (54.5%) cell lines; in 2 cell lines the mutation was homozygous/hemizygous. The mutations apparently were selected clonally in tumorigenesis, because similar poly(A) tracts in other genes were not affected. Two alternative products of the gene exist, RIZ1, which contains a PR (PRDI-BF1-RIZ1) domain implicated in tumor suppressor function, and RIZ2, which is lacking this motif. Furthermore, the C-terminal region, which contains the poly(A) tracts, includes a PR-binding motif, possibly mediating interactions with other proteins or with RIZ itself (oligomerization). Four of eleven microsatellite-unstable colorectal cancer cell lines, three of which had frameshifts, showed reduced or absent mRNA expression of RIZ1. In a cell line that is homozygous/hemizygous for the typical frameshift mutation, immunoblotting showed truncated RIZ protein, whereas adenovirus-mediated RIZ1 expression caused G(2)/M arrest and apoptosis. We propose that RIZ is a target of the observed 1p alterations, with impairment of the PR domain-mediated function through either frameshift mutation or genomic deletion.

Polymorphic variation at the BAT-25 and BAT-26 loci in individuals of African origin. Implications for microsatellite instability testing

Instability in the repeat size of microsatellite sequences has been described in both hereditary nonpolyposis and sporadic colorectal cancers. Tumors expressing microsatellite instability are identified through the comparison of the repeat sizes at multiple microsatellite loci between tumor and matched normal tissue DNA. The use of a five-marker panel including two mononucleotide repeat microsatellites, BAT-25 and BAT-26, has recently been suggested for the clinical determination of tumor microsatellite instability. The BAT-25 and BAT-26 loci included in this panel have both demonstrated sensitivity to microsatellite instability and normal quasimonomorphic allelic patterns, which has simplified the distinction between normal and unstable alleles. However, in this study, we identified allelic variations in the size of the poly(A) tract at BAT-26 in 12.6% of 103 healthy African-Americans screened. In addition, 18.4% exhibited allelic size variations in the poly(T) tract at BAT-25. Finally, 2.9% showed variant alleles at both BAT-25 and BAT-26 loci. Screening a small population of Nigerians confirmed the polymorphic nature of both loci and the ethnic origin of alleles not identified in other populations studied thus far. Our results dispute the quasimonomorphic nature of both BAT-25 and BAT-26 in all populations and support the need for thorough population studies to define the different allelic profiles and frequencies at microsatellite loci.

Comparison of danofloxacin with baquiloprim/sulphadimidine for the treatment of experimentally induced Escherichia coli diarrhoea in calves

Thirty-eight, one- to two-week-old calves with experimentally induced Escherichia coli diarrhoea were randomly assigned to three treatment groups. Two groups of 15 calves were treated intramuscularly once daily for three days with either danofloxacin mesylate at 1.25 mg/kg bodyweight, or with baquiloprim/sulphadimidine as a positive control (10 mg of combined active ingredient/kg); eight calves were treated with 0.9 per cent sodium chloride solution as a negative control (1 ml/20 kg). Faecal consistency, demeanour, hydration status, appetite and bodyweight were monitored before, during, and for four days after treatment by an investigator unaware of the animals' treatment. Before treatment, the clinical, biochemical, and faecal indices were similar among the groups. By 24 hours after treatment began, the proportion of observations of faeces recorded as of normal consistency was highest in the danofloxacin-treated group (26 of 60), compared with 16 of 60 in the baquiloprim/sulphadimidine treated groups and four of 32 in the control group. The proportion of calves with a normal demeanour was highest in the danofloxacin-treated group at all the evaluations and these calves gained significantly (P < 0.05) more weight (1.6 [0.27] kg) than the calves treated with baquiloprim/sulphadimidine (0.67 [0.36] kg). The calves in the danofloxacin-treated group maintained relatively normal blood pH values, whereas the calves in the control group became progressively acidotic. By the end of treatment, the mean bicarbonate concentration was significantly (P < 0.05) higher in the danofloxacin-treated calves than in the control group. The pH of the calves in the baquiloprim/sulphadimidine-treated group changed little during treatment, but by three days after the last treatment their mean pH had dropped to the level of the calves in the control group. The mean bicarbonate concentration of the baquiloprim/sulphadimidine-treated calves, like that of the danofloxacin-treated calves, was significantly (P < 0.05) higher than that of the calves in the control group.

Reorientations in the bacteriorhodopsin photoscycle are pH dependent

Chromophore reorientations during the bacteriorhodopsin photocycle in the purple membrane of Halobacterium salinarium have been detected by time-resolved linear dichroism measurements of the optical anisotropy over the pH range from 4 to 10 and at ionic strengths from 10 mM to 1 M. The results show that reorientations in the L and M states of bacteriorhodopsin are pH dependent, reaching their largest amplitude when the membrane is at pH 6-8. Reorientations on the millisecond time scale of unexcited spectator proteins in the native purple membrane also depend on pH, consistent with the suggestion that spectator reorientations are triggered by reorientation of the photoexcited protein. The results imply that a group with a PK(a) of 5 to 6 enables reorientations, and that the deprotonation of a site at pH values above 9 restricts reorientational motion. This suggests that reorientations in M may be correlated with proton release.

Efficacy of florfenicol for treatment of clinical and subclinical bovine mastitis

OBJECTIVE

To evaluate efficacy of florfenicol treatment for bovine mastitis caused by Streptococcus agalactiae, Staphylococcus aureus nonagalactiae streptococci, coagulase-negative staphylococci, Escherichia coli, Klebsiella sp, and others.

DESIGN

Double blind study with cases randomly assigned to 1 of 2 treatment groups.

SAMPLE POPULATION

861 cows/10 commercial dairy farms.

PROCEDURE

Experimental (750 mg of florfenicol) or control (200 mg of cloxacillin) treatment was administered by intramammary infusion every 12 hours for 3 treatment to all cases. Treatments were randomly assigned identified only by numerical labels. To retain blinding, the longer withdrawal time was adhered to for all cases. Cases remained in the study only if there was no other treatment. Quarter samples were recultured 14, 21, and 28 days later. If all samples after day 1 were culture negative, the case was defined as cured. If only 1 of the follow-up results was positive, the case was considered cured if the day-28 somatic cell count was < 300,000/ ml. Failure of treatment was defined as 2 or more culture positive follow-up samples.

RESULTS

Florfenicol and cloxacillin did not differ significantly in efficacy versus clinical (n = 85) or subclinical (n = 71) bovine mastitis, or for any etiologic agent (X2). Overall cure rates for mastitis were: Str agalactiae, 5 of 8 (63%); Sta aureus, 5 of 54 (9%); Streptococcus sp, 16 of 35 (46%); Staphylococcus sp, 7 of 33 (21%); E coli, 5 of 11 (46%); Klebsiella sp, 3 of 6 (50%); others, 1 of 9 (11%); and all cases, 42 of 156 (27%).

CONCLUSIONS

Florfenicol did not offer any advantage over cloxacillin in efficacy against bovine mastitis. Overall cure rates were low. As with most mastitis treatment regimens poor efficacy may be partly attributable to the short duration of treatment.

E.J. Curran, M.D., D. Ophth. An historical vignette

An historical vignette recounting the life of E.J. Curran, M.D., from his beginnings in Australia to his medical education at some of the most prestigious institutions of that era. His significant contributions as chairman of the University of Kansas Department of Ophthalmology are discussed. He became a national figure in ophthalmology when he elucidated the pathophysiology behind pupillary block glaucoma and the reason peripheral iridotomy would permanently relieve this condition.

Reorientations in the bacteriorhodopsin photocycle

Reversible photoinduced reorientations of bacteriorhodopsin have been detected in suspensions of the purple membrane of Halobacterium salinarium. The anisotropy in bacteriorhodopsin during the nanosecond through millisecond stages of the photocycle was measured by time-resolved linear dichroism and transient absorption measurements. From these measurements the anisotropies of the K, L, M, and O intermediates were determined and related to the chromophore orientation with respect to the initially selected orientation. The anisotropies of the K and L states are 0.38 +/- 0.01 and 0.35 +/- 0.01, respectively. Further anisotropy decay after formation of the M intermediate in about 0.5 ms is evidence of orientational motion at this stage in the photocycle. A constant anisotropy with a value of 0.39 +/- 0.02 in the O intermediate demonstrates a recovery of the initial protein orientation with the formation of the O state. These results demonstrate that reorientations in BR are photoinduced and reversible. Similar measurements for L and M were carried out for purple membrane in polyacrylamide gels, where the anisotropies in the L and M states are 0.38 +/- 0.014 and 0.36 +/- 0.01, respectively. These results show that reorientations also occur in BR immobilized in gels. Anisotropy decay in the M state after formation of the M intermediate was not detected in the gels, in contrast to the M intermediate in suspensions. Orientational changes are observed for BR in purple membrane suspensions in the K state, during the K-->L step, in the M state possibly related to an M1-->M2 transition, and in the O state, where an almost complete return to the original orientation occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

Light-induced reorientation in the purple membrane

Reorientation of bacteriorhodopsin in the native purple membrane was studied by time-resolved linear dichroism spectroscopy (TRLD) over the millisecond time regime. The time responses observed in TRLD are distinctly different from the isotropic transient absorption (TA) at wavelengths in the range 550-590 nm, where the bacteriorhodopsin ground state absorbs. In contrast, the TA and TRLD responses have nearly identical time dependence at 410 and 690 nm, where the intermediates M and O, respectively, principally contribute. These results demonstrate ground-state bacteriorhodopsin reorientation triggered by the photocycle. The TRLD and TA data are analyzed to test models for reorientational motion. Rotational diffusion of ground-state bacteriorhodopsin cannot account for the details of the data. Rather, the results are shown to be consistent with a reversible reorientation of "spectator" (nonexcited) members of the bacteriorhodopsin trimer in the purple membrane in response to the photocycling member of the trimer. This response may be associated with cooperativity in the trimer.

Conformational motion in bacteriorhodopsin: the K to L transition

By comparison of the time dependence of linear dichroism and transient absorption in light-adapted bacteriorhodopsin over the first 10 microseconds following excitation, conformational motion in the protein has been detected. Time-resolved linear dichroism and transient absorption scans are reported for several wavelengths that probe the K610 and L550 intermediates in the bacteriorhodopsin photocycle. The transient absorption scans are insensitive to conformational motion and yield the lifetimes of the K610 and L550 intermediates. In contrast, the time-resolved linear dichroism scans demonstrate orientational motion of the chromophore with a 1.7-microsecond rotational time. The wavelength dependence of the least-squares fitting parameters establishes that this motion is associated with L550. This motion is discussed in relation to a protein conformational change in the course of the bacteriorhodopsin photocycle. No evidence is observed for orientational motion on the time scale of the L550----M410 transition.

Predictors of trough serum gentamicin concentrations in neonates

Neonates admitted to an intensive care nursery frequently receive gentamicin sulfate therapy. This study was undertaken to determine predictors of an elevated (greater than or equal to 2 mg/L) trough serum concentration of gentamicin sulfate (undesirable because of potential toxic effects). A total of 140 infants with birth weight of 496 to 4545 g and gestational age of 23 to 42 weeks who received gentamicin in the first days of life were studied prospectively. The trough serum concentration of gentamicin was not significantly affected by concurrent use of dopamine hydrochloride, indomethacin, furosemide, or umbilical artery catheters. Of 11 infants weighing between 1000 and 1500 g on an 18-hour dosing interval, 55% had trough serum gentamicin concentration of 2 mg/L or more. Use of the recommended 24-hour dosing interval for infants weighing less than 1000 g and an 18-hour schedule for preterm infants weighing more than 1000 g resulted in a significant number of elevated trough serum gentamicin concentrations in the latter. A dosing interval of 24 hours for infants less than 1500 g and 18 hours in infants between 1500 and 3250 g is suggested.

Laboratory comparisons of five seed-trap designs for dry, windy environments

Five seed-trap designs were tested for relative seed-trapping ability in a wind tunnel. Seeds of 12 plant species were blown over random combinations of seed-trap designs with an average wind speed of 16 km∙h−1. Results showed significant effects of seed-trap design on the number of seeds collected by the traps. Seed traps simulating the ground surface (gravel, marbles, loose soil) caught significantly (P < 0.05) fewer seeds than those simulating soil depressions or holes (glued dirt, funnel). Gravel surfaces trapped significantly (P < 0.05) more seeds than the surfaces with marbles. Results of this study may be used in the selection of seed traps for use in the field where sticky surfaces are unsuitable because of drying and dust.

Picosecond resonance Raman evidence for unrelaxed heme in the (carbonmonoxy)myoglobin photoproduct

An actively and passively mode-locked Nd:YAG laser, producing 30-ps pulses of 1-mJ energy at 532 nm, has been used to photolyze (carbonmonoxy)myoglobin (MbCO) and generate its resonance Raman spectrum, which was recorded with a vidicon multichannel analyzer. The photoproduct spectrum was obtained by subtraction of the MbCO spectrum, obtained at lower incident power levels. Comparison with the spectrum of deoxyMb, obtained with the same apparatus, revealed frequency downshifts of approximately 4 cm-1, for bands at 1604, 1554, and 1542 cm-1, which are identified with porphyrin skeletal modes v10, v19, and v11. These frequencies are known to correlate inversely with the core size of the porphyrin ring, and the shifts imply a larger core size for the photoproduct than for deoxyMb. Similar shifts have been observed for the (carbonmonoxy)hemoglobin (HbCO) photoproduct; in that case, the shifts persist for longer than 20 ns, whereas they are absent in the MbCO photoproduct spectrum within 7 ns of photolysis. The unrelaxed state of the heme group region is therefore suggested to be maintained by protein forces, which relax more rapidly for Mb than Hb. This may reflect a tighter coupling in Hb of the out-of-plane movement of the Fe atom with the proximal histidine-containing F helix.

Evaluation of the teratogenic potential of delalutin (17 alpha-hydroxyprogesterone caproate) in mice

Swiss Webster female mice weighing 25-30 gm were injected subcutaneously on days 6-15 of gestation with the synthetic sex steroid Delalutin (17 alpha-hydroxyprogesterone caproate). Treatment was given daily in doses ranging from 42 to 833 mg/kg body weight, or 10, 100, and 200 times the human therapeutic dose. On day 18 fetuses were removed from the uterus and examined for malformations and other fetotoxic effects. Prenatal treatment with the two higher doses resulted in 8 and 13% maternal deaths, and all doses resulted in a slight increase (4-12% above control) in resorption frequency. Treatment with Delalutin did not significantly affect intrauterine growth, sex ratio, or malformation rate of the offspring. The results of the present study confirm other reports that Delalutin is not androgenic, and that it, like progesterone and certain other sex steroids, does not alter the development of nonreproductive organs.

Health, laxation, and food habit influences on fiber intake of older women

Fifty-nine elderly women interviewed about their food behavior, health, and laxation showed mean dietary fiber (DF) intakes of 14 gm. per day (range 3 to 34 gm. per day). DF intakes were lower for those in poor health and those with a tendency to constipation who took laxatives than for those who did not take laxatives or had no tendency to constipation. Factors not related to DF intake included age, participation in a meal program, living arrangements, understanding of fiber, and functional health. Cooked vegetables and bread added most to DF intakes.

Implications for adult roles from differential styles of mother-infant bonding: an ethological study

Ethological observations of maternal and infant behaviors of nine vervet monkey pairs (Cercopithecus aethiops sabaeus) showed the effects of differential styles of early maternal responsiveness on later infant competence. Those infants receiving the least amount of maternal responsiveness and the most time-off the mother in the first 3 months of development were more socially competent at 6 months of age. The results are discussed within current ethological "attachment" theories. The detachment or separation process of mother-infant interaction is considered as important a factor during infant development as the primary maternal bond.

Cytotoxicity of Mycoplasma pneumoniae Membranes

Organ cultures of adult hamster trachea were used to evaluate the cytotoxic potential of cell fractions of Mycoplasma pneumoniae . Cytoplasm was essentially devoid of activity, whereas viable cells and membrane preparations, at a level of 25 μg of protein per ml, induced necrosis. Damage, as revealed by light and electron microscopy, included ciliostasis, vacuolization, loss of ciliated respiratory epithelial cells, disorganization, and a loss of polarity. Dose response data indicated that the speed and degree of cytotoxicity was directly related to the concentration of membranes. Doses of 30 to 60 μg of protein per ml could reduce relative ciliary activity to 20% of the control level within 4 days. Membranes prepared after freeze-thaw lysis of cells were almost twice as active as those isolated after a combination of osmotic and sonic shock. Membranes of M. fermentans were inactive, though both the FH and M129 strains of M. pneumoniae were toxic. These data indicate that the toxic factor responsible for M. pneumoniae may be located in the cell membrane.