Dose regimen adjustment for milrinone in congestive heart failure patients with moderate and severe renal failure

This study was designed to test a proposed dose modification for intravenous milrinone in congestive heart failure patients (CHF, NYHA I-II) with either moderate or severe renal impairment. All the patients were administered an intravenous loading dose of drug at 50 micrograms kg-1 over 10 min. This was followed by an 18 h maintenance infusion of milrinone at 0.45 or 0.35 micrograms kg-1 min-1 for the moderate (chromium-EDTA clearance of 31-75 mL min-1, n = 10) and severe renally impaired subjects (chromium-EDTA of clearance 10-30 mL min-1, n = 11), respectively. Plasma and urine samples were collected for up to 34 h and analysed for parent drug by validated HPLC methods. The mean (+/- s.d.) steady-state plasma concentrations of milrinone were within the therapeutic range (100-300 ng mL-1) for both groups, with values of 239 +/- 71 ng mL-1 and 269 +/- 32 ng mL-1 for the moderate and severe patients, respectively. No statistical differences were observed between the steady-state values for the two groups. With the exception of two patients per group, individual steady-state levels were also within the therapeutic range. Those outside the nominal range showed steady-state levels, ranging between 308 and 353 ng mL-1, that were not associated with any serious adverse events.(ABSTRACT TRUNCATED AT 250 WORDS)

Linkage mapping in Papio baboons: conservation of a syntenic group of six markers on human chromosome 1

We have established multipoint genetic linkage among six loci in baboons (Papio hamadryas). Published PCR primers designed to amplify five human microsatellite loci were used to amplify homologous loci in 229 pedigreed baboons. Southern blotting was used to type two RFLPs in a functional gene (anti-thrombin III) in a subset of those animals. All six loci are known to map to human chromosome 1q, a region of the genome predicted by karyotype studies to be conserved in baboons. Pairwise recombination frequencies and lod scores indicate that the six loci are also linked in baboons. Recombination distances among the loci are similar to those reported for humans. Like humans, the baboons exhibit higher rates of recombination in females than in males. This study demonstrates that (1) microsatellite loci first described and characterized in the human genome can be effectively used for genetic linkage mapping in non-human primates, (2) a group of genetic loci known to be linked on human chromosome 1q are also linked in the baboon genome, and (3) sex differences in recombination frequencies among loci on human chromosome 1q are also observed in the genome of this Old World monkey. This constitutes the first reported multipoint linkage map in any nonhuman primate.

Binding stoichiometry of the cytotoxic T lymphocyte-associated molecule-4 (CTLA-4). A disulfide-linked homodimer binds two CD86 molecules

CD28 and CTLA-4 are homologous T cell receptors of the immunoglobulin (Ig) superfamily, which bind B7 molecules (CD80 and CD86) on antigen-presenting cells and transmit important costimulatory signals during T cell activation. Here we have investigated the subunit structure of CTLA-4 and the stoichiometry of its binding to B7 molecules. We demonstrate CTLA-4 is a homodimer interconnected by one disulfide bond in the extracellular domain at cysteine residue 120. Each monomeric polypeptide chain of CTLA-4 contains a high affinity binding site for B7 molecules; soluble CTLA-4 and CD86 form complexes containing equimolar amounts of monomeric CTLA-4 and CD86 (i.e. a 2:2 molecular complex). Thus, CTLA-4 and probably CD28 have a receptor structure consisting of preexisting covalent homodimers with two binding sites. Dimerization of CTLA-4 and CD28 is not required for B7 binding, nor is it sufficient to trigger signaling.

Phospholipase A2 engineering. Probing the structural and functional roles of N-terminal residues with site-directed mutagenesis, X-ray, and NMR

The N-terminal residues of phospholipase A2 (PLA2) are believed to be involved in the hydrogen-bonding network, the interfacial binding site, or the hydrophobic channel. Site-directed mutants of bovine pancreatic PLA2 with substitutions at positions 2, 3, 4, 5, 6, and 9 were constructed to test the roles of these residues in the structure and function of PLA2. Nonconservative mutations of Phe-5 and Ile-9, which are located inside the hydrophobic channel, led to significant perturbations in the conformation and conformational stability. Kinetic studies also indicated that mutations at Ile-9 and Phe-5 caused significant decreases in the rate of hydrolysis toward micellar and vesicle substrates. Scooting mode kinetic analysis showed that the binding step of the mutant enzymes to the DC14PM (1,2-dimyristoyl-sn-glycero-3-phosphomethanol) vesicle interface is not significantly affected and that the perturbations in catalysis occur mainly in kcat at the interface. The results taken together suggest that the residues Ile-9 and Phe-5 are important for both structure and catalysis. The mutant W3A (Trp-3 to Ala) also showed decreased rates of hydrolysis but to a lesser extent than Ile-9 and Phe-5 mutants. In addition, the binding affinity of W3A to the surface of the vesicles (i.e., the E to E* step) has been perturbed to the extent that hopping between anionic vesicles has been observed. On the other hand, the mutants of Gln-4 and Asn-6, which are located at or near the surface, displayed structural and kinetic properties similar to those of the wild-type PLA2 with the exception of the highly hydrophilic lysine mutant. The X-ray structure of the Q4E mutant indicates that the overall structure, the catalytic triad, and the link between residue 4 and Asp-99 via hydrogen bonding through Ala-1 and the structural water remain the same as in the WT. Substitutions for Leu at position 2 showed an acyl chain length discrimination toward different substrates, which may reflect the contacting position(s) of the substrate acyl chain with Leu-2.

Characteristics of police referrals to a psychiatric emergency unit in Australia

The study examined characteristics of patients referred by police to a psychiatric emergency unit on the campus of a 400-bed psychiatric hospital in Adelaide, South Australia. Of all police referrals (N = 634) during a 21-month period, 437 cases were admitted to the hospital. Most police referrals were young, single, unemployed men. In a subsample of 61 patients, 72 percent had previous psychiatric admissions and 39 percent had been previously referred by police. Compared with nonpsychotic subjects, psychotic subjects used more mental health resources, had a longer index admission, and after the index discharge relapsed more rapidly and spent more days in the hospital.

Agenesis of permanent maxillary lateral incisors in South Australian twins

The frequency of agenesis of maxillary lateral incisors (I2) in a sample of South Australian twins was determined, and associations with gender, zygosity, birthweight and dental crown size were investigated. Ten of the 446 twins examined (2.24 per cent) displayed agenesis of one or both I2, a similar frequency to that reported for Australian singletons. Seven of the ten affected individuals were monozygous female twins, including two pairs, while the three affected dizygous twins were each from different male twin pairs. Five pairs of monozygous twins were identified who displayed varying expressions of normal, small, peg-shaped or missing I2. These twin pairs displayed disparate birthweights suggesting they may have been mono-chorionic. These findings are consistent with a multifactorial threshold model linking size and number of I2 with developmental influences modifying phenotypic expression in those monozygous twins whose genetic predisposition places them near to the threshold for agenesis.

The CLASS program: self-directed care

Many issues surround self-directed care, and individuals who need habilitation services have brought those issues to the fore in recent years. The Visiting Nurse Association of Texas participates in a program with the state of Texas that allows individuals with disabilities to direct their own care while it also ensures that safety measures are addressed. The program is a success on many fronts.

Inflammation as a pathogenic mechanism in Alzheimer's disease

Numerous markers of inflammation have been reported in the Alzheimer's disease brain. Although other pathogenic mechanisms certainly apply, there is now compelling evidence that inflammation is not simply a response to already existing Alzheimer's pathology, but ultimately becomes a significant source of pathology. The pathogenic potential of inflammation in Alzheimer's disease follows from the inherent destructiveness of inflammatory mechanisms, the postmitotic status of neurons, and the unique interactions of inflammatory markers and cells with pathologic hallmarks of Alzheimer's such as amyloid beta-peptide. These conclusions from basic science are borne out by recent clinical efforts, though the latter are still limited and require further confirmation.

Adjuvant intraoperative photodynamic therapy in experimental colorectal cancer

A reliable animal model for quantitative assessment of local recurrence of colorectal cancer was developed using colo26 tumour in BALB/c mice. The effect of adjuvant intraoperative photodynamic therapy to potentially curative surgery on local recurrence was examined in four study and four control groups. Study groups received 15 mg kg-1 Photofrin (a photosensitizing drug) 24 h before surgery. After 'curative' tumour excision, the tumour beds were illuminated with either 630 nm or 510 nm laser light each at 40 and 70 J/cm-2. Controls received surgery only, surgery and Photofrin only or surgery and either 630 nm or 510 nm light. The local recurrence rates at 70 days were 17-33 per cent in the study groups compared with 83-100 per cent in the control groups (P < 0.001; log rank test). Photodynamic therapy is capable of reducing local recurrence following potentially curative excision of tumour in this model.

Effect of cisapride on distal colonic motility in the early postoperative period following left colonic anastomosis

PURPOSE

This study was designed to investigate the modulatory effect of cisapride on colonic motility in the postoperative period.

METHODS

A prospective, double-blind, randomized, placebo-controlled trial of 14 patients undergoing left colonic anastomosis was carried out. Manometric probes were positioned with transducers on either side of the anastomosis, and colonic activity was recorded continuously for a median of 98 (range, 72-144) hours using an ambulatory system. Quantitative indices of motility were calculated with an automated analysis program.

RESULTS

Isolated waveform activity returned at a median of 1.8 (interquartile range, 1-3) hours and motor complex activity at 24 (interquartile range, 19-30) hours in the placebo group and at similar times in the cisapride group. All motility variables except mean amplitude increased significantly with time in both groups. In the cisapride group the motility index was significantly increased compared with the placebo group (P = 0.03), resulting from an increase in percentage duration of activity (P = 0.002). Activity index, mean amplitude of waveforms, and number of waves greater than 50 cm H2O did not differ between groups. In contrast to placebo, cisapride significantly increased the median number of waves greater than 13 cm H2O and percentage duration of activity distal to the anastomosis compared with proximally. The return of bowel sounds (median, 43, interquartile range, 24-48 hours vs. 67, 29-69 hours; P = 0.2) or first passage of flatus (78, 54-94 hours vs. 94, 81-105 hours; P = 0.1) did not differ between groups.

CONCLUSIONS

Although cisapride may have a differential effect on the colon proximal and distal to an anastomosis and significantly increases some indices of motility in the early postoperative period, these are unlikely to be of any clinical relevance.

Polymerase chain reaction detection of small round-structured viruses from two related hospital outbreaks of gastroenteritis using inosine-containing primers

Two outbreaks of gastroenteritis in the UK which occurred nine days apart at Lymington and Southampton hospitals were investigated. The clinical and epidemiological features of both outbreaks were characteristic of small round-structured virus (SRSV) infection with rapid onset of diarrhoea and/or nausea and vomiting and propagation of the outbreaks by secondary spread. SRSV particles were observed by immune electron microscopy (EM) in 60% of faecal samples from both outbreaks and no other pathogens were detected. The index case for the second outbreak was a patient who was admitted with diarrhoea and vomiting after being discharged from Lymington hospital during the first outbreak. The possibility that the two outbreaks were caused by the same strain of SRSV was investigated by the polymerase chain reaction (PCR). New inosine-containing PCR primers were designed to amplify the RNA polymerase region of SRSV cDNA from genetic groups I and II. The PCR using the group II primers achieved a higher detection rate for SRSVs in faecal samples (68% of samples positive from both outbreaks) than immune EM. SRSVs were not detected using the group I primers or using conventional degenerate PCR primers. The nucleotide sequences of PCR amplicons from both outbreaks were identical providing molecular epidemiological evidence for the involvement of a single SRSV strain. Comparison of the RNA polymerase region of this virus with the equivalent regions of genetic group I (69.4-75.0% amino acid identify) and genetic group II (88.9-100% amino acid and 77.1-88.1% nucleotide identity) SRSVs revealed that the causative SRSV was a distinct member of genetic group II.

Variability of dopamine D4 receptor (DRD4) gene sequence within and among nonhuman primate species

The dopamine D4 receptor is one of five receptors known to function in mammalian dopaminergic pathways. The DNA sequence of the human dopamine D4 receptor gene (DRD4) has previously been investigated in several populations and found to be highly polymorphic at both the DNA and amino acid levels, exhibiting at least 25 alleles. This variation results from differences in the number and DNA sequence of a 48-bp (16-amino acid) repeat unit in the coding region of DRD4. In the present study, DRD4 DNA sequence was examined in at least two individuals from each of five nonhuman primate species. All five species exhibit intraspecies variability, including both single nucleotide substitutions and variation in the number of 48-bp repeat units. No differences were found between the two alleles of one individual from a sixth nonhuman species. Within each species, all of the DRD4 alleles share species-specific features, indicating that while repeat-unit variation is nearly ubiquitous, ancestral variation has been lost and subsequently regenerated in each of the evolutionary lineages studied. Chimpanzees and gorillas share a unique 12-bp deletion in the coding region of DRD4, outside the repeat-unit segment of the gene. This suggest that the extant chimpanzee DRD4 is more closely related to the gorilla DRD4 than either is to the human DRD4.

Infection of a yellow baboon with simian immunodeficiency virus from African green monkeys: evidence for cross-species transmission in the wild

Many African primates are known to be naturally infected with simian immunodeficiency viruses (SIVs), but only a fraction of these viruses has been molecularly characterized. One primate species for which only serological evidence of SIV infection has been reported is the yellow baboon (Papio hamadryas cynocephalus). Two wild-living baboons with strong SIVAGM seroreactivity were previously identified in a Tanzanian national park where baboons and African green monkeys shared the same habitat (T. Kodama, D. P. Silva, M. D. Daniel, J. E. Phillips-Conroy, C. J. Jolly, J. Rogers, and R. C. Desrosiers, AIDS Res. Hum. Retroviruses 5:337-343, 1989). To determine the genetic identity of the viruses infecting these animals, we used PCR to examine SIV sequences directly in uncultured leukocyte DNA. Targeting two different, nonoverlapping genomic regions, we amplified and sequenced a 673-bp gag gene fragment and a 908-bp env gene fragment from one of the two baboons. Phylo-genetic analyses revealed that this baboon was infected with an SIVAGM strain of the vervet subtype. These results provide the first direct evidence for simian-to-simian cross-species transmission of SIV in the wild.

The pseudodisaccharides: a novel class of group I intron splicing inhibitors

Lysinomicin, a naturally-occurring pseudodisaccharide, inhibits translation in prokaryotes. We report that lysinomicin (and three related compounds) are able to inhibit the self-splicing of group I introns, thus identifying pseudodisaccharides as a novel class of group I intron splicing inhibitors. Lysinomicin inhibited the self-splicing of the sunY intron of phage T4 with a Ki of 8.5 microM (+/- 5 microM) and was active against other group I introns. Inhibition was found to be competitive with the substrate guanosine, unlike aminoglycoside antibiotics, which act non-competitively to inhibit the splicing of group I introns. Competitive inhibitors of group I intron splicing known to date all contain a guanidino group that was thought to be required for inhibition; lysinomicin lacks a guanidino group.

Enhanced aggregation and beta structure of amyloid beta peptide after coincubation with C1q

Several lines of evidence now suggest that aggregation of soluble amyloid beta peptide (A beta) into a cross beta sheet configuration may be an important factor in mediating potential neurotoxicity of A beta. Synthetic A beta has been shown to self aggregate in vitro. Here, we demonstrate that coincubation of freshly solubilized A beta with C1q, a complement component known to bind A beta in vitro and to colocalize with A beta in vivo, results in as much as a 7-fold enhancement of A beta aggregation, as well as a 2-4-fold enhancement of beta structure within aggregates. The addition of C1q to preformed A beta aggregates also results in significantly increased resistance to aggregate resolubilization.

Use of daily Acute Physiology and Chronic Health Evaluation (APACHE) II scores to predict individual patient survival rate

OBJECTIVE

To evaluate the use of daily Acute Physiology and Chronic Health Evaluation (APACHE) II scoring in the prediction of individual mortality rates for intensive care unit (ICU) patients.

DESIGN

A prospective study of consecutive patients admitted to four university-affiliated ICUs.

SETTING

Medical-surgical ICUs of four tertiary care academic hospitals.

PATIENTS

Daily data from 3,350 consecutive ICU admissions, excluding postoperative cardiac patients, were collected from January to December 1991.

MEASUREMENTS AND MAIN RESULTS

Daily APACHE II scores were calculated for all patients and correlated with both ICU and hospital mortality. The ability of an absolute level or a predetermined algorithm, based on these scores, to predict mortality was examined. Day 1 APACHE II scores ranged from 0 to 55 (mean 18). We were unable to replicate the suggestion by Chang et al. that 100% hospital mortality was predicted by the following APACHE II scores: a) > 35 at admission; b) 30 to 35 at admission, with a decrease of < or = 3 from day 1 to day 2; or c) > 27 on any day, with an increase of > 2 from the previous day. We were unable to adjust these criteria to avoid a false prediction of death with any remaining useful sensitivity. Mortality rates of 158 (69%) deaths per 229 patients, 68 (62%) deaths per 110 patients, and 110 (48%) deaths per 230 patients were obtained, respectively, for these criteria.

CONCLUSIONS

Admission or daily APACHE II scores do not predict individual patient mortality. The adjustments needed in the algorithm that was used to avoid a false prediction of death render sensitivity so low that it would be impractical to limit therapy on this basis alone.

Atlanto-occipital joint pain. A report of three cases and description of an intraarticular joint block technique

BACKGROUND AND OBJECTIVES

The atlanto-occipital (AO) joint is a true, innervated synovial joint with the potential to cause pain.

METHODS

A detailed description of an AO joint injection technique is provided, as none was found on review of the literature.

RESULTS

Using this technique, three illustrative cases provide preliminary evidence that intraarticular injection of the AO joint may have both diagnostic and therapeutic value for the treatment of upper cervical pain and headaches.

CONCLUSIONS

Although AO joint injections may prove to be an effective adjunct to more traditional forms of conservative treatment, additional prospective studies are needed to better define the role of intraarticular AO joint injections in the diagnosis and treatment of head and neck pain.