Comparison of human and southern sea otter (Enhydra lutris nereis) health risks for infection with protozoa in nearshore waters

Cryptosporidium and Giardia spp. are waterborne, fecally-transmitted pathogens that cause economic loss due to gastroenteritis and beach closures. We applied quantitative microbial risk assessment (QMRA) to determine the health risks for humans and sea otters due to waterborne exposure of Cryptosporidium and Giardia spp. when swimming in three types of surface waters: river, stormwater and wastewater effluent during the wet and dry seasons in the central coast of California. This is the first application of QMRA to estimate both the probability of infection in Southern sea otters and the probability of illness in humans, using microbial source tracking (MST) as a variable. Children swimming close to stormwater discharges had an estimated Cryptosporidium-associated illness probability that exceeded the accepted U.S. EPA criteria (32 illnesses/1000 swimmers or 3.2%). Based on the assumption that sea otters are as susceptible as humans to Cryptosporidium infection, the infection probabilities were close to 2% and 16% when sea otters were swimming at the end of points of rivers and stormwater discharges, respectively. In the case of Giardia, infection probabilities of 11% and 23% were estimated for sea otters swimming at the end of point of wastewater discharges, assuming that sea otters are as susceptible as gerbils and humans, respectively. The results of this QMRA suggest that 1) humans and sea otters are at risk when swimming at outflow sites for rivers, stormwater and treated wastewater effluent; 2) reduced loads of viable protozoan cysts and oocysts in recreational water can lessen the probability of infection of humans and sea otters; and 3) the risk of infection of humans and sea otters can be reduced with the treatment of wastewater to decrease oocyst and cyst viability before effluent is released into the sea.

Micro-engineered remote palpation device for assessing tissue compliance

This paper concerns the operation of the actuator for a prototype micro-engineered mechanical palpation device for deployment via a cystoscope to measure the dynamic mechanical properties of the prostate gland in vivo. The subassembly consists of a 400x200 microm silicon (Si) piston manufactured using deep reactive ion etching (DRIE) housed within an anodically bonded glass-Si-glass sandwiched housing. The micro-channel on the Si layer was formed by powder blasting and contains the micro-piston with one end pointing to the side of the housing and the other facing a via hole leading to a capillary tube. The opening on the side of the housing was sealed by a 5 microm thick silicone membrane which acts to retain the micro-piston and act as a return spring. A 320 microm diameter capillary forms the connection between the micro-channel and a micro-syringe which is operated by a programmable syringe pump to produce a reciprocating action. A pressure sensor is connected along the capillary tube to measure the dynamic pressure within the system. The micro-piston has already been used, separately actuated to measure the dynamic mechanical properties of known viscoelastic materials and prostate tissue. The purpose of the present work is to assess the functionality of the actuator assembly.

Sudden infant death syndrome in Indigenous and non-Indigenous infants in north Queensland, 1990-1998

OBJECTIVE

To compare the epidemiology of sudden infant death syndrome (SIDS) in Indigenous and non-Indigenous infants in north Queensland, and to assess the quality of data recorded for SIDS deaths.

METHODS

Records were obtained for SIDS cases from all coronial courts in north Queensland from 1990 to 1998. Demographic characteristics, ethnicity, age at death, sleeping and feeding patterns, smoking incidences and autopsy findings were compared. Incidences, medians and univariate associations were generated where appropriate.

RESULTS

There were 83 248 live births for the 9-year period; 71 389 non-Indigenous and 11 859 Indigenous births. There were 69 SIDS deaths (0.83 per 1000 live births). Overall, recording of demographic and death scene data was poor. Thirty-eight autopsies (55%) were performed by specialist pathologists. There were 22 (32%) non-Indigenous and 22 (32%) Indigenous SIDS deaths (25 ethnicity unknown), giving an estimated relative risk of 2.82 (95% CI 2, 4). Median age at death was 13.1 weeks (range 1-83 weeks) with 14% of deaths occurring in the neonatal period for both groups. Sleeping position was not recorded in 42% of cases and co-sleeping was not recorded in 27% of cases. Bed sharing was more common amongst Indigenous infants. Fifty-two per cent of SIDS cases occurred in the wet season and 48% in the dry season.

CONCLUSIONS

Data recorded for SIDS deaths in north Queensland are poor, preventing specific conclusions concerning SIDS risk factors. However, SIDS rates may be up to three-fold higher in the Indigenous population. A uniform system of post-mortem and death scene data reporting is needed urgently.

Intubating LMA guided awake fibreoptic intubation in severe maxillo-facial injury

PURPOSE

To describe control of the airway in a patient with severe maxillo-facial injury using intubating laryngeal mask guided awake fibreoptic intubation.

CLINICAL FEATURES

A 110 kg man presented with a severe facial injury due to a horse kick. Local examination showed a large transverse gaping laceration just beneath the nose, exposing the lower nasal cavities through to the posterior nasopharynx. It was planned to perform a surgical tracheostomy before surgical fixation of the maxilla and nasal bones. Considering the patient's weight, short neck and difficulty in lying flat, surgical tracheostomy under general anesthesia was considered the best option. Under topical anesthesia, an intubating laryngeal mask was introduced followed by a fibreoptic bronchscope. The endotracheal tube was threaded over the bronchoscope and airway control achieved.

CONCLUSIONS

The use of an intubating laryngeal mask avoids the need for manipulation of the head and neck and acts as a 'shield' for the fibreoptic bronchoscope from surrounding blood in patients with maxillo-facial injury. The use of the fibreoptic bronchoscope ensures intubation under vision.

Myringotomy and ventilation tube insertion: a ten-year follow-up

Eighty children who had myringotomy performed for otitis media with effusion in 1984 were reviewed in 1994. This had involved surgery on 158 ears. Three aspects of ear condition were studied: hearing loss, tympanic membrane perforation, and tympanosclerosis. Hearing losses were present in 13 ears (8.2 per cent), involving 10 children (12.5 per cent), although losses were under 20 dB in seven of these ears (five patients). Of the six ears with losses more than 20 dB (3.8 per cent), in five patients bilateral losses of 30 dB were due to a recurrence of effusions, a large dry posterior perforation was the cause of a 30 dB loss, an infected anterior perforation had caused a 30 dB loss, an ear which had a cholesteatoma, and had a mastoidectomy and ossiculoplasty in 1987, had a 30-40 dB loss, and one ear which had a Type 1 tympanoplasty in 1994 had a 50 dB loss. Therefore in only three ears (1.9 per cent) could hearing loss be associated directly with myringotomy and ventilation tube insertion. Perforations had persisted unilaterally in seven patients, three having had tympanoplasties. Of the remaining perforated tympanic membranes, two were free of symptoms, one had only a slight hearing loss, and one had a more significant loss with recurrent infection. Tympanosclerosis was only found in those ears which had ventilation tubes inserted (and not those which had myringotomy only), occurring in 48 ears (31 per cent, of 39 per cent of those which had a ventilation tube inserted). There was no link between tympanosclerosis and hearing loss. The site of tympanosclerosis was not restricted to the site of myringotomy, and in many cases was present only in other areas of the tympanic membrane. There was a tendency for more extensive tympanosclerosis to occur in those ears which had more ventilation tube insertions. The risk of perforation in particular lends support to a policy of 'watchful waiting'.

Exon switching and activation of stromal and embryonic fibroblast growth factor (FGF)-FGF receptor genes in prostate epithelial cells accompany stromal independence and malignancy

Stroma and the heparin-binding fibroblast growth factor (FGF) family influence normal epithelial cell growth and differentiation in embryonic and adult tissues. The role of stromal cells and the expression of isoforms of the FGF ligand and receptor family were examined during malignant progression of epithelial cells from a differentiated, slowly growing, nonmalignant model rat prostate tumor. In syngeneic hosts, a mixture of stromal and epithelial cells resulted in nonmalignant tumors which were differentiated and slowly growing. In the absence of the stromal cells, epithelial cells progressed to malignant tumors which were independent of the stroma and undifferentiated. The independence of the malignant epithelial cells from stromal cells was accompanied by a switch from exclusive expression of exon IIIb to exclusive expression of exon IIIc in the FGF receptor 2 (FGF-R2) gene. The FGF-R2(IIIb) isoform displays high affinity for stromal cell-derived FGF-7, whereas the FGF-R2(IIIc) isoform does not recognize FGF-7 but has high affinity for the FGF-2 member of the FGF ligand family. The switch from expression of exclusively exon IIIb to exclusively exon IIIc in the resident FGF-R2 gene was followed by activation of the FGF-2 ligand gene, the normally stromal cell FGF-R1 gene, and embryonic FGF-3 and FGF-5 ligand genes in malignant epithelial cells. Multiple autocrine and potentially intracrine ligand-receptor loops resulting from these alterations within the FGF-FGF-R family may underlie the autonomy of malignant tumor cells.

Exon skipping causes alteration of the COOH-terminus and deletion of the phospholipase C gamma 1 interaction site in the FGF receptor 2 kinase in normal prostate epithelial cells

Polymerase chain reaction analysis revealed an mRNA in rat prostate that results from alternate splicing of exon 16 in the heparin-binding fibroblast growth factor receptor kinase type 2 gene (FGFR2). The absence of exon 16 and the shift in reading frame at the exon 15-17 junction predicts an expression product (FGFR2-2) with a unique COOH-terminus that does not exhibit the major autophosphorylation site (tyrosine 789) required for interaction of phospholipase C gamma 1 with the full-length FGFR2-1 isoform. Nuclease protection analysis revealed that the FGFR-2 splice variant is expressed in quantities equal to or greater than the FGFR2-1 isoform in normal prostate tissue. When combined with the same FGFR2 extracellular domain, co-expression of the two COOH-terminal variants may mediate effect of the same FGF ligand on different signal transduction pathways.

Substitution of putative half-cystine residues in heparin-binding fibroblast growth factor receptors. Loss of binding activity in both two and three loop isoforms

Alternate use of an exon coding for an 89-residue NH2 terminal immunoglobulin-like disulfide loop results in isoforms of the heparin-binding fibroblast growth factor receptor (FGF-R) with three (FGF-R alpha) and two (FGF-R beta) Ig-like loops in the extracellular domain. Both FGF-R alpha and FGF-R beta isoforms exhibit qualitatively similar ligand-binding activities. In this report, we show by site-directed mutagenesis and analysis of ligand-binding activity in transfected cells that substitution of a cysteine that potentially forms an intra-loop disulfide in either juxtamembrane Loop II or III disrupted maturation and formation of the ligand-binding site in both FGF-R alpha and FGF-R beta isoforms. Neither three loop FGF-R alpha constructions coding for intact Loops I and II adjacent to defective Loop III nor intact Loops I and III separated by defective Loop II exhibited ligand-binding activity. In addition, a two-loop molecule of tandem Loops I and III was inactive. The results suggest that single Loops I, II, or III of FGF-R are insufficient to form a ligand-binding site. Loop I does not form an independent ligand-binding site with either Loop II or III, but interacts with a common ligand-binding site formed by Loops II and III (Xu, J., Nakahara, M., Crabb, J. W., Shi, E., Matuo, Y., Fraser, M., Kan, M., Hou, J., and McKeehan, W. L. (1992) J. Biol. Chem. 267, 17792-17803, 1992).

Vaccines for HIV infected pregnant women?

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Hypothyroidism due to destruction of the thyroid by Kaposi's sarcoma

A case of hypothyroidism that manifested as depression and deteriorating functional status and that ultimately resulted in the death of a 41-year-old patient with AIDS is described. Postmortem examination revealed destruction of the thyroid gland by Kaposi's sarcoma. Analysis of stored serum samples revealed that the patient had become profoundly hypothyroid during his terminal illness. Practitioners are reminded of the need to exclude metabolic causes when treating encephalopathy in patients infected with human immunodeficiency virus.

Fibroblast growth factor receptors from liver vary in three structural domains

Changes in heparin-binding fibroblast growth factor gene expression and receptor phenotype occur during liver regeneration and in hepatoma cells. The nucleotide sequence of complementary DNA predicts that three amino-terminal domain motifs, two juxtamembrane motifs, and two intracellular carboxyl-terminal domain motifs combine to form a minimum of 6 and potentially 12 homologous polypeptides that constitute the growth factor receptor family in a single human liver cell population. Amino-terminal variants consisted of two transmembrane molecules that contained three and two immunoglobulin-like disulfide loops, as well as a potential intracellular form of the receptor. The two intracellular juxtamembrane motifs differed in a potential serine-threonine kinase phosphorylation site. One carboxyl-terminal motif was a putative tyrosine kinase that contained potential tyrosine phosphorylation sites. The second carboxyl-terminal motif was probably not a tyrosine kinase and did not exhibit the same candidate carboxyl-terminal tyrosine phosphorylation sites.

Isolation and partial characterization of a corynebacteriophage beta, tox operator constitutive-like mutant lysogen of Corynebacterium diphtheriae

We have isolated and partially characterized a beta-phage mutant lysogen of Corynebacterium diphtheriae, C7(betatoxct1+), which is partially insensitive to iron inhibition of diphtheria toxin production. tox expression by C7(betatoxct1+) was found to be partially constitutive. In the presence of concentrations of iron that almost completely inhibit the expression of diphtheria toxin by the wild type, C7(beta), the level of toxin production by C7(betatoxct1+) was found to be at least 25 times that of the parent. The purified tox gene product of C7(betatoxct1+) was immunologically and electrophoretically identical to, and equally as toxic as, diphtheria toxin purified from C7(beta). In addition, the partial N-terminal amino acid sequence was found to be identical to diphtheria toxin. This data strongly suggests that the mutation allowing for the constitutive expression of tox in C7(betatoxct1+) is outside of the structural gene. Furthermore, the constitutive expression of diphtheria toxin was found to be cis dominant in the double lysogen C7(betacrm45+/betatoxct1+). The data presented is consistent with the existence of a tox operator locus.

The isolation syndrome in childhood

A new diagnostic category--the Isolation Syndrome--is proposed to describe a pattern of abnormal behaviour in children. The child's 'isolated' state manifests itself in defective social interaction and communication between mother and child, in disorders of perceptual function and motor skills, in stereotyped behaviour and in general developmental retardation, especially in language. The typical situations in which the syndrome is likely to occur are discussed, and methods of treatment, both prophylactic and remedial, are given in detail. The purpose of identifying the Isolation Syndrome is to alert clinicians to the possibility that in some children with abnormal patterns of behaviour there is a specific and treatable difficulty in the child's environment.