Seasonal abundance of Anopheles farauti (Diptera: Culicidae) sibling species in far north Queensland, Australia

In the Cairns area of far north Queensland, Australia, the seasonal abundance of Anopheles farauti Laveran sibling species was studied at 6 locations, representing 3 habitat types, between August 1995 and September 1997. A total of 45,401 An. farauti s.l. was collected using CO2 + octenol baited CDC light traps, and consisted of 29,565 An. farauti No. 2, 14,214 An. farauti No. 3, and 1,622 An. farauti s.s. The relative abundance of all 3 species differed significantly by season and location. An. farauti No.2 was the dominant species except in Cairns, where An. farauti s.s. was most abundant, and at Ninds Creek, where An. farauti No. 3 predominated. The dominant species at each location was present year round, although peaks in seasonal abundance were observed. An. farauti s.s. populations were highest during the wet season (January-April). In lowland freshwater swamp habitats and 1 brackish location, An. farauti No. 2 was more abundant during the wet season. However, at the highland freshwater swamp habitat, populations of An. farauti No. 2 were highest during the late dry season and early wet season (October-December). There was a significant positive correlation of both temperature and rainfall with An. farauti s.s. and An. farauti No. 2 trap collections. There was a negative correlation between An. farauti No. 3 and temperature, indicating that this species may be more abundant during cool weather. Although there were significant relationships among weather variables and An. farauti s.l. collections, correlation values were generally low, indicating that other factors may contribute to variability among An. farauti sibling species trap collections.     

Influence of zinc on Pseudomonas aeruginosa susceptibilities to imipenem.

Serial dilution susceptibility testing of imipenem against 59 clinical isolates of Pseudomonas aeruginosa, conducted simultaneously on single lots of Difco and BBL Mueller-Hinton agar (MHA), resulted in MICs for 90% of strains tested of 8 and 16 micrograms/ml, respectively. MICs for Escherichia coli, Klebsiella pneumoniae, and Pseudomonas spp. were also higher on BBL MHA. Quantification of the cation content of the two MHAs by atomic absorption spectroscopy demonstrated that the zinc concentration in BBL MHA was 15 times greater than that measured in Difco MHA (2.61 and 0.17 micrograms/ml, respectively). Concentrations of calcium, magnesium, iron, manganese, and copper in the two agars were similar. Addition of zinc to Difco MHA resulted in increases in MICs of imipenem for P. aeruginosa but not in the MICs of ceftazidime or cefpirome for P. aeruginosa (P < 0.01). A lesser zinc effect was seen on the activity of imipenem against E. coli, K. pneumoniae, and Pseudomonas spp. The activities of ceftazidime and cefpirome were similar on both MHAs when tested against all gram-negative organisms in this study. Thus, the effect of zinc in MHA was clearly demonstrated by a significant increase in the MICs of imipenem for P. aeruginosa, and, to a lesser extent, for other gram-negative bacilli.     

Development of fever in the newborn lamb.

Newborn lambs do not become febrile in response to intravenous (iv) bacterial endotoxin in moderate doses. Newborn lambs were tested to see if they could become febrile to large doses of endotoxin or to endogenous pyrogen. At 5 h of age lambs do not become febrile to relatively large doses of endotoxin or to endogenous pyrogen, but rather become hypothermic. At 32 h and all subsequent times, fevers could be elicited. Onset time of fevers in lambs was short initially and gradually lengthened over 9 days, at which time it was similar to the onset time of the adult fever. With respect to the febrile response, newborn lambs showed varying degrees of tolerance after 10 days of daily injections of endotoxin, as compared to the ewe which becomes tolerant in 2 or 3 days.     

Values and ethics: a collection of curricular reforms for a new generation of physicians.

In recent years, medical educators have expressed concern that the reductionist-positivist mode of medical education fails to equip physicians with the skills and attitudes to meet the full range of patients' physical and emotional needs. Indeed, the authors suggest that neither patients nor physicians are satisfied. Among the factors responsible are a pervasive industrialization of clinical practice, a progressive segmentation of patient care, and a deepening shortage of both primary care and specialty physicians. But underlying these system issues is a lack of adequate schooling in the values, ethics, and culture of caring. Today's physicians must simultaneously be analytical, perceptive, and self-reflective. They must have the capacity to see their patients as individuals with differing psychological, social, and historical natures. And they must have insight into their own values and behaviors. All of this contributes to making a competent and humane physician. To aid medical students in achieving these characteristics, the authors contend that medical education must be radically restructured so that knowledge and skills are taught within the context of values and ethics. This commentary explores such reform through the lens of three articles published in the current issue of Academic Medicine, by Litzelman and Cottingham, Kanter and colleagues, and Dobie. These articles are the product of a national call that resulted in more than thirty abstracts, testimony to the fertile thinking already being applied to this problem. It is the authors' hope that this series of papers will stimulate still more thinking and lead to the curricular reform that future generations of physicians deserve.     

Development and Evaluation of a PCR-Based Assay for Detection of Haemobartonella felis in Cats and Differentiation of H. felis from Related Bacteria by Restriction Fragment Length Polymorphism Analysis

The 16S rRNA gene of Haemobartonella felis was amplified by using universal eubacterial primers and was subsequently cloned and sequenced. Based on this sequence data, we designed a set of H. felis-specific primers. These primers selectively amplified a 1,316-bp DNA fragment of the 16S rRNA gene of H. felis from each of four experimentally infected cats at peak parasitemia. No PCR product was amplified from purified DNA of Eperythrozoon suis, Mycoplasma genitalium, and Bartonella bacilliformis. Blood from the experimental cats prior to infection was negative for PCR products and was greatly diminished or absent 1 month after doxycycline treatment. The overall sequence identity of this fragment varied by less than 1.0% among experimentally infected cats. By taking into consideration the secondary structure of the 16S rRNA molecule, we were able to further verify the alignment of nucleotides and quality of our sequence data. In this PCR assay, the minimum detectable number of H. felis organisms was determined to be between 50 and 704. The potential usefulness of restriction enzymes DdeI and MnlI for distinguishing H. felis from closely related bacteria was examined. This is the first report of the utility of PCR-facilitated diagnosis and discrimination of H. felis infection in cats.     

Genomic structure of PIR-B, the inhibitory member of the paired immunoglobulin-like receptor genes in mice

Abstract: The genes encoding the murine paired immunoglobulin-like receptors PIR-A and PIR-B are members of a novel gene family which encode cell-surface receptors bearing immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and their non-inhibitory/activatory counterparts. PIR-A and PIR-B have highly homologous extracellular domains but distinct trans-membrane and cytoplasmic regions. A charged arginine in the transmembrane region of PIR-A suggests its potential association with other transmembrane proteins to form a signal transducing unit. PIR-B, in contrast, has an uncharged transmembrane region and several ITIMs in its cytoplasmic tail. These characteristics suggest that PIR-A and PIR-B which are coordinately expressed by B cells and myeloid cells, serve counter-regulatory roles in humoral and inflammatory responses. In the present study we have determined the genomic structure of the single copy PIR-B gene. The gene consists of 15 exons and spans approximately 8 kilobases. The first exon contains the 5' untranslated region, the ATG translation start site, and approximately half of the leader peptide sequence. The remainder of the leader peptide sequence is encoded by exon 2. Exons 3–8 encode the six extracellular immunoglobulin-like domains and exons 9 and 10 code for the extracellular membrane proximal and transmembrane regions. The final five exons (exons 11–15) encode for the ITIM-bearing cytoplasmic tail and the 3' untranslated region. The intron/exon boundaries of PIR-B obey the GT-AG rule and are in phase I, with the notable exception of the three boundaries determined for ITIM-containing exons. A microsatellite composed of the trinucleotide repeat AAG in the intron between exons 9 and 10 provides a useful marker for studying population genetics.     

Benefit of nasal CPAP in obstructive sleep apnea is due to positive pharyngeal pressure

The purpose of this study was to determine if the mechanism of nasal continuous positive airway pressure's (CPAP's) effectiveness is to act as a pneumatic splint or to increase functional residual capacity (FRC) and consequently, upper airway caliber. Four subjects with obstructive sleep apnea underwent 3 nights of polysomnography: night 1, control; night 2, nasal CPAP; night 3, external subatmospheric pressure (ESAP). ESAP, a negative pressure body suit, increases FRC. We measured the changes in FRC with nasal CPAP and ESAP using the weighted spirometer technique. The dose used for the ESAP night was the dose that produced the same FRC as the subject's prescribed nasal CPAP dose. The mean number of arousals and the respiratory events index were higher on ESAP and control nights. Less severe oxygen desaturation occurred during non-rapid-eye-movement sleep on the nasal CPAP and ESAP nights. These preliminary results show that increasing FRC alone does not account for the effectiveness of nasal CPAP, and splinting of the collapsible upper airway is necessary.     

Homozygosity for autosomal dominant Marfan syndrome.

Marfan syndrome is an autosomal dominant condition with varying phenotypic manifestations. Affected persons are usually heterozygotes. A family is presented in which the gene for this syndrome is segregating in a large number of members. Two sibs suffered from unusually severe, identical, and fatal manifestations from birth, their parents having mild cardiovascular and somatic symptoms common in Marfan syndrome. Investigation of collagen biosynthesis in fibroblasts revealed no abnormalities in fibronectin and procollagen I and III synthesis and secretion or in the procollagen to collagen conversion. We suggest that these two sibs are examples of homozygosity for the Marfan syndrome gene, based on the large number of affected members, the absence of additional consanguinity, manifestation of the syndrome in both parents, and the severity of the disease in the two sibs.     

Visceral pleural invasion in lung cancer: recognizing histologic parameters that impact staging and prognosis

Visceral pleural involvement (VPI) is a critical component in the staging of non-small cell lung carcinoma (NSCLC). Tumors < or =3 cm that involve the visceral pleura are classified as T2 lesions, underscoring the prognostic significance of this histologic parameter. Accurate staging of small NSCLCs depends on appropriately assessing the presence or absence of VPI. Elastic stains can be instrumental in detecting disruptions of the visceral pleural elastic layer by tumor, a finding that has prognostic and staging implications similar to tumor that is present on the visceral pleural surface.