Plague Meningitis—A Retrospective Analysis of Cases Reported in the United States, 1970-1979

Meningitis caused by Yersinia pestis developed in 6 (6%) of a total of 105 patients with plague reported to the Centers for Disease Control from 1970 to 1979. Five of the six cases occurred in children aged 10 to 15 years. All six patients received antibiotic therapy before meningitis developed, which appeared between the 9th and 14th days after the onset of acute illness in five of the six patients. There were no neurologic sequelae. The antigenic and biochemical profiles of the Y pestis strains isolated from cerebrospinal fluid in the meningitis cases did not differ from those of the Y pestis strains obtained from blood and bubo aspirates in the other 99 patients, and neither did in vitro studies suggest antibiotic resistance. While plague meningitis is an uncommon complication of acute plague infection, physicians in the western United States should be aware that it may develop as much as 14 days after antibiotic therapy for the acute plague infection has been initiated.     

Global Epidemiology

A total of 62,811 cases of the acquired immunodeficiency syndrome (AIDS) have been reported to the World Health Organization from throughout the world. Extensive epidemiologic studies have shown that human immunodeficiency virus (HIV) infections are transmitted by three routes: sexual, parenteral and perinatal. Three geographic patterns of transmission have been defined. In pattern I, transmission occurs predominantly among homosexual and bisexual men and urban intravenous drug abusers; transmission via blood products has been controlled; the male:female sex ratio is 10:1 or more; population HIV seroprevalence is low, and perinatal transmission is uncommon (for instance, United States, western Europe). In pattern II, transmission is predominantly heterosexual and perinatal; transmission via blood products exists but is being reduced; unsterile needles and other skin-piercing instruments cause some parenteral transmission (magnitude not known); the male:female sex ratio is 1:1, and population seroprevalence often exceeds 1% (central Africa, Haiti). In pattern III, AIDS cases are just being documented and are generally due to sexual exposure abroad or imported blood products (Middle East, Asia).     

Emerging Patterns of HIV Infection and Control in the Philippines

A total of 50 carriers of the human immunodeficiency virus (HIV), 46 of them female prostitutes, have been detected through seroprevalence surveys by the Department of Health, Manila. Infection rates are highest in two small cities near foreign military bases and in the tourist district of MetroManila. Nine patients with the acquired immunodeficiency syndrome (AIDS) who contracted the disease outside the country have been reported, with opportunistic infections being the major clinical feature. Public information measures heavily utilize the mass media, and there is anecdotal evidence that awareness of the disease among the urban population is increasing. The National AIDS Committee foresees that a large proportion of the cases seen in the Philippines over the next few years will be returning nationals who were infected abroad.     

Optimizing the expression of chimeric genes in plant cells

Summary The Serratia marcescens chiA gene encodes a secreted chitinase activity which contributes to the fungal growth inhibition exhibited by this bacterium. The coding region from the chiA gene was fused to the promoter and 3 polyadenylation region of the Agrobacterium nopaline synthase gene. Site-directed mutagenesis of specific nucleotides surrounding the initiating AUG of the coding sequence of this chimeric gene resulted in up to an eight-fold increase in the amount of chitinase protein detected in transformed plant tissue. Analysis of the chiA mRNA indicated that these nucleotides also affected mRNA levels. At least 50% of the chitinase protein produced in transformed tobacco cells was the same molecular weight as the S. marcescen secreted protein.     

Evolution of the Ribosomal DNA Spacers of Drosophila melanogaster : Different Patterns of Variation on X and Y Chromosomes

Length variation of the ribosomal gene spacers of Drosophila melanogaster was studied. Analysis of 47 X chromosomal and 47 Y chromosomal linked rDNA arrays collected from five continents indicates that the arrays on the two chromosomes differ qualitatively. The Y-linked arrays from around the world share little or no similarity for either their overall length or the organization of their spacers. Most of the X-linked arrays do, however, share a major length spacer of 5.1 kb. In addition, those X-linked arrays that have a major 5.1-kb band have similar spacer organization as demonstrated by genomic DNA digestions with several restriction enzymes. These data strongly support the hypothesis that spacer length patterns on only X-linked genes are maintained primarily by natural selection.     

Demographic Trends of Aging — Application to Gerodontology1

Aging of the global world population both in developed and developing countries, an unbalanced male-female ratio within this elderly population, increasing populations – including elderly – within urban areas, all will have a marked effect on the practice of dentistry. Furthermore, major epidemiological changes occurring in the dental field, including an increasing dentition life expectancy, increasing root caries prevalence, decreasing coronal caries rates in children, and the relative increase in the prevalence of periodontal problems will have further impact on the dental care system. Major changes need to be anticipated both at the level of the care provider, including the dentist, the hygienist and the dental assistant, and at the level of the potential patient, especially among the geriatric population, if the profession is to be prepared to adequately address these issues.     

The cell biology of Drosophila wing metamorphosis in vitro

Summary We have examined the metamorphosis of the wing imaginal disc of Drosophila during culture in vitro in the continuous presence of 20-hydroxy ecdysone (0.1 g/ ml). We find that the sequence of cellular changes in the wing blade during culture closely match those occurring in situ, involving two periods at which the dorsal and ventral surfaces are joined only by cell processes containing trans-alar microtubule arrays. Good pupal and imaginal cuticle secretion is found in this system.     

Electron donation in Photosystem II

The electron transfer resulting from illumination and dark storage of PS II has been studied using EPR signals from several electron carriers. The recombination of D⁺ (Signal II) and Q⁻_A formed by illumination occurred during dark storage at 77 K and was used to deplete reaction centres of D⁺. The donor D was then shown to be oxidized in the dark by the S₂ state of the oxygen-evolving complex. A slow change which occurred during dark storage of PS II samples was detected using the power saturation characteristics of D. We interpret this effect on D to be an indirect result of a rearrangement of the manganese complex during long-term dark adaptation. A role for D in the stability, protection and perhaps initial manganese binding of the oxygen-evolving complex is suggested.     

Facultative parthenogenesis and sex-ratio evolution

Summary Phenotypic models of selection are used to determine the effect of facultative parthenogenesis on the production of males in a spatially variable environment when (i) sex determination is under strict genetic control, and (ii) when sex may be environmentally determined. The results show that when sex is under strict genetic control and there is some chance of maturing in isolation, selection favors a female-biased sex ratio. When sex can be environmentally induced by cues which indicate high density, selection favors a mixture of genetic and environmental control, such that half the individuals always become female and the other half become females when isolated and become males when not isolated.