Karyological identification of two taxa of the Anopheles balabacensis complex from Burma

Giemsa and Hoechst staining of neuroblast chromosomes were used to identify two strains of the Anopheles balabacensis complex from Burma. The laboratory colony of Kwan-ka-thaung (KKT) strain is shown to correspond to A. dirus A, while the laboratory colony of Taikkyi (TKK) strain corresponds to A. dirus C as defined by earlier studies on material from Thailand.     

Estimation of survival rate and oviposition interval of Anopheles balabacensis mosquitoes from mark-recapture experiments in Sabah, Malaysia

An exophilic population of the vector mosquito Anopheles balabacensis Baisas was investigated in two mark-recapture studies (16.ix-13.x.1986 and 6-26.i.1987) at an inland, foothill village in Sabah, Malaysia. Wild female mosquitoes were intercepted as they came to feed on man or buffalo, given a bloodmeal, marked with fluorescent dust and released. The recapture rate was about 12%. A new method of analysis is proposed which uses cross-correlation and a time series model. The estimated survival per oviposition cycle was 0.48-0.54 and the oviposition cycle interval 2-3 days.     

Pain pathways and transmission.

Pain has been a major concern of humankind since the ancient times, and it remains one of the most important subjects of all health care professionals. Despite the obvious overwhelming clinical importance, the major advances in its diagnosis and therapy have been made only recently. "How do the sensory apparatus of the body and system of signal transmission relate to pain of peripheral origin?" is the topic of discussion. To do this, it is important to understand what constitutes the total pain experience. It consists of: 1) signal transduction at the peripheral receptor site, 2) signal conduction along the peripheral nerve, 3) pain modulation at the level of the spinal cord, 4) pain perception at the supraspinal site, and 5) the associated sensations, emotional reactions, and effective state. The signal transmission related to pain may be modified by various analgesic agents. Specific analgesic agent has a specific site of action which may be at peripheral receptors, at peripheral nerves, at the level of the spinal cord, at supraspinal levels by activating descending inhibitory systems, or at more cephalad levels by reducing the affective component of pain.     

Studies on the transmission of simian malaria. VI. Mosquito infection and sporozoite transmission of Plasmodium fragile.

Anopheles b. balabacensis mosquitoes were infected with Plasmodium fragile when fed upon splenectomized Macaca mulatta monkeys. Highest level mosquito infections were obtained when feedings were made from 2 to 4 days prior to the peak in the parasitemia. Transmission to M. mulatta monkeys was obtained via mosquito bite on 2 occasions and via intrahepatic and intravenous inoculation of dissected infected salivary glands on 9 occasions. The prepatent periods ranged from 12 to 17 days with a median of 15 days.     

Emission and transmission brain tomography.

Comparative emission and transmission brain tomograms were obtained in 209 patients to establish the diagnostic accuracy of a new emission tomographic scanner in detecting space-occupying disease in the brain. Concordant results were obtained in 169 patients (81%). Computed transmission tomography (transmission CT) yielded an overall rate of false-positive results of 0.48% and a false-negative rate of 6%. Emission CT yielded a false-positive rate of 0% and false-negative rates of 2.4% for malignant disease and 10% for vascular disease. The higher rate of false-negative results for vascular disease with emission CT occurs because transmission CT can detect old infarction. The rates of detection of recent vascular disease with emission and trnasmission CT are identical. Thus emission CT is highly sensitive in detecting space-occupying disease in the brain. It represents an ideal screening procedure.     

Cyclic nucleotides and neuromuscular transmission.

A review of the research on cyclic nucleotides and neuromuscular transmission suggests that cAMP is involved in the release of transmitter from motor nerve endings. Lipid-soluble derivations of cAMP cause depolarization of unstimulated nerve endings and prolong the after potentials of stimulated nerve endings. They also increase the frequency of miniature end plate potentials and increase the quantal content of stimulus evoked end plate potentials. Similar effects are produced by compounds that activate adenylate cyclase or inhibit phosphodiesterase. The responses to the derivatives of cAMP and activators of cyclase are enhanced by inhibitors of phosphodiesterase and prevented by compounds that block the flux of calcium into nerve endings. There is no evidence that suggests that cyclic nucleotides are involved in the postjunctional response to transmitter. Thus, it seems likely that cAMP is involved in the regulation of calcium in motor nerve endings and the exocytosis of transmitter. Additional study should expand our knowledge of neuromuscular transmission and contribute to an understanding of the functions of cyclic nucleotides in other synapses.     

Horizontal transmission of murine retroviruses.

Both a feral mouse ecotropic virus (WM-E) and Friend ecotropic virus (F-MuLV) were transmitted horizontally among adult mice. Infection resulted in the production of antiviral antibody in the recipients, with no evidence of viremia or clinical disease. However, persistent low-level virus replication was detectable in the spleens of these mice as long as 8 months after initial infection. External secretions, including saliva, semen, and uterine secretions from viremic mice contained high concentrations of infectious virus. Nevertheless, transmission occurred only from viremic males to either males or females. Male-to-male transmission appeared to occur by parenteral inoculation of infectious saliva during fighting behavior. Evidence is presented that infection of females was by the venereal route. Of four mouse strains examined, NFS/N, IRW, and C57L females were all susceptible to venereal infection, whereas AKR mice were not. Since AKR mice are susceptible to infection by WM-E administered parenterally, this resistance appeared to be mediated by local viral interference due to the high-level expression of endogenous Akv gp70 within the female reproductive tract. Although both WM-E and F-MuLV were transmitted from viremic males to females, infection by WM-E was significantly more efficient than that by F-MuLV. This difference correlated with a distinct difference in cellular tropism of WM-E and F-MuLV within the epididymis of viremic males. F-MuLV gp70 was expressed only within stromal elements, whereas WM-E gp70 was seen largely within the epithelial lining cells and luminal contents of the duct. No evidence of virus expression within germ cells was observed. The possible influence of virus expression by epithelial cells of the female reproductive tract on infection of embryos is discussed.     

Placental transmission of thyroid-stimulating immunoglobulins.

Long-acting thyroid stimulator (LATS) and LATS protector (LATS-P) were assayed at or near delivery in serum from 18 pregnant women with a history of past or present thyrotoxicosis. The results suggested that neonatal thyrotoxicosis may be predicted prenatally if maternal serum LATS and LATS-P concentrations near delivery are above certain levels.     

Long-range air transmission of bacteria.

Bacterial spores from a sandstorm area north of the Black Sea were transmitted to Sweden by air, giving increased concentrations of viable bacterial spores at two air sampling stations in Sweden.