Monoclonal antibody production in ascites fluid

Summary Hybridoma cell lines grown as ascites tumors in pristane primed mice will frequently yield milligram quantities of monoclonal antibody per milliliter of ascites fluid. Ascites production is an excellent method for the research scientist to generate high titer antibody with minimal effort. Through commercial production, gram to kilogram quantities can be achieved.     

SELECTIVE HABITUATION OF GALVANIC SKIN RESPONSE COMPONENT OF THE ORIENTATION REACTION TO AN AUDITORY STIMULUS

The prediction from Sokolov's (1960) theory that, following OR habituation, size of OR return is proportional to the amount of difference between the new stimulus and the habituating stimulus was tested using an auditory stimulus varying in frequency and intensity. Five Ss were allocated to each of 16 conditions, three conditions involving changes in frequency, three involving changes in intensity, nine involving changes in both frequency and intensity, with one control condition involving a repetition of the habituating stimulus. Following habituation of the GSR component of the OR to a criterion of response failure for three successive trials, magnitude of GSR under the 16 conditions was measured. Contrary to Sokolov's theory, only increase in intensity had a significantly different effect on OR return. More importantly, it was found that Ss habituating rapidly to the initial stimulus were less likely to show OR return to stimulus change. It was concluded that individual differences in habituation rate may be more important than stimulus difference effects in selective habituation.     

Familial testicular cancer: interest in genetic testing among high-risk family members.

PURPOSE: This study is part of an ongoing National Cancer Institute multidisciplinary, etiologically-focused, cross-sectional study of Familial Testicular Cancer (FTC). The current report targets interest in clinical genetic testing for susceptibility to FTC. METHODS: Demographics, knowledge, health beliefs, and psychological and social factors were evaluated as covariates related to interest in genetic testing. RESULTS: The majority (66%) of 229 participants (64 affected men, 66 unaffected men, and 99 women) from 47 multiple-case FTC families expressed interest in having a genetic test within 6 months, should such a test become available. Interest was similar among the three subgroups mentioned above. Worries about insurance discrimination based on genetic test results were associated with a significantly lower interest in testing. Alternatively, participants were more likely to be interested in genetic testing if they were younger and had higher levels of family support, a physician's recommendation supporting testing, cancer distress, and a need for information to inform the health care of their children. CONCLUSIONS: This study reveals social and relationship factors that FTC survivors and their relatives considered important when contemplating the use of new genetic technologies. This is the first study describing hypothetical interest in genetic testing for familial testicular cancer.     

Circovirus-infected geese studied by in situ hybridization.

It has now been established that circovirus infection is common in farmed geese, but little is known about the clinicopathological significance of such infections. Ten clinically diseased geese suspected of being infected by circovirus were studied by in situ hybridization using a goose circovirus DNA probe. Circovirus DNA was demonstrated in the bursa of Fabricius (BF), spleen, thymus, bone marrow, liver, kidney, lung and heart, indicating that infection can be multisystemic. In some birds, virus DNA was present in very large quantities, most notably in the BF, liver and small intestine. With the exception of BF and thymus, there were no histological findings that would have suggested the presence of such quantities of circovirus DNA. In view of the very large quantities of virus DNA labelling present in some tissues, and by analogy to porcine circovirus type 2 infection and psittacine beak and feather virus infections, which are known to cause severe disease, and which have similar virus distribution to that found in our geese, it seems probable that the circovirus was important in the disease manifestations shown by the infected geese.     

Acute and chronic ethanol does not affect incisional pain in neonatal rats

We have previously found that in post-natal day 7 rats withdrawal from acute and chronic ethanol (EtOH) exposure lowers mechanical thresholds during withdrawal and exacerbates spontaneous pain responses to an inflammatory injury 4 days post-withdrawal. These findings suggested alterations in somatosensory pathways following EtOH exposure during the third trimester developmental equivalent. In this study we wanted to determine whether EtOH exposure during the third trimester equivalent exacerbates mechanical allodynia and thermal hyperalgesia produced by an incisional model of post-operative pain at post-natal day 21. The extent and duration of mechanical allodynia and thermal hyperalgesia following incision was measured and found to be unaffected by prior EtOH exposure.     

Ultimate tensile strength of dentin: Evidence for a damage mechanics approach to dentin failure

Dentin structure and properties are known to vary with orientation and location. The present study explored the variation in the ultimate tensile strength (UTS) of dentin with location in the tooth. Hourglass specimens were prepared from dentin located in the center, under cusps, and in the cervical regions of human molar teeth. These were tested in tension at various distances from the pulp. Median tensile strengths ranged from 44.4 MPa in the inner dentin near the pulp, to 97.8 MPa near the dentino-enamel junction (DEJ). This increase in the median UTS with distance from the pulp to the DEJ was statistically significant (P <.001). Of particular importance was the observation that the UTS measurements followed a Weibull probability distribution, with a Weibull modulus of about 4.5. The Weibull behavior of the UTS data strongly suggests that the large variances in fracture strength data result from a distribution of preexisting defects in the dentin. These findings justify a damage-mechanics approach to studies of dentin failure.     

Vitamin A deficiency and the acute phase response among HIV-1-infected and -uninfected women in Kenya

Among HIV-1-infected individuals, vitamin A deficiency has been associated with faster disease progression and greater infectivity in observational studies, but randomized clinical trials have shown no effect of vitamin A supplementation. We conducted a cross-sectional study of 400 HIV-1-infected and 200 HIV-1-uninfected women in Mombasa, Kenya to examine the relations between vitamin A deficiency (serum retinol <30 microg/dL) and HIV-1 status, HIV-1 disease stage, and the acute phase response (serum C-reactive protein >or=10 mg/L and/or alpha1-acid glycoprotein >or=1.2 g/L). Among the HIV-1-infected women, the effect of vitamin A supplementation was examined in a randomized trial. Vitamin A deficiency was independently associated with HIV-1 infection (OR = 2.7, 95% CI: 1.9-4.0) and the acute phase response (OR = 2.8, 95% CI: 1.9-4.1). Among HIV-1-infected women, vitamin A deficiency and the acute phase response were associated with each other and were both independently associated with higher HIV-1 plasma viral load and lower CD4 count. HIV-1-infected women having an acute phase response had no increase in serum vitamin A levels after supplementation. Serum levels increased significantly among women without an acute phase response, although not to normal levels among women who were deficient at baseline. Among HIV-1-infected individuals, it is likely that low serum vitamin A concentrations reflect more active infection and the acute phase response. These results provide possible explanations for the disparity between observational studies and randomized trials of vitamin A for HIV-1 infection.     

Method for primary culture of purified leydig cells isolated from adult rat testes

Summary Preparations of 75–80% pure Leydig cells are prepared by Percoll gradient centrifugation of crude testicular interstitial cell suspensions. Using the methods described herein, the purified Leydig cells retain their functional characteristics for at least 72 hours in primary culture.     

The effect of haemorrhage on haemoglobin concentration, blood volume and arterial pressure in kittens and cats

1. The arterial haemoglobin concentration in kittens less than 24 hr old was inversely related to body weight. There was about twice as much haemoglobin/unit body weight at birth as in adult cats. Haemoglobin concentrations were minimal at 3-6 weeks of age.2. In animals lightly anaesthetized with sodium pentobarbitone, arterial pressure rose from 52 mm Hg at birth in kittens to 133 mm Hg in adult cats. Blood volume decreased from 73 ml./kg at birth to 60 ml./kg in adults.3. When kittens less than a fortnight old were subjected to stepwise blood letting, arterial pressure fell proportionately with blood volume; in older kittens and in cats, arterial pressure was less well maintained at similar proportionate reductions of blood volume than in young kittens.4. The responses to haemorrhage of kittens and cats were compared with those of rabbits similarly treated and with those of adult cats anaesthetized with urethane and chloralose reported in the literature.     

Reactions of Musca domestica L. (Diptera: Muscidae) to parasitism by Aphaereta pallipes (Say) (Hymenoptera: Braconidae), with special reference to host diet and parasitoid toxin

Summary Varying host reaction of the house fly, Musca domestica L., to parasitism by the braconid Aphaereta pallipes (Say) was chiefly correlated with the diet of the host. Some evidence was found that implicated the strain of the host, the rearing temperatures, the ages of the parasitoid and the host, and the site of oviposition. Though development of A. pallipes embryos was inhibited before they became encapsulated with melanin within the host, the presence of the parasitoid and (or) the effect of its paralyzing toxin that was injected into the host just before oviposition prevented normal larval, pupal, or adult development of the six house fly strains tested. A considerable increase of parasitoid survival occurred when M. domestica larvae were reared on a chemically defined diet.

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Zusammenfassung Musca domestica L. reagierte unterschiedlich auf die Parasitierung durch die Braconide Aphaereta pallipes (Say). Die verschiedenen Reaktionen waren im wesentlichen mit der Art der Wirtsnahrung korreliert. Daneben finden sich Hinweise, daß auch der Wirtsstamm, dessen Zuchttemperatur, das Alter von Parasit und Wirt und der Eiablageort des Parasiten die Reaktionen beeinflussen. Obgleich die Entwicklung von Parasitenembryonen bereits gehemmt war, ehe sie innerhalb des Wirtes von Melanin eingeschlossen wurden, so verhinderten doch die Parasiten-embryonen und/oder die Wirkung der vor der Eiablage abgegebenen Paralysierungstoxine die normale Entwicklung der Wirte aus sechs Fliegenstämmen. Eine beträchtliche Steigerung der Überlebensrate der Parasiten trat ein, wenn M. domestica-Larven in einem Gemisch chemisch genau definierter Nahrung gezogen wurden.

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With 8 Figures in the Text

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Formerly National Research Council Postdoctorate Fellow, Research Institute, Belleville, Ontario.