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Biomedical subjects

F L Jackson

Publications and source records attributed to F L Jackson.

31 records · Page 2Linked to original sources
PubMed1981

Enzyme-linked immunosorbent assay for detection of pertussis immunoglobulin A in nasopharyngeal secretions as an indicator of recent infection.

An enzyme-linked immunosorbent assay was developed for detection of immunoglobulin A (IgA) antibody to Bordetella pertussis (PsIgA) in nasopharyngeal secretions as an indicator of recent infection. Secretion specimens submitted for pertussis culture were examined for PsIgA by this technique. Of 348 specimens tested, B. pertussis was cultured from 57, and PsIgA was detected in 8 culture-positive and 40 culture-negative specimens. The average time between onset of symptoms and specimen collection for the culture-positive, PsIgA-negative specimens was 10 days; for the culture-positive, PsIgA-positive specimens, 15 days; and for the culture-negative, PsIgA-positive specimens, 36 days. Examination of paired samples available from several culture-proven cases demonstrated conversion from a negative PsIgA in the early sample to a positive PsIgA in the follow-up sample. Our results indicate that PsIgA is produced during natural human infection and does not arise as a result of parenteral vaccination. PsIgA usually appears in the nasopharyngeal secretions during the second or third week of illness and persists for at least 3 months. The detection of PsIgA in secretions may be a valuable diagnostic aid in culture-negative patients with pertussis.

Adult↗
PubMed1980

Influence of the pineal gland on the reproductive system of the male house mouse.

Procedures designed to express pineal-mediated antigonadotropic activity were performed upon male house mice. Neither blinding nor blinding plus olfactory bulbectomy of house mice resulted in testicular involution within 12 weeks. The pineal gland appears to be of little significance to reproduction in the house mouse.

Animals↗
PubMed1979

A correlation between a spectrophotometric quantitation of rabbit spermatozoan motility and velocity.

Rabbit sperm motility was measured spectrophotometrically and a sperm motility index (SMI) was obtained. A comparative analysis between the SMI values and the velocity of motile sperm (obtained by time lapse photography of sperm tracks) was performed. The SMI specifically was compared to the mean velocity of the first 300 sperm cells observed and to the mean velocity of just the first 300 progressively motile sperm cells. In both comparisons, the SMI was highly correlated to the sperm track length (sperm velocity). In addition, a modification of the spectrophotometric procedure is described which allows measurements of the SMI to be made on semen extended into egg-yolk glycerine cryopreservation agents.

Animals↗
PubMed1976

Antibody-coated bacteria in the urine of preschool and school-aged girls with asymptomatic bacteriuria.

Urine samples from 3564 girls aged 2 to 13 years were screened for evidence of infection. Cultures were positive (bacteria count, more than 10(5)/ml) in 61 (1.7%) by the dipslide method and in 55 (1.5%) by standard culture techniques. In 13 (23.6%) of the 55, antibody-coated bacteria (ACB) were detected in the urine. The clinical, bacteriologic, radiologic and urinalysis findings in children with ACB were no different from those in children in whom the bacteria were not coated. Direct examination of uncentrifuged urine under high power revealed one or more bacteria per two high-power fields in 96% of infected urine samples and in only 7% of noninfected samples. Five or more leukocytes per high-power field in centrifuged urine were detected in 36.7% of infected urine samples but not in noninfected samples. The ACB test did not differentiate between asymptomatic bacteriuria with parenchymal scarring or vesicoureteral reflux or both and asymptomatic bacteriuria without these abnormalities.

Adolescent↗
PubMed1975

Bacterial peritonitis and the bursting strength of intestinal anastomoses.

In order to study the bursting strength of intestinal anastomoses, resection of a wedge of ileum and creation of an anastomosis were performed, and peritonitis was induced in five groups of rats. Peritonitis was induced by intraperitoneal injection of bacterial suspensions of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Clostridium welchii, and the exteriorized ileal loop in each rat was regularly inspected for peritoneal exudation, adhesions, hyperemia, obstruction, leakage and bursting strength. All bowel anastomoses performed in the presence of peritonitis were weaker than those done in a sterile field (control group) and the type of organism influenced the strength of the anastomosis and the histopathologic changes; in this study the weakest anastomoses were associated with E. coli infection.

Animals↗
PubMedDate not supplied

Role of the pineal in the alteration of hamster Sertoli cell responsiveness to FSH during testicular regression.

Testicular regression was induced in adult hamsters by optic enucleation, short photoperiod, or melatonin injections. The melatonin injected group, while undergoing testicular regression, showed a quite different time course from the optic enucleated and short photoperiod groups. All three methods resulted in the restoration of Sertoli cell responsiveness to FSH in vitro from the adult level to that of Sertoli cells from immature hamsters 18-20 days of age. the melatonin injected group showed a shift in testis weight which resulted in a half maximal restoration of Sertoli cell responsiveness to FSH compared to the other groups. This restoration of Sertoli cell responsiveness to FSH was blocked by pinealectomy. These data indicate that the pineal has a specific (but not necessarily direct) effect on Sertoli cell function. In addition, the effect of melatonin injections is qualitatively but not quantitatively similar to optic enucleation and short photoperiod both with regard to testicular regression and alteration of Sertoli cell response.

Animals↗
PubMedDate not supplied

Attenuation of experimental autoimmune encephalomyelitis by Compound 48/80 in Lewis rats.

The appearance of increased levels of histamine in the central nervous system (CNS) concomitant with the development of clinically significant acute experimental autoimmune encephalomyelitis (EAE) in male Lewis rats suggests that CNS-associated mast cells may mediate acute EAE in Lewis rats. We now report that, compared to controls, rats with acute EAE exhibit fewer detectable mast cells in their dura mater and velum interpositum. In addition, intracisternal, but not intraperitoneal administration of Compound 48/80 just prior to the appearance of clinical signs of acute or recurrent EAE in male and female rats, respectively, significantly attenuates the clinical severity of both forms of EAE. These results further support the hypothesis that CNS-associated, but not peripheral mast cells are mediators or modulators of acute and recurrent EAE in Lewis rats.

Animals↗