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Biomedical subjects

B Barber

Publications and source records attributed to B Barber.

At least 37 records · Page 2Linked to original sources
PubMed1987

Pacemaker region in a rhythmically contracting embryonic epithelium, the enveloping layer of Oryzias latipes, a teleost.

The primary objectives of this study were to determine the embryonic stage at which the Oryzias latipes enveloping layer (EVL) begins to contract rhythmically, and to determine where these contractions arise within the EVL. Using time-lapse video recording, we showed that the contractions begin at stage 14 (the stage of the embryonic shield) and arise in the ventral region of the EVL, which is centered at 180 degrees longitude from the embryonic shield. We have called this the pacemaker region for the contractions. Using fluorescein diacetate as a vital stain, we showed that the ventral region of the EVL continues to act as a pacemaker even after the EVL is detached from the rest of the egg. Rhythmic contractile activity ceased when we removed a group of about 130 cells--10% of the total EVL--from the pacemaker region; comparably large wounds elsewhere had no effect on the contractions. When we cut detached EVLs into ten pieces, only 2.4 +/- 1.8 (mean +/- SD, N = 11) of them contracted rhythmically, even though a considerably larger proportion of the EVL cells participate in the contractions in undisturbed blastoderms. We conclude that the pacemaker cells are necessary for rhythmic contractile activity and that cells outside this region do not contract spontaneously. The contractile waves are propagated at a velocity of 14-54 microns sec-1. This value, which is two to three orders of magnitude slower than the propagation of epithelial action potentials, is similar to the rate of propagation of waves of increased cytosolic Ca2+ in other systems. We propose that the medaka EVL is a good system in which to study certain aspects of epithelial morphogenesis.

Animals↗
PubMed1987

Dose of human menopausal gonadotropin influences the outcome of an in vitro fertilization program.

This study compares outcomes of in vitro fertilization (IVF) in two groups of 57 patients when either 2 (group 1) or 3 (group 2) ampules of human menopausal gonadotropin (hMG) were administered daily. Treatment began on day 3 of the cycle and was discontinued when at least 2 follicles attained diameters greater than or equal to 1.5 cm. Human chorionic gonadotropin (hCG) was given either 24 or 48 hours after the last dose of hMG. Although serum estradiol levels were lower in group 1, the average number of oocytes retrieved (3.2 versus 2.9), fertilized (1.9 versus 2.0), and cleaved (1.7 versus 1.8) per completed cycle did not differ between groups 1 and 2. Likewise, the number of oocytes that fertilized abnormally was similar in both groups (0.5 versus 0.3/cycle). However, the number of atretic oocytes (0.03 versus 0.5/cycle) and the percent of oocytes recovered from the cul-de-sac (0 versus 7.2%) were significantly (P less than 0.05) lower in group 1. In group 1, administration of hCG 48 hours after the last dose of hMG was associated with a higher number of cleaving embryos (2.1 versus 1.5/cycle) and a higher pregnancy rate (34.8 versus 14.7%; P less than 0.05) when compared with injection at 24 hours. In group 2, the interval between hMG and hCG did not influence these results. Together, the associations between fewer oocytes that were atretic or recovered from the cul-de-sac, and a trend toward a higher pregnancy rate, suggest that follicular recruitment with 2 ampules of hMG is more appropriate than 3 ampules in an IVF program.

Chorionic Gonadotropin↗
PubMed1985

Pulmonary epithelial permeability after inhaling saline, distilled water "fog" and cold air.

It is recognized that hyperventilation of cold air and the inhalation of fine mists of distilled water provoke significant bronchoconstriction in the asthmatic individual, yet little is known as to how these provocations affect the structural integrity of the alveolar epithelial membrane. In 11 normal subjects, the following effects have been studied: cold air hyperventilation for three minutes, inhalation of 80 L of ultrasonically nebulized distilled water "fog," and 80 L of isotonic saline "fog" on the half time clearance (T1/2) from the alveoli of technetium 99m diethylene triamine penta acetate (DTPA), inhaled as an aerosol. The DTPA T1/2 provided a measurement of pulmonary epithelial permeability.

Aerosols↗
PubMed1983

Issues for informed consent.

Informed consent from a cytapheresis donor is the culmination of a complex decision making process during which the blood collecting agency presents sufficient information to enable the donor to make a free choice whether or not to donate. The institution bears the responsibility for providing all information relevant to the donor's decision, whether favorable or unfavorable. At no other stage of its contact with the donor can a collecting agency discharge its public trust more meaningfully. Thus, informed consent is not only the greatest altruistic expression from the unrelated volunteer donor, or the expression of deepest commitment to the family for the related donor, it is also the fullest expression of the value which the institute places on the autonomy of the donor. The foundation upon which the concept of informed consent rests has been laid by law, medicine, government, ethics, and religion. Although the procedures accompanying the informed consent process appear bureaucratic, they should be viewed as the components of a remarkable, dynamic process. The consent of a donor to undergo cytapheresis is an eloquent statement of the value he or she places on the importance of another human being's life.

Blood Component Removal↗
PubMed1983

Gastroesophageal fundoplication improves symptoms in refractory asthma.

Gastroesophageal (GE) reflux has been etiologically linked to a number of pulmonary diseases. Subclinical pulmonary aspiration from nocturnal GE reflux has been proposed as a cause of asthma. A patient with severe asthma, refractory to conventional medical therapy, is presented. The asthma was presumed to be secondary to gastroesophageal reflux and indeed the patient became asymptomatic following a Nissen fundoplication procedure. This case report documents that surgical correction of GE reflux may be an appropriate therapeutic maneuver in asthmatics who subclinically aspirate as a consequence of GE reflux.

Adult↗
PubMed1977

On the determination of isozyme levels in preparations containing cytoplasmic and mitochondrial aspartate aminotransferase.

A spectrophotometric assay has been developed for the determination of the content of each isozyme of aspartate transaminase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) in physiological fluids or tissue extracts. The methods relies on the ability of adipate, at low pH and ionic strength to inhibit the cytoplasmic isozyme but not the one from mitochondria. Two assays are necessary, one at pH 8.0 which measures the content of both isozymes and another at low pH which measures primarily the amount of mitochondrial isozyme. Results obtained by this simple procedure match those in which each isozyme is inhibited by its antibody. The validity of the results obtained by the new method was tested at different ratios of cytoplasmic:mitochondrial isozyme and with tissue extracts. Since the amounts of each isozyme determined by radial immunodiffusion match those values gathered by following enzymatic activity, it is concluded that the quantity of each isozyme obtained from its respective catalytic activity must represent the total protein content of each isozyme in a given sample.

Animals↗