Search PubMed⌕ Search

Biomedical subjects

J J Berger

Publications and source records attributed to J J Berger.

26 records · Page 2Linked to original sources
PubMed1986

[Mechanisms of the origination of hypersegmented (hyperdiploid) neutrophils in rats as affected by cyclophosphamide].

Feulgen cytophotometry has revealed tetraploid DNA content in some hypersegmented mature granulocytes in rat peripheral blood after two weeks of daily injections of cyclophosphamide (20 mg/kg of body weight). In bone marrow of rats which were given the preparation for 7 days myeloblasts, promyelocytes and myelocytes are blocked in G2 phase of the mitotic cycle. About 50% of metamyelocytes, bands and segmented granulocytes are also tetraploid. Thus cyclophosphamide has induced tetraploid hypersegmented neutrophils in rats as a result of maturation of G2 blocked proliferative pool granulocytes.

Animals↗
PubMed1984

Similar growth pattern of mouse mammary epithelium cultivated in collagen matrix in vivo and in vitro.

Mouse mammary ductal cells cultured in type I collagen gels give rise to three-dimensional multicellular outgrowths consisting of thin spikes which are often branched, and which may have pointed or blunt ends. The significance of these spikes to normal ductal morphogenesis has been unclear, since identical structures are not known to occur in vivo; conversely, it has not been possible to maintain in gel culture the highly structured end buds which are characteristic of ductal elongation in the animal. In order to evaluate whether the pattern of radiating spikes observed in collagen gel cultures results from chemical or physical peculiarities of the culture environment, a small volume of unpolymerized type I collagen solution was injected into mammary gland-free fat pads of young adult mice. After the bubble of collagen had polymerized, an implant of mammary ductal epithelium was introduced into the center of the gel. Histological examination of the implants after 3 to 6 days of growth revealed numerous small epithelial spikes, similar to those observed in gel culture, extending into the fibrous matrix. The early stages of regeneration of mammary implants placed in gland-free fat pads were then examined without the addition of exogenous collagen. In cases where the epithelium happened to contact a fibrous region of the fatty stroma, spikes were also seen to form in these natural collagenous substrates. Whether or not exogenous collagen was used, normal end buds were formed only when epithelial spikes contacted adipocytes. It was concluded that the three-dimensional pattern of radiating tubules in collagen gels in vitro is not merely an artifact of culture, but has a counterpart in vivo whereever regenerating mammary epithelium is surrounded by fibrous stroma. A model is presented in which the pattern of epithelial outgrowth is determined by the physical characteristics of the surrounding stroma; in collagen matrix a comparatively primitive and unspecialized type of morphogenesis occurs which may not require the participation of stromal cells. In contrast, epithelial-adipocyte interactions appear to be necessary for the formation of end buds and subsequent morphogenesis of fully structured mammary ducts.

Animals↗
PubMed1984

Perioperative changes in blood pressure and heart rate.

In order to evaluate the possible physiologic significance of intra- and postoperative hypotension, we monitored arterial blood pressure and heart rate continuously for 36 hr starting the night before and ending the morning after operation in 34 gynecologic patients. The lowest pressures that occurred during physiologic sleep were compared with the lowest arterial pressures that occurred during anesthesia without deliberate hypotension. Two values were calculated: a preoperative baseline pressure, i.e., the average value recorded during the second hour of monitoring on the night before surgery, and a preanesthetic standard pressure, i.e., the average value of 15 consecutive measurements made at 1-min intervals in the operating room before the induction of anesthesia. The results indicate that a systolic pressure 10% below the PAS during anesthesia does not constitute physiologically significant hypotension because this range resembles the range that occurs spontaneously during unmedicated sleep or sleep aided with a mild hypnotic. These physiologic nadirs in blood pressure are assumed to be tolerated well by the patient. Intraoperative pressures in elderly patients frequently drifted below sleep-associated levels of blood pressure and may, therefore, constitute physiologically significant hypotension.

Age Factors↗
PubMed1982

Diurnal rhythms in developing ducts of the mouse mammary gland.

DNA synthesis (LI) and mitotic activity (MI) were studied at different times of the day in the developing mammary gland end bud of the postnatal mouse. Both LI and MI displayed a clear diurnal variation. Animals studied at the middle of the 12-hr dark cycle showed a LI 2.1-2.6 times that of the tissue from the middle of the 12-hr light cycle. Intermediate values were obtained in tissue sampled midway between these extremes. Mitotic activity was studied 4 hr after the peak and trough of LI and exhibited a corresponding variation. These diurnal vdle of the 12-hr dark cycle showed a LI 2.1-2.6 times that of the tissue from the middle of the 12-hr light cycle. Intermediate values were obtained in tissue sampled midway between these extremes. Mitotic activity was studied 4 hr after the peak and trough of LI and exhibited a corresponding variation. These diurnal vdle of the 12-hr dark cycle showed a LI 2.1-2.6 times that of the tissue from the middle of the 12-hr light cycle. Intermediate values were obtained in tissue sampled midway between these extremes. Mitotic activity was studied 4 hr after the peak and trough of LI and exhibited a corresponding variation. These diurnal variations may be related to cyclic changes in secretion of pituitary hormones or other peptide growth factors, but variation between individual end buds in the same animal is more likely a result of morphogenetic interactions at the tissue level.

Animals↗
PubMedDate not supplied

Stromal DNA synthesis is stimulated by young, but not serially aged, mouse mammary epithelium.

Ductal elongation in young, proliferating mouse mammary gland is associated with a zone of DNA synthesis in stroma surrounding the end buds. In contrast, slowly growing, serially aged tissue fails to elicit a significant elevation of stromal DNA synthetic activity. Since fatty stroma is required for normal mammary growth and morphogenesis, this altered interaction may be a significant factor in the aging of mammary epithelium.

Adipose Tissue↗
PubMedDate not supplied

The use of frozen intravenous crystalloid solutions as the refrigerant for shipping blood.

The authors studied whether cooled sterile intravenous crystalloid solutions could be used to refrigerate red cells during shipment. Six 1000-ml bags of 0.9 percent normal saline and lactated Ringers (RL) solutions were supercooled and tested separately at temperatures ranging from 1 to -78 degrees C, with either 5 or 30 units of packed red cells (PRBCs). The PRBCs were shipped in a standard military container that permitted separation of the supercooled solutions from the PRBCs. Cooling RL solutions to 6 degrees C and to -22 degrees C maintained acceptable storage temperatures of the PRBC for 36 and 50 hours, respectively, and did not cause visible damage to the units. No significant changes were observed in various biochemical measurements of the cells and plasma. Cooling the RL solution to -78 degrees C caused a significant (p less than 0.05) increase in plasma potassium concentration. The effectiveness of the crystalloid solutions in refrigerating blood varied with the ratio of the number of PRBCs to the volume of cooled solutions and with the ambient temperature surrounding the container. The results of this study suggest that cooled intravenous crystalloid solutions can be used as refrigerants for PRBCs during shipment.

Blood Preservation↗