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Biomedical subjects

J Gottlieb

Publications and source records attributed to J Gottlieb.

At least 55 records · Page 3Linked to original sources
PubMed1988

Flow recovery and vasoconstriction following microvascular anastomosis.

A variety of factors may limit blood flow recovery in free flaps. In this study one of these factors, vasoconstriction, and its consequences was investigated. Blood flow recovery at the skin level following microvascular anastomosis was evaluated in the rat orthotopic groin free flap model using a laser Doppler velocimeter. In a study of 41 rats, measurements of external vessel diameter were made using a standard machinist's drum micrometer. After each flap was raised and the anastomoses performed, the field was flooded with either saline, 2% lidocaine, or 0.75% bupivacaine (Marcaine). The vascular clamps were released and measurements of flow were recorded as a percentage of the control value. In the saline-control group, it was found that flow gradually recovered to 91% of the preoperative value in an average time of 5.7 minutes. Six of 12 vessels in this group were found to have measurable spasm of the pedicle. In the lidocaine-treated group, flow recovered to 93% of the preoperative value in an average of 5.0 minutes. Two of 15 vessels had measurable spasm. In the Marcaine-treated group, flow recovered to 94% of the preoperative value in an average of 5.1 minutes. Three of 14 vessels showed measurable spasm. The final level of flow recovery showed no statistical difference in any of these groups whether or not spasm was present. We therefore conclude that, in this model, alteration in the diameter of the vascular pedicle as a consequence of performing a microvascular anastomosis affects only the time it takes to achieve ultimate recovery of flow but does not affect its final level.

Anastomosis, Surgical↗
PubMed1988

In vitro excision of adeno-associated virus DNA from recombinant plasmids: isolation of an enzyme fraction from HeLa cells that cleaves DNA at poly(G) sequences.

When circular recombinant plasmids containing adeno-associated virus (AAV) DNA sequences are transfected into human cells, the AAV provirus is rescued. Using these circular AAV plasmids as substrates, we isolated an enzyme fraction from HeLa cell nuclear extracts that excises intact AAV DNA in vitro from vector DNA and produces linear DNA products. The recognition signal for the enzyme is a polypurine-polypyrimidine sequence which is at least 9 residues long and rich in G.C base pairs. Such sequences are present in AAV recombinant plasmids as part of the first 15 base pairs of the AAV terminal repeat and in some cases as the result of cloning the AAV genome by G.C tailing. The isolated enzyme fraction does not have significant endonucleolytic activity on single-stranded or double-stranded DNA. Plasmid DNA that is transfected into tissue culture cells is cleaved in vivo to produce a pattern of DNA fragments similar to that seen with purified enzyme in vitro. The activity has been called endo R for rescue, and its behavior suggests that it may have a role in recombination of cellular chromosomes.

DNA, Viral↗
PubMed1988

A method to determine methylmethacrylate in air.

To determine the air concentrations of methylmethacrylate monomer and thus obtain information about the safety in the operating theater, a methylmethacrylate Dräger tube was used in connection with a bellows pump. This method gives an instantly readable value correlated with more complicated gas chromatographic measurements.

Air Pollutants, Occupational↗
PubMed1987

Locus of hypoxic vasoconstriction in isolated ferret lungs.

To determine whether hypoxic pulmonary vasoconstriction (HPV) occurs mainly in alveolar or extra-alveolar vessels in ferrets, we used two groups of isolated lungs perfused with autologous blood and a constant left atrial pressure (-5 Torr). In the first group, flow (Q) was held constant at 50, 100, and 150 ml.kg-1 X min-1, and changes in pulmonary arterial pressure (Ppa) were recorded as alveolar pressure (Palv) was lowered from 25 to 0 Torr during control [inspired partial pressure of O2 (PIO2) = 200 Torr] and hypoxic (PIO2 = 25 Torr) conditions. From these data, pressure-flow relationships were constructed at several levels of Palv. In the control state, lung inflation did not affect the slope of the pressure-flow relationships (delta Ppa/delta Q), but caused the extrapolated pressure-axis intercept (Ppa0), representing the mean backpressure to flow, to increase when Palv was greater than or equal to 5 Torr. Hypoxia increased delta Ppa/delta Q and Ppa0 at all levels of Palv. In contrast to its effects under control condition, lung inflation during hypoxia caused a progressive decrease in delta Ppa/delta Q, and did not alter Ppa0 until Palv was greater than or equal to 10 Torr. In the second group of experiments flow was maintained at 100 ml.kg-1 X min-1, and changes in lung blood volume (LBV) were recorded as Palv was varied between 20 and 0 Torr. In the control state, inflation increased LBV over the entire range of Palv. In the hypoxic state inflation decreased LBV until Palv reached 8 Torr; at Palv 8-20 Torr, inflation increased LBV.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Nitrendipine attenuates the pulmonary vascular remodeling and right ventricular hypertrophy caused by intermittent hypoxia in rats.

We designed experiments to determine whether intermittent hypoxia would produce significant pathologic and physiologic changes in rats and whether pretreatment with a calcium channel blocker, nitrendipine, would reduce the pulmonary vascular remodeling and right ventricular hypertrophy caused by intermittent hypoxia. Intermittent exposure to hypobaric hypoxia (0.5 atmospheres) 10 h a day for 30 days increased the hematocrit (65 +/- 1 versus 42 +/- 1%, mean +/- SEM), right ventricular systolic pressure (33 +/- 1 versus 20 +/- 1 mmHg), and right ventricular weight adjusted for body weight (RV/BW) (126 +/- 6 versus 60 +/- 2 mg/100 g) in male Sprague-Dawley rats. Intermittent hypoxia also increased the percentage of small pulmonary vessels with muscle (76 +/- 3 versus 19 +/- 5%) and the thickness of the vessel wall as a percentage of the total vessel diameter (34 +/- 1 versus 22 +/- 1%). Nitrendipine (10 mg/kg) prevented the acute increase in right ventricular systolic pressure caused by hypoxia. Chronic treatment with nitrendipine (10 mg/kg given twice a day by gavage for 30 days) significantly reduced the increase in hematocrit (61 +/- 1 versus 65 +/- 1%), right ventricular systolic pressure (29 +/- 1 versus 33 +/- 1 mmHg), and RV/BW (108 +/- 4 versus 126 +/- 6 mg/100 g) caused by hypoxia. Chronic treatment with nitrendipine also reduced the percentage of small pulmonary vessels with muscle (38 +/- 8 versus 76 +/- 3%) and prevented the increase in vessel wall thickness (20 +/- 2 versus 34 +/- 1%). Thus, nitrendipine treatment significantly reduces the right ventricular hypertrophy and pulmonary vascular changes caused by intermittent hypoxia.

Animals↗
PubMed1985

The relationship of the great auricular nerve to the superficial musculoaponeurotic system.

We reported in 1980 the course of the great auricular nerve from the perspective of the surgeon performing rhytidectomy using the platysma flap operation. Since the superficial musculoaponeurotic system (SMAS) operation has become increasingly popular during the interim, we reviewed the course of the nerve with regard to our current operative dissection. We found, in both clinical cases and anatomical specimens, that the great auricular nerve is deep enough to allow safe division of the SMAS along the anterior border of the sternocleidomastoid muscle.

Face↗
PubMed1984

Diagnostic utility of pleural fluid eosinophilia.

It has been stated that pleural fluid eosinophilia (defined as greater than 10 percent eosinophils in the pleural white cell differential count) is not helpful in the diagnosis of exudative effusions. By review of the recent literature, it was found that pleural fluid eosinophilia was associated most often with idiopathic effusions or with air previously introduced into the pleural space. Also, a high proportion of "idiopathic" and benign asbestos effusions were characterized by pleural fluid eosinophilia, a previously unrecognized phenomenon. The diagnostic utility of finding eosinophils in the pleural space was assessed from its impact on prior probabilities of disease. Estimates of pretest likelihoods of malignant versus nonmalignant pleural effusions and the prevalence of eosinophilia in effusions of known cause were obtained from extensive literature review. These were modified by using Bayes' rule to estimate the revised probability of disease in the presence of an eosinophilic effusion. The presence of pleural fluid eosinophilia considerably reduced the probability of malignancy or tuberculosis and increased the likelihood of an underlying benign disorder. Pleural fluid eosinophilia is a useful finding that can aid in the diagnosis of an exudative pleural effusion.

Eosinophilia↗
PubMed1983

Psychophysiological response patterns in vascular and muscle-contraction headaches.

The psychophysiological response patterns of 43 headache subjects were compared to the response patterns of 11 nonheadache control subjects. The headache group was composed of subjects diagnosed as suffering from either muscle-contraction (N = 11), classic migraine (N = 11), common migraine (N = 11), or mixed (N = 10) headache. Discriminant analyses indicated that (1) the headache groups could be perfectly differentiated from the nonheadache control group after a period of relaxation and during a period of psychological stress and (2) the stress condition differentiated among the various headache groups. In general, the headache groups showed a higher level of arousal and were more responsive to stress. Also, the response pattern profiles differed among the headache groups in the stress condition. Muscle-contraction subjects tended to respond with higher frontal EMG, and classic migraine and mixed headache groups tended to respond with larger cardiovascular responses.

Adult↗
PubMed1983

Naturalistic studies of institutionalized profoundly or severely mentally retarded persons: the relationship of density and behavior.

Observational data were collected on institutionalized mentally retarded people to determine the relationship between density and behavior in order to discover (a) in what size groups do such persons typically congregate? and (b) what effect does density have on their behavior within that group? Results showed that (a) this population was alone or only with peers more than with staff by a 3:1 ratio; (b) when they were with staff, they were with two or more peers 75 percent of the time; and (c) when they were not with staff, they were with two or more peers more than they were alone or with only one other peer. Results also showed that certain types of behavior changed in frequency as density changed.

Adolescent↗
PubMed1982

Development of school-age children's stereotypic attitudes toward mentally retarded children.

The developmental changes in the structure of attitudes toward mentally retarded children in elementary-school-aged students were investigated. Four orthogonal factors characterized their responses: General Negative Evaluation, General Positive Evaluation, Likeability, and Unhappiness. For the most part, increased age was associated with a decrease in negative stereotypes and an increase in a specific stereotype. The results were discussed in terms of contradictory findings in previous attitudinal research.

Age Factors↗