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Biomedical subjects

L Jacobson

Publications and source records attributed to L Jacobson.

At least 199 records · Page 11Linked to original sources
PubMed1981

Improved technique for investigation of cell metabolism by 31P NMR spectroscopy.

31P NMR studies on microorganisms have been carried out with the cells embedded in agarose gel. The novel use of the gel for the NMR studies has advantages over the usual liquid suspensions in terms of improved reproducibility of data and cell viability, with no net loss of spectral quality. Polyphosphate formation in Escherichia coli was monitored continuously for up to 24 h and metabolic changes in yeast for 6 h. Changes of the intracellular pH during glycolysis in yeast were determined from the chemical shift of the internal Pi. NMR titration curves of Pi in the presence of Mg2+ indicate uncertainties in internal pH values estimated by this technique.

Escherichia coli↗
PubMed1981

A study of intracuff pressure measurements, trends and behaviour in patients during prolonged periods of tracheal intubation.

Intracuff pressure (c.p.) was measured continuously in 12 patients during prolonged periods of tracheal intubation. High residual volume--low pressure (floppy) and low residual volume--high pressure (conventional) cuffs were studied. The mean baseline c.p. at minimal occluding pressure was significantly smaller in floppy cuffs than in conventional cuffs. With coughing, the peak pressures in both cuff types were much greater than the baseline pressures but did not differ significantly from each other. On the basis of our observations, we recommend a simplification of the test methods for cuffs and tube collapse. We believe universal testing to 300 mm Hg (40 kPa) to be reasonable and to incorporate a realistic safety factor. Intracuff pressure tends to diminish with time, but there is a poor correlation between the rate of pressure decrease and elapsed time. As this decrease is not accurately predictable, gas should be added to the cuff as required, rather than at intervals. Other features of cuff behaviour are discussed and suggestions made to explain some anomalies occasionally observed in the cuff pressure behaviour pattern.

Cough↗
PubMed1981

Inhibitory effects of 2,3,5-triiodobenzoic Acid on ion absorption, respiration, and carbon metabolism in excised barley roots.

The ability of 2,3,5-triiodobenzoic acid (TIBA) to alter ion absorption, respiration, carbon metabolism, and the permeability of the cell membranes of excised barley roots has been examined. Roots pretreated in either H(2)O, KCl, or TIBA followed by treatment in KCl, TIBA, or KCl and TIBA demonstrated that inhibition of ion uptake due to TIBA was reversible. These studies also suggest that ions already accumulated within the vacuole remain sequestered after the addition of TIBA, whereas cytoplasmic ions leak out into the external medium. A 20-minute lag period was present prior to the onset of inhibition of O(2) consumption by TIBA. A b-type cytochrome from corn that is apparently associated with the plasmalemma and possibly involved in respiration or ion uptake, or both, was unaffected by TIBA. The addition of TIBA to treatment solutions resulted in the synthesis and accumulation of ethanol. Analysis of organic acids showed that only the malate concentration was affected by treatment with TIBA. A reduction of 26% was noted for malate in the presence of 2 micromolar TIBA. These combined results suggest that the inhibitory action of TIBA in barley roots involves an alteration of mitochondrial respiration and not a direct depolarization of the plasmalemma.

Journal Article↗
PubMed1981

Leiomyomatosis peritonealis disseminata.

Leiomyomatosis peritonealis disseminata (LPD) is a rare disease characterized by the development of multiple subperitoneal leiomyomas, which are widespread in the peritoneal cavity. Of the previously reported LPD cases, nine patients were pregnant, two were on oral contraceptives and one had a granulosa-cell tumor. The thirteenth documented case is presented here (this patient had been on oral contraceptives for 13 years). Thus, hormonal factors might be involved in the pathogenesis of LPD. Controversy prevails as regards the cellular origin of LPD. The disorder has a grossly malignant appearance, but has a benign histology and a favorable prognosis; so a correct diagnosis is imperative. In almost all the previously reported LPD patients, hysterectomy and bilateral salpingo-oophorectomy have been performed, but salpingo-oophorectomy is probably unnecessary, at least in premenopausal patients.

Adult↗
PubMed1980

Differential diagnosis of acute pelvic inflammatory disease.

Laparoscopic investigations have shown that clinical symptoms and signs in cases of acute pelvic inflammatory disease (acute salpingitis) show considerable variation and seem to a great extent to be nonspecific. Diagnosis based on clinical criteria alone is, therefore, unacceptably unreliable. Different intrapelvic disorders and acute infections limited to the lower genital tract (LGTI) represent substantial differential diagnostic problems. The routine use of laparoscopy is currently the best method for solving these problems but its broader application is restricted by several factors. Determination of specific genital isoamylases obtained at vaginal puncture of the cul-de-sac seems to represent a promising and specific laboratory test for differentiating between acute PID and LGTI that simulates acute PID.

Diagnosis, Differential↗
PubMed1980

Inhibition of respiration and ion uptake by 2,3,5-triiodobenzoic Acid in excised barley roots.

The addition of 1 micromolar 2,3,5-triiodobenzoic acid (TIBA) to solutions containing KCl resulted in the inhibition of K and Cl uptake in excised barley roots. The effectiveness of TIBA as an inhibitor increased as the pH of the treatment solution decreased and approached the pK(a) of TIBA. A lag period of approximately 20 minutes existed prior to the onset of TIBA induced inhibition of ion uptake. Respiratory activity was also inhibited by TIBA. The data suggest that in this material, TIBA functions by entering the cytoplasm and inhibiting metabolism. Comparisons made on the effect of added Ca, showed that at pH 5.7 and higher, Ca had no effect on ion uptake whereas at lower pH values the presence of Ca enhanced uptake by offsetting the deleterious effects of H(+).

Journal Article↗
PubMed1979

13C NMR analysis of methionine sulfoxide in protein.

The 13C epsilon NMR signal of methionine sulfoxide is 22.6 ppm downfield from that of methionine. This affords a method by which the extent of methionine oxidation can be determined in intact protein. We demonstrate the utility of this approach with beta-galactosidase enriched with 13C in its methionine methyls.

Chloramines↗
PubMed1979

Some characteristics of transcutaneously monitored oxygen partial pressure in normal newborns.

The transcutaneous oxygen partial pressure (PtcO2) was monitored in 50 healthy, normally and spontaneously delivered newborns. Measurements were performed during the first to fourth day of life. The electrode temperature was 44.5 degrees C. The mean PtcO2 level recorded during about 45 min was 9.2 kPa (S.D. 1.4) recorded from the minute-to-minute values. The PtcO2 level normally oscillated to a certain extent and the oscillations were closely related to the breathing pattern of the patient. When the patient fell asleep during measurement, the normal oscillating pattern was replaced by a "silent pattern". During crying, the PtcO2 level showed four main reaction aptterns. A decrease in the PtcO2 level could be observed during breast-feeding. One child, recently fed, vomited a small amount of breast milk after a short period of crying and apparently had a laryngospasm, shown by a sudden drop in the PtcO2 level without any other signs of discomfort. The study shows that PtcO2 (and thus also PaO2) very sensitively reacts to changes in activity. This implies that earlier used methods for determination of PaO2 might give values that are not representative for the steady state as the sampling method per se might influence the recorded PO2 value.

Breast Feeding↗
PubMed1979

The influence of different electrode temperatures on the recorded transcutaneous Po2 level.

The technique of transcutaneous monitoring of oxygen partial pressure (PtcO2), first described in 1969, provided a new clinical possibility for continuous and noninvasive surveillance of changes in the oxygenation of the organism. To obtain optimal arterialization of the skin and thus a relieable recording, the electrodes used have been supplied with microheating elements. The electrode temperature used implies the risk of producing burns; this is especially true when the measurements are performed in patients with decreased skin circulation or in immature children with a thin and vulnerable skin. Thus, a careful choice of the electrode temperature is important in PtcO2 recording; a higher temperature is desirable for obtaining adequate arterialization, whereas a lower temperature is preferred for reducing the risk of burns. The electrode temperatures described for PtcO2 measurements range from 42--45 C. A systematic study with the Radiometer TCM 1 equipment showed that changing the electrode temperature influences the OtcO2 in a systematic way within the temperature range 43.0--45.0 C. The study also showed that simultaneous measurements obtained from two electrodes with different temperatures showed a highly parallel course and a comparable oscillating pattern within this temperature range. The results of the present study suggest that an electrode temperature of 44.5 C may be the most appropriate for this equipment in clinical applications with newborns.

Electrodes↗