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Biomedical subjects

M Baum

Publications and source records attributed to M Baum.

At least 397 records · Page 22Linked to original sources
PubMed1987

Improved in vitro diagnosis of allergy to Alternaria tenius and Cladosporium herbarum.

To improve the in vitro diagnosis of mould allergy 22 children suffering from allergic asthma caused by Alternaria tenius and/or Cladosporium herbarum as proven by bronchial provocation test were investigated. Partially purified, standardized mould preparations were used in radioallergosorbent test (RAST) with conventional and new update mould discs, mould-induced histamine release and immunoblotting. Updated RAST discs were found to be superior to the old-type discs for the detection of Alternaria but not Cladosporium sensitivity. In all patients except one, specific IgE-antibodies to the respective mould were demonstrated by immunoblotting. Mould-induced histamine release failed to prove sensitization in only two patients. No differences were found comparing histamine release from whole blood with release from isolated cells. The results demonstrate a high sensitivity of in vitro tests when purified and standardized extracts are used.

Allergens↗
PubMed1987

Evidence that parallel Na+-H+ and Cl(-)-HCO3-(OH-) antiporters transport NaCl in the proximal tubule.

The present in vitro microperfusion study examined whether active NaCl transport in the proximal convoluted tubule (PCT) occurs via parallel Na+-H+ and Cl(-)-HCO3-(OH-) exchangers. PCT were perfused with a high-chloride, low-bicarbonate solution simulating late proximal tubular fluid, and were bathed in a similar solution containing 6 g/dl albumin. In this setting the driving forces responsible for passive NaCl transport are eliminated. Addition of 0.1 or 0.5 mM luminal 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS), 0.5 mM luminal 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), or 0.1 mM bath ethoxyzolamide, a lipophilic carbonic anhydrase inhibitor, resulted in an approximately 50% reduction in volume absorption. Inhibition of the Na+-H+ antiporter with 1.0 mM luminal amiloride inhibited volume absorption by 50%. The transepithelial potential difference (PD) was not significantly different from zero, consistent with an electroneutral mechanism for active NaCl transport. The effect of a Cl(-)-HCO3-(OH-) exchanger on acidification was examined in PCT perfused with an ultrafiltrate-like solution and bathed in a serumlike albumin solution. Addition of 0.5 mM DIDS did not significantly decrease volume absorption, demonstrating that luminal DIDS did not result in a nonspecific decrease in solute transport. Luminal DIDS significantly stimulated bicarbonate absorption, consistent with a Na+-H+ antiporter running in parallel with a Cl(-)-HCO3-(OH-) antiporter, which exchanges luminal Cl- for cellular HCO3- (or OH-). In conclusion, these data are consistent with parallel Na+-H+ and Cl(-)-HCO3-(OH-) antiporters mediating neutral active NaCl transport in the PCT.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1987

Insulin stimulates volume absorption in the rabbit proximal convoluted tubule.

The present in vitro microperfusion study examined whether insulin affects volume absorption (Jv) in the proximal convoluted tubule (PCT). PCT were perfused with an ultrafiltrate-like solution and were bathed in a serum-like albumin solution. Addition of a physiologic concentration of 10(-10) M insulin to the bathing solution resulted in a stimulation of Jv and a more negative transepithelial potential difference (PD). There was a progressive stimulation of the lumen negative PD and Jv with higher insulin concentrations. Maximal stimulation occurred at 10(-8) M bath insulin. The insulin-induced stimulation of volume reabsorption was also observed when glucose and amino acids were removed from the luminal perfusate. Direct examination of the effect of insulin on glucose, chloride, and bicarbonate absorption demonstrated that the transport of all these solutes was stimulated by insulin. Addition of insulin to the luminal perfusate had no affect on Jv. These data show that insulin has a direct effect to stimulate Jv in the proximal tubule.

Absorption↗
PubMed1987

Effects of protein kinase C activation on sodium, potassium, chloride, and total CO2 transport in the rabbit cortical collecting tubule.

Several hormones induce phosphatidylinositol turnover in cell membranes and thus activate protein kinase C. Activation of protein kinase C can, in turn, have effects on epithelial transport. These experiments were designed to investigate the effects of two activators of protein kinase C, phorbol 12-myristate,13-acetate (PMA) and L-alpha-1,2-dioctanoylglycerol (L-alpha-1,2-DOG), and two inactive analogues, 4 alpha-phorbol and 4-O-methyl phorbol 12-myristate,13-acetate, on sodium, potassium, chloride, and total CO2 transport in the rabbit cortical collecting tubule. Utilizing in vitro microperfusion techniques, we found that activation of protein kinase C with either PMA or L-alpha-1,2-DOG significantly inhibited net sodium absorption, net potassium secretion and transepithelial voltage in a dose-dependent manner. There was no effect on net chloride or total CO2 transport. In contrast, the inactive phorbol analogues did not alter either sodium or potassium transport. These studies demonstrate that in the rabbit cortical collecting tubule sodium and potassium transport can be inhibited by compounds known to activate proteins kinase C. Thus, hormones that induce phosphatidylinositol turnover in the rabbit cortical collecting tubule may lead to inhibition of sodium transport by activation of protein kinase C.

Animals↗
PubMed1987

Overview of randomized trials of postoperative adjuvant radiotherapy in breast cancer.

An overview of the mortality results of the mature trials in which radiotherapy was a randomized option after simple or radical mastectomy is presented. The principal aim of the overview was to study long-term survival, and recent trials, often including chemotherapy options, have not been included. A total of 7941 patients were entered into these trials and 4148 deaths occurred. No differences were found in survival in the first 10 years of follow-up, in trials employing either radical mastectomy or simple mastectomy. Follow-up information after 10 years came mostly from trials employing radical mastectomy with or without irradiation, and in these trials a significant excess of deaths was observed among patients given radiotherapy (P less than 0.001, all trials; P = 0.002, radical mastectomy trials only). Further data collection will be necessary to determine which causes of death are elevated.

Breast Neoplasms↗
PubMed1986

Effects of breast conservation on psychological morbidity associated with diagnosis and treatment of early breast cancer.

Psychiatric morbidity was assessed in 101 women treated for early breast cancer (T0,1,2,N0,1,M0). Patients had expressed no strong preference for treatment, so were randomised to either mastectomy or breast conservation. The incidence of anxiety states or depressive illness, or both, among women who underwent mastectomy was high (33%) and comparable with that found in other studies. Slightly more of the patients who underwent a lumpectomy followed by radiotherapy had affective disorders, 38% having an anxiety state, depressive illness, or both. These findings question the view that mutilating treatment is predominantly responsible for the measurable psychiatric morbidity reported previously. Counselling services should be provided for all women treated for breast cancer, not just those who undergo mastectomy.

Adult↗
PubMed1986

Butylmaduramycin, a new antibiotic from Actinomadura rubra.

Butylmaduramycin, a new derivative of maduramycin was isolated from the culture medium of a mutant strain of Actinomadura rubra. This communication describes some biological and physico-chemical characteristics of the new antibiotic.

Actinomycetales↗
PubMed1986

Differences in oestrogen receptors in malignant and normal breast tissue as identified by the binding of a new synthetic progestogen.

Oestrogen receptor protein (ER) was detected in 9 of 11 samples of malignant breast tissue and 8 of 9 samples of normal breast tissue. Levels of cytosolic ER (ERc) in malignant breast were 21-1102 fmol mg-1 soluble protein (Kd 1.8 X 10(-9)-3.1 X 10(-8) mol l-1) and those of nucleosolic ER (ERn), 13-526 fmol mg-1 soluble protein (Kd 2.1 X 10(-9)-1.4 X 10(-8) mol l-1). In normal breast tissue ERc levels were 33-640 fmol mg-1 soluble protein (Kd 1.3 X 10(-10)-3.2 X 10(-9) mol l-1), ERn was detected in only 2 samples, 8 and 87 fmol mg-1 soluble protein with Kd 3.2 X 10(-9) and 1.4 X 10(-9) l mol-1 respectively. 17 alpha-ethinyl-13 beta-ethyl-17 beta-hydroxy-4,15-gonadiene-3-one (gestodene), a new synthetic progestogen displaced 3H-oestradiol (3H-E2) from both ERc and ERn in malignant tissue but not in normal breast, or these receptors from endometrial tissue. In competition studies gestodene was approximately 3 times more effective in displacing 3H-E2 from ERc and ERn in malignant breast tissue than the natural ligand. Quantitation of ER by gestodene were ERc, 12-1134 fmol gestodene bound mg-1 soluble protein (Kd 1 X 10(-9)-8.1 X 10(-9) mol l-1); ERn, 17-531 fmol gestodene bound mg-1 soluble protein (Kd 1.6 X 10(-9)-1.1 X 10(-8) mol l-1). L-13-ethyl-17 alpha-ethinyl, 17 beta-hydroxy-gonen-3-one (levonorgestrel) showed no binding to ER in malignant breast, normal breast or endometrial tissue. In circulation both gestodene and levonorgestrel displaced E2 from sex hormone binding globulin more than any of the androgens tested. These results suggest that gestodene is a progestogen with oestrogenic and/or antioestrogenic properties and provide strong evidence for differences in ER from malignant and normal breast tissue.

Binding, Competitive↗