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Biomedical subjects

J Borkowski

Publications and source records attributed to J Borkowski.

At least 19 recordsLinked to original sources
PubMed2001

Soluble selectin profiles associated with severe trauma.

Severe trauma acts as a trigger for the complex cascade of postinjury events leading to the release of different mediators and the development of generalized inflammation. Selectins are a family of adhesion proteins that are responsible for the adherence of polymorphonuclear neutrophils to the endothelium. This interaction plays an important role in the development of severe complications after multiple trauma. The aim of the present study is to follow the sequential alterations in circulating selectin levels after severe injury and to evaluate the clinical significance of these mediators in monitoring prognosis and outcome. Thirty four severely traumatized patients were entered into the study. Serum sE-selectin, plasma sP-selectin and sL-selectin concentrations were measured and an APACHE II score was calculated on admission to the intensive care unit and during the subsequent 5 days. The patients were divided into survivors and nonsurvivors. Initial soluble P- and E-selectin concentrations were significantly elevated in all trauma patients. The highest values of these adhesion molecules were measured in all the observed days in patients with poor prognosis and outcome. In survivors we found a systematic decrease in the sP-selectin concentrations. On admission, the sL-selectin concentrations in all trauma patients were decreased. There were stable, very low values in nonsurvivors and a slow increase in circulating L-selectin in patients who survived. The pattern of soluble selectins in patients with severe trauma is characterized by increased levels of P- and E-selectin and a decreased concentration of L-selectin. These findings suggest a widespread microvascular endothelial activation on injury in the early posttraumatic period, which may be associated with increased neutrophil-endothelial adhesion, neutrophil extravasation and migration. We suppose that these parameters of endothelial cell activation/injury may be useful as another early prognostic factor in severe trauma.

Adult↗
PubMed2000

Steam sterilizable probes for dissolved oxygen measurement. Reprinted from Biotechnology and Bioengineering, Vol. VI, Issue 4, Pages 457-468 (1964).

Steam-sterilizable membrane probes for monitoring the dissolved oxygen level in fermentors, or the oxygen content of gas streams, are described. The probes have a silver cathode, a lead anode, and an acetate buffer as an electrolyte. The membrane is Teflon. The current output of the probes in the absence of oxygen is negligible.

Equipment Design↗
PubMed2000

Fine-needle aspiration cytology of hemangiopericytoma: report of two cases.

The fine-needle aspiration biopsy (FNAB) findings in two cases of hemangiopericytoma (HP), arising in the parotid gland and on the inner chest wall, respectively, are reported. Smear preparations in each case showed cytologic features of an undifferentiated spindle-cell neoplasm, whereas a core needle biopsy specimen of the chest wall mass showed a spindle-cell tumor with a "staghorn-like" arrangement of endothelium-lined vascular channels. Immunostains performed on this core biopsy, and on the surgical resection specimens in both cases, showed positive staining of tumor cells for vimentin and CD34, with negative staining for a variety of smooth muscle, epithelial, neural, and neuroendocrine markers. Electron microscopy performed in one case further supported the diagnosis of HP. With adequate sampling and appropriate use of ancillary studies, a diagnosis of HP can be reliably suggested on the basis of FNAB and core biopsy of a soft-tissue mass.

Aged↗
PubMed2000

Fulminant parvovirus infection following erythropoietin treatment in a patient with acquired immunodeficiency syndrome.

We report the case of a 41-year-old black man with acquired immunodeficiency syndrome who developed a severe chronic anemia due to parvovirus infection. Bone marrow biopsy revealed erythroid aplasia. The infectious nature of the anemia was not recognized, and the patient was treated with erythropoietin. The patient's reticulocyte response was inadequate, however, and he remained anemic. A second bone marrow biopsy showed erythroid hyperplasia and prominent intranuclear parvovirus inclusions within erythroid progenitors. Erythropoietin was discontinued and was followed by a course of intravenous immunoglobulin, which resulted in rapid correction of anemia. To our knowledge, this is the first reported case of fulminant human parvovirus infection exacerbated by erythropoietin administration and documented by sequential bone marrow histologic examination. This case illustrates the critical importance of considering parvovirus in the etiology of chronic anemia with erythroid aplasia in immunocompromised patients.

AIDS-Related Opportunistic Infections↗
PubMed1998

Cloning and characterization of a new subtype of thyrotropin-releasing hormone receptors.

A new subfamily member of thyrotropin releasing hormone (TRH) receptor gene, TRHR2, was isolated from rat brain cDNAs. The deduced amino acid sequence of TRHR2 is 51 % identical to that of rat TRH receptor gene which was reported previously. Northern blot analysis with TRHR2 probe revealed brain-specific expression of a 9.5 kb mRNA. In a binding experiment using the TRHR2-expressing COS cells, specific binding of TRH to TRHR2 was observed with Kd value of 9 nM which was equivalent to the Kd value (= 13 nM) of TRH binding to the TRH receptor previously reported. The active metabolite of TRH, histidyl-proline diketopiperazine, or cyclo(His-Pro), showed no specific binding activity. These results suggest that TRHR2 is a novel subtype of TRH receptor.

Amino Acid Sequence↗
PubMed1997

Purification and characterization of a kinase-associated, myofibrillar smooth muscle myosin light chain phosphatase possessing a calmodulin-targeting subunit.

A myofibrillar form of smooth muscle myosin light chain phosphatase (MLCPase) was purified from turkey gizzard myofibrils, and it was found to be closely associated with the myosin light chain kinase (MLCKase). For this reason we have named this phosphatase the kinase- and myosin-associated protein phosphatase (KAMPPase). Subunits of the KAMPPase could be identified during the first ion exchange chromatography step. After further purification on calmodulin (CaM) and on thiophosphorylated regulatory myosin light chain affinity columns we obtained either a homogenous preparation of a 37-kDa catalytic (PC) subunit or a mixture of the PC subunit and variable amounts of a 67-kDa targeting (PT) subunit. The PT subunit bound the PC subunit to CaM affinity columns in a Ca2+-independent manner; thus, elution of the subunits required only high salt concentration. Specificity of interaction between these subunits was shown by the following observations: 1) activity of isolated PC subunit, but not of the PTC holoenzyme, was stimulated 10-20-fold after preincubation with 5-50 microM of CoCl2; 2) the pH activity profile of the PC subunit was modified by the PT subunit (the specific activity of the PTC holoenzyme was higher at neutral pH and lower at alkaline pH); and 3) affinity of the holoenzyme for unphosphorylated myosin was 3-fold higher, and for phosphorylated myosin it was 2-fold lower, in comparison with that of the purified PC subunit. KAMPPase was inhibited by okadaic acid (Ki = 250 nM), microcystin-LR (50 nM) and calyculin A (1.5 microM) but not by arachidonic acid or the heat-stable inhibitor (I-2), which suggested that this is a type PP1 or PP2A protein phosphatase.

Animals↗
PubMed1997

Purification and characterization of a smooth muscle myosin light chain kinase-phosphatase complex.

We show that a myofibrillar form of smooth muscle myosin light chain phosphatase (MLCPase) forms a multienzyme complex with myosin light chain kinase (MLCKase). The stability of the complex was indicated by the copurification of MLCKase and MLCPase activities through multiple steps that included myofibril preparation, gel filtration chromatography, cation (SP-Sepharose BB) and anion (Q-Sepharose FF) exchange chromatography, and affinity purification on calmodulin and on thiophosphorylated regulatory light chain columns. In addition, the purified complex eluted as a single peak from a final gel filtration column in the presence of calmodulin (CaM). Because a similar MLCPase is present in varying amounts in standard preparations of both MLCKase and myosin filaments, we have named it a kinase- and myosin-associated protein phosphatase (KAMPPase). The KAMPPase multienzyme complex was composed of a 37-kDa catalytic (PC) subunit, a 67-kDa targeting (PT) subunit, and MLCKase with or without CaM. The approximate molar ratio of the PC and PT subunits was 1:2 with a variable and usually higher molar content of MLCKase. The targeting role of the PT subunit was directly demonstrated in binding experiments in which the PT subunit bound to both the kinase and to CaM. Its binding to CaM was, however, Ca2+-independent. MLCKase and the PT subunit potentiated activity of the PC subunit when intact myosin was used as the substrate. These data indicated that there is a Ca2+-independent interaction among the MLCPase, MLCKase, and CaM that are involved in the regulation of phosphatase activity.

Animals↗
PubMed1996

The memory-facilitating effects of the competitive NMDA-receptor antagonist CGP 37849 are steroid-sensitive, whereas its memory-impairing effects are not.

The retention performance of mice in a passive-avoidance task was facilitated by low doses (0.3 mg/kg) of the competitive NMDA-receptor blocker CGP 37849, but impaired by high doses (30 mg/kg). The facilitatory effect was selectively suppressed by elevation of the plasma levels of aldosterone or corticosterone, or by blockade of steroid biosynthesis or the mineralocorticoid receptors. The impairment of memory, on the other hand, was not steroid sensitive. Accordingly, the data are in line with the hypothesis that drug induced memory facilitation is dependent on steroid sensitive processes.

2-Amino-5-phosphonovalerate↗
PubMed1996

The GABAB receptor antagonist CGP 36,742 and the nootropic oxiracetam facilitate the formation of long-term memory.

The memory-enhancing effects of a single treatment with the GABAB antagonist CGP 36,742 (10 mg/kg) or the nootropic agent oxiracetam (100 mg/kg) given immediately after a learning experience ('post-trial') remain detectable for at least 4 months thereafter. This indicates that in all probability these substances facilitate the formation of the long-term memory trace.

Animals↗
PubMed1994

Delayed emergence of effects of memory-enhancing drugs: implications for the dynamics of long-term memory.

Many theories of memory postulate that processing of information outlasts the learning situation and involves several different physiological substrates. If such physiologically distinct mechanisms or stages of memory do in fact exist, they should be differentially affected by particular experimental manipulations. Accordingly, a selective improvement of the processes underlying short-term memory should be detectable only while the information is encoded in the short-term mode, and a selective influence on long-term memory should be detectable only from the moment when memory is based on the long-term trace. Our comparative study of the time course of the effects of the cholinergic agonist arecoline, the gamma-aminobutyric acid type B receptor antagonist CGP 36742, the angiotensin-converting enzyme inhibitor captopril, and the nootropic oxiracetam, four substances with completely different primary sites of action, show that the memory-enhancing effects consistently come into evidence no sooner than 16-24 h after the learning trial. On the one hand, this finding suggests that all these substances act by way of the same type of mechanism; on the other hand, it demonstrates that the substrate modulated by the compounds forms the basis of memory only after 16-24 h. From the observation that animals also show clear signs of retention during the first 16 h--i.e., before the effects of the substances are measurable--it can be inferred that retention during this time is mediated by other mechanisms that are not influenced by any of the substances.

Animals↗
PubMed1993

Inner-city pharmacies: can they meet the OBRA '90 mandates?

Visits were made to 21 pharmacies in two poor Chicago neighborhoods as one component of the University of Illinois at Chicago's commitment to help improve health care delivery, ensure that pharmacy services are not overlooked in local health reform efforts, and understand the implications of the Omnibus Budget Reconciliation Act of 1990 (OBRA '90). Pharmacists report that Medicaid reimbursement policies result in: (1) prescribing patterns that have no consistent therapeutic or economic rationale; (2) dispensing of expensive drugs, some of which are then sold on the street or to other pharmacies; and (3) dispensing of unnecessary and often expensive legend drugs when other legend drugs and generics or over-the-counter products would perform just as well. On the positive side, 76% of the pharmacies possess computerized patient-profile systems, and 72% maintain background information on their prescribers. These results suggest that OBRA '90's mandates should contribute toward improving the Medicaid program, but that implementation is likely to be difficult and uneven.

Chicago↗
PubMed1993

Urethral stricture repair: results in 179 patients.

From 1977 till April 1990 169 operative reconstructions of urethral strictures were carried out in this clinic. 49 patients with a short stricture (less than 2 cm) underwent excision and end to end anastomosis. In 18 patients with a long stricture (2-6 cm) one stage urethroplasty with a transverse distal penile or preputial island of skin flap was used. 102 patients with extensive or otherwise problematic strictures were subjected to two-stage mesh skin graft urethroplasty. In 10 patients with a short stricture we have recently implanted a new urethral stent in the strictured area after visual urethrotomy. During a long-time follow-up a good anatomical and functional result was achieved in all but 2 patients who underwent an excision and end to end anastomosis. In the island flap urethroplasty group a restricture occurred in one patient, and mesh graft urethroplasty was successful in all but 3 patients. In the urethral stent patients the primary results are excellent.

Adolescent↗
PubMed1992

Pretreatment with aldosterone or corticosterone blocks the memory-enhancing effects of nimodipine, captopril, CGP 37,849, and strychnine in mice.

Oral pretreatment with aldosterone or corticosterone blocked the memory-enhancing effects of the calcium antagonist nimodipine, the ACE inhibitor captopril, the NMDA blocker CGP 37,849, and the glycine antagonist strychnine in a passive-avoidance test in mice. The memory-disturbing effects of phenobarbitone, diazepam, CGP 37,849 and scopolamine were not influenced by the hormonal pretreatment. These findings could indicate the involvement of a steroid-sensitive mechanism in drug-induced improvement of memory. In the light of clinical observations showing elevated cortisol levels in Alzheimer patients, the results might also explain why only a limited number of these patients respond to therapy with memory enhancers.

2-Amino-5-phosphonovalerate↗