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Biomedical subjects

D Becker

Publications and source records attributed to D Becker.

At least 271 records · Page 15Linked to original sources
PubMed1988

Effect of chronic haloperidol treatment on peripheral benzodiazepine binding sites in cerebral cortex of rats.

The effects of 21 days of haloperidol treatment on central benzodiazepine (BZ) receptors in the cerebral cortex of rats and on peripheral-type BZ binding sites (PBS) in the cerebral cortex and heart of rats were studied. Neuroleptic treatment did not affect the maximal binding capacity or the affinity of the central BZ receptor to 3H-flunitrazepam. Chronic haloperidol treatment resulted in a significant increase of 38% in PBS density in the cerebral cortex, with no alteration in PBS density in the heart. No alteration in PBS affinity for its ligand 3H-PK 11195 was observed, either in the cerebral cortex or in the heart. The modulatory effect of chronic haloperidol administration on PBS density in the brain may be related to some of the neurobehavioral or hormonal effects of the drug.

Animals↗
PubMed1988

An ESR investigation of the reactions of glutathione, cysteine and penicillamine thiyl radicals: competitive formation of RSO., R., RSSR-., and RSS(.).

The reactions of the cysteine, glutathione and penicillamine thiyl radicals with oxygen and their parent thiols in frozen aqueous solutions have been elucidated through electron spin resonance spectroscopy. The major sulfur radicals observed are: (1) thiyl radicals, RS.; (2) disulfide radical anions. RSSR-.; (3) perthiyl radicals, RSS. and upon introduction of oxygen; (4) sulfinyl radicals, RSO., where R represents the remainder of the cysteine, glutathione or penicillamine moiety. The radical product observed depends on the pH, concentration of thiol, and presence or absence of molecular oxygen. We find that the sulfinyl radical is a ubiquitous intermediate in the free radical chemistry of these important biological compounds, and also show that peroxyl radical attack on thiols may lead to sulfinyl radicals. We elaborate the observed reaction sequences that lead to sulfinyl radicals, and, using 17O isotopic substitution studies, demonstrate that the oxygen atom in sulfinyl radicals originates from dissolved molecular oxygen. In addition, the glutathione thiyl radical is found to abstract hydrogen from the alpha-carbon position on the cysteine residue of glutathione to form a carbon-centered radical.

Chemical Phenomena↗
PubMed1988

Growth and phenotypic characteristics of human nevus cells in culture.

Nevus cells were isolated from the three cutaneous components, epidermis, basal layer, and dermis, of nonmalignant pigmented lesions and were cultured separately in the presence or absence of the phorbol ester 12-0-tetradecanoyl phorbol-13-acetate in medium that supports the rapid proliferation of melanocytic cells. The separation procedure used provided cultures that were essentially free from normal melanocytes (dermis) or fibroblasts (epidermis). In short term culture, nevus cells of all skin compartments expressed markers associated with differentiated melanocytes, such as presence of premelanosomes and melanosomes and elevated tyrosinase levels. Nevus cells also expressed melanoma-associated antigens, such as NGF-receptor, transferrin-related p97, proteoglycan, and HLA-DR as detected with monoclonal antibodies. After several subpassages, cells showed a decreased expression of melanoma-associated antigens, decreased tyrrosinase levels, and melanosomes could no longer be detected. Morphologically, these cells were similar to fibroblasts. The disappearance of melanoma-associated cell surface antigens was concomitant with the appearance of a melanocyte-associated 145 kd protein that might serve as a marker of fibroblast-like differentiation in nevus cells and normal melanocytes. Nevus cell cultures grown in the presence of 12-0-tetradecanoyl phorbol-13-acetate maintained a stable differentiated phenotype throughout their lifespan. As reported earlier, nevus cells in culture, irrespective of the presence or absence of 12-0-tetradecanoyl phorbol-13-acetate, have a finite lifespan in vitro, grow anchorage-independent in soft agar, but do not form tumors when xenografted to nude mice. These studies demonstrate that nevus cells isolated from the epidermal, basal layer, and dermal components of lesional skin can serve as models to characterize the initial steps of tumor progression in a human cell system.

Adolescent↗
PubMed1988

Intraoperative development of contralateral epidural hematoma during evacuation of traumatic extraaxial hematoma.

Intraoperative development of an epidural hematoma contralateral to a craniotomy for acute traumatic extraaxial hematoma has been previously reported. This entity, however, has never been distinctly defined and differentiated from either the delayed or the bilateral acute epidural hematoma. We present 3 new cases of intraoperative contralateral acute epidural hematoma and review the 14 previously reported cases. The typical clinical presentation is a severe head injury with an acute extraaxial hematoma and severe ipsilateral brain displacement during craniotomy. If brain displacement is not noted at craniotomy, then the contralateral hematoma is manifested by immediate postoperative neurological deterioration or intractable elevated intracranial pressure. The presence of any of these signs makes an immediate postoperative CT scan or burr holes contralateral to the original craniotomy mandatory for early diagnosis. In addition to defining "intraoperative contralateral epidural hematoma," stricter definitions of the terms "delayed epidural hematoma" (no hematoma present on the initial CT scan but one present on a later scan) and "bilateral epidural hematomas" (present on the initial scan) are proposed.

Adolescent↗
PubMed1988

[A sparing operation in fracture of the radius head using pinning with resorbable Biofix material].

The incidence of dislocated, subcapitular radial head fracture is discussed. The traditional treatment of this fracture dictates resection of the radial head which induces disturbances of the elbow and wrist. The author has used the bio-degradable material BIOFIX as a 4.5 mm thick pin for internal splinting of the fracture. Early mobilization is possible and later no metal has to be removed. By demonstrating one case of treatment by BIOFIX the author shows a new chance for conservation of the radial head and thereby of the function of the joints.

Adult↗
PubMed1987

Sulfinyl radical formation from the reaction of cysteine and glutathione thiyl radicals with molecular oxygen.

Using Electron Spin Resonance spectroscopy at low temperatures, we find that thiyl radicals resulting from irradiation of frozen aqueous solutions of a variety of thiols, including cysteine, glutathione, and penicillamine react with oxygen to form sulfinyl (RSO.) radicals. The identity of the cysteine sulfinyl radical has been confirmed by the use of molecular oxygen isotopically labeled with 17O. Previous workers have suggested the reaction of thiyl radicals and molecular oxygen resulted in the formation of the potentially damaging thiol peroxyl radical, RSOO.; our work shows no evidence for this species. The sulfinyl radicals are suggested to result from a direct reaction between thiyl radicals and molecular oxygen. This reaction results in the cleavage of the dioxygen bond.

Cysteine↗
PubMed1987

The effect of fibronectin therapy and fibronectin deficiency on healing of rat burns and excision wounds.

Rats with standardized burns and skin excision wounds were treated i.p. with human fibronectin or swine skin gelatin. Controls received bovine albumin, solvent, or no treatment. Wound healing was assessed by planimetry, additionally plasma fibronectin was determined. Solvent or albumin did not influence the healing process, neither did fibronectin. However, when opsonizing fibronectin was additionally consumed by application of gelatin, a significant retardation of wound healing was observed. The results support the opinion that fibronectin is of essential importance for posttraumatic opsonization of gelatin-like material originating from the damaged tissue.

Animals↗
PubMed1987

Effect of fibronectin therapy and fibronectin deficiency on wound healing: a study in rats.

Rats with standardized 3rd-degree burns of 1% body surface were treated intraperitoneally with different doses of human fibronectin or swine gelatin immediately after injury and on the following days. Controls received bovine albumin or no further treatment. Wound healing was assessed by planimetry (days 0, 2, and 7); additionally, plasma fibronectin was determined (days 3 and 7). On day 3 fibronectin levels were significantly elevated after albumin and the highest dosage of fibronectin (3 X 16 mg) and decreased after gelatin and the lowest dosage of fibronectin (3 X 4 mg). Wound healing was neither affected by albumin nor by human fibronectin, but it was significantly impaired by gelatin-induced lack of fibronectin. The data support the opinion that fibronectin is an essential factor for the post-traumatic clearance of gelatin-like tissue debris via the reticuloendothelial system (RES). Overload by gelatin results in fibronectin deficiency and RES dysfunction with risks of infection and poor wound healing.

Animals↗
PubMed1987

Long-term effects of modest weight loss in type II diabetic patients.

Since most obese patients with type II diabetes are unable to achieve ideal body weight, this study examined whether more modest weight losses would provide a long-term benefit. Type II diabetic patients (N = 114) were treated in a behavioral weight control program and followed up for one year. Weight loss was significantly correlated with improvements in glycosylated hemoglobin values at posttreatment (r = .55) and one year (r = .51). Patients who lost more than 6.9 kg or had more than 5% reduction in body weight had significant improvements in glycosylated hemoglobin values at one year, while patients losing less weight had nonsignificant changes and those gaining weight had significant worsening. Thus, modest weight loss can have a long-term impact on glycemic control. However, the improvement in glycemic control for a given weight loss was greater initially than at one year, suggesting that energy restriction, in addition to weight loss, may contribute to initial improvement. Neither percent overweight nor diabetes treatment affected weight loss.

Adult↗
PubMed1987

[From phonocardiography to phonoanalysis].

We report on a new system for the examination and presentation of heart sounds, the phonoanalysis (PHA). It gives automatically a complete, objective physically founded picture of heart sounds and murmurs by registering the frequency spectrum graphically, as well as presenting in a numeric format, as a whole and as a function of time; in addition, the usual phonocardiographic and electrocardiographic leads may be obtained. A further function is to measure--probably for the first time--quantitatively the "roughness" of heart murmurs. This factor is also essential for the quality of murmurs and independent of the pitch. Therefore, the quantitative assessment of roughness has been proposed as an essential part of the physically founded description of heart murmurs in the auscultation, in addition to the determination of the dominating frequency (pitch). The term 'roughness' should not been confined to the extremely rough low-pitched heart murmurs e.g. in typical aortic stenosis. The PHA gives a better insight into the hemodynamic basis of heart murmurs and discloses properties of murmurs not recognized by auscultation and phonocardiography. The PHA can also be used for the examination of vascular, lung, bronchial and abdominal murmurs and also in connection with a stethoscope using an airborne sound microphone.

Computers↗
PubMed1986

Comparison of nonwoven and woven gown and drape fabric to prevent intraoperative wound contamination and postoperative infection.

In a prospective, controlled clinical trial, nonwoven, disposable gown and drape fabrics were no better barriers to intraoperative wound contamination or postoperative wound infection than reusable cotton poplin. We observed no difference between the two study groups in either the frequency or level of intraoperative wound contamination as judged by cultures of specimens collected at the time of wound closure. Of procedures in which reusable fabrics were used, 13.1 percent had positive cultures compared with 15.5 percent of those in which disposable fabrics were used (difference not statistically significant). We recovered coagulase-negative Staphylococci from more than 95 percent of contaminated wounds. Rates of postoperative wound infection were virtually identical in the two groups. Our data suggest that either both fabrics were similar in their ability to block bacteria that were shed from skin surfaces from entering the wound, or that bacteria which contaminate the wound in clean surgical procedures are derived from sources other than skin.

Clinical Trials as Topic↗
PubMed1986

Postcholecystectomy wound infection. The impact of prophylactic antibiotics on the epidemiology of infections.

The clinical courses of 347 patients undergoing gallbladder surgeries were monitored to study the epidemiology of postcholecystectomy wound infection in a hospital in which high-risk patients received prophylactic antibiotics. Overall, 3.8% of patients had wound infections. Patients who had positive bile cultures taken during surgery or positive intraoperative wound cultures had higher rates of infection than patients with negative cultures. However, there was a poor correlation among the bacterial isolates that were recovered from the bile or the wound surface during surgery and from postoperative infections. Antibiotic-sensitive enteric bacteria were recovered from bile samples at surgery, gram-positive organisms and enteric gram-negative bacteria were isolated from intraoperative cultures of the wound surface, and antibiotic-resistant gram-negative bacteria or enterococci were recovered from wounds that developed postoperative infections. There was a strong association between the prior receipt of prophylactic antibiotics and infections with antibiotic-resistant bacteria. Data suggest that bactibilia is still an important epidemiologic marker that identifies patients at high risk for subsequent wound infection. However, in patients who have received prophylactic antibiotics, intraoperative cultures cannot be relied on to guide the choice of empiric therapeutic antibiotics for postoperative infections. Bacteria responsible for these infections are not identified by cultures taken at the time of surgery and are often resistant to the class of antibiotics used for prophylaxis.

Adolescent↗