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Biomedical subjects

B Cohen

Publications and source records attributed to B Cohen.

At least 217 records · Page 12Linked to original sources
PubMed1994

A comparative study of peri-prosthetic bone mineral density measurement using two different dual-energy X-ray absorptiometry systems.

24 patients aged 38-72 years with an uncemented total hip arthroplasty had dual-energy X-ray absorptiometry of the upper femur performed at a mean of 27 months after surgery. Each patient was scanned on both Lunar DPX and Hologic QDR-1000 densitometers. Peri-prosthetic bone mineral density (BMD) around the femoral component was measured in seven Gruen zones using software analysis techniques to allow quantification of bone mineral adjacent to a metal implant. There was a high correlation between the results obtained with the two systems (r = 0.94). BMD measurements using the Lunar DPX were 11% higher than with the Hologic QDR; however, there was a lack of agreement between the two instruments indicating that the two methods may not be used interchangeably.

Absorptiometry, Photon↗
PubMed1994

Occupational exposures to Cd, Ni, and Cr modulate titers of antioxidized DNA base autoantibodies.

This study was undertaken to establish whether occupational exposures to derivatives of carcinogenic metals evoke inflammatory immune responses, as determined by the presence of elevated titers of antibodies (Ab) that recognize oxidized DNA bases. Sera obtained from the blood of steel welders (Delaware) and from workers of the Centra Ni-Cd Battery Factory (Poznań, Poland) were analyzed by the enzyme-linked immunosorbent assay. To determine specific and nonspecific binding, an oxidized thymidine [5-hydroxymethyl-2'-deoxyuridine (HMdU)] coupled to bovine serum albumin (HMdU-BSA) as well as mock-coupled BSA (M-BSA) were used as antigens for coating the wells of microtiter plates. Titers of anti-HMdU Ab were significantly elevated in the high Cd and Ni exposure groups (18.3 +/- 3.2 vs 10.8 +/- 2.1 A492/microliters; p < 0.05). The sera of the groups with low exposures to Cd and Ni also had enhanced titers of those Ab but those increases were not statistically significant. Interestingly, the Ab titers present in the sera of controls for Cd and Ni exposures appear to be constant regardless of the protein content. In contrast, both lightly and heavily exposed subjects exhibited Ab titers that increased with increasing protein content. When 12 randomly selected workers (4 from each of the control, lightly, and heavily exposed groups) were outfitted with personal monitors, anti-HMdU Ab titers of those workers showed a significant difference between the groups with light (< 100 micrograms/m3) and heavy (> 200 micrograms/m3) exposures to Cd (9.8 +/- 3.7 vs 22.1 +/- 3.7 A492/microliters; p < 0.01) and Ni (11.7 +/- 1.4 vs 31.0 +/- 1.8; p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Antigen-Antibody Reactions↗
PubMed1994

Isolation and characterization of a soluble form of the LDL receptor, an interferon-induced antiviral protein.

Interferons (IFNs) act by inducing several intracellular antiviral proteins. We report here that IFNs also induce an extracellular soluble protein that inhibits vesicular stomatitis virus (VSV) infection. This protein accounts for 25%-50% of the total antiviral activity elicited by IFN. The antiviral protein was purified to homogeneity from culture supernatants of IFN-treated cells by several chromatographic steps, to give a single 28-kDa active polypeptide. Upon sequencing, this novel protein corresponded to the N-terminal ligand-binding domain of the human 160-kDa low-density lipoprotein receptor (LDLR). In addition, we find that IFN induces the cell surface LDLR and this phenomenon may explain previous reports on reduction of serum cholesterol in IFN-treated patients. Viruses produce soluble cytokine receptors that inhibit their respective cytokines, thereby assisting virus infection. It appears now that host cells employ similar molecules for the opposite role of controlling virus infections.

Amino Acid Sequence↗
PubMed1994

Adopt-A-School Program: recruitment initiative of New York Counties Registered Nurses Association. District 13 education committee.

The goal of this program was to alleviate the existing nursing shortage in New York City by developing recruitment models appropriate for students in the City's high schools. The rationale was that well-informed nurses could create an attractive image of nursing by presenting programs to students, teachers, and guidance counselors. The program was successful in clarifying misconceptions and increasing the knowledge base regarding health issues and concerns and the role of the nurse.

Education, Nursing↗
PubMed1994

Seroprevalence of HIV in orthopaedic patients in Zimbabwe.

The prevalence of HIV infection in East Africa has increased rapidly in recent years. We made a prospective study of the incidence of HIV-seropositivity in patients undergoing orthopaedic procedures in a large district hospital in Bulawayo, Zimbabwe. One of our aims was to determine whether a clinically-based screening programme, derived from the Centre for Disease Control classification of HIV infection, could identify high-risk individuals before surgery. During a 3-month period, 76 patients were tested, and 12 were HIV-positive (16%). Only two of these patients (17%) had clinical features associated with HIV infection; ten (83%) were entirely asymptomatic. Our results indicate that preoperative clinical screening is unlikely to be successful in identifying seropositive patients before routine surgery.

Adolescent↗
PubMed1993

Effectiveness and safety of ofloxacin in chronic otitis media and chronic sinusitis in adult outpatients.

A multicentric study was conducted to evaluate the clinical efficacy and tolerance of ofloxacin in the treatment of chronic sinusitis and chronic otitis (CSOM) in outpatients. Two hundred milligrams of ofloxacin was administered twice a day orally for 12 days in 198 patients with chronic sinusitis and 215 patients with CSOM. Cultures for bacteriology were carried out before treatment. The spectrum of pathogens sensitive to ofloxacin included Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis and Haemophilus influenzae. Higher concentrations of ofloxacin were obtained at sites of infection than in serum. Favorable results were achieved clinically in 93.7% of chronic sinusitis cases and 93.9% of CSOM cases. Adverse effects occurred in only 4.1% of cases. These results support the use of ofloxacin as the drug of first choice in the treatment of chronic sinusitis and CSOM in adult outpatients.

Administration, Oral↗
PubMed1993

The cost-effectiveness of preservation with UW and EC solution for use in cadaveric kidney transplantation in the case of single kidney donors.

University of Wisconsin (UW) solution is now commonly used as a single-flush solution during multiorgan procurement for effective preservation of all intraabdominal organs including the kidney. Many kidneys from single kidney donors are still preserved in Eurocollins solution and the question is whether preservation in UW solution is more cost-effective. A European randomized multicenter trial was organized by the Department of Surgery of Leiden University in close cooperation with Eurotransplant to study the efficacy of UW solution as compared with EC solution. On the basis of this trial we found that at three months after transplant 92.4% of the patients in the UW group had a functioning graft in comparison with 88.4% in the EC group (similar figures after one year were 88.2% and 82.5%, P approximately 0.04), while health care expenditure during these first three months was on average US$ 700 lower for the UW group than for the EC group, taking into account the price difference in the preservation fluids. The long-term benefits of using UW solution as compared with EC solution were conservatively estimated at US$ 7000 per patient reflecting the additional expenses for dialysis in the EC group. We concluded that the extra costs of using UW solution instead of EC solution (US$ 230 per kidney) can be easily earned back within three months and that the long-term savings of such a strategy are considerable. Moreover, the health status of patients in the UW group is expected to be better on the average than in the EC group. Simply reacting to the price tag of the UW solution may be penny-wise but pound-foolish.

Adenosine↗
PubMed1993

Formation, absorption, and biotransformation of delta 6-lithocholenic acid in humans.

delta 6-Lithocholenic acid was identified in small amounts in fecal samples in vitro after incubation with ursodeoxycholic acid and in vivo in controls and after chenodeoxycholic and ursodeoxycholic acid ingestion. Fourteen to 45.0% of delta 6-[24-14C]lithocholenic acid was biotransformed in vitro in feces within 30 s. After colonic instillation of delta 6-[24-14C]lithocholenic acid, 50% of the radioactivity appeared in bile acids, most of it in lithocholic acid, within 3 h. Jejunal perfusions with delta 6-[24-14C]lithocholenic acid showed 33-92% absorption. One hour after jejunal instillation of 1 mmol, 4.4-27.5% of the biliary radioactivity was found in ursodeoxycholic, chenodeoxycholic, lithocholic, and 7-ketolithocholic acids. A sulfated glycine conjugate of delta 6-lithocholenic acid was identified in bile. One hour after intravenous injection of delta 6-[24-14C]lithocholenic acid, 40.1-42.6% of biliary radioactivity appeared in 7-ketolithocholic, chenodeoxycholic, lithocholic/isolithocholic, and ursodeoxycholic acids. The studies show that delta 6-lithocholenic acid is 1) formed in colonic lumen from chenodeoxycholic and ursodeoxycholic acids, 2) well absorbed in small intestine, and 3) biotransformed in both the colonic lumen and liver. The studies also identified delta 6-lithocholenic acid as a new intermediate in formation of lithocholic acid. Finally, the studies showed that a small portion of delta 6-lithocholenic acid is excreted as a sulfated glycine conjugate in bile.

Bile↗
PubMed1993

Allocation of the thoracic imaginal primordia in the Drosophila embryo.

The primordia of the thoracic imaginal discs of the Drosophila embryo originate as groups of cells spanning the parasegment boundary. We present evidence that the thoracic imaginal primordia are allocated in response to signals from the wingless (wg) and decapentaplegic (dpp) gene products. Rows of cells that express wg intersect rows of cells that express dpp to form a ladder-like pattern in the ectoderm of the germ band extended embryo. The imaginal primordia originate as groups of cells which lie near these intersection points. We have used a molecular probe derived from the Distal-less (Dll) gene to show that this population contains progenitor cells for both the dorsal (i.e. wing) and ventral (i.e. leg) discs. Although we show that Dll function is not required for allocation of imaginal cells, activation of an early Dll enhancer may serve as a molecular marker for allocation. A group of cells, which includes the imaginal progenitors, activate this enhancer in response to intercellular signals from wg and perhaps from dpp. We have used a conditional allele of wg to show that wg function is transiently required for both allocation of the imaginal primordia and for initiation of Dll expression in these cells during the brief interval when wg and dpp form the ladder-like pattern. Allocation of the imaginal primordium and activation of Dll expression appear to be parallel responses to a single set of positional cues.

Animals↗
PubMed1993

Distal-less is a downstream gene of Deformed required for ventral maxillary identity.

The homeotic selector (HOM) proteins are required for the diversification of the anterior-posterior axis of the Drosophila body plan, assigning unique identities to regional domains of cells comprising one or a few parasegments or segments. The HOM proteins apparently accomplish this task by the transcriptional regulation of numerous downstream genes. At present few downstream genes are known, so models of how downstream genes mediate HOM functions are based more on intuition than information. Our results indicate that Distal-less is a downstream gene of the HOM gene Deformed, and Distal-less function is required for the elaboration of a subset of the maxillary epidermal identities specified by Deformed. The regulatory effect of Deformed on Distal-less is mediated by a ventral maxillary-specific enhancer located 3' of the Distal-less transcription unit. We propose that Deformed and Distal-less, both of which encode homeodomain transcription factors that are persistently expressed in ventral maxillary cells, combinatorially specify a subsegmental code required for a group of cells to differentiate maxillary cirri.

Animals↗
PubMed1993

Radiation exposure to the hands of orthopaedic surgeons during procedures under fluoroscopic X-ray control.

The hands of the surgeon are most likely to be directly exposed to ionizing radiation during fluoroscopic screening in the orthopaedic theatre. There is however little information available on the level of exposure to radiation during the normal working pattern of individual surgeons. The purpose of this study was to directly measure the radiation exposure to the hands during fluoroscopic screening in a series of consecutive cases over a month in order to establish whether these staff need to be designated classified persons, and if not, whether they need to be routinely monitored. Extremity monitoring was carried out using thermoluminescent dosimeters. The dosimeter was secured to the operating surgeon's dominant index finger. 44 procedures were carried out by nine different surgeons. The total radiation dose received per surgeon ranged from 48-2329 microSv. In 80% of procedures the dose of radiation to the surgeon's hand was less than 100 microSv. The extrapolated annual dose, even for the surgeon with the highest radiation exposure, was well below the annual dose limit for extremities of 500 mSv per year recommended by the International Commission on Radiological Protection, and embodied in the Ionizing Radiations Regulations 1985. Despite the relatively low doses of radiation received by surgeons in this study, occupational exposure to all personnel should be kept to the lowest practicable levels, and a review of procedures, including dose measurements, from time to time is advised.

Fingers↗
PubMed1993

The effect of pulmonary impairment on all-cause mortality in a national cohort.

The association between pulmonary impairment and all-cause mortality was investigated among white subjects in a follow-up study of a large national cohort. Pulmonary function was measured during the National Health and Nutrition Examination Survey (NHANESI) (1971 to 1975); subsequent mortality information was obtained from the 1987 NHANES I Epidemiologic Follow-up Study (1982 to 1987). Of 4,764 white sample persons, ages 25 to 74 years examined during NHANES I, 658 (13.8 percent) were identified as having pulmonary impairment defined as a FEV1/FVC < or = 69 percent. A total of 743 (15.6 percent) sample persons died during the follow-up period. The association between pulmonary impairment and all-cause mortality was examined for male and female subjects separately using the Cox proportional hazards model controlling for age, smoking, educational level, body mass index, and respiratory diseases. The analysis suggests that reduced FEV1 percent predicted was a significant risk factor for mortality among both sexes, and the FEV1/FVC ratio was significantly associated with all-cause mortality among male subjects only.

Adult↗
PubMed1993

[Conservative trans-mandibular lateral pharyngectomy. Functional results in a series of 38 patients].

The authors present their experience with conservative transmandibular lateral pharyngectomy used for access to oropharyngeal tumours of the buccal cavity. This study was conducted to evaluate both early results and later aesthetic and functional sequelae after a simplified operation using mini-plaques. This surgical route was used for 38 patients since 1985, including 9 for salvage operations. Surgical indications were tumours of the posterior wall of the pharynx (28), the posterior part of the tongue (8), the retromolar tigone (1), the intramaxillary commissure (2) and the pelvi-lingual region (2). Access via the mandibulotomy was always evaluated peroperatively on the basis of the cleavability of the periosteum of the medial mandibular table. Immediate follow-up was uneventful in 74% cases. Post-operative complications included two general decompensations due to the original lesion, four minor local complications (spontaneous by regressive non-unions) and four local complications requiring a second intervention (flap necrosis, 2; orostomy, 2). Five of the complications were directly related to the mandibulotomy, giving an overall rate of 13%; the rates for first intention and salvage surgery were 9% and 18% respectively. Functional capacity was considered excellent in 75% of the cases and the aesthetic results were good in 94%. The satisfactory post-operative course, the low rate of major complications both after first intention and salvage surgery, and the excellent functional and aesthetic results suggest that transmandibular bucco-pharyngectomy should be preferred whenever the state of the cancerous lesion does not require exeresis of the ramus.

Adult↗
PubMed1992

Soluble interferon-alpha receptor molecules are present in body fluids.

Soluble forms of the interferon-alpha receptor (sIFN-alpha R) were identified in human serum and urine by Western blotting with monoclonal antibodies (MAb) directed against IFN-alpha R, and by immunoprecipitation (Iptn) of a covalently cross-linked complex of IFN-alpha R and [125I]IFN-alpha with anti IFN-alpha MAb. Elevated levels of sIFN-alpha R were found in sera of hairy cell leukemia patients. The soluble receptor from serum migrated as a 55 kDa protein in SDS-PAGE, and, as expected, the cross-linked product migrated as a 75 kDa protein. The soluble receptor from urine was found to be a protein of mol. wt. 45 kDa and its cross-linked complex migrated as a 65 kDa protein. The calculated mol. wt. of the entire extracellular domain of the IFN-alpha R prior to post-translational modifications is 47,000. Since there are 12 potential glycosylation points in this extracellular domain, its actual mol. wt. may be as high as 70,000 Da. It is therefore concluded that sIFN-alpha R molecules, corresponding to truncated forms of the extracellular domain of the cell surface IFN-alpha R, are present in human serum and in normal human urine.

Animals↗
PubMed1992

Homeotic genes of the Bithorax complex repress limb development in the abdomen of the Drosophila embryo through the target gene Distal-less.

Homeotic genes encode transcription factors that are thought to specify segmental identity by regulating expression of subordinate genes. Limb development is repressed in the abdominal segments of the Drosophila embryo by the hometic genes of the Bithorax complex (BX-C). Localized expression of the homeobox gene Distal-less (DII) is required for leg development in thoracic segments. We have identified a minimal cis-regulatory enhancer element that directs DII expression in the larval leg primordia. We present evidence that the BX-C proteins repress DII expression in abdominal segments by binding to a small number of specific sites in this element. Mutating these sites eliminates BX-C protein binding and renders the element insensitive to BX-C-mediated repression in vivo. Repression of limb development in the abdomen appears to be controlled at the DII enhancer. Thus DII may serve as a downstream target gene through which the homeotic genes control abdominal segment identity in the Drosophila embryo.

Amino Acid Sequence↗