Proper use of the waist to hip ratio.
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Anthropometry↗
Biomedical subjects
H Alexander
Publications and source records attributed to H Alexander.
Altering the antigenicity of proteins.
To better understand the binding interaction between antigen and antibody we need to distinguish protein residues critical to the binding energy and mechanism from residues merely localized in the interface. By analyzing the binding of monoclonal antibodies to recombinant wild-type and mutant myohemerythrin (MHr) proteins, we were able to test the role of individual critical residues at the highly antigenic site MHr-(79-84), within the context of the folded protein. The results directly show the existence of antigenically critical residues, whose mutations significantly reduce antibody binding to the folded protein, thus verifying peptide-based assignments of these critical residues and demonstrating the ability of buried side chains to influence antigenicity. Taken together, these results (i) distinguish the antigenic surface from the solvent-exposed protein surface before binding, (ii) support a two-stage interaction mechanism allowing inducible changes in protein antigens by antibody binding, and (iii) show that protein antigenicity can be significantly reduced by alteration of single critical residues without destroying biological activity.
Amino Acid Sequence↗
Evaluation of a low-temperature calcium phosphate particulate implant material: physical-chemical properties and in vivo bone response.
A study was conducted to evaluate the osteoconductive ability of a particulate, low-temperature hydroxylapatite (HA(LT)) material (OsteoGen; Impladent, Holliswood, NY). An implantable chamber model was used to determine the ability of this material to encourage bone ingrowth into channels lined with either rough-surfaced titanium or rough-surfaced plasma-sprayed hydroxylapatite. The HA(LT) material increased bone ingrowth into the titanium-lined channels comparable with that in plasma-sprayed hydroxylapatite-coated channels. It was incorporated into ingrowing bone without intervening soft tissue, with the bone bonding directly to the material surface in much the same fashion as it bonds at the plasma-sprayed hydroxylapatite surface. Mechanical testing of the ingrown bone showed no weakness because particles were incorporated. At 12 weeks, the particles began to show signs of dissolution. It was concluded that the HA(LT) material is a biocompatible, osteoconductive material that conducts bone ingrowth in much the same way as high-temperature particulate hydroxylapatite ceramics. This material has the additional desirable property of being slowly resorbable, a beneficial characteristic for many bone-filling applications.
Animals↗
[Secretion of hCG by mononuclear cells--a specific and essential reaction in pregnancy?].
Mononuclear cells in peripheral blood secrete immunoreactive hCG (ir-hCG) when they are stimulated in in-vitro culture with the proteinkinase C - activator phorbol-myristat-acetate (TPA). We examined the ir-hCG secretion in 61 fertile and 191 pregnant women and 38 men. Mononuclear cells of pregnant women secrete after TPA stimulation significantly more ir-hCG than mononuclear cells on non-pregnant but fertile women. This effect can be detected as early as 23rd days of a menstrual cycle which is accompanied by conception and persisted over the entire duration of a pregnancy. Maximal effects were observed in the 7th to 19th and 30th to 34th weeks of pregnancy. An artefact caused by adhesive serum-hCG could be excluded. The elevated potential of the mononuclear cells to be stimulated remained intact for about 14 days after termination of a normal pregnancy in the first trimester. An ir-hCG secretion similar to that seen in nonpregnant women was found in patients with early abortion. The possible physiological importance of the in-vivo secretion of beta-HCG during pregnancy is discussed.
Abortion, Incomplete↗
Synthesis and characterization of a recombinant myohemerythrin protein encoded by a synthetic gene.
The antigenic epitopes of the myohemerythrin (MHr) molecule have been studied extensively. The critical amino acid residues responsible for its immune recognition have been identified by using synthetic peptides and the technique of epitope scanning. To assess the true relevance of these techniques for determining the molecular mechanism of antigenic recognition and immunogenicity, the results obtained with isolated peptides should be tested in the context of the folded protein. To this end, we have designed and constructed a synthetic MHr gene, in modular form, which will allow subsequent alterations of nucleotide sequence encoding epitopes of interest. We have produced the recombinant protein at high level, and have shown by several criteria that it possesses the chemical, physical and immunological properties of the native worm protein. Thus, we have developed a valuable system for detailed immunological studies of the structure and chemistry required for antibody binding to protein.
Amino Acid Sequence↗
In vitro tendon cell growth rates on a synthetic fiber scaffold material and on standard culture plates.
Growth rates of rat tendon fibroblasts cultured in a three-dimensional carbon fiber matrix were compared with those of cells cultured on standard flat culture plates. The carbon fiber has been used as a tissue scaffold for tendon and ligament repair in animal and clinical studies. While cell growth on the culture plates appears to follow a growth curve containing a lag phase, a log phase, and plateau phase of growth, cell growth in the fiber matrix was characterized by a suppressed log phase of growth. SEM and cytotoxicity studies indicated that this effect was not caused by growth-inhibiting or cytotoxic substances from the carbon fiber. While we cannot rule out the possibility that cell growth was influenced by the surface chemistry of the carbon substrate, evidence from this and other studies suggests that the observed effect was caused by a lack of readily available surface area for cell attachment and growth on the small fibers. Because cell colonies growing on individual fibers are limited (at least in theory) to growing in two directions only, they enjoy limited opportunities for cell migration and growth--in contrast with cell colonies on flat culture plates. These results suggest fundamental differences in the mechanisms controlling cell growth on planar vs. three-dimensional fiber substrates.
Animals↗
Distribution of Ni, V, and petroleum hydrocarbons in recent sediments from the Veracruz coast, Mexico.
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Mexico↗
Microcapsules through polymer complexation. II. By complex coacervation of polymers containing a low charge density.
Relationships between ionizable group content, structure and molecular weight, solubility and solution behaviour, and the efficacy of ionic complex formation through complex coacervation, have been established for a range of sparingly soluble synthetic weak polyelectrolyte polymers with low charge content, based on hydroxyalkyl methacrylates. Selected polymers containing methacrylic acid (acidic) and dimethylaminoethyl methacrylate (basic) functionality show promise as capsule-forming pairs for the entrapment of mammalian cells. The solubility of basic polymers and their ability to form microcapsules with structural integrity is enhanced through quaternization of the N-methyl functionality to the quaternary ammonium group. The survival of guinea-pig erythrocytes encapsulated for 4 d in this promising system was shown by the Drabkin's test to be about 41% of the control sample.
Animals↗
Monkey model of severe volume-controlled hemorrhagic shock with resuscitation to outcome.
Seventeen cynomolgus monkeys under N2O analgesia and sedation were subjected to severe volume-controlled hemorrhagic shock (shed blood volume of 21 or 27 ml/kg). In 12 monkeys, resuscitation was started after increasing periods of hemorrhagic shock from 30 min to 5 h. In five additional monkeys, volume-controlled hemorrhage was modified at hemorrhagic shock 30 min to control MAP at 30 mmHg: resuscitation was started at hemorrhagic shock of 2 h. A clinically relevant resuscitation protocol consisted of a field phase from 0 to 6 h (lactated Ringer's solution, spontaneous breathing), and a hospital intensive care phase from 6 h to 48 h (blood, lactated Ringer's solution to mean arterial pressure (MAP) greater than or equal to 70 mmHg, controlled ventilation, advanced life support). Fifteen of the 17 monkeys survived. After outcome evaluation at 4 or 7 days, the eight monkeys with "moderate insult" had only transient functional impairment. Of the nine with "severe insult," three showed signs of moderate transient non-oliguric renal failure. Eight of the 12 monkeys studied morphologically showed scattered liver cell damage. None of the monkeys developed pulmonary dysfunction or functional or morphologic evidence of cerebral damage. This study establishes a new hemorrhagic shock-resuscitation model simulating field-to-hospital life support. Severe hemorrhagic shock with MAP 30-40 mmHg for 90-120 min (without trauma or sepsis) can lead to complete functional recovery after transient malfunction of liver and kidneys.
Animals↗
Does the occupational structure of the Hunter Region explain the high rates of ischaemic heart disease among its men?
To compare rates of ischaemic heart disease (IHD) among men in occupation groups defined by the new Australian Standard Classification of Occupations (ASCO) and to investigate whether their high mortality rates from IHD in the Hunter Region of New South Wales (NSW) could be explained by its occupational structure, we used official death records and data from the World Health Organization MONICA Project conducted in Newcastle. The study population consisted of men aged 25 to 64 years in NSW and in the Hunter Region for whom occupational information was available. For deaths from IHD between 1984 and 1988 in NSW, indirectly standardised mortality and morbidity ratios (SMRs) were: significantly low for professionals, 66 (95% confidence interval (CI) 60-71) and managers and administrators, 79 (95% CI 74-83); intermediate for paraprofessionals (92), clerks (94) and salesmen and personal service workers (97); and significantly high for tradesmen, 113 (95% CI 107-118), labourers and related workers, 118 (95% CI 113-124) and plant and machine operators and drivers, 125 (95% CI 118-133). Broadly similar patterns were found for IHD deaths and for fatal and nonfatal myocardial infarction in the Hunter Region. When occupation- and age-specific mortality rates from IHD were used to calculate SMRs for the Hunter Region, SMRs for all ASCO groups except paraprofessionals were over 100. Mortality rates for occupational groups classified by ASCO were consistent with well-established differences associated with socioeconomic status.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Who eats what? A comparison of dietary patterns among men and women in different occupational groups.
Dietary data were obtained during a community-based study of risk factors for heart disease in 1983. Results were compared for men and women in broadly defined socioeconomic groups based on occupation and education. People in higher status occupation groups and with more education, and women more than men, had food consumption patterns more consistent with current health promotion messages. For example, they reported eating more wholemeal or brown bread and more fresh fruit and vegetables, drinking more skim or low-fat milk, eating fewer eggs and having less sugar in hot drinks or on cereals. There was some evidence, however, of an interplay of influences of cost and health awareness. For example, retired men were less likely than employed men to eat butter, cream, fresh fruit and vegetables, while men in the upper socioeconomic groups reported relatively higher consumption of butter and cream. The results emphasise the need for a range of strategies aimed at specific subgroups in order to improve national dietary patterns in Australia.
Adult↗
Comparison of bovine collagen xenografts to autografts in the rabbit.
The use of bovine tendon as a xenograft material in humans is attractive because of its ready availability and favorable mechanical characteristics. Previous research has shown that the fibroblasts and some extracellular proteoglycans and glycoproteins, not the collagen matrix itself, in bovine tendon are primarily responsible for its antigenicity. Various attempts have been made to decrease the antigenicity of these grafts. A chloroform/methanol (CM) extraction procedure has been developed that selectively removes the fibroblasts from bovine tendon without destroying the collagen matrix. The mechanical, immunologic, and local host tissue responses to these grafts were compared to autografts and to untreated and glutaraldehyde-treated bovine tendon xenografts. The humoral immune response to a purified bovine Type I collagen product was also studied. The central two-thirds of a rabbit Achilles tendon were replaced with a reversed autograft or an experimental graft. Histologic examination of one- and two- week specimens showed an acute inflammatory response to all grafts. Untreated grafts stimulated a severe inflammatory response and were almost completely resorbed by two weeks. Glutaraldehyde-treated grafts were encapsulated. Cellular repopulation was minimal and inflammatory response was more persistent than in the autograft and CM groups. Inflammatory response to CM-treated grafts was similar to that of autografts. The CM grafts repopulated rapidly with host cells. The mechanical strength of CM grafts was equal to autograft controls at 12 weeks. The mechanical strength of untreated and glutaraldehyde-treated grafts was significantly lower. Measurement of the humoral immune response to these grafts was conducted in an independent group of animals using an enzyme-linked immunosorbent assay. A significant antibody response to untreated, glutaraldehyde-fixed, and CM-treated grafts was detected at 30 days. Antibody titers to glutaraldehyde-fixed and untreated grafts remained elevated at 60 and 90 days. In the CM group, antibody titers decreased to the level of autograft controls by 90 days. No significant antibody response was detected toward purified bovine Type I collagen.
Achilles Tendon↗
[Cervical pregnancy--an unusual form of extrauterine pregnancy].
We present a case report about a 27 years old patient with cervical pregnancy. The extrauterine implantation was recognized in the 14th week of gestation. Abdominal hysterectomy was performed because of a life threatening bleeding.
Adult↗
A new canine model to evaluate the biological response of intramedullary bone to implant materials and surfaces.
A new canine model utilizing an implantable chamber with multiple bone ingrowth channels has been used to study the response of intramedullary bone to various implant materials and surfaces. The first group of dogs received implants containing channels lined by smooth-surfaced coupons of titanium, titanium alloy, sputter-hydroxyapatite-coated (HA-coated) titanium alloy, and polyethylene. A pattern of early initial bone ingrowth by 2 weeks, becoming maximal at 6 to 12 weeks with remodeling to a more mature lamellar bone, and later resorption by 24 weeks was seen for all test groups, with fibrous tissue interfaces covering the smooth test coupons at all time points. Significantly increased bone ingrowth in the sputter-HA coated group was found only at 6 weeks. The second group of dogs received implants with channels lined by surface-roughened coupons of either titanium or plasma-HA-coated titanium, half of which were also packed with a crystalline-HA grouting at the time of surgery. At both 6 and 12 weeks, bone ingrowth was greatly enhanced by the presence of the plasma-HA coating or the crystalline-HA grouting as compared to the uncoated titanium channels. Histologically, bone was seen to bond directly to the plasma-HA coating and the crystalline-HA grouting. A thin fibrous tissue layer was noted between bone and the titanium in most areas, but evidence of direct bone contact to the metal surface was seen. Mechanical testing in tension of intact coupon-bone-coupon units revealed significant strength of the bone-plasma-HA bond, with failure initiating at the metal-HA interface with forces of 15.3 N at 6 weeks, increasing to 44.8 N at 12 weeks. Plasma-HA-lined channels with crystalline-HA packing required similar forces for failure. No significant adhesion strength was noted for the titanium channels at 6 weeks, and only the crystalline-HA-filled channels displayed measurable strength of the bone-titanium interface at 12 weeks, with a force of 9 N needed for failure.
Animals↗
[Anesthesia for laparoscopy in sterile patients].
During 5 years 382 laparoscopies were carried through in female patients with sterility in different kinds of anaesthesia (Intubation anaesthesia, spinal anaesthesia, and i.v. anaesthesia). We found the most advantageous results in the cases of i.v. anaesthesia with Ketamin and Diazepam.
Adult↗
In-vitro tendon cell growth on synthetic fiber implant materials: biological implications.
The growth of tendon cell colonies on synthetic fiber materials used as soft tissue implants was compared to the growth of such cell colonies on flat plastic surfaces used as standard cell culture substrates. Fundamental differences in growth characteristics were observed, and a mathematical model was developed.
Animals↗
[Chlamydia infection in gynecology].
The frequency of chlamydial infections was investigated by means of the McCoy culture technique and a serological procedure using the microimmunofluorescence test in female outpatients showing suspect symptoms; in patients suffering from acute salpingitis, and in women with involuntary infertility. In 18.6% of 290 subjects of the first group, chlamydiae were isolated from cultures. Of 26 patients with acute salpingitis, Chlamydia trachomatis could be detected in 10. The high frequency of positive serological tests suggests chlamydial infection to constitute an important etiological factor in female infertility and extrauterine pregnancies.
Adolescent↗