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Biomedical subjects

A Jacobson

Publications and source records attributed to A Jacobson.

At least 163 records · Page 9Linked to original sources
PubMed1980

Detrimental effect of endometrial biopsies on pregnancy rate following human menopausal gonadotropin/human chorionic gonadotropin-induced ovulation.

The effect of luteal phase endometrial biopsy was studied in 33 anovulatory women treated with human menopausal gonadotropins (hMG) to induce ovulation and pregnancy. Over-all, 33 of 85 ovulatory cycles resulted in pregnancy (39%). Of 50 nonbiopsied cycles, 26 resulted in pregnancy (52%) whereas only 7 of 35 biopsied cycles resulted in pregnancy (20() (P less than 0.01). Four pregnancies terminated in spontaneous first-trimester abortions, 12% in the nonbiopsied group and 14% in the biopsied group. Luteal phase endometrial biopsy significantly lowers pregnancy rates in hMG-induced ovulatory cycles, but does not change abortion rates.

Abortion, Spontaneous↗
PubMed1980

Inhibition of respiration and ion uptake by 2,3,5-triiodobenzoic Acid in excised barley roots.

The addition of 1 micromolar 2,3,5-triiodobenzoic acid (TIBA) to solutions containing KCl resulted in the inhibition of K and Cl uptake in excised barley roots. The effectiveness of TIBA as an inhibitor increased as the pH of the treatment solution decreased and approached the pK(a) of TIBA. A lag period of approximately 20 minutes existed prior to the onset of TIBA induced inhibition of ion uptake. Respiratory activity was also inhibited by TIBA. The data suggest that in this material, TIBA functions by entering the cytoplasm and inhibiting metabolism. Comparisons made on the effect of added Ca, showed that at pH 5.7 and higher, Ca had no effect on ion uptake whereas at lower pH values the presence of Ca enhanced uptake by offsetting the deleterious effects of H(+).

Journal Article↗
PubMed1980

Diagnosis of mental disorder in adults and increased use of health services in four outpatient settings.

The differential use of medical services by patients with and those without a diagnosis of mental disorder was examined in four adult populations by age, sex, diagnosis, and medical department used. The four settings offered comprehensive services to patients who varied greatly in socioeconomic status. In all four settings patients with a diagnosis of mental disorder used all services and general health services more than patients without such a diagnosis. Results document increased medical morbidity and a greater likelihood of a diagnosis of an ill-defined condition in patients with mental disorder than that found in patients without a diagnosis of mental disorder.

Adolescent↗
PubMed1980

Orthognathic diagnosis using the proportionate template.

Most traditional cephalometric analyses relate various craniofacial landmarks to anterior cranial base (sella or nasion) or to Frankfort horizontal plane. Such analyses do not accurately reflect the extent of anteroposterior or vertical jaw dysplasias. In addition, traditional cephalometric analyses do not provide adequate information relative to the specific jaw at fault, that is, whether either or both are too protrusive or retropositioned. The Wits appraisal provides reliable information relative to anteroposterior relationship of the jaws to each other. The proportionate template is designed to enable jaw dysplasias to be identified on lateral cephalometric headfilms without having to rely on either anterior cranial base or Frankfort horizontal plane. Various methods of applying the template are outlined, and the advantages and its usefulness in clinical situations are described.

Body Height↗
PubMed1979

The maxillary orthopedic splint.

Craniomaxillary orthopedic correction of the skeletal imbalance of Class II malocclusions is often the desired method of treatment in these cases. The ability to apply a "pure" orthopedic force to the maxillary complex has so far eluded research efforts. However, the use of a maxillary splint with a high-pull extraoral traction assembly has been shown to be most effective in reducing Class II skeletal dysplasias through a combination of dentoalveolar and basal bone changes. Force delivery to the maxillary complex in Class II skeletal jaw disharmonies is through the teeth. The philosophy behind the use of the maxillary splint is that if the force delivered to the upper jaw involved the use of all the upper teeth (and hard palate) rather than only the maxillary first molars, as in conventional extraoral orthodontic therapy, the effect on the jaws would be more orthopedic than orthodontic in nature. The advantages of the use of the maxillary splint in the younger patient with a severe Class II malocclusion are that it reduces the vulnerability of the maxillary incisors to accidental fracture, while concomitantly reducing the Class II dysplasia, thereby effectively shortening the later-stage multiband corrective time and procedures. Further advantages of the maxillary splint described are ease of construction and clinical application, which makes it an attractive appliance for use in dental clinics or institutions in which patient volume, infrequent visits, and ecomomic factors are major considerations. This preliminary report on the philosophy of treatment procedure and description of the appliance design is to be followed by a further cephalometric and clinical evaluation of results achieved with its use.

Cephalometry↗
PubMed1979

A key to the understanding of extraoral forces.

By following certain basic principles, the effects, advantages, and disadvantages of the wide assortment of extraoral assemblies marketed are easily understood. The key to this understanding is the appreciation of the relationship of the line of action of the force application to the center of resistance of the tooth. These principles are discussed in three planes of space: sagittal, coronal, and transverse. Because of the many variables and complexity of mathematically computing the force effects of unilateral or asymmetric extraoral assemblies on molar teeth, a mechanical testing apparatus was designed to accommodate the various face-bows. Not all the designs proved effective, and many of the clinical side effects of the respective face-bow designs became manifest on mechanical testing.

Cephalometry↗
PubMed1979

The proportionate template as a diagnostic aid.

Many traditional cephalometric analyses used do not consistently reflect the extent of anteroposterior or vertical jaw dysplasias. Nor do such analyses give accurate information as to which jaw(s) is at fault. The proportionate template is designed as a diagnostic aid which enables the clinician to identify and determine rapidly the extent of craniofacial skeletal jaw discrepancies in adults. The template is found to be particularly useful for orthodontists and surgeons engaged in orthognathic surgery. (Proportionate templates are available upon request from the author).

Adult↗
PubMed1978

The craniofacial skeletal pattern of the South African Negro.

Lateral cephalometric head film measurements on twenty-seven male and twenty-eight female adult craniums and mandibles with excellent occlusions were compared with similar measurements on Caucasoids with excellent occlusions. Among the differences between the two groups is the forward position of the short maxilla relative to the anterior cranial base in the South African Negro. The forward location of point A has the effect of increasing the ANB angle, since the relative position of point B in both groups is much the same. Unlike the American Negro, the labial inclination of the upper incisors in the South African Negro is not pronounced but is similar to the inclination observed in Caucasoids. Because of the large ANB angle, the lower incisors in the S.A. Negro (as in the American Negro) are severely labially inclined. Ramus height in the S.A. Negro is shorter than that of Caucasoids and appears to be related to the steep mandibular plane observed in the former population group.

Black People↗
PubMed1978

Novel properties of bacterial elongation factor Tu.

We have characterized novel properties of the bacterial protein synthesis elongation factor Tu which indicate that it may function as a structural protein. Under appropriate conditions, elongation factor Tu polymerizes to form filaments and, more often, bundles of filaments. It is also the predominant component of a complex of proteins from Escherichia coli that undergoes reversible polymerization in the presence of KCl and MgCl2. In addition, purified elongation factor Tu binds tightly to DNase I in the presence of 10 mM MgCl2. In crude extracts the factor shows no binding in the presence or absence of MgCl2. These properties suggest that elongation factor Tu may have certain actin-like properties and that it has cellular functions other than its role in protein synthesis.

Bacterial Proteins↗
PubMed1977

The craniofacial pattern of the Lengua Indians of Paraguay.

Lateral cephalometric headfilms of 30 male and 30 female Lengua Indians taken in the Chaco area of Paraguay were compared with a sample of 23 male and 25 female South African Caucasoids with excellent occlusion. The most obvious difference noted between the two population groups was the degree of prognathism evident in the Lengua. This was attributed to the generally shorter anterior cranial base in the latter group rather than to the size or forward positioning of their jaws. The significantly larger ANB (Subspinale, Nasion, Supramentale) angle observed in the Lengua was attributed to one or both of two factors, namely, the short anterior cranial base or the clockwise rotation (forward tipping) of the jaws relative to the anterior cranial base. Chinpoint position relative to the anterior cranial base in the Lengua is not much different from that of our Caucasoid sample. The lower incisor teeth in the Lengua, but not the upper ones, are more labially inclined than those of the Caucasoids.

Adolescent↗