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Biomedical subjects

T Jacobs

Publications and source records attributed to T Jacobs.

16 recordsLinked to original sources
PubMed1992

Control of the cell cycle.

Cell division is arguably the most fundamental developmental process for single-celled and multicellular organisms alike. The pathway from one cell division to the next is known as the cell cycle. A conserved biochemical regulatory network controls progress along this pathway in plants, animals, and yeasts. This review is intended to serve as a primer on the current state of the eukaryotic cell cycle regulatory model, an introduction to the special roles of cell division and its control in plant development, and a review of recent progress in applying the universal mitotic control paradigm to higher plant systems.

Amino Acid Sequence↗
PubMed1992

17 beta-estradiol prevents osteopenia in the oophorectomized rat treated with cyclosporin-A.

Cyclosporin-A (CsA) administered to the oophorectomized rat exaggerates the high turnover osteopenia associated with oophorectomy alone. This study investigated whether 17 beta-estradiol replacement could influence the development of osteopenia in the oophorectomized rat treated with CsA. Ninety female Sprague-Dawley rats, approximately 300 g in weight, were divided into 6 groups of 15 each and treated according to the following protocol: group A were sham operated (control), group B underwent oophorectomy (Ox), group C underwent Ox and received CsA (15 mg/kg, by daily gavage) for 28 days (Ox and CsA), group D underwent Ox and received CsA and a 0.1 mg 17 beta-estradiol pellet (EP) implanted sc (Ox, CsA, and EP), group E underwent Ox and received EP (Ox and EP), and group F, which was intact and nonoperated, received CsA (CsA). Rats were weighed and bled on days -7, 0, 7, 14, 21, and 28 for measurement of blood ionized calcium, bone Gla protein (BGP), 17 beta-estradiol, and PTH. Bone histomorphometry was determined after double tetracycline labeling. On day 28, serum 17 beta-estradiol was undetectable in groups B (Ox) and C (Ox and CsA), and similar to group A (control) in groups D (Ox, CsA, and EP), E (Ox and EP), and F (CsA). Oophorectomy resulted in a significant gain in weight in groups B (Ox) and C (Ox and CsA), which was prevented by 17 beta-estradiol in groups D (Ox, CsA, and EP) and E (Ox and EP). On day 28, serum BGP levels were higher in groups B (Ox; 73.58 +/- 3.63 ng/ml), C (Ox and CsA; 85.05 +/- 9.88), and F (CsA; 81.35 +/- 3.4) compared to group A (control; 46.07 +/- 5.52; P less than 0.05), while 17 beta-estradiol in groups D (Ox, CsA, and EP; 38.65 +/- 2.85) and E (Ox and EP; 41.89 +/- 1.89) prevented this rise (P = 0.01). BGP levels in group C (Ox and CsA) were higher on days 14 and 21 compared to group B (Ox). Groups D (Ox, CsA, and EP) and E (Ox and EP) had elevated blood ionized calcium levels from day 7 onward. Serum PTH levels were unchanged. Histomorphometric analyses of tibial metaphyses revealed increased parameters of bone formation and resorption, with significant loss of bone volume, in groups B (Ox; 12.03 +/- 1.40%) and C (Ox and CsA; 11.43 +/- 2.20) vs. group A (control; 24.36 +/- 2.37; P less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Electrophoretic gel image analysis software for the molecular biology laboratory.

We present GelReader 1.0, a microcomputer program designed to make precision, digital analysis of one-dimensional electrophoretic gels accessible to the molecular biology laboratory of modest means. Images of electrophoretic gels are digitized via a desktop flatbed scanner from instant photographs, autoradiograms or chromogenically stained blotting media. GelReader is then invoked to locate lanes and bands and generate a report of molecular weights of unknowns, based on specified sets of standards. Frequently used standards can be stored in the program. Lanes and bands can be added or removed, based upon users' subjective preferences. A unique lane histogram feature facilitates precise manual addition of bands missed by the software. Image enhancement features include palette manipulation, histogram equalization, shadowing and magnification. The user interface strikes a balance between program autonomy and user intervention, in recognition of the variability in electrophoretic gel quality and users' analytical needs.

Computer Peripherals↗
PubMed1989

The role of bone scan and radiography in the diagnostic evaluation of suspected pedal osteomyelitis.

The authors reviewed the three-phase bone scans and radiographs of 24 patients with suspected pedal osteomyelitis who also had histologic confirmation of the diagnosis. Twenty patients had a pedal ulcer, cellulitis, or necrosis. Sensitivity and specificity of bone scanning were 70% and 43% respectively. Sensitivity and specificity of radiography were 70% and 50% respectively. The non-invasive diagnosis of pedal osteomyelitis remains problematic due to the poor specificity of bone scans and radiographs.

Adult↗
PubMed1986

[Pneumocystis carinii pneumonia--a review].

Pneumocystis carinii pneumonia is a clinically, roentgenologically, and serologically uncharacteristic pneumonia of the immunodeficient patient and is caused by the opportunistic parasite Pneumocystis which is most likely a protozoon. The untreated disease is lethal. The epidemiologic, clinic, and histologic features of P. carinii pneumonia are different from those of the interstitial plasmacellular pneumonia that occurred in malnourished and premature infants between 1930 and 1960 in Europe and was caused by the same organism. P. carinii is restricted to the alveoli of the lung. Material for the direct microscopic diagnosis of the parasite can be produced by bronchoalveolar lavage. The trophozoites of P. carinii are preferably stained by Giemsa stain and the cystwalls by methenamine-silver. For a reliable diagnosis both methods should be used.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Compliance with maintenance therapy in a private periodontal practice.

The purpose of this study was to determine patient compliance with suggested maintenance schedules. All patients eligible for maintenance therapy in a private periodontal practice were included. The study covered a period of 8 years. All patients had chronic inflammatory periodontal disease and had been eligible for at least 1 year of maintenance therapy before the close of data collection. A total of 961 patients were studied; only 16% complied with recommended maintenance schedules. Erratic compliance was found in 49% of the patients and 34% never reported for any maintenance therapy.

Adolescent↗
PubMed1982

Cell wall-associated protein antigens of Streptococcus salivarius: purification, properties, and function in adherence.

Three cell wall-associated protein antigens (antigens b, c, and d) were isolated from mutanolysin-solubilized cell walls of Streptococcus salivarius HB and purified to apparent homogeneity by a combination of ion-exchange chromatography, gel filtration, and immunoadsorption chromatography. Antigens b and c were also isolated from culture supernatants. Antigen b consisted of more than 80% protein and had an apparent molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of 320,000. Antigen c consisted of 57% protein, about 30% neutral sugar, and about 13% amino sugar, and its glycoprotein nature was confirmed by specific staining techniques. During sodium dodecyl sulfate-polyacrylamide gel electrophoresis antigen c resolved into two or more bands, depending on the source or the isolation procedure, in the molecular weight range from 220,000 to 280,000. Antigen d consisted of 95% protein and was observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis as two bands with molecular weights of 129,000 and 121,000. Under nondenaturing conditions all three antigens had molecular weights in the range from 1 x 10(6) to 3 x 10(6) as determined by gel filtration. The amino acid compositions of antigens b, c, and d were characterized by low amounts of basic amino acids and relatively high levels of nonpolar amino acids. Among oral streptococcal species antigens b and c were virtually restricted to strains of S. salivarius and most often to serotype I strains. Antigen b was recognized as the factor that mediates coaggregation of S. salivarius with Veillonella strains. The purified protein retained its biological activity. Antigen c could be linked to functions relating to adhesion of the streptococci to host tissues on the basis of its absence in mutant strains and blocking by specific antisera. The purified molecule had no detectable biological activity. Antigen d could not be linked to an established adhesion function.

Adhesiveness↗
PubMed1979

An intraspinal sympathetic preganglionic pathway: physiologic evidence in the cat.

Electrical stimulation of the zona intermedia of the lower thoracic/upper lumbar cat spinal cord resulted in increases of heart rate (HR), blood pressure (BP) and cardiac contractility (dp/dt). Sites of maximal cardiovascular response (SMCR) were localized histologically to the intermediolateral nucleus (ILN). The inotropic and chronotropic responses were abolished by spinal cord transection or hemisection two to three segments rostral to the site of stimulation. Discrete electrolytic lesions in the white matter adjacent to the ILN were also shown to markedly decrease or abolish the chronotropic and inotropic responses elicited by stimulation of a more caudal SMCR. Longitudinal spinal section resulted in decreased cardiovascular responses from an SMCR; these changes were larger on the left side and greatest for BP as compared to HR and dp/dt. These findings indicate the existence of an ascending intraspinal cardiovascular pathway located in the deep white matter adjacent to the ILN. They further suggest that this is the intraspinal sympathetic preganglionic pathway recently described anatomically.

Animals↗
PubMed1966

Cryptic malaria.

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Humans↗