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Biomedical subjects

K Kaufman

Publications and source records attributed to K Kaufman.

At least 73 records · Page 4Linked to original sources
PubMed1981

Efficacy of continuous treatment with radiation in a rat brain-tumor model.

Rats bearing intracerebral 9L/Ro tumors were treated with 10 daily fractions of cesium-137 gamma-rays, BCNU, or combinations of these to agents beginning on either Day 10 or Day 12 after implantation. The treatments were administered either 5 days/week for 2 weeks, with the weekend off, or 10 consecutive days. The median day of death for untreated tumor-bearing rats was Day 15, so Day 12 tumors can be considered late tumors and Day 10 tumors can be considered moderately early. Although all single- and multiple-agent treatments significantly (p less than 0.05) increased the lifespan of tumor-bearing rats over that of the untreated controls, and all multiple-agent schedules significantly (p less than 0.05) increased the lifespan over that of the single-agent therapies, none of the 10 consecutive day schedules increased the lifespan of tumor-bearing rats significantly (p less than 0.2) over that obtained with the 5-day/week schedules. Thus, the evidence from this tumor model suggests that no significant improvement in lifespan would be expected if malignant brain tumors were treated with radiation 7 days a week, either alone or in combination with chemotherapeutic agents such as BCNU.

Animals↗
PubMed1980

Graduate training in clinical psychology: a view from the consumer.

Recent graduates from APA-approved doctoral programs in clinical psychology were asked to rate the adequacy of their training in a variety of skill areas (N = 316). For the most part, respondents were relatively satisfied with their training and were most satisfied with traditional skills in therapy and assessment. Comparisons of males and females, practitioners and academicians, and traditional clinical vs. community-oriented programs resulted in few significant differences. In light of other recent findings, the present results suggest that satisfaction with training and satisfaction with professional work role are not the same. Implications of these results and suggestions for future research are discussed.

Education, Medical, Graduate↗
PubMed1975

In vivo testing of hypoxic radiosensitizers using the KHT murine tumour assayed by the lung-colony technique.

The KHT transplantable tumour of C3H mice has been used as a model tumour for the invivo study of hypoxic cell sensitizers. Eleven sensitizers comprising four nitrofuran five nitrobenzene and two nitroimidazole derivatives, which have been shown to be effective on hypoxic mammalian cells in vitro, have been investigated. Two of these compounds, metronidazole (2-methyl-5-nitroimidazole-1 ethanol) and tinidazole (ethyl [2-(2'-methyl-5'-nitro-1'-imidazolyl) ehtyl] sulfone), showed signs of hypoxic cell-sensitization in vivo when given systemically by intraperitoneal injections. In addition, preliminary testing of the nitrobenzene NDPP (P-NITRO-3-DIMETHYL-PROPRIOPHENONE HYDROCHLORIDE) INDICATED THAT WHEN IT WAS INJECTED DIRECTLY INTO THE TUMOUR AND IRRADIATION WAS COMPLETED WITHIN TEN MINUTES AFTER INJECTION, APPRECIABLE SENSITIZATION WAS OBTAINED. More detailed studies indicated that both metronidazole at 1,500 mg/kg and tinidazole at 750 mg/kg given intraperitoneally gave an enhancement ratio of 1-5 for a chronically hyopix cell population in this solid tumour in air-breathing mice. Measures of plasma levels of metronidazole and enhancement ratios obtained in the present in vivo system seem in relative agreement with the in vitro and in vivo results of others.

Animals↗
PubMed1971

Small ribosomal ribonucleic acid species of Saccharomyces cerevisiae.

Yeast ribosomes contain two small molecular-weight species of ribonucleic acid (RNA), in addition to transiently associated transfer RNA. The 5S RNA species is part of the large ribosomal subunit and appears to be exactly the same size as 5S RNA from other organisms. There is another RNA molecule, approximately 5.8S or 150 nucleotides in size, which is noncovalently attached to the 25S ribosomal RNA and can be freed by gentle heating or urea treatment. Neither 5 nor 5.8S RNA are methylated. The 5.8S RNA is probably derived from a part of the 35S precursor RNA, whereas the 5S RNA is made de novo. These results substantiate the notion that ribosome biosynthesis in yeast is analogous to that of the higher eukaryotes.

Acrylates↗
PubMedDate not supplied

Protein-protein interaction of the Ro-ribonucleoprotein particle using multiple antigenic peptides.

Protein protein interactions play a significant role in maintaining the structural and functional integrity of the cell. We used multiple antigen peptides (MAPs) to analyze such interactions within the Ro (or SSA) ribonucleoprotein complex. Our data showed that 60 kD Ro and La colocalize in the nucleus of the cell. Previous data have indicated that 60 kD Ro and La co-exist via interactions with the hYRNAs. We were interested to see whether 60 kD Ro and La interact with each other through protein protein interactions. MAPs were produced with sequences derived from the autoepitopes of 60 kD Ro. When used in agarose immunodiffusion certain MAPs formed precipitin lines specifically with Ro and La antigens. Used in affinity chromatography the Ro MAPs purified the Ro ribonucleoprotein particle from lymphocyte extract. Solid phase immunoassay and surface plasmon resonance (SPR) confirmed the observations obtained with agarose diffusion. Using SPR, kinetic analyses gave an apparent affinity constant of about 1 x 10(7) M(-1) for Ro-MAP-60 kD Ro interactions. The autoantigens Ro and La are specific targets in autoimmune diseases, particularly systemic lupus erythematosus (SLE) and Sjögren's syndrome, and are known to exist together as a complex with hYRNAs. The present data indicate that there are protein-protein interactions between Ro and La.

Amino Acid Sequence↗
PubMedDate not supplied

Three-dimensional characteristics of cartilaginous and bony components of dysplastic hips in children: three-dimensional computed tomography quantitative analysis.

A cartilage-viewing technique was developed to overcome the shortcoming of not seeing the cartilaginous components, believed to play more important role than the osseous components in children's hips, with computed tomography. This technique was applied to 25 dysplastic hips in children younger than 10 years to evaluate their global and local deficiencies. The findings helped us to understand more about their individual problems. To quantify the three-dimensional (3-D) parameters of acetabular anatomy and femoral head coverage, a measuring technique was developed based on digitization of the 3-D coordinates and fitting of every component of the hip. The improved images and the quantified parameters were expected to aid the planning, formulation, and even simulation of individualized surgical treatment for children with developmental dysplasia of the hip.

Acetabulum↗
PubMedDate not supplied

Hip function and gait in patients treated for bladder exstrophy.

Patients with bladder exstrophy demonstrate pubic diastasis with external rotation of the ilia and posterolateral orientation of the acetabula. Iliac osteotomy is performed to approximate the pubis and thus facilitate the genitourinary repair. The role of iliac osteotomy in the correction of gait abnormalities is controversial. Our goals in this study were to define the presence of hip pathology and gait abnormalities in patients treated for bladder exstrophy and to evaluate the effect of iliac osteotomy. We reviewed pelvic radiographs and gait studies in 15 children. The treatment included bilateral iliac osteotomy in nine of 15 of these patients. We found minor hip dysplasia in two patients, but we saw no evidence of subluxation or dislocation. Pubic diastasis increased with age and was not related to osteotomy. Patients had slightly less passive hip internal rotation than age-matched controls. There was no correlation between the restriction of hip internal rotation and the amount of pubic diastasis. Two thirds (10 of 15) of the patients exhibited increased lower extremity external rotation during gait. None of the subjects demonstrated a waddling gait (gluteus medius lurch) described in the literature. Based on our results, iliac osteotomy does not affect gait patterns in children with bladder exstrophy. However, we believe that it is indicated to improve the results of genitourinary repair.

Adolescent↗
PubMedDate not supplied

Prediction of muscle recruitment and its effect on joint reaction forces during knee exercises.

This study examined the hypothesis that muscle recruitment of the tibiofemoral joint and joint reaction forces during isometric and isokinetic exercises depends on the existing degrees of freedom of the knee and the direction and type of external load applied during exercise. When three-dimensional knee joint rotation was considered (three degrees of freedom), antagonistic muscle activities were predicted using an inverse dynamic problem formulation and muscle modeling optimization procedures. The results showed that the antagonistic activities of flexors during knee flexion/extension exercise increased the joint compressive forces and decreased the anterior tibial shear forces. Comparison of different knee joint modeling assumptions indicated that modeling a single degree of freedom in flexion/extension for the knee will underestimate the antagonistic muscle function.

Biomechanical Phenomena↗
PubMedDate not supplied

Hickman catheter dislodgement due to pendulous breasts.

Dislodgement of Hickman, Broviac, and Mediport catheters is a rare but recognized complication. To date, no specific etiology for this has been cited. We present five cases of dislodgement due to positional changes in large-breasted women and one man with gynecomastia. Apparently, motion in the subcutaneous tissue secondary to gravitational forces on large breasts causes downward and outward traction on the subcutaneous portion of the catheter. Variations in placement technique to help avoid this complication are described.

Adult↗
PubMedDate not supplied

The anterior cruciate ligament in controlling axial rotation. An evaluation of its effect.

Changes in axial tibial rotation after anterior cruciate ligament sectioning were evaluated in 14 fresh human knee joints. Simulation of vertical stance in a quadriceps-stabilized knee was performed. Internal and external rotational torques were applied before and after anterior cruciate ligament sectioning. Pivot shift tests were done in the intact and anterior cruciate ligament sectioned knee. Results of pivot shift tests were all negative before sectioning and positive after isolated sectioning. No significant change in axial rotation occurred between the intact and sectioned knee for external rotation (P = 0.24) or internal rotation (P = 0.12). Presence of a load at the femoral housing in both the intact and ligament-sectioned knees caused a significant change in external rotation (P < 0.0001). No significant change was noted in internal rotation between loaded and unloaded states (P = 0.70). Total tibial rotation in the intact knee was noted to vary between 31 degrees at 0 degree of flexion and 42 degrees at 60 degrees of flexion. These results suggest that the anterior cruciate ligament does not play a significant role in limiting axial rotation and that rotational instability is not a major factor after isolated anterior cruciate ligament rupture.

Aged↗