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Biomedical subjects

M Altman

Publications and source records attributed to M Altman.

At least 19 recordsLinked to original sources
PubMed2000

Conformational behavior of ionic self-complementary peptides.

Several de novo designed ionic peptides that are able to undergo conformational change under the influence of temperature and pH were studied. These peptides have two distinct surfaces with regular repeats of alternating hydrophilic and hydrophobic side chains. This permits extensive ionic and hydrophobic interactions resulting in the formation of stable beta-sheet assemblies. The other defining characteristic of this type of peptide is a cluster of negatively charged aspartic or glutamic acid residues located toward the N-terminus and positively charged arginine or lysine residues located toward the C-terminus. This arrangement of charge balances the alpha-helical dipole moment (C --> N), resulting in a strong tendency to form stable alpha-helices as well. Therefore, these peptides can form both stable alpha-helices and beta-sheets. They are also able to undergo abrupt structural transformations between these structures induced by temperature and pH changes. The amino acid sequence of these peptides permits both stable beta-sheet and alpha-helix formation, resulting in a balance between these two forms as governed by the environment. Some segments in proteins may also undergo conformational changes in response to environmental changes. Analyzing the plasticity and dynamics of this type of peptide may provide insight into amyloid formation. Since these peptides have dynamic secondary structure, they will serve to refine our general understanding of protein structure.

Amino Acid Sequence↗
PubMed1999

Biological surface engineering: a simple system for cell pattern formation.

Biological surface engineering using synthetic biological materials has a great potential for advances in our understanding of complex biological phenomena. We developed a simple system to engineer biologically relevant surfaces using a combination of self-assembling oligopeptide monolayers and microcontact printing (muCP). We designed and synthesized two oligopeptides containing a cell adhesion motif (RADS)n (n = 2 and 3) at the N-terminus, followed by an oligo(alanine) linker and a cysteine residue at the C-terminus. The thiol group of cysteine allows the oligopeptides to attach covalently onto a gold-coated surface to form monolayers. We then microfabricated a variety of surface patterns using the cell adhesion peptides in combination with hexa-ethylene glycol thiolate which resist non-specific adsorption of proteins and cells. The resulting patterns consist of areas either supporting or inhibiting cell adhesion, thus they are capable of aligning cells in a well-defined manner, leading to specific cell array and pattern formations.

3T3 Cells↗
PubMed1999

Can prism adaptation for acquired esotropia be accomplished in a shorter time frame?

PURPOSE: Results of the Prism Adaptation Study (PAS) indicated that surgical success rates were highest when augmented surgery was performed for the increased angle of deviation in the prism adaptation responders who underwent surgery for the prism-determined angle of esotropia. The purpose of this study was to see if the prism adaptation response process could be performed in a shorter time span than dictated in the PAS protocol (minimum, 4-7 days). METHODS: After the prescription of appropriate spectacles, patients with acquired stable esotropia were prism adapted and then reexamined and readapted if necessary at 24 hours and 4 to 7 days. The 4- to 7-day visit was the determining visit in the PAS. The question in this study was whether the 24-hour visit would provide the same end point and allow adaptation in a shorter period of time. In addition, a motor end point was used in this study, whereas in the PAS, the end point was both motor and sensory. RESULTS: Thirty-two patients met the entry criteria. Nineteen of the 32 patients built up their entry angle during the prism adaptation process. Thirty of the 32 patients who left the office stable at the 24-hour visit remained stable at the 4- to 7-day visit. CONCLUSION: If the 4- to 7-day visit is used as the "gold" standard, 94% of the patients in this study would not have benefited from a longer (beyond 24 hours) wear time of prisms. With the use of motor stability, prism adaptation can be carried out in a reproducible and timely fashion.

Adaptation, Ocular↗
PubMed1998

Rapid healing of venous ulcers and lack of clinical rejection with an allogeneic cultured human skin equivalent. Human Skin Equivalent Investigators Group.

OBJECTIVE: To test the safety, efficacy, and immunological impact of a cultured allogeneic human skin equivalent (HSE) in the treatment of venous ulcers. DESIGN: Prospective, randomized study. SETTING: Multicenter study in the outpatient setting. INTERVENTION: Each patient with a venous ulcer received either compression therapy alone or compression therapy and treatment with HSE. The patients were evaluated for HSE safety, complete (100%) ulcer healing, time to wound closure, wound recurrence, and immune response to the HSE. OUTCOME: The study was completed as planned in 293 randomized patients. RESULTS: Treatment with HSE was more effective than compression therapy in the percentage of patients healed by 6 months (63% vs 49%; P=.02, Fisher exact test, 2-tailed) and the median time to complete wound closure (61 days vs 181 days; P=.003, log-rank test). Treatment with HSE was superior to compression therapy in healing larger (> 1000 mm2; P=.02) and deeper ulcers (P=.003) and ulcers of more than 6 months' duration (P=.001). Occurrence of adverse events was similar in both groups. No symptoms or signs of rejection occurred in response to treatment with HSE, and no HSE-specific immune responses were detected in vitro to bovine collagen or to alloantigens expressed on keratinocytes or fibroblasts. CONCLUSIONS: Treatment with HSE healed venous ulcers more rapidly and in more patients than compression therapy alone. There was no clinical or laboratory evidence of rejection or sensitization in response to HSE application. These data suggest that HSE represents a significant advance in the treatment of venous ulcers, particularly those that are difficult to heal.

Aged↗
PubMed1996

A community based study of failure to thrive in Israel.

OBJECTIVE: To examine the characteristics of infants suffering from failure to thrive in a community based cohort in Israel and to ascertain the effect of failure to thrive on their cognitive development. METHODS: By review of records maintained at maternal and child health clinics in Jerusalem and the two of Beit Shemesh, epidemiological data were obtained at age 15 months on a cohort of all babies born in 1991. For each case of failure to thrive, a matched control was selected from the same maternal and child health clinic. At age 20 months, cognitive development was measured, and at 25 months a home visit was carried out to assess maternal psychiatric status by questionnaire, and the HOME assessment was performed to assess the home environment. RESULTS: 3.9% of infants were found to have fallen below the third centile in weight for at least three months during the first year of life. Infants with failure to thrive did not differ from the general population in terms of obstetric or neonatal complications, birth order, or parents' ethnic origin, age, or years of education. The infants with failure to thrive did have lower birthweights and marginally smaller head circumferences at birth. Developmental assessment at 20 months of age showed a DQ of 99.7 v 107.2 in the matched controls, with 11.5% having a DQ below 80, as opposed to only 4.6% of the controls. No differences were found in maternal psychiatric problems as measured by a self report questionnaire. There were, however, significant differences in subscales of the HOME scale. CONCLUSIONS: (1) Infants who suffered from failure to thrive had some physiological predispositions that put them at risk; (2) failure to thrive may be an early marker of families providing suboptimal developmental stimulation.

Case-Control Studies↗
PubMed1996

Early results of infrageniculate arterial reconstruction using cryopreserved homograft saphenous conduit (CADVEIN) and combination low-dose systemic immunosuppression.

BACKGROUND: The search continues for the ideal conduit for infrageniculate arterial reconstructions when the autogenous vein is unsuitable or unavailable. Based on experimental observations in our laboratory demonstrating improvement in canine cryopreserved allograft vein patency using systemic immunosuppression (Imsup), and the remarkable clinical success achieved in older (greater than 60 years of age) solid organ transplant recipients using combination low-dose Imsup, we studied the effects of Imsup on patency of cryopreserved homograft saphenous vein (CADVEIN) used for infrageniculate arterial reconstructions. STUDY DESIGN: Under the Institutional Review Board protocol, 21 infrageniculate CADVEIN grafts were placed in 19 patients between July 1993 and August 1994 for limb salvage when autogenous veins were unavailable. An immunopharmacologic protocol consisting of low-dose cyclosporine A, azathioprine, prednisone, warfarin, aspirin, and vasodilators given orally was instituted. For various reasons, 15 patients in group 1 received Imsup; five patients never received Imsup, and one patient in group 2 received Imsup briefly. Follow-up examinations were completed using the time range of six to 18 months (mean, eight plus or minus one month). RESULTS: One patient died (5.3 percent) 30 days after emergency combined venous graft and bilateral CADVEIN bypass. The actuarial 12-month primary patency in group 1 was 59.4 percent compared with 16.7 percent in group 2 (p < 0.015, log-rank test). Cellular rejection was typically seen in explanted CADVEIN. Systemic morbidity related to Imsup was minimal. The CADVEIN morbidity rate was significant: three graft aneurysms and four early graft ruptures. Major amputations were necessary in eight of 12 patients with graft closure. CONCLUSIONS: The data suggest that Imsup significantly improves CADVEIN patency with limited systemic morbidity; however, complications related to the conduit itself occurred with greater frequency and cause greater morbidity than when the autogenous veins were used. Much has yet to be learned regarding the preservation characteristics of CADVEIN and the immunologic interactions in patients receiving CADVEIN grafts, before further clinical use of this conduit can be recommended.

Adult↗
PubMed1994

[Treatment of fever of unknown origin by homeopathy].

2 cases of fever of unknown origin (FUO) treated successfully by homeopathy are presented. The purpose is to show the effectiveness of homeopathy as adjuvant therapy for those in whom the full medical diagnostic process, assessment, and treatment are not effective. In a 12-year-old boy fever and abdominal pain persisted for several months despite various medical treatments. All symptoms disappeared following homeopathic treatment. In a 66-year-old man fever and other symptoms also disappeared after such treatment. We emphasize that homeopathy is not a substitute for the full conventional medical diagnostic investigation and treatment of FUO. Homeopathy should only be practiced by medical doctors to avoid, to the greatest extent, diagnostic and therapeutic errors.

Aged↗
PubMed1994

The distribution of BrK alpha/RbK alpha peak intensity ratio in human whole blood samples. Comparison between normal and colorectal cancer cases.

A preliminary study was conducted to compare the BrK alpha/RbK alpha peak intensity ratio in colorectal cancer (CRC) patients and healthy subjects (controls) in Israel. Blood samples were obtained from 61 CRC patients and 124 controls. The controls represent a normal population from different areas in Israel. Three hundred microliters of wet whole blood samples were analyzed by the EDXRF method. A weighted mean of 2.45 +/- 0.38 Br/Rb ratio was obtained for CRC patients, as compared with 3.28 +/- 0.40 Br/Rb ratio for controls. The mean value for controls represents only 112 subjects, since 12 individuals of the control group suffered from some other diseases and therefore were not included for the mean value calculation in this group. The results indicate that the Br/Rb ratio in CRC patients is significantly lower (p < 0.05) than in controls. No significant difference was found in Br/Rb ratio correlated to age and sex. It was not possible to draw final conclusion concerning the relationship between the Br/Rb ratio and the malignancy stage, since there was a relatively small number of cases in each stage under investigation.

Adult↗
PubMed1987

Independent study: 10-year programme review.

The Ohio State University College of Medicine has offered an independent study curricular option since 1970. This study reports our experience covering 10 entering classes and compares the independent study programme (ISP) students to the students who entered the traditional lecture-discussion programme (LDP). It looks at (a) entering demographic and personality characteristics, (b) academic, clinical and research performance during school and at graduation and (c) practice and career outcomes. The major findings are that, as groups, students from the two curricular programmes are far more alike than different but that the flexibility of an independent study programme provides special options without loss of academic achievement. Individual talents and interests were enhanced and research opportunities have aided recruitment and development of particular students. Independent study students pursued more research during medical school and hold more full-time academic positions in practice. A comparative cost study showed that, once the two programmes are operational, per student operational costs are equivalent. Results of this study indicate, that at Ohio State, the benefits of a two-track system outweigh the additional costs.

Career Choice↗
PubMed1985

A comparison of medical students' performances in independent study and traditional programs.

Medical students at Ohio State University may study the basic medical sciences in an independent study program or in a conventional lecture-discussion program. In a study involving more than 2,000 students over a 10-year period, students pursuing the independent study program and students in the more traditional program performed similarly on Part I of the National Board of Medical Examiners (NBME) examinations and in their required clerkships. However, differences were identified in some content areas and resulted in curricular changes.

Achievement↗
PubMed1984

Bilateral diaphragmatic paralysis following topical cardiac hypothermia.

Topical cardiac hypothermia has been shown to be a safe and effective means of providing protection for the ischemic myocardium during aortic cross-clamping. We report herein two cases of postoperative bilateral diaphragmatic paralysis which we believe resulted from hypothermic injury to the phrenic nerves. After open-heart surgery, both patients experienced prolonged weaning from assisted ventilation and severe orthopnea. Return of normal diaphragmatic and phrenic nerve function was demonstrated in one patient ten months after surgery. Failure to correctly interpret the respiratory failure and orthopnea led to confusion and erroneous types of therapy. Awareness of this complication should lead to improved care and postoperative management of patients.

Adult↗
PubMed1978

Idiopathic dilatation of peripheral pulmonary arteries.

We describe a patient with idiopathic dilatation of the peripheral pulmonary arteries radiologicaly mimicking pulmonary arteriovenous fistulae. Isolate involvement of the peripheral arteries in this patient supports a developmental defect in the arterial walls as the etiology.

Adult↗