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Biomedical subjects

S Hellman

Publications and source records attributed to S Hellman.

At least 19 recordsLinked to original sources
PubMed1992

Effects of noise and noise suppression on speech perception by cochlear implant users.

The recognition of phonemes in consonant-vowel-consonant words, presented in speech-shaped random noise, was measured as a function of signal to noise ratio (S/N) in 10 normally hearing adults and 10 successful adult users of the Nucleus cochlear implant. Optimal scores (measured at a S/N of +25 dB) were 98% for the average normal subject and 42% for the average implantee. Phoneme recognition threshold was defined as the S/N at which the phoneme recognition score fell to 50% of its optimal value. This threshold was -2 dB for the average normal subject and +9 dB for the average implantee. Application of a digital noise suppression algorithm (INTEL) to the mixed speech plus noise signal had no effect on the optimal phoneme recognition score of either group or on the phoneme recognition threshold of the normal group. It did, however, improve the phoneme recognition threshold of the implant group by an average of 4 to 5 dB. These findings illustrate the noise susceptibility of Nucleus cochlear implant users and suggest that single-channel digital noise reduction techniques may offer some relief from this problem.

Adult↗
PubMed1991

Thomas Hodgkin and Hodgkin's disease. Two paradigms appropriate to medicine today.

Thomas Hodgkin was an investigator whose contributions extended over a wide range of medicine. While he is known for Hodgkin's disease, this was not his major interest. That this is so has more to do with his successors than him. He had a highly committed social conscience and was outspoken in advocacy of his positions. This greatly limited his professional career. The history of Hodgkin's disease is one of hypothesis generation, which allowed for its effective treatment even without an understanding of its etiology, illustrating the approximate nature of scientific discovery and the importance of chance in historical attribution. Hodgkin, as a scientist, healer, and socially committed individual, embodied the many characteristics that are desirable for today's physician, while the evolution of knowledge about Hodgkin's disease and its treatment is an instructive model for future medical advances.

England↗
PubMed1991

Reviewing graduate medical education programs: a cancer center experience. Members of the Graduate Training Committee.

The Graduate Training Committee at Memorial Sloan-Kettering Cancer Center developed procedures for comprehensively reviewing the 32 graduate training programs at our institution. The methods used to carry out this review, the problems encountered, and the results of this review are presented. As this type of program review is now mandated by the Accreditation Council for Graduate Medical Education (ACGME), our method and experience should prove useful to other institutions planning a similar review process.

Cancer Care Facilities↗
PubMed1991

The intellectual quarantine of American medicine.

Powerful forces, which are increasing in number and intensity, are causing unexpected changes in medicine. The biological revolution offers opportunities for intervention of a magnitude unknown previously, while at the same time, society is concerned with the increasing costs of medical care. Access to such care and its equitable distribution are the subject of public debate. All of these are issues for ethical consideration. With so many forces acting, there is the opportunity for both effective change and catastrophe. Medicine must be studied in the whole university where such forces can be considered in an appropriate scholarly fashion with the perspective of history and the methodology of the many academic disciplines. Multidisciplinary units within the university must be formed to consider the complicated issues and the consequences of suggested courses of action. Surely this is better than the advocacy positions of the various parts of organized medicine, regulatory bodies, or insurance companies. Medicine must return from the often intellectually and geographically separated medical school to the center of the university's intellectual life.

Costs and Cost Analysis↗
PubMed1991

Passive smoking among schoolchildren in Israel.

A health survey was carried out among 8259 second- and fifth-grade schoolchildren living in three towns along the Israeli coast. The schoolchildren performed the following pulmonary function tests: forced vital capacity, forced expiratory volume in 1 sec, and peak expiratory flow, their parents filled out an American Thoracic Society-National Heart and Lung Institute health questionnaire. The aim of the survey was to study the impact of environmental and home exposures on the prevalence of respiratory conditions and on pulmonary function tests among Israeli schoolchildren. The health effects of exposure to passive smoking are discussed in detail. A trend of a higher frequency of reported respiratory conditions was found among schoolchildren whose fathers or mothers are smokers compared with children whose parents do not smoke. A statistically significant excess between 1.4% (for wheezing without cold) and 4.7% (for cough with cold) was found for children of smoking fathers; the excess for children of smoking mothers was between 1.6% (for wheezing with cold) and 3.6% (for cough with cold) compared with children of nonsmokers. A gradual excess in symptoms was found among children with none, one, and two smoking parents. Relative risks were found to be between 1.13 (for bronchitis) and 1.28 (for wheezing without cold) for children of smoking fathers, and between 1.24 (for asthma) and 1.41 (for cough with sputum) for children of smoking mothers, compared with 1.00 for children of nonsmokers. There was no consistent trend of reduced pulmonary function tests among children of smokers compared with nonsmokers' children.

Child↗
PubMed1990

Prevalence of respiratory conditions among schoolchildren exposed to different levels of air pollutants in the Haifa Bay area, Israel.

During spring 1984, 2334 second and 2000 fifth-grade schoolchildren living in three Haifa Bay areas on the eastern Mediterranean coast with different levels of air pollution were studied. The parents of these children filled out American Thoracic Society and National Heart and Lung Institute health questionnaires, and the children performed the following pulmonary function tests (PFT); FVC, FEV1, FEV1/FEV, PEF, FEF50, and FEF75. A trend of higher prevalence of most reported respiratory symptoms was found for schoolchildren growing up in the medium and high pollution areas as compared with the low pollution area. Part of the reported respiratory diseases were significantly more common among children from the high pollution area. Models fitted for the respiratory conditions that differed significantly among the three areas of residence also included background variables that could be responsible for these differences. Relative risk values, which were calculated from the logistic models, were in the range of 1.38 for sputum with cold and 1.81 for sputum without cold for children from the high pollution area as compared with 1.00 for children from the low pollution area. All the measured values of PFT were within the normal range. There was no consistent trend of reduced pulmonary function that characterized any residential area.

Air Pollutants↗
PubMed1989

Loss of hematopoietic stem cell self-renewal after bone marrow transplantation.

The quality of long-term hematopoietic engraftment after bone marrow transplantation (BMT) has not been well characterized. Clinical autologous BMT involves removal of less than 5% of the total content of the recipient marrow followed by ablation of the remaining marrow and reinfusion. To study long-term consequences of transplanting limited numbers of BM stem cells further, we evaluated the hematopoietic reserve in recipient animals after transplantation of varying quantities of BM. Recipient animals demonstrated a donor BM cell dose-dependent decrease in stem cell content and self-renewal capacity that was not reflected in peripheral blood (PB) counts or BM cellularity. This decrease was observed after initial BM recovery and did not change with time after transplantation, demonstrating a permanent loss in BM self-renewal capacity. In addition, animals alive at 3 months, a time selected to allow BM recovery, also demonstrated a donor BM cell dose-dependent decrease in survival at 1 year. These results emphasize the importance of optimizing stem cell number in BMT.

Animals↗
PubMed1989

Late tissue-specific toxicity of total body irradiation and busulfan in a murine bone marrow transplant model.

Total body irradiation (TBI) and busulfan were compared for late effects in a murine model of bone marrow transplantation (BMT). Male C57BL/6 mice were given fractionated TBI or busulfan given in 4 equal daily doses followed by infusion of 10(7) syngeneic bone marrow cells. Total doses of 16.4 Gy TBI and 3.4 mg busulfan were chosen for their equivalence in inducing near complete engraftment of allogeneic marrow from donor mice of the LP strain. The two treatment groups had a late wave of mortality starting at about 80 weeks after transplantation. Specific tissue damage was manifested in bone marrow stem cells, splenic T-cell precursors, hair greying and cataract formation for both TBI and busulfan but to varying degrees. Severe nephrotoxicity and anemia were observed only after TBI. Although both busulfan and TBI kill early marrow stem cells and are effective preparative agents in bone marrow transplantation, their effects on other stem cell and organ systems are not similar. In addition, many of the injuries seen are late to occur. The delayed expression of injury deserves careful long-term evaluation of BMT recipients before the therapeutic potential of effective preparative regimens can be fully appreciated.

Animals↗
PubMed1989

Nonmammary malignant neoplasms in patients with stage I (T1N0M0) and stage II (T1N1M0) breast carcinoma. A long-term follow-up study.

We have recently updated the follow-up of 644 women with pathologically determined Stage I (T1N0M0) (474 patients) and Stage II (T1N1M0) (170 patients) breast carcinoma treated by modified or radical mastectomy from 1964 through 1970 at Memorial Sloan-Kettering Cancer Center. Median follow-up was 18.2 years with over 90% of surviving patients followed for 15.7 years. Recurrences occurred in 166 (26%) with 148 (23%) dead of disease and 18 (3%) alive with recurrence when last seen. A nonmammary malignant neoplasm (NMMN) was confirmed in 86 (13%) of the 644 patients. Of these, 55/86 (64%) were diagnosed after and 27 (32%) were diagnosed before the breast carcinoma. Four patients (5%) had a NMMN before and after the breast carcinoma. The most frequent sites of prior carcinoma were the cervix (n = 8), colon-rectum (n = 7), and oropharynx (n = 5), whereas the more common locations of subsequent NMMN were the ovary (n = 11), colon-rectum (n = 10), lung (n = 9), stomach (n = 6), and lymphoma-leukemia (n = 5). There was not a statistically significant difference in the frequency of subsequent NMMN when patients who received adjuvant radiation were compared with those who received adjuvant thiotepa or no adjuvant therapy. There was no excess of lymphoma or of other NMMN in the treated region or of contralateral breast carcinoma among adjuvant radiation treated patients. The overall hazard rate for subsequent NMMN was 7/1.000 women at risk per year. The risk was fairly stable over the first 15 years of follow-up but rose to 12/1,000 in the 15-20-year period. The observed frequency and time distribution of NMMN were very similar to the expected frequency determined by comparison with a population of age-matched women. Most fatal NMMN arose in the ovaries, stomach, women. Most fatal NMMN arose in the ovaries, stomach, pancreas, and lungs. There were 35 deaths due to NMMN detected subsequent to the diagnosis of breast carcinoma (15% of all cancer deaths and 64% of 55 subsequent NMMN). In this series, subsequent NMMN were as frequent as contralateral breast carcinoma, and they were responsible for seven times more deaths. Hence, an important goal of any follow-up program for breast cancer patients should be the early detection and treatment of NMMN.

Breast Neoplasms↗
PubMed1989

A long-term follow-up study of survival in stage I (T1N0M0) and stage II (T1N1M0) breast carcinoma.

This study was undertaken to investigate the long-term survival and the probability of "cure" in a group of 644 patients treated by mastectomy for T1 breast carcinoma. After a median follow-up of 18.2 years, 23% were dead of recurrent breast carcinoma, 3% were alive with recurrent disease, and 74% had not experienced a recurrence. The probability of recurrence was directly related to the initial extent of the disease. Overall, 16% of recurrences and 25% of deaths due to disease occurred in the second decade of follow-up. The proportion of recurrences detected in the second decade was inversely related to the stage of the primary tumor at diagnosis. When stratified by tumor size, T1N0M0 patients with tumors 1.0 cm or less in diameter had a significantly better 20-year recurrence-free survival (86%) than did T1N0M0 patients with tumors 1.1 to 2.0 cm (69%). When observed and expected survival curves were compared by the method of Brinkley and Haybittle, it appeared that 80% of T1N0M0 patients with tumors 1 cm or less might be cured at 20 years, whereas for those in the 1.1- to 2-cm group, the proportion cured was indeterminate, but might be as high as 70%. A potentially cured group could not be identified among T1N1M0 patients, but an estimated 52% of these patients did not have a recurrence within the nearly 20-year follow-up period. These data are important when one considers the proper role of adjuvant therapy for stage I disease. Patients with tumors larger than 1 cm and those with axillary lymph node metastases may have an improved recurrence-free survival as a result of systemic adjuvant treatment, while women in the T1N0M0 group with an especially favorable recurrence-free survival, particularly those with tumors 1 cm in diameter or smaller, might be spared adjuvant therapy.

Breast Neoplasms↗
PubMed1989

Pathological prognostic factors in stage I (T1N0M0) and stage II (T1N1M0) breast carcinoma: a study of 644 patients with median follow-up of 18 years.

Prognostic factors have been examined in 644 patients with tumor-node-metastasis (TNM) stage T1 breast carcinoma treated by mastectomy and followed for a median of 18.2 years. Overall, 148 patients (23%) died of recurrent breast carcinoma. Eighteen (3%) were alive with recurrent disease and 478 (74%) were alive or died of other causes without recurrence. Unfavorable clinicopathologic features were larger tumor size (1.1 to 2.0 cm v less than or equal to 1 cm), perimenopausal menstrual status, the number of axillary lymph node metastases, poorly differentiated grade, presence of lymphatic tumor emboli (LI) in breast tissue near the primary tumor, blood vessel invasion (BVI), and an intense lymphoplasmacytic reaction around the tumor. Median survival after recurrence for the entire series was 2 years. This was not significantly influenced by tumor size, the number of axillary nodal metastases, the type of treatment for recurrence, or the interval to recurrence. The proportions surviving 5 and 10 years after recurrence were 17% and 5%, respectively. Among T1N0M0 cases, the chance of a local recurrence was 2.8% within 20 years. Median survival of T1N0M0 cases after local recurrence (4.5 years) was significantly longer than after systemic recurrence (1.5 years). A similar trend (3.7 v 2.0 years), not statistically significant, was seen in T1N1M0 patients, who had a 6.5% chance of local recurrence within 20 years. Median survival following systemic recurrence detected 10 or more years after diagnosis in T1N0M0 and in T1N1M0 patients was significantly longer than the median survival for systemic recurrences found in the first decade of follow-up. This difference did not apply following local recurrence in either T1N0M0 or T1N1M0 cases. It is evident that patients with T1 breast carcinoma can be subdivided into differing prognostic groups and this must be taken into account when considering the role of adjuvant chemotherapy for stage I disease. Systemic adjuvant treatment may prove to be beneficial for patients with unfavorable prognostic factors, while women with an especially low risk for recurrence (eg, T1N0M0 tumor 1.0 cm or less) might be spared such treatment.

Breast Neoplasms↗
PubMed1989

Stem cell self-renewal considerations in bone marrow transplantation.

Autologous bone marrow transplantation is being used for an increasing number of patients with malignant diseases including Hodgkin's disease, non-Hodgkin's lymphomas, and leukemia. As the success of this procedure improves, there will be continuing concern for the consequences of such treatment. One such concern is the long-term hematopoietic function of recipients following marrow transplantation. There is evidence that bone marrow stem cells are limited in self-renewal capacity. Under circumstances of exposure to certain cytotoxic agents or to great proliferative stress, and following transplantation of marrow into lethally irradiated recipients, bone marrow stem cells undergo a permanent loss of self-renewal capacity. This loss is not initially reflected in peripheral blood counts or in marrow cellularity, but can be determined by a decrease in marrow stem cell content and by assays measuring self renewal. Animal work suggests that survival may be decreased following this loss in self-renewal. In order to limit the adverse effect of this phenomenon, efforts should be made to optimize both the quantity and quality of donor marrow engrafted. This should be possible by transplanting the largest number of marrow cells feasible, and by avoiding prior exposure to cytotoxic agents that are known to damage early stem cells in those patients who are possible candidates for autologous marrow transplantation. The use of lymphokines and peripheral stem cell harvests in transplantation should be carefully monitored as self renewal of engrafted marrow may also be decreased following these new techniques.

Animals↗
PubMed1989

Contralateral breast carcinoma: an assessment of risk and prognosis in stage I (T1N0M0) and stage II (T1N1M0) patients with 20-year follow-up.

Among 644 patients with a small (T1) primary breast carcinoma who were followed up for a median of 18.2 years, subsequent contralateral breast carcinomas were detected in 57 of 610 women (9%) who had a contralateral breast at risk. The average annual hazard rate for contralateral carcinomas was 8/1000 patients at risk per year without significant fluctuations throughout the 20 years of follow-up. Recurrences were caused by 9 of 57 (16%) subsequent contralateral carcinomas, and 4 of the 57 patients (7%) died of recurrent contralateral carcinomas. Contralateral carcinomas were responsible for 5.1% (9 of 176) of all recurrences of breast carcinomas and 2.6% (4 of 153) of breast carcinoma deaths. Surveillance of the contralateral breast must continue throughout a patient's lifetime. Detection and treatment of subsequent lesions at an early stage is a beneficial result of follow-up, especially in women whose first carcinoma is likely to have been cured.

Age Factors↗