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Biomedical subjects

M Alkan

Publications and source records attributed to M Alkan.

At least 37 records · Page 2Linked to original sources
PubMed2000

Determination of acidity constants of acid-base indicators by second-derivative spectrophotometry.

A method for calculation of acid-base dissociation constants of monoprotic weak organic acids whose acid and base species have overlapping spectra from absorptiometric and pH measurements is described. It has been shown that the second-derivative spectrophotometry can effectively be used for determining the dissociation constants, when dissociation constants obtained for methyl orange and bromothymol blue were compared with the values given in the literature.

Azo Compounds↗
PubMed1999

Massive pulmonary haemorrhage caused by leptospirosis successfully treated with nitric oxide inhalation and haemofiltration.

A patient with leptospirosis who developed oliguric renal failure, massive pulmonary haemorrhage and respiratory failure is described. The patient's clinical condition and arterial oxygenation failed to improve despite vigorous supportive measures. Nitric oxide inhalation and haemofiltration resulted in a marked clinical improvement and subsequent full recovery. We suggest that the addition of haemofiltration and nitric oxide inhalation therapy should be considered in patients with pulmonary haemorrhage and renal failure caused by leptospirosis, in whom conventional therapy fails.

Administration, Inhalation↗
PubMed1999

Rett syndrome and genetic drift.

An X chromosome gene is assumed to be responsible for the cause of Rett syndrome (RS). However, new genealogical observations suggest involvement of autosomal recessive gene(s) as well, at least in familial cases. To account for these and other recent observations, the theoretical model presented in 1990 by the authors of this paper is applied to the calculation of gene frequencies. Observed frequencies of sporadic and familial cases of RS are used, taking into account genetic drift in inbreeded areas. Moreover, an attempt is made to use the proportion of RS variants in familial and sporadic cases for the explanation of so called 'formes frustes', and as evidence for the existence of female as well as male carriers. The estimated frequency of the recessive autosome mutation, or possibly a frequent polymorphism, is 22.5%.

Alleles↗
PubMed1998

Surface Titrations of Perlite Suspensions.

The surface charge behaviour of unexpanded and expanded perlite samples in KNO3 and NaCl solutions were investigated as a function of pH and ionic strength. The solutions of KNO3 and NaCl ranging from 10(-3) to 1.0 M were used. The potentiometric titration method was used to determine the surface charge of perlite samples. It was confirmed that the perlite samples had no the point of zero charge and was negatively charged in the pH range of 3-10. The double extrapolation method was used for determining the intrinsic equilibrium constants for simple ionization and complex ionization reactions. The values obtained are pKinta2 = 2.5 and p*KintK+ = 2.3 in KNO3 solutions and pKinta2 = 3.0 and p*KintNa+ = 2.4 in NaCl solutions for unexpanded perlite, and pKinta2 = 2.6 and p*KintK+ = 2.4 in KNO3 solutions and pKinta2 = 2.7 and pKintNa+ = 2.4 in NaCl solutions for expanded perlite. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Antibodies to mycoplasma fermentans in HIV-positive heterosexual patients: seroprevalence and association with AIDS.

There are conflicting reports concerning the prevalence of Mycoplasma fermentans in HIV-positive patients and its association with AIDS. Serum antibodies to M. fermentans were measured by a modified immunoblotting technique in 48 HIV-positive heterosexual patients and in 30 HIV-negative heterosexual controls. Antibodies to M. fermentans were detected in 19 (40%) of HIV-positive patients and in three (10%) of the HIV-negative controls (P = 0.01). The prevalence of antibodies to Mycoplasma hominis and to Ureaplasma urealyticum was similar in both groups. In the HIV-positive group, 16/19 (84%) M. fermentans-positive patients developed AIDS, compared to eight of 29 (28%) M. fermentans-negative patients (P = 0.0004). The HIV-positive patients with antibodies to M. fermentans had a lower CD4+ cell count and a higher prevalence of antibodies to the other mycoplasma tested (P = 0.007 and P = 0.03, respectively), as compared to the patients without antibodies to M. fermentans. These findings may suggest that the presence of antibodies to M. fermentans indicate an opportunistic infection. Of the 19 M. fermentans-positive patients, 11 were positive on the first examination, and eight became positive during the follow-up period. Seven out of these eight patients developed antibodies to M. fermentans before the development of AIDS. Therefore, the possibility exists that M. fermentans might influence the development of AIDS.

AIDS-Related Opportunistic Infections↗
PubMed1998

Imported severe falciparum malaria in Israel.

Malaria remains an overwhelming problem in tropical developing countries, with 300 to 500 million new cases and 1.5 to 3.5 million deaths per year. Malaria is a potentially life-threatening disease for travelers to the tropics. Imported malaria is an important clinical problem in nonendemic areas of the world because of increasing numbers of travelers, overseas workers, and immigrants from endemic areas. According to the World Health Organization's criteria, the recognition of one or more of the following clinical features should raise the suspicion of severe malaria: cerebral malaria (unrousable coma), severe anemia (hemoglobin <5 g/dL), renal failure (serum creatinine >3 mg/dL), pulmonary edema or adult respiratory distress syndrome, hypoglycemia (glucose <40 mg/dL), circulatory collapse or shock, disseminated intravascular coagulation, repeated generalized convulsions, acidosis (pH <7.25), macroscopic hemoglobinuria, hyperparasitemia (>5 percent of the erythrocytes infested by parasites), or jaundice (bilirubin >3 mg/dL). Although only a small proportion of patients with malaria develops severe manifestations, these patients require the most urgent and intensive care. Mortality among patients with cerebral malaria, even when treated in modern intensive care units, exceeds 30%, and when complicated by the adult respiratory distress syndrome, it may approach 80%. Among travelers, mortality remains a serious issue because of failure to obtain and use preventive measures, delay in seeking medical attention, and misdiagnosis.

Adult↗
PubMed1998

Schistosomiasis presenting as acute appendicitis in a traveler.

Schistosomiasis, a waterborne trematode infestation, is one of the most widespread parasitic diseases in the world. It occurs in well-defined endemic geographical areas. Schistosomiasis of the appendix was first described by Turner in 1909, and has been reported from endemic areas. However, appendicular schistosomiasis in travelers has not been reported in the English literature. We describe an Israeli traveler with acute appendicitis as the presenting symptom of schistosomiasis, 2 years after a visit to Africa.

Acute Disease↗
PubMed1997

Impaired neutrophil functions in patients with leukocytoclastic vasculitis.

BACKGROUND: Leukocytoclastic vasculitis (LV) is characterized by segmental inflammation of small blood vessels, resulting in ischemic damage to the surrounding tissue. It is considered to be related to a type III hypersensitivity reaction, although the exact etiologic mechanism is not clear. OBJECTIVE: The purpose of this study was to evaluate neutrophil functions in patients with LV in order to understand their role in the pathogenesis of the disease. METHODS: Neutrophil functions were examined in 25 LV patients. The patients were divided into two groups: Group A consisted of 14 patients with drug-induced LV and Group B consisted of 11 patients where LV was induced by other factors. RESULTS: Both groups of patients showed significantly reduced chemotaxis and phagocytosis. Superoxide generation was significantly lower (P < 0.001) only in neutrophils from patients in Group A: 5.8 +/- 0.5 nmoles O2/10(6) cells/min compared to 9.08 +/- 0.8 nmoles O2/10(6) cells/min in the controls. Preincubation on normal neutrophils with the patients' sera caused an increase in their superoxide generation in accordance with the high IL-8 levels in these sera. CONCLUSIONS: Neutrophil functions were significantly impaired in patients with LV. It is likely that factors present in LV plasma may chronically activate neutrophils, so that they become refractory to further stimulation. Our study showed that neutrophil superoxide generation is low only in drug-induced LV; this test may assist in distinguishing such patients from those with LV induced by other causes.

Acetaminophen↗
PubMed1997

Pleural empyema caused by Leuconostoc spp.

A rare case of pleural empyema caused by Leuconostoc spp. is reported. The patient was treated successfully with clindamycin. To our knowledge this is the first reported case of pleural empyema caused by Leuconostoc spp. In a patient with characteristic predisposing factors, such as a serious underlying disease, previous vancomycin therapy and thoracic access device. Our case illustrates that Leuconostoc spp. can cause pleural infection as further evidence of its human pathogenicity.

Anti-Bacterial Agents↗
PubMed1996

'Travelers' thyrotoxicosis'. Transitory thyrotoxicosis induced by iodinated preparations for water purification.

Two young adults presented with thyrotoxicosis after increased iodide ingestion in the course of backpacking trips to Central and South America, during which each of them used an iodinated preparation for water purification. In both cases, serologic tests were positive for antithyroid peroxidase antibodies, and one had a family history of immune thyroid disease. We suggest that in these two cases the condition was a variant of iodide-induced thyrotoxicosis, reflecting an inadequate response to iodide excess in association with a presumed preexisting asymptomatic immune thyroid disease. This observation adds a new consideration for travelers' consultation.

Adult↗
PubMed1995

Streptococcal group C bacteremia. Survey in Israel and analytic review.

BACKGROUND: Data concerning group C streptococcal bacteremia come mainly from case reports; thus, population-based studies from different geographic areas are needed to validate these findings. METHODS: Eight years of data on group C streptococcal infection in Israel and cases of bacteremia in five hospitals were reviewed. We compared data from our survey as well as from other population-based studies with multiple cases published as case reports. RESULTS: The organisms were isolated in 78 cases (excluding pharyngitis); 16 had bacteremia. Ten cases of bacteremia were reviewed in five hospitals; none of the patients reported exposure to animals, and nine had severe underlying diseases. The clinical syndromes included four cases of primary bacteremia, four cutaneous infections, and one case each of meningitis and pneumonia. There were two deaths, one patient underwent amputation of a toe, one had a stroke, and one had a relapse. We compared 80 cases published as case reports with 59 cases reported in five population-based studies from different countries. We found higher rates of underlying diseases, alcohol abuse, liver diseases, and cutaneous infections, and lower rates of exposure to animals or raw products, endovascular infections, and central nervous system infections in population-based studies. Morbidity and mortality were 20% to 30% each in both types of studies. CONCLUSIONS: Group C streptococcal bacteremia affects patients with underlying diseases; exposure to animals is variable and less frequent than previously reported. Morbidity and mortality are high and probably reflect the patients' underlying state as well as the severity of the infection.

Adolescent↗
PubMed1995

Musculoskeletal manifestations of brucellosis: a study of 90 cases in Israel.

Rheumatological manifestations are frequently reported in patients with brucellosis. In a retrospective study of 90 patients diagnosed with brucellosis over a period of 18 years, 83 (92%) patients were Bedouins, 55 of whom (61%) reported ingestion of unpasteurized goat milk and goat milk products. The male/female ratio was 1:1, and the adult to child ratio was 3:2. The mean age of the patients was 25 years (range, 1-72 years). Rheumatological manifestations (myalgia, arthralgia, and arthritis) were reported in more than half of the patients. These manifestations started on days 3 and 4 of the disease and were mild to moderate in severity. Myalagia was evident in 49 (54%) patients and was more common in adults than in children (67% versus 37%; P < .01) and in men (67%) than in women (42%; P < .01). Arthralgia was the most common musculoskeletal manifestation, found in 55 (61%) patients, and occurred more often in children than in adults (74% versus 52%; P < .05). Arthritis was detected in 37 (41%) patients. The hip and knee joints were the most common sites of arthritis (31% each) followed by sacroiliac involvement (17%) and shoulder or spine involvement (5% each). Arthritis was also more common in children (63% versus 29%; P < .01). The prevalence of arthritis was similar in men and women. Cure was achieved in all patients after antibiotic therapy.

Adolescent↗
PubMed1995

[A national qualifying internal medicine examination for Israeli medical students].

In 1991 the deans of the 4 medical schools in Israel decided to institute a national qualifying examination in internal medicine. This marked the beginning of the process of unifying the qualifying examinations in all major medical fields. We describe the development of the examination, experience with its administration to 720 students in 1992-1994, and the outcome of this initial effort. The examinations were prepared by a committee of senior faculty from the 4 schools, representing all the relevant clinical areas. Professional consultation was provided by the Unit for Medical Education of Tel Aviv University. Each examination consisted of 180 multiple choice items, reflecting an agreed representation of the various medical specialties, and was designed to test both comprehension and problem-solving ability. A syllabus was published by the committee and distributed to students and faculty in preparation for the examination. In composing the examination, the committee took into consideration differences in general policy and varying emphases in the curricula of the 4 schools. Analysis of the results of the 3 annual examinations showed both a high level of reliability and high quality of the majority of the individual test items. There was a trend with time to slightly lower average scores, and fewer passed the exam last year. There was improvement in the results after the first 2 years in the area of problem-solving related to interpretation of imaging, blood smears and clinical photographs, but this trend did not continue into 1994. The introduction of a high level examination based on a common syllabus provided important feedback, improving both student motivation and clinical teaching. For all schools, the outcome of the examination served as an important external indicator of teaching standards. Following this positive experience, uniform examinations in surgical subjects and pediatrics were introduced for the first time in 1993. The committee recommends that Israeli medical schools gradually introduce a comprehensive qualifying examination based on a mutually agreed list of objectives and syllabus.

Educational Measurement↗
PubMed1994

Immigration of Ethiopians with typhoid fever to Israel: apparent lack of influence on the local population.

The epidemiology of typhoid fever in Western countries may be affected by immigration from developing countries. We studied the immigration of Ethiopian Jews to Israel to find the effects of an influx of many individuals infected with typhoid into an area with a low incidence of the disease. Typhoid fever affected 204 Israelis and 121 (1.1%) of 10,654 Ethiopian immigrants during the period of 1984-1985. Of those Ethiopian cases, 107 occurred during a 3-month period. During the 5 months following that 3-month period, there was no increase in the number of cases of typhoid among Israelis. Although after that time there was a local waterborne outbreak of typhoid that affected 83 Israelis, no Ethiopians resided in the area where the outbreak occurred; therefore, we concluded that these 83 cases of typhoid fever were not related to the immigration of Ethiopians into Israel. In fact, if those 83 cases were excluded from the statistical analysis, there was no increase in the occurrence of typhoid during the 2-year period studied. Therefore, the immigration of many people with typhoid into an area of low incidence does not necessarily confer a risk of infection to the local population.

Emigration and Immigration↗
PubMed1994

Superoxide production by neutrophils from trauma patients: regulation of NADPH oxidase activity.

The production of free oxygen radicals by polymorphonuclear cells (PMNs) was studied in 25 patients after blunt trauma. Superoxide generation significantly increased immediately after trauma and returned to normal soon after the event. Patients were subsequently divided into two groups: those who developed sepsis and those who did not develop infectious complications. Superoxide production by intact PMNs following stimulation by three different stimulants was initially not different in trauma patients who developed sepsis. Follow-up showed an increase in superoxide production when infection complicated the course of trauma patients. Further studies were performed in a cell-free system containing cell membranes and cytosol from patients or healthy controls. No difference in the production of superoxide was found when membranes from trauma patients or controls were mixed with cytosols from controls. When cytosols from patients were mixed with membranes from controls, a significant increase in superoxide production was observed in the group that developed sepsis. Immunoblotting analysis of two protein components of the cytosolic portion of the NADPH oxidase, p47 and p67, were done. The increase in quantity of p47 correlated with the increase in superoxide production during sepsis, and thus may be the major contributor to the high activity.

Adolescent↗
PubMed1994

An outbreak of foodborne streptococcal throat infection.

Streptococcal pharyngitis is a common disease of epidemic nature, usually transmitted by saliva droplets. We present an epidemiologic analysis of an outbreak of streptococcal pharyngitis in a military unit involving 75 soldiers. The causing organism was Streptococcus pyogenes (group A beta hemolytic Streptococcus, T28 M56), which was isolated from 53 affected individuals. The source of the epidemic was probably an army cook. The infection was transferred by a cabbage salad to individuals who became symptomatic within 24-48 h. This epidemic is a reminder of an exceptional route of streptococcal dissemination and one of the largest outbreaks of foodborne streptococcal pharyngitis documented.

Disease Outbreaks↗