Biomedical subjects
Publications and source records attributed to P Froom.
Low bone Mg concentration was found in a case of beta thalassemia associated with osteoporosis. In the absence of endocrine abnormalities and congestive heart failure, this low bone Mg suggests Mg depletion in uncomplicated beta thalassemia.
Systolic blood pressure (SBP) was measured at entry and after 12-15 years in 112 fighter pilots and compared to 112 transport and helicopter pilots. The pilots were 20-24 years old on entry into the study. Mean SBP +/- 1 S.D. on entry was 122 +/- 12 mm Hg in fighter pilots and 124 +/- 12 mm Hg in transport and helicopter pilots. After 12-15 years follow-up the mean SBP was 118 +/- 12 mm Hg in both groups. We conclude that the stress of flying fighter aircraft for 12-15 years is not associated with an increased risk of hypertension.
We evaluated T-lymphocyte functions in the peripheral blood of a patient with B-cell chronic lymphocytic leukemia after transformation to large cell lymphoma (Richter's syndrome). A subpopulation of E-rosette adherent cells were found with T-lymphocytic surface markers (OKT3+/8+/4+), monocytic characteristics (latex ingestion, nonspecific esterase staining), and suppressor activity. In contrast to the patient's nonadherent T-cells, this subpopulation suppressed PHA proliferation of autologous lymphocytes, pokeweed mitogen (PWM)-induced proliferation of normal non-T cells, and a mixed lymphocyte reaction. Further studies are warranted in patients with Richter's syndrome, in order to determine the frequency and significance of our findings.
A 45-year-old man with primary amyloidosis was initially seen with nephrotic syndrome. Factor X was found to be 5% and antithrombin III (AT III) 45% of normal plasma values. During an 11-month period, despite severe factor X deficiency, the patient did not have any bleeding complications. He developed progressive renal failure and AT III levels increased to normal, at which time he developed severe bleeding complications. These findings suggest a protective role of AT III deficiency against bleeding in a patient with severe factor X deficiency.
We tested conditioned media from 12 patients with T lymphocyte neoplasms and four T cell lines for their ability to stimulate the in vitro growth of erythroid-burst-forming units (BFU-E) from bone marrow mononuclear cells in a methylcellulose culture system. Nine patients suffered from acute lymphocytic leukemia, two from chronic lymphocytic leukemia, and one from non-Hodgkin's lymphoma. The T lymphocytes were characterized by a series of monoclonal antibodies and their stage of development was correlated with their ability to produce burst-promoting activity (BPA). Conditioned media from cells classified as prothymocytes (three cases), common thymocytes (one case), mature thymocytes (three cases), and mature lymphocytes of the helper subtype (two cases) increased BFU-E proliferation four- to 19-fold over control values using normal bone marrow as target cells. Conditioned media from OKT8+ malignant T lymphocytes (three cases) did not enhance BFU-E proliferation. Conditioned media from cells classified as immature T cells stimulated CFU-GM proliferation in only one of seven cases even though they secreted BPA. Conditioned media from three of the four cell lines stimulated by phytohemagglutinin, enhanced BFU-E growth. Our results indicate that malignant cells that have characteristics of immature T cells are able to produce BPA. Studies using techniques to isolate homogeneous populations of normal T cell subsets are required to determine whether normal immature T lymphocytes have the same capability.
The records of 1,000 asymptomatic male air force personnel were examined retrospectively for the results of 15 yearly examinations (1968 through 1983) of urinary sediment, beginning with subjects aged 18 to 33 years. The cumulative incidence of four to six or more WBCs per high-power field on one or more examinations was 31.8% after an average of 12.2 examinations per person over the 15-year period. In 107 subjects the WBCs were found on two or more occasions within five consecutive examinations. In 106 subjects, 140 urine cultures were sterile. In 28 cases the urine was also sterile after culture for Mycobacterium tuberculosis. Intravenous pyelograms, obtained in eight cases, were normal. Renal biopsy in one case with recurrent hematuria and trace proteinuria showed focal glomerulonephritis. All subjects are currently active and free of urinary symptoms an average of 7.6 years after detection of leukocyturia.
Exposure to aircraft (A/C) noise is considered to be one of the factors which causes permanent hearing threshold shifts among military aircrew. Consequently most studies, dealing with this field of evaluation, fail to focus on the contribution of other elements, especially biological (physiological) ones. We, therefore, decided to evaluate the effect of the subject's age on this process. Audiometric records of 777 aircrew members within the Israeli Air Force were examined. The average age was 27.2 +/- 5.2 years. The individual files were composed of all yearly audiograms from time of recruitment to present, personal information, recorded flight time and type of A/C flown (i.e., rotary-wing and fighter, transport and light fixed-wing aircraft). Hearing loss was studied using two criteria (a. USAF criteria; b. acoustic trauma criteria we devised). The significance of each of the factors was analysed by using uni- and multivariate analysis (Pearson correlation and stepwise multiple regression). A progressive linear correlation between age and hearing loss was exhibited (p less than 0.001). The results suggest that the age of the subject is strongly correlated with values of hearing threshold shift, while A/C type and accumulated time played a minor role.
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Thirteen cases of malignant lymphoma, exclusive of mycosis fungoides, with initial involvement of the skin, were selected from 391 consecutive patients with non-Hodgkin's lymphoma. Their clinical course was correlated to histological subtype. All patients (5/5) with 'favourable' histology had single indurated plaques without extracutaneous involvement, and remained in complete remission for at least 5 years after local radiation therapy. In contrast, all those with 'unfavourable' histology not lost to follow-up (7/7) suffered relapse or died within a 2-year period. They generally had multiple skin lesions and extracutaneous involvement at diagnosis or shortly afterwards. We conclude that histological subtype is an important variable in predicting clinical course in those with cutaneous malignant lymphoma.
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The medical records of 1000 asymptomatic male air force personnel were examined retrospectively for the results of 15 yearly examinations of urinary sediment. The study covered the period 1968-82, beginning with the subjects aged 18-33 years. The cumulative incidence of two to four or more red blood cells per high power field found at one or more examinations was 38.7% after an average of 12.2 yearly examinations per person. In 161 subjects two to four or more red blood cells per high power field were found at two or more yearly examinations within a five year period. Intravenous pyelography in 58 cases disclosed asymptomatic nephrolithiasis in six. Cystoscopy performed in 11 cases identified one patient with urethritis, one with a vesical calculus, and one with transitional cell carcinoma of the bladder. Two years before diagnosis the patient with carcinoma had had a single transient finding of 10-12 red blood cells per high power field which was not investigated further. Cystoscopy was performed after an episode of macroscopic haematuria. Renal biopsy in one subject with recurrent microhaematuria and trace proteinuria disclosed focal glomerulonephritis. None of the remaining subjects with microhaematuria developed hypertension or proteinuria, and at the end of the study period all were active and free of urinary symptoms. The observed cumulative incidence of urological neoplasms at 15 years (0.1%) was consistent with that expected in Israeli men aged 18-40 (0.09%). Hence microhaematuria detected during a screening examination probably should not be regarded as a specific sign of a significant lesion and does not of itself warrant urological investigation in adults aged 40 or less.
The erythrocyte sedimentation rate (ESR) was examined annually for 15 years in 1,000 asymptomatic men aged 18-33 years at entry into the study in 1968. The upper limit of the normal (mean + 2 SD) increased from 8 mm in the first hour in persons aged 18 years to 18 mm in those age 45. An increase in the ESR above the age adjusted upper limit of normal on at least three of four consecutive annual examinations was observed in 44 (4.4%) cases. The elevated ESR was associated with a diagnosed disorder in 10 of these 44 cases: myocardial infarctions (four), ankylosing spondylitis (three), inflammatory bowel disease (one), psoriasis (one), and "benign" monoclonal gammopathy (one). A persistently elevated ESR increased the likelihood of disease in general from 3.8% to 22.7% and of myocardial infarction from 0.7% to 9.1%. In eight patients the elevation of the ESR preceded the clinical manifestations by 2-10 years. It is concluded that a persistent moderate elevation in ESR detected in a young adult in the course of screening examinations is a risk factor for the development of disease.
Trauma to the back from the force of chronic stress is thought to be an etiologic factor in isthmic spondylolisthesis (SLL). The relationship of first degree spondylolisthesis to low back pain (LBP) is controversial. We compare the prevalence of SLL in helicopter pilots who are subject to strong vibrational forces, with other airforce personnel. Helicopter pilots had more than a four times higher prevalence of SLL (4.5%) than did cadets (1.0%) and transport pilots (0.9%). Low back pain was more frequent in pilots with SLL than in those without this lesion but in no case was the pain disabling or the defect progressive. We conclude that SLL may be induced by vibrational forces and although SLL is associated with LBP, the pain was little clinical significance.
All electrocardiograms (ECGs) from a primary care setting during a one-year period were analyzed. A total of 370 ECG tracings were recorded during 2.1 percent of patient visits. Of these tracings 62.4 percent were interpreted as normal. Only 15 different ECG diagnoses were needed to interpret 96.5 percent of the ECG tracings (97.2 percent of total diagnoses). These data can facilitate design of ECG curricula for family medicine training programs.
Systolic blood pressure (SBP) was determined annually for 12 to 15 years in 719 men, 18 to 30 years old at entry into the study. SBP values at entry were compared with those measured in the same individuals at the end of the follow-up period. The cutoff point separating "normal" from "elevated" SBP was arbitrarily set at 140 mm Hg. The highest SBP recorded at entry was 170 mm Hg. Elevated SBP on follow-up was 2.3 times more common among subjects with elevated SBP at entry. Yet, 89.2% of the subjects with elevated SBP at entry had a normal SBP on follow-up. A normal SBP at entry did not reduce the risk of elevated SBP on follow-up.
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Sewage workers are exposed to a wide range of chemicals and biological agents, including the hepatitis A virus. Inasmuch as Israel is an endemic area for hepatitis A, it is unclear if sewage workers are at increased risk for hepatitis A or which factors contribute to such risk. The authors compared seropositivity of hepatitis A in 100 sewage workers with that in 100 blue-collar worker controls. Hepatitis A seropositivity was highly prevalent, but nonsignificant, in both sewage workers and controls (82% and 91%, respectively). In sewage workers, the major risk for serological positivity was age (odds ratio = 4.5, 95% confidence interval = 1.6, 12.4 for every 10 y). The factors associated negatively with seropositivity were years of education and years of seniority. The authors concluded that exposure to sewage is not a risk factor for hepatitis A infection in Israel, and, therefore, sewage workers do not require special attention in this regard.
The authors used a mixed-effects model on a cohort of 258 randomly chosen workers in 7 fuel-distribution facilities to examine the association between airborne benzene exposure and task and timing factors. During an 8-y period, 692 repeated personal measurements were performed. Filler task, warm month, Tuesday, credit day, and time period (1992-1996) were associated significantly with higher exposures to benzene. The authors controlled for the time period, and task type strongly affected the between-worker variance; therefore, two exposure groups (i.e., fillers and nonfillers) were adequate for purposes of exposure grouping strategy. Timing factors (after controlling for task and period effects) strongly affected the high within-worker variance (> 2 than between-worker variance). Long-term exposure would be better represented if the sample was stratified by warm/nonwarm months and if measurement days were selected randomly.