Search PubMed⌕ Search

Biomedical subjects

P Froom

Publications and source records attributed to P Froom.

At least 109 records · Page 6Linked to original sources
PubMed1988

T-cells of multiple myeloma patients triggered by the autologous mixed lymphocyte reaction suppress polyclonal immunoglobulin synthesis.

To elucidate the possible role of T-cells of patients with multiple myeloma (MM) in the suppression of polyclonal immunoglobulin synthesis. T-cells with and without prior activation by the autologous mixed lymphocyte reaction (AMLR) were added to normal immunoglobulin (Ig)-secreting cultures. The suppression induced by AMLR-activated T-cells from patients with MM was compared to that induced by AMLR-activated T-cells from apparently normal controls. The addition of 10% unstimulated autologous T-cells from patients with MM resulted in minimal suppression of IgG synthesis (87 +/- 19% of baseline values for patients and 115 +/- 21% for controls, no significant difference). The suppression sharply increased when T-cells were preactivated by AMLR and then added in the same concentration to the IgG-secreting cultures (38 + 12% of baseline values for patients compared to 106 + 14% for controls, P less than 0.05). AMLR cultures were performed in the presence of adherent monocytes and after their depletion. The T-cell suppressor effect on normal IgG synthesis was unchanged after monocyte depletion. T-cells preactivated in the AMLR from patients with MM sharply suppress in vitro polyclonal IgG synthesis, and the activation of these suppressor T-cells is not dependent on the presence of monocytes.

Aged↗
PubMed1988

Isolated tricuspid valve prolapse.

Tricuspid valve prolapse is commonly associated with mitral valve prolapse or other heart abnormalities and is rarely found as an isolated finding. A patient with isolated tricuspid valve prolapse is described which was discovered on routine examination of an asymptomatic pilot.

Adult↗
PubMed1988

T-cell acute lymphoblastic leukemia with severe leukopenia: evidence for suppression of myeloid progenitor cells by leukemic blasts.

A patient with T-cell acute lymphoblastic leukemia presented with leukopenia due to neutropenia, no circulating blasts and normal hemoglobin level. Marrow leukemic T lymphoblasts inhibited in vitro normal CFU-GM colony growth and released an activity that stimulated normal BFU-E growth. This patient demonstrates that immature T cells may modify hematopoietic stem cell growth both in vitro and in vivo.

Adult↗
PubMed1988

Impaired autologous mixed lymphocyte reaction (AMLR) in patients with ataxia-telangiectasia and their family members.

We used the autologous mixed lymphocyte reaction (AMLR) to test T cell function in four patients with Ataxia-telangiectasia (AT), in 11 first-degree relatives and in 20 controls. There was a marked reduction of AMLR in the patients and in three relatives compared to the age-matched controls. In the AT patients the defect in AMLR was intrinsic to the CD4 subpopulation, since exogenous IL-2 did not improve the response of isolated CD4 cells. In contrast to normal controls, pre-incubation of autologous B cells with Epstein-Barr virus (EBV) did not enhance the reduced AMLR in the AT patients and the three first-degree relatives. We conclude that in both patients with AT and in some of their family members there is an intrinsic defect in CD4 T cells. This defect leads to diminished reactivity to EBV infected autologous B cells, and may explain in part the high incidence of malignancies observed in such families.

Ataxia Telangiectasia↗
PubMed1988

Discordant effect of interferon on natural killer activity and tumor cell sensitivity to lysis in hairy cell leukemia.

We studied the action of alpha-interferon (IFN) and interleukin-2 (IL-2) on natural killer (NK)-rich fractions and autologous tumor cells from two patients with hairy cell leukemia (HCL). The addition of IFN or IL-2 to the NK-rich fractions resulted in a significant increase in NK activity against the autologous tumor cells. This stimulatory effect was blocked if the target hairy cells (HCs) were preincubated with either IFN or IL-2. Pretreatment of the HCs with anti-Tac antibody entirely prevented the blocking effect of IL-2 and partially the blocking effect of IFN. One patient was treated with recombinant alpha c-IFN. After 2 months there was a dramatic reduction in the number of HCs in the peripheral blood coincident with the loss of the protection effect of IFN against NK lysis of the patient's HCs. NK activity against autologous tumor cells correlated poorly with that against the K562 cell line. We conclude that there is a discordant effect of IFN and IL-2 on NK activity and HC sensitivity to lysis. The Tac receptor appears to play a role in this sensitivity. Caution should be exercised in extrapolating the effects of NK activity against K562 cells to those on HC targets.

Antineoplastic Agents↗
PubMed1988

Aircrew selection: a prospective study.

The medical reasons for rejection among 3,000 consecutive applicants for flight training were evaluated, and the effectiveness of the screening process determined by reviewing subsequent medical wastage occurring during flight training. Of the 46 cadets who left the course because of medical reasons, 8 withheld information which would have led to their rejection on the original screening examination (epilepsy 1, recurrent syncope 1, migraine headache 2, Crohn's disease 1, asthma 1, chronic knee pain 1, and chronic recurrent headaches 1). There were also two errors in medical processing. The other 36 cases could not have been predicted by current screening procedures. We conclude that the major deficiency in our screening process is the concealment or withholding of information by candidates for flight training.

Adult↗
PubMed1988

Air accidents, pilot experience, and disease-related inflight sudden incapacitation.

The epidemiology of sudden death, the etiology of inflight sudden incapacitation, and the influence of pilot age and experience on air accident rates are reviewed in order to determine the aeromedical emphasis needed to minimize accidents. Sudden deaths in men over age 35 are nearly all due to coronary artery disease, whereas in those under 35 years they are mostly due to hypertrophic cardiomyopathy. The incidence of fatal accidents from human error is, however, far greater than that from physical illness. Since inexperienced pilots have a 2-3 times increased incidence of mishaps due to pilot error, the estimated risk of disease related in-flight sudden incapacitation should be balanced by consideration of pilot experience. Therefore, it may be preferable to grant waivers to experienced pilots with an increased incidence of disease-related inflight sudden incapacitation than to replace them with novices. We conclude that overly strict medical criteria may paradoxically increase accident rates.

Accidents, Aviation↗
PubMed1988

Bone marrow biopsy in multiple myeloma: a clinical pathological study.

Forty-two bone marrow aspirates and biopsies during follow-up examinations from patients with multiple myeloma were reviewed to determine whether the results correlate with the clinical state of the patient at the time of examination. The percentage of plasma cells on biopsy and aspiration, cytological immaturity, patterns of plasma cell infiltration, and the presence or absence of multiple lymphoid nodules and marked fibrosis were cross-tabulated with clinical parameters (hemoglobin levels, osteolytic lesions, and renal function). Hemoglobin levels less than 10 g/dl were more frequent in those with greater than 70% plasma cells on either aspiration or biopsy (P less than 0.05). A nodular histological pattern on biopsy, however, had a higher correlation with hemoglobin levels less than 10 g/dl, and serum creatinine levels greater than 2 mg/dl, than did plasma cell number. The presence of lymphoid nodules correlated with less lytic bone lesions. The degree of fibrosis and plasma cell immaturity did not correlate with any of the clinical parameters. Our findings suggest that reports on bone biopsies should include in addition to the number of plasma cells, the pattern of plasma cell infiltration and the presence or absence of multiple lymphoid nodules.

Biopsy↗
PubMed1988

Left anterior hemiblock in otherwise healthy pilots.

We studied 15 male pilots with left anterior hemiblock (LAH) and compared them to 15 age-matched controls. Exercise testing was normal in all 15 pilots with LAH. There was no significant difference in the measurements of cardiac geometry in the 15 pilots compared to the controls, with valve thickness, mitral valve posterior motion and septal thickness also being similar in the two groups. The pilots remained asymptomatic and on active flying duty during the mean follow-up period of 52 +/- 8 months. We conclude that LAH is a benign condition in young asymtomatic men.

Adult↗
PubMed1987

Primary hepatic lymphoma presenting as symptomatic immune thrombocytopenic purpura.

A 33-year old Arabian man presented with idiopathic thrombocytopenic purpura that did not respond to steroid treatment or splenectomy. A routine liver scan performed after splenectomy showed a large mass in the liver. Four years later, massive gastrointestinal bleeding led to an emergency laparotomy, which revealed well-differentiated lymphocytic lymphoma extending from the liver to the fundus and lesser curvature of the stomach. A partial gastrectomy was performed. With chemotherapy the liver mass resolved and the platelet counts have normalized for the past 30 months.

Adult↗
PubMed1987

Usefulness of echocardiographically determined mitral leaflet motion for diagnosis of mitral valve prolapse in 17- and 18-year-old men.

Mitral leaflet motion during systole was studied by echocardiography in 102 healthy young men. Mean posterior maximal leaflet motion was 2 +/- 1 mm behind the CD line on 2-dimensionally (2-D) directed M-mode examination. On the apical 4-chamber cross-sectional view a mean area of 0.34 +/- 0.24 mm2 was contained by the mitral leaflets above the plane of the mitral anulus. Elevated values on the M-mode view (greater than or equal to 4 mm) compared with the 2-D 4-chamber view (greater than or equal to 0.70 mm2) were discordant, with 90% (18 of 20) of the elevated values found in 1 view only. Thus, there is a wide spectrum of mitral leaflet motion in asymptomatic young men. The value of the echocardiogram in diagnosis of mitral valve prolapse is questionable because any cutoff point between normal and abnormal is arbitrary and the degree of motion has not been shown to correlate with morbidity or mortality.

Adolescent↗
PubMed1987

Reduced natural killer activity in patients with Fanconi's anemia and in family members.

Natural killer (NK) activity was measured in the peripheral blood of a family with Fanconi's anemia (FA) and compared to normal controls. One of two children with FA, and 6 of 11 family members had reduced NK activity (less than 30% with an E:T ratio of 25:1) compared to none of 40 controls (p less than 0.001). On retesting 5 of 8 family members and both children with FA had reduced endogenous NK activity compared to 0 of 5 controls (p less than 0.02). The number of NK cells determined by Leu 11b antibody was not reduced in any of the family members. Augmentation with interleukin-2 (IL-2) and alpha interferon (IFN) in those with low endogenous activity was variable. Three demonstrated no response to the 2 immunomodulators, while the 4 others increased to low normal levels. We conclude that some patients with FA and their apparently healthy relatives have reduced NK activity, which appears to be secondary to an intrinsic cell defect.

Anemia, Aplastic↗
PubMed1987

Serum cholesterol levels three years before and after viral hepatitis.

The serum cholesterol levels 3 years before and 3 years after an acute episode of hepatitis in 12 men aged 21-36 were compared to those in 22 age-matched controls. Serum cholesterol increased significantly during the acute icteric phase of the illness and remained elevated for 3 years after recovery. We conclude that cholesterol metabolism does not return to the prehepatitic state even 3 years after recovery.

Adult↗
PubMed1987

Predictive value of premature ventricular contractions on the resting electrocardiogram for ventricular arrhythmias on 24 hour monitoring in asymptomatic young adults.

Between the years 1981-1984, 89 air-personnel, ages 18-45 years, underwent 24-hour ambulatory ECG monitoring at the Israel Air Force Aeromedical Center due to an incidental finding of one or more premature ventricular contractions (PVCs) on the resting supine 12-lead ECG. Complex ectopic arrhythmias (bigemini, trigemini, couplets, ventricular tachycardia, R on T phenomenon, or multifocal patterns) were observed during monitoring in 1.4% of 138 control subjects without PVCs, in 22% of those with 1 to 3 PVC X min-1 and in 68% of those with 4 or more PVC X min-1 on the resting ECG. Altogether 39(44%) of the 89 subjects with PVCs on the resting ECG had complex ectopic rhythms on monitoring. Of the 43 subjects with available follow-up data, 3 (7%) reported bouts of dizziness and light headedness which coincided with complex ectopic rhythms. In one of these three subjects, the bouts of dizziness coincided with runs of ventricular tachycardia during exercise testing.

Adult↗
PubMed1987

Low back pain in the AH-1 Cobra helicopter.

Pilots of the AH-1S helicopter maintain a vertical sitting position in the gunner's position (front seat), whereas in the pilot's seat (rear), they lean forward and to the left in order to operate the controls. A cross over study with pilots flying alternately in the front and rear positions was used to assess the effect of crew position on the prevalence of low back pain during flight. In the pilot's seat, there was an increased prevalence of pain (72.2%, 13/18 versus 55.6%, 10/18); the onset of pain was quicker than experienced in the gunner's position (64.3%, 9/14 versus 7.1%, 1/14, p less than 0.001); and the intensity was greater (85.7%, 12/14 versus 7.1%, 1/14, p less than 0.001). We conclude that posture is an important component of the low back pain experienced by helicopter pilots during flight.

Adult↗
PubMed1987

Sensitivity of the high-power field method in detecting red blood cells in the urinary sediment.

The red blood cell (RBC) content of urine specimens was determined both by direct counts by a hemocytometer and by the number of RBCs per high-power field (HPF) in the sediment by routine urine analysis. The sensitivity of a finding of 1 to 3 and 2 to 4 RBCs/HPF in detecting greater than or equal to 2,000 RBCs/ml unspun urine was 63% (73/116) and 54% (63/116), respectively. There was a wide range of values of RBCs/ml determined by direct counts for each degree of microscopic hematuria as defined by the HPF method. We conclude that examination of the urinary sediment by the HPF method is not sufficiently sensitive to be used as a screening test for the detection of microhematuria in asymptomatic subjects.

Adult↗
PubMed1987

Monocyte produced burst-promoting activity after stimulation with lymphokine.

Normal monocytes were stimulated by lymphokine(s) from a homogenous population of malignant T cells of the helper phenotype (OKT 3+/4+/6-/8-/11+). The resultant monocyte-conditioned medium after stimulation with T cell-conditioned medium (M-CM+) was assayed for burst-promoting activity. The number of burst-forming units-erythriod (BFU-E) in methylcellulose cultures of normal human nonadherent peripheral blood cells increased by nearly threefold in the presence of 5% M-CM+. This activity was lost after the conditioned medium was boiled for 20 min. The addition of 5% conditioned medium (CM) from unstimulated monocytes did not significantly increase BFU-E proliferation. We conclude that lymphokine(s) from malignant T cells of the helper phenotype stimulate normal monocytes to produce a heat-sensitive monokine that increases BFU-E proliferation.

Colony-Forming Units Assay↗