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Biomedical subjects

J Cohn

Publications and source records attributed to J Cohn.

At least 37 records · Page 2Linked to original sources
PubMed1984

Serum iron, serum transferrin and transferrin saturation in healthy children without iron deficiency.

Serum iron, serum transferrin and transferrin saturation were studied in 253 healthy, non-anaemic children 4, 8 and 13 years old, and in 60 healthy, non-anaemic adults having serum ferritin values greater than or equal to 15 micrograms/l. One hundred and ninety-six children had serum ferritin values greater than or equal to 15 micrograms/l (i.e. replete iron stores), 35 had intermediate ferritin values from 10-14 micrograms/l and 22 had ferritin values less than 10 micrograms/l (i.e. depleted iron stores). Iron replete children showed a gradual rise in serum iron and transferrin saturation values with age. Serum iron and transferrin saturation values were lower (P less than 0.001, P less than 0.0001) and transferrin values higher (P less than 0.0001) in iron replete children compared to adults. Iron replete children had a 2.5 centile transferrin saturation value of 5%; 19.9% of these children had saturation values less than 15% and 8.2% had values less than 10%. In iron depleted children a transferrin saturation value less than 7% yielded the highest diagnostic efficiency as regards exhausted iron stores, although with a low predictive value of a positive test. The transferrin saturation is unsuitable as a single diagnostic criterion in the evaluation of iron deficiency in children and should always be combined with other indicators of iron status.

Adolescent↗
PubMed1984

Quantitative analysis of wide-field endothelial specular photomicrographs.

Samples from the center of a wide-field specular micrograph adequately assessed cell density and frequency distribution of cell areas. A preliminary analysis of the spread of values indicated whether an increased sample size was required. An algorithm determined how large a sample taken from the central photograph (three, five, or nine rectangles) was necessary to permit detection of a 10% change in cell area. This analysis of sample size also indicated that sampling by small-field specular microscopy was not representative of the surrounding square millimeter of corneal endothelium.

Cell Count↗
PubMed1984

Specular microscopy of hard contact lens wearers.

Wide-field specular microscopy, slit-lamp examination, and pachometry were performed on 22 successful hard contact lens wearers and 22 controls matched for age, race, sex, and refractive error. A minimum of 600 cells per control and 1200 per contact lens wearer were manually digitized from the specular photomicrographs. Frequency distributions of cell areas were compared between the two groups using the parameters of mean, median, standard deviation, coefficient of variation, skewness and kurtosis. Slit-lamp examination was normal and there was no significant difference in corneal thickness between the patient group and the control group. Comparison of mean, median, and standard deviation also revealed no significant difference, but skewness (P less than .001), kurtosis (P less than .001) and coefficient of variation (P less than .004) were greater in the hard contact lens wear group. Hard contact lens wearing time correlated with increasing pleomorphism (P less than .05). Specular microscopy also revealed morphologic changes including deep stromal striae, intra- and extracellular "blackout" areas, and clustering of extremely small and large cells. The possible relationship between endothelial hypoxia and structural stromal changes are discussed.

Adult↗
PubMed1983

Antibodies to herpes simplex and Epstein-Barr viruses in Faroese children: association with sibship size, height and age.

Antibody to herpes simplex virus (HSV) type 1 and Epstein-Barr virus (EBV) capsid antibody were determined in 333 children from the Faroe Islands, aged 4, 8 and 13 years. An analysis of multi-way frequency tables was performed, testing seropositivity for each virus against combinations of the following variables: sibship size, birth order, mother's age at birth, birth weight, actual height and weight, age and sex. HSV-seropositivity was associated to sibship size, height and age, while EBV-seropositivity was related only to age.--It is discussed how the findings fit into epidemiological patterns described for Hodgkin's disease and multiple sclerosis, which are both supposed to be of viral origin. Our results suggest that HSV, but not EBV, may be among the candidates to be considered.

Adolescent↗
PubMed1981

Intact megakaryocytes in the venous blood as a marker for thrombopoiesis.

A total of 110 children, aged 0-15 years, were investigated for circulating megakaryocytes in cubital venous blood using the saponin-haemolysis leucoconcentration technique. The average number of megakaryocytes decreased from 17.8 per ml blood in the first year of life to 5.5 after the 6th year, which is the same value as in adult humans. The intact thrombocytogenic megakaryocyte value decreases from about 40% in the first year of life to only a few percent (less than 5%) after the 10th year, the same value as in adult humans. There was a significantly higher number of megakaryocytes in children aged 0-6 years than in those aged 7-15 years. We concluded that occurrence of intact megakaryocytes greater than or equal to 25% in the venous blood is a sign of a normal thrombopoietic activity in the bone marrow, and the percentage of intact megakaryocytes in cubital venous blood reflects the decrease in thrombopoiesis in the bone marrow of fingers, hands and forearms during childhood. The decline in thrombopoietic activity is concentrated in three periods: 1-3, 6-7, and 10-11 years. An occurrence of intact megakaryocytes greater than 5% in venous blood draining organs or bone marrow is a sign of some thrombopoietic activity.

Adolescent↗
PubMed1981

Noninvasive cardiopulmonary monitoring.

Contrast dilution curves have been utilized for evaluation of hemodynamic function. Noninvasive techniques for this purpose usually have been qualitative, expensive, and cumbersome with minimal applicability to the newborn infant. The technique of roentgen densitometry has been utilized to screen children with heart murmurs. Characteristic curve patterns were identified for normal subjects and for patients with shunts with correlation to catheterization data. This technique is now being applied in a quantitative fashion to estimate cardiac output and left-to-right ductal shunts. Cardiac output volumes were inversely proportional to the difference of the second moments of the dilution curves obtained--the second moment being a measurement of the peak dispersion. The estimation of the percent of left-to-right shunt is related to the exponential decay of the left-sided curve.

Absorptiometry, Photon↗
PubMed1980

Persistence of viral hepatitis A and B in an isolated Caucasian population.

The persistence of viral hepatitis A (HAV) and hepatitis B (HBV) in the Faroe Islands, a Caucasian, high sanitary standard, isolated area, was studied by means of notified clinical cases of hepatitis and by specific antibody testing of population samples. Large epidemics of hepatitis occurred on the Faroe Islands in 1928-1930 and 1955-1958, although sporadic cases have been continuously recorded. Presence of antibody to HAV (anti-HAV) was confined to age groups exposed to the epidemics, while antibody to HBV surface antigen (anti-HBs) was demonstrated in all age groups, including children. This study provides further evidence for the concept of HAV as a self-limited infection, unable to maintain itself by chronic virus carriers. HBV, by contrast, again is shown to survive even in small populations with high sanitary conditions and to have no recognizable risk factors.

Adolescent↗
PubMed1980

Asbestos, lead, and the family: household risks.

Although the intrafamilial transmission of infectious diseases has long been recognized, the induction of environmental disease in household contacts is being increasingly documented and requires a higher index of suspicion. An incidental radiographic finding, such as pleural thickening or calcification, or even interstitial pulmonary fibrosis in a young person without obvious occupational exposure to asbestos, should prompt the physician to clarify the parental occupational history. Likewise, unexpected evidence of lead induced abnormalities, such as elevated blood lead and/or erythrocyte protoporphyrin levels, should focus the examiner's attention on possible intrafamilial transmission, treatment, and prevention.

Adult↗
PubMed1979

Glucose-6-phosphate dehydrogenase deficiency in a native Danish family. A new variant.

Deficiency of red cell glucose-6-phosphate dehydrogenase was found in a native Danish family, in which 2 boys suffered from severe haemolytic anaemia. The mother and 3 sisters of the boys were heterozygotes for G-6-PD deficiency. The biochemical investigations indicate that this deficient G-6-PD is very similar to the Mediterranean variant; however, this variant gene may represent another example of G-6-PD 'Helsinki' or an unique variant with properties similar to G-6-PD B(--).

Adult↗