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Biomedical subjects

J A Martin

Publications and source records attributed to J A Martin.

At least 163 records · Page 9Linked to original sources
PubMed1981

Sexual development, age, and dating: a comparison of biological and social influences upon one set of behaviors.

Data from the U.S. National Health Examination Survey of 12-17-year-old youths were used to determine whether the development of the social behavior of dating is more closely linked to the level of sexual maturation or to the progression through age grades without reference to sexual maturation. Regression analyses and partial correlations show that individuals levels of sexual maturation add very little to the explained variance in dating after age had been taken into account. It appears that social pressures, based on behavior considered typical and appropriate at various ages, determines the onset of dating in adolescents. Individual rates of sexual maturation that deviate from the norm for that age have little impact on dating. These findings show how social standards can reduce dramatically the impact of individual biological processes on institutionalized forms of behavior.

Adolescent↗
PubMed1980

Cutaneous transureteroureterostomy in children with neurogenic bladders.

Our experience with 30 cutaneous transureteroureterostomies performed in children with neurogenic bladders is presented. 14 of them have been followed up for more than 5 years. The procedure is very simple and has a low percentage of immediate and late complications. Some premises to be followed regarding surgical technique in order to obtain the best possible results are emphasized.

Child, Preschool↗
PubMed1980

[Urinary lithiasis in the child (author's transl)].

The authors report a series of 130 children suffering from urinary lithiasis (essentially between the age of 4 to 6 years) and particularly in boys (2.5 to 1). There were 108 cases of reno-ureteric lithiasis as against 23 vesico-urethral. In 69 cases, pyelocalyceal lithiasis predominated. Thirty per cent of the children had bilateral lithiasis, and 19% of all cases of lithiasis were staghorn calculi. Presenting symptoms : haematuria, diffuse abdominal pain, anuria (6 cases), complete urinary retention (5 cases). Study of these cases failed to indicate whether obstruction of the upper urinary tract (14%) or infection (27%) was the cause or the effect of the lithiasis. Particularly notable were 8 cases of cystinuria (6%), 1 of glycinuria, 1 of hyperoxaluria and 7 of hypercalciuria. At least in Spain, lithiasis in children would appear to be essentially idiopathic. However, 40% of these cases of lithiasis were secondary to obstruction of the excretory tract and/or urinary infection. All types of entero-uroplasty were lithogenic (6 cases). 32% of the children had a proteus infection. Treatment : 14 children were treated medically as against 125 surgically. 70% are free of any recurrence. 7% have a residual lithiasis. The rarity of recurrences and the quality of the results obtained indicate that complete surgical treatment represents the essential feature of the treatment of urinary lithiasis in children.

Adolescent↗
PubMed1979

Congenital rubella deafness: a preventable disease.

Over a 4-year period (1972-75) an unselected sample of 568 children aged under 4 years attending the Nuffield Hearing and Speech Centre were tested for rubella antibody. Sensorineural deafness was subsequently diagnosed in 349 of these children, and 83 (24%) of this group had rubella antibody. In contrast, only 19 (9%) of the remaining 219 children in whom sensorineural deafness was excluded had rubella antibody. The seropositive and seronegative children with sensorineural deafness showed striking differences in family history, history of maternal rubella, adverse perinatal events, and presence of other defects. Congenital rubella is an important cause of deafness, and the rubella vaccination programme must be pursued more vigorously if this serious defect is to be prevented in the future.

Abnormalities, Multiple↗
PubMed1979

EMG comparison of quadriceps femoris activity during knee extension and straight leg raises.

Both knee extension and straight leg raises have been used to rehabilitate atrophied quadriceps musculature following knee immobilization. A comparison of the tension developed during these two exercises was made in each of the three surface quadriceps muscles (quadriceps femoris, vastus lateralis, vastus medialis) at three different levels of activity (20%, 50%, and 80% of 1RM). Integrated EMG (m Volt-seconds) was used to measure tension developed during a seven second contraction. Tension developed was significantly greater during a seven second contraction. Tension developed was significantly greater during knee extension than during straight leg raises at each exercise intensity. For both exercises and at all three exercise levels, the vastus lateralis was the most active; the vastus medialis was the least active. The difference between knee extension and straight leg raises became greater with increasing levels of activity. Therefore, unless contraindicated by chondromalacia of lack of knee flexibility, knee extensions should be used for post-surgical knee rehabilitation. The greater tension development would lead to a more rapid return of strength, and therefore quicker rehabilitation.

Action Potentials↗
PubMed1978

Sterol synthesis. Chemical synthesis, structure determination and metabolism of 14 alpha-methyl-5 alpha-cholest-7-en-3 beta, 15 beta-diol and 14 alpha-methyl-5 alpha-cholest-7-en-3 beta, 15 alpha-diol.

14alpha-Methyl-5alpha-cholest-7-en-3beta,15beta-diol and 14alpha-methyl-5alpha-cholest-7-en-3beta,15alpha-diol have been prepared by chemical synthesis. Unequivocal establishment of these structures was based upon X-ray crystallographic analysis of 3beta-p-bromobenzoyloxy-14alpha-methyl-5alpha-cholest-7-en-15beta-ol and was supported by other spectroscopic data. Spectroscopic data were presented for the following compounds prepared in this study: 3beta-benzoyloxy-5alpha-cholest-8(14)-en-15-one, 3beta-benzoyloxy-14alpha-methyl-5alpha-cholest-7-en-15-one, 3beta-benzoyloxy-14alpha-methyl-5alpha-cholest-7-en-15beta-ol, 14alpha-methyl-5alpha-cholest-7-en-3beta, 15beta-diol, 14alpha-methyl-5alpha-cholest-7-en-3beta, 15alpha-cholest-7-en-15beta-diol, 14alpha-methyl-5alpha-cholest-7-en-3beta, 15alpha-diol, 3beta, 15alpha-bis-benzoyloxy-14alpha-methyl-5alpha-cholest-7-ene, 3beta-p-bromobenzoyloxy-14alpha-methyl-5alpha-cholest-7-en-15beta-ol and 3beta, 15beta-bis-p-bromobenzoyloxy-14alpha-methyl-5alpha-cholest-7-ene. Studies of the metabolism of [16-3H]-14alpha-methyl-5alpha-cholest-7-en-3beta, 15beta-diol and [16-3H]-14 alpha-methyl-5 alpha-cholest-7-en-3beta, 15alpha-diol in liver homogenates of female rats indicated that only the 3beta, 15beta-diol was convertible to cholesterol.

Animals↗
PubMed1976

Studies on the binding of haemoglobin by haptoglobin using electrofocusing and gradient electrophoresis.

1. Gel electrofocusing followed by gel gradient electrophoresis separated the haptoglobins and their complexes with haemoglobin into characteristic two-dimensional patterns of protein bands. 2. Molecular weights of 107 000, 139 000 and 168 000 were obtained for the three bands seen after a purified preparation of haptoglobin type 1 was partially saturated with haemoglobin. This indicated that free haptoglobin, the intermediate haptoglobin-haemoglobin complex containing one half-haemoglobin and the saturated complex with two half-haemoglobins were present. 3. The three proteins showed considerable microheterogeneity and gave a number of isoelectric points in the pH ranges 4.58-4.77, 5.20-5.40 and 5.74-5.93, free haptoglobin type 1 being the lowest group. These ranges were all 0.15-0.30pH units lower if other values were taken for the isoelectric points of markers used to calibrate the pH gradient. 4. All three proteins were present over a wide range of haemoglobin concentrations, from 0.5% to 92% of that required for saturation. This would be expected if both binding sites have similar affinities for haemoglobin.

Binding Sites↗
PubMed1976

Pulmonary giant cell carcinoma.

Pulmonary giant cell carcinoma is one of the most highly malignant neoplasms of the lung. Eighteen patients with this tumor are presented. Histologically the neoplasm is composed of a preponderance of multinucleated giant cells, round cells, and spindle cells. Some of the most differentiated tumors show adenocarcinomatous foci and ultrastructural features of secretory epithelium favoring its classification as a variant of pulmonary adenocarcinoma. The giant cells of this neoplasm can be differentiated from those encountered in undifferentiated large cell carcinoma and epidermoid carcinoma by the abundant cytoplasm, the presence of more nuclei and nucleoli, and the significant degree of phagocytosis. The clinical picture and roentgenographic findings present no pathognomonic features.

Adult↗
PubMed1975

Electrofocusing followed by gradient electrophoresis: a two-dimensional polyacrylamide gel technique for the separation of proteins and its application to the immunoglobulins.

A two-dimensional polyacrylamide gel technique for the separation of proteins is described. Electrofocusing in a 3.5% polyacrylamide gel is followed by electrophoresis through a 4-24% concave polyacrylamide gel gradient. The method resolves a large number of serum proteins and produces highly reproducible patterns. It is particularly useful for studies involving proteins of high molecular weight, such as alpha2-macroglobulin, beta-lipoprotein and IgM. The application of the technique to the immunoglobulins in pathological sera is reported.

Blood Proteins↗