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Biomedical subjects

K L Jones

Publications and source records attributed to K L Jones.

At least 199 records · Page 11Linked to original sources
PubMed1989

Seed Dormancy in Red Rice : VII. Structure-Activity Studies of Germination Stimulants.

Many chemically dissimilar substances break dormancy of seeds, but the relationship between chemical structure and physiological activity is unknown. In this study, the concentrations of organic acids, esters, aldehydes, alcohols, and inorganic weak acids required to elicit 50% germination of initially dormant, dehulled red rice seeds (Oryza sativa) were determined. The activity of most substances was very highly and inversely correlated to lipophilicity as measured by octanol/water partition coefficients; chemicals with the highest partition coefficients required the lowest concentrations to elicit the germination response. Relative efficacy was also dependent upon the functional group; generally, monocarboxylic acids were more effective than aldehydes, esters, hydroxyacids, and alcohols. Relative hydrophobicity plots supported a modulating role of the functional group. Dormancy-breaking activity of methyl formate, formic acid, nitrite, azide, and cyanide was higher than predicted based on lipophilicity and apparently was related to molecular size; compounds with smaller molecular widths were required at lower concentrations to achieve the 50% germination response.

Journal Article↗
PubMed1988

Autosomal dominant benign neonatal seizures.

Eight individuals in two generations of a family experienced seizures neonatally or in early infancy. Evaluation in two of these infants documented an EEG pattern suggestive of seizure activity without discernible pathogenesis of their seizures. Subsequently, affected individuals had a normal neurodevelopmental outcome, although one person had later epilepsy. The benign course of this disorder and its association with adult epilepsy agree with previously reported cases from the literature.

Electroencephalography↗
PubMed1988

Laterality defects in conjoined twins: implications for normal asymmetry in human embryogenesis.

We evaluated six pairs of conjoined twins: four pairs were dicephalus, and two were of the ischiopagus type. In three of the four dicephalus pairs, the right twin had an abnormality of laterality that included a right aortic arch, reversed great vessel orientation, bilateral right-sided isomerism of the lungs, asplenia, and situs inversus of the viscera. The left twin had normal great vessel orientation and situs solitus in each case. The finding that was unique in these three dicephalus twin pairs was their fused hearts, which were similar in orientation and configuration. The fourth dicephalus twin pair had one normally rotated heart, which was located in the midline and had normally placed chambers and great vessels. Each twin of this pair had normal visceral situs. In the two pairs of ischiopagus twins, each pair had two separate hearts, with normal cardiac structure and great vessel relationships. The viscera expressed normal laterality. Documentation of a defect in laterality in the right twin in three conjoined twin pairs with fusion of the hearts, combined with the presence of normal laterality in three pairs without cardiac fusion, has implications regarding the mechanisms leading to laterality of the human embryo. We suggest that rotation of the heart initiates the embryo's process of lateralization and that the laterality defects of the viscera seen in the right twin are a result of their abnormal cardiac rotation.

Abnormalities, Multiple↗
PubMed1988

Comparison of the acute metabolic effects of 22,000-dalton and 20,000-dalton growth hormone in human subjects.

The acute metabolic effects of 20,000-dalton human growth hormone (hGH20K) in man have not previously been tested. We compared changes in concentrations of free fatty acids (FFA), glucose, and insulin in nine growth hormone deficient children following injection of 22,000-dalton intact human growth hormone (hGH22K) and the smaller variant, hGH20K. There was a significant decline (37%) in the mean FFA concentration from baseline to 1/2 hour post-injection and from baseline to 1 hour post-injection (36%) in the children given hGH22K, but no such decline was seen after injection of hGH20K. No significant differences in mean insulin or glucose concentrations were noted between the two treatment groups, and glucose and insulin concentrations did not acutely change after injection of either hormone. The results of this study indicate that hGH20K has a diminished activity for suppression of FFA as compared to hGH22K. This suggests that GH residues 32-46, missing in hGH20K, constitute all or part of the region of hGH22K producing this response, or that the different primary structures of the two hormones result in tertiary structural differences and altered biological activity.

Adolescent↗
PubMed1988

Inhibition by prednisone of growth hormone (GH) response to GH-releasing hormone in normal men.

Glucocorticoids increase GHRH-stimulated GH secretion when added in vitro to cultured monkey, rat, and human pituitary cells and when injected in vivo into anesthetized rats. Yet, in man glucocorticoids inhibit linear growth and GH secretion. To clarify this apparent disparity and to determine if glucocorticoid stimulation can augment GH release in man after direct pituitary stimulation with GHRH, we administered 1 microgram/kg GHRH dosage to seven normal men before and after a 4-day course of prednisone (20 mg, orally, three times daily). The second GHRH test was done 12 h after the last dose of prednisone was given. Prednisone significantly inhibited the mean maximal increase in serum GH after GHRH treatment [20.7 +/- 4.5 (+/- SE) vs. 6.3 +/- 2.4 micrograms/L; P less than 0.01] as well as the GH value obtained by summing and averaging the individual means of the 15, 30, 45, 60, 75, and 90 min serum GH concentrations (11.1 +/- 1.2 vs. 4.3 +/- 0.9 micrograms/L; P less than 0.05). The mean serum insulin-like growth factor I and plasma glucose concentrations were not significantly altered by prednisone administration. These results together with previous in vitro findings imply that glucocorticoid-induced inhibition of GH secretion in man does not occur at the level of the pituitary gland, but, rather, at the hypothalamus or above.

Adrenocortical Hyperfunction↗
PubMed1988

Diversified funding and programming for homemaker and home health aide services.

Homemaker-home health aide services can be the backbone of a home health agency. Due to the increased community needs of the frail elderly, the potential of abuse and neglect of both adults and children, and the challenge to delay or prevent institutionalization, homemakers and health aides are a vital component to programming for in-home services. Agencies are challenged to seek funding opportunities and move toward diversification to meet community needs.

Aged↗
PubMed1988

Coarctation of the aorta in Turner syndrome: a pathologic study of fetuses with nuchal cystic hygromas, hydrops fetalis, and female genitalia.

Congenital heart disease is a frequent feature of Turner syndrome. Although the most frequent cardiac lesion is coarctation of the aorta, a spectrum of cardiac defects occurs which is limited almost exclusively to defects associated with decreased blood flow through the left heart. We report the results of gross anatomic and microscopic dissection of 12 fetuses aborted between 16 and 26 weeks' gestation, with the classic Turner phenotype of nuchal cystic hygromas, hydrops fetalis, and female genitalia. Eight fetuses showed a consistent constellation of cardiac defects: diminution of the ascending aorta, large pulmonary artery ranging from 1 1/2 to three times the size of the aorta, large patent ductus arteriosus, and juxtaductal coarctation. Another fetus had hypoplastic left heart and aortic atresia. The remaining three fetuses had normal cardiac anatomy. The lymphatic vessels at the base of the great vessels were carefully examined in nine of the fetuses. Although there was no definite correlation between the degree of cardiac pathology and the extent of lymphatic aberrations at the base of the heart at the time of postmortem examination, the high incidence (75%) of left-sided flow defects among these fetuses, all of whom had large hygromas and severe edema, supports the hypothesis that there is a pathogenetic relationship between lymphatic obstruction and congenital heart disease in the 45,X Turner fetus.

Aortic Coarctation↗
PubMed1987

Nutritional status, glutathione levels, and ototoxicity of loop diuretics and aminoglycoside antibiotics.

Chinchillas deprived of food for 48 h prior to the administration of a combined dose of ethacrynic acid (10 mg/kg) and kanamycin (100 mg/kg) suffered a profound hearing loss. Fed animals did not demonstrate any hearing loss at the same dose levels. Drug metabolism may be the common pathway by which ototoxic agents interact, by a mechanism which is common to both the cochlea and the kidney. Glutathione (GSH) is a tripeptide which is involved in several pathways in the detoxification of active oxygen and reactive species formed during xenobiotic metabolism. The enhanced auditory dysfunction was paralleled by one-third decline in hepatic glutathione levels in the food-deprived animals. Manipulation of endogenous GSH levels may mitigate the toxicities of many of these drugs, which otherwise limit their clinical usefulness. These results also indicate that nutritional status may have important clinical implications during drug therapy.

Animals↗
PubMed1987

Changes in facial appearance during cyclosporin treatment.

Substantial changes in facial appearance developed in a group of children treated with prednisone and cyclosporin for immunosuppression after renal transplantation. In general, the children's features became coarse. There was thickening of the nares, lips, and ears, puffiness of the cheeks, prominence of the supraorbital ridges, and mandibular prognathism. The extent of the changes varied, but all eleven children followed up for more than 6 months from transplantation showed some of the changes. Patients treated with prednisone and azathioprine did not show any changes, clearly implicating cyclosporin in their aetiology. This dysmorphic syndrome along with the well-known hirsutism induced by cyclosporin may increase the risk of non-compliance with this immunosuppressive therapy.

Adolescent↗
PubMed1987

Duplication of distal 15q: report of five new cases from two different translocation kindreds.

Four children and one spontaneously aborted fetus from 2 separate families have a similar pattern of malformation secondary to duplication of distal 15q. In both families, the abnormal chromosomes were derived from balanced reciprocal translocations carried by the mothers. Clinical features common to the 4 liveborn children include appropriate birth weight, length, and head circumference for gestational age; similar craniofacial anomalies, including sloping forehead, bulbous nose, prominent nasal bridge and septum, midline crease in the lower lip, and micrognathia; arachnodactyly; joint contractures involving hands and feet; cardiac defects; and genital anomalies. The 2 infants with duplication 15q22.1----qter and deletion 13q32.3----qter died in the immediate neonatal period. The abortus, who shared the same chromosome constitution, had an omphalocele and a cephalic defect in neural tube closure. The 2 children with duplication 15q22----qter and deletion 11q25----qter survived but have severe psychomotor retardation and postnatal onset growth deficiency, at 48 and 30 months, respectively. The findings in these 5 cases plus review of the literature permit further delineation of a recognizable pattern of malformation secondary to duplication of distal 15q.

Abnormalities, Multiple↗
PubMed1987

New autosomal dominant branchio-oculo-facial syndrome.

We observed an autosomal dominant disorder of abnormal upper lip, which resembles a poorly repaired cleft lip, malformed nose with broad bridge and flattened tip, lacrimal duct obstruction, malformed ears, and branchial cleft sinuses and/or linear skin lesions behind the ears in several persons in 3 families. In each of the 3 families, an affected parent had at least one affected child. Father-to-son transmission in one of these families ruled out X-linked inheritance. Other anomalies include coloboma, microphthalmia, auricular pits, lip pits, highly arched plate, dental anomalies, and subcutaneous cysts of the scalp. Premature graying of hair occurred in the affected adults. Growth retardation, developmental delay, and hand anomalies are variable components of the syndrome.

Abnormalities, Multiple↗
PubMed1987

X-linked laterality sequence: situs inversus, complex cardiac defects, splenic defects.

The association of abdominal situs inversus, complex cardiac defects, and alterations in development of the spleen represents a developmental field complex with variable expression of altered laterality. Familial and inherited cases documenting respectively autosomal recessive and dominant inheritance have been reported. We report on the first family in which X-linked recessive inheritance of this defect has been documented.

Child, Preschool↗
PubMed1987

The umbilical cord twist: origin, direction, and relevance.

The purpose of this study was to evaluate the origin, direction, and relevance of the umbilical cord twist. We initially hypothesized that the direction of the helix or twist of the human umbilical cord at birth correlated with the eventual handedness of the child. Among 2801 singleton placentas in this study, only 5% had no twist, and the left twist outnumbered the right twist by 7 to 1, a ratio that is strikingly similar to the predominance of right-handed persons to non-right-handed persons in the general population. Forty-five 3- and 4-year-old children with previously documented cord twists were evaluated with respect to hand preference and performance. The direction of the cord twist was independent of the handedness of the child as well as the mother. We have documented an increased incidence of absent twist and right twist in association with single umbilical artery, suggesting that the impetus for the cord twist is independent on hemodynamic forces in the umbilical cord itself. We further document an increased incidence of absent twist among intrauterine fetal deaths and twins, suggesting that decreased fetal movement can impede the forces leading to normal twisting of the umbilical cord. Absence of cord twist may be associated with adverse prognosis.

Child, Preschool↗
PubMed1987

Vascular pathogenesis of unilateral craniofacial defects.

The term hemifacial microsomia refers to unilateral defects in development of structures derived from the first and second branchial arches. Recently we evaluated three unrelated children who had a similar pattern of unilateral craniofacial defects that was associated with other structural abnormalities having a disruptive vascular pathogenesis. The clinical findings in these patients suggest that one cause of hemifacial microsomia is in utero interruption of blood flow.

Adolescent↗
PubMed1987

Autosomal dominant ectrodactyly and absence of long bones of upper or lower limbs: further clinical delineation.

The association of ectrodactyly and absence of long bones of the upper or lower extremities has been recognized previously in nine families. We report 24 additional individuals in four families who are similarly affected. Two of these families manifest the unusual feature of unilateral preaxial polydactyly of a lower extremity. Data from these four families plus the nine previously reported suggest that ectrodactyly associated with absence of long bones of the upper or lower limbs is a genetically determined disorder, inherited as an autosomal dominant trait with widely variable expression or nonpenetrance.

Adult↗
PubMed1987

An immunohistochemical study of fibronectin in human osteoarthritic and disease free articular cartilage.

Fibronectin is a minor component of cartilage connective tissue matrix, which is reported to accumulate in increased amounts in osteoarthritis. The presence of raised levels of fibronectin in human osteoarthritic cartilage by immunoperoxidase localisation is confirmed. Residual femoral head articular cartilage from 17 patients with osteoarthritis contained variable but substantial amounts of fibronectin. This was localised mainly in a band within the matrix of the surface zone. No significant deposits of fibronectin were found in this or any other area of the normal specimens. Intracellular fibronectin was identified in some cells of the surface zone, indicating that it was, in part, synthesised locally. The presence and distribution of locally produced fibronectin in osteoarthritic cartilage suggest that its synthesis is a response by chondrocytes to changes in the cartilage matrix.

Aged↗