Biomedical subjects

J J Henry

Publications and source records attributed to J J Henry.

25 records · Page 2Linked to original sources

PubMed1989

Early inductive interactions are involved in restricting cell fates of mesomeres in sea urchin embryos.

Isolated intact caps of animal blastomeres, obtained from either 8- or 16-cell embryos, differentiate as swollen ectodermal vesicles. These findings agree with earlier studies demonstrating that mesomeres contribute only to larval ectoderm during normal development. In contrast, we find that pairs of mesomeres isolated from 16-cell embryos can differentiate endodermal and mesenchymal cells in a substantial number of cases (23%). Thus, mesomeres have a greater developmental potential than is realized during normal development. Further results support hypotheses that graded distributions of morphogenetic determinants exist within these embryos, since the extent of differentiation of isolated mesomeres is related to the relative position of the third cleavage plane along the animal-vegetal axis. When the third cleavage plane is subequatorial and the resulting animal blastomeres inherit a fraction of the vegetal hemisphere, more cases (39%) differentiate endodermal and mesenchymal cell types. A significant number of mesomere pairs (9-14%), however, can still differentiate endodermal and mesenchymal cells when the mesomeres are formed within the animal hemisphere. Thus, putative vegetal morphogenetic determinants may extend into the animal hemisphere in some cases. Further results indicate a temporal restriction in the developmental potential of mesomeres or mesomere progenitor cells since their differentiative capability is greater if they are isolated earlier during development. Aggregates of isolated mesomere pairs also display a decreased developmental potential when compared to isolated mesomere pairs. These results suggest that associations with adjacent cells (vegetal cells as well as adjacent mesomeres) restrict the development of mesomeres between third and sixth cleavages.

Animals↗

PubMed1988

Factors determining length of hospitalization for patients having laminectomy surgery.

The purpose of this study was to determine factors associated with length of stay for patients undergoing lumbar laminectomy. Significant differences were identified related to method of payment for hospitalization, number of doses of analgesic medications, and presence of muscle spasms. Other factors studied were sex, pre- or postoperative administration of steroids, presence of complications, age, length of surgical procedure and types of antispasmodic medications administered. The study was conducted in an urban north Texas hospital, using a retrospective review of 30 charts selected randomly. Further study of factors related to length of hospitalization is necessary in this, as well as other patient populations, especially since the advent of prospective payment.

Diagnosis-Related Groups↗

PubMed1987

Effects of oxygen radicals on substrate oxidation by cardiac myocytes.

Freshly isolated adult rat heart cells were used to study the effects of oxygen-free radicals on the myocardial oxidation of different substrates. The calcium-tolerant quiescent cells were incubated with xanthine plus xanthine oxidase as the source of free radicals. The oxidation of exogenous glucose, lactate and octanoate was severely inhibited (approx. 70%) by products of xanthine oxidase activity. Superoxide dismutase plus catalase effectively prevented the inhibition of oxidation. Cellular high energy phosphate levels were decreased in the presence of the oxygen free radical generating system although cell viability determined by Trypan blue exclusion and light microscopic assessment of normal morphology was not affected. These data suggest that oxygen free radicals decrease myocardial substrate oxidation which may contribute to the functional and ultrastructural changes in the myocardium under conditions such as reoxygenation after hypoxia and reperfusion after ischemia.

Adenosine Triphosphate↗

PubMed1987

Inductive interactions in the spatial and temporal restriction of lens-forming potential in embryonic ectoderm of Xenopus laevis.

The process of lens cell determination in amphibians is currently viewed as one involving a series of inductive interactions. On the basis of previous investigations, these interactions are thought to begin during gastrulation when the presumptive foregut endoderm and then the heart mesoderm come into contact with the presumptive lens ectoderm. This earlier period of induction is followed by the later interaction of the optic vesicle with the lens-forming ectoderm. Transplantation experiments were performed to determine the relative significance of the early and later periods of induction in the process of lens cell determination in the anuran Xenopus laevis. Various ectodermal tissues were transplanted either into the lens-forming region of open neural plate stage host embryos or over the newly formed optic vesicle of later neurula stage embryos. All transplanted tissues were labeled with the intracellular marker horseradish peroxidase to assess the exact origins of any induced lens structures. The results indicate that all nonneural ectodermal tissues have some lens-forming potential early during gastrulation; however, this potential is restricted to the lens-forming region, and perhaps nearby regions, later in development during the time of neurulation. Furthermore, the results show that the optic vesicle is not a substantial inductor of the lens in tissues that have not been previously exposed to the earlier series of inductive interactions that take place during gastrulation and neurulation. Since the optic vesicle does not appear to be a sufficient inductor of the lens, these earlier inductive interactions are, therefore, essential in the process of lens cell determination in Xenopus. These earlier inductive interactions lead to a steady increase in what may be called a lens-forming bias in the presumptive lens ectoderm during this period of development. The eventual loss in the ability of nonlens ventral ectoderm to respond to these lens inductors is presumably the result of other determinative processes that occur in this tissue.

Animals↗

PubMed1986

Substrate utilization and high energy phosphate levels of hearts from hyperdynamic septic rats.

Experiments were conducted to test the hypothesis that the previously demonstrated depression in ventricular function of rats with hyperdynamic sepsis was a result of depressed high energy phosphate levels or altered myocardial substrate utilization. Rats were inoculated with a pooled fecal homogenate, and 48 hr later their hearts were removed and studied using the Langendorff preparation. The coronaries were perfused with a hydrostatic pressure of 90 mmHg, and hearts were paced at 310-320 beats/min. Substrate oxidation was determined by supplying 14C-labeled glucose, lactate, or palmitate in physiologic concentrations, ie, 5.5, 1, and 0.6 mM, respectively. Hearts were frozen either in situ or after 40-50 min of perfusion for the determination of tissue metabolite levels. Myocardial content of high energy phosphates, total adenine nucleotides, and creatine were similar in septic animals and time-matched controls both in situ and after perfusion. Oxidation of exogenous substrates accounted for the total myocardial O2 consumption in both groups of perfused hearts. Palmitate oxidation was responsible for approximately 50% of the total O2 consumption of the heart, with glucose accounting for approximately 20% and lactate for the remainder. The percentage contribution of the three substrates to oxidative metabolism was similar in hearts from septic and time-matched controls; therefore, myocardial substrate preference was not altered by sustained sepsis. These studies also indicate that ischemia and the concomitant fall in high energy phosphates do not contribute to the myocardial dysfunction of hyperdynamic sepsis.

Adenine Nucleotides↗

PubMedDate not supplied

Routine growth monitoring and assessment of growth disorders.

Pediatric nurse practitioners have an important role in the routine monitoring of growth and the assessment of growth disorders. The development of good history-taking skills and an accurate, repeatable measurement technique are central to the success of growth assessment and evaluation. Numerous causes exist for growth disorders. The pediatric nurse practitioner can be instrumental in identifying these disorders and in making appropriate referral to a pediatric endocrinologist for further evaluation and treatment.

Adolescent↗

PubMedDate not supplied

[Adult teratoma of testicular and inguinal localization (author's transl)].

The purpose of the report is to present a patient in whom two adult teratomas presenting all the morphological benign features developed. The first teratoma is situated in the testis, the second is in the homolateral inguinal region. This association is very exceptional. Only a same case was found in literature. Several hypothesis about the mechanism of such lesions are discussed.

Abdominal Neoplasms↗